The Back Squat a Proposed Assessment

8/20/2019 The Back Squat a Proposed Assessment

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The Back Squat:

A Proposed Assessmentof Functional Deficits andTechnical Factors ThatLimit PerformanceGregory D. Myer, PhD, CSCS*D,1,2,3,4 Adam M. Kushner, BS, CSCS,1 Jensen L. Brent, BS, CSCS,5

Brad J. Schoenfeld, PhD, CSCS, FNSCA,6 Jason Hugentobler, PT, DPT, CSCS,1,7

Rhodri S. Lloyd, PhD, CSCS*D,8 Al Vermeil, MS, RSCC*E,9,10 Donald A. Chu, PhD, PT, ATC, CSCS, FNSCA,10,11,12

Jason Harbin, MS,13 and Stuart M. McGill, PhD141Division of Sports Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio; 2Department ofPediatrics and Orthopaedic Surgery, University of Cincinnati, Cincinnati, Ohio; 3Sports Health & Performance Institute,The Ohio State University, Columbus, Ohio; 4The Micheli Center for Sports Injury Prevention, Waltham,Massachusetts; 5The Academy of Sports Performance, Cincinnati, Ohio; 6Department of Health Sciences, CUNYLehman College, Bronx, New York; 7Division of Occupational Therapy and Physical Therapy, Cincinnati Children’sHospital Medical Center, Cincinnati, Ohio; 8Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, Wales,United Kingdom; 9Titleist Performance Institute, Oceanside, California; 10Athercare Fitness and Rehabilitation Clinic,Alameda, California; 11Rocky Mountain University of Health Professions, Provo, Utah; 12Ohlone College, Newark,

California;

13

BEAT Personal Training, Cincinnati, Ohio; and

14

Department of Kinesiology, University of Waterloo,Waterloo, Ontario

A B S T R A C T

FUNDAMENTAL MOVEMENT COM-

PETENCY IS ESSENTIAL FOR

PHYSICAL ACTIVITY PARTICIPA-

TION AND FOR REDUCING INJURY

RISK, WHICH ARE BOTH KEY

ELEMENTS OF HEALTH PROMO-

TION. THE SQUAT MOVEMENT

PATTERN IS ARGUABLY ONE OF

THE MOST CRITICAL FUNDAMEN-

TAL MOVEMENTS NECESSARY TO

IMPROVE SPORT PERFORMANCE,

TO REDUCE INJURY RISK, AND TO

SUPPORT LIFELONG PHYSICAL

ACTIVITY. BASED ON CURRENT

EVIDENCE, THIS FIRST (1 OF 2)

REPORT DECONSTRUCTS THE

TECHNICAL PERFORMANCE OF

THE BACK SQUAT AND PRESENTS

A NOVEL DYNAMIC SCREENING

TOOL THAT INCORPORATES

IDENTIFICATION TECHNIQUES FOR

KNOWN FUNCTIONAL DEFICITS.

THE FOLLOW-UP REPORT WILL

OUTLINE TARGETED CORRECTIVE

METHODOLOGY FOR EACH OF

THESE FUNCTIONAL DEFICITS.

INTRODUCTION

F undamental movement skills areessential for participation inphysical activity and mitigating

the risk of injury, which are both keyelements of health throughout life (25).Young people, for example, withoutadequate motor skill proficiency in theearly developmental years may experi-ence a heightened risk of sports-relatedinjuries during adolescence and intoadulthood (11,32,34). Thus, develop-

ment of competence in fundamental

movements must be viewed as an essen-tial component of preparatory training before vigorous physical activity andorganized, competitive sport. Some fun-damental movement patterns includerunning, throwing, lunging, and squat-ting (25). These fundamental move-ments have direct biomechanical andneuromuscular implications to success-

ful performance with dynamic tasksinherent to many popular sports andphysical activities enjoyed by youthand young adults (24,35). Movementcompetency as a principle extendsthrough into the later adult years, forwhom the joy of independent living

K E Y W O R D S :

functional deficit identification; injury pre-vention; physical activity; screening tool;sport performance; squat

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rests on their ability to maintain strengthand mobility to avoid injuries such asfalling (44).

The squat movement pattern is required

for essential activities of daily living,such as sitting, lifting, and most sporting activities. It is also a staple exercise intraining regimens designed to enhanceperformance and to build injuryresilience (30–32). Despite variationson how squat technique is instructedand executed to address specific per-formance goals, nearly all squat varia-tions comprise a standard, basic, andfundamental blueprint that underliesthe biomechanical technique that willsupport progressive physical attribute

improvements and decrease the risk of training induced injuries (3). In addi-tion, the unloaded back squat (hereinreferred to as “back squat”) has beenproposed for use as a screening tool toidentify biomechanical deficits thatmay hinder optimal movement pat-terns compromising performance andinjury resilience (20). In particular, theback squat can be used to assess anindividual for neuromuscular control,strength, stability, and mobility withinthe kinetic chain (1,4,10,31,39,42).

The purpose of this commentary is todeconstruct the technical performanceof the back squat and the related evi-dence, as both a foundation training exercise and dynamic screening tool.Specifically, we aim to describe com-mon functional deficits during back squat performance known to increase

injury risk during training and dynamicsport. Identified deficits and injurymechanisms will be formalized togetherwith anatomical variations that influence

squat kinematics and kinetics. In thefollow-up manuscript, we aim to presentdetailed targeted training exercises andtechniques to correct biomechanicaldeficits (part II), which is vital toimprove the technical skill and compe-tence of the back squat (22). Achieving this competency is the foundation foryounger individuals to partake in training progressions that enhance performanceand injury resilience, and for older adultsto live independently and safely (25).

THE BACK SQUAT

The back squat is widely regarded asone of the most effective exercises usedto enhance athletic performance becauseit necessitates the coordinated interac-tion of numerous muscle groups andstrengthens the prime movers neededto support explosive athletic move-ments, such as jumping, running, andlifting (7). Furthermore, back squat pro-ficiency supports derivative squat move-ments that translate to many everyday

tasks, such as lifting and carrying heavyobjects, which relates this exercise toimprove quality of life (43). The squathas also become more commonly usedin clinical settings to strengthen lower-body musculature (especially posteriorchain strength and recruitment patterns)with little to no harm on connective tis-sue after joint-related injury (7,43).

Specifically, closed kinetic chain exer-cise is commonly used throughout therehabilitation process to avoid excessivestrain being placed on the anterior

cruciate ligament, making the squata favorable exercise for rehabilitation(7,17,37,43). It is highly recommendedthat an individual is first able todemonstrate proficiency during bodyweight back squat performance beforeadvancing to more intense variationsand derivatives of squatting, such asexternally loaded squats and plyometrictraining.

