Muscle Recruitment Strategies in Preadolescent Male and Female Soccer Players Performing a Landing Task

Publication Date


Type of Culminating Activity


Degree Title

Master of Science in Exercise and Sport Studies



Major Advisor

Ron Pfeiffer


Michelle B. Sabick


Chad Harris


Introduction: This study examined muscle recruitment strategies employed by preadolescent male and female soccer athletes relative to the muscles around the knee when performing a one–legged landing task.

Methods: Twenty-seven preadolescent soccer players, 16 females (age 11.2 ± 0.6) and 11 males (age 11.5 ± 0.8), participated in the study. Surface electrodes were placed over the rectus femoris, vastus lateralis, vastus medialis, medial hamstring, lateral hamstring, and the medial head of the gastrocnemius. Subjects hung from a horizontal bar approximately 38.1 cm above the ground and dropped onto a floor mounted force plate landing on one leg. Force data and sEMG (surface electromyography) was used to assess muscle activation patterns, timing of peak forces, and timing of initial contact with the force plate. Muscle onset was defined as signal of at least 50ms duration at least three standard deviations above baseline. Initial contact (IC) as well as peak resultant ground reaction force (Fr) were identified from each trial. Further analysis yielded the dependent variables that were the time interval (ms) between muscle onset and both IC and Fr.

Results: Statistical analysis revealed no significant differences between preadolescent males and females with respect to the timing of muscle onsets of the six muscles of interest relative to either IC or Fr.

Conclusions: Preadolescent male and female soccer athletes display similar muscle recruitment strategies when performing a one-legged landing. These findings are in conflict with adult studies that noted differences in recruitment strategies when performing landing tasks. This suggests that differences seen in adult populations may be related to morphologic changes associated with pubescence.

Clinical Relevance: The increased susceptibility of non-contact ACL injuries in female athletes may be related to factors such as age related morphological changes or learned landing techniques.

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