Skeletal muscle oxygenation during cycling at different power output and cadence.

Lisha Shastri,Koji Ishida,Mariana Alkhalil,Tina El-Wadi,Claire Forbes,Gerrard Rafferty,Federico Formenti

doi:10.14814/phy2.13963

Abstract

The selection of cadence during cycling may be determined by a number of factors, including the degree of oxygenation in the exercising skeletal muscle. The purpose of this study was to determine the degree of muscle oxygenation associated with different cycling cadences and exercise intensities, and its putative role in the choice of self‐selected cadence during cycling. We recorded cardiopulmonary and metabolic responses to cycling at exercise intensities of 70% and 90% of the ventilatory threshold (T vent), and used near‐infrared spectroscopy to determine tissue saturation index as a measure of skeletal muscle (vastus lateralis) oxygenation. Twelve participants cycled at cadences of 30, 50, 70, 90, and 110 revolutions per minute (rpm), each for 4 min, in a randomized sequence, interspersed with active recovery periods. Despite cardiopulmonary and metabolic responses being greater at 90% than at 70% T vent, and at 110 rpm compared with lower cadences, vastus lateralis oxygenation was not different between the two exercise intensities and five cadences tested. Our results indicate that skeletal muscle tissue saturation index is not substantially affected during cycling for short periods of time at constant, moderate exercise intensity at cadences between 30 and 110 rpm, suggesting that skeletal muscle oxygenation may not be an important negative feedback signal in the choice of self‐selected cadence during cycling at moderate exercise intensity.

Highlights

Despite bicycles allowing a wide choice of gears, selfselected cadences are not necessarily the most energy efficient (Hansen et al 2002; Whitty et al 2009) in noncyclists
Our results indicate that skeletal muscle tissue saturation index is not substantially affected during cycling for short periods of time at constant, moderate exercise intensity at cadences between 30 and 110 rpm, suggesting that skeletal muscle oxygenation may not be an important negative feedback signal in the choice of self-selected cadence during cycling at moderate exercise intensity
This study shows that mean tissue saturation index (TSI) and TSI oscillations within pedal revolution were not different at cycling exercise intensities of 70% and 90% the ventilatory threshold (Tvent), and they did not vary in response to changes in cadence

Summary

Introduction

Despite bicycles allowing a wide choice of gears, selfselected cadences are not necessarily the most energy efficient (Hansen et al 2002; Whitty et al 2009) in noncyclists. A number of physiological, biomechanical, and psychological factors determine the selection of cadence, with exercise duration and intensity, energy cost, neuromuscular fatigue, joint moments, and comfort all having an effect (Takaishi et al 1996; Marsh et al 2000; Whitty et al 2009). The factors, or interaction of factors responsible for the selection of cadence have been investigated extensively, but are not yet fully understood (Ansley and Cangley 2009; Vercruyssen and Brisswalter 2010). Cardiorespiratory responses may be important in the selection of cadence.

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Conclusion