Lower Extremity Kinematics of Stroke

Patients During Stair Ascending

Sujin Kim

The Graduate School

Yonsei University

Department of Rehabilitation Therapy

Lower Extremity Kinematics of Stroke

Patients During Stair Ascending

Sujin Kim

The Graduate School

Yonsei University

Department of Rehabilitation Therapy

Lower Extremity Kinematics of Stroke

Patients During Stair Ascending

A Masters Thesis

Submitted to the Department of Rehabilitation Therapy

and the Graduate School of Yonsei University

in partial fulfillment of the

requirements for the degree of

Master of Science

Sujin Kim

December 2008

This certifies that the masters thesis of Sujin Kim is approved.

Thesis Supervisor: Chunghwi Yi

Sanghyun Cho

Ohyun Kwon

The Graduate School

Yonsei University

December 2008

Acknowledgements

First of all, I want to express my gratitude to God. He always loves and leads me to

the right way, and I am very glad for his guidance and support that has enabled me to

finish this thesis. I want to share this pleasure with my lovely family—my father,

mother, and two sisters. They strongly supported and believed in me when I was

frustrated and fatigued. I can never thank them enough for their endless support.

I sincerely thank Professor Chunghwi Yi for his guidance and support. He has been

an excellent director of my research who always showed the gentle guidance of a

scholar, and has brought out my academic attitude to physical therapy. Professor

Sanghyun Cho gave me important advice related to technical issues and the writing

process. I also deeply thank Professor Ohyun Kwon for sincere advice that improved

the quality of this master’s thesis. He has showed me many new things and has

facilitated my passion for learning and pride in physiotherapy. I would also like to

thank Professor Hyeseon Jeon and Professor Sunghyun You for providing

encouragement and for helping to expand my knowledge.

I also express my sincerest thanks to my friends; especially Sunyoung Cho, who

encouraged me from the depth of her heart and shared with me throughout the study

period of my thesis, and Inho Oh, who gave endless help when I needed it and made

me feel secure. These people helped to make my life at graduate school very happy. I

also thank all the members of the Department of Rehabilitation Therapy, especially

my seniors, Wongyu Yoo and Minhee Kim, for their intellectual support and

guidance. I pray to God for their happiness. I also thank Mihee Ahn and Soyeon Park,

who gave me considerable advice and encouragement, and Sujin Hwang, who always

took care of me and was like a real sister to me.

- i -

Table of Contents

List of Figures ··························································································· iii

List of Tables ····························································································· iv

Abstract ······································································································· v

Introduction ································································································· 1

Method ········································································································ 5

1. Subjects ······························································································· 5

2. Instrumentation ···················································································· 8

2.1 Motion Analysis System ······························································· 8

2.2 Stair Configuration ······································································ 10

3. Step-by-Step Gait Pattern ·································································· 11

4. Procedure ··························································································· 12

5. Statistical Analysis ············································································ 13

Results ······································································································· 14

3.1 Spatio-temporal Parameters During Stair Ascending ····················· 14

3.1.1 Comparison Between the Leading and Trailing Limbs

for Affected and Unaffected Sides ·········································· 14

3.1.2 Comparison Between the Affected and Unaffected Sides

for Leading and Trailing Limbs ············································· 15

- ii -

3.2 Sagittal Kinematics of the Leading Limbs ······································ 16

3.3 Sagittal Kinematics of the Trailing Limbs ······································ 20

3.4 Comparison of the Movement Pattern ············································· 24

3.5 Body COM parameters ···································································· 27

Discussion ································································································· 28

Conclusion ································································································· 34

References ································································································· 35

Abstract in Korean ···················································································· 41

- iii -

List of Figures

Figure 1. Picture of the two steps ······························································· 10

Figure 2. Ascending cycle of the step-by-step stepping patterns

analyzed during stair ascending ················································· 11

Figure 3. Representative leading limb sagittal hip, knee, ankle

joint angles during stair ascending ············································· 19

Figure 4. Representative trailing limb sagittal hip, knee, ankle

joint angles during stair ascending ············································· 23

Figure 5. Movement pattern during stair ascending led by unaffected

side in a representative subject ··················································· 25

Figure 6. Movement pattern during stair ascending led by affected

side in a representative subject ··················································· 26

- iv -

List of Tables

Table 1. General characteristics of the subjects ·········································· 7

Table 2. Spatio-temporal comparison between the leading and

trailing limbs ··············································································· 14

Table 3. Spatio-temporal comparison between the affected and

unaffected sides ··········································································· 15

Table 4. Maximal and minimal joint angles of hip, knee, ankle of leading

limbs ···························································································· 17

Table 5. Hip, knee, ankle joint angles at initial heel contact, toe-off,

final heel contact of leading limbs ·············································· 17

Table 6. Maximal and minimal joint angles of hip, knee, ankle of trailing

limbs ···························································································· 21

Table 7. Hip, knee, ankle joint angles at initial heel contact, toe-off,

final heel contact of trailing limbs ·············································· 21

Table 8. COM displacement characteristics ············································· 27

- v -

ABSTRACT

Lower Extremity Kinematics of Stroke Patients

During Stair Ascending

Sujin Kim

Dept. of Rehabilitation Therapy

(Physical Therapy Major)

The Graduate School

Yonsei University

The purpose of the present study was to investigate differences in the joint angles

of the leading and trailing limb and center of mass motion parameters when stroke

patients ascent stair by the affected or unaffected side. Eleven stroke patients were

recruited and performed stair ascending by using a step-by-step gait pattern, three

trials with the unaffected foot leading onto the step and three trials with the affected

