High-Intensity Interval Training for Overweight Adolescents: Program Acceptance of a Media Supported Intervention and Changes in Body Composition

The Mediating Effect of Physical Fitness and Dietary Intake on the Relationship of Physical Activity with Body Composition in High School Students

We aimed to investigate the relationship between physical activity (PA) and health-related physical fitness (PF) in adolescents and analyze if the associations of PA with body composition (BC) in adolescents are mediated by physical fitness or energy intake (EI). The participants were 236 adolescents (140 girls 16.1 ± 0.92 years). Cardiorespiratory fitness (CRF) was assessed using the Yo-YoITL1, and the push-up test was used to evaluate strength. BCs were measured on an electrical weight scale. Triaxial accelerometers were used to determine PA levels and moderate-to-vigorous PA (MVPA) levels. EI was estimated with a validated questionnaire. Mediation effects were estimated using bootstrapped 95% confidence intervals and were deemed significant if zero was not included in the intervals. The mediation analysis revealed an indirect effect of MVPA only through PF on BC, specifically through CRF on body fat (B = −0.0146, 95% BootCI (−0.0219; −0.0076)) and on lean body mass (B = 0.0096, 95% BootCI (0.0049; 0.0152)), as well as through upper body strength on body fat (B = −0.012, 95% BootCI (−0.0171; −0.0072)) and on lean body mass (B = 0.0059, 95% BootCI (0.003; 0.0095)). These results suggest that PA of at least a moderate intensity is relevant to BC and health-related PF in adolescents, regardless of the EI.

High-intensity interval training in high-school physical education classes: Study protocol for a randomized controlled trial

Background

School and Physical Education classes (PEC) are privileged spaces, promoters of positive changes for the rest of life. High-Intensity Interval Training (HIIT) is presented as a time-efficient alternative to aerobic training, as it leverages the number of exercise participants, resulting in improvements in health outcomes. Despite the widespread interest in the advantages that the HIIT methodology reveals, there is a lack of randomized controlled studies investigating the impact on adolescents, mainly adressing adolescents’ environment, such as schools. This study aims to evaluate the utility of a HIIT program integrated into high-school PEC, as a strategy that allows students to improve their Physical Fitness, Physical Activity (PA) level, and Motivation for Exercise.

Methods

This study is a two-arm randomized controlled trial design with adolescents from the 10th to 12th grades (15–17 years). The trial will aim to recruit 300 students from 1 secondary school. The HIIT sessions will be applied in the first 10–15 min of each PEC, twice a week, for 16 weeks, ranged from 14 to 20 all-out bouts intervals, adopting a 2:1 work to rest ratio. A cut-point of ≥ 90% of maximal heart rate will be a criterion for satisfactory compliance to high-intensity exercise. A rated perceived exertion scale will be measured in each exercise session to estimate effort, fatigue, and training load. The control group will continue the usual programmed PEC. Study outcomes will be measured at baseline and after the HIIT program. Cardiorespiratory fitness is the primary outcome. Secondary outcomes include: muscular fitness, PA and motivation for exercise.

Discussion

HIIT protocols presents wide applicability in PEC and great adaptation to the facilities. The authors aim to provide novel HIIT protocols for schools.

Evidence-Based Effects of High-Intensity Interval Training on Exercise Capacity and Health: A Review with Historical Perspective

Engaging in regular exercise results in a range of physiological adaptations offering benefits for exercise capacity and health, independent of age, gender or the presence of chronic diseases. Accumulating evidence shows that lack of time is a major impediment to exercise, causing physical inactivity worldwide. This issue has resulted in momentum for interval training models known to elicit higher enjoyment and induce adaptations similar to or greater than moderate-intensity continuous training, despite a lower total exercise volume. Although there is no universal definition, high-intensity interval exercise is characterized by repeated short bursts of intense activity, performed with a "near maximal" or "all-out" effort corresponding to ≥90% of maximal oxygen uptake or >75% of maximal power, with periods of rest or low-intensity exercise. Research has indicated that high-intensity interval training induces numerous physiological adaptations that improve exercise capacity (maximal oxygen uptake, aerobic endurance, anaerobic capacity etc.) and metabolic health in both clinical and healthy (athletes, active and inactive individuals without any apparent disease or disorder) populations. In this paper, a brief history of high-intensity interval training is presented, based on the novel findings of some selected studies on exercise capacity and health, starting from the early 1920s to date. Further, an overview of the mechanisms underlying the physiological adaptations in response to high-intensity interval training is provided.

Mobile Health for Pediatric Weight Management: Systematic Scoping Review

BACKGROUND

The prevalence and consequences of obesity among children and adolescents remain a leading global public health concern, and evidence-based, multidisciplinary lifestyle interventions are the cornerstone of treatment. Mobile electronic devices are widely used across socioeconomic categories and may provide a means of extending the reach and efficiency of health care interventions.

OBJECTIVE

We aimed to synthesize the evidence regarding mobile health (mHealth) for the treatment of childhood overweight and obesity to map the breadth and nature of the literature in this field and describe the characteristics of published studies.

