Alexis Ortiz1, Carmen E Capo-Lugo2, Heidi L Venegas-Rios3. 1. School of Physical Therapy, Texas Woman's University, 6700 Fannin Street, Houston, TX 77030(∗). Electronic address: aortiz10@twu.edu. 2. Interdepartamental Neuroscience Program, Northwestern University, Chicago, IL(†). 3. Division of Biostatistics, School of Public Health, University of Texas, Houston, TX(‡).
Abstract
OBJECTIVE: To compare landing mechanics and neuromuscular recruitment strategies between women with semitendinosus-gracilis anterior cruciate ligament reconstruction (SG-ACLr) and noninjured women during double- and single-legged drop jumps. DESIGN: Cross-sectional biomechanical study. SETTING: Single university-based biomechanics laboratory. PARTICIPANTS: Fourteen women 1-5 years post-SG-ACLr and 16 noninjured women participated in this study. METHODS: After anthropometric measurements, warm-up, and familiarization procedures, participants performed 5 trials of a double- and single-legged drop jumps. MAIN OUTCOME MEASUREMENTS: Dynamic knee valgus was measured as the distance between knee joints during the landing phase of the double-leg drop jumps. Medial knee displacement was the outcome considered during the landing phase of the single-leg drop jumps. For both drop jump tasks, neuromuscular recruitment was evaluated through rectified normalized electromyographic activity of the quadriceps and hamstrings (amplitude and latency), and quadriceps/hamstrings electromyographic co-contraction ratio. RESULTS: Although the SG-ACLr group demonstrated a tendency toward a greater dynamic knee valgus during both drop jumps, these differences did not reach statistical significance. EMG data revealed different neuromuscular strategies for each group, depending on the specific jump. CONCLUSIONS: These findings suggest that women with SG-ACLr have a tendency toward greater dynamic knee valgus that could predispose to additional knee injuries. Rehabilitation specialists need to be aware of existing kinematic and neuromuscular deficiencies years after SG-ACLr. Taking this into consideration will aid in prescribing appropriate interventions designed to prevent re-injury.
OBJECTIVE: To compare landing mechanics and neuromuscular recruitment strategies between women with semitendinosus-gracilis anterior cruciate ligament reconstruction (SG-ACLr) and noninjured women during double- and single-legged drop jumps. DESIGN: Cross-sectional biomechanical study. SETTING: Single university-based biomechanics laboratory. PARTICIPANTS: Fourteen women 1-5 years post-SG-ACLr and 16 noninjured women participated in this study. METHODS: After anthropometric measurements, warm-up, and familiarization procedures, participants performed 5 trials of a double- and single-legged drop jumps. MAIN OUTCOME MEASUREMENTS: Dynamic knee valgus was measured as the distance between knee joints during the landing phase of the double-leg drop jumps. Medial knee displacement was the outcome considered during the landing phase of the single-leg drop jumps. For both drop jump tasks, neuromuscular recruitment was evaluated through rectified normalized electromyographic activity of the quadriceps and hamstrings (amplitude and latency), and quadriceps/hamstrings electromyographic co-contraction ratio. RESULTS: Although the SG-ACLr group demonstrated a tendency toward a greater dynamic knee valgus during both drop jumps, these differences did not reach statistical significance. EMG data revealed different neuromuscular strategies for each group, depending on the specific jump. CONCLUSIONS: These findings suggest that women with SG-ACLr have a tendency toward greater dynamic knee valgus that could predispose to additional knee injuries. Rehabilitation specialists need to be aware of existing kinematic and neuromuscular deficiencies years after SG-ACLr. Taking this into consideration will aid in prescribing appropriate interventions designed to prevent re-injury.
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