Abstract
This study aimed to examine the energy metabolic profile in different types of sub-sprint interval training (SubSIT), varying exercise intensities, durations, and rest durations. SubSIT was defined as interval training performed at an intensity greater than 120 %V ̇O2max but below maximal effort. Nine competitive male track and field athletes performed an incremental sprint interval test to determine an intensity index and a submaximal incremental exercise test to estimate oxygen deficit during SubSIT. These were followed by four different types of SubSIT with different combinations of exercise intensity, duration, and rest duration. The total anaerobic energy supply during SubSIT was greater than values reported in a previous study. The anaerobic energy ratio in SubSIT significantly decreased with successive repetitions, even across the four different types of SubSIT. SubSIT performed at higher intensity, shorter exercise duration, and longer rest duration showed significantly higher anaerobic energy ratios. Moreover, SubSIT with a greater number of repetitions led to significantly greater total anaerobic energy supply. These findings suggest that SubSIT provides a considerable strain on anaerobic metabolism. Among the different types of SubSIT, conditions that allowed for a higher number of repetitions suggested a greater total anaerobic energy supply. In particular, exercise duration and rest duration were also suggested to have a significant influence the anaerobic energy ratio, with shorter exercise or longer rest durations promoting greater contribution from anaerobic metabolism.