Neural and Mechanical Adaptations During Static Stretching With Different Amplitudes.

Area of Science:

• Neuromechanics
• Exercise Physiology
• Biomedical Engineering

Background:

• Prolonged static stretching is common, but its effects on neural and mechanical properties at different amplitudes remain unclear.
• Understanding these adaptations is crucial for optimizing stretching protocols for performance and injury prevention.

Purpose of the Study:

• To investigate the neural and mechanical responses to prolonged static stretching at submaximal and supramaximal amplitudes.
• To examine the progression of these responses during stretching and their immediate post-stretching alterations.

Main Methods:

• Thirteen healthy adults underwent three randomized sessions: control, 15-min submaximal stretching (ROMmax-5°), and 15-min supramaximal stretching (ROMmax+5°).
• Measurements included spinal excitability (Hmax/Mmax), evoked contractile properties (PTT), voluntary strength (MVC), passive torque, and maximal range of motion (ROMmax).
• Assessments were taken at baseline, during stretching (0, 5, 10, 15 min), and immediately post-stretching.

Main Results:

• Spinal excitability initially decreased then progressively increased during stretching, with greater increases in the supramaximal condition.
• Passive torque increased, but declined and stabilized earlier in the supramaximal group.
• Both stretching protocols reduced MVC and PTT, while improving ROMmax, with slightly greater ROMmax gains in the supramaximal condition.

Conclusions:

• Static stretching amplitude significantly modulates neuromechanical adaptations.
• Both stretching protocols enhance flexibility but reduce voluntary strength.
• Supramaximal stretching may offer slightly greater range of motion improvements, alongside distinct spinal excitability patterns.