Sex-related differences in joint-angle-specific functional hamstring-to-quadriceps strength ratios

Area of Science:

• Biomechanics
• Sports Medicine
• Human Physiology

Background:

• Muscle strength imbalances, particularly quadriceps dominance, are linked to knee injuries.
• The hamstrings eccentric-to-quadriceps concentric functional ratio (H/Q FUNC) is a key indicator of muscle balance.
• Understanding sex-related differences in H/Q FUNC is crucial for injury prevention.

Purpose of the Study:

• To compare sex-related differences in hamstring and quadriceps muscle function.
• To analyze the isokinetic hamstrings eccentric-to-quadriceps concentric functional ratio (H/Q FUNC) between males and females.
• To investigate the influence of angular velocity and joint angle on H/Q FUNC.

Main Methods:

• Fifty males and 46 females underwent isokinetic assessments for knee extension and flexion.
• Peak torque and joint-angle-specific torque values were measured at three angular velocities.
• The H/Q FUNC was calculated and analyzed using repeated measures ANOVA.

Main Results:

• H/Q FUNC was significantly affected by angular velocity, joint angle, and sex (p < 0.01).
• H/Q FUNC decreased with increasing movement velocity and proximity to full knee extension.
• Females demonstrated a significantly lower H/Q FUNC compared to males across all conditions.

Conclusions:

• H/Q FUNC assessment near full knee extension is more informative for injury risk than peak torque.
• Preventive and rehabilitation programs should focus on reducing quadriceps dominance.
• Enhancing eccentric hamstring strength, especially in females, is vital for injury reduction.