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

Enhancing Adolescent Physical Fitness and Well-Being: A School-Based High-Intensity Interval Training Program

Background: The aim of this study is to investigate the effects of a school-based high-intensity interval training (HIIT) program on quality of life and physical fitness in adolescents. Methods: The study included 60 male adolescents (16.2 ± 0.6 years), randomly assigned to one of two groups: the HIIT group (n = 30) and the control group (CG, n = 30). Participants completed the KIDSCREEN-27 questionnaire to evaluate quality of life and physical fitness tests, including vertical jump, repetitive strength, agility, and flexibility. The experimental program consisted of a 12-week intervention integrated into the warm-up phase of regular physical education (PE) classes. Each PE class lasted 45 min, with the HIIT regimen occupying 10 min of the warm-up phase. The HIIT sessions followed a Tabata-style structure, performed twice weekly. A two-way ANOVA with repeated measures assessed group and time interaction effects. Results: The results revealed changes in physical well-being following the HIIT intervention (p = 0.01) compared to the control group (p = 0.42). The results of the two-way ANOVA with repeated measures revealed interaction effects between group and time for the various fitness tests, countermovement jump (p = 0.04), 4 × 10 m agility test (p = 0.02), medicine ball throw test (p = 0.04), and sit-ups (30 s) (p = 0.01). Conclusions: This study highlights the effectiveness of school-based HIIT in significantly enhancing physical well-being and physical fitness among adolescents.

Comparative effectiveness of school-based obesity prevention programs for children and adolescents: a systematic review and network meta-analysis

Introduction

While many randomized controlled trials (RCTs) have demonstrated the positive effects of school-based programs in reducing body fat among children and teenagers, there is no conclusive evidence to indicate that one approach is superior to another, largely due to the lack of direct and indirect comparisons. This study evaluated the relative effectiveness of various school-based obesity prevention initiatives in improving body mass index (BMI) among children and adolescents using network meta-analysis.

Methods

Searches included four databases focusing on articles published in English between the years 2002 and 2024. The primary outcomes were the BMI and BMI z-scores (BMIz) (kg/m2). The mean differences (MDs) for each outcome were calculated before and after treatment. The current systematic review synthesized 53 RCTs with a sample of 68,489 children and adolescents.

Results

The results illustrated that the physical activity (PA) only arm was the most effective intervention in improving BMI (MD: -0.42, 95% credible interval (Crl) -0.79, -0.07; p = 0.02), while the multiple-component intervention was the most effective in improving BMIz (MD: -0.08, 95% Crl: -0.16, -0.01; p = 0.03). Inversely, PA and another component arm were the least effective interventions in improving BMI (MD: 0.64, 95% Crl: -0.23, 1.53; p = 0.15). In addition, diet and nutrition only arm was the least effective intervention in improving BMIz (MD: 0.09, 95% Crl: -0.11, 0.28; p = 0.36).

Discussion

In conclusion, both PA-only and multiple-component arms are effective intervention tools/strategies for reducing BMI-related outcomes. However, further large-scale, well-designed studies are needed to investigate the elements of multiple-component arms.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/ identifier CRD42021234742.

High-intensity interval training for improving cardiometabolic health in children and adolescents: An umbrella review of systematic reviews

High-intensity interval training (HIIT) is an emerging exercise strategy to improve health and fitness, but previous studies have evaluated HIIT interventions across different populations and outcomes. This review aimed to comprehensively synthesize published evidence on the effects of HIIT on key cardiometabolic health parameters in children and adolescents. We searched seven databases until February 2024. Systematic reviews were eligible if they 1) compared HIIT and active/non-active control conditions with meta-analysis, 2) examined cardiorespiratory fitness, body composition and cardiometabolic risk biomarkers, and 3) examined children and adolescents. We included 18 systematic reviews with meta-analysis, including 223 original studies and 13,900 unique participants. HIIT is effective for cardiorespiratory fitness in children and adolescents with diverse health and weight status (median standardized mean difference [SMD] = 0.75). Improvements in body composition and several cardiometabolic risk biomarkers, including systolic blood pressure (median SMD = -0.40), diastolic blood pressure (median SMD = -0.22), triglyceride (median SMD = -0.30), low-density lipoprotein cholesterol (median SMD = -0.90), and high-density lipoprotein cholesterol (median SMD = 0.34), have also been observed following HIIT, with a notably more pronounced effect in youth with overweight/obesity or metabolic disorders. Our umbrella review supports the effectiveness of HIIT in enhancing cardiometabolic health, suggesting its integration into physical activity promotion programmes in schools and communities.

