Journal of Trainology



July 2015; Vol. 4, No. 2: Pages 32-36

Relationships between lower body muscle structure and maximal power clean performance

John J McMahon, Aaron Turner, Paul Comfort


Objectives: Correlational studies have linked distinct characteristics of lower body muscle structure (e.g. muscle thickness and pennation angle) to key variables attained during various tasks (e.g. squatting and jumping) which are beneficial to athletic development. The aim of this study was to explore relationships between lower body muscle structure and one-repetition maximum (1-RM) power clean. Design and Methods: 15 resistance trained subjects (13 males, 2 females) had three ultrasound images of their vastus lateralis (VL) and medial gastrocnemius (MG) musculature taken at rest before participating in a 1-RM power clean protocol on two occasions interspersed by 48-72 hours. Results: Intraclass correlation coefficients (ICC) demonstrated high within- and between-image reliability for the muscle structure measures (ICC ≥ 0.81, p < 0.001) and excellent between-session reliability for both the absolute and relative 1-RM power clean measurements (ICC = 0.96, p < 0.001). Significant moderate relationships were found between VL muscle thickness and relative 1-RM power clean (r = 0.506, p = 0.027), MG muscle thickness and absolute 1-RM power clean (ρ = 0.476, p = 0.036) and MG pennation angle and relative 1-RM power clean (ρ = 0.543, p = 0.018). Conclusion: Results suggest that developing thickness of the knee extensor musculature and both thickness and pennation angles of the plantar flexor musculature may augment 1-RM power clean performance. As suggested by previous research, this can be achieved by completing heavy resistance (i.e. strength) training with emphasis placed on improving both the magnitude and rate of lower body force development.

Received June 13, 2015; accepted July 13, 2015