- vi -

foot leading at a self-selected comfortable speed. Sagittal plane angles of hip, knee,

and ankle and medio-lateral (M-L) COM displacement, peak M-L, anterior-posterior

(A-P), and vertical COM velocity were analyzed. Regardless of whether it was the

leading or trailing limb, the single limb support period of the unaffected side was

significantly longer than that of the affected side. In the leading limb, during the

initial and final contact of the leading limb on the stair, the hip, knee flexion angles

of the unaffected side was significantly higher than that of the affected side and

showed the delayed phase shift. In the trailing limb, the angle of ankle plantar flexion

of the unaffected side was significantly higher than that of the affected ankle when

toe off. It was also found that the M-L COM displacement, M-L and A-P peak COM

velocity when leading with the affected side was less than when leading with the

unaffected side. Different joint kinematics and COM parameters were adopted by

stroke patient to achieve completing but it was uncertain that these were whether

being associated with strategy to control movement and maintain balance that might

have enhanced safety during stair ascending or just revealing the limitation of stroke

patients. However, the use of step-by-step patterns could increase stability and

compensate for lower-limb weakness compared to using step-over-step patterns,

stroke patients who generally have a Brunnstrom level in the 4~5 stage or a high

activity level would especially benefit from this training method.

Key Words: Body center of mass, Leading limb, Lower limb kinematics, Stair

ascending, Stroke, Trailing limb.

- 1 -

Introduction

Stair climbing is a common activity that represents a frequently encountered

obstacle in daily living, and the ability to perform it efficiently affects the quality of

life (McFadyen, and Winter 1988; Nadeaua et al. 1997). Lowering and raising the

body mass while progressing forward to a step at a different level requires a large

range of joint motion, high joint moments, and increased duration and intensity of

muscle activity in the lower limbs (Andriacchi et al. 1980; Riener, Rabuffetti, and

Frigo 2002). Stair climbing is more difficult for those with impaired motor function,

balance problems, or reduced lower-limb function, and such difficulties are common

in stroke patients. Muscle weakness of the lower extremity, spasticity at the ankle,

and psychological factors of stroke patients can contribute to deficits in balance and

mobility performance following stroke and can cause these patients to fall (Eng et al.

2002; Fletcher, and Hirdes 2004; Ng, and Hui-Chan 2005). An understanding of the

kinematics of stair ascending is essential for preventing the associated injuries.

Previous studies on the mechanics and control of the lower extremities during stair

climbing have mainly analyzed the kinematics and kinetics of stair ascending and

descending by normal adults, or have been limited to comparisons in the young and

elderly at different inclinations (Mian et al. 2007a, 2007b; Riener, Rabuffetti, and

Frigo 2002). Some studies have also investigated the stair climbing of patients with

knee and hip impairment (Ewald et al. 1984; Ewald, Hsu, and Walker 1989),

- 2 -

amputees with artificial limbs (Sienko Thomas et al. 2002), and athletes with

deficiencies of the anterior cruciate ligament (Zaffagnini et al. 2006). However, the

literature contains no comprehensive analysis of the biomechanics of stair ascent by

patients with stroke. Understanding the biomechanics and pathomechanics of stair

climbing is important for therapists designing clinical examinations and management

plans for stroke patients based on scientific findings.

Most stroke patients show a dominant hemiplegic pattern in which the attack was

more severe on one side, which results in them relying more heavily on the

unaffected side during steady-state gait (Den Otter et al. 2007; Horvath, Tihanyi, and

Jozsef 2001). An asymmetric posture and compensatory movements such as trunk

lateral flexion or hip circumduction are commonly observed during stair ascending

(Ryerson, and Levit 1997). To recover stair-ambulation ability, patients with stroke

are told that the affected side should be placed after the unaffected side on each stair

during stair climbing (Senelick, Rossi, and Dougherty 1999). This is an effective

strategy for easily and safely ascending stairs, and conforms to the general rule of

strategies utilized during stair climbing. However, there has been controversy about

the treatment methods for reeducating stroke patients about stair ascending. Davies

(2000) suggested that patients should be taught to go up and down stairs normally

from the first attempt, while O'Sullivan, and Schmitz (2006) suggested that patients

with stroke should be told that the stronger lower extremity should always lead when

going up the stairs, and the weaker or involved limb should always lead when coming

down. Despite the existence of these controversies, no study has identified the

- 3 -

differences between these training methods or determined the most effective strategy

for stroke patients to ascend stairs. Collen, Baer, and Ashburn (2005) studied ranges

of linear displacements of the pelvis and feet in a small sample of stroke patients

when stepping up onto a step using the affected side or the unaffected side to lead.

Kim, and Eng (2003) studied the relationship between the isokinetic torque of

individual lower-limb muscle groups and stair climbing, and found correlations of

torque and function were similarly high for the unaffected and affected sides.

However, there are no published kinematics data for stroke patients with affected and

unaffected sides performing stair climbing. Reid et al. (2007) studied kinematics and

kinetics of healthy adults in the knee joint during alternating stair ambulation (step by

step), and suggested that the biomechanics differed between the leading and trailing

limbs because each limb performs different functions at different times. Some

previous studies have emphasized the importance of the different roles of the leading

and trailing limbs by investigating the joint kinematics and kinetics of either the

trailing or leading limb when obstacle crossing, and trunk and lower-limb kinematics

when using a quadricane during stair ascending (Chen, Lu, and Lin 2004; Hsue, and

Su 2008). However, no study has investigated the lower-limb kinematics of both the

leading and trailing limbs by directly comparing the affected and unaffected sides of

stroke patient under the same experimental protocol.

The purposes of the present study were to determine differences in the joint angles

of the leading and trailing limbs by comparing the affected and unaffected sides of

stroke patients during stair ascending and to determine the differences in center of

- 4 -

mass (COM) motion between when the affected or unaffected side leads during stair

ascent. The following questions were addressed: 1) What are the types of kinematics

gait patterns in sagittal profiles exhibited by patients with chronic stroke? 2) Are

there differences between affected sides and unaffected side movement strategies

during stair ascending? 3) What is the difference in body COM motion when stair

ascending with the affected or unaffected side?

