1

Statement of originality

2

Acknowledgements

I would like to thank all of the participants for giving up their free time and

taking part in this study. I would like to thank my brother, Richard Jahn for

inspiring me to begin martial arts and giving me the tools I needed to

progress in my career. I would like to thank my Muay Thai coach, Wech

Pinyo for all of the hours of hard work he has spent with me and having

the faith in me to become a professional fighter.

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Abstract

Introduction

Muay Thai is a combative sport in which competitors punch, kick, knee, elbow and grapple their opponents. The roundhouse kick is considered a fundamental weapon in Muay Thai which targets the side of the head, jaw, shoulders, rib cage, abdomen or legs of the opponent. The aim of the study was to determine the kinematic factors most closely related to a high velocity roundhouse kick. It was hypothesised that the speed of the heel during the final phase would be the most influential factor in producing a high velocity kick. The subjects used for this study were 6 Muay Thai practitioners recruited from ‘Hybrid MMA’ gym, Plymouth. Subjects mean age was 24.1 (4.2) yrs with between 6 months and 12 years’ experience. Subjects performed one maximal roundhouse kick on Thai pads. Three-dimensional analyses were enabled with Qualisys motion capture system. The speed of the heel immediately before impact is the most influential factor in producing a high velocity roundhouse kick. A significant and positive correlation between thigh length (r=0.647, P=0.009), shank length (r=0.984, P=0.003) and final heel velocity was found. The maximum linear velocity at any joint immediately before impact was found in the heel which was in accordance with the hypothesis. However, the summation of forces was not evident in this study. The speed of the heel is dependent on the speed of the knee and the length of the shank. This data suggests that athletes with greater thigh length, and more importantly, shank length may have a mechanical advantage in martial arts kicking over participants with shorter measures and may wish to begin training in Muay Thai or another striking art. This finding may also be advantageous for talent identification scouts.

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Contents Page

Title Page

Statement of Originality

Acknowledgements

Abstract

Contents

List of Figures

List of Tables

Chapter one – Introduction

1.1 Introduction

1.2 Aims

1.3 Hypothesis/Research Questions

1.4 Delimitations

1.5 Limitations

1.6 Definition of Terms

Chapter Two – Literature Review

2.1 Introduction to the Literature

2.2 Kinematics

2.3 Kinematics Data Collection

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2.4 Anthropometry and Talent Identification

2.5 kicking literature - General

2.6 Kicking Literature – Martial Arts

2.7 Kicking Kinematics

2.8 Summary

Chapter Three – Method

3.1 Participants

3.2 Equipment

3.3 Protocol

3.4 Data Analysis

Chapter Four - Results

4.1 Table 1 -

Chapter Five - Discussion

Chapter Six – Conclusion

Reference List

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Appendices

Appendix One – Warm up

Appendix Two - NHANES III anthropometric measures protocol

Appendix Three – Subject data

Appendix Four – Subject one Pelvis angles

Appendix Five – Subject one Pelvis angular velocity

Appendix Six – Subject one Linear Velocities of the Kicking Leg

Appendix Seven - Subject one Linear Velocities of Right Arm

List of Tables

Table No.

1 Final linear velocities of the joints of the kicking leg

2 Total duration of each phase of the kick

3 Correlations of the kinematic variables

Figure No.

1 Camera Set up

2 Average linear velocities of the kicking leg

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3 Mean Joint Contributions of the Kicking Leg

4 Average linear velocities at the joints of the right arm

5 Angular velocity at the pelvis

6 Angles at the Pelvis During Kick

7 Deterministic model of a roundhouse kick

8 Print screen of the XY, YZ and XZ axis

1.1 Introduction

Muay Thai is a combative sport in which competitors punch, kick, knee, elbow

and grapple their opponents. Professional male and female fighters compete in

5 rounds of 3 minutes with a two minute break between rounds. Fights are

decided by knockout or by the three umpires in accordance with a point system

(Delp, 2004). The roundhouse kick is considered a fundamental weapon in

Muay Thai which targets the side of the head, jaw, shoulders, rib cage,

abdomen, or legs of the opponent (Ruerngsa et al. 2000). Data shows that the

force generated by a kick in "Thai Boxing" can easily cause neurological

damage, skull fractures, facial bones and ribs (Sidthilaw, 1997).

According to official Muay Thai rules (muaythaionline, 2012), some of the best

scoring techniques in Muay Thai include knocking an opponent to the floor with

a concussive blow, unbalancing an opponent with kick and immediately

following with a strong striking technique, knocking an opponent off their feet

with a kick and landing an attacking technique that results in an opponent

turning their back on the attacking boxer. Therefore, kicks are the primary

attacking skills used in Muay Thai as the target area for kicking is larger (legs,

8

torso, arms and legs), legs are longer than arms and can therefore reach

further, and kicking transfers a greater impact to the opponent than punching.

The roundhouse kick is one of the most frequently used foot skills in

Taekwondo sparring matches because of its usefulness in attack and counter-

attack, short execution time, and high chance to score (Kim et al., 2010). In

fighting conditions at high standards of competition, the speed of kicks plays a

crucial part in successful attacks (Pozo et al., 2011).

Falco (2009) simply describes the roundhouse kick as a multi-planar skill,

starting with the kicking leg travelling in an arc towards the opponent, keeping

the knee in a chambered position. The knee is extended in a snapping

movement, striking the opponent with metatarsal part of the foot extended.

When Kim et al. (2010) studied the effects of target distance on pivot hip, trunk,

pelvis, and kicking leg kinematics in Taekwondo roundhouse kicks, they divided

the body into four parts for ease of analysis: kicking leg, support leg, pelvis, and

upper body. The kick was then described in more detail: The centre of mass of

the kicking foot travels linearly in a semi-circular fashion to the target. The

support leg serves as a fulcrum or pivot hip while the kicking leg performs the

kick. The upper body is utilised as a counter-movement tool and aids in balance

while the pelvis acts as a convergence point for this to take place. The linear

motion of the pivot hip, angular motion of the pelvis about the pivot hip and

angular motions of the kicking leg joints combined create the linear velocity of

the kicking foot. The trunk counters the angular motion of the pelvis and kicking

leg for both linear and angular equilibrium.

Ascertaining which factors are important in developing high velocity kicks will

enable fighters and coaches to establish training programs that centre around

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these factors. This information can assist with the design of training

programmes based on quantitatively determined factors which equate to a high

velocity kick. Recognition of these factors can aid coaches in the development

of technique-orientated drills, which may speeding up the learning process.

(Shan and Westerhoff, 2005).

There is evidence of Muay Thai being practiced as early as 1781 (Ruerngsa et

al. 2000) and so Muay Thai and many other martial arts appear to be very

traditional in their approach, and have not been biomechanically analysed as

often as many other modern sports. Technology is now beginning to play a

considerable role in assisting martial artists to gain an advantage in training and

in competition (Pearson, 1997). Muay Thai is rapidly increasing in popularity

and has an estimated one million participants worldwide (Gartland et al., 2001).

As Muay Thai raises its profile, demonstrated by the birth of the Muay Thai

Premier league and by its popularity in mixed martial arts, it should be studied

more scientifically. The Muay Thai roundhouse kick has acquired minimal

recognition in scientific research to date which is surprising given the role it

plays in combat sports.

1.2 Aims

The aims of this study were to;

a) Ascertain whether or not the summation of speed is evident in the Muay Thai

roundhouse kick

b) Determine the kinematic variables that are most closely related to a high

velocity roundhouse kick.

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c) Investigate the correlation between anthropometric data and kick velocity.

d) Develop a deterministic model in order to depict all of the mechanical factors

that determine velocity in a Muay Thai roundhouse kick.

1.3 Hypothesis

a) The maximum linear velocity at the hip will precede the maximum linear

velocity at the knee and the maximum linear velocity at the knee will precede

the maximum linear velocity at the heel. Peak velocity at the ankle will be

greater than that of the knee and peak velocity of the knee will be greater than

that of the hip.

b) The greatest angular velocity and linear velocity at any joint in any limb will

be seen at the pelvis during phase one of the kick and at the heel immediately

before impact respectively.

c) There will be a significant positive correlation between limb/segment length

and kick velocity.

d) Length of the thigh and shank will be important factors in determining the

velocity of the Muay Thai roundhouse kick.

1.4 Delimitations

The subjects used in this study were 6 males who trained at “Hybrid

MMA” in Plymouth, Devon were able to attend UCP Marjon, Plymouth at

the allocated time.

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Subjects were asked to attend the testing session at the sports

laboratory, UCP Marjon, Plymouth.

Subjects underwent a standardised dynamic warm up typical of a Muay

Thai class in order to replicate training and competition.

Only the 4th kick that the subjects performed was analysed.

Two Thai pads were held as a target for the kick. The height and

distance of these pads were at the subjects’ discretion.

Kinematic data was acquired using videography collected by Qualisys

Motion Capture System.

Knee and heel angular velocity was not measured

1.5 Limitations

Moderating variables were not monitored. Day of the week, time of day,

daily activities, training schedule and diet were not noted.

Subjects movement before the heel left the ground and recovery phase

were not analysed.

Left foot and left hand placement were not analysed.

The sample size was relatively small

Subjects were of mixed ability and experience levels

Due to the complex movement of the kick and the relatively low number

of cameras, not all reflective markers could be captured in all frames.

1.6 Definition of Terms

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Muay Thai: a combative sport in which competitors punch, kick, knee,

elbow and grapple their opponents.

Taekwondo: a form of unarmed self -defence which focuses on

kicking techniques.

Final heel velocity: the velocity of the heel immediately before impact

Chapter Two – Literature Review

2.1 Introduction to the Literature

The aim of the literature review is to display the literature relevant to the present

study and to highlight gaps in the research. An overview of general kinematics

will be presented which looks at analysing methods and the development of the

deterministic model used for qualitative analysis. An overview of anthropometry

and talent identification will then look at how anthropometric measures may or

may not have an effect on physical performance and how this information can

be used in the process of talent identification. General kicking literature and

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martial arts kicking literature will be analysed before discussing kicking

kinematics, kinematics data collection and the summation of speed. The main

points from the chapter will then be summarised.

2.2 Kinematics

To understand the sources of motion of a Muay Thai kick, a method for

describing motion is required. “The term “kinematic” is used to describe the

study of motion with no regard to its cause” (Chapman, 2008 p15) and is one of

the most basic types of analyses that may be conducted because of this. To

make the study of movement easier, movements are classified as either linear,

angular or both (general) (McGinnis, 2005). A kinematic analysis describes the

positions, velocities and accelerations of bodies in motion (Hammil and

Knutzen, 2009). Two things are necessary for motion to occur: space and time

– space to move in and time during which to move (McGinnis, 2005).

