Perspectives on high-intensity interval exercise for health promotion in children and adolescents

Effects of different types of exercise intensity on improving health-related physical fitness in children and adolescents: a systematic review

A substantial body of empirical evidence reveals that physical activity is associated with a wide range of positive physical and mental health outcomes. However, an absence of comprehensive syntheses is observed concerning the varying effects of different exercise intensities on the improvement of physical health among children and adolescents. The aim of this review is to systematically investigate the effects of different exercise intensities on the physical fitness of children and adolescents, to analyses the optimal exercise intensities for improving physical fitness, and to provide a relevant theoretical basis for optimizing school physical education curricula. A systematic search strategy was used in this study in four online databases (PubMed, Scopus, EBSCO and Web of Science). Intervention studies that met the inclusion criteria underwent a thorough screening process, and their methodological quality was assessed utilizing the PEDro scale. The selected literature was systematically analyzed and evaluated through induction, summary, analysis, and evaluation. These findings indicate that high-intensity exercise training exerts significant positive effects on body composition, cardiopulmonary function and muscle fitness in children and adolescents. Therefore, we suggest that schools should focus on high-intensity sports in their physical education curriculum, which can further improve the student's PHYSICAL FITNESS.

Was it a HIIT? A process evaluation of a school-based high-intensity interval training intervention

BACKGROUND

Despite a growing body of research investigating high-intensity interval training (HIIT) in schools, there are limited process evaluations investigating their implementation. This is concerning because process evaluations are important for appropriately interpreting outcome findings and augmenting intervention design. This manuscript presents a process evaluation of Making a HIIT, a school-based HIIT intervention.

METHODS

The Making a HIIT intervention spanned 8 weeks and was completed at three schools in Greater Brisbane, Australia. Ten classes (intervention group) completed 10-min teacher-led HIIT workouts at the beginning of health and physical education (HPE) lessons, and five classes (control group) continued with regular HPE lessons. The mixed methods evaluation was guided by the Framework for Effective Implementation by Durlak and DuPre.

RESULTS

Program reach: Ten schools were contacted to successfully recruit three schools, from which 79% of eligible students (n = 308, x ¯ age: 13.0 ± 0.6 years, 148 girls) provided consent. Dosage: The average number of HIIT workouts provided was 10 ± 3 and the average number attended by students was 6 ± 2. Fidelity: During HIIT workouts, the percentage of time students spent at ≥ 80% of maximum heart rate (HRmax) was 55% (interquartile range (IQR): 29%-76%). Monitoring of the control group: During lessons, the intervention and control groups spent 32% (IQR: 12%-54%) and 28% (IQR: 13%-46%) of their HPE lesson at ≥ 80% of HRmax, respectively. Responsiveness: On average, students rated their enjoyment of HIIT workouts as 3.3 ± 1.1 (neutral) on a 5-point scale. Quality: Teachers found the HIIT workouts simple to implement but provided insights into the time implications of integrating them into their lessons; elements that helped facilitate their implementation; and their use within the classroom. Differentiation: Making a HIIT involved students and teachers in the co-design of HIIT workouts. Adaption: Workouts were modified due to location and weather, the complexity of exercises, and time constraints.

CONCLUSION

The comprehensive evaluation of Making a HIIT provides important insights into the implementation of school-based HIIT, including encouragings findings for student enjoyment and fidelity and recommendations for improving dosage that should be considered when developing future interventions.

TRIAL REGISTRATION

ACTRN, ACTRN12622000534785 , Registered 5 April 2022 - Retrospectively registered.

Accumulating Sedentary Time and Physical Activity From Childhood to Adolescence and Cardiac Function in Adolescence

BACKGROUND

Increased physical activity (PA) may mitigate the negative cardiovascular health effects of sedentary behavior in adolescents. However, the relationship of PA and sedentary time from childhood with cardiac function in adolescence remains underexplored. Therefore, we investigated the associations of cumulative sedentary time and PA from childhood to adolescence with cardiac function in adolescence.

METHODS AND RESULTS

Participants were 153 adolescents (69 girls) who were aged 6 to 8 years at baseline, 8 to 10 years at 2-year follow-up, and 15 to 17 years at 8-year follow-up. Cumulative sedentary time and PA exposure between baseline and 2-year follow-up and between baseline and 8-year follow-up were measured using a combined accelerometer and heart rate monitor. Cardiac function was assessed using impedance cardiography at 8-year follow-up. The data were analyzed using linear regression analyses adjusted for age and sex. Cumulative moderate to vigorous PA (standardized regression coefficient [β]=-0.323 [95% CI, -0.527 to -0.119]) and vigorous PA (β=-0.295 [95% CI, -0.508 to -0.083]) from baseline to 8-year follow-up were inversely associated with cardiac work at 8-year follow-up. Conversely, cumulative sedentary time had a positive association (β=0.245 [95% CI, 0.092-0.398]). Cumulative vigorous PA from baseline to 8-year follow-up was inversely associated with cardiac work index at 8-year follow-up (β=-0.218 [95% CI, -0.436 to 0.000]).

CONCLUSIONS

Higher levels of sedentary time and lower levels of PA during childhood were associated with higher cardiac work in adolescence, highlighting the importance of increasing PA and reducing sedentary time from childhood.

Frontiers and hotspots of high-intensity interval exercise in children and adolescents: text mining and knowledge domain visualization

Background: During the past two decades, research on high-intensity interval exercise (HIIE) in children and adolescents has steadily accumulated, especially on the subthemes of improving cardiometabolic and cardiovascular health. However, there is still little scientific understanding of using scientometric analysis to establish knowledge maps. Exploring the relationship between known and new emerging ideas and their potential value has theoretical and practical implications in the context of a researcher's limited ability to read, analyze, and synthesize all published works. Objective: First, this study aims to provide extensive information on HIIE research in children and adolescents, including authors, institutions, countries, journals, and references. Second, the objective is to use co-occurrence, burst, and co-citation analyses based on hybrid node types to reveal hotspots and forecast frontiers for HIIE research in children and adolescents. Methods: Using the bibliographic data of the Web of Science Core Collection (WoSCC) as the data source, publications, authors, and journals were analyzed with the help of bibliometric methods and visualization tools such as CiteSpace, VOSviewer, Pajek, and Bibliometrix R package. Authorial, institutional, and national collaboration networks were plotted, along with research hotspots and research frontiers based on keyword bursts and document co-citations. Results: This study found that executive function, high-intensity interval training, heart rate variability, and insulin resistance are emerging research topics; high-intensity training, mental health, exercise intensity, and cardiometabolic risk factors are continual frontier research areas in the subthemes. Conclusion: Our study has three novel contributions. First, it explicitly and directly reflects the research history and current situation of the HIIE intervention strategy in children and adolescents. This approach makes it clear and easy to trace the origin and development of this strategy in specific groups of children and adolescents. Second, it analyzes the research hotspots of HIIE in the field and predicts the research frontiers and development trends, which will help researchers get a deeper understanding of HIIE and pediatric health research. Third, the findings will enable researchers to pinpoint the most influential scholars, institutions, journals, and references in the field, increasing the possibility of future collaborations between authors, institutions, and countries.

Morning compared to afternoon school-based exercise on cognitive function in adolescents

PURPOSE

Adolescents may be less ready to learn in the mornings due to a propensity for waking up later. High-intensity interval exercise (HIIE) has been shown to acutely improve cognitive functioning in teenagers. This within-measures study explored whether the benefit of HIIE differs when delivered in the morning or afternoon.