METHODS

We conducted a systematic scoping review in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews, by searching nine academic databases in addition to gray literature for studies describing acceptability, usability, feasibility, effectiveness, adherence, or cost-effectiveness of interventions assessing mHealth for childhood obesity treatment. We also hand searched the reference lists of relevant articles. Studies aimed at the prevention of overweight or obesity were excluded, as were studies in which mHealth was not the primary mode of treatment delivery for at least one study arm or was not independently assessed. A random portion of all abstracts and full texts was double screened by a second reviewer to ensure consistency. Data were charted according to study characteristics, including design, participants, intervention content, behavior change theory (BCT) underpinning the study, mode of delivery, and outcomes measured.

RESULTS

We identified 42 eligible studies assessing acceptability (n=7), usability (n=2), feasibility or pilot studies (n=15), treatment effect (n=17), and fidelity (n=1). Change in BMI z-scores or percentiles was most commonly measured, among a variety of dietary, physical activity, psychological, and usability or acceptability measures. SMS, mobile apps, and wearable devices made up the majority of mobile interventions, and 69% (29/42) of the studies specified a BCT used.

CONCLUSIONS

Pediatric weight management using mHealth is an emerging field, with most work to date aimed at developing and piloting such interventions. Few large trials are published, and these are heterogeneous in nature and rarely reported according to the Consolidated Standards of Reporting Trials for eHealth guidelines. There is an evidence gap in the cost-effectiveness analyses of such studies.

Effects of Telephone Aftercare Intervention for Obese Hispanic Children on Body Fat Percentage, Physical Fitness, and Blood Lipid Profiles

We investigated effects of 10-month telephone aftercare intervention following primary obesity intervention on changes in body fat percentage, physical fitness, and lipid profiles in obese Hispanic children. Seventy-one obese children were randomly assigned to (1) primary intervention and 10-month telephone aftercare intervention (PITI; N = 26), (2) primary intervention only (PI; n = 25), and (3) control (CON; N = 20). Anthropometric data, physical fitness, and blood samples were obtained before (PRE) and after (POST) eight-week primary intervention, and 10-month telephone aftercare intervention (1YEAR). Eight weeks of primary intervention significantly reduced body fat percentage, total cholesterol, triglycerides, and low-density lipoprotein (LDL-C) with increases in VO_2max, flexibility, muscular strength, and HDL-C (PITI and PI, p < 0.05). 1YEAR measurements returned to baseline for the PI whereas those measurements in PITI remained significantly different when compared to PRE (p < 0.05). CON observed negative changes in all variables at POST, which were improved slightly during the subsequent school year. Levels of cholesterol, triglycerides, and LDL-C are correlated to changes in body fat percentage, suggesting that fat loss is effective in preventing and managing obesity-related disorders. Results indicate that telephone intervention is an effective aftercare in stabilizing positive changes obtained from a short-term intensive intervention.

Effects of Telephone Follow-Up Intervention on %Body Fat, Inflammatory Cytokines, and Oxidative Stress in Obese Hispanic Children

This study investigated whether 10 month telephone follow-up intervention effectively stabilizes reductions in %body fat, and markers of inflammation and oxidative stress obtained from summer camp in obese Hispanic children. Fifty-six obese children (19 SUTI: summer camp and 10 months of follow-up telephone intervention, 18 SU: summer camp intervention only, and 19 CON: no intervention) completed this study. Anthropometric data and blood samples were obtained before (PRE), after 8 weeks of summer camp, and a 10month follow-up telephone intervention to measure markers of inflammation and oxidative stress. Eight weeks of summer camp significantly reduced %body fat, and levels of tumor necrosis factor-alpha, C-reactive protein and 8-hydroxydeoxyguanosine. It also elevated levels of adiponectin and total antioxidant status in SUTI and SU (p < 0.05). However, results of the 10month follow-up measurement were reverted back to PRE in SU, whereas the results for SUTI remained different to PRE (p < 0.05). Results confirm that levels of inflammation and oxidative stress are correlated to changes in %body fat, indicating that fat loss is effective in preventing and managing obesity-associated disorders. It is suggested that a telephone intervention is an effective follow-up tool for stabilizing reductions in %body fat as well as levels of inflammation and oxidative stress that were obtained from an intensive summer camp program in obese Hispanic children.

Reliability of Submaximal Yo-Yo Tests in 9- to 16-Year-Old Untrained Schoolchildren

PURPOSE

To examine the reliability of age-adapted submaximal Yo-Yo (Yo-Yo_submax) intermittent tests in untrained schoolchildren aged 9-16 years (n = 139; 72 boys and 67 girls) and within children with high and low percentage of body fat (%BF).

METHODS

Yo-Yo intermittent recovery level 1 children's (YYIR1C), Yo-Yo intermittent endurance level 1 (YYIE1), and Yo-Yo intermittent endurance level 2 (YYIE2) tests were performed 7 days apart by 9- to 11-, 12- to 13-, and 14- to 16-year-old children, respectively. Reliability was tested for Yo-Yo_submax heart rate (HR_submax), peak HR, and maximal distance.