Effectiveness of a school-based high-intensity interval training intervention in adolescents: study protocol of the PRO-HIIT cluster randomised controlled trial

Introduction

High-intensity interval training (HIIT) is an effective strategy for improving a variety of health and fitness outcomes within school settings. Incorporating HIIT into existing physical activity opportunities appears practically feasible, yet the process evaluation and effectiveness of this strategy needs to be further evaluated. Therefore, a PRO-HIIT intervention will be conducted to evaluate the effectiveness of a 12-week school-based HIIT intervention on cardiorespiratory fitness, physical activity, body composition, muscular strength, bone health, cognitive function, wellbeing and academic performance among 12-13-year-olds.

Methods and analysis

Eight classes of year 7 students (12-13-year-olds) from a secondary school in Ningbo, China, will be recruited and randomly allocated into an intervention or control group. While the control group maintains their usual activities, a 6 to 10 min HIIT session will be embedded in the physical education or physical activity lessons five days a week for 12 weeks for the intervention group. Training workshops will be conducted for participants, teachers, and research staff for facilitating the intervention. Outcome data will be collected at three time points: pre- and post-intervention, and two months (summer holiday) upon completion of the intervention. Linear mixed models will be used to analyse the impact of groups (intervention and control), timepoints (pre-, post- and two-month after intervention) and group by time interactions. The implementation process of the intervention will be evaluated using a process evaluation framework.

Ethics and dissemination

Ethics approval is obtained from the Ningbo University Ethics Committee (TY2024002). Results from PRO-HIIT study will be disseminated via peer-reviewed journals, scientific conferences as well as local education system. The study protocol has been retrospectively registered on ClinicalTrials.gov Protocol Registration and Results System (NCT06374732), https://clinicaltrials.gov/study/NCT06374732.

Effects of High-Intensity Interval Training on the Parameters Related to Physical Fitness and Health of Older Adults: A Systematic Review and Meta-Analysis

BACKGROUND

As a novel and time-efficient exercise form, high-intensity interval training (HIIT) has shown great potential in improving health-related physical fitness among diverse populations. However, empirical evidence on its efficacy among the elderly has not been well summarized. This systematic review and meta-analysis aimed to determine the effect of HIIT interventions on the parameters related to physical fitness and health of older adults, including resting heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), cardiorespiratory fitness (CRF), body mass index (BMI), body fat percent (BF%), waist circumference (WC), muscular endurance (ME), muscular strength (MS), muscular power (MP), balance and flexibility, compared to non-exercise and other-exercise (e.g., moderate-intensity continuous training, resistance training) conditions.

METHODS

Literature published from January 2000 to May 2023 was collected through extensive searches across eight databases and relevant review papers. Randomized controlled trials (RCTs) featuring a minimum 2-week exercise intervention for older adults (≥ 60 years) were included. The pooled effect size of Hedges'g was estimated using random-effects models in R. Meta-regression was performed for both categorical (health status, duration of training programme, and frequency) and continuous moderators (mean age, male rate, and attrition rate).

RESULTS

Forty-four eligible RCTs with 1863 participants (52.1% female; 60.5-81.2 years) were included in the quantitative analysis. Compared to non-exercise condition, HIIT significantly improved resting HR (g = -0.36, 95%CI = [-0.67, -0.05], P = 0.032), SBP (g = -0.29, 95%CI = [-0.54, -0.03], P = 0.008), CRF (g = 0.77, 95%CI = [0.51, 1.04], P < 0.001), BF% (g = -0.26, 95%CI = [-0.41, -0.11], P = 0.006), MS (g = 0.47, 95%CI = [0.23, 0.71], P = 0.004), ME (g = 0.65, 95%CI = [0.10, 1.19], P = 0.036), and balance (e.g., timed-up-and-go) (g = -0.79, 95%CI = [-1.19, -0.40], P = 0.035). Compared to other-exercise condition, HIIT significantly improved resting HR (g = -0.11, 95%CI = [-0.21, -0.01], P = 0.029), SBP (g = -0.14, 95%CI = [-0.28, -0.01], P = 0.038), and CRF (g = 0.23, 95%CI = [0.07, 0.38], P = 0.008). No significant difference was found between HIIT and non-exercise condition for DBP, BMI and WC, as well as between HIIT and other-exercise condition for DBP, BMI, BF%, WC, ME, and balance (all P > 0.05). Meta-regression indicated that mean age moderated the HIIT effect on resting HR (b = -0.02, P = 0.014; HIIT vs. other-exercise condition) and SBP (b = 0.03, P = 0.048; HIIT vs. non-exercise), and attrition rate moderated the effect on CRF (b = 0.03, P = 0.007; HIIT vs. non-exercise).