Linear kinematics can be defined as straight line motion which occurs when all

points on a body or an object move the same distance over the same time

(Hamill and Knutzen, 2009). Displacement is the straight line distance in a

specific direction from starting position to final ending position. Displacement is

a vector quantity; this means it has a size associated with it as well as a

direction. “Velocity (which is also a vector) is displacement of an object divided

by the time it took for that displacement” (Hammil and Knutzen, 2009 p308-

315).

The subset of kinematics that deals with angular motion is angular kinematics.

Angular motion occurs when all parts of a body move through the same angle

but do not undergo the same linear displacement (Hammil and Knutzen, 2009).

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Angular displacement can be defined as the change in the angular position or

orientation of a line segment. Angular velocity is calculated as the change in

angular position or the angular displacement, that occurs during a given period

of time and angular acceleration is the rate of change in angular velocity, or the

change in angular velocity occurring over a given time.

The roundhouse kick starts in the sagittal plane and finishes in the transverse

plane because the target has a vertical surface that is perpendicular to the

ground. The roundhouse kick appears to involve motion in more than one plane

which makes three-dimensional analysis essential (Pearson, 1997).

2.3 Kinematics Data Collection

The recording of human movement in sport can be formally stated as: to obtain

a record that will enable the accurate measurement of the position of the centre

of rotation of each of the moving body segments and of the time lapse between

successive pictures (Bartlett, 2007). Despite kicking being three-dimensional in

nature, most kinematic research conducted has been recorded using two-

dimensional aparatus (Lees and Nolan, 1998).

The main method currently used for recording and studying sports movements

is digital videography. One of the strengths of videography is that it enables the

investigator to record sports movements not only in a controlled laboratory

setting, but also in competition. Advanced measurement systems and analytical

techniques have been frequently used to further the understanding of kicking

and the factors that influence kicking performance (Lees, 2010). Three-

dimensional analysis can also provide enlightenment on normative

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characteristics which are generally evident in highly-skilled athletes (Shan and

Westerhoff, 2005).

There are many benefits of using three-dimensional recording and analysis as

opposed to two-dimensional. Three-dimensional recording analysis has more

complex experimental procedures and can show the body’s true three-

dimensional movements. It requires less digitising time and has fewer

methodological problems, such as the transformation of coordinates from the

video image to the ‘real world’ movement plane. Three dimensional analyses

also allow angles between body segments to be calculated accurately, without

viewing distortions. It also allows the calculation of other angles that cannot, in

many cases, be easily obtained from a single camera view. One example is the

horizontal plane angle between the line joining the hip joints and the line joining

the shoulder joints, which can be visualised from above even if the two cameras

were horizontal. Finally, it enables the reconstruction of simulated views of the

performance other than those seen by the cameras (Bartlett, 2007).

A deterministic model can assist in the understanding of the kinematic factors

involved in a Muay Thai roundhouse kick. It is a model that determines the

relationships between an outcome and the biomechanical factors that produce it

(Hay & Reid, 1988a). Hay (1984) states that a deterministic model should have

two distinguishing features. First, the model is made up of mechanical quantities

or appropriate combinations of mechanical quantities. Secondly, all the factors

included at one level of the model must completely determine the factors

included at the next highest level. It is this second feature that leads us to refer

to these types of models as deterministic models.

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Hay and Reid (1988a) described the steps in developing a deterministic model;

the first step is to identify the primary goal, result/outcome of the performance to

be investigated. The outcome of a performance can be an objective measure

(e.g. distance, height, time, etc.) or a subjective measure (e.g. points awarded

in gymnastic and diving competition). The next step is to identify those factors

that produce the result. The factors included in the model should normally be

mechanical quantities wherever possible and each factor should be completely

determined by those factors that are linked to it from below. Hay and Reid

(1988b) also stated that this type of analysis aims to supplement whatever

experience the sport scientist or coach might have and to channel or direct the

analysis in a logical, systematic fashion, eliminating the risk of overlooking

influential factors.

In a review of the use of the deterministic model written by Chow and Knudson

(2011) it was summarised that the deterministic model approach provides a

strong theoretical or mechanical platform to examine the importance of various

factors that influence the outcome of a movement. Studies which have used

these models in biomechanics demonstrate their applicability in depicting

important mechanical criterion in human movement. However, Glazier and

Robins (2012) have since critically analysed the aforementioned paper and

concluded that although deterministic models may provide a useful starting

point for sports biomechanists examining the mechanical aspects of athletic

performance, they have inherent weaknesses that limit their practical

application. Specifically, their inability to provide substantive information about

coordinative movement patterns or ‘technique’ suggests that sports

biomechanists must explore alternative paradigms and theoretical frameworks if

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they are to fulfil their main aims of improving performance and reducing injury

risk.

Once the relationships between a movement outcome and the biomechanical

factors that produce it have been defined, training strategies can be adopted by

the coach to develop these components. For instance, if the linear velocity at a

certain joint in a particular phase of the kicking motion was found to be

important, then specific technical work or strength and conditioning

programming can be employed to attain the desired adaptation.

2.4 Anthropometry

Anthropometry is the study of the measurement of bone, muscle, and adipose

tissue in the human body (NHANES III 1988). The field of anthropometry

encompasses a variety of human body measurements. Weight, stature

(standing height), recumbent length, skinfold thicknesses, circumferences

(head, waist, limb, etc.), limb lengths, and breadths (shoulder, wrist, etc.) are

examples of anthropometric measures.

The height and body size of an individual represents a factor that is generally

believed to affect the outcome of physical tests (Jaric, 2003). Indeed, some

authors often report data normalised for body size, rather than non-normalised

results. This may suggest that anthropometric variables could be a prediction of

performance.

The ability of a fast bowler to attain greater ball release speeds has been

suggested to be related to a bowler’s anthropometry (Glazier et al., 2000;

Portus et al., 2000; Stockill &Bartlett, 1996). Junior international fast bowlers

have slower ball release speeds than senior international fast bowlers due to

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longer upper limb lengths and higher angular velocities of the humerous

(Stockill and Bartlett, 1994). In this study ball release speed positiveky

correlated with total arm length (860 ± 36 mm; r = 0.583, P < 0.05), suggesting

that the most influential factor was radial length. Glazier et al. (2000) studied the

anthropometric and kinematic influences on release speed in mens fast-medium

bowling and found that angular velocity of the bowling humerus had a poor

correlation with ball release speed. It was also concluded in this study that

radial length was the dominant factor due to high correlations between ball

release speed and total arm length. It was found that a measurement of 0.1m at

the radial segment lead to a speed increase of 3.3m/s. Therefore, a more

efficient proximo-distal transfer should occur when a greater speed at this

segment is reached.

Van den Tillaar and Ettema (2004) conducted a study measuring the

relationship between maximum isometric strength and maximum velocity in

overarm throwing for male and female experienced handball players. Results

showed a significant and positive correlation between maximal isometric

strength and throwing velocity in men (r=0.43, P=0.056) and women (r=0.49,

P=0.027). Vila et al.(2009) studied the relationship between anthropometric

parameters and throwing velocity in water polo players and found significant

(p˂0.05) and positive correlations between throwing velocity and BMI (r=0.477),

flexed arm girth (r=0.479) and femur breadth (r=0.572). Factors influencing ball

throwing velocity in young female handball players was investigated by

Zapartidis et al. (2009) where it was found that throwing velocity significantly

(p< 0.05) and positively correlated with body height (r=0.335), arm span

(r=0.340), hand length (r=0.288) and hand spread (r=0.368).

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In contrast, Skoufas et al. (2004) found that throwing velocity is not correlated to

the body height (r=0.236, p=0.073) and the arm and forearm length were not

significantly correlated to the throwing velocity (r=0.167, p=0.206 and r=0.256,

p=0.051, respectively) when exploring the relationship between the

anthropometric variables and the throwing performance in handball. However,

arm span (r=0.342, p=0.008), length of hand (r=0.331, p=0.010) and width of

hand (r=0.390, p=0.002) significantly and positively correlated to throwing

velocity. Therefore, in this study, the last segment in the chain (the hand) had

the most influence on throwing velocity.

2.5 General kicking literature

In general, data is predominantly related to the kicking leg (Lees et al., 2010),

but other limbs are receiving more attention in the literature (Scurr and Hall,

2009; Bezodis et al., 2009; Ball, 2008; Shan and Westerhoff, 2005). Ball (2008)

considered the biomechanics of distance kicking in Australian rules football and

found that the foot speed and shank angular velocity to be 26.4 m/s and 1676°/s

respectively. Foot speed is significantly higher than that found in Dorge et al.

(2002) study where values of 18.6 m/s were recorded in experienced football

players. However, shank angular velocity at ball contact was similar in both

studies; 1676°/s in Australian rules football and 1610°/s in the experienced

soccer players. According to Ball (2008), the major contributor to maximal

kicking distance was greater foot speed and large shank angular velocities at

ball contact

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Foot velocities in soccer kicking have been recorded at 23.6m/s using a three-

dimensional cinematographic technique at 200 Hz (Nunome et al., 2006). Dorge

et al., (2002) reported that the velocity of the foot is a product of the linear

velocity of the knee and the angular velocity of the shank. Results from this

study show that the angular velocity of the shank was not at its maximum at the

moment of impact. Therefore, the linear velocity of the centre of mass of the

foot is the best measure of the success of a kick. Nunome et al., (2006)

suggests that there is a strong link between foot swing velocity and ball velocity

in soccer. This implies that to achieve maximal performance, the energy that

has been developed should not be reduced prior to ball contact. Dorge et al.

(2002) did, however, report a reduction in angular and/or linear velocity of the

kicking leg immediately before ball impact.

The measurement of three-dimensional kinematics of the upper extremity has

generally not received as much scientific attention as that of the lower limb (Rab

et al., 2002). There is a growing consensus that kicking foot velocity is the result

of actions of the whole body (Lees et al., 2010). Only one study (Shan and

Westerhoff, 2005) has used full-body three-dimensional motion capture and

modelling to examine kicking. The results of this study revealed that movement

of the upper body contributed considerably to skill effectiveness. It was also

concluded that a skilled player will rotate the trunk and extend and abduct the

arm on the non-kick side in order to form a tension arc at the beginning of the

step. The trunk flexors, hip flexors and quadriceps lengthen before their

contraction due to conditions provided by the tension arc. The use of the

stretch-shortening cycle in this instance should potentially create larger muscle

forces which may increase the effectiveness of the kick.

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Actions in soccer such as free kicks, goal kicks, penalty kicks and instep kicks

often involve kicking with the arm swaying. Swaying the non-kicking side arm

when running up to the ball may provide more strength to the kick due to the

muscle pre-lengthening and stretch of the swaying arm (Shan and Westerhoff,

2005). Ashby and Heegaard (2002) report that arm swaying motion is used to

maintain balance and increases the velocity of the body’s centre of gravity in

order to improve standing long jump performance.

