Neuromuscular electrical stimulation affects the change in stretch tolerance by static stretching

Area of Science:

• Neuromuscular electrical stimulation
• Biomechanics
• Rehabilitation

Background:

• Neuromuscular electrical stimulation (NMES) affects motor unit activation through stimulation parameters and electrode placement.
• Understanding NMES effects on neural pathways and muscle responses is crucial for optimizing therapeutic interventions.

Purpose of the Study:

• To compare the acute effects of NMES applied over the nerve trunk versus the muscle belly on range of motion and passive torque during static stretching.
• To investigate how NMES influences stretch tolerance and muscle-tendon unit stiffness.

Main Methods:

• NMES was applied to the tibial nerve or triceps surae (60 trains, 10s ON/10s OFF, 10 Hz).
• Passive ankle dorsiflexion was measured before and after NMES or prolonged resting interventions.
• Stretch tolerance and muscle-tendon unit stiffness were assessed via passive torque measurements.

Main Results:

• Increases in maximal dorsiflexion angle did not significantly differ across NMES (nerve/muscle) and resting groups.
• Decreases in muscle-tendon unit stiffness were not significantly different among the groups.
• Significant increases in stretch tolerance were observed with NMES over the nerve trunk and muscle belly, but not with prolonged resting.

Conclusions:

• NMES tends to enhance stretch tolerance during static stretching, irrespective of whether electrodes are placed over the nerve trunk or muscle belly.
• NMES may be a beneficial adjunct to static stretching for improving flexibility and reducing muscle stiffness.
• Further research could explore optimal NMES parameters for maximizing flexibility gains.