CONCLUSION

This study supports the efficacy of HIIT in improving resting HR, SBP, CRF, BF%, MS, ME and balance among older adults. More empirical evidence is needed to determine the efficacy of HIIT for MP and flexibility in this population.

TRIAL REGISTRATION

PROSPERO CRD42022316246.

Effect of eight-week high-intensity interval training versus moderate-intensity continuous training programme on body composition, cardiometabolic risk factors in sedentary adolescents

Objectives

This study aimed to assess and compare the effect of an 8-week high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) programme on body composition and cardiovascular metabolic outcomes of sedentary adolescents in China.

Methods

Eighteen sedentary normal-weight adolescents (age: 18.5 ± 0.3 years, 11 females) were randomized into three groups. HIIT group protocol consisted of three sessions/week for 8-week of "all out" sprints to reach 85%-95% of HRmax, and MICT group protocol undertook three sessions/week for 8-week of continuous running to reach 65%-75% of HRmax. The control group resumed normal daily activities without any intervention. Blood pressure and body composition were measured, and fasting blood samples were obtained at baseline and 48 h post-trial. Mixed-design ANOVA analysis was employed followed by post hoc t-tests and Bonferroni alpha-correction was used to evaluate interaction, between-group, and within-group differences, respectively.

Results

Results indicated that HIIT and MICT similarly affected body fat mass (p = 0.021, ES = 0.19; p = 0.016, ES = 0.30, respectively), body fat percentage (p = 0.037, ES = 0.17; p = 0.041, ES = 0.28, respectively), visceral fat area (p = 0.001, ES = 0.35; p = 0.003, ES = 0.49, respectively) of body composition. A positive outcome was observed for waist/hip ratio (p = 0.033, ES = 0.43) in HIIT, but not MICT (p = 0.163, ES = 0.33). No significant differences were found between groups for any clinical biomarkers. However, pairwise comparison within the group showed a significant decrease in systolic blood pressure (p = 0.018, ES = 0.84), diastolic blood pressure (p = 0.008, ES = 1.76), and triglyceride (p = 0.004, ES = 1.33) in HIIT, but no significant differences were found in the MICT and Control group.

Conclusion

Both 8-week HIIT and MICT programmes have similar positive effects on reducing body fat mass, fat percentage, and visceral fat area. However, sedentary adolescents may have limited scope to decrease insulin resistance after these 8-week interventions. Notably, the 8-week HIIT intervention was highly effective in increasing cardiometabolic health compared to the MICT. The exercise intensity threshold value and metabolic outcomes of high-intensity interval sprints should be explored further to extend the long-term benefit in this cohort.

Effectiveness of high intensity and sprint interval training on metabolic biomarkers, body composition, and physical fitness in adolescents: randomized controlled trial

Objective

The aim of this study was to evaluate the effect of HIIT and SIT programmes on body composition, blood pressure, lipid profile, glucose, cardiorespiratory fitness, and strength of adolescents and to compare the effect between those different protocols.

Methods

Sixty adolescents were recruited from a high school and were randomly placed into three groups. SIT and HIIT undertook a training for 8 weeks, twice a week, for 12 min per session, during their Physical Education lessons. SIT group performed 6 sets of 60 s of work (90-95%HRmax) / 60 s of rest (50-55%HRmax), and HIIT group performed 3 sets of 2 min of work (80-85%HRmax) / 2 min of rest (50-55%HRmax).

Results

After adjustment by sex, both experimental groups exhibited a significant reduction in fat mass (p < 0.01), and trunk fat mass (p < 0.01), as well as a significant increase in lean mass (p = 0.01; <0.01), hand-grip strength (p < 0.01) and standing long jump (p = 0.05-0.04, respectively). In addition, HIIT showed a significant (p < 0.05) improvement in blood pressure, diastolic blood pressure, heart rate and VO2max, and a tendency toward a significant reduction in low density lipoprotein.