METHODS

37 teenagers (19 boys, 13.7 ± 0.4 years) each completed 3 trials in school; morning HIIE (MORN), afternoon HIIE (AFTER) and a no-exercise control trial (CON). The HIIE involved 10x10 second sprints, interspersed by 50 s of walking. Cognitive function was assessed using a battery of computerised tasks four times over the course of the day.

RESULTS

Z scores for reaction time, but not proportion of correct responses, were improved 45 min post exercise in the MORN trial (P < 0.01, d = 0.47), and this improvement persisted until the third (P = 0.04, d = 0.34), but not final (P = 0.93, d = 0.01), time point. Global reaction time was not improved 45 min post exercise in the AFTER trial (P = 0.17, d = 0.20). Global reaction time was quicker 45 min post morning exercise compared to the same time point in CON (P = 0.02, d = 0.56) and AFTER (P = 0.01, d = 0.72).

CONCLUSION

HIIE may be more effectual in improving cognitive functioning when delivered in the morning.

Process evaluation of school-based high-intensity interval training interventions for children and adolescents: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Several systematic reviews have been published to investigate the effectiveness of high-intensity interval training (HIIT) in schools. However, there has been limited attention given to understanding the functioning of the intervention processes, which is of paramount importance for interpreting and translating the intervention effectiveness. The aim of this systematic review is to determine the extent to which process evaluation is measured in school-based HIIT interventions and to explore the effects of process evaluation and intervention characteristics on cardiorespiratory fitness (CRF), body composition, muscular strength, and blood pressure.

METHODS

A comprehensive search was conducted in SPORT Discus (EBSCOhost), Web of Science, Scopus, Medline (Ovid) and Cochrane Central Register of Controlled Trials. The extent to which process evaluation is measured was narratively reported, alongside with the guidance of process evaluation of complex interventions by UK Medical Research Council. Meta-analyses and meta-regressions were conducted to determine the effects of process evaluation and intervention characteristics to the intervention outcomes.

RESULTS

The literature search identified 77 studies reporting on 45 school-based HIIT interventions. In total, five interventions reported process evaluation in a section or in a separate study, and only one intervention adopted a process evaluation framework. On average, 6 out of 12 process evaluation measures were reported in all interventions. Subgroup analyses did not indicate any beneficial treatment effects for studies with process evaluation group, whereas all pooled data and studies without process evaluation group showed significant improvement for CRF and body composition.

CONCLUSION

Process evaluation is frequently omitted in the literature of school-based HIIT in children and adolescents. Although reporting of process evaluation measures may not directly associate with better intervention outcomes, it allows accurate interpretation of intervention outcomes, thereby enhancing the generalisability and dissemination of the interventions.

Validation and Calibration for Embedding Rating of Perceived Exertion Into High-Intensity Interval Exercise in Adolescents: A Lab-Based Study

PURPOSE

Rating of perceived exertion (RPE) is a convenient and cost-effective tool that can be used to monitor high-intensity interval exercise (HIIE). However, no methodological study has demonstrated the validity of RPE in this context. Therefore, the aim of this study was to validate and calibrate RPE for monitoring HIIE in adolescents.

METHODS

RPE, heart rate (HR), and oxygen uptake (V˙O2) data were retrospectively extracted from 3 lab-based crossover studies, with a pooled sample size of 45 adolescents, performing either cycling-based or running-based HIIE sessions. Within-participant correlations were calculated for RPE-HR and RPE-V˙O2, and receiver operator characteristic curve analysis was used to establish RPE cut points.

RESULTS

The results showed that RPE-HR demonstrated acceptable criterion validity (r = .53-.74, P < .01), while RPE-V˙O2 had poor validity (r = .40-.48, P < .01), except for HIIE at 100% peak power (r = .59, P < .01). RPE cut points of 4 and 5 were established in corresponding to HR/V˙O2 based thresholds.

CONCLUSION

RPE has some utility in evaluating intensity during lab-based running or cycling HIIE in adolescents. Future studies should expand the validation and calibration of RPE for prescribing and monitoring HIIE in children and adolescents in field-based contexts.

Sports participation in chronic immune thrombocytopenia: Safer than you thought?

BACKGROUND/OBJECTIVES

Pediatric patients with chronic immune thrombocytopenia (ITP) commonly have activity limitations placed to prevent injury without data guiding clinical decision-making. The objective of this study was to determine risk factors associated with injury in children with chronic ITP.

DESIGN/METHODS

Retrospective single-center cohort study from January 1, 2008 to March 31, 2019 in subjects age 5-21 years with chronic ITP (platelet count < 100,000/µL for >1 year).

RESULTS

One-hundred-two subjects were included, with a mean diagnosis age of 9.3 ± 4.6 years. Mean follow-up 3.8 ± 2.3 years; 61% (62) of subjects were female; 60% (61) participated in organized sports, mean 2 ± 1 sports/subject; 8.8% (9) received ITP therapy for sports participation. Common sports: basketball (28%) and soccer (28%). There were 31 injuries in 26 subjects, and 68% (21) occurred while at play. Most common injuries: 68% (21/31) soft tissue and 23% (7/31) head trauma. Fifteen (48%) injuries were severe enough for medical evaluation at the time of injury. Only one patient received acute ITP treatment for their injury. Injury was associated with participation in high-risk sports (p < .001), male sex (p = .007), and participation in multiple organized sports (p = .008).

CONCLUSION

In this study of 102 pediatric subjects with chronic ITP, injury was mild and infrequent predominantly occurring while at play. The majority participated in organized sports safely. Risk of injury was associated with high-risk sport participation (p < .001). Only one injury necessitated ITP treatment, suggesting that participation in most sports is likely safe in children with chronic ITP.

Program Evaluation and Preliminary Efficacy of Fitness and Skill-Based High-Intensity Interval Training in Physical Education

Previous school-based high-intensity interval training (HIIT) interventions have focused on the quantity of physical activity (PA) achieved during physical education (PE) rather than students' PE experiences, including enjoyment. Purpose: To evaluate the feasibility of a fitness- and skill based HIIT intervention guided by the Self Determination Theory. Method: For this pretest-posttest randomized controlled 6-week pilot study, 4-5th grade students (15 boys, 30 girls; age = 10.5 ± 0.9 years) completed a 16-19-minute HIIT circuit (INT); whereas, 22 students (10 boys, 12 girls; age = 10.5 ± 0.9 years) engaged in regular PE (CON). Two-way mixed ANCOVA tests were performed to assess preliminary efficacy. Results: Participants reported favorable program satisfaction (mean 3.6 ± 1.5 out of 5). The physical educator reported a high feasibility survey score (31/35), and themes emerging from a program acceptability interview included positive perceptions of the HIIT program and strategies for future implementation. A large effect size was evident for cardiorespiratory fitness (ηp2 = 0.26), as VO2peak increased in INT from 53.6 ± 6.1 to 56.9 ± 7.3 ml/kg/min and decreased in CON (53.9 ± 7.0 to 52.4 ± 10.4 ml/kg/min). Students in INT exhibited greater amounts of moderate-to-vigorous PA and vigorous PA during PE versus CON, based on accelerometer data (23.4 ± 5.0 vs. 15.7 ± 4.7 min/hr, ηp2 = 0.45; 4.5 ± 2.6 vs. 2.3 ± 1.3 min/hr; ηp2 = 0.27, respectively). Conclusions: Findings support the feasibility of this fitness- and skill-based HIIT program and may be a valuable addition to elementary school PE programs.

