Adaptations to 4-s Sprint Interval Training at Different Intensities

Background Sprint interval training (SIT) is a well-established method for improving cardiovascular and anaerobic performance. While most research focuses on all-out efforts, less is known about the effects of submaximal sprint intensities on these adaptations. This study examined how training at 50%, 75%, and all-out (85%) of maximal anaerobic power (Pmax) influences aerobic capacity and anaerobic power over an 8-week training period. Methods Participants: 24 recreationally active adults (12 females, 12 males) were randomly assigned to one of three training groups: 50% Pmax 75% Pmax All-out (85% Pmax) Training Protocol: Participants completed three sessions per week for eight weeks. Each session consisted of thirty 4-second sprints on a cycling ergometer, totaling 10 minutes per session. Measurements: Peak oxygen consumption (VO₂peak) and maximal anaerobic power (Pmax) were assessed before and after the training program.