Conclusion

The implementation of a HIIT protocol within high school Physical Education sessions, maintained for 8 weeks, at a rate of 3 sets of 2 min of work (80-85% RHR)/2 min of rest (50-55% RHR) generated adaptations such as improved fitness condition, changes in body composition, and improvements in blood parameters and blood pressure. However, the group of adolescents who performed SIT, shorter but more intense sets, did not experience as many benefits.

Effects of School-Based High-Intensity Interval Training on Hemodynamic Parameters and Heart Rate Variability: A Randomized Controlled Trial

ABSTRACT

Ketelhut, S, Ketelhut, K, Ketelhut, SR, and Ketelhut, RG. Effects of school-based high-intensity interval training on hemodynamic parameters and heart rate variability: A randomized controlled trial. J Strength Cond Res 38(6): 1033-1040, 2024-The purpose of this study was to assess the effects of a child-specific school-based high-intensity interval training (HIIT) implemented into physical education (PE) classes on various hemodynamic parameters and heart rate variability indices. Forty-six students (age 11 ± 1 year) were randomized into an intervention (INT n = 22) and a control group (CON n = 24). During a 12-week period, the INT and CON groups participated in regular PE twice weekly (45-90 minutes). The INT group received HIIT during the first 20 minutes of the 2 PE classes. Systolic and diastolic blood pressure, total peripheral resistance, aortic pulse wave velocity (aPWV), heart rate, SD of normal to normal heartbeat intervals, the root mean square of successive differences between normal heartbeats (RMSSD), the proportion of differences between adjacent normal to normal heartbeat intervals of more than 50 ms, low-frequency power, high-frequency power, and the LF/HF ratio were assessed before and after the experimental period. A p value ≤0.05 was considered statistically significant. Forty students (20 INT; 20 CON) were included in the analysis. A significant time × group interaction was detected for aPWV ( p = 0.05, η2 = 0.099), RMSSD ( p = 0.010, η2 = 0.161), low-frequency power ( p = 0.009, η2 = 0.165), high-frequency power ( p < 0.001, η2 = 0.272), and the LF/HF ratio ( p < 0.001, η2 = 0.354). The INT group revealed significant improvements for the respective parameters. School-based HIIT can induce improvements in cardiovascular parameters. These results highlight the potential of embedding HIIT within the school setting, offering a time-efficient exercise intervention.

School-based physical activity interventions: which intervention characteristics are associated with participation and retention? A meta-analysis

OBJECTIVE

Many school-based intervention studies are conducted to increase students' physical activity (PA). Recruitment and retention problems potentially impact the robustness of RCT findings. We conducted a meta-analysis to summarize recruitment and retention rates in long-term secondary school-based PA intervention studies and examined associated participant and intervention characteristics.

METHODS

Web of Science, Pubmed, Medline, and PsychInfo were searched until March 20th 2023. We included studies on secondary school-based PA interventions ≥12 weeks, aimed at typically developing adolescents. We abstracted number of schools and students invited, randomized, and participating at follow-up to calculate pooled recruitment and retention rates; participant and intervention characteristics were abstracted to execute subgroup or meta-regression analyses.

RESULTS

Recruitment rates were 51% for invited schools and 80% for invited students, the retention for schools was almost 100% and for students 91%. Interventions with fixed and flexible components, executed in Asia and South America, and from later publication years had higher student recruitment rates. Students' retention rates were lower for interventions which had flexible components, were theory/model-based, used an accelerometer, had a longer intervention duration, and included more females.

CONCLUSION

Recruitment and retention rates in school-based PA interventions are high. Some participant and intervention characteristics influence these rates: flexibility of the intervention, theory/model-based intervention, accelerometer use, intervention duration, continent, and number of females. Researchers should consider these characteristics in intervention development to achieve optimal balance between intervention effectiveness, recruitment, and retention.

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.

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.

A systematic review and cluster analysis approach of 103 studies of high-intensity interval training on cardiorespiratory fitness

AIMS

This study aims to systematically review the systematic reviews and meta-analyses examining the effect of high-intensity interval training (HIIT) protocols on improving cardiorespiratory fitness (CRF) and to characterize the main patterns of HIIT modalities using clustering statistical procedures to examine their potential differences on improving CRF. Finally, we aimed to develop a comprehensive guideline for reporting HIIT protocols.