Making a HIIT: co-design of high-intensity interval training workouts with students & teachers within the curriculum

BACKGROUND

High-intensity interval training (HIIT) interventions are becoming more common in schools. However, limited input has been sought from end-users, which can help design interventions that are more engaging and context appropriate, therefore increasing their potential for successful implementation. One method of engaging end-users is co-design, which involves an active collaboration to design solutions to pre-specified problems. This paper aimed to: (1) describe the methodology and results of the co-design process in Making a HIIT to develop HIIT workouts for a school-based intervention; and (2) evaluate the feasibility and impact of co-designing HIIT workouts with students and teachers within the health and physical education (HPE) curriculum.

METHODS

The development of the HIIT workouts occurred during obligatory HPE lessons with year seven and eight students. The co-design process included: (1) identifying barriers and facilitators to exercise to create evaluation criteria for creating the HIIT workouts; (2) exploring HIIT; (3) defining HIIT parameters (intensity and interval length); (4) creating HIIT workouts using the parameters and evaluation criteria; (5) trialling and modifying the HIIT workouts based on class feedback and intensity data. To evaluate the feasibility and impact of the co-design process, a thematic analysis was completed using teacher interviews, student discussions, and student surveys.

RESULTS

Five classes comprised of 121 students (12-14 years; 49% female) and five teachers were involved in the co-design process across three schools in Queensland, Australia. A total of 33 HIIT workouts were created aimed at satisfying the HIIT parameters and variations of the following evaluation criteria: (1) fun; (2) social; (3) achievable skill level; (4) feeling accomplished; and (5) beneficial for health. From the thematic analysis, three themes (acceptability; implementation; integration) and 12 codes contributed to the overarching understanding of the feasibility of the lessons within the curriculum and a further three themes (perceived changes to lessons; educative outcomes; personal and social capabilities) and three codes contributed towards understanding their impact.

CONCLUSION

Overall, co-designing HIIT workouts was feasible within the HPE curriculum and may have contributed to positive educative outcomes. Using this methodology could improve the implementation of HIIT interventions within HPE while supporting educative benefits.

Effects of running-based versus body-weight-based high-intensity interval training on physical fitness in healthy adolescents

Objectives: High-intensity interval training improves aerobic endurance, but the effectiveness of different training protocols is unclear. This study compared the effects of running-based high-intensity interval training (R-HIIT) and body weight-based high-intensity interval training (B-HIIT) on physical fitness in adolescents.

Methods: This was a pre-and post-test quasi-experimental design in which a seventh-grade natural class was randomly selected from three homogeneous middle schools, and then the three natural classes were randomly divided into three groups: the R-HIIT group (n = 54), the B-HIIT group (n = 55), and the control group (Con, n = 57). Both intervention groups exercised twice a week for 12 weeks with a 2:1 (1 min:30 s) load-interval ratio and exercise intensity controlled at 70%–85% maximum heart rate. R-HIIT was in the form of running, and B-HIIT was in the form of resistance exercises using the participants’ body weight. The control group was instructed to continue their normal behavior. cardiorespiratory fitness, muscle strength and endurance, and speed were measured before and after the intervention. Statistical differences between and within groups were determined using repeated measures analysis of variance.

Results: Compared to the baseline, both the R-HIIT and B-HIIT intervention groups significantly improved CRF, muscle strength, and speed (p &lt; 0.05). The B-HIIT group was significantly better than R-HIIT in improving CRF (4.48 mL/kg/min vs 3.34 mL/kg/min, p &lt; 0.05), and only the B-HIIT improved sit-up muscle endurance (ηp2 = 0.30, p &lt; 0.05).

Conclusion: The B-HIIT protocol was significantly more effective than the R-HIIT protocol in developing CRF and improving muscle health indicators.

High-intensity interval training in children and adolescents with special educational needs: a systematic review and narrative synthesis

BACKGROUND

High-intensity interval training (HIIT) has been promoted as a time-efficient exercise strategy to improve health and fitness in children and adolescents. However, there remains little consensus in the literature regarding its efficacy in children and adolescents with special educational needs (SEN). This study aimed to examine HIIT as a means of improving key health and fitness parameters in children and adolescents with SEN.

METHODS

A systematic search was conducted on eight databases (MEDLINE, Embase, SPORTDiscus, Web of Science, Scopus, PsycINFO, CINAHL, and Cochrane Library). Studies were eligible if they 1) included an HIIT protocol, 2) examined parameters related to both physical and mental aspects of health and fitness, and 3) examined children and adolescents with SEN aged 5-17 years.

RESULTS

Of the 1727 studies yielded by the database search, 13 (453 participants) were included and reviewed. We found that HIIT generally improved body composition, physical fitness, and cardiometabolic risk biomarkers across a spectrum of SEN (e.g., attention deficit hyperactivity disorder, cerebral palsy, developmental coordination disorder, and mental illness). Improvements in mental health and cognitive performance following HIIT have also been observed.

CONCLUSION

This review provides up-to-date evidence for HIIT as a viable exercise strategy for children and adolescents with SEN. Further research investigating the benefits of HIIT in a wider range of SEN populations is warranted.

TRIAL REGISTRATION

This study was registered in the International Prospective Register of Systematic Review (PROSPERO; registration number CRD42022352696).

Children's Enjoyment, Perceived Competency, and Vigorous Physical Activity During High-Intensity Interval Training in Physical Education

Purpose: Little is known about children's experience with high-intensity interval training (HIIT) during elementary school. Perceptions of enjoyment, perceived competence, and motivation are likely to drive long-term adherence and are, therefore, critical to understanding how HIIT might be implemented in this setting. The purpose of this study was to describe children's vigorous physical activity (VPA), enjoyment, and perceived competency of HIIT activities within a Self-Determination Theory framework (autonomy) in elementary school physical education (PE) classes. Methods: Participants were 402 children from a single, diverse elementary school (49.4% female, 59.6% Non-Hispanic white). Student enjoyment and perceived competency were collected following teacher- (non-autonomous) and student-led (autonomous) conditions. A sub-set of 201 children wore accelerometers to measure percent of time in VPA during HIIT conditions. This mixed factorial design was assessed through a series of repeated measures ANOVAs. Results: While children reported generally positive enjoyment and perceived competence in both conditions (rating over 4.0 on a 5-point scale), children significantly enjoyed (d = 0.44) and felt more competent (d = 0.11) during the autonomous HIIT condition compared to the nonautonomous HIIT condition. In contrast, the percent of time in VPA (d = 0.94) was significantly lower in the autonomous condition. Conclusions: These data illustrate a challenging trade-off with the design of HIIT trials. Increasing autonomy through the inclusion of student choice increased enjoyment and perceived competence of HIIT, which are likely to improve adherence, but lowered VPA, which is likely to reduce cardiometabolic impact.Abbreviations: U.S.: United States; PA: Physical activity; MVPA; Moderate-to-vigorous physical activity; PE: Physical education; CDC: Centers for Disease Control and Prevention; Randomized control trial, RCT; SDT: Self-Determination Theory; HIIT: High-intensity interval training; RCT: Randomized control trial; VPA: Vigorous physical activity; IRB; Institutional Review Board; HFZ: Healthy Fitness Zone; PACES: Physical Activity Enjoyment Scale; M: Mean; SD: Standard deviation.

