Comparison of four local vibratory stimuli on mechanical and sensorial variables related to muscle‐tendon unit response

Abstract

It is still unclear what is the optimum local vibration stimulus (LV) configuration to generate a greater range of motion gain (ROM) and how LV affects the mechanical and sensory responses of the skeletal muscles. This study aimed to compare the acute effects of four LV configurations on mechanical and sensorial variables related to the muscle‐tendon unit response to stretching. Ten male volunteers were randomly undertaken to four LV configurations (LV1: 14 Hz and 3 mm, LV2: 24 Hz and 3 mm, LV3: 14 Hz and 6 mm, and LV4: 24 Hz and 6 mm) at the right hamstrings muscles, and one non‐vibration condition (control). Maximum ROM (ROMMAX) and torque (TORMAX), and their respective values at the first sensation of tightness (FSTROM and FSTTOR) during stretching maneuvers were measured with an isokinetic dynamometer. Passive stiffness (PS) was calculated as the slope of torque vs. angle time‐series. Repeated measures ANOVA revealed differences between the post‐test and pre‐test values (delta) for the ROMMAX and FSTROM between each local vibration condition compared with the control group (P < .05), with no differences among them (P > .05). The four LV configurations were equally able to improve the ROMMAX and FSTROM, being the LV4 the one that produced higher ROMMAX in 40% of the participants.