METHODS AND RESULTS

A systematic review was conducted on PubMed and Web of Science from their inception to 31 October 2022 for systematic reviews and meta-analysis aimed at assessing the effect of HIIT on CRF in the entire study population. The Assessment of Multiple Systematic Reviews 2 tool was used to evaluate the risk of bias of each review. Additionally, a principal component analysis testing the data adequacy for the factor solution through the Kaiser-Meyer-Olkin procedure test was conducted. Once the number of factors was identified, in order to identify data patterns according to the main characteristics of the HIIT protocols, a two-step cluster analysis was conducted. Nineteen systematic reviews and/or meta-analyses comprising 103 studies were included. Clustering of systematic reviews and meta-analyses identified three HIIT modalities ('HIIT-normal mixed', 'HIIT-long running', and 'HIIT-short cycling') underlying the interventions across the included studies. Similar effectiveness in increasing CRF among the three HIIT modalities was observed. Subgroup analyses showed no significant differences in CRF by sex, weight status, study design, and baseline physical activity level (P > 0.05), but differences were observed by age group, and exercise intensity indicator was used in the HIIT programmes (P < 0.05).

CONCLUSION

All three HIIT modalities produced significant improvements of CRF, although some modalities showed greater changes for some specific age groups or intensity indicators.

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.

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.

Making a HIIT: Methods for quantifying intensity in high-intensity interval training in schools and validity of session rating of perceived exertion

Using the data from Making a HIIT, this paper aimed to: 1) investigate the different heart rate (HR) quantification methods reported in school-based high-intensity interval training (HIIT) studies; and 2) assess the criterion validity of session rating of perceived exertion (RPE). During an 8-week HIIT intervention, 213 students (13.1 (0.6) years; 46% female) completed 10-minute HIIT workouts during physical education lessons. In total, 1057 HR and RPE measurements were collected across 68 HIIT workouts. For aim 1, the average and peak HR across all participants and workouts were 79% (8%) and 92% (6%) of HRmax, respectively. The average RPE was 6 (2) points on a 10-point scale. An average of 51% of students in a class had an average HR ≥ 80% for each workout. The between-person variation for peak and average HR were 19% and 30% , respectively. Both average and peak HR decreased by 0.5% each week (p < 0.001). To assess aim 2, a within-participant correlation was calculated for the internal training load produced using HR and RPE data. The correlation was 0.39 (p < 0.001), which suggests utility of using RPE when HR is not a viable option.

Effects of school-based physical activity interventions on physical fitness and cardiometabolic health in children and adolescents with disabilities: a systematic review

Background: This study aimed to examine the influence of school-based physical exercise programs on physical fitness and cardiometabolic health in children and adolescents with disabilities. Methods: Web of Science, Scopus, and PubMed were thoroughly searched to identify relevant investigations. To be included in the systematic review, studies needed to fulfill the following inclusion criteria: 1) performed school-based physical exercise interventions; 2) parameters evaluated referred to health-related physical fitness (HRPF), skill-related physical fitness (SRPF), and cardiometabolic health; 3) a sample of participants consisted of children and adolescents with disabilities; 4) the mean age of respondents was less than 18 years; and 5) were written in the English language. Results: After searching the databases, a total of 474 studies have been identified, 18 of them met the eligibility criteria, and their outcomes were presented. Relating to the respondents' characteristics, the investigations involved 681 children and adolescents with disabilities, out of which 440 were male and 241 female. Regarding types of physical exercise interventions, the most commonly implemented were combined aerobic and resistance training, aerobic exercise, sports games, adapted high-intensity interval training, as well as sprint interval training. The obtained results unambiguously demonstrated that applied exercise interventions improved HRPF components such as cardiorespiratory fitness, muscular fitness, and flexibility. In terms of the SRPF, agility, balance, coordination, and power were considerably enhanced following the school-based exercise. On the other hand, the influence on indices of body composition and cardiometabolic health is quite controversial. The majority of the available studies did not find favorable effects. Additionally, no adverse events were reported in 7 of 8 research, and adherence to exercise was approximately 92%. Conclusion: School-based physical exercise programs were very efficient in improving HRPF and SRPF in children and adolescents with disabilities, while the evidence concerning the variables of body composition and cardiometabolic health is inconclusive and warrants further investigations.