RESULTS

HR_submax typical errors of measurement (TEM) in YYIR1C, YYIE1, and YYIE2 were 2.2% (1.7%-2.9%), 2.4% (1.9%-3.3%), 1.9% (1.6%-2.5%) and 2.4% (1.9%-3.3%), 2.4% (1.9%-3.2%), 1.9% (1.5%-2.4%) for girls and boys, respectively. HR_submax intraclass correlation coefficient values were good to excellent (.62-.87) in all age groups and in schoolchildren of different %BF. TEM for HR_submax ranged from 2.1% to 2.3% in high and low %BF groups. Maximal distance intraclass correlation coefficients were excellent and TEM values ranged from 11% to 12% in both %BF groups. HR_submax was moderately to largely associated (r = -.46 to -.64; P < .002) with Yo-Yo maximal distance across the age groups.

CONCLUSION

Yo-Yo_submax tests are a reliable tool providing useful and sustainable aerobic performance testing in physical education, irrespective of individual %BF.

High-intensity interval training in overweight and obese children and adolescents: systematic review and meta-analysis

INTRODUCTION

While High Intensity Interval Training is praised in many populations for its beneficial effects on body composition and cardiometabolic health, its use among obese youth remain uncertain. This study aimed at determining whether HIIT is effective to improve aerobic fitness and reduce cardiometabolic risk factors in overweight and obese youth.

EVIDENCE ACQUISITION

A systematic search was conducted and articles reporting studies that investigated the effects of HIIT in 6 to 18-year-old youth were eligible. Meta-analyses were performed when appropriate.

EVIDENCE SYNTHESIS

Fifteen studies were included for the systematic review and meta-analyses. HIIT significantly improves maximal oxygen uptake (1.117 [95% CI: 0.528 to 1.706], P<0.001), and reduces body mass (-0.295 [95% CI: -0.525 to -0.066], P<0.05), body fat (-0.786 [95% CI: -1.452 to -0.120], P<0.05), systolic and diastolic blood pressure (-1.026 [95% CI: -1.370 to -0.683], P<0.001; -0.966 [95% CI: -1.628 to -0.304], P<0.01 respectively), and the HOMA-IR (-1.589 [95% CI: -2.528 to -0.650], P<0.01). However, there is significant heterogeneity, and low to high inconsistency for most cardiometabolic risk factors and aerobic fitness.

CONCLUSIONS

Although few studies have reported cardiometabolic risks, HIIT may also be as effective as traditional endurance continuous training to decrease blood pressure and insulin resistance. HIIT is effective to improve aerobic fitness, body composition, and cardiometabolic risk factors in obese youth, but data are insufficient to determine whether it is more effective than traditional continuous submaximal intensity exercise training.

Cardiometabolic risk markers, adipocyte fatty acid binding protein (aFABP) and the impact of high-intensity interval training (HIIT) in obese adolescents

OBJECTIVE

The impact of high-intensity interval training (HIIT) as well as the association between the adipocyte fatty binding protein (aFABP) and cardiometabolic risk factors in overweight adolescents was investigated.

METHODS

Twenty-eight adolescents (13-18years; BMI≥90th percentile according to German reference values) were offered HIIT twice weekly for 6months. At baseline and after program completion, anthropometric, clinical and metabolic characteristics were assessed and a fasting blood sample was obtained. Leptin, adiponectin, visfatin and aFABP were measured using commercially available kits. DNA methylation at RALBP1 was assessed using pyrosequencing. Descriptive statistics, Pearson's correlation and linear models were calculated.

RESULTS

Mean age at start of the program was 15.5±1.4years (53.5% females) and 20/28 (71%) provided follow-up data. At baseline, aFABP was correlated with BMI-SDS (0.48 [0.13,0.72]; p=0.0095), waist-to-height-ratio (0.63 [0.33,0.81], p=0.00036) and body fat content (0.55 [0.21, 0.77]; p=0.0031). Certain markers of metabolic risk were significantly correlated with aFABP (HOMA-IR 0.52 [0.19, 0.75], p=0.0044; γGT 0.48 [0.13, 0.73], p=0.0091; uric acid 0.46 [0.11, 0.71] p=0.013; HDL-C -0.39 [-0.66, -0.01] p=0.043; triglycerides 0.38 [0.01, 0.66], p=0.047). With the exception of triglycerides, these associations vanished after adjusting for BMI-SDS. aFABP did not depend on sex, age or pubertal stage in obese adolescents. After the HIIT program, small but significant reductions were observed in waist-to-height-ratio, (0.013 [0.0025, 0.024]; p=0.023), skin-fold based body fat content (2.0% [0.6, 3.5]; p=0.011), and standard deviation score of systolic blood pressure (0.69 [0.26 to 1.1]; p=0.0036). No changes were observed in adipokines or epigenetic markers following the program.

CONCLUSION

HIIT may have beneficial effects on body composition and cardiometabolic health in overweight adolescents. Like in adults, aFABP seems to be associated with markers of metabolic risk in obese adolescents.