Effects of acute passive stretching on ventilatory pattern during prolonged cycle exercise

Abstract

Passive stretching, by inducing mechanical and chemical stimuli that activate receptors on the terminal end of group III and IV nerve fibres located within joints and muscle, may increase ventilation \((\dot VE)\)) during exercise. The aim of the study was to assess the effects of an acute bout of passive stretching on the ventilatory pattern. Maximum oxygen uptake was determined in nine participants who then performed a sustained cycle exercise of high intensity (constant workload of 85% of the minimum power to elicit maximum oxygen uptake, \(\dot W_{85} \)) with and without previous stretching. During the tests metabolic and respiratory parameters were recorded breath-by-breath. Time to exhaustion in the \(\dot W_{85} \) test was significantly shorter (−29%) with stretching. During the first 12 min of exercise the following parameters were significantly higher with stretching than without: oxygen uptake (+4%), ventilation (+9%), respiratory muscle power (+16%) and respiratory muscle oxygen uptake (+13%; P < 0.05). The increase in ventilation was accompanied mainly by an increase in respiratory frequency rather than in tidal volume. However, after stretching the metabolic rate also increased. Thus, the higher ventilation might have been a consequence of both higher muscle afferent activation and higher metabolic rate. Stretching alters the respiratory and metabolic response to exercise, but its effects on ventilation need further investigation.