Corticomotor excitability of gluteus maximus and hip extensor strength: The influence of sex

Abstract

Purpose: To compare hip extensor strength and corticomotor excitability (CME) of gluteus maximus (GM) between males and females. A secondary purpose was to determine if CME of GM is predictive of hip extensor strength.

Method: Thirty-two healthy individuals participated (15 males and 17 females). CME of GM was assessed using the input-output curve (IOC) procedure acquired from transcranial magnetic stimulation (average slope). Hip extensor strength was measured by a dynamometer during a maximal voluntary isometric contraction. Independent t-tests were used to compare CME of GM and peak hip extensor torque between males and females. Linear regression analysis was used to determine whether peak hip extensor torque was predicted by CME of GM.

Result: Compared to males, females demonstrate lower peak hip extensor torque (4.42 ± 1.11 vs. 6.15 ± 1.72 Nm/kg/m2, p < 0.01) and lower CME of GM (1.36 ± 1.07 vs. 2.67 ± 1.30, p < 0.01). CME of GM was a significant predictor of peak hip extensor torque for males and females combined (r² = 0.36, p < 0.001).

Conclusion: Our findings support the premise that corticomotor excitability plays a role in the ability of a muscle to generate torque.

Keywords: Hip extensor torque; Input-output curve; Knee injury; Transcranial magnetic stimulation.