- 5 -

Method

1. Subjects

Twelve stroke patients were recruited from a rehabilitation center ‘S’ and from the

rehabilitation department of a hospital ‘W’ in Wonju, Korea. Due to the loss of the

thigh marker, data on the angles of the lower limbs and the body COM were not

available for one subject. Complete data for all parameters were available for 11

subjects with stroke (8 males and 3 females). The mean age of patients was 47.5

years and mean time since the stroke was 26.4 months.

The inclusion criteria for patients were (1) a first unilateral ischemic or hemorrhagic

stroke, (2) being at least 6 months post stroke and able to walk 10 m and ascend stairs

without a gait aid or assistance, and (3) having a score greater than 20 on the Mini

Mental State Examination. The exclusion criteria were having (1) had more than one

stroke, and visual deficits, (2) severe impairment of cognitive functions that could

disturb cooperation, (3) a history of orthopedic or neurological disorder, and (4)

another disease that negatively influenced walking ability, or being unable to walk

independently. The characteristics of the subjects with stroke are listed in Table 1.

Prior to the study, all patients were clinically examined by an experienced physical

therapist to provide data for lower-limb motor selectivity using the Brunnstrom motor

stage, Dynamic Gait Index (DGI), modified Emory Functional Ambulatory Profile

- 6 -

(mEFAP), and Berg Balance Scale (BBS). Table 1 summarizes the results of these

clinical evaluations. All patients were free from hip contracture and preferred to lead

with the unaffected side during stair ascent. Each subject gave informed consent prior

to participating in the study.

- 7

-

11

10

9

8

7

6

5

4

3

2

1

Case no.

49

33

47

53

47

47

47

60

46

50

53

Age (years)

female

female

male

male

female

male

male

male

male

male

male

Gender

158

165

168

170

157

168

164

180

166

164

172

Height (㎝)

53

65

82

71

55

66

58

78

74

54

66

Weight (㎏)

ischemic

hemorrhagic

ischemic

ischemic

ischemic

ischemic

ischemic

ischemic

ischemic

ischemic

ischemic

Ischemia/ Hemorrhage

72

7

28

25

28

17

49

23

18

19

10

Month after stroke

right

right

left

right

left

right

right

right

right

right

right

Paretic side

17

17

8

8

15

8

7

8

10

8

8

DGIa

58

52

94

89

71

110

125

50

68

135

68

mEFAPb

aDGI: Dynamic Gait Index. bmEFAP: Modified Emory Functional Ambulation Profile. cBBS: Berg Balance Scale.

48

44

27

36

44

29

30

37

39

29

37

BBSc

Table 1. General characteristics of the subjects

- 8 -

2. Instrumentation

2.1 Motion Analysis System

Kinematics data and body COM parameters were collected using a VICON three-

dimensional motion analysis system. Data were collected at the Gait Analysis

Research Laboratory at Yonsei University. A VICON MX system (VICON MX

system, Oxford Metrics, U.K.) with six infrared cameras obtained kinematics data at

50 ㎐, which were processed by Nexus 1.3 software. Thirty-five spherical

retroreflective surface markers were placed on bony landmarks (either directly on the

skin or onto tight-fitting clothing) according to the guidelines of the VICON “plug-

in-gait” model marker set. Four markers were placed on the head (on a headband), on

the left and right temples, and on the left and right sides of the back of the head. Two

markers were placed on the spinal column (C7 and T10), one in the center of the right

scapula, and two on the sternum (sternum notch and xiphoid process). Markers on the

upper extremity were placed on the acromion process and lateral epicondyle of the

humerus, with two on the wrist and one on the head of third metacarpal bone. Four

markers were placed on the pelvis (ASISs and PSISs). Markers on the lower

extremity were placed on the lateral thigh, lateral epicondyle of the femur, lateral

side of the fibula, and lateral malleolus, with two on the foot (one on the back of the

heel and one distally on the second metatarsal bone). Static trials were recorded after

placing the above retroreflective markers. Anthropometric measurements included

- 9 -

the height, weight, leg length, and joint width of the knee and ankle. In addition, the

shoulder offset, width of the elbow and wrist, and hand thickness in the upper

extremity of each subject were entered into the “plug-in-gait” model used for the

calculation of kinematics data and body COM parameters. The location of the whole-

body COM was computed as the weighted sum of the COM of each body segment

from a 13-link biomechanical model. Each link was embedded with an orthogonal

coordinate system with the positive x-axis directed rightward, the positive y-axis

directed anteriorly, and the positive z-axis directed superiorly. A cardanic rotation in

the x-y-z direction was used to describe the rotational movements of each joint (Cole

et al. 1993). The medio-lateral (M-L) COM displacement, peak M-L COM velocity,

peak anterior-posterior (A-P) COM velocity, and peak vertical COM velocity were

measured in each trial. The A-P and vertical COM displacements on stairs were

constrained by the dimensions of the staircase, and so were not investigated. All

COM data were recorded during the stance phase because the A-P and M-L COM

velocities peak during the terminal stance and the vertical COM velocity peaks

during early single-limb support during the ascent. Peaks were extracted within the

same events or phases of the gait cycle, and they generally occurred during the stance

phase (Mian et al. 2007a).

- 10 -

2.2 Stair Configuration

The wooden staircase consisted of two steps, both of which had a rise of 18 ㎝

and a width of 56 ㎝. The first stair had a run of 28 ㎝, while the top step extended

to a run of 56 ㎝ in order to minimize the subjects’ fear of falling and to provide

space for subjects to turn around. To meet the minimum requirement for stair

climbing—not curb climbing, which consists of a single step and involves distinct

activity from stair climbing—our staircase comprised two steps (Figure 1). The

dimensions were similar to staircase designs used in previous studies (Christina, and

Cavanagh 2002).

Figure 1. Picture of the two steps.

