Sex-related differences in joint-angle-specific hamstring-to-quadriceps function following fatigue.

Area of Science:

• Sports Science
• Exercise Physiology
• Biomechanics

Background:

• Muscle function and fatigue resistance can differ between sexes.
• Understanding sex-related differences in muscle fatigue is crucial for injury prevention.
• The hamstring-to-quadriceps (H/Q) functional ratio is an indicator of muscle balance.

Purpose of the Study:

• To investigate the impact of fatiguing exercise on sex-related differences in hamstring and quadriceps muscle function.
• To analyze these effects across various angular velocities and joint angles.

Main Methods:

• An isokinetic assessment was performed on 100 physically active participants (50 males, 50 females).
• Concentric and eccentric torques of knee extensors and flexors were measured at 60°/s, 180°/s, and 300°/s.
• The H/Q functional ratio was calculated using peak torque values at specific knee flexion angles (15°, 30°, 45°).

Main Results:

• Fatiguing exercise decreased H/Q functional ratios in both males and females across all tested conditions.
• Females exhibited significantly greater reductions in H/Q ratios compared to males following fatigue.
• Significant sex-based differences in H/Q ratios were observed post-fatigue at all joint angles and velocities.

Conclusions:

• Fatiguing exercise reveals significant sex-related differences in hamstring and quadriceps muscle function.
• Females demonstrate a lower fatigue resistance in their H/Q functional ratio compared to males.
• This imbalance may increase injury risk in females, especially when fatigued, necessitating targeted interventions for female athletes.