BackgroundThe etiology of Anterior Cruciate Ligament (ACL) injury in women football results from the interaction of several extrinsic and intrinsic risk factors. Extrinsic factors change dynamically, also due to fatigue. However, existing biomechanical findings concerning the impact of fatigue on the risk of ACL injuries remains inconsistent. We hypothesized that fatigue induced by acute workload in short and intense game periods, might in either of two ways: by pushing lower limbs mechanics toward a pattern close to injury mechanism, or alternatively by inducing opposed protective compensatory adjustments.AimIn this study, we aimed at assessing the extent to which fatigue impact on joints kinematics and kinetics while performing repeated changes of direction (CoDs) in the light of the ACL risk factors.MethodsThis was an observational, cross-sectional associative study. Twenty female players (age: 20–31 years, 1st–2nd Italian division) performed a continuous shuttle run test (5-m) involving repeated 180°-CoDs until exhaustion. During the whole test, 3D kinematics and ground reaction forces were used to compute lower limb joints angles and internal moments. Measures of exercise internal load were: peak post-exercise blood lactate concentration, heart rate (HR) and perceived exertion. Continuous linear correlations between kinematics/kinetics waveforms (during the ground contact phase of the pivoting limb) and the number of consecutive CoD were computed during the exercise using a Statistical Parametric Mapping (SPM) approach.ResultsThe test lasted 153 ± 72 s, with a rate of 14 ± 2 CoDs/min. Participants reached 95% of maximum HR and a peak lactate concentration of 11.2 ± 2.8 mmol/L. Exercise duration was inversely related to lactate concentration (r = −0.517, p < 0.01), while neither%HRmax nor [La–]b nor RPE were correlated with test duration before exhaustion (p > 0.05). Alterations in lower limb kinematics were found in 100%, and in lower limb kinetics in 85% of the players. The most common kinematic pattern was a concurrent progressive reduction in hip and knee flexion angle at initial contact (10 players); 5 of them also showed a significantly more adducted hip. Knee extension moment decreased in 8, knee valgus moment increased in 5 players. A subset of participants showed a drift of pivoting limb kinematics that matches the known ACL injury mechanism; other players displayed less definite or even opposed behaviors.DiscussionPlayers exhibited different strategies to cope with repeated CoDs, ranging from protective to potentially dangerous behaviors. While the latter was not a univocal effect, it reinforces the importance of individual biomechanical assessment when coping with fatigue.
Biomechanical movement screens are commonly used to identify potential risk factors contributing to a variety of musculoskeletal injuries. Such an approach is challenging for anterior cruciate ligament (ACL) injuries given the low incidence rate. However, resulting time loss from sport and poor long-term health outcomes justify the need to begin to use available data. A comprehensive assessment of lower extremity joint mechanics during running is a useful first step in exploring potential movement-related risk factors for ACL injuries. PURPOSE: To determine if healthy, baseline running mechanics differ between collegiate athletes who did and did not go on to suffer a primary ACL injury. METHODS: Whole body kinematics and ground reaction forces (GRF) during treadmill running were collected as part of pre-season performance testing. Thirteen division I collegiate athletes (6 female; 19.1±1.1 years, 86.8±17.0 kg, 1.79±0.10 m) went on to suffer an ACL injury (PRE). HC (n=13) were matched to PRE (6 female, 18.9±1.0 years, 86.2±17.1 kg, 1.79±0.08 m, 4.2±0.4 m/s and by sport). Multiple statistical parametric mapping (SPM) paired t-tests (α = 0.05) were used to explore differences between PRE and HC for vertical GRF, ankle, knee, and hip angles, moments, and powers during the stance phase of running for injured and uninjured limbs. HC were randomly assigned an injured limb. RESULTS: No significant difference were detected between PRE and HC athletes for any variable on either limb during the stance phase of running (all SPM{t} values < critical threshold tvalues). Figure 1 depicts the SPM results for knee angles, moments, and powers of the injured limb. CONCLUSIONS: Pre-season screening of running biomechanics in collegiate athletes is unlikely to identify those at risk for sustaining an ACL injury. Screening higher risk movement patterns may reveal ACL injury risk factors. NIH award TL1TR002375.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.