Immediate effects of localized vibration on flexibility: A randomized crossover trial

Area of Science:

• Biomechanics and Exercise Physiology
• Musculoskeletal Ultrasound Imaging

Background:

• Localized vibration (LV) is a potential method to enhance flexibility, but its efficacy compared to conventional static stretching (SS) is not well-established.
• Understanding the immediate effects of LV on muscle properties is crucial for optimizing training protocols.

Purpose of the Study:

• To compare the immediate effects of short-duration LV and SS on lower limb flexibility in healthy individuals.
• To utilize advanced muscle ultrasound (MUS) techniques, including three-dimensional shear wave elastography (3D-SWE) and Doppler MUS, for objective assessment.

Main Methods:

• A randomized crossover trial with a same-subject design involving 14 healthy participants.
• Interventions included 1 minute of LV (30 Hz, 3 mm amplitude) or SS applied to bilateral crural muscles.
• Muscle elasticity and blood flow were assessed using 3D-SWE and Doppler MUS, alongside a stand-and-reach test.

Main Results:

• Both LV and SS reduced flexibility, but LV resulted in a significantly smaller decrease compared to SS.
• LV significantly increased the power Doppler index (PDI) and decreased shear wave elastography (SWE) values in the gastrocnemius muscle, indicating altered muscle elasticity.

Conclusions:

• Localized vibration may offer a more effective approach than static stretching for improving immediate lower limb flexibility.
• 3D-SWE and Doppler MUS are valuable tools for objectively assessing muscle condition and elasticity changes post-intervention.