Muscle activation and length changes during two lunge exercises: implications for rehabilitation

Area of Science:

• Biomechanics
• Exercise Physiology
• Rehabilitation Science

Background:

• Eccentric exercises are vital for treating muscle and tendon injuries.
• Complex movements like forward lunges present challenges in identifying specific muscle contractions.
• Understanding muscle activation during lunges is essential for effective rehabilitation protocols.

Purpose of the Study:

• To identify the types of muscle contractions occurring during walking and jumping forward lunges.
• To analyze the timing of isometric, concentric, and eccentric activations in key lower limb muscles.
• To assess the implications of these findings for physical rehabilitation strategies.

Main Methods:

• Five experienced athletes performed walking and jumping forward lunges.
• Motion analysis tracked muscle length changes via origin and insertion points.
• Electromyography recorded muscle activity (lateral hamstrings, rectus femoris, lateral gastrocnemius) alongside motion data.

Main Results:

• Eccentric contractions were identified in the quadriceps and gastrocnemius muscles during the forward lunge.
• No eccentric contractions were observed in the hamstrings.
• Hamstrings demonstrated isometric contractions during the initial stance phase of the lunge.

Conclusions:

• Forward lunges utilize eccentric contractions in the quadriceps and gastrocnemius, beneficial for rehabilitation.
• The absence of hamstring eccentric activity suggests specific training modifications may be needed.
• This study clarifies muscle function during lunges, informing targeted rehabilitation programs for muscle injuries.