Immediate effects of passive stretching and/or local vibration on ankle range of motion, calf muscle stiffness and passive torque: a randomized controlled cross-over trial.

Abstract

Purpose: Vibrational stimulation was suggested sufficient to acutely enhance range of motion (ROM). However, the actual merit of superimposed vibration and underlying mechanical or sensory mechanisms of ROM increases due to local vibration are not well understood.

Methods: Using a randomized controlled cross-over trial, this study opposed two minutes of stretching + vibration (STV) to vibration (V) and stretching (ST) alone as well as a passive control (CG) in 30 healthy, recreationally active participants. Pre- and post-intervention measurements of ankle dorsiflexion ROM, ankle passive torque, and gastrocnemius medialis muscle stiffness were conducted using a dynamometer and shear wave elastography, respectively.

Results: All interventions significantly increased ROM (p < 0.001, η² = 0.622) compared to CG, with no additional benefits observed for vibration combined with stretching compared to stretching or vibration alone. However, combining stretching and vibration produced the most pronounced reductions in passive torque over the whole ankle ROM. The combination demonstrated additive effects of stretching and vibration, which affected passive torque in the end ROM and at rest, respectively. Muscle stiffness decreased, but did not differentiate between conditions.

Conclusion: These findings negate additional acute vibration effects on ROM that surpass the effects of stretching alone, while the combination of stretching and vibration presented the most prominent influence on passive torque and joint resistance. Vibration also increases stretching pain tolerance; this might facilitate the conduction of exercises and improves compliance as well as adherence to stretching habits.