Sprint Interval Training and the School Curriculum: Benefits Upon Cardiorespiratory Fitness, Physical Activity Profiles, and Cardiometabolic Risk Profiles of Healthy Adolescents

This study examined the impact of a 4-week school-based sprint interval training program on cardiorespiratoryfitness (CRF), daily physical activity (PA) behavior, and cardiometabolic risk (CMR) outcomes in adolescents. Methods: A totalof 56 adolescents (22 females) were allocated to either an intervention (n = 22; 17.0 [0.3] y) or control group (n = 30; 16.8 [0.5] y).Intervention group performed 5 to 6, 30 second “all out” running sprints, interspersed with 30-second rest intervals, 3 times perweek, for 4 consecutive weeks, whereas control group performed their normal physical education lessons. CRF was estimatedfrom the 20-m multistage fitness test and PA behavior was determined using accelerometry. Fasting blood samples were obtainedto measure biochemical markers of CMR. Results: Significant group × time interactions were observed for CRF (5.03 [1.66 to8.40]; P < .001; d = 0.95), sedentary time (136.15 [91.91 to 180.39]; P = .004; d = 1.8), moderate PA (57.20 [32.17 to 82.23];P < .001; d = 1.5), vigorous PA (5.40 [4.22 to 6.57]; P < .001; d = 1.2), fasting insulin (0.37 [−0.48 to 1.21]; P = .01;d = 1.0), homeostasis model of assessment-insulin resistance (0.26 [0.15 to 0.42]; P < .001; d = 0.9), and clustered CMR score(0.22 [−0.05 to 0.68]; P < .001; d = 10.63). Conclusion: Findings of this study indicate that 4 weeks of school-based sprintinterval training improves CRF, improves PA profiles, and maintains CMR in adolescents during the school term.