This literature suggests that in sports such as soccer and rugby, the greatest

velocity at the most distal segment (the foot) results in the greatest ball velocity.

The movement of the upper body may also considerably contribute to skill

effectiveness.

2.6 Martial arts kicking Literature

Sorenson (1996) states that in order to determine the contribution of each joint

velocity to the final velocity (in this case the heel) of a specific movement, it is

necessary to study the total duration of the movement. A study by Falco et al.,

(2009) reviewed the total duration of the Taekwondo roundhouse kick in elite

and non-elite male athletes and found a mean time of 0.38 (+0.27) seconds

while Tang et al., (2007) found mean values of 0.6 (+.068) seconds and Boey

and Xie (2002) reported a mean time of 0.33 seconds.

Interestingly, reaction time needed to start a counterattack movement or to

avoid the attack has been reported by Vieten et al. (2007) at 0.34seconds. This

is the only study of its kind and could be considered vital when assessing the

total time taken to perform a roundhouse kick; if a kick takes more than

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0.34seconds then it is entirely possible for the opponent to have begun a block,

counter attack or an evasive move in order to avoid the strike. It has been

suggested that there several blocks (Delp, 2004) and techniques in which to

counter attack a roundhouse kick (Ruerngsa et al. 2000; Delp, 2004) including

the roundhouse kick itself (Demeere, 2009). To investigate this theory further an

analysis of the duration of the recovery phase (the point of impact to the point at

which the kicking leg returns to the floor) of the roundhouse kick needs to be

conducted to assess the extent at which the boxer is vulnerable.

Boey and Xie (2002) carried out a study investigating the turning kick

performance of Singapore National Taekwondo players. This study broke down

the kick into time taken between lifting the heel and max speed of hip (0.19

secs), max speed of the hip and max speed of knee (0.28), and max speed of

knee and max speed of foot (0.07 secs). However, “speed” and “velocity” were

used interchangeably in this study so it is unclear whether the distance between

foot and target was divided by distance (speed) or displacement (velocity).

Research carried out by Tang et al., (2007) on the kinematics of target effect

during roundhouse kick, the mean maximum velocity for the ankle, knee and hip

joint was 14.3m/s, 8.1m/s and 3.8m/s respectively. Pearson (1997) carried out a

similar study which investigated the kinetics and kinematics of the Taekwondo

turning kick where linear velocities of the ankle, knee and hip joint immediately

before impact were recorded at 12.1m/s, 2.11m/s and 0.69m/s respectively.

Similarly to Dorge et al., (2002), Sidthilaw (1996) also found that the linear

velocity of the ankle in the Muay Thai roundhouse kick reached the maximum

velocity (7.1 m/s) at 0.48 seconds prior to the point of impact. This reduction in

23

linear velocity of the ankle joint has been attributed to placing a greater

emphasis on accuracy (Pearson, 1997).

Only the kicking leg in Muay Thai has been observed (Sidthilaw, 1997),

however, the kicking leg and trunk (Kim et al., 2010), kicking leg and supporting

leg (Chang et al., 2007) and kicking leg and torso (Tsai et al., 2007) have been

examined in other studies in order to assess other contributions in the

Taekwondo roundhouse kick.

Literature is yet to include analysis of arm placement in martial arts kicks. Arm

placement in the Muay Thai roundhouse kick may not be taught to be placed in

the most desired or biomechanically advantageous position as in soccer or

rugby due to the combative nature of the sport i.e. the need to protect against

attacks from opponents. However, as stated by Demeere (2009) and Ruerngsa

et al. (2000), arm placement during the Muay Thai roundhouse kick is not

restricted to one position only and may be adapted to suit different situations

and desired outcomes. An investigation into arm placement during the Muay

Thai kick is required in order to ascertain whether or not one of these

adaptations result in a greater velocity kick.

2.7 Kicking Kinematics

The roundhouse kick appears to use the summation of speed theory in which

several segments of the body are involved in developing maximal speed. Welch

et al. (1995) briefly summarized this theory as ‘large base segments "passing"

momentum to smaller adjacent segments.’ The reactive impulse created by limb

movement can be quantified by either a direct measurement of impulse using

dynamography, or by an indirect measurement of the system's momentum

24

using kinematic analysis (Newton's Second Law) (Lees and Barton, 1996). But

the basic principle is that a system of segments moving at a certain velocity has

momentum. When a large base segment decelerates, the velocity of the

remaining system increases as it assumes the momentum lost by the base

segment. When one segment reaches its maximum angular velocity (zero

acceleration) during the midrange of its motion, it decelerates and transfers

angular momentum to the next adjacent distal segment in the chain (Welch et

al. 1995).

This sequence occurs, link by link, from large to small, from proximal to distal

until the end of the chain is reached (Kreighbaum and Barthels (1985),

therefore, the total speed is a sum of the total individual muscles added

together. Consequently, a large part of a Thai boxer’s mechanical performance

is derived from maximizing the kinetic link parameters.

Pearson (1997) studied this sequence in the Taekwondo turning kick and

concluded that practitioners should emphasise the sequential proximo-distal

sequencing, starting with flexion and abduction of the hip, and finishing with

knee extension. A pilot study by Sorensen (1996) shows this sequencing

occurring between the foot and knee in the martial arts high front kick. Sidthilaw

(1996) saw the same trend when investigating the kinematics of a roundhouse

kick using three-dimensional videography. Results showed that, in all subjects,

peak angular velocity at the hip preceded the peak angular velocity at the knee.

However, there are many other factors which contribute to creating maximal

velocity of a kick such as torso, arm and supporting leg positioning. Kim (1996)

found that hyperextension, abduction, and external rotation of the hip joint occur

prior to the kicking leg toe leaving the floor. Internal rotation and abduction of

25

the hip reached their peak during impact. Pearson (1997) stated that, when

analysing video data, the summation of speed sequence appears to begin with

trunk rotation.

2.8 Summary

Numerous studies have focused on the kinematics of kicking in field sports and

martial arts such as Taekwondo but a relatively small number have focused on

the kicking in Muay Thai. Kinematics is used to describe the study of motion

with no regard to its cause. A Muay Thai roundhouse kick involves all three

planes of motion which requires three dimensional analyses using digital

videography. A deterministic model can assist in the understanding of the

kinematic factors involved in a Muay Thai roundhouse kick and is a model that

determines the relationships between an outcome and the biomechanical

factors that produce it. Literature in soccer and rugby kicking has focused on

linear and angular velocity of the foot at ball contact. The measurement of

three-dimensional kinematics of the upper extremity has not received as much

scientific attention as that of the lower limb even the upper body also affects the

kicking performance.

Literature on martial arts kicks has focused on total duration, mean linear

velocity of joint segments and linear and angular final velocity of the kicking leg.

There is a lack of research analysing the torso and arms even though this may

affect kicking performance. The summation of speed is a theory in which

several segments of the body are involved in developing maximal speed and

may be evident in the Muay Thai roundhouse kick.

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Chapter 3 - Method

3.1 Participants

The subjects used for this study were 6 Muay Thai practitioners recruited from

‘Hybrid MMA’ gym, Plymouth. Subjects mean age was 24.1 (4.2) yrs with

between 6 months and 12 years’ experience. Subjects took part in 3 technical

training sessions a week and did not take part in any type of strength and

conditioning programme. One of the subjects had fought in a professional

competition and all others had competed in local interclub competitions. All

subjects were informed of the complete protocol along with all the risks involved

in partaking in such activities. They had sufficient opportunity to ask questions

before signing medical screening form and an informed consent form.

3.2 Equipment

Qualisys motion capture systems

Qualisys Track manager

6 cameras (Proreflex MCU 240, Gothenburg, Sweden)

Tripods (Manfrotto 161MK2B)

Muay Thai pads (Twins Special, Size L - 20x41x6cm)

Tanita scale (model BC 418 MA)

Vertical ruler

27

Tape measure

3.3 Protocol

Anthropometric data (weight , standing Height, sitting Height, Buttocks [Hip]

Circumference, upper Leg Length, knee Height, upper Arm Length) were

measured in accordance with the National Health and Nutrition Examination

Survey III (NHANES III, 1988) protocols (appendix 2).

To obtain 3-dimensional data the Qualisys motion capture system was utilised.

The set up consisted of 6 cameras (Proreflex MCU 240) operating at 60hz

mounted onto tripods (Manfrotto 161MK2B) roughly 2.5m tall but were adjusted

in order to capture the whole movement. Cameras one and four were placed

directly in front (camera one) and behind (camera four) the subject at a distance

of 4.3m and 3.6m respectively from the subjects nearest foot. Cameras two and

three were positioned to the left of the subject at a distance of 2.4m and 3.6m

respectively and cameras five and six were positioned in a similar fashion at a

distance of 2.3m and 3.8m respectively (figure 1). An area of –x—x-- was

marked out for the subjects to stand and perform the kick.

28

Figure 1 – Camera set up

Reflective markers were placed on the appropriate bony landmarks (right

shoulder, elbow wrist, left and right hips, lumbar spine, cervical spine (C7), right

knee and heel) of the subject to make analysis of the movement possible (figure

2). It should be noted that a marker was not placed on the toe as with most

other martial arts kick studies because the shank of the kicking leg should make

contact with the opponent – not the foot. Also, a marker was placed on the heel

so it was evident when the heel left the ground which makes analysis more

accurate. The subject then stood in the marked area and performed a kick to

ensure the cameras picked up all of the reflectors. Cameras were then adjusted

as need be and when satisfactory the Qualysis wand was then used to calibrate

the equipment. The cameras were then set at 60 frames per second for ease of

data analysis later on.

Figure 2 -

29

Subjects were bare-foot and wore Muay Thai shorts and a vest to perform the

kick. A warm up typical of a Muay Thai session was performed by the subject

consisting of dynamic stretching, prehab exercises and ‘fire up’ drills exercises

was performed by each subject to help prevent injury and prepare the individual

for the kick (appendix 1). The subject stood on a mat to perform the kick in an

attempt to replicate training and, to an extent, fighting conditions as some

friction is required in order to pivot on the ball of the foot of the standing leg

while still remaining balanced. Thai pads were held by a trainer for the subject

to kick. The distance these pads were held away from the subject was at the

subjects’ discretion (Pearson, 1997) as this distance will vary from fighter to

fighter due to height, limb length, stance and fighting style. The subject then

performed one maximal roundhouse kick.

Joint angles, linear velocity of all landmarks previously mentioned were then

analysed using Qualysis track manager. Angular velocity of the pelvis was also

analysed. The distance between the foot of the subject and the target was

measured from the ankle joint to the rear Thai pad as the shin should make

contact with the opponent in a real match – not the foot. This data was then

opened in Microsoft Excel and mad into graphs for analysis.