The back squat exercise is most oftenprescribed with an individual starting in a standing position with the feet flaton the floor, the knees and hips ina neutral, extended anatomical posi-tion, and the spine in an upright posi-tion with preservation of its naturalcurves (7,43,45). The squat movementbegins with the descent phase as thehips, knees, and ankles flex. A commoninstruction is to descend until the topof the thigh is at least parallel withground and the hip joint is at least levelwith or slightly below the knee joint(Figure 1) (3,43). Ascent is achieved

primarily through triple extension of the hips, knees, and ankles, continuing until the subject has returned to theoriginal extended, starting position (3).The posterior torso muscles, particu-larly the erector spinae, are recruitedby isometric muscle action to supportan upright posture throughout theentire squat movement. Furthermore,

Figure 1. Recommended squat depth presented from the anterior, posterior, and lateral perspective.

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the posterior torso muscles are assistedby the anterior and lateral abdominalmuscles to further stiffen the torso bycreating tension for the abdominal wall.

Before the initiation of the descentphase, it is recommended for the ath-lete to inhale approximately 80% of maximal inhalation and hold theirbreath to increase intra-abdominalpressure to enhance stability of the ver-tebral column (i.e., Valsalva maneuver)(note: this amount of air may changewith the load magnitude). This tech-nique prepares the spine, which is a flex-ible rod, to bear a compressive load.The Valsalva maneuver also establishes“proximal stiffness” that enables more

power development in the shouldersand hips, enhancing limb force outputand velocity.

IDENTIFICATION OFBIOMECHANICAL DEFICITSDURING THE BACK SQUAT

The basic squat movement is consideredby many professionals to be a valuableprimary physical training exercisebecause it is a single compound maneu-ver that is highly sensitive to highlightbiomechanical deficits (12,13,33,42). Def-

icits identified during the back squat thatcan impair performance can be catego-rized as inefficient motor unit coordina-tion or recruitment (neuromuscular),muscle weakness, strength asymmetryor joint instability (strength), and/or jointimmobility or muscle tightness (mobility)(43). It is important to identify the bio-mechanical and anatomical limitation(s)that most egregiously underlies aberrantmovements to ameliorate identified def-icit(s) through an appropriate and effec-tive targeted corrective strategy (part 2)(12,13,33,42). With the use of the pro-posed Back Squat Assessment (BSA)screening tool (Table 1), a practitionermay be able to more efficiently andobjectively identify underlying deficit(s)responsible for functional limitations dur-ing back squat performance and to guidecorrective targeted exercise progressions.

THE BACK SQUAT ASSESSMENT

The authors of this commentary devel-oped the proposed BSA (Table 1)

screening tool to assist practitioners

in systematically identifying specificfunctional deficits to guide targeted cor-rective intervention. The authors proposethat observed movement impairments or

deficits through guidance of the BSAsuggest that an individual may have anelevated injury risk and suboptimal phys-ical performance (4). Moreover, the BSAis a versatile tool that provides an alter-native means to expensive and sophisti-cated laboratory evaluation to identifybiomechanical deficits.

Ten criteria to be scored are provided inthe BSA, which are subcategorized into3 comprehensive domains: upper body,lower body, and movement mechanics(Table 1). The 3 domains are integratedinto the BSA to improve the systematicassessment of the back squat. It may bechallenging to score all 10 criteria of theBSA at once during real-time observa-tion. The categorization of similar criteria into 3 domains offers a practitioner a stra-tegic guide to focus attention on scoring 1 domain at a time. The upper bodydomain emphasizes the stability and pos-ture of the head, neck, and torso. Thelower body domain assesses the jointpositions of the hips, knees, and ankles

during the squat. Finally, the criteria inthe movement mechanics domain assessthe timing, coordination, and recruit-ment patterns of the back squat. All 10criteria from the 3 domains can beindividually assessed for neuromuscular,strength, and mobility deficits as promp-ted on the BSA score sheet (Table 1).

To initiate the assessment, the athleteshould be asked to perform 10 contin-uous back squat repetitions. The BSAwill necessitate analysis from the ante-

rior, posterior, and lateral perspectivesand therefore it may be advantageousfor practitioners to record video of theathlete performing the BSA from all 3perspectives to facilitate a more accu-rate and thorough deficit screening.

The criteria are written in the affirma-tive and each should be critiqued andscored independently of each other. If a single criterion is not met to standard,an observed deficit should be marked.Next, the practitioner should indicate if

they believe the deficiency is related to

a neuromuscular, strength, or mobilitylimitation by circling the respective cat-egory to guide targeted exercise correc-tions (part 2). If unsure, mark all

categories that are suspect to impropertechnique. A perfect score of 0 indicates10 flawless squat repetitions. A deficitshould be marked if the individual failsto demonstrate the desired techniqueof a criterion to perfection during 2 ormore repetitions. Additional space forcomments is provided on the scoresheet and may be useful for a practi-tioner to make supplementary notesto guide their targeted corrective inter-vention. An athlete should be referredto a licensed health care professional if

they indicate pain or discomfort during any phase of the squat assessment.

STANDARDIZED ASSESSMENT

BACK SQUAT INSTRUCTION

For the purpose of maximizing theconsistency of the assessment, theBSA should be administered with armposition, stance, and verbal instructionin standardized fashion.

ARM POSITION INSTRUCTIONS

A lightweight cylindrical dowel(wooden, metal, or plastic; approxi-mately 1¼$ 3 36$ long) is recom-mended to be used to set-up theathlete in a desired upper torso posi-tion while controlling for arm posi-tion. Furthermore, the use of a dowelin the back squat position can serveto prepare an athlete for future back squat progressions that incorporateexternal resistance. In addition, thedowel-aided position likely facilitatesengagement of the scapular stabi-

lizers essential to upper body perfor-mance in the back squat.

Athletes are to be instructed to gripthe dowel with a pronated grip slightlygreater than shoulder width apart andassume a back squat set-up, with thedowel resting comfortably on theircontracted upper back musculature.Specifically, the dowel should be posi-tioned across the posterior deltoids

just below C7 of the cervical spine.Forearms should be held parallel to

the torso, and wrists should be kept

The Back Squat

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Table 1



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straight and not flexed throughout themovement (Figure 2). The personshould be taught to “bend the bar” (pullthe bar into trapezius) because this

facilitates the back extensors, shoulderretractors, and latissimus—all of whichstiffen the torso, adding to injury resil-ience and performance capabilities. If a dowel is not available, the athletecan be instructed to mimic holding a dowel with their hands open palmedunder their ears while retracting theirscapulae.

STANCE INSTRUCTIONS

The athlete should be instructed toassume an initial stance position withheels approximately shoulder widthapart and toes pointing forward orslightly outward by no more than108. Extreme stance widths and footpositions (tibial rotation) are not rec-ommended when initially instructing the squat and may limit the utilityof the BSA. Escamilla et al. (8) assessedthe kinematics and kinetics of the squatat 3 varying widths (a wide stance,shoulder width, and narrow stance).A wide stance may increase patellofe-

moral and tibiofemoral compressive

forces in the knee joint by up to 15%during descent (7,9,43). However, anexcessively narrow stance may increaseforward knee translation and there-

fore heighten anterior shear forces(7,43). Therefore, a moderate stancewidth is encouraged for this standard-ized assessment.