- 11 -

3. Step-by-Step Gait Pattern

The stepping pattern started with the nontest limb in front of the step, followed by

the test limb onto the step, and then with both feet placed on the same step. The

ascending stride began with heel contact on the first stair and ended with heel contact

on the second stair. The limb that first moved onto the step to contact the first stair

was referred to as the leading limb, and the limb that stepped after the leading limb

was referred to as the trailing limb. The strides of the leading and trailing limbs were

defined using the acquired kinematics data, and were identified by the computer

operator using the stop-frame feature and frame-by-frame inspection of the displayed

stick figure. Figure 2 shows a schematic of the stepping procedure.

Figure 2. Ascending cycle of the step-by-step stepping patterns analyzed during stair

ascending. Solid line is for the leading limb, and dotted line is for the

trailing limb.

- 12 -

4. Procedure

After marker preparation, the subjects performed a step-by-step gait pattern for

ascending stair. Before experimental data were recorded, the subjects were allowed

to familiarize themselves with the staircase barefoot. They were assessed in three

trials with the unaffected side leading onto the step and in three trials with the

affected side leading at a self-selected comfortable speed. For the first three trials,

subjects were asked to step with the affected side onto the floor in front of the step

and then with the unaffected side onto the step, followed by the affected side onto the

step. The starting position of the subject was adjusted by the examiner so that one

step was taken with the tested limb before reaching the stair. All subjects were

instructed on the step-by-step gait pattern and advised not to attempt to ascend the

stair if they felt that it posed a risk to their safety. Two physical therapists stood

beside the subjects to assist them if necessary. To minimize fatigue, a chair was

provided in which the subjects rested for at least 1 minute between trials, and for 5

minutes when changing their leading limb. Mean values from three trials for the

affected and unaffected sides were used in the analysis of stair ascending.

- 13 -

5. Statistical Analysis

The results of the stair-ascending analysis were compared between the affected

and unaffected sides. Kolmogorov-Smirnov testing determined that most of the data

did not differ significantly from a normal distribution, and hence parametric analyses

were used. The paired t-test was used to compare differences in the spatiotemporal

parameters, kinematics data, and body COM parameters. Differences were

considered significant when the probability was lower than 0.05. SPSS version 12.0

(SPSS, Chicago, IL, U.S.A.) was used for statistical analyses.

- 14 -

Results

3.1 Spatio-temporal Parameters During Stair Ascending

3.1.1 Comparison Between the Leading and Trailing Limbs for Affected and

Unaffected Sides

The step length was longer (p=0.000) and the step width was lower (p=0.019) for

the leading limb than for the trailing limb when leading with the affected side (Table

2). The single-limb support period and step time were shorter (p=0.005) (p=0.002)

and the double-limb support period was longer for the leading limb than for the

trailing limb (p=0.003). When leading with the unaffected side, the leading-limb step

length remained significantly longer (p=0.000).

Table 2. Spatio-temporal comparison between the leading and trailing limbs

Affected side leads Unaffected side leads Parameters leading trailing leading trailing

Single support (％)b 20.08±6.22a 32.06±8.24* 34.07±9.92 23.15±5.38**

Double support (％) 49.50±9.89 44.15±8.63* 44.36±11.61 42.08±12.26

Step time (seconds) 1.60±0.53 1.17±0.26* 1.28±0.57 1.32±0.32

Normalized step length (step length/height) 0.20±0.02 0.02±0.02** 0.20±0.01 0.03±0.01**

Normalized step width (step width/ distance between ASIS)

0.87±0.19 0.92±0.20* 0.85±0.18 0.88±0.16

aMean±SD. brepresents duration by percent of gait cycle. * p<0.05, by paired t-test ** p<0.01,by paired t-test

- 15 -

3.1.2 Comparison Between the Affected and Unaffected Sides for Leading and

Trailing Limbs

The step length, step width, and double-limb support period did not differ

significantly between the affected and unaffected sides when leading with the

affected side. The step time was significantly shorter for affected side than for

unaffected side (p=0.045). Regardless of whether it was the leading or trailing limb,

the single-limb support period was significantly longer for the unaffected side than

for the affected side (p=0.002, p=0.005, respectively) (Table 3).

Table 3. Spatio-temporal comparison between affected and unaffected sides

Leading limb Trailing limb Parameters

affected unaffected affected unaffected Single support (％)b 20.08±6.22a 34.07±9.92** 23.15±5.38 32.06±8.24** Double support (％) 49.50±9.89 44.36±11.61 42.08±12.26 44.15±8.63 Step time (seconds) 1.60±0.53 1.28±0.57* 1.32±0.32 1.17±0.26

Normalized step length (step length/height) 0.20±0.02 0.20±0.01 0.03±0.01 0.02±0.02

Normalized step width (step width/ distance between ASIS)

0.87±0.19 0.85±0.18 0.88±0.16 0.92±0.20

aMean±SD. brepresents duration by percent of gait cycle. * p<0.05, by paired t-test ** p<0.01,by paired t-test

- 16 -

3.2 Sagittal Kinematics of the Leading Limbs

The maximum and minimum angles for sagittal-plane movements of the hip, knee,

and ankle joint of the leading limb are listed in Table 4. Joint angles at the initial heel

contact, toe-off, and final heel contact at the lower extremity are compared between

the affected and unaffected sides in Table 5. At the hip joint, the pattern of the

flexion angle was qualitatively similar for the affected and unaffected sides (Figure

3). The maximum and minimum angles did not differ significantly between the

affected and unaffected sides. However, during the initial and final contact of the

leading limb on the stair, the hip flexion was higher for the unaffected side than for

the affected side (p=0.005). At the knee joint, the maximal knee flexion angle was

higher when leading with the unaffected side (p=0.000). Also, in all events (initial

heel contact, toe-off, and final heel contact) the knee angles were significantly higher

for the unaffected side than for the affected side. At the ankle joint, a slightly plantar

flexion of the unaffected side was observed when leading with the unaffected side

(p=0.006), and a significant difference in the ankle joint angle was detected during

final heel contact (p=0.001).