Prognostic Potential of the Body Composition Indices in Predicting Positive Changes in Resting Blood Pressure after High-Intensity Interval Training in Adolescents

This study aimed to investigate the prognostic potential of body composition indices in predicting the improvement in resting blood pressure after 10 weeks of high-intensity interval training (HIIT) implemented in physical education lessons. The participants were 141 adolescents aged 16 years. Independent variables were body mass index (BMI), fat mass index (FMI), muscle mass index (SMI), and mass to fat ratio (MFR); dependent variables were systolic and diastolic blood pressure (SBP, DBP) and its indices: pulse pressure (PP), mid-blood pressure (MBP), and mean arterial pressure (MAP). The receiver operating curve (ROC) method was employed. SMI and MFR are body composition indices with prognostic potential to predict positive changes in SBP in males (SMI: AUC = 0.82; p < 0.001, MFR = 0.70; p = 0.039) and MFR in females (AUC = 0.72; p = 0.035). The respective cut-off point values used to classify participants as a beneficiary of HIIT intervention concerning SBP were SMI = 7.84 and MFR = 2.43 in males, and for SMI = 10.12 and MFR = 1.94 in females. Body composition indices based on skeletal muscle (SMI, MFR) were more likely to predict positive changes in SBP after HIIT intervention in adolescents. PP, MBP, and MAP did not reflect the detecting power of SMI and MFR. However, these thresholds' utility is limited to adolescents of 16 years of age.

Six HIT Sessions Improve Cardiorespiratory Fitness and Metabolic Flexibility in Insulin Resistant and Insulin Sensitive Adolescents with Obesity

To evaluate the effect of high-intensity interval training (HIT) on the cardiorespiratory performance and substrate oxidation pattern in insulin-resistant and insulin-sensitive obese adolescents.

METHODS

We recruited 25 obese adolescents in three schools, and trained them in six HIT sessions, comprising of six series at 100% and recovery at 50% peak velocity (Vpeak). For the evaluation, the participants were divided into two groups: insulin-resistant (IR, n = 12; HOMA index ≥3.16) and insulin-sensitive (IS, n = 13). All participants underwent cardiopulmonary and indirect calorimetry testing. We compared the effects of HIT before and after the intervention among the two groups. The data were analyzed using Student's t and Mann-Whitney (intergroup comparisons) and Student's t and Wilcoxon (pre- and post-training comparisons) tests; and Cohen's d (influence of HIT).

RESULTS

There was a significant post-training increase in Vpeak, oxygen consumption (VO2), velocity (V), and heart rate (HR) at the exertion intensity at the first ventilatory anaerobic threshold (VAT1) in both groups (p < 0.05; d < 0.02). The exercise promoted changes in substrate oxidation rates of the groups, with an increase in carbohydrate oxidation (CHOox) for both IR (p = 0.064) and IS (p = 0.034).

CONCLUSION

Six HIT sessions improved cardiorespiratory performance in both groups and increased CHOox in insulin-sensitive obese adolescents, suggesting its utility for increasing physical fitness and controlling glycemia in these population groups.

Effect of two-weeks of school-based sprint training on physical fitness, risk factors for cardiometabolic diseases and cognitive function in adolescent girls: A randomized controlled pilot trial

Background

School-based physical activity interventions are accessible to most adolescents and could enhance adolescent cardiometabolic health and cognition; yet the feasibility and success of school-based physical activity interventions is understudied.

Methods

Sixteen adolescent girls (age: 11.7 ± 0.3 y; height: 1.58 ± 0.07 m; body mass: 45.5 ± 9.2 kg) were randomized to either an intervention (2-weeks sprint training; n = 8) or control group (continuation of regular physical activity levels; n = 8). Following familiarization, all participants completed baseline measurements including fasted and postprandial capillary blood samples, a battery of cognitive function tests (Stroop Test, Sternberg Paradigm and Flanker Task), and an assessment of physical fitness (20 m sprint and multi-stage fitness test). The intervention group completed 2-weeks progressive sprint training (3 sessions per week: week one 6 × 10 s sprints, week two 8 × 10 s sprints). Follow-up measurements were completed 48 h after the final sprint training session. Data were analyzed via ANCOVA to examine between group differences at follow-up whilst controlling for baseline score.

Results

Accuracy in the intervention group during the three-item Sternberg paradigm was greater when compared with the control group (Intervention: 99.6 ± 1.1%; Control: 97.7 ± 2.2%, p = 0.046). BDNF concentration was also higher in the intervention group at follow-up than control group (Intervention: 39.12 ± 9.88 ng.ml⁻¹; Control: 22.95 ± 9.13 ng.ml⁻¹, p < 0.001). There were no differences at follow-up between the intervention and control group for measures of cardiometabolic health (fasted cytokine concentrations or postprandial glycaemic and insulinaemic responses) or on the Stroop Test or Flanker Task (all p > 0.05). However, the intervention group reported enjoying the sprint training and that they found the sessions valuable.

Conclusion

Two-weeks sprint interval training in a school-setting enhanced working memory and increased concentrations of BDNF in adolescent girls. The intervention was deemed enjoyable and worthwhile by the adolescent girls and thus the longer-term implementation of such an intervention should be examined.

Making a HIIT: study protocol for assessing the feasibility and effects of co-designing high-intensity interval training workouts with students and teachers

Background

High-intensity interval training (HIIT) is an effective strategy for improving a variety of health outcomes within the school setting. However, there is limited research on the implementation of school-based HIIT interventions and the integration of HIIT within the Health and Physical Education (HPE) curriculum. The aims of the Making a HIIT study are to: 1) describe the methodology and evaluate the feasibility of co-designing HIIT workouts with students and teachers in HPE; 2) determine the effect of co-designed HIIT workouts on cardiorespiratory and muscular fitness, and executive function; 3) understand the effect of co-design on students’ motivation, enjoyment, and self-efficacy towards the workouts; and 4) evaluate the implementation of the intervention.

Methods

Three schools will participate. Within each school, three different groups will be formed from Year 7 and 8 classes: 1) Co-Designers; 2) HIIT Only; and 3) Control. The study will include two phases. In phase one, Group 1 will co-design HIIT workouts as part of the HPE curriculum using an iterative process with the researcher, teacher, and students as collaborators. This process will be evaluated using student discussions, student surveys, and teacher interviews. In phase two, Groups 1 and 2 will use the co-designed 10-minute HIIT workouts in HPE for 8-weeks. Group 3 (control) will continue their regular HPE lessons. All students will participate in cardiorespiratory fitness, muscular fitness, and executive function assessments before and after the HIIT program or control period. Students will complete questionnaires on their motivation, enjoyment, and self-efficacy of the workouts. Differences between groups will be assessed using linear regressions to account for covariates. Heart rate and rating of perceived exertion will be collected during each HIIT session. The implementation will be evaluated using the Framework for Effective Implementation. Ethical approval was granted by the University of Queensland Human Research Ethics Committee and other relevant bodies.

Discussion

This study will be the first to co-design HIIT workouts with teachers and students within the HPE curriculum. As this study relies on co-design, each HIIT workout will differ, which will add variability between HIIT workouts but increase the ecological validity of the study.

Trial registration

ACTRN, ACTRN12622000534785, Registered 5 April 2022 – Retrospectively registered, https://www.anzctr.org.au/ACTRN12622000534785.aspx

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03440-w.

Exercise training in paediatric congenital heart disease: fit for purpose?

Exercise and physical activity (PA) have been shown to be effective, safe and feasible in both healthy children and children with congenital heart disease (CHD). However, implementing exercise training as an intervention is still not routine in children with CHD despite considerable evidence of health benefits and well-being. Understanding how children with CHD can safely participate in exercise can boost participation in PA and subsequently reduce inactivity-related diseases. Home-based exercise intervention, with the use of personal wearable activity trackers, and high-intensity interval training have been beneficial in adults' cardiac rehabilitation programmes. However, these remain underutilised in paediatric care. Therefore, the aims of this narrative review were to synthesise prescribed exercise interventions in children with CHD, identify possible limitation to exercise training prescription and provide an overview on how to best integrate exercise intervention effectively for this population into daily practice.