Comparative effectiveness of school-based exercise interventions on physical fitness in children and adolescents: a systematic review and network meta-analysis

Background

Schools provide a favorable setting for health education, however, the most effective school-based exercise mode for improving physical fitness remains unclear. This network meta-analysis was designed to assess and rank the comparative efficacy of six exercise modalities on physical fitness indicators in a school-based setting.

Methods

An online search of the Web of Science, PubMed, SPORTDiscus, and Scopus databases was conducted. Randomized and quasi-randomized controlled trials were considered. Outcomes included measures of anthropometry and body composition, muscular fitness, and cardiorespiratory fitness. Data were pooled with a random effects model using the frequentist framework.

Results

A total of 66 studies with 8,578 participants (48% girls) were included. High-intensity interval training was the most effective intervention reducing body mass index (mean difference (MD) = -0.60 kg·m^-2, 95% confidence interval (95%CI) = -1.04 to -0.15, p = 0.009), elevating VO_2max (MD = 3.59 mL·kg^-1·min^-1, 95% CI = 2.45 to 4.74, p < 0.001), and 20-meter sprint performance (MD = -0.35 s, 95% CI = -0.55 to -0.14, p = 0.001). Aerobic training had the highest probability of reducing waist circumference (standardized mean difference (SMD) = -0.60, 95% CI = -0.88 to -0.32, p < 0.001). Active video games emerged as a promising modality for improving countermovement jump (MD = 2.43 cm, 95% CI = 0.06 to 4.80, p = 0.041) and shuttle running performance (SMD = 0.86, 95% CI = 0.29 to 1.43, p = 0.003). Strength training was the best exercise mode for improving standing long jump performance (SMD = 1.03, 95% CI = 0.07 to 1.98, p = 0.035) while combined training was rated the first for decreasing body fat percent (MD = -2.56%, 95% CI = -4.73 to -0.40, p = 0.022) and increasing push-up repetitions (SMD = 3.59, 95% CI = 0.81 to 6.37, p = 0.012).

Conclusion

School-based exercise interventions have multiple effects on physical fitness. The findings of this study will help to inform physical education teachers and coaches how best to deliver exercise programs in a school setting. Since the study was limited by the original research, the conclusions will require further verification using high-quality randomized controlled trials.

Systematic Review Registration

PROSPERO, Identifier: CRD42023401963.

The effect of 4 weeks of high-intensity interval training and 2 weeks of detraining on cardiovascular disease risk factors in male adolescents

NEW FINDINGS

What is the central question of this study? What is the effect of 4 weeks of high-intensity interval training (HIIT) and 2 weeks of detraining on vascular function and traditional cardiovascular disease (CVD) risk factors in male adolescents? What is the main finding and its importance? Four weeks of HIIT improved macrovascular function in adolescents. However, this training period did not measurably change microvascular function, body composition or blood biomarkers. Following 2 weeks of detraining, the improvement in flow-mediated dilatation (FMD) was lost. This highlights the importance of the continuation of regular exercise for the primary prevention of CVD.

ABSTRACT

High-intensity interval training (HIIT) represents an effective method to improve cardiometabolic health in adolescents. This study aimed to investigate the effect of 4 weeks of HIIT followed by 2 weeks of detraining on vascular function and traditional cardiovascular disease (CVD) risk factors in adolescent boys. Nineteen male adolescents (13.3 ± 0.5 years) were randomly allocated to either a training (TRAIN, n = 10) or control (CON, n = 9) group. Participants in TRAIN completed 4 weeks of HIIT running with three sessions per week. Macro- (flow-mediated dilatation, FMD) and microvascular (peak reactive hyperaemia, PRH) function, body composition (fat mass, fat free mass, body fat percentage) and blood biomarkers (glucose, insulin, total cholesterol, high- and low-density lipoprotein, triacylglycerol) were assessed pre-, 48 h post- and 2 weeks post-training for TRAIN and at equivalent time points for CON. Following training, FMD was significantly greater in TRAIN compared to CON (9.88 ± 2.40% and 8.64 ± 2.70%, respectively; P = 0.036) but this difference was lost 2 weeks after training cessation (8.22 ± 2.47% and 8.61 ± 1.99%, respectively; P = 0.062). No differences were detected between groups for PRH (P = 0.821), body composition (all P > 0.14) or blood biomarkers (all P > 0.18). In conclusion, 4 weeks of HIIT improved macrovascular function; however, this training period did not measurably change microvascular function, body composition or blood biomarkers. The reversal of the FMD improvement 2 weeks post-training highlights the importance of the continuation of regular exercise for the primary prevention of CVD.

