Date of Award
Doctor of Philosophy
Exercise and Sport Sciences
Clare E. Milner
Songning Zhang, Jeffrey T. Fairbrother, Russell L. Zaretzki
Background: Epidemiological studies have demonstrated higher ACL injury rates in female athletes when compared to males involved in the same sport. A recent meta-analysis of ACL injury prevention programs found that technique training was a common component of programs that were successful in reducing ACL injury.
Purpose: The primary purpose was to determine the immediate and long-term effects of technique training aimed at minimizing medial knee displacement during jump-landings in female recreational athletes. The secondary purpose was to determine if any transfer of skill occurred as a result of our technique training.
Study Design: Controlled laboratory study.
Methods: A total of 26 participants who presented with medial knee displacement during a basketball rebound screening task completed the study protocol. Participants were randomly assigned to two groups (experimental and control groups, 13 each). The experimental groups received jump landing instructions aimed at minimizing medial knee displacement. The control group received "sham" training consisting of jump training for maximum height. Baseline motion analyses of participants performing a basketball rebound task were performed prior to participants receiving technique training. Immediate and delayed retentions tests were performed after the initial instructional session and after home-based training. Additionally, motion analyses were also performed on a stop-jump task during the baseline assessment and the delayed retention test to help in determining if any transfer occurred.
Results: The initial instructional session resulted in increased knee excursion and reduced peak knee adduction moments in the experimental group. Following home-based training, the experimental group continued to exhibit increased knee excursion along with decreased landing forces. No evidence of transfer was present following the initial training session or after home-based training.
Conclusion: Our jump training instructions led to temporary changes, most notably increased knee excursion about the sagittal plane. No transfer of skill occurred as a result of our training.
Clinical Relevance: Technique training instructions aimed at reducing medial knee displacement resulted in increased sagittal plane motion, but were unable to minimize medial knee displacement. ACL injury prevention programs may need to include a variety of drills, tasks, and sport-specific movements.
Tate, Jeremiah Jackson, "The Effect of Technique Instruction on Biomechanical Risk Factors Associated with ACL Injury Risk in Female Recreational Athletes. " PhD diss., University of Tennessee, 2010.