3.4 Data Analysis

Linear velocity and angular velocity was calculated via Qualisys track manager

and analysed in Microsoft in Excel. Pearson’s correlation co-efficient was

implemented to determine correlation between each of the kinematic and

anthropological variables. Results were considered statistically significant if the

30

‘p’ value was less than 0.05 (P ˂ 0.05). All data was analysed using SPSS

version 19.0.

Chapter Four – Results

For ease of analysis the kick has been broken down into 3 phases; phase 1 is

defined as the moment the heel lifts off of the floor (heel off) to the maximum

linear velocity of the hip. Phase 2 is defined as the point of maximum linear

velocity of the hip to maximum linear velocity of the knee. Phase 3 is defined as

the point of maximum linear velocity of the knee to maximum linear velocity of

the ankle.

4.1

Table 1 - Final Linear Velocities of the Joints of the Kicking Leg

subject Hip Knee Heel

m/s m/s m/s

Mean (±S.D.) 1.1(±0.4) 2.6(±1.3) 13.6(±2.3)

maximum 1.6 3.7 16.7

31

minimum 0.7 0.3 10.9

Mean final velocities for all joints of the kicking leg in table 1 show that the most

distal joint (Heel) was travelling at the greatest velocity at the moment before

impact (13.6m/s [±2.3]), followed by the more proximal joints (knee) (2.6m/s

[±1.3]) and then the hip (1.1 [±0.4]).

4.2

Table 2 - Total Duration of Each Phase of the Kick

Subject

PHASE 1 - Lifting heel -

max Velocity of hip (sec)

PHASE 2 - Max Velocity of Hip - Max Velocity of

Knee (sec)

PHASE 3 - Max velocity of Knee - Max Velocity of Heel (sec)

Total Duration (sec)

Mean (±) 0.03(±0.03) 0.15(±0.05) 0.28(0.12) 0.35(0.07)

Maximum 0.08 0.23 0.43 0.42

Minimum 0.00 0.10 0.13 0.27

Table 2 shows that phase 3 of the kick took the longest duration (0.28s [0.12]),

followed by phase 2 (0.15 [±0.05]) and then phase 1 (0.03 [±0.03]).

4.3

32

Figure 2 – Average Linear Velocities of the Kicking Leg

Figure 2 shows time taken to perform the kick expressed as a percentage is

displayed along the horizontal axis. Linear velocity is measured in metres per

second and is displayed along the vertical axis. Each phase of the kick is

highlighted as blue shading and is labelled either phase 1, phase 2 or phase 3.

Standard deviation is displayed via the error bars which are coloured in

accordance with the line colour of the joint velocity being displayed. The starting

velocity of the knee and ankle both precede the hip, although, during the third

phase of the kick the velocity of the Heel does increase rapidly as the knee

decelerates which suggests that the proximo-distal segment sequencing is

present. Another characteristic of figure 3 is that the knee and hip joints actually

increase in velocity during the last 10 and 15% after steadily decreasing since

the beginning of phase two of the kick.

0.0

2.0

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ear

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m/s

)

Time (%)

Average Linear Velocities of the Kicking Leg

Linear Velocity ofHip

Linear Velocity ofKnee

Linear Velocity ofHeel

PHASE 1 PHASE 2 PHASE 3

33

4.4

Figure 3 – Mean Joint Contributions of the Kicking Leg

Figure 3 shows joint velocity contributions of the kicking leg are expressed as a

percentage of total kick velocity in Figure 4. The maximum linear velocity at

each joint was calculated as a percentage of the linear final velocity at the heel

and is displayed along the vertical axis. Names of the joints are given along the

horizontal axis. The hip contributes 22% of the final heel velocity, the knee 31%

and the heel 49%.

0

5

10

15

20

25

30

35

40

45

50

Hip Knee Heel

Join

t Li

ne

ar V

elo

city

(%

)

Joint

Mean Joint Contributions of the Kicking Leg

Hip Knee

Heel

34

4.5

Figure 4 – Average Linear Velocities at the Joints of the Right Arm

Time taken to perform the kick expressed as a percentage is displayed along

the horizontal axis in figure 4. Linear velocity is measured in metres per second

and is displayed along the vertical axis. Each phase of the kick is highlighted as

blue shading and is labelled either phase 1, phase 2 or phase 3. Phase 2 shows

0.0

1.0

2.0

3.0

4.0

5.0

6.0

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ear

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)

Time (%)

Average Linear Velocities at the Joints of the Right Arm

Linear Velocity ofthe RightShoulder

Linear Velocity ofthe Right Elbow

Linear Velocity ofthe Right Wrist

PHASE 1 PHASE 2 PHASE 3

35

the greatest velocity in all joints in the right arm and phase 3 shows a gradual

decrease in all joints. The graph does not demonstrate the summation of speed.

4.6

Table 3 – Correlations of the Kinematic Variables

Height

Thigh

Length

Shank

Length

Maximum

Hip

Velocity

Maximum

Knee

Velocity

Final

heel

Velocity

Height Correlation 1 .887* .973** .570 .858* .959**

Significance

.018 .001 .238 .029 .003

N 6 6 6 6 6 6

Thigh

Length

Correlation .887* 1 .821* .370 .825* .920**

Significance .018

.045 .470 .043 .009

N 6 6 6 6 6 6

Shank

Length

Correlation .973** .821* 1 .697 .892* .954**

Significance .001 .045

.124 .017 .003

N 6 6 6 6 6 6

Maximum

Hip

Velocity

Correlation .570 .370 .697 1 .595 .588

Significance .238 .470 .124

.213 .220

N 6 6 6 6 6 6

Maximum

Knee

Velocity

Correlation .858* .825* .892* .595 1 .962**

Significance .029 .043 .017 .213

.002

N 6 6 6 6 6 6

Final heel

Velocity

Correlation .959** .920** .954** .588 .962** 1

Significance .522 .003 .009 .003 .220 .002

N 6 6 6 6 6 6

36

Statistical significance was calculated using a 2-tailed T-test and was deemed

to be statistically significant if the result was ˂ 0.05 (*) or ˂ 0.01 (**). All data

was analysed using SPSS. A significant and positive correlation exists between

thigh length (r=0.920, P=0.009), shank length (r=0.954, P=0.003), subject

height (r=0.959, P=0.003) and final heel velocity.

4.7

Figure 5 – Angular Velocity at the Pelvis

-300.0

-200.0

-100.0

0.0

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gula

r V

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city

(D

eg/

s)

Time (%)

Angular Velocity at the Pelvis

Average angular Velocityat Pelvis (YZ)

Average Angular Velocityat Pelvis (XZ)

Average Angular Velocityat Pelvis (XY)

PHASE 1 PHASE 2 PHASE 3

37

Angular Velocity at the hips along the YZ, XZ, XY axis (see Figure 8) is shown

in figure 5. Time taken to perform the kick expressed as a percentage is

displayed along the horizontal axis. Angular velocity is expressed as degrees

per second and is displayed along the Vertical axis. Angular velocities are

erratic throughout the movement and fluctuate at each stage. Phase 3 shows a

sharp increase in angular velocity in the YZ axis while the XZ and XY show a

steady decrease.

4.8

38

Figure 6 – Angles at the Pelvis During Kick

Angles at the hip joint throughout the entire kick along the YZ, XZ, XY axis (see

Figure 8) are shown in figure 6. Time taken to perform the kick expressed as a

percentage is displayed along the horizontal axis. Angular velocity is expressed

as degrees per second and is displayed along the Vertical axis. YZ pelvis angle

decreases smoothly throughout phase 1 and 2 before steadily increasing in

phase 3. XZ and XY pelvis angles steadily increase during phases 1 and 2, XY

continues to increase before plateauing and decreasing while XZ gradually

decreases.

Chapter 5 - Discussion

The main findings in the present study are that the speed of the heel during the

3rd phase of the kick appears to be the most influential factor in producing a

high velocity roundhouse kick and thus shank length is the most advantageous

-10.0

0.0

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gle

(d

eg)

Time (%)

Angles at Pelvis During Kick

Pelvis Angle(XY)

Pelvis angle(XZ)

Pelvis Angle(YZ)

39

anthropometric measure to possess. These findings are consistent with the

hypothesis that thigh length and shank length will be important factors in

determining the velocity of a roundhouse kick. The speed of the heel is

dependent on two things; the speed of the knee and the length of the shank.

Seeing as the linear speed of the knee joint is the sum of the linear speed of the

hip joint and the product of the angular speed at the hip and the length of the

thigh, it seems advantageous for Thai boxers to possess long thighs and long

shanks. However, due to the summation of speed theory, shank length appears

to be more pertinent to a high velocity kick due to each distal segment

assuming the proximal segment’s velocity.

In order to depict the crucial factors that contribute to a high velocity

roundhouse kick, a deterministic model was developed. This model will

establish the mechanical factors that determine the velocity of a roundhouse

kick.

Velocity of the Roundhouse

Kick

Displacement (shank to

target)

Length of Lower Limbs

Time (shank to

target)

Speed of heel

40

Velocity is speed in a given direction. In this case, the velocity is being analysed

as opposed to speed as the fighter needs to make contact with the target

(opponent) as quickly as possible so velocity gives a better indication of

efficiency. The displacement between shank and target depends on the lower

limb length of the subject. A fighter should utilize the space between himself

and his opponent efficiently to enable him to stay at a safe distance from his

opponent i.e. out of punching and kicking range but where he doesn’t have to

move an unnecessary distance to be able to attack. The time taken for the

shank to reach the target depends on the speed at which the heel travels from

the floor to the target.

The speed of the heel immediately before impact is the product of the knee joint

linear speed and shank length. The linear speed at the knee is the function of

Speed of heel

Speed of Knee

Speed of HipLength of

ThighAngular Speed

at Hip

Phase 1 Change in

Angular Speed

Phase 2 Change in

Angular Speed

Length of Shank

41

the linear speed at the hip and the sum of the thigh length and hip angular

speed.

42

Figure 7 – Deterministic Model of the Roundhouse Kick

Velocity of the Roundhouse kick

Displacement (shank → target)

Length of lower limbs

Time

(shank → target)

speed of heel

speed of knee

speed of hip

length of thighangular speed of

hip

phase 1 change in angular speed

phase 2 change in angular speed

length of shank

43

The importance of shank length is evident when analysing correlations between

the different kinematic variables and final heel velocity. A significant and

positive correlation exists between thigh length (r=0.647, P=0.009), shank

length (r=0.984, P=0.003) and final heel velocity in the present study which is

consistent with the hypothesis. This could be attributed to the summation of

speed theory as the limb rotating around the axis (joint) has more time to gain

momentum which is then passed on to the next distal segment. A stronger

correlation exists between shank length and final heel velocity as, in theory, the

speed accumulated by the 3rd phase would be greater than in the 1st or 2nd

phase so therefore, the segment (shank) rotating around the axis (knee joint)

should have the potential to gather more momentum. This is in accordance with

Skoufas et al. (2004) who also found that the most distal segment in the chain

had the most influence on throwing velocity.