Regarding foot position, it is impor-tant for the knee to function in its in-tended role as a hinge joint. During goal-specific squat exercise, moderatevariations of foot placement may bewarranted; however, it is recommen-ded that athletes do not exceed 308 of internal ankle rotation or 808 of exter-

nal rotation to maximize stability andpromote normal patella tracking (21,43). Still, extreme tibial rotationin a closed chain movement maypotentially lead to increased stresson the static knee structures andshould be avoided for most squatvariations.

SCRIPT FOR INSTRUCTING THE ASSESSMENT

Once the athlete is properly set-up

with the dowel and stance in the

appropriate position, verbal instruc-tions for the BSA can be delivered.The authors recommend using thefollowing standardized verbal script

to promote inter-rater reliability forthe BSA:

“Please stand upright with feet shoul-der width apart. Squat down until thetop of your thighs are at least parallelto the ground, and then return to theinitial starting position. Perform 10continuous repetitions at a consis-tent, moderate pace or until you areinstructed to stop.”

Set-up Summary

Arm position: A dowel is held in back squat position with forearms parallelto torso and upper back musculaturecontracted.

Stance: Feet are placed with heelsshoulder width apart and toes forwardor slightly outward.

Script: “Please stand upright with feetshoulder width apart. Squat down untilyou believe that the top of your thighsare parallel to the ground, and thenreturn to the initial starting position.

Perform 10 continuous repetitions ata consistent, moderate pace, or untilyou are instructed to stop.”

DOMAIN 1: UPPER BODY

Domain 1 focuses on the musculoskel-etal components of the upper bodythat are responsible for maintaining postural control during the squat.

HEAD POSITION

As a precursor to sports performancetraining for youth, the neck shoulddemonstrate adequate physiologicalranges of motion of flexion, extension,rotation, and side bending in theabsence of pain or discomfort. Simpleneck rolls and head tilts can be used asan assessment for neck mobility. If anathlete indicates pain or discomfortwhen attempting to achieve physio-logical ranges of neck motion, it isadvised to abstain from training andrefer the individual to a licensed health

care professional.

Figure 2. Forearmposition with dowel.

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Maintaining the head and neck in neu-tral alignment (to slight extension)with the torso is an important facetto provide the athlete with a strong,

balanced set-up and point of referencethroughout the squat (6). Incorrect posi-tioning of the head and neck may neg-atively cascade into improper spinalpositioning and tracking throughoutthe range of the movement (6). In the-ory, the spine, although comprisedmany vertebral links, acts as a singleentity. A change in alignment in 1 sec-tion of the spine may influence compen-sation in another section. Furthermore,poor body alignment as a result of incorrect head position may predispose

an athlete to injury during more intensesquat exercises (6,15).

Practitioners should be aware thathead position and gaze direction (focalpoint) are related but independent.Gaze can be directed by keeping fixedeyes and moving the head, or by mov-ing the eyes independently of a fixedhead (6). Both head position and gazehave been shown to influence spinalkinetics and kinematics (43).

Desired technique. Head positionThe athlete’s head should be maintainedin a neutral position (to slight extension)

in relation to the spine (Figure 3). Theneck should be held in line to the planeof the torso.

Gaze

Point of focus for gaze is instructed tobe either straight ahead or slightlyupward (Figure 3) (6). It is hypothe-sized that athletes may have a ten-dency to move in the direction of their gaze and therefore a downwardgaze is not recommended during ascent. A slightly upward gaze during ascent may help guide an athleteto lead with their head and chestrather than raising their hips firstwhen beginning the concentric por-

tion of the squat. In addition, a slightupward gaze throughout the move-ment may help prevent excessive for-ward trunk flexion.

Screening. Observe the athlete’s headposition from the lateral perspectives.From the lateral perspective, chin posi-tion and anterior/posterior head tiltcan be observed. From the anteriorperspective, assess the athlete’s direc-tion of gaze.

Common deficits. Head positionMost athletes will be able to achieveproper head position during the initial

set-up phase for the squat. Musclestrain or injury to the cervical verte-brae during exercise may result fromimproper neck position. Therefore,

movement of head too far forwardor backward and movement of headlaterally to either side should beexplicitly avoided. Excessive tilting of the head backward into a positionof extreme cervical hyperextensioncan be dangerous during the squat,particularly when heavy resistance isintegrated (2). Excessive cervicalhyperextension may be a compensa-tory movement for a lack of thoracicextension. Excessive cervical flexionmay also result in a greater tendency

to extend the lumbar spine, which canincrease lumbar compression forces(Figure 4). Conversely, if head posi-tion is directed too far downward intocervical hyperflexion, a significantincrease in hip and trunk flexionmay result as a compensation mecha-nism, which is not considered an opti-mal movement strategy for the back squat and other sport activities such astackling in football (6). From the pos-terior perspective, ensure that theathlete’s neck position is perpendicu-

lar to the line of the shoulder andthere is no lateral head tilt in eitherdirection. If an athlete is unable to

Figure 3. Correct head position.



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maintain his or her head and neck in a neutral position throughout the entiresquat, the deficit may either be due toneck muscle weakness (i.e., trapeziusmuscles) or inadequate posturalawareness.

Gaze

Gaze can either be directed too highor too low. A downward gaze hasbeen shown to increase hip flexionand potentially trunk flexion incomparison with an upward gaze(Figure 4). This position may placeincreased torque on the vertebral col-umn (2,6,43). However, it is impor-tant to disassociate gaze from headposition. Although gaze can beslightly upward, the head positionshould not deviate from neutral. Mosterrors concerning gaze direction can

be corrected by verbal and visualcueing.

Head Position Deficits Summary

Neuromuscular: Unsatisfactory headand neck position awareness formaintaining neutral head positionthroughout squat. Poor disassocia-tion of gaze from head position,which may encourage deviation fromneutral head position.

Strength/stability: Insufficient isomet-

ric strength of neck and upper back

musculature to maintain head in neu-tral alignment throughout the entiresquat.

Mobility: Insufficient physiologicalrange of motion for head and neck inall 3 planes.

THORACIC POSITION

The athlete must be able to demon-strate adequate postural stability andcontrol of the upper torso as optimalsquat technique favors a rigid spinethat does not concede to any planarmotion. Stable, upright posture shouldbe sustained throughout the move-ment as a more vertically positionedupper spine, contracted upper back musculature, and chest-up position re-duces shear forces on the interverte-bral disks.

Desired technique. It is preferred thatthe thoracic spine is slightly extendedand held rigid (3). The chest isdirected outward and upward to bring the torso angle to a more vertical posi-tion (3), and this position should bemaintained throughout the entiresquat movement. The chest can bepositioned upward independently of trunk angle (criterion 3). The scapulaeshould be held retracted anddepressed while the glenohumeral

joint maintains a position of relative

external rotation, which pushes outthe chest and keeps the upper torsoerect (Figure 5). As a result, theshoulders will assume a slightly rolledback position. The athlete’s forearmsshould be held parallel to their spineand the shoulders should be retractedand not rolled forward. This positionallows for major supporting back

muscles (i.e., latissimus dorsi, erectorspinae, trapezius, rhomboids) to con-tribute maximally to spinal stability(28). In addition, a tight upper back with retracted scapulae can help pro-vide the athlete with a favorable posi-tion to rest the dowel in the most secureand comfortable manner during back squats (28).

