Improvements in Hip Extensor Rate of Torque Development Influence Hip and Knee Extensor Feed-Forward Control

Area of Science:

• Biomechanics
• Motor Control
• Exercise Physiology

Background:

• Females often use feedforward control during landing, compensating for reduced hip extensor rate of torque development (RTD) with earlier knee extensor activation.
• Understanding neuromuscular adaptations to targeted training is crucial for optimizing landing mechanics and injury prevention.

Purpose of the Study:

• To investigate the effects of a 4-week hip-focused training program on hip extensor RTD.
• To examine the influence of this training on feedforward control strategies in hip and knee extensors during a drop-jump task.

Main Methods:

• Twenty-one females participated in a 4-week hip extensor strengthening program.
• Pre- and post-training assessments included hip extensor RTD evaluation and electromyographic analysis of hip and knee extensors during a drop-jump landing.
• Analysis focused on changes in RTD and muscle pre-activation timing relative to ground contact.

Main Results:

• Significant improvements in hip extensor RTD were observed post-training (p=0.009).
• Muscle pre-activation occurred significantly closer to ground contact for both hip extensors (p<0.001) and knee extensors (p<0.001).
• A negative correlation was found between improved hip extensor RTD and earlier knee extensor onset (r=-0.48, p=0.03).

Conclusions:

• A 4-week hip-focused training program effectively enhances hip extensor RTD in females.
• Improved hip extensor capacity leads to a shift in feedforward control, reducing reliance on anticipatory knee muscle activation during landing.
• These findings suggest that targeted hip training can modify neuromuscular strategies for improved landing performance.