Metabolic Consequences of Resistive Force Selection During Cycle Ergometry Exercise

Difference in total workload during sprint interval training for adults living with or without obesity

PURPOSE

The primary objective of the study was to compare the implications of body composition on work volume, power outputs (peak, mean, and minimum), and relative drop load throughout 4 weeks of sprint interval training (SIT) in individuals living with and without obesity.

METHODS

Thirty-four participants living with (n = 16) and without (n = 18) obesity took part in 12 sessions of SIT over 4 weeks. SIT consisted of repeated 30-s Wingate with a drop load of 7.5% of the participant's body mass separated by 4 min of active recovery. Fat-free mass was estimated using a BOD POD. Work volume, drop load, and power output (peak, mean, and minimum) relative to body mass and fat-free mass were calculated using a Monark 874E Weight cycle ergometer.

RESULTS

Individuals living with obesity had a significantly larger drop load relative to fat-free mass (p < 0.001) and absolute drop load (p < 0.001) as well as a lower cycling cadence (p < 0.001) compared to individuals without obesity. No significant difference was observed in work volume (p = 0.167) as well as mean (p = 0.903), peak (p = 0.294), and minimum (p = 0.103) power relative to fat-free mass between groups.

CONCLUSION

The findings suggest that individuals living with obesity work at a higher relative drop load when utilizing a percentage of body mass; however, a reduced cycling cadence results in similar total work volume throughout SIT.

Effect of time of day on aerobic contribution to the 30-s Wingate test performance

The purpose of this study was to evaluate the effects of time of day on aerobic contribution during high-intensity exercise. A group of 11 male physical education students performed a Wingate test against a resistance of 0.087 kg . kg(-1) body mass. Two different times of day were chosen, corresponding to the minimum (06:00 h) and the maximum (18:00 h) levels of power. Oxygen uptake (.VO(2)) was recorded breath by breath during the test (30 sec). Blood lactate concentrations were measured at rest, just after the Wingate test, and again 5 min later. Oral temperature was measured before each test and on six separate occasions at 02:00, 06:00, 10:00, 14:00, 18:00, and 22:00 h. A significant circadian rhythm was found in body temperature with a circadian acrophase at 18:16+/-00:25 h as determined by cosinor analysis. Peak power (P(peak)), mean power (P(mean)), total work done, and .VO(2) increased significantly from morning to afternoon during the Wingate Test. As a consequence, aerobic contribution recorded during the test increased from morning to afternoon. However, no difference in blood lactate concentrations was observed from morning to afternoon. Furthermore, power decrease was greater in the morning than afternoon. Altogether, these results indicate that the time-of-day effect on performances during the Wingate test is mainly due to better aerobic participation in energy production during the test in the afternoon than in the morning.