Abstract
Introduction: Asynchronous arm-cranking performed at high cadences elicits greater cardiorespiratory responses compared to low cadences. This has been attributed to increased postural demand and locomotor-respiratory coupling (LRC), and yet, this has not been empirically tested. This study aimed to assess the effects of cadence on cardiorespiratory responses and LRC during upper-body exercise.Methods: Eight recreationally-active men performed arm-cranking exercise at moderate and severe intensities that were separated by 10 min of rest. At each intensity, participants exercised for 4 min at each of three cadences (50, 70, and 90 rev min-1) in a random order, with 4 min rest-periods applied in-between cadences. Exercise measures included LRC via whole- and half-integer ratios, cardiorespiratory function, perceptions of effort (RPE and dyspnoea), and diaphragm EMG using an oesophageal catheter.Results: The prevalence of LRC during moderate exercise was highest at 70 vs. 50 rev min-1 (27 ± 10 vs. 13 ± 9%, p = 0.000) and during severe exercise at 90 vs. 50 rev min-1 (24 ± 7 vs. 18 ± 5%, p = 0.034), with a shorter inspiratory time and higher mean inspiratory flow (p < 0.05) at higher cadences. During moderate exercise, [Formula: see text] and f C were higher at 90 rev min-1 (p < 0.05) relative to 70 and 50 rev min-1 ([Formula: see text] 1.19 ± 0.25 vs. 1.05 ± 0.21 vs. 0.97 ± 0.24 L min-1; f C 116 ± 11 vs. 101 ± 13 vs. 101 ± 12 b min-1), with concomitantly elevated dyspnoea. There were no discernible cadence-mediated effects on diaphragm EMG.Conclusion: Participants engage in LRC to a greater extent at moderate-high cadences which, in turn, increase respiratory airflow. Cadence rate should be carefully considered when designing aerobic training programmes involving the upper-limbs. [ABSTRACT FROM AUTHOR]