Does vibration counteract the static stretch-induced deficit on muscle force development?

Abstract

Objectives: To determine the residual acute vibration-stretching effect on preactivation levels, short-latency stretch reflex, and performance during execution of drop jumps.

Design: Repeated measures.

Methods: Eleven male recreational athletes performed a set of three 45cm drop jumps before and immediately after a 30s static stretching exercise with and without simultaneously imposed muscle vibration (45Hz, 5mm). Drop jump height, ground reaction forces and electromyographic data including Vastus Lateralis onset/levels of preactivation and short-latency stretch reflex were recorded.

Results: No changes were induced on drop jump height. However, stretching-induced decrements on ground reaction force peak and time to peak as well as an increment in contact time followed a delay in short-latency stretch reflex onset and a reduced preactivation level of Vastus Lateralis. Otherwise, when vibration was simultaneously imposed, there was no evidence of changes in high-speed force production variables or electromyographic recordings.

Conclusions: Mechanical vibration, when applied simultaneously to static-stretching routines, appeared to be effective to counteract decreased musculotendinous unit stiffness-induced high-speed force production deficit during jumping performance.

Keywords: Athletic performance; Electromyography; Hypergravity; Plyometrics; Stretch reflex.