Salivary endocrine response following a maximal incremental cycling protocol with local vibration.

Monèm Jemni,Amy Tanner,Qiuli Hu,Fabien A Basset,Anne Delextrat,Bessem Mkaouer,Huiyu Zhou,Yaodong Gu,Ferman Konukman,Michel Marina

doi:10.1371/journal.pone.0238051

Abstract

The aim of this study was to compare the effects of vibration (Vib versus noVib) during a maximal graded cycling exercise on hormonal response, precisely on cortisol (C) and testosterone (T). Twelve active males (25 ± 5yrs; 181 ± 5cm; 80.7 ± 11.1kg) randomly performed two maximal incremental cycling tests on two separate days and at the same time of the day (09:00). The protocol consisted of incremental steps of 3 min duration performed on a PowerBIKETM that induces vibration cycling. The study was a repeated measures design and participants performed the test with and without vibration. Gas exchange and heart rate (HR) were continuously assessed and blood lactate (Bla) was recorded at the end of each incremental stage. Saliva samples were collected before and immediately after the test, and analysed for (C) and (T).The results show that C and T increased in both cycling conditions; however, the C’s magnitude of change was significantly higher by 83% after Vib cycling in comparison to the no Vib (p = 0.014), whereas the T’s magnitude of change were not statistically different between trials (p = 0.715). Vibration induced a decrease of the T/C ratio (p = 0.046) but no significant changes were observed following noVib (p = 0.476). As a conclusion, the investigation suggests that adding mechanical vibration to cycling may potentiate a catabolic exercise-induced state, which could have potential clinical implications in rehabilitation and injury treatment. Sport experts should take this message home to carefully plan the recovery process and time during training and competitions.

Highlights

Local body vibration (LBV) during dynamic activity has only recently been applied to cycling exercise
Endocrine response to vibration cycling exercise duration compared to cycling-only trials [1]
Note that there is a difference between whole body vibration exercise/training using platforms in comparison to vibration cycling which is the context of this study

Summary

Introduction

Local body vibration (LBV) during dynamic activity has only recently been applied to cycling exercise. More recent and meticulously controlled trials have indicated no differences in cardiorespiratory and metabolic variables between vibration cycling and cycling-only exercises, except a higher ventilation in favour of the vibration cycling [2]. These recent finding did not confirm prior studies who suggested higher rates of oxygen uptake, possibly due to vibration-induced activation of afferent neurons causing contraction of inactive muscle fibres [1, 3]. Whole body vibration exercise showed consistent significant improvement of muscles’ viscoelasticity and flexibility [4] whereas studies investigating its effect on strength are not unanimous, with some showing positive effects [4,5,6] and others showing the opposite [7] or no effect [4, 8]

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