- 17 -

Table 4. Maximal and minimal joint angles of hip, knee, ankle of leading limbs

Leading limbs Parameters

affected side unaffected side p

max. 58.57±6.84a 60.09±6.62 0.469 Hip joint.

min. 11.02±8.44 9.32±7.28 0.286

max. 66.94±13.73 92.90±8.81 0.000 Knee joint

min. 4.96±10.37 3.83±7.36 0.664

max. 20.91±4.97 23.51±5.20 0.121 Ankle joint

min. 2.53±6.12 -1.70±6.55 0.006 aMean±SD of the joint angle (degrees).

Table 5. Hip, knee, ankle joint angles at initial heel contact, toe-off, final heel contact

of leading limbs

Leading limb Phases affected side unaffected side p

initial heel contact 47.99±6.44a 54.49±6.54 0.001

toe-off 19.65±9.89 20.34±7.22 0.758 Hip Joint

final heel contact 49.65±6.21 54.92±5.44 0.004

initial heel contact 37.45±12.31 46.22±8.85 0.014

toe-off 15.03±10.11 23.13±8.55 0.018 Knee joint

final heel contact 38.68±11.92 50.34±7.38 0.000

initial heel contact 8.94±5.30 7.84±5.06 0.461

toe-off 4.93±5.97 3.83±6.54 0.431 Ankle joint

final heel contact 8.89±5.12 14.58±5.91 0.001 aMean±SD of the joint angle (degrees).

- 18 -

(C)

(B)

(A)

Leading limbs

- 19 -

Figure 3. Representative leading limb sagittal hip (A), knee (B), ankle (C) joint

angles during stair ascending. The profiles are intra-subject averages of

three trials for one subject. Solid line represents unaffected side and dotted

line represents affected side. OTO: opposite toe off, OHC: opposite heel

contact.

3.3 Sagittal Kinematics of the Trailing Limbs

Similar patterns of flexion angle were evident in the leading and trailing limbs.

The maximum and minimum angles for sagittal plane movements of the hip, knee,

and ankle joint of trailing limbs are listed in Table 6. Joint angles at the initial heel

contact, toe-off, and final heel contact at the lower extremity are compared between

the affected and unaffected sides in Table 7. The maximum knee flexion angle was

higher and the minimum ankle plantar flexion angle was lower for the unaffected side

- 20 -

than for the affected side (p=0.000, p=0.000). At the hip and knee joint, angle

patterns of the affected and unaffected sides during initial heel contact, toe-off, and

final heel contact were similar in the trailing and leading limbs (Figure 4). The only

difference between the leading and trailing limbs was found in the ankle joint. The

ankle toe-off angle for the trailing limb differed significantly between the affected

and unaffected sides. The angle of ankle plantar flexion was higher for the unaffected

side than for the affected side (p=0.000). In addition, the plantar flexion was

significantly higher in the unaffected side than in the affected side at toe-off

(p=0.009).

Trailing limbs Parameters

affected side unaffected side p

max. 30.55±13.03a 31.84±8.82 0.680 Hip joint.

min. -0.62±7.61 1.739±6.67 0.169

max. 33.40±13.42 54.88±10.49 0.000 Knee joint

min. -4.85±7.10 -2.53±4.28 0.189

max. 14.50±7.81 17.96±2.94 0.047 Ankle joint

min. -4.78±8.02 -19.32±6.12 0.000 aMean±SD of the joint angle (degrees).

- 21 -

Trailing limbs

Table 6. Maximal and minimal joint angles of hip, knee, ankle of trailing limbs

Table 7. Hip, knee, ankle joint angles at initial heel contact, toe-off, final heel contact

of trailing limbs

Trailing limb Phases affected side affected side

p

initial heel contact 15.56±7.94a 22.97±7.79 0.000

toe-off 5.00±7.42 4.72±7.09 0.853 Hip Joint

final heel contact 15.11±8.02 20.75±9.09 0.008

initial heel contact 7.60±8.02 16.25±7.34 0.001

toe-off 0.35±6.40 4.32±8.22 0.108 Knee joint

final heel contact 7.96±9.46 16.06±7.64 0.004

initial heel contact 5.88±5.13 8.55±4.12 0.054 toe-off -1.13±7.34 -8.76±9.11 0.009

Ankle joint

final heel contact 4.13±5.03 9.21±4.65 0.001 aMean±SD of the joint angle (degrees).

(A)

- 22 -

(B)

(C)

- 23 -

Figure 4. Representative trailing limb sagittal hip (A), knee (B), ankle (C) joint

angles during stair ascending. The profiles are intra-subject averages of

three trials for one subject. Solid line represents unaffected side and dotted

line represents affected side. OTO: opposite toe off, OHC: opposite heel

contact.

3.4 Comparison of the Movement Pattern

The maximum hip, knee flexion, and ankle dorsiflexion angles were lower in the

trailing limb than in the leading limb. The configurations between leading and

trailing limbs are shown in Figures 5 and 6, which illustrate the lower-extremity

movement in the sagittal plane during stair ascending.

- 24 -

(A)

(B)

- 25 -

Figure 5. Movement pattern during stair ascending led by unaffected side in a

representative subject. (A) is the leading limb, (B) is the trailing limb.

HJC: hip joint center, KJC: knee joint center, AJC: ankle joint center.

- 26 -

Figure 6. Movement pattern during stair ascending led by affected side in a

representative subject. (A) is the leading limb, (B) is the trailing limb.

HJC: hip joint center, KJC: knee joint center, AJC: ankle joint center.

(A)

(B)

- 27 -

3.5. Body COM parameters

The M-L COM displacement and the peak M-L, A-P, and vertical COM velocities

when leading with the affected and unaffected sides are compared in Table 8. The M-

L COM displacement was lower when leading with the affected side than when

leading with the unaffected side. The peak M-L and A-P COM velocities were

significantly higher when leading with the unaffected side than when leading with the

affected side. Conversely, the peak vertical COM velocity was significantly lower

when the affected leg was leading.