Physical Activity and Exercise Practice to Reduce the Sedentary Behavior in Children and Adolescents Overweight and with Obesity

Childhood obesity remains a serious public health concern all over the world [...]

School-based high-intensity interval training programs in children and adolescents: A systematic review and meta-analysis

PURPOSE

1) To investigate the effectiveness of school-based high-intensity interval training (HIIT) interventions in promoting health outcomes of children and adolescents compared with either a control group or other exercise modality; and 2) to explore the intervention characteristics and process outcomes of published school-based HIIT interventions.

METHODS

We searched Medline, Embase, CINAHL, SPORTDiscus, and Web of Science from inception until 31 March 2021. Studies were eligible if 1) participants aged 5-17 years old; 2) a HIIT intervention within a school setting ≥ 2 weeks duration; 3) a control or comparative exercise group; 4) health-related, cognitive, physical activity, nutrition, or program evaluation outcomes; and 5) original research published in English. We conducted meta-analyses between HIIT and control groups for all outcomes with ≥ 4 studies and meta-regressions for all outcomes with ≥ 10 studies. We narratively synthesised results between HIIT and comparative exercise groups.

RESULTS

Fifty-four papers met eligibility criteria, encompassing 42 unique studies (35 randomised controlled trials; 36 with a high risk of bias). Meta-analyses indicated significant improvements in waist circumference (mean difference (MD) = -2.5cm), body fat percentage (MD = -1.7%), body mass index (standardised mean difference (SMD) = -1.0), cardiorespiratory fitness (SMD = +1.0), resting heart rate (MD = -5bpm), homeostatic model assessment-insulin resistance (MD = -0.7), and low-density lipoprotein cholesterol (SMD = -0.9) for HIIT compared to the control group. Our narrative synthesis indicated mixed findings between HIIT and other comparative exercise groups.

CONCLUSION

School-based HIIT is effective for improving several health outcomes. Future research should address the paucity of information on physical activity and nutrition outcomes and focus on the integration and long-term effectiveness of HIIT interventions within school settings.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42018117567.

The high-intensity interval training introduced in physical education lessons decrease systole in high blood pressure adolescents

Increased resting blood pressure (BP) is a risk factor for many health complications. The prevalence of elevated BP is growing among adolescents. There is a need to investigate effective ways of decreasing excessive blood pressure in this age group. The study aim was to determine the effect of 10-weeks High-Intensive Interval Training (HIIT)—Tabata protocol—introduced in physical education (PE) lessons on resting blood pressure in adolescents. The sample included 52 boys aged 16.23 ± 0.33 years body height176.74 ± 6.07 (m), body weight 65.42 ± 12.51 (kg), BMI 20.89 ± 3.53 (kg/m²) and 89 girls aged 16.12 ± 0.42 years, body height 164.38 ± 6.54 (m), body weight 56.71 ± 10.23 (kg), BMI 20.93 ± 3.08 (kg/m²) from secondary school. Based on resting BP, the fractions of boys and girls with normal BP and high BP were identified and divided into experimental (EG) and control (CG) groups. EG completed a 10-weeks HIIT program (three cycles of Tabata protocol) implemented in one PE lesson during a week. The duration of the effort was 14 min. The intensity was at 75–80% of maximal heart rate. Changes in systolic and diastolic BP after the experiment were examined. The results indicated the improvement in SBP in EG with high BP compared to the rest of the groups (average reduction of 12.77 mmHg; p < 0.0001). The EG normotensive had a statistically significant higher reduction of SBP comparing CG normotensive (average decrease of 1.81 mmHG; p = 0.0089). HIIT effectively decreases BP in adolescents. Implementing HIIT in PE lessons in secondary school is recommended to improve BP parameters.

Somatic, psychological and economic benefits of regular physical activity beginning in childhood

Physical activity is a natural part of a healthy life-style, which should be nurtured from early childhood. Regular physical activity mitigates against the global problems of overweight and obesity, hypertension, anxiety and depression. It lowers the morbidity and mortality from cardiovascular disease and provides hope for sustainable economics to support an ageing population into their retirement. This is preventative health economics that can be achieved with integrated support from families, communities, health-care professionals and governments at all levels. At present, children lack the support of those responsible for them at a societal level to adequately protect them from the physical and emotional consequences of reduced physical activity.

Process Evaluation of Project FFAB (Fun Fast Activity Blasts): A Multi-Activity School-Based High-Intensity Interval Training Intervention

Introduction: Over the last decade, research into the impact of school-based high-intensity interval training (HIIT) on young people's health has markedly increased. Despite this, most authors have focused on the outcomes of their intervention, rather than the process of how the study was conducted. The aim of our study, therefore, was to conduct a mixed methods process evaluation of Project FFAB (Fun Fast Activity Blasts), a school-based HIIT intervention for adolescents. The objectives were to explore study recruitment, reach, intervention dose, fidelity, participants' experiences, context, and future implementation.

Methods: Recruitment was assessed by comparing the number of students who received study information, to those who provided consent. Reach was described as the number of participants who completed the intervention. Dose was reported via the number of HIIT sessions delivered, total exercise time commitment, HIIT exercise time, and session attendance. Post-intervention focus groups were conducted with intervention participants (n = 33; aged 14.1 ± 0.3 years; mean ± standard deviation). These discussions explored aspects of intervention fidelity (extent that the intervention was delivered as intended); participants' experiences of the HIIT sessions; context (exploration of the nuances of school-based HIIT); and ideas for future implementation.

Results: Recruitment, reach, and dose data indicate that Project FFAB was largely delivered as planned. Focus group data identified a mismatch between perceived vs. prescribed work: rest ratio for the multi-activity HIIT drills. Generally, the HIIT drills were well-received; participants often reported they were fun to complete, and the use of heart rate monitors was helpful for interpreting exercise intensity. Some participants stated that greater variety in the HIIT drills would be preferable. The timing and structure of the HIIT sessions that took place outside of physical education lessons received mixed responses.

Conclusion: Collectively, our study supports the use of school-based HIIT and provides valuable insights into how such interventions can be implemented. Project FFAB could be modified to account for individuals' preferences on when the exercise sessions took place. In addition, a wider range of activities could be included, and the prescribed work: rest ratio of the HIIT drills could be better communicated.

Acute Cardiometabolic and Perceptual Responses to Individual and Group-Based Body-Weight Resistance Exercise in Girls

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 (HRpeak), 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%] HRpeak) than CIRC (86% [7%] HRpeak) and TM (85% [4%] HRpeak) (ηp2 = .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 (ηp2 = .78).

CONCLUSION

Whether performed individually or in a small group, CIRC represents HIIE and may be a feasible alternative to running-based HIIE.

Feasibility of a school-based physical activity intervention for adolescents with disability

BACKGROUND

Adolescents with disability are less active and have lower levels of physical fitness than their typically developing peers. Schools are ideal settings to address this; however, few school-based interventions have been designed and evaluated among this group. Therefore, the aim of this pilot study was to determine the feasibility of a time-efficient school-based physical activity intervention for adolescents with disability.

METHODS

A non-randomized pilot trial was conducted with adolescents in the special education unit at one secondary school in New South Wales, Australia. Sixteen grade 11 and 12 students (aged 17.3 ± 0.7 years) participated in the 2-month physical activity intervention. Two classroom teachers were trained to facilitate the delivery of a high-intensity interval training (HIIT) program, known as Burn 2 Learn adapted (B2La). Teachers were asked to deliver 2-3 weekly HIIT sessions for a period of 2 months. Four domains of feasibility (acceptability, implementation, adaptability, and practicality) were assessed using quantitative measures at the student and teacher levels (e.g., observations, process evaluation questionnaires, and heart rate [HR] monitoring). Data were also collected from three learning and support teachers who assisted classroom teachers with intervention delivery. Preliminary efficacy of the intervention on measures of adolescents' functional capacity (6-min walk/run test) and muscular fitness (sit-to-stand test and modified push-up test) were analyzed using paired sample t-tests.

