Sprint interval training (SIT) is an effective method to maintain cardiorespiratory fitness (CRF) and glucose homeostasis in Scottish adolescents

Abstract

The present study examined the physiological impact of a school based sprint interval training (SIT) intervention in replacement of standard physical education (SPE) class on cardio-respiratory fitness (CRF) and glucose homeostasis during the semester following summer vacation. Participants (n=49) were randomly allocated to either intervention (SIT; n=26, aged 16.9 ± 0.3 yrs) or control group who underwent standard physical education (SPE; n=23, aged 16.8 ± 0.6 yrs). CRF (VO2max) and glucose homeostasis were obtained prior-to and following 7 weeks of SIT exercise. Significant group x time interaction was observed for CRF (P < 0.01) with non-significant trends for fasting insulin (P= 0.08), and HOMA-IR (P=0.06). CRF decreased (P < 0.01) in SPE such that POST intervention CRF was significantly lower (P< 0.05) in SPE. Fasting plasma glucose (P < 0.01), insulin (P< 0.01) and HOMA-IR (P< 0.01) increased significantly amongst SPE. The main finding of the present study is that 7-weeks of SIT exercise is an effective method of maintaining (but not improving) CRF and fasting insulin homeostasis amongst school-going adolescents. SIT exercise demonstrates potential as a time efficient physiological adjunct to standard PE class in order to maintain CRF during the school term.

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

“…Our findings from the current study reported a significant improvement in CRF following 4 weeks of school-based SIT (Table 3; Figure 2). These findings are in contrast with previous work from our group that reported a maintenance of CRF following a 7-week school-based SIT in 15-17 year-old adolescents (34). The difference in findings between the 7-week SIT study and the current 4-week SIT study may be a consequence of the higher average intensity (%HRmax) of SIT observed in this current study compared with our previous work (92% of HRmax Vs 87% of HRmax, respectively).…”

“…Our previous work found that 7 weeks of school-based running SIT implemented in the first term of school following a summer vacation period maintained CRF, insulin and glucose homeostasis compared with age matched controls receiving standard PE classes in healthy adolescents (34). We also reported that the SIT cohort subjectively self-selected greater levels of PA during this study, compared 5 with control participants and that the control group experienced a small decrease in CRF during the school term.…”

“…HIIT ranging from 2-12 weeks has been shown to be effective for improving many health outcomes in children and adolescents (5,30,33,40,48,52). Therefore, a week intervention period was chosen based on our previous study which indicated that 7 weeks was too long to fit continuously within one single Scottish school term (34). Each SIT session began with a standardised 10 min warm-up consisting of 5 min of slow jogging followed by 5 min of stretching of major muscle groups and ended with a standardised cool down comprising of dynamic and static stretches.…”

“…Despite contrasting SIT and high intensity interval training (HIIT) study designs, a consistent finding between all investigations is an improvement in CRF levels (8,10,33,34,52). A recent review demonstrated that HIIT has the potential to improve CRF by 2.2 to 23% in healthy, overweight and obese children and adolescents (5).…”

“…Yet, many children and adolescents fail to meet this minimal requirement leading some to suggest that adolescent populations may have difficulty, and perhaps little interest, in engaging in activity of this kind (9). As accumulating evidence suggests that vigorous, rather than moderate PA, may be more beneficial for a number of health outcomes in youth (37,38), many investigations have begun to explore 4 the feasibility and effectiveness of embedding sprint interval training (SIT) interventions within the school environment (8,10,33,34,52).…”