Generally speaking, when a segment is rotating, the longer the segment, the

higher the linear velocity developed on the distal to the centre of rotation side.

When applying this principle to a Muay Thai roundhouse kick, athletes with

longer segments should develop higher throwing velocity of the ball provided

that the angular velocities around the participating to the motion joints are not

lower when compared to the angular velocities of an athlete with shorter

segments (Skoufas et al., 2004)

Maximum hip velocity positively correlated (r=0.595) with maximum knee

velocity. This correlation was not significant (P=0.213); although it may suggest

that the large base segment (hip) could possibly have transferred momentum to

the smaller adjacent segment (knee). The knee, however, demonstrates this

sequence to a much larger extent with a significant (P=0.002) and almost

44

perfect positive correlation (r=0.962) between maximum knee velocity and final

heel velocity. This data, once again, suggests that there was a bigger

contribution from the hip flexors and knee extensors during the kick and little hip

extensor/torso rotator activation. Figure 4 displays this evidence more clearly;

the hip joint accounts for 22% of the total velocity during the kick, the knee

accounts for 31%, and the heel 49%. This demonstrates the relatively low

contribution of the hip. However, no known studies have dissected the

roundhouse kick in this way which makes comparisons impossible.

A significant (P=0.003) and positive correlation (r=0.959) was found between

final heel velocity and subject height which are similar to findings by Van den

Tillaar & Ettema (2004), Vila et al. (2009), Zapartidis et al. (2009) and Skoufas

et al. (2004) who recorded significant and positive correlations between ball

velocity and anthropometric variables such as body mass index (BMI), body

mass, lean body mass and height in throwing tests. In the present study, subject

height was measured but seated height and limb length was not. Therefore, this

finding cannot be attributed to either leg length or torso length. Skoufas et al.

(2004) found that arm length was less important than hand width and hand

length when producing a high velocity throw. If torso length positively correlated

with final heel velocity then this may have suggested that the proximal-distal

segment sequencing began with torso rotation. However, this seems unlikely

given that maximum hip velocity does not significantly correlate with maximum

knee velocity or final heel velocity.

Identifying the desired anthropometric variables required for Muay Thai

performance could lead to the discovery of potential performers and the

recognition of current participants with the potential to become an elite Thai

45

boxer. Talent detection refers to the discovery of potential performers who are

currently not involved in the sport in question while talent identification (TID) is

the process of recognising individuals currently participating in the sport with the

potential to become elite (Mohamed et al. 2009).

Height and length of limbs can largely effect sports performance (Hahn, 1990)

and, based on the evidence presented in the present study, could also influence

Muay Thai performance. Therefore, comparing height and limb lengths of

athletes to literature can assist in the TID process. For instance, Elite Australian

rowers have been reported as a tall group with proportionally long limb length

compared with the general population (Hahn, 1990).

TID and development has become a vital component of many sport

programmes (Falk et al., 2004) and, if introduced to Muay Thai, may be useful

by measuring thigh length and shank length in order to assess potential within

the sport. No literature currently exists on TID in Muay Thai. The introduction of

TID in Muay Thai would seem advantageous due to its recent raise in profile

and the role it currently plays in combat sports, as previously mentioned.

Table 2 gives the time taken for each phase of the kick to take place. A mean

time of 0.03 seconds was recorded for the lifting of the heel to reach maximum

velocity of the hip, 0.15 seconds for the maximum velocity of the hip to reach

maximum velocity of the knee and 0.28 seconds for maximum velocity of the

knee to reach maximum velocity of the hip. The total duration of the kick was

recorded at a mean value of 0.35 seconds which is similar to those found by

Boey and Xie (2002) who recorded times of 0.33 seconds which is surprising as

this study used more experienced athletes from the Singapore National

Taekwondo squad. The total duration of the kick in this study higher than that

46

found in Falco et al., (2009) study of non-elite athletes (0.23 secs) and much

lower than Tang et al., (2007) (0.6 seconds). The total duration of the kick

recorded in this study (0.35 seconds) is 0.01 seconds slower than the reaction

time needed to start a counterattack movement or to avoid the attack (Vieten et

al., 2007). This indicates that the opponent may have already begun a block,

counter attack or an evasive move in order to avoid the strike before the

roundhouse kick has landed. The recovery phase of the roundhouse kick needs

to be conducted to investigate this theory in full but from the evidence presented

it would seem that the mean total duration of the roundhouse kick performed in

this study would be too slow to be deemed an effective strike in a Muay Thai

fight.

Time taken from heel off until maximum hip velocity was much quicker in the

present study when compared to Boey and Xie, (2002) study (0.19 seconds),

while the second and third phase in the previously mentioned study (0.07, 0.07)

are much faster than in the present study (0.15, 0.28). This evidence suggests

that the fairly inexperienced Muay Thai practitioners used in this study didn’t

place much emphasis on the initial hip drive and, instead, focused more on the

knee flexion and then knee extension phases. Since the large base segments

pass momentum to smaller adjacent segments so that the smaller segment to

transfers momentum to the next adjacent distal segment in the chain, the

athletes in the present study are missing out on an opportunity to maximise

segment velocity to pas onto the next distal segment. The Singapore National

Taekwondo squad athletes used in the previously mentioned study took longer

to gain maximum velocity in order to transfer this momentum to the next two

47

phases of the kick and achieve a greater velocity at the moment before impact

(18m/s) than in the present study (13.6m/s).

The reason for the poor hip drive during phase 1 may be due to differences in

neural adaptation. Neural adaptation refers to changes in the nervous control of

the muscle (Adamson et al. (2008). Subject 6 (6 months experience) and

subject 1 (12 years’ experience) displayed a large difference in initial hip

velocity (1802m/s and 2851m/s respectively). The more experienced athletes

may be able to recruit more motor units and increased motor unit firing through

repetition; it has been suggested by Van Cutsem et al. (1998) that strength

training may increase motor unit firing frequency and thereby increase the

potential for force development. However, none of the participants in the

present study took part in a strength and conditioning programme at the time of

testing.

In contrast to the hypothesis, the average linear velocities presented in figure 3

do not strictly represent the summation of speed theory to full extent as seen in

other martial arts kick studies by Pearson (1997), Sidthilaw (1997) and

Sorensen et al., (1996). In these studies the maximum velocity of the hip

precedes the maximum velocity of the knee and the maximum velocity of the

knee precedes the maximum velocity of the ankle for every subject. However, in

the present study the starting velocity of the knee and heel both precede the

hip, although, during the third phase of the kick the velocity of the heel does

increase rapidly as the knee decelerates which suggests that the proximo-distal

segment sequencing is present.

Joris et al. (1985) found it most likely that proximal segment deceleration (in this

case, the knee) could be explained by Newton's third law, which states that a

48

more proximal segment's action on a more distal segment will cause an equal

but opposite directed reaction on the more proximal segment. Sorenson et al.

(1996) suggests that active deceleration of the thigh is likely to be performed by

the gluteus maximus or the hamstring muscles. It was therefore of particular

interest to determine the exact temporal activity of these muscles during the

movement.

Another characteristic of figure 3 which differs from the aforementioned studies

is that the knee and hip joints actually increase in velocity during the last 10 and

15% after steadily decreasing since the beginning of phase two of the kick. This

is an interesting finding as this has not been seen previously in martial arts kick

studies. The Muay Thai practitioners taking part in this study may be performing

a re-extension the of the hip and knee to help produce maximal velocity before

impact due to the fact that the initial hip extension during phase one was not

emphasised and, as a consequence, they didn’t achieve the velocity potential to

pass on to the next distal segment.

This increase in joint velocity in the latter stages of the kick is in contrast to the

results found by Sidthilaw (1997). In this study joint velocity actually decreases

by around 4m/s during the final 0.06 seconds of the movement on average. This

finding has been attributed to the subjects placing a greater emphasis on

maintaining accuracy (Pearson, 1997; Lees et al., 2010) and a protective

mechanism of the hamstrings which prevents the knee joint from reaching full

extension at full velocity (Lees et al., 2009) to avoid hamstring injury. However,

EMG readings would need to be analysed to explore this theory further.

Final heel velocity was recorded at 13.6m/s. This finding is consistent with the

hypothesis that the greatest linear velocity at any joint will be seen at the heel

49

immediately before impact. This data is substantially higher than that recorded

by Sidthilaw (1996) for the Thai boxing middle roundhouse kick which was

recorded at 7.1 m/s. As previously mentioned, all Thai boxing subjects in the

aforementioned study recorded their maximum ankle velocities approximately

0.10s before impact. The mean ankle heel velocities found in this study are

similar to those found in other martial arts kick studies - 14.3m/s (Tang et al.,

2007), 12.1m/s (Pearson, 1997) and significantly lower than that found in

studies by Kong et al., (2000) who recorded values of 18.83m/s and O’Sullivan

et al., (2009) who recorded values of 17.66m/s. It should be noted that the

majority of these studies recorded the final linear velocity of the foot/ankle and

not the heel.

Figure 5 shows the average linear velocities of the right shoulder, elbow and

wrist during the kick. Modeling of movement of the wrist and elbow is relatively

simple, since both can be represented as two-degrees-of-freedom joints.

However, the shoulder joint complex is an articulation that defies simple

kinematic description. It consists of two separate articulations, with

scapulothoracic and glenohumeral components (Rab, 2002).

The data suggests that the summation of forces theory is not evident during the

arm swing in the present study. Ruerngsa et al. (2000) states that because the

roundhouse kick relies on the rotation of the body it is easy for boxers to lose

their balance while attempting to deliver the kick. A common way to

compensate for this is for a boxer to drop his rear arm backwards and

downwards (extending the shoulder and elbow joints) in order to stay balanced.

Rapid acceleration of the wrist is evident during the hip and knee drive (phase 1

and 2) but rapidly decreases during phase 2. The large changes in linear

50

velocity at the wrist and the relatively low changes seen at the elbow and

shoulder joints suggests that the arm movement is predominated by extension

of the elbow. Although the ‘recovery’ phase of the kick wasn’t analysed in the

present study, not only does the arm-leg synchronisation appear to be an

important factor in recovering from impact but could also affect kicking velocity.