RESULTS

Moderate-to-high levels of program satisfaction were reported by both students (80% rated "Good" or "Excellent") and teachers (100% rated "Good" or "Excellent"). Teachers reported delivering 2.5 ± 0.7 sessions per week during the study. Based on researcher session observations, the program was delivered effectively by teachers (14/20). However, HR data indicated session intensity was lower than intended. The program was considered "adaptable" by teachers, with several observed modifications to HIIT sessions to cater for the needs of adolescents with disability. No adverse events were reported. We observed improvements in preliminary efficacy measures.

CONCLUSIONS

Our findings suggest it is feasible to train teachers to deliver a school-based HIIT program for adolescents with disability. Evaluation of B2La within a larger-scale effectiveness trial is warranted.

TRIAL REGISTRATION

ACTRN12621000219886 .

The acute effect of high- and moderate-intensity interval exercise on vascular function before and after a glucose challenge in adolescents

NEW FINDINGS

What is the central question of this study? What is the effect of high-intensity and moderate-intensity interval running on macro- and microvascular function in a fasted state and following a glucose challenge in adolescents? What is the main finding and its importance? Both macro- and microvascular function were improved after interval running independent of intensity. This finding shows that the intermittent exercise pattern and its associated effect on shear are important for vascular benefits. In adolescents, macrovascular function was enhanced after an acute glucose load. However, the effect of chronic glucose consumption on vascular function remains to be elucidated.

ABSTRACT

Interventions targeting vascular function in youth are an important strategy for the primary prevention of cardiovascular diseases. This study examined, in adolescents, the effect of high-intensity interval running (HIIR) and moderate-intensity interval running (MIIR) on vascular function in a fasted state and postprandially after a glucose challenge. Fifteen adolescents (13 male, 13.9 ± 0.6 years) completed the following conditions on separate days in a counterbalanced order: (1) 8 × 1 min HIIR interspersed with 75 s recovery; (2) distance-matched amount of 1 min MIIR interspersed with 75 s recovery; and (3) rest (CON). Macro- (flow-mediated dilatation, FMD) and microvascular (peak reactive hyperaemia, PRH) function were assessed immediately before and 90 min after exercise/rest. Participants underwent an oral glucose tolerance test (OGTT) 2 h after exercise/rest before another assessment of vascular function 90 min after the OGTT. Following exercise, both HIIR and MIIR increased FMD (P = 0.02 and P = 0.03, respectively) and PRH (P = 0.04, and P = 0.01, respectively) with no change in CON (FMD: P = 0.51; PRH: P = 0.16) and no significant differences between exercise conditions. Following the OGTT, FMD increased in CON (P < 0.01) with no changes in HIIR and MIIR (both P > 0.59). There was no change in PRH after the OGTT (all P > 0.40). In conclusion, vascular function is improved after interval running independent of intensity in adolescents. Acute hyperglycaemia increased FMD, but prior exercise did not change vascular function after the OGTT in youth.

Process Evaluation of a School-Based High-Intensity Interval Training Program for Older Adolescents: The Burn 2 Learn Cluster Randomised Controlled Trial

Process evaluations can help to optimise the implementation of school-based physical activity interventions. The purpose of this paper is to describe the process evaluation of a school-based high-intensity interval training (HIIT) program for older adolescent students, known as Burn 2 Learn (B2L). B2L was evaluated via a cluster randomised controlled trial in 20 secondary schools (10 intervention, 10 control) in New South Wales, Australia. Teachers (n = 22 (55% female)) from the 10 intervention schools, delivered the program over three phases (Phases 1 and 2, 6 months; Phase 3, 6 months) to older adolescent students (n = 337 (50% female); mean ± standard deviation (SD) age = 16.0 ± 0.4 years). Process evaluation data were collected across the 12-month study period. Teachers delivered 2.0 ± 0.8 and 1.7 ± 0.6 sessions/week in Phases 1 and 2 respectively (mean total 25.9 ± 5.2), but only 0.6 ± 0.7 sessions/week in Phase 3. Observational data showed that session quality was high, however heart rate (HR) data indicated that only half of the students reached the prescribed threshold of ≥85% predicted HRmax during sessions. Over 80% of teachers reported they intended to deliver the B2L program to future student cohorts. Almost 70% of students indicated they intended to participate in HIIT in the future. Teachers considered the program to be adaptable, and both students and teachers were satisfied with the intervention. B2L was implemented with moderate-to-high fidelity in Phases 1 and 2, but low in Phase 3. Our findings add to the relatively scant process evaluation literature focused on the delivery of school-based physical activity programs.

Cardiometabolic and Perceptual Responses to Body-Weight Resistance High-Intensity Interval Exercise in Boys

The majority of studies examining children's responses to high-intensity interval exercise primarily utilized running; however, this modality does not require/include other important aspects of physical activity including muscular fitness.

PURPOSE

To compare acute responses between a body weight resistance exercise circuit (CIRC) and treadmill-based (TM) high-intensity interval exercise.

METHOD

A total of 17 boys (age = 9.7 [1.3] y) completed a graded exercise test to determine peak heart rate, peak oxygen uptake (VO2peak), and maximal aerobic speed. Sessions were randomized and counterbalanced. CIRC required 2 sets of 30-second maximal repetitions of 4 exercises. TM included eight 30-second bouts of running at 100% maximal aerobic speed. Both included 30-second active recovery between bouts. Blood lactate concentration was measured preexercise and postexercise. Rating of perceived exertion, affective valence, and enjoyment were recorded preexercise, after intervals 3 and 6, and postexercise.

RESULTS

Participants attained 88% (5%) peak heart rate and 74% (9%) VO2peak for CIRC and 89% (4%) peak heart rate and 81% (6%) VO2peak for TM, with a significant difference in percentage of VO2peak (P = .003) between protocols. Postexercise blood lactate concentration was higher following CIRC (5.0 [0.7] mM) versus TM (2.0 [0.3] mM) (P < .001). Rating of perceived exertion, affective valence, and enjoyment responses did not differ between protocols (P > .05).

CONCLUSION

HR responses were near maximal during CIRC, supporting that this body-weight circuit is representative of high-intensity interval exercise.

Associations between gender, school socioeconomic status, and cardiorespiratory fitness among elementary and middle school students

Background

Schools play an important role in providing access to physical activity opportunities for children. There are common economic and gender disparities in physical activity and health-related fitness among children, which may inform a school’s programming needs. The purpose of this study is to gain a better understanding about gender, school-level socioeconomic status, and children’s cardiorespiratory fitness.

Methods

This observational study used 2017–2018 school year data from schools in the Dallas Metropolitan area participating in the Healthy Zone School (HZS) program. Three data sources were integrated: 1) FitnessGram® data, 2) school-level data from the Texas Education Agency, and 3) HZS survey data. Being in the Healthy Fitness Zone (HFZ) for aerobic capacity was the dependent variable, and gender and the percentage of economically disadvantaged students (at the school-level) were key independent variables. Mixed-effects logistic regression models examined associations between dependent and independent variables. Final models were adjusted for age and type of aerobic test.