Table 8. COM displacement characteristics

Parameters Affected Unaffected p M-L COM displacement (㎝) 8.82±2.61a 10.02±2.25 0.023

M-L peak COM velocity (㎝/s) 13.35±4.03 14.79±3.85 0.039 A-P peak COM velocity (㎝/s) 28.86±6.91 33.76±9.00 0.007

vertical peak COM velocity (㎝/s) 36.11±7.78 32.84±5.57 0.037 aMean±SD. M-L: medio-lateral, A-P: anterior-posterior, COM: center of mass.

- 28 -

Discussion

This study has recorded kinematics data of individuals with stroke for the lower

extremities during stair ascending and has compared the patterns for leading and

trailing limbs on both the affected and unaffected sides. Our experiments involved

stepping on a staircase comprising two stairs since stroke patients are generally

unable to perform the reciprocal movements associated with multiple step-over-step

walking. Although stroke patients might adopt their own patterns or strategies, it is

still unclear whether treatment plans involving stair ascending should use the leading

limb on the unaffected or affected side, as well as what type of patterns—including

step-by-step and step-over-step patterns—are most effective for stroke patients.

It should be noted that both the rise and run of the stairs used in this study were

smaller than those of standard stairs. This would tend to underestimate rather than

overestimate the range of motion, maximal excursion, and compensations necessary

to perform stair ascent. In addition, the functional abilities of our stroke patients were

relatively high, so they could complete the stair ascending without falling or having

to perform severe compensational movements.

When our stroke patients led with their affected side, this limb demonstrated lower

hip and knee flexion at the initial and final heel contact and a smaller maximum knee

and ankle flexion angle compared to when the leading limb was unaffected. Figure 3

shows the patterns of the angles of leading limbs when climbing stairs, and reveals

- 29 -

that the magnitudes of angles were lower for the affected side when it was leading,

but the patterns were similar to those of the unaffected side. These features were

especially noticeable in the hip and knee joints, and this might be related to weakness

of the hip flexor muscle on the affected side, which is known to be a major

characteristic of stroke patients (Den Otter et al. 2006). When patients with stroke

lead with their affected side during stair ascending, decreased muscle power for hip

flexion reduces the hip flexion angle, which in turn decreases the knee flexion angle

because knee flexion is passive and affected by the movement of hip flexion during

swing (Gutierrez et al. 2003).

One interesting finding is that when patients led with their affected side, the angle

pattern was similar on the affected and unaffected sides, but with a phase shift. These

features might be indicative of attempts to stabilize during the loading response,

when the stance limb gradually accepts the body weight with little movement and

increases the extensor moment at the joints to increase their stiffness and stability

(Lin, Lu, and Hsu 2004). The patients in the present experiments were tested on a

step-by-step basis, and their leading limb might have played a pivotal role in lifting

up the body and the trailing limb (Reid et al. 2007). It is important for the leading

limb to maintain stability and safety while elevating the body and trailing limb during

stair ascending. However, the decreased hip and knee extensor muscle power of

stroke patients might make it more difficult to lift the body up and control balance.

Therefore, in these patients there would be a delay before the opposite foot pushes

off in order to adjust the alignment and maintain the stability of the leading limb for

- 30 -

balance. This study clearly found that stroke patients had a short single-limb support

period and longer double-limb support period and had a longer step time when they

led with the affected side to step up. After stability was maintained, the ankle of the

trailing limb on the unaffected side pushed off to propel the body forward and

upward (McFadyen, and Winter 1988). This is supported by our result that plantar

flexion of the unaffected side was considerably increased during the late support

phase. This is due to the insufficient hip and knee extensor power of the affected side

for lifting the body being compensated for with an increased ankle plantar flexion

angle of the unaffected side when ascending stairs with the leading affected side.

A reduction in the M-L COM displacement was observed when leading with the

affected side. This observation is similar to those of experiments where patients

stepped on a single step; the subjects with hemiplegia showed a greater range of

pelvic lateral displacement towards their unaffected side and less pelvic lateral

displacement on the affected side (Collen, Baer, and Ashburn 2005).

The decreased M-L COM displacement in stroke patients when they lead with the

affected side reflects their difficulty in maintaining dynamic stability in the frontal

plane (Said et al. 2008). Patients with stroke exhibit instability in the frontal plane

due to paralysis of the lower extremity muscles, especially the hip abductor muscle

that provides frontal plane stability during loading phase. They have difficulty

controlling dynamic weight shifts from the unaffected side to the affected side during

stair ascent, and they put less weight on their affected side due to this instability,

which would tend to prevent falls toward the affected side of the body (Diller, and

- 31 -

Weinberg 1970). Additionally, the peak M-L COM velocity was lower when leading

with the affected side than when leading with unaffected side, confirmed that stroke

patients are subject to biomechanical challenges when attempting to maintain balance

in the frontal plane.

The A-P COM velocity was significantly lower when our subjects with stroke led

with their affected side than when they led with their unaffected side. This might be

related to the reduced dorsiflexion angle and strength of the extensor muscle of the

leading limb (Kim, and Eng 2003), because a forward shift of the COM over the

leading limb is produced by ankle dorsiflexion and extension muscle activation of the

leading hip and knee during the stance phase of the leading limb (Charness 1985). In

our stroke patients the knee was slightly more extended on the affected side than on

the unaffected side during the single-limb support phase when the affected leg was

trailing. This extended knee would contribute to restricted ankle movement or

weakness of the knee extensor muscle. All of our subjects exhibited tightness in the

achilles tendon that might have decreased ankle dorsiflexion. Therefore, when

subjects ascending stairs lead with their affected side, restricted ankle dorsiflexion

might make forward shifting of the COM difficult, resulting in a reduction in the A-P

COM velocity.