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 < 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 < 0.05), and only the B-HIIT improved sit-up muscle endurance (ηp 2 = 0.30, p < 0.05). Conclusion: The B-HIIT protocol was significantly more effective than the R-HIIT protocol in developing CRF and improving muscle health indicators.

Mediating Effect of Motivation on the Relationship of Fitness with Volitional High-Intensity Exercise in High-School Students

We aimed to investigate the relationship between physical fitness and motivation in adolescents and analyze if the associations of physical fitness with volitional exercise intensity in adolescents are mediated by motivation. The participants were 108 adolescents (58 girls 16.0 ± 0.92 years). Cardiorespiratory fitness (CRF) was assessed using the Yo-YoITL1, and the push-up test was used to evaluate strength. Body composition was measured by bioelectrical impedance analysis. The intervention was applied in the first 10-15 min of each Physical Education class (PEC), twice a week, for 16 weeks and ranged from 14 to 20 all-out bouts intervals, adopting a 2:1 work to rest ratio. A cut-point of ≥90% of the maximal heart rate (HR) was used as a criterion for satisfactory compliance with high-intensity exercise. Volition intensity was assessed through a forearm wearable plethysmography heart rate sensor to ensure compliance with the exercise stimulus at the predetermined target HR zone. Motivation was estimated with a validated questionnaire (BREQ-3). Mediation effects were estimated using bootstrapped 95% confidence intervals and were deemed significant if zero was not included in the intervals, and values below 0.05 were considered to indicate statistical significance. The mediation analysis revealed a non-significant indirect effect of physical fitness through motivation on exercise intensity, specifically on CRF (B = -0.0355, 95% BootCI [-0.5838; 0.4559]), muscular fitness (B = -0.7284, 95% BootCI [-2.0272; 0.2219]) and body fat (B = 0.5092, 95% BootCI [-0.4756; 1.6934]). These results suggest that high or low values of motivation did not increase or decrease volitional high-intensity exercise, and lower levels of fitness (CRF, muscular and body fat) were associated with higher volitional exercise intensity. These findings highlight the need for regular moderate-to-vigorous physical exercise for maintaining or improving physical fitness, regardless of motivation regulations, and emphasize the importance of new strategies in PEC with acute vigorous-intensity activities that retain the health-enhancing effects.

The Effect of a 12-Week Physical Functional Training-Based Physical Education Intervention on Students' Physical Fitness-A Quasi-Experimental Study

Children have received much attention in recent years, as many studies have shown that their physical fitness level is on the decline. Physical education, as a compulsory curriculum, can play a monumental role in contributing to students' participation in physical activities and the enhancement of their physical fitness. The aim of this study is to examine the effects of a 12-week physical functional training intervention program on students' physical fitness. A total of 180 primary school students (7-12 years) were invited to participate in this study, 90 of whom participated in physical education classes that included 10 min of physical functional training, and the remaining 90 were in a control group that participated in traditional physical education classes. After 12 weeks, the 50-m sprint (F = 18.05, p < 0.001, ηp2 = 0.09), timed rope skipping (F = 27.87, p < 0.001, ηp2 = 0.14), agility T-test (F = 26.01, p < 0.001, ηp2 = 0.13), and standing long jump (F = 16.43, p < 0.001, ηp2 = 0.08) were all improved, but not the sit-and-reach (F = 0.70, p = 0.405). The results showed that physical education incorporating physical functional training can effectively promote some parameters of students' physical fitness, while at the same time providing a new and alternative idea for improving students' physical fitness in physical education.

Top 10 International Priorities for Physical Fitness Research and Surveillance Among Children and Adolescents: A Twin-Panel Delphi Study

BACKGROUND

The measurement of physical fitness has a history that dates back nearly 200 years. Recently, there has been an increase in international research and surveillance on physical fitness creating a need for setting international priorities that could help guide future efforts.

OBJECTIVE

This study aimed to produce a list of the top 10 international priorities for research and surveillance on physical fitness among children and adolescents.

METHODS

Using a twin-panel Delphi method, two independent panels consisting of 46 international experts were identified (panel 1 = 28, panel 2 = 18). The panel participants were asked to list up to five priorities for research or surveillance (round 1), and then rated the items from their own panel on a 5-point Likert scale of importance (round 2). In round 3, experts were asked to rate the priorities identified by the other panel.