Results

There were 67 schools and 15,052 students included in the analysis. When testing main effects, girls had lower odds for being in the HFZ for aerobic capacity than boys (OR = 0.54, CI = 0.47–0.62). Additionally, having a greater percentage of students who were economically disadvantaged was associated with lower odds for being in the HFZ for aerobic capacity (0.98, CI = 0.98–0.99). There was a significant interaction between gender and the percentage of economically disadvantaged students. Results indicated girls had even lower odds (than boys) for being in the HFZ in schools with 90% economically disadvantaged students (OR = 0.44, CI = 0.35–0.55) versus in schools with 15% economically disadvantage students (OR = 0.62, CI = 0.51–0.76).

Conclusions

Results suggest girls in Healthy Zone Schools have lower odds to meet aerobic capacity fitness standards than boys. Additionally, boys and girls in schools serving a greater percentage of economically disadvantaged students have lower odds to meet aerobic capacity fitness standards. Last, girls have even lower odds of meeting HFZ standard when attending a school serving a greater percentage of economically disadvantaged students. Thus, schools need to provide more programs for girls targeting aerobic physical activity. This is especially important for schools serving a high percentage of low-income students.

Identifying facilitators and barriers for adolescents participating in a school-based HIIT intervention: the eXercise for asthma with commando Joe's® (X4ACJ) programme

BACKGROUND

High-intensity interval training (HIIT) elicits numerous health benefits, but little evidence is available regarding the feasibility of delivering school-based HIIT interventions. The aim of this study was to explore adolescents' perceptions of a 6-month, 3 × 30-min sessions per week, HIIT intervention delivered either before or after school.

METHOD

Eighty adolescents allocated to the intervention group (13.3 ± 1.0 years; 45 boys) were invited to take part in semi-structured focus groups post-intervention. Participants were categorised as attendees (≥40% attendance) or non-attendees (< 5% attendance). Data were transcribed verbatim and thematically analysed deductively, with key emergent themes represented using pen profiles.

RESULTS

Results showed that a school-based HIIT intervention can be an enjoyable form of exercise. Irrespective of attendance, similar facilitators and barriers to participating were highlighted, including benefits of participation, content of the exercise session and the intervention instructor.

CONCLUSION

This study provides support for the delivery of a HIIT intervention in a school setting but highlights the importance of a flexible design and delivery to accommodate competing interests. There is a need to educate adolescents on the possible benefits of participation and to make the sessions enjoyable in order to increase their extrinsic and intrinsic motivation to sustain participation.

Acute Cardiometabolic Responses to Multi-Modal Integrative Neuromuscular Training in Children

Integrative neuromuscular training (INT) has emerged as an effective strategy for improving health- and skill-related components of physical fitness, yet few studies have explored the cardiometabolic demands of this type of training in children. The aim of this study was to examine the acute cardiometabolic responses to a multi-modal INT protocol and to compare these responses to a bout of moderate-intensity treadmill (TM) walking in children. Participants (n = 14, age 10.7 ± 1.1 years) were tested for peak oxygen uptake (VO₂) and peak heart rate (HR) on a maximal TM test and subsequently participated in two experimental conditions on nonconsecutive days: a 12-min INT protocol of six different exercises performed twice for 30 s with a 30 s rest interval between sets and exercises and a 12-min TM protocol of walking at 50% VO₂peak. Throughout the INT protocol mean VO₂ and HR increased significantly from 14.9 ± 3.6 mL∙kg^-1∙min^-1 (28.2% VO₂ peak) to 34.0 ± 6.4 mL∙kg^-1∙min^-1 (64.3% VO₂ peak) and from 121.1 ± 9.0 bpm (61.0% HR peak) to 183.5 ± 7.9 bpm (92.4% HR peak), respectively. While mean VO₂ for the entire protocol did not differ between INT and TM, mean VO₂ and HR during selected INT exercises and mean HR for the entire INT protocol were significantly higher than TM (all Ps ≤ 0.05). These findings suggest that INT can pose a moderate to vigorous cardiometabolic stimulus in children and selected INT exercises can be equal to or more metabolically challenging than TM walking.

School-based physical activity intervention for older adolescents: rationale and study protocol for the Burn 2 Learn cluster randomised controlled trial

INTRODUCTION

This trial aims to investigate the impact of a school-based physical activity programme, involving high-intensity interval training (HIIT), on the physical, mental and cognitive health of senior school students.

METHODS AND ANALYSIS

The Burn 2 Learn (B2L) intervention will be evaluated using a two-arm parallel group cluster randomised controlled trial with allocation occurring at the school level (to treatment or wait-list control). Schools will be recruited in two cohorts from New South Wales, Australia. The trial will aim to recruit ~720 senior school students (aged 16-18 years) from 20 secondary schools (ie, 10 schools per cohort). A range of implementation strategies will be provided to teachers (eg, training, equipment and support) to facilitate the delivery of HIIT sessions during scheduled classes. In phase I and II (3 months each), teachers will facilitate the delivery of at least two HIIT sessions/week during lesson-time. In phase III (6 months), students will be encouraged to complete sessions outside of lesson-time (teachers may continue to facilitate the delivery of B2L sessions during lesson-time). Study outcomes will be assessed at baseline, 6 months (primary end point) and 12 months. Cardiorespiratory fitness (shuttle run test) is the primary outcome. Secondary outcomes include: vigorous physical activity, muscular fitness, cognition and mental health. A subsample of students will (i) provide hair samples to determine their accumulated exposure to stressful events and (ii) undergo multimodal MRI to examine brain structure and function. A process evaluation will be conducted (ie, recruitment, retention, attendance and programme satisfaction).

ETHICS AND DISSEMINATION

This study has received approval from the University of Newcastle (H-2016-0424) and the NSW Department of Education (SERAP: 2017116) human research ethics committees.

TRIAL REGISTRATION NUMBER

ACTRN12618000293268; Pre-results.

Perceptual and Cardiorespiratory Responses to High-Intensity Interval Exercise in Adolescents: Does Work Intensity Matter?

High-intensity interval exercise (HIIE) may not elicit prominent unpleasant feelings even with elevated perceived exertion and physiological stress in adolescents. However, the influence of different HIIE work intensities on the affective experience and cardiorespiratory responses is unknown. This study examined the acute affective, enjoyment, perceived exertion and cardiorespiratory responses to HIIE with different work intensities in adolescents. Participants (n = 16; 8 boys; age 12.0 ± 0.3 years) performed, on separate days, HIIE conditions consisting of 8 x 1-minute work-intervals at 70%, 85%, or 100% peak power separated by 75 seconds recovery at 20 W. Affect, enjoyment and rating of perceived exertion (RPE) were recorded before, during, and after HIIE. Heart rate (HR) and oxygen uptake were collected during HIIE. Affect declined in all conditions (p < 0.01) but 100%HIIE elicited significantly lower affect than 70%HIIE and 85%HIIE at work-interval 8 (all p < 0.02, ES > 1.74; 70%HIIE = 2.5 ± 0.8; 85%HIIE = 1.1 ± 1.5; 100%HIIE = -1.5 ± 1.4 on feeling scale). Similar enjoyment was evident during and after all conditions (all p > 0.44). RPE was significantly higher during 100%HIIE than 70%HIIE and 85%HIIE across all work-intervals (all p < 0.01, ES > 1.56). The majority of the participants attained ≥90%HR_max during 85%HIIE (87%) and 100%HIIE (100%), but not during 70%HIIE (6%). Affect responses during HIIE are dependent on the intensity of the work-interval and are not entirely negative (unpleasant feelings). Despite similar enjoyment, positive affect experienced during 70%HIIE and 85%HIIE could serve as a strategy to encourage exercise adoption and adherence in adolescents, but only 85%HIIE elicits sufficient HR stimulus to facilitate potential health benefits.

