Differential biomechanical effects of an ACL injury prevention program in women’s basketball and soccer players

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Jeffrey Bruce Taylor (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Sandra J. Shultz

Abstract: Anterior cruciate ligament (ACL) injury prevention programs are considerably less successful in women’s basketball than women’s soccer. Despite different sport-specific demands (e.g. more jumping and frontal plane movements in basketball), ACL injury prevention programs have been uniformly administered in both sports and predominantly emphasize improving high-risk biomechanics during sagittal plane tasks. As such, injury prevention programs may not provide the appropriate stimulus to reduce ACL injury risk during the high-risk demands associated with women’s basketball. Thus, the purpose of this study was to 1) compare the fundamental movement profiles in adolescent female basketball and soccer players during a variety of jump landing tasks, 2) assess whether an established ACL injury prevention program affects lower extremity biomechanics during sagittal vs. frontal plane and double- vs. single-leg landings, and 3) analyze the extent to which female basketball and soccer players respond differently to a uniform ACL injury prevention program. A repeated measures experimental design was used in this study. Middle- and high-school aged female basketball and soccer teams were cluster-randomized into intervention (basketball, n=21; soccer, n=27) and control (basketball, n=21; soccer, n=28) groups. Three-dimensional biomechanical analysis was performed during double- and single-leg sagittal and frontal plane tasks before and after the completion of an established 6-week ACL injury prevention program. Biomechanical variables of interest were those that have been theorized to influence ACL injury risk, including hip flexion, adduction, internal rotation, and knee flexion, abduction, internal rotation and external rotation peak angles, excursions, and peak normalized external joint moments. At baseline, basketball players exhibited relatively stiff landings, with less hip and/or knee excursion than soccer players. Sport differences were especially apparent as jump landing tasks increased in difficulty, with the single-leg, frontal plane jump landing eliciting the most differences. During this task, basketball players landed with decreased hip adduction angles (p<.001), decreased hip flexion (p=.03), and knee flexion (p=.01) excursions, and increased hip internal rotation (p=.003) and greater relative knee external rotation (p=.001) excursions. Additionally, forces differed between sports during the single-leg frontal plane jump landing, with basketball players showing increased knee abduction (p=.003) and decreased hip adduction (p=.001) and knee external rotation (p<.001) moments. Across sports, no significant biomechanical changes were identified after the training program in any of the sagittal or frontal plane jump landing tasks (p>.05). However, limited evidence suggested that biomechanical changes were not the same across all tasks, as participants in the intervention group showed relative decreases in knee abduction moments during the double-leg sagittal plane landing compared to the single-leg sagittal plane landing (p=.005). Additionally, women’s basketball and soccer players largely exhibited similar biomechanical adaptations after training. No significant differences in biomechanical adaptations were identified between sports during the drop vertical jump, double-leg sagittal plane, or double- and single-leg frontal plane tasks (p>.05). During the single-leg sagittal plane jump landing task, basketball players in the intervention group exhibited increased peak knee abduction angles (p=.004) and excursions (p=.003) after training compared to the basketball control group (p=.01) and soccer intervention group (p=.01). These results indicate that the discrepancy in the success of ACL injury prevention programs in basketball and soccer players may not be a function of sport-specific responses to training. Instead, basketball players appear to utilize distinct fundamental movement strategies during a variety of jump landing tasks compared to soccer, and therefore, current prevention programs may not successfully address these sport-specific movement differences. Specifically, basketball players land in potentially higher-risk positions, with decreased levels of hip and knee flexion excursion, and elements of dynamic lower extremity valgus, which are especially prevalent during high level basketball-specific tasks, including jump landings on a single-leg and in the frontal plane. However, 6-weeks of offseason training using a warm-up based ACL injury prevention program does not appear to provide adequate volume or intensity to modify the high-risk movement patterns used during these tasks. Thus, to improve the success of future programs in the basketball population, exercise prescription may need to incorporate higher levels of more intense technique training that emphasizes soft landings during basketball-specific frontal plane and single-leg jumping activities.

Additional Information

Language: English
Date: 2016
Anterior cruciate ligament, Basketball, Biomechanics, Injury prevention, Injury risk
Anterior cruciate ligament $x Wounds and injuries
Women athletes $x Wounds and injuries
Knee $x Mechanical properties
Knee $x Physiology
Sports injuries $x Prevention

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