Acl Risks w Lateral Cutting

8/3/2019 Acl Risks w Lateral Cutting

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Journal of Applied Biomechanics,2009, 25, 9-21

2009 Human Kinetics, Inc.

The purpose o this study was to compare theknee joint dynamics or males and emalesperorming constrained cutting tasks to anunanticipated running and cutting maneuver.

Sixteen male and 17 emale recreational ath-letes were recruited to perorm our cuttingtasks; unanticipated run and cut (CUT), strideland and cut (SLC), ar box-land and cut(FLC), and close box-land and cut (CLC).Three-dimensional knee joint kinematics andkinetics were recorded. Data were comparedacross gender and task with a 2 4 ANOVA(p < .05), and a actor analysis was perormedto examine task relationships. There were sig-nicant group mean dierences between thetasks and across genders. The actor analysisrevealed high correlations between the threeconstrained tasks, but or variables typically

associated with ACL injury risk there was apoor relationship to the CUT task. This wasparticularly true or the rontal plane vari-ables. The constrained tasks were only mod-erately useul in predicting cutting mechan-ics.

Keywords: anterior cruciate ligament, sidestepcutting, lower limb, gender

Injuries to the anterior cruciate ligament (ACL) arealarmingly common or emale athletes, in which they

occur at a rate between two and seven times greater thanor males (Arendt et al., 1999; de Loes et al., 2000).Many o these injuries occur in noncontact situations,particularly during changes in direction as happensduring sidestep cutting maneuvers (Boden et al., 2000).

The authors are with the Neuromechanics Laboratory, Depart-

ment o Human Movement Sciences, University o Wiscon-

sinMilwaukee, Milwaukee, WI.

Comparison of Selected Lateral Cutting Activities Usedto Assess ACL Injury Risk

Kristian M. OConnor, Sarika K. Monteiro, and Ian A. Hoelker

University of WisconsinMilwaukee

Given the prevalence o noncontact ACL injuries whenperorming this maneuver, the mechanics o the kneeduring a running and cutting maneuver and the potentialor associated gender dierences have received a great

deal o attention. Appropriate neuromuscular control isrequired to avoid extreme joint positions, and the resultso previous studies suggest that emale athletes displayknee joint mechanics during cutting that may increasethe risk o injury (Malinzak et al., 2001; Pollard et al.,2004; Sigward & Powers, 2006). In particular, thesestudies have reported that emales fex less (Malinzak etal., 2001; McLean et al., 2005b), abduct more (Malin-zak et al., 2001; McLean et al., 2004), and experience agreater peak internal adduction moment at the knee(McLean et al., 2005a) during stance. These gender di-erences are also consistent with the ndings o Hewettet al. (2005), who reported that subsequently injuredemales athletes exhibited less knee fexion and greater

knee abduction during a two-leg drop jump (Hewett etal., 2005). In addition, increased ACL loading has beenobserved when internal rotation orces are applied to thetibia (Li et al., 1999; Markol et al., 1995), and exces-sive rotation has been qualitatively identied as com-monly occurring during noncontact ACL injuries (Bodenet al., 2000).

While not validated, it has been suggested that anunanticipated cutting maneuver may elicit a responsebest refective o movement patterns during play (Besieret al., 2001a, 2003). These studies reported greater load-ing and muscle activity around the knee when an unan-ticipated cutting maneuver was employed. Aside romPollard et al. (2004), most running and cutting studieshave used anticipated tasks (Malinzak et al., 2001;McLean et al., 1999, 2004). There are several exampleso more constrained tasks to explore knee dynamics.Hass et al. (2003, 2005) used single-leg box and stridelanding tasks ollowed by a lateral cut and reportedpostpubescent mechanical changes that may relate toincreased injury risk. Ford et al. (2005) also employed alateral box landing maneuver that included an unantici-pated response. Simpler landing and jumping protocols


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10 OConnor, Monteiro, and Hoelker