Ashby and Heegaard (2002) found increases of 12.7% in the take-off velocity of

standing long jumps due to arm motion. However, the standing long jump only

takes place in two planes of motion. It was concluded that the additional

momentum imparted to the system by swinging the arms may contribute to the

increase in take-off velocity. So, if swinging the arms in the same plane and

direction of force can add additional momentum then one would assume that

swinging the arms in the opposite direction would decrease the momentum

carried across each phase.

This counter productivity can be seen in figure 5 as the linear velocities of the

right shoulder, elbow and wrist begin to decrease after phase 1 of the kick. This

decrease in velocity could be attributed to the R.O.M. at the shoulder joint; the

decrease in shoulder, elbow and wrist velocity begins just after phase one of the

kick so from this point onwards the lack of flexibility in the shoulder joint appears

to be pulling the torso and lower body in the opposite direction which could be

decreasing the velocity in the heel. However, accurate determination of

scapular position is difficult without skeletal pins, time-consuming palpation, or

complex imaging techniques that are potentially invasive, expensive and

impractical in most research settings (Rab, 2002).

Demeere (2009) and Ruerngsa et al. (2000) agree that swinging the right arm

backwards and downwards at the same time helps stabilise the kick by giving

51

counterbalance for the hip turn. Demeere (2009) also lists other advantages to

this technique such as protection of the chin by pulling the rear shoulder into the

jaw and the fact that this is the easiest and most natural movement when

performing the kick. However, this publication by Demeere (2009) offers an

alternate right arm position for the Muay Thai roundhouse kick; extending the

arm towards the face of the opponent. One of advantages of this method is that

if the opponent’s eyes are covered it will make it harder for him to see and to

counter strike, giving a window of opportunity to land the kick. Another

advantage is that the arm can be used to punch at the same time and can also

disguise the kick and, finally, the arm can be placed diagonally across the

opponent’s body to smother his arms or use it to sweep the opponents legs

from under him with the kick.

Ruerngsa et al. (2000) also advocates the use of this ‘arms up’ method and

concludes that the roundhouse kick may be performed with both fists held to the

front in order to protect the face. Using this alternate method may decrease kick

velocity to a lesser extent due to the kicker being able to increase momentum

using the arm. However, the precise mechanisms by which arm swing can

cause greater kick velocity are still unclear and these methods need to be

compared and analysed fully in order to ascertain the advantages and

disadvantages associated with each technique. This analysis should include a

recovery phase as Ruengsa et al., (2000) states that the reason the arm is

dropped is because it is easy for boxers to lose their balance while attempting

to deliver the kick. Therefore, analysis of the recovery phase would show

whether dropping the arm is an effective technique to use during a real fight.

52

The left arm was not analysed in the present study. Ruengsa et al., (2000)

states that the left (lead) arm move in front of the face in a high guard position

that places the elbow near jaw level and the hand practically above (but in

contact with) the head. This creates a more solid barrier of defence against a

counter attack. The shoulder of the arm that is dropped protects the jaw on the

other side as previously mentioned. Demeere (2009) also approves of this left

hand placement but also advocates the option of bringing the hand across the

body and in front of the face in order to protect the chin from straight punches to

a greater extent.

Shan and Westerhoff (2005) studied full body kinematics in soccer and found

that the upper body demonstrates some important characteristics of technique.

The non-kicking side arm was found to abduct and horizontally extend before

support foot contact and then adduct and horizontally flex to ball contact and

has been frequently attributed to the maintenance of balance (Lees et al.,

2010). If this is the natural placement of the left arm then Thai boxers are

somewhat restricted when placing the left arm on the head and may have to

balance themselves in different ways such as throwing the right arm down and

back as previously mentioned.

53

Figure 8 – A print screen of the XY, YZ and XZ axis.

Rotational movement can be explained by means of the following 3 axes (figure

8): the longitudinal (Z) axis (axis of rotation passing from feet to head through

the centre of gravity, the lateral (X) axis (axis of rotation passing from right to

left through the system’s centre of gravity), and the frontal (Y) axis (axis of

rotation passing from front to back through the system’s centre of gravity). With

the definition of the 3 principal axes, a description of combined movements may

be possible (Schack, 2003).

During phase 1 the pelvis shows little increase in angular movement (2.6°) in

the XY axis with an increase from 11.1°-13.7°. This angular movement could be

attributed to the initial abduction of the hip of the kicking leg and the forward

movement created by the triple extensors (extensors of the hip, knee and ankle)

of the supporting leg. During this phase the right hip is beginning to rotate

54

around the support or “anchor” leg via the XY axes. The angular velocity

recorded at the pelvis along these axes began at 13.1°/s at heel off and

increased by 10.2°/s before descending to 19.3°/s at the end of the phase. This

fluctuation of relatively low angular velocity may be attributed to irregular motor

unit recruitment and/or rate coding (Adamson et al. (2008) which may be

caused by fact that some participants were inexperienced practitioners.

Voluntary movements are planned, executed, and stored in memory directly by

means of representations of their anticipated perceptual effects. Cognitive

concepts seem to play a crucial role in movement control and representations

create a link between the central goal and the biomechanical organization of the

movement (Schack, 2003). Rotational movements such as the roundhouse kick

demand a highly defined perceptual-cognitive organization and a mastering of

many degrees of freedom. By using an expert-beginner paradigm, differences in

the structure and organization of knowledge between experts and beginners in

physical activity were found (Thomas and Thomas, 1994). It was concluded that

experts have far superior skills, declarative knowledge, and procedural

knowledge in performance; the latter is the one which has the greatest potential

for manipulation.

A sharper increase (10.9°) was seen in the XZ axis where the hip of the kicking

leg is elevated along the vertical (Z) axis via the triple extension mechanism. In

order for the right hip to rotate around the support leg it must first be elevated

along the Z axis via the triple extension mechanism described earlier with the

addition of the hip abductors again, accounting for the movement along the X

axis. Angular velocities along the XZ axis followed the same trends as XY axis

with a fluctuation of relatively low velocity.

55

The Linear and vertical (YZ) angle decrease (-8.3°) of the pelvis during phase 1

of the kick could also be attributed to triple extension – but mainly the plantar

flexion of the ankle which is causing the pelvis to move in a linear direction as

well as in a vertical direction. Angular velocity begins at -127.4°/s and fluctuates

slightly in the same fashion as in the XZ and XY axis.

A steady and even increase in the XY and XZ planes is seen during phase 2.

The majority of the angular motion of the pelvis along the XY axis is achieved

during phase 2 and the angle at the XZ axis actually reaches its peak in the last

frame of the phase. This steady increase in pelvic angle is coupled with a

wavering decrease in angular velocity.

Phase 2 shows a steep but gradual angle decrease (58.6°) in the YZ axis. It is

during phase 2 that the majority of this angular change occurs in the YZ axis.

The athlete should only have the ball of his supporting foot in contact with the

ground in order to use this as a “pivot” (Ruerngsa et al., 2000) in which to

externally rotate the left hip in preparation for the later phases. It appears to be

this triple extension that is causing this pivot and the angular change in the YZ

(linear/lateral) axes. It seems reasonable to assume that the pivot takes place in

order for this change in angle to occur in the YZ axis considering that the

majority of the angular change for the XY and XZ also occurs in this phase.

Therefore, this pivot is making the rotation of the pelvis around the anchor leg

easier by having less mass in contact with the ground and thus, less friction. A

gradual increase in angular velocity of 42.9°/sec is seen before a slight

decrease of 4.7°/sec during the last 13% of the phase.

Pelvic angular change along the XY axis during phase 3 sees a much less

steep increase (10.1°) and eventually a decrease (3.3°) during the last 15% of

56

the kick. Phase 2 saw the angle along the XZ axis peak and then begin a

gradual decrease (17.3°) during phase 3. Angular velocities along the XY and

XZ axes fluctuate but are consistent with one another in that, an increase

occurs, followed by a decrease, another increase before ending with a gradual

decrease during the last 20% of the kick. This evidence suggests that there is

less emphasis being placed on hip abduction and triple extension to rotate the

pelvis, and when this information is considered along with the average linear

velocities of the ankle, there is evidence that the emphasis is has shifted to

knee extension to maximise ankle velocity immediately before impact. Pedzich

(2006) states that the use of hips allows an athlete to shorten the distance

between him and his opponent. It is assumed that this means that when a Thai

boxer increases the angle through the XY axis he is able to reach a greater

distance with the kick. This could be advantageous when avoiding a counter

attack.

The pelvic angle along the YZ axis decreases (7.8°) in phase 3 before

beginning a rapid increase (26.2°) during the final 25% of the kick. Angular

velocity along these axes rapidly increase for the first 8% of the phase before

decreasing slightly for 5%; this may suggest that one or all of the triple

extensors is flexing and then re-extending during this phase. The reason for this

may be to increase linear velocity of the heel immediately before impact. In

contrast to the hypothesis, YZ angular velocity, as with the YZ angle, then

rapidly increases to its peak value during the 3rd phase before decreasing

during the last 10% of the phase. This suggests that the majority of the activity

seen in the YZ axis occurs during the last 25% of the kick.

57

An interesting finding when comparing linear with angular change and angular

velocities is that the majority of the angular change and angular velocity at the

pelvis occurs during phase 2 where ankle linear velocity is relatively low. During

phase 3 the linear velocity of the ankle increases sharply while the XY and XZ

angular change and angular velocity at the pelvis decrease.

In future, studies should use professional athletes who have all competed at a

similar level.

Chapter 6 - Conclusion

In line with the hypothesis, thigh length and shank length were found to be

influential in the velocity of the Muay Thai roundhouse kick and significantly and

positively correlated with final heel velocity. In contrast to the hypothesis, the

summation of speed theory was not evident in the present study as maximum

velocity of the hip did not precede the maximum velocity of the knee and the

maximum velocity of the knee did not precede the maximum velocity of the heel

for any subject. Average knee linear velocity was higher than hip and heel linear

velocity throughout phases 1 and 2 which suggests hip flexion dominates during

these phases and not torso rotation or knee extension as in some other studies.

The maximum linear velocity at any joint immediately before impact was found

in the heel which was in accordance with the hypothesis.

This data suggests that athletes with greater thigh length, and more importantly,

shank length may have a mechanical advantage in martial arts kicking over

participants with shorter measures and may wish to begin training in Muay Thai

58

or another striking art. This finding may also be advantageous for talent

identification scouts.

Muay Thai boxers may wish to employ the following technical practical

applications:

Phase 1 - Begin the kick by emphasising hip flexion to increase maximum knee

linear velocity over phases one and two.

Phase 2 - Attempt to achieve maximal knee flexion during phase two in order to

achieve maximal heel final linear velocity.

Phase 3 - Emphasise maximal angular velocity and pelvis rotation during phase

3. Also, emphasise hip flexion and knee extension immediately before impact.

Note: Athletes may also wish to utilise the “arms up” method throughout the

kick.

