Effects of Different High-Intensity Interval Training Protocols on Physiological and Skeletal Muscle Adaptations in Healthy Young Men

Participants completed a two-week cycling sprint interval training program comprising six sessions (three sessions per week). The protocol involved repeated 10-second maximal cycling sprints separated by 60-second recovery intervals.

A two-week cycling sprint interval training intervention consisting of six sessions performed three times per week. Participants performed repeated 10-second maximal cycling sprints interspersed with 60-second recovery intervals.

Participants completed a two-week cycling sprint interval training program comprising six sessions (three sessions per week). The protocol involved repeated 10-second maximal cycling sprints separated by 240-second recovery intervals.

A two-week cycling sprint interval training intervention consisting of six sessions performed three times per week. Participants performed repeated 10-second maximal cycling sprints interspersed with 240-second recovery intervals.

Participants completed a two-week high-intensity interval cycling program consisting of six supervised training sessions (three sessions per week). Each session included six 90-second cycling bouts performed at 80% of maximal aerobic power, separated by 180-second passive recovery intervals. Exercise cadence was maintained at approximately 60 revolutions per minute.

A two-week cycling high-intensity interval training intervention comprising six supervised sessions performed three times per week. Each session consisted of six 90-second exercise bouts at 80% of maximal aerobic power, separated by 180-second passive recovery intervals. Cycling cadence was approximately 60 revolutions per minute.

Participants completed a two-week sprint interval training program comprising six cycling sessions (three sessions per week). The intervention consisted of repeated 30-second all-out cycling sprints performed using a Wingate-based protocol, with recovery periods between successive efforts.

A two-week cycling sprint interval training intervention comprising six sessions performed three times per week. Participants performed repeated 30-second all-out cycling sprints using a Wingate-based protocol, with recovery intervals between successive sprints.

Change in maximal oxygen uptake (VO2max), expressed in mL/kg/min, assessed using an incremental exercise test before and after the two-week training intervention.

Changes in cognitive performance assessed using the Stroop Color-Word Test (inhibitory control), Trail Making Test (processing speed and executive function), and Digit Span Test (working memory), before and after the two-week training intervention.

Changes in skeletal muscle oxidative enzyme activity assessed in biopsy samples collected before and after the two-week training intervention. Muscle biopsies were performed in a subset of participants who provided additional informed consent for the procedure.