Screening. Observation of the upperspine and chest position can bemade primarily from the lateral

perspective.

Common deficits. A thoracic positionin which the chest is not held upwardand is positioned toward the groundsignifies a deficit in the back squattechnique (Figure 6). In addition,any flexion or excessive extension of the thoracic spine, either constantlyor sporadically, may be indicative of biomechanical compensatory strate-gies (3). Another deficit of the upper

torso is that the scapulae are relaxed

Figure 4. Incorrect head position.

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or abducted (i.e., “protracted scap-ula”) and visually evidenced as hav-ing the shoulders rolled forward. If verbal or physical cueing to instructthe athlete to position their chest

up or retract their shoulders doesnot gain desired technique, then

the athlete may lack adequatetorso strength, such as the thoracicparaspinal musculature or parascap-ular musculature, or insufficientneuromuscular coordination to per-

form the exercise to standard. A pro-pensity for forward rolled shoulders

during the back squat may also bedue to lifestyle-induced posturalweaknesses (i.e., upper crossed syn-drome, which results from consis-tently internally rotated shoulders

leading to excessively shortened ortight pectorals).

Figure 5. Correct thoracic position.

Figure 6. Incorrect thoracic position.



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Thoracic Position Deficits Summary

Neuromuscular: Chest down or lack of scapular retraction during squat. Diffi-culty dissociating the thoracic position

from the lower trunk position.

Strength/stability: Inability to main-tain chest-up position, which may bedue to weakness of erector spinae, tra-pezius, and rhomboids.

Mobility: Excessive tightness in chest,potentially from upper crossed syn-drome, which hinders ability to openchest and retract scapula.

TRUNK POSITION

Trunk stability and control are derived

from the lower back musculature,obliques, lumbar paraspinals, quadra-tus lumborum, and abdominals. Thebody’s core is a critical modulator of lower extremity alignments and loadsduring dynamic tasks such as squatting (33). The stabilizers of the trunk andhip can preactivate to counterbalanceunwanted trunk motion and regulatelower extremity postures during thesquat (33). Decreased core stabilityand muscular synergism of the trunk and hip stabilizers negatively affect per-

formance in power activities and mayincrease the incidence of injury due tolack of control of the center of mass

(14,33). The squat exercise can helpinstill mechanics that improve trunk stability during dynamic tasks.

Stability during the squat is enhanced

with muscular stiffness of all musclesaround the lumbar spine. Failure tostiffen the lower back musculature,combined with poor lifting mechan-ics, increases the potential to overloadspine and back tissues to the point of injury, especially when repeated overtime (27,29). A more upright lumbarposture increases load onto lowerextremity levers, which may reducelow back stress. Some may dismissthe need to preserve the neutral cur-vature of the lumbar spine when

squatting. However, this is problem-atic as the spine loses its ability to bearload when the neutral curve is lost,which prevents eventual progressionof the squat with load while maintain-ing a reduced injury risk. In summary,the individual must demonstrate theability to maintain a stiffened torsowith a neutral, lordotic lumbar posi-tion as a safe and optimal squatstrategy.

Desired technique. The lumbar verte-brae are maintained in a neutral align-ment throughout the entire squat

movement (28). This entails main-taining a slight lordotic curve in thelumbar region while holding theabdomen upward and rigid to pro-

mote stability (Figure 7). The trunk should remain as upright as possibleduring the squat to minimize lumbarshear forces associated with forwardlean (28). Furthermore, the trunk should remain stable throughout thesquat without any observation of wavering or displacement. A generalguideline to ensure adequate trunk posture is to necessitate that the lineof the trunk is maintained parallel tothe line of the tibias from the lateralperspective. However, this guideline

also necessitates proper foot and kneeposition.

Screening. Observation of the lumbarspine and trunk angle can be made pri-marily from the lateral perspective.

Common deficits. It is suboptimal forthe trunk musculature to be ina relaxed state and allow the trunk to collapse downward into excessivetrunk flexion (Figure 8). The musclesform a guide wire system that pre-

pares the flexible spinal columnto bear load and they must be acti-vated. Common culprits for increased

Figure 7. Correct trunk position.

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trunk flexion during the squat areweakness of the thoracic and lumbarparaspinals (erector spinae), weaknessof the parascapular musculature tomaintain retracted and depressedscapulae, and reduced tension in the

thoracolumbar fascia through theintegration of the posterior chainand back musculature. In addition,restricted translation of the knees dur-ing the squat may also increase ante-rior forward lean of the trunk (16). Atrunk that is unsteady and moves outof an upright position during thesquat may be indicative of generalcore weakness.

The squat requires sufficient spinalmobility to assume and maintain slightlordotic posture. Otherwise, an indi-vidual may tend to take forward pos-ture and place excessive pressure tothe lower back, especially if their headis tilted forward as well. Insufficient hipmobility may also negatively affect theability to preserve a lordotic spine,which may be due to genetics, previ-ous injury, or tight connective tissues.If the athlete flexes at the spine before1208 of hip flexion when squatting,they may have restriction in the poste-rior fibers of the illiotibial band or lack

of lumbar control.

Observation of a rounded spine, orkyphosis, due to relaxed back muscu-lature and spinal flexion indicatesa deficit for the BSA (Figure 8). If anathlete does not stiffen the back mus-culature to support the spine posi-

tioned in a neutral, slightly lordoticposition, increased and potentiallyharmful compressive and shear forcesof the lumbar spine may result during more intense squat variations (28). Therisk of disc herniation is increased dur-ing heavy resistance squatting, withthe spine in a flexed position as a resultof excessive stress placed on interver-tebral discs (26,43).

The most critical component to cor-recting a deficit with the lumbar spineand abdomen is identification of themechanism driving the failure todesired technique. Due to the com-plex nature of this area, one or a com-bination of problems could exist.Having the athlete execute a squatto at least parallel with only a dowelas the external resistance will allowthe coach to gauge when and if theathlete presents a movement patternincluding excessive anterior or poste-rior pelvic tilt. If the athlete is unableto maintain a slight lordotic curve in

the lumbar spine and keep the trunk

angle parallel with the tibial angles,then specific corrective actions shouldbe taken (part 2).

Trunk Position Deficits Summary

Neuromuscular: Excessive trunk flex-

ion and/or rounding (kyphosis) of the spine during the back squat.

Strength/stability: Inadequate corestrength to maintain torso parallel totibias and lack of lower back tightnessto generate spinal stability. Deficit maybe due to trunk extensor weakness andhip extensor weakness.

Mobility: Excessive hip flexors (iliop-soas) and trunk flexors (abdominals)tightness and/or lack of lumbar spinalmobility.

DOMAIN 2: LOWER BODY

Domain 2 encompasses the musculo-skeletal components and positions of the 3 major joints of the lower extrem-ities during the back squat.

HIP POSITION

The hip joint is a ball-and-socket jointcapable of motion in all 3 planes. It isresponsible for providing a pathway of the transmission of forces between the

lower extremities and the pelvis during

Figure 8. Incorrect torso position.



