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Purpose: The aim of this study was to determine the feasibility of generalist school teachers delivering curriculum connected high-intensity interval training in a school’s physical education class time. Method: Two schools volunteered to participate. A total of 84 students (11.9 [0.5] y, M = 64 and F = 19) volunteered to participate. Four classes from 2 schools were randomized to either intervention (n = 53) or control (n = 31) for one school term (8 wk). Intervention class teachers participated in a 1-day workshop instructing them how to deliver twice weekly, high-intensity interval training sessions. The control classes continued with their usual physical education curriculum. Recruitment, intervention fidelity, and program satisfaction were assessed. Preliminary efficacy (primary outcome cardiorespiratory fitness) was quantified using generalized linear mixed models, expressed as effect size. A range of secondary outcomes was also assessed. Results: The recruitment rate was 88%. About 84% of the sessions were delivered. The heart rate peak over all sessions was 89.6% (13%) of the predicted maximum. The intervention teachers reported high levels of satisfaction. Almost all student participants were positive about participating. No adverse events occurred. The adjusted between-group difference for cardiorespiratory fitness was trivial (effect size 0.02). Conclusions: This teacher-delivered high-intensity interval training program was feasible and acceptable to both teachers and student participants. It is therefore potentially scalable.

Purpose: In a sample of healthy adolescents, the authors aimed to investigate the effects of high-intensity interval exercise (HIIE) training and detraining on baroreflex sensitivity (BRS) and it’s vascular and autonomic components at rest. Methods: Nineteen volunteers were randomly allocated to (1) 4 weeks HIIE training performed 3 times per week or (2) a control condition with no intervention for the same duration as HIIE training. PRE, POST, and following 2 weeks of detraining resting supine heart rate and blood pressure were measured, and a cross-spectral method (integrated gain [gain in low frequency]) was used to determine BRS gain. Arterial compliance (AC) was assessed as the BRS vascular component. LFgain divided by AC (LFgain/AC) was used as the autonomic determinant of BRS. Results: The HIIE training was completed with 100% compliance. HIIE did not change resting gain in low frequency (LFgain) (P = .66; effect size = 0.21), AC (P = .44; effect size = 0.36), or LFgain/AC (P = .68; effect size = 0.19) compared to control. Conclusion: Four weeks of HIIE training does not change BRS and its autonomic and vascular determinant in a sample of healthy adolescents at rest.

Background: Elevated left ventricular outflow tract (LVOT) gradients during exercise can occur in patients with hypertrophic cardiomyopathy (HCM) as well as in athletes and normal controls. The authors’ staged exercise protocol calls for imaging at rest and during each stage of exercise to evaluate the mechanism of LVOT obstruction at each stage. They investigated whether this staged approach helps differentiate HCM from athletes and normal controls. Methods: They reviewed pediatric exercise stress echocardiograms completed between January 2009 and October 2017 at their center and identified those with gene-positive HCM, athlete’s heart, and normal controls. Children with inducible obstruction (those with no LVOT gradient at rest who developed a LVOT peak gradient > 25 mm Hg during exercise) were included. LVOT peak gradient, velocity time integral, acceleration time, and deceleration time were measured at rest, submaximal stages, and peak exercise. Results: Compared with athletes, HCM patients had significantly higher LVOT peak gradients at rest (P = .019), stage 1 of exercise (P = .002), and peak exercise (P = .051), as well as a significantly higher change in LVOT peak gradient from rest to stage 1 (P = .016) and from rest to peak (P = .038). The acceleration time/deceleration time ratio of the LVOT Doppler was significantly lower in HCM patients compared with normal controls at peak exercise. Conclusions: The HCM patients who develop elevated LVOT gradients at peak exercise typically manifest early obstruction in the submaximal stages of exercise, which helps to differentiate them from athletes and normal controls.

Purpose: To assess whether adolescent athletes were affected or not in terms of mental health by the long duration at home linked to isolation enforced during the COVID-19 pandemic. Method: The study included 940 team athletes, 274 individual athletes, and 131 nonathlete controls aged 12–17 years. Demographic data were obtained with a form including questions about age, sex, sports type, and physical activity status (type, duration, and frequency) during the isolation period. Participants completed the Children’s Revised Impact of Event Scale-13, Center for Epidemiological Studies Depression Scale for Children, and State-Trait Anxiety Inventory for Children. Results: Among participants, 88% did not meet the physical activity recommendations for children and adolescents, while 42.8% felt depressed. Depressive symptoms were present in 38.1% of boys and 59.7% of girls, with girls (6.4%) having higher posttraumatic stress symptoms than boys (3.5%). Among athletes, depressive and anxiety symptoms were lower compared with nonathlete controls (P < .01). Posttraumatic stress symptoms were lower among athletes than nonathlete controls for girls (team vs control, P = .006; individual vs control, P = .002) but similar for boys (P > .05). The depression (P = .518), state (P = .866), and trait anxiety (P = .507) symptoms were similar between team athletes and individual athletes. Conclusion: Though adolescent athletes’ depression, anxiety, and posttraumatic stress symptoms were significantly lower than nonathlete controls, athletes also had high depression levels. These findings show the need to take precautions to protect the psychological health of not only nonathletes, but also athletes in the pandemic period.