We found that the joint kinematics and COM displacements and velocities

exhibited by stroke patients performing a stair climbing task vary with their physical

condition. However, it was uncertain whether these differences were due to the

adoption of a suitable strategy for controlling and maintaining balance that enhanced

- 32 -

safety during stair ascending, or merely reflected limitations of the stroke patients

associated with muscle weakness, sensory loss, balance impairment, and

psychological problems. Further investigations are necessary to elucidate these

relationships.

The findings of this study have implications in clinical practice. Patients with

stroke consistently demonstrate asymmetries in timing, with support times being

longer for an unaffected supporting leg than for an affected supporting leg. This

phenomenon has been well documented in the gait patterns of stroke patients during

level walking (Tokuno, and Eng 2006), and was also observed for stair ascending in

the present study. Treatment programs for rehabilitating stroke patients should

emphasize the performance of the affected side in order to reduce the asymmetry of

movement patterns (Laufer et al. 2000; Wall, and Turnbull 1986).

The results from this study suggest that overload of the unaffected side could be

reduced and active movement of the affected side could be facilitated during stair

ascent by using the affected side as the leading limb. This is because each limb has

its own positional role, with the leading limb moving much more to lift the body up,

while the trailing limb maintains stability by supporting the leading limb (McFadyen,

and Winter 1988; Reid et al. 2007). Therefore, training that involves leading with the

affected side during stair ascending would prevent the affected side in patients with

stroke from adapting into learned nonuse and protect the unaffected side from

overuse. The use of step-by-step patterns could increase stability and compensate for

lower-limb weakness compared to using step-over-step patterns by allowing for a

- 33 -

shorter and slower stride (Reid et al. 2007)—stroke patients who generally have a

Brunnstrom level in the 4~5 stage or a high activity level would especially benefit

from this training method. This would further help stroke patients in the recovery

phase to learn to negotiate stairs in a normal way.

- 34 -

Conclusion

This study assessed the kinematic data and body center of mass of individuals with

stroke for the lower extremities during stair ascending and has compared the patterns

of leading and trailing limbs on both the affected and unaffected side. The mean

single limb support period of the unaffected side was significantly longer than that of

the affected side regardless of whether it was the leading or trailing limb. In the

leading limb angles of the affected side was significantly lower than that of the

unaffected side and showed the delayed phase shift and M-L COM displacement, M-

L peak COM velocity, and A-P peak COM velocity when leading with the affected

side was less than when leading with the unaffected side. We suggest that this

adopted by stroke patient to achieve completing task that were most suitable for their

physical condition and encourage stroke patients generally had an Brunnstrom level

in 4~5 stage or had an high activity level would be trained during stair ascending by

leading their affected side for obtaining benefits.

- 35 -

References

Andriacchi TP, Andersson GB, Fermier RW, Stern D, and Galante JO. A study of

lower-limb mechanics during stair-climbing. J Bone Joint Surg Am.

1980;62(5):749-757.

Charness A. Stroke & Head Injury. Chicago: Aspen Publisher, 1985.

Chen HL, Lu TW, and Lin HC. Three dimensional kinematic analysis of stepping

over obstacles in young subjects. Biomedical Engineering. 2004;16(3):157-164.

Christina KA, and Cavanagh PR. Ground reaction forces and frictional demands

during stair descent: Effects of age and illumination. Gait Posture.

2002;15(2):153-158.

Cole GK, Nigg BM, Ronsky JL, and Yeadon MR. Application of the joint

coordinate system to three-dimensional joint attitude and movement

representation: A standardization proposal. J Biomech Eng. 1993;115(4A):344-349.

Collen FM, Baer GD, and Ashburn AM. Stepping onto a single step: A kinematic

study. Physiother Res Int. 2005;10(2):81-92.

- 36 -

Davies PM. Steps to Follow. The comprehensive treatment of patients with

hemiplegia. New York: Springer, 2000.

Den Otter AR, Geurts AC, Mulder T, and Duysens J. Gait recovery is not

associated with changes in the temporal patterning of muscle activity during

treadmill walking in patients with post-stroke hemiparesis. Clin Neurophysiol.

2006;117(1):4-15.

Den Otter AR, Geurts AC, Mulder T, and Duysens J. Abnormalities in the

temporal patterning of lower extremity muscle activity in hemiparetic gait. Gait

Posture. 2007;25(3):342-352.

Diller L, Weinberg J. Evidence for accident-prone behavior in hemiplegic patients.

Arch Phys Med Rehabil. 1970;51(6):358-363.

Eng JJ, Chu KS, Dawson AS, Kim CM, and Hepburn KE. Functional walk tests in

individuals with stroke: Relation to perceived exertion and myocardial exertion.

Stroke. 2002;33(3):756-761.

Ewald FC, Hsu HP, and Walker PS. Is kinematic total knee replacement better than

total hip replacement? Orthop Clin North Am. 1989;20(1):79-88.

- 37 -

Ewald FC, Jacobs MA, Miegel RE, Walker PS, Poss R, and Sledge CB. Kinematic

total knee replacement. J Bone Joint Surg Am. 1984;66(7):1032-1040.

Gutierrez EM, Bartonek A, Haglund-Akerlind Y, and Saraste H. Centre of mass

motion during gait in persons with myelomeningocele. Gait Posture.

2003;18(2):37-46.

Fletcher PC, and Hirdes JP. Restriction in activity associated with fear of falling

among community-based seniors using home care services. Age Ageing.

2004;33(3):273-279.

Horvath M, Tihanyi T, and Jozsef T. Kinematic and kinetic analsis of gait patterns

in hemiplegic patient. Physical Education and Sport. 2001;1(8):22-35.

Hsue BJ, and Su FC. Gait and kinematics of the trunk and lower extremities in

stair ascent using quadricane in healthy subjects. Gait Posture. 2008.

Kim CM, and Eng JJ. The relationship of lower-extremity muscle torque to

locomotor performance in people with stroke. Phys Ther. 2003;83(1):49-57.