Methods

Sixteen recreationally active (dened as physicallyactive or 30 min at least 3 days per week) males (22.7 2.7 years, 86.1 13.5 kg, 1.81 0.08 m) and 17 rec-reationally active emales (20.9 1.5 years, 62.9 5.9kg, 1.68 0.06 m) volunteered to participate in this

study. A power analysis was perormed based on pilotdata to detect a between-subject 2 rontal plane dier-ence with an alpha o .05 and 80% power. The clinicalsignicance o this kinematic threshold was supportedby the results o Withrow et al. (2006). Thirty total sub-

jects (15 o each gender) were sucient to detect thisdierence, and additional subjects were collected toaccount or possible dropouts. A background question-naire to screen or health status and an inormed consentorm were read and signed by all volunteers beore thebeginning o the study. The protocol was approved bythe university institutional review board. Volunteerswere accepted in the study i they had not suered a

knee injury requiring surgery and have been ree o anyother injury within the previous six months that couldinterere with normal movements. Subjects were alsoasked how many years they competed (i any) in com-petitive team sports. Males participated 11.4 3.4 years,and emales participated 6.4 4.0 years.

To track lower extremity kinematics, twenty-velight-refecting skin markers were placed on the partici-pants (Figure 1). Markers used exclusively or the stand-ing calibration trial (calibration markers) included thelet and right iliac crests and greater trochanters, andstance leg lateral and medial emoral epicondyles, lat-eral and medial malleoli, and rst and th metatarsalheads. Additional tracking markers were placed on the

let and right antero-superior iliac spines, the sacrum,two our-marker plates attached to elastic Velcro strapson the thigh and shank segments, and a marker triadsecured on the heel counter o the shoe. The calibrationmarkers were removed ater standing calibration trialcompletion. Participants wore standard laboratory oot-wear (Saucony Jazz, Lexington, MA). Marker trajecto-ries were collected at 200 Hz with a seven-cameraMotion Analysis Eagle System (Santa Rosa, CA, USA),and ground reaction orces were collected synchro-nously at 1000 Hz with an AMTI OR65 orce plate(Watertown, MA, USA). Running speed was monitoredthrough two gates 2.5 m apart positioned along therunway just beore the athlete reached the orce plate.

There were two sessions or this study. During therst session, subjects practiced the required tasks untilthey could comortably complete the our tasks. Subjectalso completed three maximum two-leg countermove-ment jumps on the orce plate to calculate jump height.During this session, subjects practiced the our tasks: anunanticipated running and cutting maneuver, and threediscrete single-leg landing tasks incorporating an imme-diate 90 lateral cut (Figure 2). All tasks were perormedon the subjects dominant leg, which was determinedrom the subjects preerred jumping leg. This resulted

have also been used by several or use in large-scaledata collections and postatigue assessments (Augusts-son et al., 2006; Chappell et al., 2005; Fagenbaum &Darling, 2003; Hewett et al., 2005; McLean et al., 2007)The constrained tasks are advantageous because theycan be collected more quickly. Tasks originating rom abox or a single stride are easier to experimentally con-

trol and avoid issues with accurate speed control andoot placement. Given the prevalence o injuries duringcutting, tasks with lateral movement may provide moredirect insight into injury risk than studies that used sin-gle-plane landing and jumping tasks. It is unknown,however, whether the knee dynamics observed by Hasset al. (2003, 2005) can be directly related to those o themore demanding running and cutting task. For example,the greater horizontal velocity o the center o mass ora running and cutting maneuver will likely cause sub-stantially greater loading and potentially lead to qualita-tively dierent dynamic patterns. Thereore, the ques-tion remains as to whether a constrained task can yield

critical inormation about an individuals knee mechan-ics during a running and cutting maneuver, which maybetter approximate dynamics during play.

McLean et al. (2005b) examined the possible utilityo a constrained land and cut task in understanding kneedynamics during play. They compared the lower extrem-ity mechanics o an anticipated cut with those o a jump-land and a shuttle run. While peak knee abduction di-ered between genders, there was a high correlationbetween peak knee abduction across tasks. Since it hasbeen previously demonstrated that an unanticipated cut-ting maneuver resulted in dierent joint mechanics andmuscle activation patterns (Besier et al., 2001a, 2003),the results o McLean et al. (2005b) do not necessarily

demonstrate that these tasks can be used to approximateknee dynamics associated with the inherent randomnesso game play.