RESULTS

There was strong between-panel agreement (panel 1: r_s = 0.76, p < 0.01; panel 2: r_s = 0.77, p < 0.01) in the priorities identified. The list of the final top 10 priorities included (i) "conduct longitudinal studies to assess changes in fitness and associations with health". This was followed by (ii) "use fitness surveillance to inform decision making", and (iii) "implement regular and consistent international/national fitness surveys using common measures".

CONCLUSIONS

The priorities identified in this study provide guidance for future international collaborations and research efforts on the physical fitness of children and adolescents over the next decade and beyond.

Integrating High-Intensity Interval Training into a School Setting Improve Body Composition, Cardiorespiratory Fitness and Physical Activity in Children with Obesity: A Randomized Controlled Trial

The aim of this study was to examine the effects of school-based high-intensity interval training (HIIT) on cardiorespiratory fitness and visceral adipose tissue (VAT) in children with obesity. A total of 40 students (11.0 ± 0.6 years; 20 boys) were randomized into an intervention group (IG) and control group (CG). The IG group performed a 12-week HIIT intervention with three sessions per week. Each session included 18 min of training (three sets of eight bouts of 15 s run at 100% maximal aerobic speed (MAS) separated by eight bouts of 15 s recovery run at 50% MAS) in PE class; the CG group were instructed to continue their normal behaviors. All subjects had indices of body mass index (BMI), fat mass (FM), body fat percentage (%BF), fat free mass (FFM), VAT, and maximal oxygen uptake (VO2max) measured at baseline and post-intervention. The cooperation of students was high, and all 40 students were included in the final analysis. A significant group−time interaction was determined in body composition (p < 0.05), with a significant decrease in BM (−3.4 ± 1.4 kg, p = 0.001; η2 = 0.63), BMI (−1.7 ± 0.5, p = 0.001; η2 = 0.58), %BF (−3.3 ± 1.4, p = 0.001; η2 = 0.54), and FM (−3.2 ± 1.4 kg, p = 0.001; η2 = 0.69), and VAT (−22.4 ± 9.8 cm2; p = 0.001; η2 = 0.61) in the IG. Furthermore, VO2max exhibited a significant increase in the IG (4.5 ± 1.6 mL/kg/min, p = 0.001; η2 = 0.84) and CG groups (1.7 ± 1.1 mL/kg/min, p = 0.001; η2 = 0.44). Integrating regular school-based HIIT sessions is a suitable method to improve body composition, cardiorespiratory fitness, and physical activity in students with obesity. Trial Registration: ChiCTR2100048737.

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.

Effects of Different Types of High-Intensity Interval Training (HIIT) on Endurance and Strength Parameters in Children and Adolescents

High-Intensity Interval Training (HIIT) promises high training effects on aerobic fitness in children, adolescents and adults in a relatively short time. It is therefore well-established in professional training settings. HIIT methods could also be suited to Physical Education (P.E.) lessons and contribute to students’ health and fitness. Since HIIT sessions need little time and equipment, they can be efficiently implemented in P.E. However, there are few studies which have examined non-running-based HIIT programs in the school sport setting. We therefore conducted an intervention study including 121 students aged 11−15 attending a secondary school in Baden Württemberg, Germany. The effects of three different forms of HIIT training varying in duration and content (4 × 4 HIIT, 12 × 1 HIIT, CIRCUIT) were analyzed. The training was conducted twice a week over 6 weeks (10−12 sessions). Strength and endurance performances were determined in pre- and posttests prior to and after the intervention. Results verified that all three HIIT programs led to significant improvements in aerobic fitness (p < 0.001; part ŋ2 = 0.549) with no significant interaction between time x group. In contrast to the running-based HIIT sessions, CIRCUIT training also led to significant improvements in all of the measured strength parameters. Retrospectively, students were asked to assess their perception of the training intervention. The HIIT sessions were well-suited to students who considered themselves as “athletic”. Less athletic students found it difficult to reach the necessary intensity levels. The evaluation showed that endurance training conducted in P.E. lessons needs a variety of different contents in order to sufficiently motivate students. Students perceiving themselves as “unathletic” may need additional support to reach the required intensities of HIIT. Circuit training sessions using whole-body drills can be efficiently implemented in the P.E. setting and contribute to students’ health and fitness.