Strength and Conditioning practical applications:

1. A strength training programme may be included in a Thai boxer’s

regime in order to potentially increase motor unit firing frequency and

thereby increase the potential for force development.

2. Specifically, hip flexion strength should be addressed; this movement

initiates the kick and is often overlooked in strength and conditioning

programs.

3. Open and closed kinetic chain exercises should be included in

programmes.

59

References

Adamson, M., MacQuaide, N., Helgerud, J., Hoff, J., Johan, O. (2008) Unilateral

arm strength training improves contralateral peak force and rate of force

development, Eur J Appl Physiol (2008) 103:553–559

Ashby, B. M., Heegaard, J. H. (2002) Role of arm motion in the standing long

jump, Journal of Biomechanics 35, 1631–1637

Ball, K. (2008): Biomechanical considerations of distance kicking in Australian

Rules football, Sports Biomechanics, 7:1, 10-23

Bartlett, R., (2007) Introduction to Sports Biomechanics Analysing Human

Movement Patterns, Second edition, Taylor & Francis Group, Oxon

Bezodis, N., Trewartha, G., Wilson, C., Irwin, G. (2007) Contributions of the

non-kicking-side arm to rugby place-kicking technique, Sports Biomechanics,

6:2, 171-186

Boey, L. W., Xie, W. (2002). Experimental investigation of turning kick

performance of Singapore National Taekwondo players. Proceedings of the

20th International Symposium on Biomechanics in Sport. Caceres, Spain, 302-

305.

Chang, W-G, Chang, J-S, Tang, W-T (2007), Kinematic and Kinetic Analysis of

Lower Limbs in Taekwondo Double Jump Roundhouse Kick During Landing,

60

Institute of Coaching Science, National College of Physical Education and

Sports, Taiwan.

Chapman, Arthur. E, 2008, Biomehanical Analysis of Fundamental Human

Movement, USA, Human Kinetics

Chow, J. W., Knudson, D. V. (2011): Use of deterministic models in sports and

exercise biomechanics research, Sports Biomechanics, 10:3, 219-233

Delp, C. (2004) Muay Thai: Advanced Kickboxing Techniques, 1st ed. USA:

Frog, Ltd.

Demeere, W. (2009) [Online]: The Leg Kick: Your guide to using the shin kick in

the ring or the cage, accessed 06.05.2012, available at:

http://users.telenet.be/wim.demeere/The-Leg-Kick-A-guide-for-Devastating-

Low-Kicks-in-MMA-and-muay-Thai.pdf

Dorge, H.C., Andersen, T.B., Sorensen, H. and Simonsen, E.B. (2002)

Biomechanical differences in soccer kicking with the preferred and the non-

preferred leg. Journal of Sports Sciences 20, 293-299.

Falco, C. A., Alvarez, O. B. C., Castillo, I. C., Estevan, I. A., Martos, J. D.,

Mugarra, F. D., Iradi, A. E. (2009) Influence of the distance in a roundhouse

kick’s execution time and impact force in Taekwondo, Journal of Biomechanics

42, 242–248

Falk, B., Lidor, R., Lander, Y., Lang, B. (2004): Talent identification and early

development of elite water-polo players: a 2-year follow-up study, Journal of

Sports Sciences, 22:4, 347-355

Gartland, S., Malik, M. H. A., Lovell, M. E. (2001) Injury and injury rates in Muay

Thai kick boxing, Br J Sports Med, 35:308–313

Glazier, P. S. and Robins M. T. (2012) Comment on “Use of deterministic

models in sports and exercise biomechanics research” by Chow and Knudson

(2011), Sports Biomechanics, 11:1, 120-122

Glazier, P. S., Paradisis, G. P., Cooper, S-M (2000) Anthropometric and

kinematic influences on release speed in men’ s fast-medium bowling, Journal

of Sports Sciences, 2000, 18, 1013-1021

Hahn, A. (1990) (cited in Hoare and Warr, 2009) Identifcation and selection of

talent in Australian rowing. Excel, 6, 5-11

Ham, D. J., Knez, W. L., Young, W. B. (2007) A Deterministic Model of the

Vertical Jump: Implications for Training, Journal of Strength and Conditioning

Research, 21(3), 967-972

61

Hamill, J. and Knutzen, K. M. (2009): Biomechanical Basis of Human

Movement, Lippincott Williams & Wilkins,

Harun, H., Xiong, S. J., Pendidikan, F. (2012) The Symmetry In Kinematics

Between The Dominant And Non-Dominant Legs In Taekwondo Turning Kick

Universiti Teknologi, Malaysia (online) accessed 09.01.2012, unpublished,

http://eprints.utm.my/10720/1/The_Symmetry_In_Kinematics_Between_The_Do

minant_And_Non.pdf

Hay, J.G. and Reid, G. (1982) (cited in Lees, 2002) Anatomy, Mechanics and

Human Motion. Englewood Cliþs, NJ: Prentice-Hall.

Hay, J. G. (1984) [cited in Chow and Knudson (2011)] The development of

deterministic models for qualitative analysis. In R. Shapiro, and J. R. Marett

(Eds.), Proceedings of the Second National Symposium on Teaching

Kinesiology and Biomechanics in Sports (pp. 71–83). Colorado Springs, CO:

United States Olympic Committee.

Hay, J. G., and Reid, J. G. (1988a) Anatomy, mechanics and human motion.

Englewood Cliff, NJ: Prentice-Hall.

Hay, J. G., and Reid, J. G. (1988b) [cited in Ham et al., 2007] Anatomy.

Mechanics, and Human Motion, Englewood Cliffs. NJ: Prentice Hall

Hoare, D. G. and Warr, C. R. (2000): Talent identification and women's soccer:

An Australian experience, Journal of Sports Sciences, 18:9, 751-758

Jaric, S. (2003) Role of body size in the relation between muscle strength and

movement performance. Exercise Sport Sci Rev 31:8–12

Jöris, H.J., van Muyen, A.J., van Ingen Schenau, G.J. and Kemper, H.C. (1985)

(cited in Sorenson et al., 1996), Force, velocity and energy flow during the

overarm throw in female handball players. Journal of Biomechanics, 18, 409-

414

Kreighbaum, E. & Barthels, K.M. (1985) (cited in Kim, 1996). Biomechanics: A

qualitative approach for studying human movement. Minneapolis, MN: Burgess

Publishing Company

Kim, J. W., Kwon, M. S., Yenuga, S. S., Kwon, Y. H., (2010) The effects of

target distance on pivot hip, trunk, pelvis, and kicking leg kinematics in

Taekwondo roundhouse kicks, Sports Biomechanics, 9(2): 98–114

Kim, Y., (1996) Effect of Practice on Pattern Changes: Roundhouse Kick in

Taekwondo, Master of Science, Korea: Korea Advanced Institute of Science &

Technology

62

Kong, P-W., Luk, T-C. and Hong, Y. (2000) Difference Between Taekwondo

Roundhouse Kick Executed by the Front and Back Leg – A Biomechanical

Study, The Chinese University of Hong Kong, Hong Kong SAR, 268-272

Lees, A and Barton, G (1996): The interpretation of relative momentum data to

assess the contribution of the free limbs to the generation of vertical velocity in

sports activities, Journal of Sports Sciences, 14:6, 503-511

Lees, A. (2002): Technique analysis in sports: a critical review, Journal of

Sports Sciences, 20:10, 813-828

Lees, A., and Nolan, L. (1998). The biomechanics of soccer: A review. Journal

of Sports Sciences, 16, 211-234.

Lees, A., Steward, I., Rahnama, N. and Barton, G. (2009) Lower limb function in

the maximal instep kick in soccer, Contemporary Sport, Leisure and

Ergonomics, Taylor and Francis, 148-160

Lees, T. Asai, T. B. Andersen, H. Nunome and T. Sterzing (2010): The

biomechanics of kicking in soccer: A review, Journal of Sports Sciences, 28:8,

805-817

McGinnis, P. M. (2005), Biomechanics of sport and exercise 2nd edition, p48

Mohamed, H., Vaeyens, R., Matthys, S., Multael, M., Lefevre, J., Lenoir, M. and

Philippaerts, R. (2009): Anthropometric and performance measures for the

development of a talent detection and identification model in youth handball,

Journal of Sports Sciences, 27:3, 257-266

Muay Thai Online (2012): Muay Thai Judging. [ONLINE] Available at:

http://www.muaythaionline.org/features/muaythaijudging.html. [Accessed 03

March 12].

Nhanes III (1998) National Health and Nutrition Examination Survey III, Body

Measurements (Anthropometry), (ONLINE) accessed 26.02.2012

Nunome, H., IkegamI, Y., Kozakai, R., Apriantono, T., Sano, S. (2006)

Segmental dynamics of soccer instep kicking with the preferred and non-

preferred leg, Journal of Sports Sciences, 24:05, 529-541

O’Sullivan, D., Chung, C., Lee, K., Kim, E., Kang S., Kim, T. and Shin, I. (2009)

Measurement and comparison of Taekwondo and Yongmudo turning kick

impact force for two target heights. Journal of Sports Science and Medicine 8,

13-16

Pearson, J. N., (1997). Kinematics and Kinetics of the Taekwondo-Do Turning

Kick. Bachelor of Science, New Zealand: University of Otago

63

Pedzich, W., Mastalerz, A., Urbanik, C. (2006) The comparison of the dynamics

of selected leg strokes in taekwondo WTF, Acta of Bioengineering and

Biomechanics Vol. 8, No. 1,

Pieter, F. and Pieter (1995), speed and force in selected Taekwondo

techniques, Biology of Sport v.12 (4), p. 257-266, Accessed 08.03.2012 (online)

http://books.google.co.uk/books?hl=en&lr=&id=cRp91zZJHLIC&oi=fnd&pg=PA2

57&dq=+Reaction+time+in+Taekwondo&ots=Wsm6XnSimZ&sig=3eS4jkSKlbljZ

Cuyx7EbiVkiFyE#v=onepage&q=Reaction%20time%20in%20Taekwondo&f=fal

se

Portus, M. R., Sinclair, P. J., Burke, S. T., Moore, D.J.A., and Farhart, P.J.

