Fatigue affects peak joint torque angle in hamstrings but not in quadriceps

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Fatigue significantly impacts neuromuscular function in athletes.
• Understanding muscle torque-angle relationships is crucial for injury prevention.

Purpose of the Study:

• To examine changes in peak joint torque angle and torque ratios in hamstrings and quadriceps after a soccer match simulation.
• To assess the impact of fatigue on functional (Hecc:Qconc) and conventional (Hconc:Qconc) hamstring-to-quadriceps torque ratios.

Main Methods:

• Twenty-two male amateur soccer players underwent isokinetic strength testing before and after a simulated match.
• Peak torque, peak joint torque angle, and torque ratios were measured at multiple angular velocities (1.05, 3.14, 5.24 rad·s⁻¹).
• Both dominant and non-dominant limbs were evaluated.

Main Results:

• A significant increase in peak joint torque angle was observed in hamstrings (both eccentric and concentric contractions) but not quadriceps.
• Peak torque decreased significantly in both hamstrings and quadriceps.
• The functional Hecc:Qconc ratio decreased in the dominant limb at higher velocities; the conventional Hconc:Qconc ratio remained unchanged.

Conclusions:

• Fatigue alters the hamstring torque-angle relationship, particularly near knee extension, potentially increasing injury risk.
• Greater peak torque decrement in hamstrings compared to quadriceps suggests a higher susceptibility to injury.
• Eccentric training is recommended to mitigate hamstring strain by addressing altered torque production at shorter muscle lengths.