This randomized controlled trial evaluated the effects of a 6-week supervised sprint interval training program on cardiorespiratory fitness in healthy sedentary young adults. Forty participants aged 20 to 25 years were randomly assigned to either a sprint interval training group or a control group. The sprint interval training group completed supervised cycle-ergometer sessions three times per week for 6 weeks, while the control group maintained their usual sedentary routine. The primary outcome was maximal oxygen uptake (VO2max). Secondary outcomes included resting heart rate and 6-minute walk test distance. The study aimed to determine whether a short-term, time-efficient sprint interval training program could improve cardiovascular capacity and functional exercise performance in sedentary young adults.

This study was designed as a randomized controlled pre-test and post-test intervention study. Healthy sedentary adults aged 20 to 25 years were enrolled after ethics approval and written informed consent. Participants were randomly allocated in a 1:1 ratio to either a supervised sprint interval training group or a control group.

The sprint interval training group performed supervised exercise sessions on a cycle ergometer three times per week for 6 weeks. Each session included a 5-minute warm-up, followed by repeated 30-second all-out sprint bouts with active recovery periods. The number of sprint repetitions was progressively increased during the intervention period. The control group maintained their usual sedentary lifestyle and did not receive an additional exercise program.

Outcome measurements were performed before and after the intervention. The primary outcome was VO2max, assessed using a maximal exercise test on a cycle ergometer with respiratory gas analysis. Secondary outcomes were resting heart rate and 6-minute walk test distance. Adherence and adverse events were monitored throughout the study period.

Inclusion Criteria:

• Aged 20-25 years
• Healthy sedentary adult
• Engaging in less than 150 minutes/week of moderate-to-vigorous physical activity
• IPAQ score below 600 MET-min/week or not participating in a regular exercise program
• Willing to provide written informed consent

Exclusion Criteria:

• History of cardiovascular, pulmonary, or metabolic disease, such as hypertension or diabetes
• Musculoskeletal injury or orthopedic condition preventing exercise participation
• Pregnancy or breastfeeding
• Smoking
• Regular medication use

No masking was used because participants and research staff were aware of the exercise-training intervention.