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squatting (43). Evidence suggests thatmaintaining a neutral pelvic tilt during the squat increases activity of the erectorspinae and oblique muscles, helping to

ensure optimal muscular support for thespine while handling loads, therebyreducing the risk for low back injury (5).

The gluteus maximus is the largestmuscle of the hip. During the squatmovement, the gluteus maximus ex-tends the femur and stabilizes the pel-vis (43). The squat can be an effectivetraining exercise to promote the devel-opment of gluteal strength, which isimportant for athletes as these musclesare prime movers in dynamic sports-related movements, such as running and jumping (33). Furthermore, with-out proper recruitment of the glutealmuscles, other muscle groups, such asthe quadriceps, must bear the load of the squat, which is suboptimal andmay increase the risk of muscle imbal-ance and injury. The hamstrings are anassemblage of 3 muscles, including thebiceps femoris, semitendinosus, andsemimembranosus, which originateon the pelvis and insert at the top of the bones of the lower leg (43). Because

the hamstrings cross both the hips and

the knees, they moderate movements atboth joints (33). During descent, thehamstrings can assist the gluteal musclesby controlling flexion at the hips (43). In

the ascent phase of the squat, the distalhamstrings contract to extend the hips.The hip abductors, muscles of the hipand outer thigh, including the gluteusmedius and the gluteus minimus, stabi-lize the femurs during the squat. Theyprevent the knees and hips from rotating inward during descent. Moreover, inter-nal rotation of the femurs may be causedby tight hip adductors, muscles on theinner thigh (1).

Desired technique. The athlete main-

tains square, stable hips with minimalmediolateral movement during the squat(Figure 9). Squat depth should be deter-mined based on the position of the hips(2). The position of the femurs shouldremain symmetrical throughout theentire exercise (2). It is optimal if the lineof the hips from the frontal perspective isparallel to the ground. The athlete is alsoencouraged to maintain the pelvis in nor-mal/neutral tilt, particularly during thedescent phase of the movement. Thisis particularly important in the final part

of the descent.

Screening. A deficit can be identifiedby observing the athlete leaning, drop-ping, or twisting to one side from theanterior or posterior perspective.

Common deficits. Observation of me-diolateral rotation or unilateral dropping,which results in asymmetrical hip move-ment, constitutes a deficit of the hipposition. This deficit is evident if the lineof the hips is not parallel to the groundin the frontal plane (Figure 10). Hipasymmetries may be due to weaknesses,muscle imbalances in the gluteal com-plex, or joint asymmetries involving thehip capsule and labrum. It has been re-ported that an athlete lacking hip mobil-ity will demonstrate a compensatorymovement pattern of increased trunk flexion (3). Hip position deficits can benoted through observations of one hippositioned lower than the other in thefrontal plane or observation of the doweldropping down to one side during the squat.

Hip Position Deficits Summary

Neuromuscular: Hips are asymme-trical in frontal plane during the

back squat.

Figure 9. Correct hip position.

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Strength/stability: Lack of strength orstability of hip musculature or asym-metrical strength of hips.

Mobility: Lack of hip flexor range of motion.

FRONTAL PLANE KNEE ALIGNMENT

Internal knee force response to externalloads is primarily generated by thequadriceps, hamstrings, and gastrocne-mius (43). Tibiofemoral compressiveforces help resist anteroposterior shearforces and translation (43). Tibiofemoraland patellofemoal compression has beenshown to increase with increasing kneeangle as a protective function at the kneeby initiating a co-contraction betweenthe quadriceps and hamstrings (43).Therefore, closed kinetic chain exercisessuch as the back squat exercise may sup-port appropriate rehabilitation exerciseafter ligament reconstruction surgery(16). Although shear forces tend toincrease with increasing knee angles,forces on the cruciate ligaments of theknee decrease at high flexion angles (43).Thus, there is no known evidence tosupport the contention that squat depthbelow parallel increases the potential for

injury to the cruciate and collateral

ligaments and menisci in the knee dur-ing deep flexion (43). Training with thesquat exercise may enhance passive anddynamic knee stability in deep knee flex-ion positions by active muscular protec-

tion of the passive structures during sport movements (7,8,19,39).

Desired technique. The knees shouldtrack over the toes throughout the squatmotion visually evident as a neutral fron-tal plane knee position throughout themovement (i.e., the foot is positioned tocreate a perfect in-line hinge with kneemotion). There should be an absence of knee displacement both medially andlaterally. The lateral aspect of the kneeshould not cross the vertical plane of the medial malleolus when assessing for medial displacement (Figure 11).Although the goal position is to havethe tibia in vertical alignment perpendic-ular to the floor with error toward lateralknee positions, the medial aspect of theknee should also not cross the verticalplane of the lateral malleolus.

Screening. Observe excessive medio-lateral movement of the knees fromthe anterior perspective (i.e., knock

kneed position).

Common deficits. Excessive mediolat-eral movement of the knees signalsa functional deficit. Valgus or varus fron-tal plane movement can be attributed topoor neuromuscular control and lack of

function or strength of the lowerextremity musculature, especially theposterior chain complex. Knee valgus(medial or knock-kneed movement)during the squat may be influenced bydecreased hip abductor and hip externalrotation strength, increased hip adduc-tor activity, and restricted ankle dorsi-flexion (4). Observed valgus during thesquat may due to a suboptimal activeneuromuscular pattern of the athlete.Active valgus, which is a position of hip adduction and knee abduction asa result of muscular contraction, is oftenthe underlying cause for observeddynamic valgus during the back squat.From an observational standpoint,medial knee motion is a much morecommon deficit relative to knee varus(outward movement of the knee). How-ever, knee varus can occur and is some-times a compensatory strategy used byathletes with flat feet. A neutral kneealignment is desired and feedback should be given to correct varus or val-

gus positioning during the movement.

Figure 10. Incorrect hip position.



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Knee valgus can be identified by obser-vation of the medial aspect of eitherknee passing the medial malleolus fromthe anterior perspective during anyphase of the squat (Figure 12).

Frontal Knee Position Deficits Summary

Neuromuscular: Active valgus during the back squat; increased hip adductoractivation without adequate posteriorchain control and recruitment maylead to knee valgus.

Strength/stability: Posterior chainweakness which leads to passive valgusduring squat motion.

Mobility: Hip immobility that restrictsknees from avoiding valgus positionduring squat.

TIBIAL TRANSLATION ANGLEAs a general rule, increased anteriortibial translation increases torqueabout the knee joint (16). Although thisobservation has led some practitioners

to caution against allowing the knees totravel past the toes, there is no knownevidence that a defined point existswhereby injury risk exceeds the poten-tial benefits during the squat exercise.Moreover, a conscious effort to restrictforward translation has been shown to

increase forward trunk lean, resulting in significantly greater forces at thehip and spine that place these jointsat greater risk of injury (16,23). Thus,on the proviso that feet remain firmly

Figure 12. Incorrect knee position.

Figure 11. Correct frontal knee position.