How I approach managing student athletes at risk for bleeding

Frequently, pediatric hematologists need to provide guidance regarding sports participation for children with congenital coagulopathies, immune thrombocytopenia, and those receiving anticoagulation. Although sports participation has clear health and psychosocial benefits, it can be associated with harm secondary to bleeding from injury. Decision-making for sports involvement should be individualized, patient centered, and well informed. This review focuses on the current data regarding the benefit as well as risks for sports participation and provides a framework for advising and supporting the student athlete who is at risk for bleeding.

Feasibility and Preliminary Efficacy of a Teacher-Facilitated High-Intensity Interval Training Intervention for Older Adolescents

PURPOSE

This study was designed to assess the feasibility and preliminary efficacy of a teacher-facilitated high-intensity interval training intervention for older adolescents (ie, 16-18 y).

METHODS

Two secondary schools from New South Wales, Australia were recruited, and participants (ie, grade 11 students; 16.2 [0.4] y) were randomized at the school level to the Burn 2 Learn intervention (n = 38), or a wait-list control group (n = 30). Teachers were trained to facilitate the delivery of the novel high-intensity interval training program, which involved 3 sessions per week (∼12-20 min) for 14 weeks. A range of process measures were used to assess intervention feasibility (ie, recruitment, retention, attendance, and program satisfaction). Primary (cardiorespiratory fitness, determined using the progressive aerobic cardiovascular endurance run shuttle run test) and secondary outcomes were assessed at baseline and posttest (14-wk).

RESULTS

Sixty-eight grade 11 students were recruited at baseline (85% of target sample), 61 participants completed posttest assessments (90% retention) and on average, participants performed 1.9 sessions per week. Overall, teachers (4.0/5) and students (4.0/5) were satisfied with the Burn 2 Learn program. Group by time effects were observed for cardiorespiratory fitness (8.9 laps; 95% confidence intervals, 1.7-16.2) and a selection of secondary outcomes.

CONCLUSION

This study provides evidence for the feasibility and preliminary efficacy of a teacher-facilitated high-intensity interval training intervention for older adolescents.

High-Intensity Interval Training Performed by Young Athletes: A Systematic Review and Meta-Analysis

Background: High-intensity interval training (HIIT) is as a time-efficient alternative to moderate- or low-intensity continuous exercise for improving variables related to endurance and anaerobic performance in young and adolescent athletes.

Objectives: To assess original research about enhancement of endurance and anaerobic exercise performance in young and adolescent athletes performing HIIT.

Method: Relevant articles published in peer-reviewed journals were retrieved from the electronic databases PubMed and SPORTDiscus in December 2017. Inclusion criteria were: (i) controlled trials (HIIT vs. alternative training protocol) with pre-post design; (ii) healthy young athletes (≤18 years); (iii) assessing variables related to endurance and exercise performance. Hedges' g effect size (ES), and associated 95% confidence intervals were calculated for comparison of any outcome between experimental (HIIT) and alternative training protocol.

Results: Twenty four studies, involving 577 athletes (mean age: 15.5 ± 2.2 years), were included in this review. HIIT exerted no or small positive mean ES on peak oxygen uptake (VO_2peak), running performance, repeated sprint ability, jumping performance and submaximal heart rate. Although the mean ES for changes in VO_2peak with HIIT is small (mean g = 0.10±0.28), the average increase in VO_2peak from pre to post HIIT-interventions were 7.2 ± 6.9% vs. 4.3 ± 6.9% with any other alternative intervention. HIIT largely and positively affected running speed and oxygen consumption at various lactate- or ventilatory-based thresholds, as well as for sprint running performance. Calculations showed negative mean ES for change-of-direction ability (large), and peak blood lactate concentrations (small). Mean duration per training session for HIIT was shorter than for control interventions (28 ± 15 min vs. 38 ± 24 min).

Conclusion: The present findings suggest that young athletes performing HIIT may improve certain important variables related to aerobic, as well as anaerobic, performance. With HIIT, most variables related to endurance improved to a higher extent, compared to alternative training protocols. However, based on ES, HIIT did not show clear superiority to the alternative training protocols. Nevertheless, young athletes may benefit from HIIT as it requires less time per training session leaving more time for training sport specific skills.

Acute Cardiometabolic Responses to Medicine Ball Interval Training in Children

Medicine ball interval training (MBIT) has been found to be an effective exercise modality in fitness programs, yet the acute physiological responses to this type of this exercise in youth are unknown. The purpose of this study was to examine the acute cardiometabolic responses to MBIT in children. Fourteen children (mean age 10.1 ± 1.3 yr) were tested for peak oxygen uptake (VO₂peak) on a treadmill and subsequently (> 48 hours later) performed a progressive 10 min MBIT protocol of 5 exercises (EX): standing marches (EX1), alternating lunges (EX2), squat swings (EX3), chest passes (EX4) and double arm slams (EX5). A 2.3 kg medicine ball was used for all trials and each exercise was performed twice for 30 sec with a 30 sec rest interval between sets and exercises. Participants exercised while connected to a metabolic system and heart rate (HR) monitor. During the MBIT protocol, mean HR significantly (p<0.05, η² = 0.89) increased from 121.5 ± 12.3 bpm during EX1 to 178.3 ± 9.4 bpm during EX5 and mean VO₂ significantly (p<0.05, η²= 0.88) increased from 15.5 ± 2.9 ml × kg^-1 × min^-1 during EX1 to 34.9 ± 5.1 ml × kg^-1 × min^-1during EX5. Mean HR and VO₂ values during MBIT ranged from 61.1% to 89.6% of HRpeak and from 28.2% to 63.5% of VO₂peak. These descriptive data indicate that MBIT can pose a moderate to vigorous cardiometabolic stimulus in children.

Acute Cardiometabolic Responses to a Novel Training Rope Protocol in Children

Faigenbaum, AD, Kang, J, Ratamess, NA, Farrell, A, Golda, S, Stranieri, A, Coe, J, and Bush, JA. Acute cardiometabolic responses to a novel training rope protocol in children. J Strength Cond Res 32(5): 1197-1206, 2018-The purpose of this study was to quantify the acute cardiometabolic responses to a novel training rope (TR) protocol in children. Fifteen boys (10.6 ± 1.4 years) were tested for peak oxygen uptake (V[Combining Dot Above]O2) on a treadmill and subsequently (2-7 days later) performed a progressive 10-minute protocol of 5 TR exercises (EX): EX1: standing side-to-side waves, EX2: seated alternating waves, EX3: standing alternating waves, EX4: jumping jacks, and EX5: double-arm slams. Participants performed 2 sets of each TR exercise for 30 seconds per set with a 30-second rest interval between sets and exercises. A 12.8-m TR (4.1 kg) was used for all trials, and a metronome was used to standardize cadence. Peak values for V[Combining Dot Above]O2 and HR during the treadmill test were 47.4 ± 8.8 ml·kg·min and 195.1 ± 6.6 b·min, respectively. During the TR protocol, mean V[Combining Dot Above]O2 and HR significantly increased (p ≤ 0.05) from set 1 of EX1 (10.3 ± 2.6 ml·kg·min and 103.2 ± 11.6 b·min, respectively) to set 2 of EX5 (30.0 ± 3.9 ml·kg·min and 168.6 ± 11.8 b·min, respectively). Percentage of peak V[Combining Dot Above]O2 and peak HR values attained during the TR protocol ranged from 21.5 to 64.8% and from 52.9 to 86.4%, respectively. These descriptive data indicate that TR exercise can pose a moderate to vigorous cardiometabolic stimulus in children and with proper supervision and instruction may serve as a worthwhile complement to youth fitness programs.