Time-of-day and warm-up durations effects on thermoregulation and anaerobic performance in moderate conditions

Abstract

The purpose of this investigation was to assess the effects of different active warm-up (AWU) durations on the diurnal variations of temperature and power output during the Wingate test. Eleven physical education students underwent the Wingate test at 08:00 and 18:00 h after four AWU protocols: control warm-up (CWU), 5 min (AWU₅), 15 min (AWU₁₅), and 20 min (AWU₂₀). The CWU consisted of 5 min of free pedaling; however, the AWU₅, AWU₁₅, and the AWU₂₀ protocols consisted of pedaling at a constant pace of 60 rpm against at 50% of the maximal aerobic power. Oral temperature was recorded at rest, at the end of warm-up, and before and after the Wingate test. The temperature has improved significantly from morning to evening. However, the increase was greater after AWU₁₅ and AWU₂₀. The power peak and the power means were significantly higher in the evening in comparison with morning. These diurnal variations persisted after all AWU durations. However, the increase was greater in the morning and in the evening following the AWU₁₅ in comparison with the AWU₅ and the AWU₂₀. The fatigue index (FI) recorded in the evening is statistically higher in comparison with those recorded in the morning. In addition, our findings show an effect of the AWU durations on the FI. In moderate conditions, an AWU of 15 min at 50% of the maximal aerobic power is the best duration for the improvement of both core temperature and muscle power in the morning and in the evening.

Keywords:

• active warm-up
• anaerobic load
• diurnal variation
• temperature

Acknowledgements

The authors thank the medical staff of the Department of National Center of Medicine and Science in Sports (Sfax) for their technical assistance and the participants for their dedication to the study. They would like to express their appreciation to Dr Hamdi Chtourou for editing and improving the manuscript. The authors have no conflicts of interest that are directly relevant to the contents of this manuscript.