(2000): cricket fast bowling performance and technique and the influence of

selected physical factors during an 8-over spell, Journal of Sports Sciences,

18:12, 999-1011

Pozo, J., Bastien, G., Dierick, F. (2011) Execution time, kinetics, and kinematics

of the mae-geri kick: Comparison of national and international standard karate

athletes, Journal of Sports Sciences, 29:14, 1553-1561

Rab, G., Petuskey, K., Bagley, A. (2002) A method for determination of upper

extremity kinematics, Gait and Posture 15, 113–119

Ruerngsa, Y., Charuad, K. K. and Cartmell, J. (2000) Muay Thai: The Art of

Fighting (online), accessed 06.04.2012, available at:

http://www.singto.co.uk/Techniques/artoffightingebook.pdf

Schack, T. (2003): The relationship between motor representation and

biomechanical parameters in complex movements: Towards an integrative

perspective of movement science, European Journal of Sport Science, 3:2, 1-13

Scurr, J. and Hall, B. (2009) The effects of approach angle on penalty kicking

accuracy and kick kinematics with recreational soccer players, Journal of Sports

Science and Medicine (2009) 8, 230-234

Serina, E.R., and Lieu, D.K. (1992) (cited in Harun, 2012) Thoracic injury

potential of basic competition taekwondo kicks. Journal of Biomechanics,

24(10), 951-960

Shan, G. and Westerhoff, P. (2005): Soccer, Sports Biomechanics, 4:1, 59-72

Sidthilaw, S, 1996. Kinetic and Kinematic Analysis of Thai Boxing Roundhouse

Kicks. Ph.D.. Oregon State: Oregon State University

Skoufas, D, & Katzamanidis, C., Hatzikotoylas, K., Bebetsos, G., & Patikas, D.

(2004). The relationship between the anthropometric variables and the throwing

performance in handball.

64

S⊘rensen, H., Zacho, M., Simonsen, E. B., Dyhre‐Poulsen, P., Klausen, K.

(1996): Dynamicsof the martial arts high front kick, Journal of Sports Sciences,

14:6, 483-495

Stockill, N.P. and Bartlett, R.M. (1994) (cited in Glazier et al., 2000) An

investigation into the important determinants of ball release speed in junior and

senior international fast bowlers. Journal of Sports Sciences, 12, 177-178

Stockill, N.P. and Bartlett, R.M. (1996). Possible errors in measurement of

shoulder alignment using 3-D cinematography. In Proceedings of the XIVth

International Symposium on Biomechanics in Sports (edited by J.M.C.S.

Abrantes), pp. 209± 212. Portugal: Edi‡ï es FMH.

Tang W.T, Chang J.S and Nien Y.H. (2007). “The Kinematics of Target Effect

During Roundhouse Kick in Elite Taekwondo Athletes.” Journal of

Biomechanics. 40(S2), XXI ISB Congress 59

Thomas, K. T., Thomas, J. R. (1994): Developing expertise in sport: The

relation of knowledge and performance. International Journal of Sport

Psychology, Vol 25(3), 295-312

Tsai, Y. J., Huang, C. F., Gu, G. H. (2007) The kinematic Analysis of Spin-Whip

Kick of Taekwondo in Elite Athletes, Poster Session 1/Sport. 14:45-15:45

Van Cutsem M, Duchateau J, Hainaut K (1998) (cited in Adamson et al., 2008):

Changes in single motor unit behaviour contribute to the increase in contraction

speed after dynamic training in humans. J Physiol 513:295–305

Van den Tillaar, R., and Ettema, G. (2004). Effect of body size and gender in

overarm throwing performance. European Journal of Applied Physiology, 91,

413–418.

Vieten, M., Scholz, M., Kilani, H., Kohloeffel, M. (2007) Reaction time in

Taekwondo. In: Proceedings of the 25th International Symposium on

Biomechanics in Sport. Ouro Preto, Brazil

Vila, H., Ferragut, C., Argudo, F..M., Abraldes, J. A., Rodriguez, N., & Alacid, F.

(2009). Relationship between anthropometric parameters and throwing velocity

in water polo players. Journal of Human Sport and Exercise, 4, 57–68.

Welch, C. M., Banks, S. A., Cook, F. F., Draovitch, P., (1995) Hitting a Baseball:

A Biomechanical Description, Journal of Orthopaedic and Sports Physical

Therapy, 22: 5

Zapartidis, I., Skoufas, D., Vareltzis, I., Christodoulidis, T.,Toganidis, T., &

Kororos, P. (2009). Factors influencing ball throwing velocity in young female

handball players. Open Sport Medicine Journal, 3, 39–43.

65

Appendix One – Warm up

2 mins - Jogging on spot

10x body weight squats

10x body weight walking lunges with torso twist

10x standing lateral lunges

10x A skip

10x Frankenstein walks

10x knee hug/quad stretch (hold each for 1 second)

10x walking glute med stretch

10x arm swing forward

10x arm swing back

30 secs – monster walks with thera band

10x glute bridges

10x (each leg) donkey kicks

66

Appendix Two - NHANES III anthropometric measures protocol

67

Appendix Three – Subject Data

Subject Age Exp. Standing Height

Mass Segment Lengths (m)

(yrs) (yrs) (m) (kg) shank thigh

1 27 12 190 87 0.45 0.44

2 23 8 185 80 0.44 0.44

3 19 0.5 180 78 0.43 0.4

4 20 0.8 175 86 0.42 0.4

5 26 9 186 82 0.44 0.44

6 30 1 183 79 0.43 0.43

68

Appendix Four – Subject one Pelvis Angles

NO_OF_FRAMES 19 NO_OF_CAMERAS 6 NO_OF_MARKERS 9458732 FREQUENCY 60 NO_OF_ANALOG 0 ANALOG_FREQUENCY 0 DESCRIPTION --

TIME_STAMP 2012-03-05, 13:48:57

DATA_INCLUDED Angle MARKER_NAMES Angle_YZ Angle_XZ Angle_XY

Frame Time Angle_YZ Angle_XZ Angle_XY

239 3.98333 78.408 3.299 11.1

240 4 75.286 8.903 11.619

241 4.01667 70.071 14.17 13.72

242 4.03333 64.092 19.035 16.902

243 4.05 57.397 24.381 20.261

244 4.06667 50.269 29.192 24.402

245 4.08333 41.787 34.388 29.13

246 4.1 32.651 39.546 33.431

247 4.11667 22.883 42.853 38.424

248 4.13333 12.274 44.824 42.584

249 4.15 5.5 43.468 46.005

250 4.16667 0.581 39.955 50.039

251 4.18333 -1.912 36.899 53.034

252 4.2 -2.299 35.155 54.747

253 4.21667 -0.61 34.892 55.102

254 4.23333 3.258 34.274 55.527

255 4.25 8.957 32.401 56.082

256 4.26667 15.031 30.241 55.494

257 4.28333 20.85 27.73 54.138

69

Appendix Five – Subject One Pelvis Angular Velocity

NO_OF_FRAMES 19 NO_OF_CAMERAS 6 NO_OF_MARKERS 9458732 FREQUENCY 60 NO_OF_ANALOG 0 ANALOG_FREQUENCY 0 DESCRIPTION --

TIME_STAMP 2012-03-05, 13:51:47

DATA_INCLUDED Angular Velocity MARKER_NAMES Angular_Velocity_YZ Angular_Velocity_XZ Angular_Velocity_XY

Frame Time Angular_Velocity_YZ Angular_Velocity_XZ Angular_Velocity_XY

239 3.98333 -82.641 331.111 -4.281

240 4 -250.103 326.127 78.596

241 4.01667 -335.811 303.981 158.487

242 4.03333 -380.212 306.315 196.21

243 4.05 -414.693 304.683 224.981

244 4.06667 -468.295 300.211 266.08

245 4.08333 -528.54 310.646 270.884

246 4.1 -567.129 253.97 278.81

247 4.11667 -611.317 158.315 274.595

248 4.13333 -521.486 18.452 227.433

249 4.15 -350.779 -146.044 223.627

250 4.16667 -222.377 -197.068 210.882

251 4.18333 -86.411 -144.004 141.247

252 4.2 39.069 -60.238 62.023

253 4.21667 166.718 -26.434 23.415

254 4.23333 287.006 -74.721 29.427

255 4.25 353.183 -120.996 -0.984

256 4.26667 356.802 -140.12 -58.321

257 4.28333 321.453 -146.242 -92.721

70

Appendix 6 – Subject one Linear Velocities of the Kicking Leg

NO_OF_FRAMES 19 NO_OF_CAMERAS 6 NO_OF_MARKERS 9458732 FREQUENCY 60 NO_OF_ANALOG 0 ANALOG_FREQUENCY 0 DESCRIPTION --

TIME_STAMP 2012-03-05,

13:38:55 DATA_INCLUDED Velocity MARKER_NAMES right knee_vel

right hip_vel right heel_vel

Frame Time (secs)

Time (%) right hip_vel right knee_vel

right heel_vel

1 0 0% 2851 5915 5069

2 0.02 6% 2737 6539 6711

3 0.03 11% 2581 7186 7089

4 0.05 17% 2512 7729 6091

5 0.07 22% 2478 8152 5198

6 0.08 28% 2395 8273 5562

7 0.10 33% 2232 8562 6075

8 0.12 39% 2019 8093 6423

9 0.13 44% 1629

6635

10 0.15 50% 1236 6478 6771

11 0.17 56% 907 5125 6856

12 0.18 61% 577 3293 7051

13 0.20 67% 621 1926 7453

14 0.22 72% 787

8159

15 0.23 78% 781 1928 9095

16 0.25 83% 770 2359 10568

17 0.27 89% 844 2656 12310

18 0.28 94% 819 2924 14250

19 0.30 100% 822 3451 16661

71

Appendix 7 - Subject one Linear Velocities of Right Arm

NO_OF_FRAMES 19 NO_OF_CAMERAS 6 NO_OF_MARKERS 9458732 FREQUENCY 60 NO_OF_ANALOG 0 ANALOG_FREQUENCY 0 DESCRIPTION --

TIME_STAMP 2012-03-05, 13:45:44

DATA_INCLUDED Velocity MARKER_NAMES right shoulder_vel right elbow_vel right wrist_vel

Frame Time

right shoulder_vel

right elbow_vel

right wrist_vel

239 3.98333 1831.583 1598.863 3759.841

240 4 2207.775 1256.927 4189.002

241 4.01667 1795.055 1269.576 4439.89

242 4.03333 1376.995 1275.987 4887.694

243 4.05 968.641 1302.729 5232.552

244 4.06667 1049.581 1274.078 5383.952

245 4.08333 1294.106 1462.459 5498.85

246 4.1 1507.508 2089.485 5570.281

247 4.11667 1468.708 2718.998 5695.967

248 4.13333 1168.804 2773.823 5801.18

249 4.15 761.205 2765.227 5749.334

250 4.16667 455.596 3055.15 5395.163

251 4.18333 312.381 3317.005 4934.164

252 4.2 310.354 3206.485 4403.062

253 4.21667 391.985 2817.95 3812.292

254 4.23333 536.635 2461.09 3289.05

255 4.25 631.55 2220.424 2880.674

256 4.26667 680.337 1873.187 2515.791

257 4.28333 680.084 1445.926 2063.517