Static stretching increases muscle fatigue during submaximal sustained isometric contractions

Area of Science:

• Exercise Physiology
• Neuromuscular Function
• Sports Science

Background:

• Static stretching is commonly used to improve flexibility.
• Its acute effects on neuromuscular fatigue are not fully understood.
• Understanding these effects is crucial for optimizing training and performance.

Purpose of the Study:

• To investigate the immediate impact of static stretching on neuromuscular fatigue.
• To assess changes in electromyography (EMG) signals in forearm muscles (flexor carpi radialis and flexor digitorum) after stretching.
• To compare these effects against a control condition without stretching.

Main Methods:

• Twenty-six healthy men performed isometric handgrip fatigue tests.
• Tests were conducted before and after a static stretching protocol on the dominant hand.
• A control limb underwent tests without stretching; electromyography (EMG) measured root mean squares (RMS) and mean frequency (MF).

Main Results:

• Static stretching significantly increased the rate of EMG activity increase in both flexor carpi radialis (FC) and flexor digitorum (FD).
• A significant higher rate of decrease in mean frequency (MF) was observed for FC and FD post-stretching.
• No significant differences were found in the control limb, indicating stretching-specific effects.

Conclusions:

• Static stretching immediately preceding submaximal isometric contractions may enhance neuromuscular fatigue.
• This suggests a potential reduction in muscle endurance capacity following acute static stretching.
• Further research is needed to explore long-term implications and optimal stretching protocols.