- 38 -

Laufer Y, Dickstein R, Resnik S, and Marcovitz E. Weight-bearing shifts of

hemiparetic and healthy adults upon stepping on stairs of various heights. Clin

Rehabil. 2000;14(2):125-129.

Lin HC, Lu TW, and Hsu HC. Three dimensional analysis of kinematic and kinetic

coordination of the lower limb joints during stair ascent and descent. Biomedical

Engineering. 2004;16:101-108.

McFadyen BJ, and Winter DA. An integrated biomechanical analysis of normal

stair ascent and descent. J Biomech. 1988;21(9):733-744.

Mian OS, Thom JM, Narici MV, and Baltzopoulos V. Kinematics of stair descent

in young and older adults and the impact of exercise training. Gait Posture.

2007a;25(1):9-17.

Mian OS, Narici MV, Minetti AE, and Baltzopoulos V. Centre of mass motion

during stair negotiation in young and older men. Gait Posture. 2007b;26(3):463-

469.

Nadeaua S, Gravel D, Hcbertb LH, Arsenaulta AB, and Lepage CY. Gait study of

patients with patellofemoral pain syndrome. Gait Posture. 1997;5(1):21-27.

- 39 -

Ng SS, and Hui-Chan CW. The timed up & go test: its reliability and association

with lower-limb impairments and locomotor capacities in people with chronic

stroke. Arch Phys Med Rehabil. 2005;86(8):1641-1647.

O'Sullivan SB, and Schmitz TJ. Physical Rehabilitation, 5th ed. PA, Philadelphia:

F.A. Davis Company, 2006.

Reid SM, Lynn SK, Musselman RP, and Costigan PA. Knee biomechanics of

alternate stair ambulation patterns. Med Sci Sports Exerc. 2007;39(11):2005-2011.

Riener R, Rabuffetti M, and Frigo C. Stair ascent and descent at different

inclinations. Gait Posture. 2002;15(1):32-44.

Ryerson S, and Levit K. Functional Movement Reeducation: A contemporary

model for stroke rehabilitation. New York: Churchill Livingstone, 1997.

Said CM, Goldie PA, Patla AE, Culham E, Sparrow WA, and Morris ME. Balance

during obstacle crossing following stroke. Gait Posture. 2008;27(1):23-30.

Senelick RC, Rossi PW, and Dougherty K. Living With Stroke: A guide for

families. 2nd ed. Illinois: Contemporary publishing group, 1999.

- 40 -

Sienko Thomas S, Buckon CE, Jakobson-Huston S, Sussman MD, and Aiona MD.

Stair locomotion in children with spastic hemiplegia: The impact of three different

ankle foot orthosis (AFOs) configurations. Gait Posture. 2002;16(2):180-187.

Tokuno CD, and Eng JJ. Gait initiation is dependent on the function of the paretic

trailing limb in individuals with stroke. Gait Posture. 2006;24(4):424-428.

Wall JC, and Turnbull GI. Gait asymmetries in residual hemiplegia. Arch Phys

Med Rehabil. 1986;67(8):550-553.

Zaffagnini S, Bignozzi S, Martelli S, Imakiire N, Lopomo N, and Marcacci M.

New intraoperative protocol for kinematic evaluation of ACL reconstruction:

Preliminary results. Knee Surg Sports Traumatol Arthrosc. 2006;14(9):811-816.

- 41 -

국문 요약

편마비편마비편마비편마비 환자의환자의환자의환자의 계단계단계단계단 오르기오르기오르기오르기 동작동작동작동작 시시시시

하지의하지의하지의하지의 운동학적운동학적운동학적운동학적 분석분석분석분석

연세대학교 대학원

재활학과(물리치료학 전공)

김 수 진

본 연구에서는 11명의 만성 뇌졸중 환자가 계단을 오르는 동안 환측

다리로 먼저 올라 가는 경우와 건측 다리로 먼저 올라 가는 경우에 양쪽

다리의 운동형상학적(kinematics) 특성과 신체질량 중심 이동의 특성에

있어서 차이가 있는지를 알아보았다.

연구 대상자들은 건측 다리를 먼저 계단 위에 내디디며 환측 다리를

끌어올리는 과정을 세 번 반복하였고, 다음으로는 환측 다리를 계단 위에

내디디며 건측 다리를 끌어올리는 과정을 세 번 반복하였다. 환측과

건측을 비교하였을 때, 환측이 이끄는 다리이든 끌려가는 다리이든

- 42 -

상관없이 환측의 단하지 지지기간이 건측보다 짧았다. 이끄는 다리에

있어서 초기 접지기와 후기 접지기 때 환측의 고관절과 슬관절

굴곡각도가 환측이 건측보다 작았으며 각도 그래프의 패턴은 건측과

비슷한 양상을 보였으나 패턴이 뒤늦게 나타났다. 끌려가는 다리에 있어서

환측의 족관절 저측굴곡 각도가 건측보다 유의하게 작았다.

좌우 신체질량 중심 편위는 건측 다리를 먼저 내디디며 계단을 오를

때가 환측 다리를 먼저 내디디며 계단 오를 때보다 컸으며, 좌우, 전후

신체질량 중심 이동의 최고 속도는 건측 다리를 먼저 내디디며 계단

오르기를 할 때 더 빨랐다.

이상의 결과는 뇌졸중 환자가 계단 오르기를 성공적으로 하기 위해

자신들의 신체 상태에 따라 다른 전략을 사용하는 것을 보여주며,

Brunnstrom 4~5단계의 환자들이나 높은 활동 단계의 움직임이 가능한

환자들은 환측을 먼저 내디디며 계단을 올라가도록 훈련하는 것이

효과적일 것으로 사료된다.

핵심되는 말: 계단 오리기, 끌려가는 다리, 뇌졸중, 신체질량 중심, 이끄는

다리, 하지의 운동 형상학.