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fixed on the floor, anterior tibial trans-lation angle should be unrestrictedwith the focus on initiating the squatdescent by breaking the hips back (16).Adequate tibial translation angle is ableto be achieved by normal foot andankle capsular mobility, soft-tissue flex-

ibility, and proper joint mechanics.

Desired technique. Although thegeneral goal should be to maintain

a positive shin angle, this objectiveshould be accomplished by properhip joint kinematics (16,45). Theknees therefore should move freely inaccordance with hip range-of-motion.The extent of anterior tibial transla-tion will vary between individuals

depending on anthropometrics, inparticular the torso and leg lengthratio. As a general guideline, the ath-lete should attempt to match tibia

angle in parallel with an upright trunk while keeping their heels on theground (Figure 13).

Screening. Observe tibial translationfrom the lateral perspective.

Common deficits. Athletes mayeither demonstrate excessive transla-tion or excessive restriction of thetibial progression angle (Figure 14).

Figure 13. Correct tibial translation.

Figure 14. Incorrect tibial translation.



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Excessive anterior translation of theknees over the toes is purported toincrease shearing forces on the kneeand greater knee extensor torque (30).

Overly restricted tibial translationduring the squat increases anteriorlean of the torso, which accompaniesincreases in hip torque and lumbarshear forces (16). The optimal posi-tion of tibial progression anglemay support active muscular recruit-ment of the lower extremity whileavoiding unwanted stresses on thepassive structures. Often weak glutealmuscles influence the body to usea strategy to alternatively place loadon the knees increasing tibia progres-

sion rather than on the rear (33).Excessive tibial progression anglecan also be exacerbated by weaknessin the calf and soleus, weak hamstrings,or quadriceps dominance. Restrictedmotion of the gastrocnemius andsoleus muscle complex by the Achillestendon, talocrural joint restrictions at

the posterior ankle, restrictions in hipmobility, and deficits in foot mobilitymay also hinder proper tibial progres-sion angle. An evaluation by

a licensed health care provider maybe necessary if a good stretching andmobility routine for the posterior calf musculature does not improve properperformance.

Tibial Translation Angle Deficits Summary

Neuromuscular: Knee translates exces-sively over toes during the back squat,even with heel on the ground.

Strength/stability: Lack of strength of posterior chain, particularly the glu-

teals, to keep load on the rear. Exces-sive tibial progression angle can bea result of weakness in calf andsoleus, weak hamstrings, or quadri-ceps dominance.

Mobility: Inadequate mobility of kneein sagittal plane from lack of mobilityof the soleus and gastrocnemius.

FOOT POSITION

Adequate ankle mobility supportsa balanced and controlled squat move-ment. However, foot and ankle posi-

tion can be influenced by proximalforces as well, which may need to beruled out to determine the cause of themovement deficit. The ability of theathlete to maintain a flat and stablefoot position during the back squatnecessitates adequate ankle dorsiflex-ion (3).

Desired technique. Ensure the ath-lete’s feet are stable and planted firmlyon the ground. The athlete should keeptheir entire foot on the ground

throughout the entire squat motion(Figure 15). The suggested center of pressure in the foot moves from themid-foot during initial stance towardthe heel and lateral foot (“L” foot load-ing position) during the descent phaseof the squat, and bodyweight is distrib-uted through the lateral foot and heel

Figure 15. Foot position.

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until the athlete completes the ascent(3). As the athlete descends, bodyweight should be emphasized throughthe heel and lateral foot while keeping

the toes on the ground to ensure bal-ance. Placing more body weighttoward the back of the foot facilitatesdesired hip motion strategies during the entire squat phase. In addition,placing more body weight toward thelateral aspect of the foot encouragesimproved recruitment of the glutealmuscles.

Screening. Observe foot position fromthe lateral, anterior, and posterior per-spectives to assess for any aspect of the

foot coming off of the ground.

Common deficits. Observations of pronation or supination of the feetand the rolling of the feet inward oroutward are suboptimal movementstrategies. Lifting heels or toes off of the ground at any time is suboptimalduring the back squat (Figure 15).Allowing the heels to rise off theground has been observed to createcompensatory torques about the ankles,knees, hips, and lumbar spine (3). Withheels raised off of the ground, the ath-lete has a smaller surface area and baseof support, which may reduce theathlete’s ability to perform a balancedand controlled squat.

Ankle inversion or eversion during the squat is also indicative of a biome-chanical deficit. Although pressureshould be emphasized toward thelateral side of the foot, the medialside should not come off of theground to promote balance and sta-

bility. The calcaneus should notappear everted relative to the lowerleg (20). Stiffness in the ankle jointfrom poor dorsiflexion may causethe foot and the knee joints to com-pensate (3). These compensationsmay have a negative impact to footand knee stability that is needed forcorrect squat mechanics.

Furthermore, weakness in the anklemusculature has been implicated infaulty movement patterns during the

squat. A lack of strength in the medial

gastrocnemius, tibialis anterior, and/ortibialis posterior decreases the athlete’sability to control knee valgus and footpronation motions and may contribute

to excessive medial knee displacementand dynamic valgus (1). Althoughincreasing ankle mobility, and in manycases hip mobility, is the desired end-point for this deficit, some athletes maybenefit initially from the use of a heelblock to aid in creating a stable plat-form and assist in pushing throughthe heels.

Foot Position Deficits Summary

Neuromuscular: Foot comes off of ground during squat not due to

strength or mobility limitations.

Strength/stability: Lack of or asym-metrical ankle strength and/or poorstabilization of ankle and foot. Footrolls onto either side during squat.

Mobility: Lack of dorsiflexion mobilityif heels come up off ground due torestricted Achilles tendon and/or tightsoleus and gastrocnemius.

DOMAIN 3: MOVEMENTMECHANICS

Domain 3 analyzes the kinematics of the squat and discusses the limitationsof functional deficits on proper move-ment mechanics. Triple extension(extension of ankle, knee, and hip)and flexion movement patterns areinherent to sports-associated move-ments, such as jumping and landing mechanics.

DESCENT

After achieving a proper set-up, theathlete is instructed to initiate thesquat movement with the descentphase. Throughout the descent, theathlete should maintain full controlof their velocity and descending position. The athlete should descendby flexing the hip, knees, and anklesin a fluid, coordinated movement asthe body is lowered in a controlledmanner.

Desired technique. The descent isinitiate d with the breaking of

the hips (“hip hinging”) while

maintaining a rigid, upright trunk.Breaking the hips at the initiationof the squat movement migrates theload to the posterior chain, which is

a more safe strategy for the knees andlumbar vertebrae (33). The athleteshould reach back as if sitting ina chair that is slightly too far awayas they descend to the desired depth.The goal should be for the athlete tokeep their rear as far away from theirankles while maintaining an uprighttorso throughout the squat. The ver-tical distance between the athlete’sshoulders and hips should remainconstant throughout the entiredescent. Body weight should be

transferred to and supported by theathlete’s posterior chain muscula-ture, particularly the hamstringsand gluteals, and not placed anteri-orly on their knees (Figure 16). Thedescent of the squat should moveback in a vector that remains at a con-stant downward angle The athleteshould move at a controlled tempowith no less than 2:1 (descent:ascent) up to a 4:1 ratio in regardto velocity of the eccentric move-ment compared with the concentric

ascent phase.

