Ashley L. Erdman, Charles W. Wyatt, Kirsten Tulchin-Francis, Sophia M. Ulman

Research output: Contribution to journalReview articlepeer-review

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Background: Lower extremity asymmetry has been shown to be associated with increased risk of anterior cruciate ligament injury. Return-to-sport screens commonly involve assessing the restoration of symmetrical strength and balance. Therefore, it is important to understand how these measures are related. Hypothesis/Purpose: To determine if relationships exist between the Lower Quarter Y-Balance Test (LQ-YBT) component scores, composite scores, and isokinetic knee strength in healthy, female athletes. Methods: Female adolescent athletes completed the LQ-YBT and isokinetic knee strength as a part of a comprehensive evaluation in competitive level athletes (Tegner activity scale≥7). LQ-YBT anterior, posteromedial, and posterolateral component scores for the each leg were normalized to leg length, and composite scores for each leg were calculated for each participant. Knee flexion/extension strength was collected at 120°/second using a Biodex System 4. Peak torque was normalized by body weight, and paired t-tests were used to compare legs (α<0.05). Spearman correlation coefficients were calculated to test whether any LQ-YBT measures were associated to knee strength. Results: A total of 106 participants (age 13.8±2.4 years; BMI 20.2±3.0) were tested, and all were right leg dominant. No differences were found between LQ-YBT right and left component (Table 1), or composite scores (right 97.9 vs left 98.2, p=0.29). Flexion and extension strength were significantly increased on the right side (p=0.02, <0.01 respectively). There were significant, weak to moderate correlations between all LQ-YBT scores (components and composite) versus knee flexion strength (r=0.26 to 0.40) (Table 2). Left knee extension strength was weakly correlated to left anterior and posteromedial component scores (r=0.24, 0.34 respectively), as well as the left composite score (r=0.29). Right knee extension strength was only correlated to the right posteromedial component score (r=0.21) and the right composite score (r=0.22). Conclusion: Weak to moderate relationships exist between both component and composite LQ-YBT scores and knee strength. The strongest correlations were found between the LQ-YBT composite scores and knee flexion strength. LQ-YBT composite scores were relatively high, indicating a low chance of injury while differences were seen in knee strength between legs. Future injury prevention programs would benefit from utilizing both tools as the Y-Balance test evaluates motor control and isokinetic strength identifies muscular imbalance, both of which are important in reducing future injury risk.

Original languageEnglish (US)
JournalOrthopaedic Journal of Sports Medicine
Issue number7_suppl3
StatePublished - 2021

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


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