Hip joint load and muscular activation during rising exercises

Area of Science:

• Biomechanics
• Human Movement Analysis

Background:

• Rising exercises are common rehabilitation and training movements.
• Understanding hip joint loading and muscle activation is crucial for injury prevention and performance optimization.

Purpose of the Study:

• To investigate the hip joint load and the activation of key hip extensor muscles during rising exercises.
• To examine the effects of adaptive adjustments on joint load and muscle activity.

Main Methods:

• Nine healthy subjects performed rising exercises with varying trunk inclination and resistance.
• Hip joint load was calculated using force plate data and cine-film analysis.
• Muscle activity was measured using normalized electromyography (EMG) of the gluteus maximus, hamstrings, adductor magnus, and rectus femoris.

Main Results:

• The hip joint loading moment was approximately 45 Nm initially, decreasing with a smaller hip angle.
• Increased backward trunk inclination maintained the load moment but increased muscle activity in the final phase.
• Placing the foot further backward or reducing resistance significantly lowered hip joint load.
• Posterior foot position and increased resistance slightly elevated hip extensor muscle activity.

Conclusions:

• Adaptive strategies like backward foot placement and reduced resistance can effectively decrease hip joint load during rising exercises.
• Trunk inclination influences both joint load and muscle activation patterns.
• These findings provide insights for designing safer and more effective exercise protocols.