Screening. Observe descent techniqueand tempo from the lateral perspective.

Common deficits. Observation of excessively rapid or unsteady move-ment of the body during descentshould be considered a deficit. Inaddition, incorrect descent mechan-ics may also be noted if the athletedoes not maintain constant speedand control during the entire eccen-tric phase, which is particularlycommon in novice lifters (31). Fur-thermore, a common mechanical def-icit is for athletes to place load downon the anterior aspect of the kneesrather than back on the hips during descent (Figure 17). Typically, thisincorrect strategy can be observedwith, but not limited to, excessive tib-ial progression angle (criteria 6) and/or heels coming off of the ground(criteria 7). This incorrect descent

strategy may place excessive shear



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forces on the anterior knee and de-creases recruitment of the posteriorchain musculature. Athletes withinsufficient posterior chain (i.e., ham-

strings, gluteals) strength may bemore likely to lose descent control

toward the later phases of the move-ment and may favor a knee loading strategy. In addition, more intensesquat variations, such as high velocity

eccentric movements, can be danger-ous if the muscles are forced to

stretch too greatly in a short amountof time. Practicing and mastering controlled descent strategies supportthe development of strategies that

can mitigate risk of training inducedinjuries.

Figure 17. Incorrect descent mechanics.

Figure 16. Correct descent mechanics.

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Descent Deficits Summary

Neuromuscular: “Knee-loading” strat-egy instead of “hip-hinge” strategy asseen with excessive trunk flexion,

excessive tibial progression angle,and/or heels coming off of theground.

Strength/stability: Lack of lower limbeccentric strength control, evidencedby an overall lack of control of thetempo of the descent. The athleteseems to “drop” into the apex of thedescent. Descent timing is not a 2:1ratio in relation to ascent.

Mobility: Lack of lower limb mobility,leading to a forward trunk lean.

DEPTH

Squatting to appropriate depth is a crit-ical component in deriving the fullbenefit of the activity. Without squat-ting to the proper depth, the ham-strings and gluteus muscular complex may not be adequately challenged. Spe-cifically, training at shallower knee flex-ion can influence quadriceps-dominantsport skill performance that can limitperformance and increase injury risk (19,39). Likewise, training at deeper

depths will help benefit motor controlpositions that are common to sport.The skill and strength gains achievedduring deep knee and hip flexion posi-tions may help reduce quadriceps dom-inance strategies that are purported toincrease injury risk (18,37,38). As notedpreviously, evidence that indicatessquatting below parallel increased thepotential for injury to the cruciate andcollateral ligaments or menisci in theknee during extreme flexion does notexist (43). The squat exercise may

enhance active knee stability if per-formed correctly and may reduce sportinjury risk to the passive structures of the knee (7,8,39).

Desired technique. The athleteachieves full depth with the tops of the thighs at least parallel to theground without any disjointed devia-tions noted at the knee, ankle, or hips.At the proper depth, the femurs areslightly past parallel to the ground,

hips are back, tibias are positioned

vertical, and feet are entirely on theground (Figure 18). Furthermore, thisposition allows the squatter to achievedesired depth by not falling victim to

soft tissue restrictions such as thethighs blocking the abdomen, thushindering the ability to achieve anappropriate depth (2).

Screening. Observe the apex of depthposition from the lateral perspective.

Common deficits. The most commondeficit of depth during the back squatis from the athlete squatting tooshallow (Figure 19). Although squat-

ting excessively past parallel canoccur, it is not often detrimental tothe athlete. If contraindicated basedon existing pathology, excessive squatdepth can be easily corrected withcueing and feedback. The athletemay lack isometric strength of theposterior chain to maintain body-weight support at the apex of depth.Furthermore, tightness in the poste-rior chain musculature and hip ad-ductors may further limit the abilityfor an athlete to achieve appropri-ate depth.

Depth Deficits Summary

Neuromuscular: Athlete does notachieve depth of thighs at least parallelto the ground.

Strength/stability: Athlete lacks poste-rior chain isometric strength to main-tain deep hold.

Mobility: Difficulty achieving depthdue to tightness in posterior chain

and hip adductors.

ASCENT

The ascent of the squat should followthe same path as the descent in thereverse direction. The primary driverof the ascent should be the hips, andweight should be kept of the heels andlateral sides of the feet. The torso of the athlete should remain fairly staticthroughout the ascent as the ankles,knees, and hips extend into the original

position.

Desired technique. The torso shouldremain upright during the entireascent phase. The shoulders and hipsshould rise at the same pace and the

difference in vertical height of theshoulders and hips should remainconstant (Figure 20). The back is tobe kept in a rigid, tight position withstiffened muscles and with the lumbarspine in a neutral to slightly extendedposition. The athlete should use a hipdrive strategy as the primary driver forthe ascent. The athlete should onlyexhale once the ascent has beencompleted.

Screening. Observe ascent technique

and tempo from the lateral perspective.

Common deficits. Common faults inearly stages of learning the back squat(i.e., early training age) are for thehips to rise faster than the shoulders,which would increase trunk flexion(Figure 21). If the hips rise too quickly,the vertical distance between thehips and shoulders will decrease during the early ascent phase (Figure 21).Irrespective of the load, the movement

pattern represents an incorrect back squat that can be a dangerous strategyto the lower back during squatting with progressive external resistance.In addition, relative to the downwarddescent, a large deviation in the move-ment pattern used during upwardascent is also considered a deficienttechnique.

Knee position during ascent may alsogreatly influence mechanics. If theknees are too far back in relation tothe trunk, the athlete is forced to leanforward with their torso to stay in bal-ance. If the knees are too far forward,an acute shift of postural balance oc-curs, requiring the athlete to shifttheir body weight onto their toesinstead of their heels. This strategyinfluences an inefficient hip drive outof the transition phase of the move-ment. Typically, mechanical deficits of ascent are due to suboptimal motorrecruitment patterns that can beimproved through neuromuscular

training and corrective cueing feedback.



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Ascent Deficits Summary

Neuromuscular: Hips rise too quickly inrelation to shoulders during ascent. Thevertical distance between the hips and

shoulders does not remain constant.

Strength/stability: Posterior chain andhip extension concentric muscle action

weakness.

Mobility: Lack of thoracic spine and

hip flexor mobility.

ADDITIONAL CONSIDERATIONSFOR THE SQUAT

ANATOMICAL VARIATION

The proposed form and technique in

the 10 BSA criteria are meant to be

Figure 18. Parallel squat depth.

Figure 19. Incorrect depth.

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set as an ideal standard for all athletes.

However, it is understood that anatom-

ical variation may predispose some ath-

letes to have disadvantages in achieving

these desired positions and mechanics.

The factors of anatomical variationmost influencing the squat are the

anatomy of the hip, together with the

ratio of torso length to leg length. The

shape of the hip joint determines the

type and incidence of specific hip

pathology and squat depth. While

a deeper hip joint increases standing stability to the joint, it prevents the

femur from flexing into a deep squat

without pinching the hip joint labrum

and joint capsule. This bony restriction

nullifies any attempt to stretch or mobi-

lize the joint to perform the deep squat.

