Sex Differences in Correlations Between Muscle Architecture and Impulse in a Heterogenous Group of Athletes

Abstract

BACKGROUND: Previous investigations have identified moderate to strong relationships between skeletal muscle architecture (SMA) and performance measures in athletes, however differences between males and females in this regard are not well known. A better understanding of relationships between task-specific impulse windows and SMA in males and females may allow coaches to direct training stimuli toward improving specific morphological underpinnings of sport performance for the athletes under their care. PURPOSE: The purpose of this analysis was to determine relationships between components of SMA and isometric impulse in male and female athletes. METHODS: Pennation angle (PA), fascicle length (FL), and anatomical cross-sectional area (ACSA) were determined for the vastus lateralis muscle via β-mode ultrasonography in a group of male (n = 94) and female (n = 61) collegiate, club, and international athletes. Net isometric impulse at 50, 90, 200, and 250 ms was measured during an isometric mid-thigh pull (IMTP) test administered pre-season as part of an ongoing athlete monitoring program. RESULTS: Pearson product-moment correlation revealed weak correlations between FL and impulse in males (r = 0.33 to 0.36, p < 0.05) but not in females, weak correlations between CSA and impulse in males (r = 0.39 to 0.48, p < 0.05), and weak to moderate correlations between CSA and impulse in females (r = 0.55 to 0.62, p < 0.05). CONCLUSIONS: These results indicate that there may be sex-based differences in the physiological underpinnings of impulse generation in trained athletes, particularly in relation to both muscle size and fascicle length of the vastus lateralis. Further research should investigate changes in these relationships over time and consider contributions from neuromuscular components.