Given the wide variety o protocols currentlyemployed in the study o knee mechanics and their rela-tionship to ACL injury risk, there is a need to understandhow the nature o the experimental protocol aects theconclusions reached. Ideally, a constrained task willproduce kinematic and kinetic patterns that, while likelydierent in magnitude, are at least correlated to lessconstrained tasks such as running and cutting. To explorethis relationship, the purpose o this study was to com-pare the knee joint kinematics and kinetics or individu-als perorming side cutting maneuvers starting romthree static positions to an unanticipated running andcutting maneuver. It was hypothesized that the magni-tudes o kinematic and kinetic parameters or con-strained tasks would dier rom an unanticipated cut-ting maneuver (CUT), but that the constrained taskparameters would correlate highly with the CUT task. Itwas also hypothesized that a constrained task thatincluded both a vertical and horizontal impact velocity(ar land and cutFLC) would best correlate to theCUT task and that gender would not aect the degree ocorrelation between tasks.


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Comparison of Cutting Mechanics 11

(Figure 2b). The close-land and cut (CLC) maneuverwas initiated rom the same box height used or the FLCwith the box placed a distance to the center o the orceplate equivalent to the box height (Figure 2c).

The testing session was scheduled within one weeko the practice session. Following a 5-min joggingwarm-up, markers were placed on the participants, anda 2-s calibration trial was collected. Each participantthen completed ve trials o each cutting task. Thesetrials were considered valid only i the stance oot wasentirely on the orce plate. For logistical reasons, theCUT was perormed rst, but the order o the three staticlanding tasks was subsequently randomized. These ourtasks were part o a larger data collection protocol whereseveral single- and two-leg landing and jumping activi-ties were recorded during a session that lasted ~90 min(data not presented here). The CUT task was perormedat the beginning o the protocol to minimize eects omental atigue, allowing greater success in respondingto the visual stimulus.

Custom-made sotware calculated countermove-ment jump height rom the ground reaction orce (GRF)curve (Luhtanen & Komi, 1978). The highest jumpheight was used to set the landing height or the FLC

in 29 right limb and our let limbdominant subjects.For the unanticipated cutting maneuver (CUT), subjectsapproached the orce plate at 4.55.0 m/s and were pre-sented with a visual stimulus to either continue runningstraight ahead, stop quickly, or side cut 45. The speedis similar to the range (4.55.5 m/s) used by McLean etal. (2004), and the cutting angle and visual stimuluswere based on the protocol used by Pollard et al. (2004).The cutting angle was guided by a 1-m wide runwayoriented 45 rom the line o progression (restrictingmovement between ~35 and 55), and trials weredeemed successul i the subject was able to remain onthe runway. The visual stimulus was triggered by therst timing gate that was ~3 m beore reaching the orceplate. The stride-land and cut maneuver (SLC) requiredsubjects to leap rom the nondominant to the dominantleg rom level ground (Figure 2a). Subjects initiated thetask rom as ar as possible rom the orce plate whilestill being able to complete the task, which was based onthe task used by Hass et al. (2003). The subjects alsoperormed a ar-land and cut (FLC) maneuver, whichwas initiated rom a box height equal to their maximumcountermovement jump height at a distance equal tothree times the box height away rom the orce plate

Figure 1 Frontal and sagittal plane views o the locations o retro-refective markers. Markers on the right and let ASIS andPSIS, and marker plates on thigh, leg, and oot remained or dynamic trials, whereas the rest were removed ater the standing cali-bration trial.


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Figure

2

(

ac)Initialposition

forthethreeconstrainedlandandcuttask

s:(a)stridelandandcut(SLC),(b)farlandandcut(FLC),and(c)closelandandc

ut(CLC)


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Comparison of Cutting Mechanics 13

the actor analyses were perormed on each gender sep-arately. A total o 18 separate actor analyses were con-ducted (9 dependent variables or each gender). TheANOVA and actor analysis were perormed with SPSS(v13.0, Chicago, IL).

Results

ANOVA Results

Kinematics. There were no signicant gender taskinteractions or any o the kinematic variables, nor werethere dierences between the box landing tasks (FLCand CLC; Figure 3 and Table 1). There was a signicanttask main eect or the sagittal TD angle (p < .001),with the greatest fexion at TD occurring or the SLCand least occurring or the FLC (Figure 3 and Table 1).There were gender (p = .010) and task (p < .001) maineects or sagittal ROM. Females fexed signicantlyless when averaged across all tasks, and the least fexion

occurred or the CUT. Signicantly greater fexionoccurred during the box landing tasks. In the rontalplane, only the TD angle diered between tasks (p

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