Girls’ acute responses to group-based high-intensity interval exercise (HIIE) are not well characterized. Purpose: To compare acute responses to treadmill-based HIIE (TM) and body-weight resistance exercise circuit (CIRC) and to CIRC performed in a small-group setting (group CIRC). Method: Nineteen girls (9.1 [1.1] y) completed exercise testing on a TM to determine peak oxygen uptake, peak heart rate (HR_peak), and maximal aerobic speed. The TM involved eight 30-second sprints at 100% maximal aerobic speed. The CIRC consisted of 8 exercises of maximal repetitions performed for 30 seconds. Each exercise bout was followed by 30 seconds of active recovery. The blood lactate concentration was assessed preexercise and postexercise. The ratings of perceived exertion, affective valence, and enjoyment were recorded at preexercise, Intervals 3 and 6, and postexercise. Results: The mean heart rate was higher during group CIRC (92% [7%] HR_peak) than CIRC (86% [7%] HR_peak) and TM (85% [4%] HR_peak) ( ${\eta }_{\mathrm{p}}^2$  = .49). The mean oxygen uptake equaled 76% (11%) of the peak oxygen uptake for CIRC and did not differ from TM (d = 0.02). The CIRC elicited a greater postexercise blood lactate concentration versus TM (5.8 [1.7] vs 1.4 [0.4] mM, d = 3.61). The perceptual responses were similar among conditions (P > .05), and only the rating of perceived exertion increased during exercise ( ${\eta }_{\mathrm{p}}^2$  = .78). Conclusion: Whether performed individually or in a small group, CIRC represents HIIE and may be a feasible alternative to running-based HIIE.

Purpose: To assess children’s physical activity, sedentary behavior, liking, and motivation during 3 separate simulated recess conditions: playing alone, with their parent participating, and with their peer participating. Methods: Children participated in the 3 separate conditions. During each condition, the children had access to an outdoor playground and sedentary activity options for 30 minutes. Accelerometry recorded the physical activity. Time allocated to sedentary options was monitored via a stopwatch. A visual analog scale was used to assess liking, and motivation was assessed as the children’s willingness to participate in an additional 10 minutes of each condition. Results: The children sat 88% less and were 33% more physically active with their peer versus playing alone. The children also sat 65% less during the parent condition than alone. Lastly, the children reported ≥34% liking and were ≥2-fold more likely to participate in the additional 10-minute activity bout during the parent and peer conditions than alone. The differences were significant (P ≤ .05) except for the children’s decision to participate in the additional 10 minutes in the parent versus the alone condition (P = .058). Conclusions: Relative to the alone condition, the presence of a peer or parent reduced sedentary behavior and increased liking and the motivation to participate in that condition. However, only the presence of a peer increased physical activity versus alone.

This study compared the effects of self-selected exercise intensity (SEI) versus predetermined exercise intensity (PEI) on blood pressure (BP) and arterial stiffness in adolescents with obesity. A total of 37 adolescents, 14.7 (1.6) years old, body mass index ≥95th percentile were randomly allocated into SEI (n = 18; 12 boys) or PEI (n = 19; 13 boys). Both groups exercised for 35 minutes on a treadmill, 3 times per week, for 12 weeks. The SEI could set the speed at the beginning of the sessions and make changes every 5 minutes. The PEI adolescents were trained at an intensity set at 60% to 70% of heart rate reserve. Brachial and central BP, pulse pressure, augmentation index, and carotid–femoral pulse wave were determined at baseline and after 12 weeks. Both groups reduced brachial systolic BP (SEI, Δ = −9 mm Hg; PEI, Δ = −4 mm Hg; P < .01), central systolic BP (SEI, Δ = −4 mm Hg; PEI, Δ = −4 mm Hg; P = .01), and central pulse pressure (SEI, Δ = −4 mm Hg; PEI, Δ = −3 mm Hg; P = .02) without differences between groups. No changes in the augmentation index and carotid–femoral pulse wave were observed in either group. The SEI induced similar changes in various cardiovascular outcomes compared with PEI in adolescents with obesity.