Assessment of this feature begins withthe individual kneeling on their hands

Figure 20. Correct ascent mechanics.

Figure 21. Incorrect ascent mechanics.



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and knees. The knees are initiallyplaced together. Then the pelvis isrocked back toward the heels. The teststops when the neutral spine curvature

begins to flex. Then the knees arespread apart a few inches and the “pel-vic rock” test is repeated and the depthof the kneeling squat is noted. In thisway, the ability to deep squat withoutcompromising the back curvature isquantified, together with identifying the optimal width for the feet and kneeswhen squatting.

Other suggestions for squat safetyinvolve knee loading and whether theknee may be allowed to travel ahead of the toe. This also is a function of the leg

length and torso length ratio. A 7-foottall basketball center usually has longerlegs than torso, such that the kneestravel way ahead of the toes. Thelength of the femur creates a long leverand a high patellar tendon load. Gener-ally, these athletes squat with their hipsback to balance the knee and hip loads.In contrast, an individual with a longertorso to leg length ratio squats withmore emphasis on knee motion, andthe shin remains parallel to the torso,equally sharing hip and knee loads.

INTEGRATING THE SQUAT INTO ATHLETIC PREPARATION TRAINING

Participation in organized sports doesnot safeguard youth from developing poor or inefficient movement patterns.Athletes who do not demonstrateproper mechanics may use compensa-tory movement strategies that can hin-der their athletic performance andheighten their risk of sports-relatedinjury (4,24). In the absence of pres-sures or cueing during activity to mod-ify these inefficient movements,athletes will continue to master andimprint these suboptimal strategiesthat will likely propagate into move-ments used in sport competition.Non-athletes with poor squat mechan-ics will more likely suffer the same fateof eventual pain and suboptimal perfor-mance. The back squat offers an oppor-tunity to teach and instill a correctfunctional movement pattern provid-

ing the foundation upon which to build

strength and mobility abilities. Forexample, it is suggested that the squatreflects lower extremity movementpatterns often required for success in

explosive sport techniques that arelikely to expose the lower extremityto high joint loads (4). Improved strat-egies to help young athletes absorb,redirect, and create explosive squat-related movements can help enhanceperformance outcomes and reduceinjury risk factors (36,39). On a morebroad level, preservation of the compe-tency to squat can prolong indepen-dent living in older adults.

Proficiency with the back squat isa prudent prerequisite to heavy resis-

tance squat training, especially foryoung athletes with a low training age (35). An individual should be ableto display perfect back squat tech-nique consistently before moving on to more advanced squatting variations, including depth jumpplyometric training. In addition, bydeveloping proper squat mechanicsbefore using external resistance, an ath-lete can minimize the potential toinstill improper compensatory strate-

gies and decrease the risk of training-related injuries (34). It is outside thescope of this review to discuss themany useful technical variations of the squat movement (i.e., sumo squat,front squat). However, it is advisedthat athletes do not increase theintensity of the squat (i.e., increaseresistance) unless the athlete can dem-onstrate consistent, proper form of theback squat. Specifically, the back squatis used first in the battery of squatvariations to teach the parent move-

ment pattern and identify functionaldeficits. If taught and progressed cor-rectly, technique should remain thesame as exercise intensity is increased.Part 2 of the discussion will detail cor-rective strategies to target specificfunctional deficits identified during the squat.

It should be noted that the back squat is only one recommendedcomponent of a comprehensive neu-romuscular training program for

youth. Integrative neuromuscular

training targeted for the physicaldevelopment of youth should con-sider a variety of cognitive- andtraining-age appropriate exercises to

adequately prepare a child for therigors of moderate to intense physi-cal activity (34,40). Integrative neuro-muscular training programs for youthshould be appropriately designed tomeet the needs and goals of aspiring young athletes while considering their current ability level (24). It ishighly recommended that qualifiedintegrative neuromuscular training professionals who understand thepsychosocial uniqueness of youthcontribute to the design, supervision,

and implementation of training pro-grams for young athletes to minimizethe risk of training-related injuriesand to promote acquisition of soundexercise technique (24,34). Integra-tive neuromuscular training pro-grams for youth are most effectivewhen designed and progressed to besafe and training-age appropriate(11,34,35,41).

CONCLUSIONS

The assessment of the unloaded back

squat is meant to be a guide for trainersand coaches to identify and targetcorrections for biomechanical deficitsof young athletes before participationin more advanced and intense physi-cal training activities. By teaching andcorrecting optimal form of a basicfunctional movement inherent tomany popular dynamic sports, an ath-lete can become more sufficiently pre-pared for the rigorous demands of physical activity. Furthermore, byinstilling proper mechanics in youth,individuals may be more inclined toelicit optimal performance gains andreduce injury risk. It is recommendedthat instructors make careful observa-tions during analysis of the squatassessment. These observations areimperative in developing individual-ized targeted corrective interventions.Part 2 of this commentary will covertargeted corrective training progres-sions and methodology for the com-mon deficits for each criterion

discussed in this manuscript (22).

The Back Squat



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Through identification and correctionof functional deficits by the body-weight squat, practitioners can greatlyassist young athletes to reap the ben-

efits of improved performance andreduced injury risk to promote suc-cessful athletic careers and long-termphysical well-being.

Conflicts of Interest and Source of Funding: The authors would like to acknowledge

funding support from National Institutes of Health.

Gregory D.Myer is director of

Research and the Human Perfor- mance Labora- tory for the Division of Sports Medicine at Cincinnati Children’s Hos-

pital Medical Center and holds primary academic appointments in the Depart- ments of Pediatrics and Orthopaedic Surgery within the College of Medicine at

University of Cincinnati .

Adam M.Kushner i s a Clinical Research Coor- dinator in the Human Perfor- mance Labora- tory for the

Division of Sports Medicine at Cin- cinnati Children’s Hospital Medical

Center .

Jensen L. Brentis the owner and director of training at The Academy of Sports Perfor- mance in Cin-

cinnati, and head strength and conditioning coach for the Cincinnati

Kelts Rugby Football Club .

Brad J.Schoenfeld i s an assistant professor in

exercise science at CUNY Lehman College and director of their Human Performance Laboratory .

JasonHugentobler i s a sports medicine physical therapist at Cincinnati Children’s Hos- pital Medical

Center .

Rhodri S. Lloydis a senior lec- turer in Strengthand Condition- ing at Cardiff

Metropolitan University .

Al Vermeil is President of Ver- meil Sports and Fitness, Inc. spe- cializing in athletic assessment,conditioning and

training .

Donald A. Chuis the director of the Athercare Fitness and Rehabili tation Clinic in Pleasanton, CA,and a professor and adjunct

faculty at

Ohlone College.

Jason Harbin i s the head trainer at Beat Personal Training .

Stuart M.McGill is a professor of Spine Bio- mechanics at the University of

Waterloo .

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The Back Squat a Proposed Assessment

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