Relationship between lower limb EMG activity and knee frontal plane projection angle during a single-legged drop jump

Objectives: To assess a relationship between lower limb muscle activity and the frontal plane knee ki-nematics during a single-legged drop jump. Design: Correlation study; Setting: Functional Anatomy Laboratory. Participants: 35 healthy collegiate male athletes. Main outcome measures: Muscle activity (%MVIC) of gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius and lateral gastrocnemius; peak knee frontal plane projection angle; and Pearson's correlation coefficients between muscle activity and peak knee frontal plane projection angle. All outcomes were assessed for both dominant and non-dominant limbs. Results: Significant correlations (r = 0.46-0.60, P < 0.05) were found between the muscle activities of the gluteus maximus, gluteus medius, biceps femoris, and semitendinosus, when compared to the knee frontal plane projection angle. Conclusion: Gluteal muscles and hamstring muscles are associated with the peak knee frontal plane projection angle during a single-legged drop jump test. Thus, gluteal and hamstring muscle activities should be considered when developing rehabilitation or injury prevention programs. (C) 2021 Elsevier Ltd. All rights reserved.