Exercise dose on hepatic fat and cardiovascular health in adolescents with excess of adiposity

Solving the High-Intensity Multimodal Training Prescription Puzzle: A Systematic Mapping Review

BACKGROUND

High-Intensity Multimodal Training (HIMT) refers to all styles of high-intensity combined aerobic, resistance and/or bodyweight exercise. Previous heterogeneity in exercise prescription and reporting in HIMT reduces the understanding of which factors should be considered when prescribing HIMT (e.g., exercise volume, intensity, duration). Previous studies have demonstrated positive effects of HIMT on health and performance outcomes. However, methodological disparities limit comparisons between findings. The objective of this systematic mapping review was to examine which prescriptive considerations and health and performance outcomes have been reported on in HIMT. This review also examined the quantity and trends of research conducted on HIMT.

METHODS

A systematic literature search was conducted using Ovid Medline, SPORTDiscus and Cochrane Library databases and additional sources to identify studies up until February 2023. A total of 37,090 records were retrieved, of which 220 were included for review. 246 individual HIMT protocols were included for categorical analysis against the Consensus on Exercise Reporting Template (CERT) and Applied Research Model for the Sport Sciences (ARMSS).

RESULTS

A total of 85 unique terms were used to describe HIMT. Included studies most commonly prescribed HIMT using a consistent exercise selection and circuit format. Exercise intensity was inconsistently reported on and a large proportion of studies prescribed 'high-intensity' exercise at a level lower than the American College of Sports Medicine criteria for high-intensity (i.e., < 77% heart rate maximum). Participation location, supervision and participation format were the most commonly reported non-training variables. The most frequently reported outcomes were cardiovascular health, perceptual outcomes, body composition and biochemical outcomes. A large proportion of previous HIMT research was experimental in design.

CONCLUSIONS

Previous HIMT research demonstrates a lack of standardisation in reporting. Future studies should seek to follow guidelines (i.e., CERT) to improve reporting rigour. Additionally, forthcoming research should attempt to actively involve practitioners in implementation studies to improve ecological validity among interventions. Finally, future outcome measures should be accessible in practice and reflect common training goals of participants.

REGISTRATION

This review adhered to PRISMA-ScR guidelines.

PREREGISTRATION

osf.io/yknq4.

Dose-response relationship between physical activity and cardiometabolic risk in obese children and adolescents: A pre-post quasi-experimental study

Objective: This study aims to explore the dose-response relationship between the daily duration of moderate to vigorous physical activity and the improvement of cardiometabolic risk indicators in obese children and adolescents. Methods: Seventy-seven obese children and adolescents aged 10-17 years were randomly recruited for a 4-week exercise intervention in a closed camp during 2019-2021, physical activity was monitored by ActiGraph GT3X + to obtain daily MVPA duration, and the improvement of CMR indicators were reflected by the changes (Δ) of waist circumference, systolic blood pressure, diastolic blood pressure, total cholesterol, triglyceride , high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting insulin, fasting plasma glucose, and homeostasis model assessment of insulin resistance before and after the intervention, calculated as ''Δ+indicator" = values after intervention-values before intervention. The groups were divided into different doses of Q1∼Q3 according to the daily MVPA duration from low to high. The differences in the improvement of different dose groups were compared by one-way analysis of covariance, and the dose-response relationship between MVPA duration and CMR indicators improvement was analyzed by linear regression and piecewise regression. The nonlinear relationship was analyzed by restricted cubic spline. Results: 1) Compared with indicators before the intervention, WC, SBP, DBP, TC, TG, HDL-C, LDL-C, FINS, and HOMA-IR were significantly lower after the intervention (p-value < 0.05). 2) The dose-response relationship between MVPA and LDL-C improvement was non-linear (P-Nonlinear < 0.05). When MVPA >77.1min/day, ΔLDL-C further decreased with the increase of MVPA duration [β = -0.009, 95% confidence interval (CI): -0.013, -0.005], and when MVPA ≤77.1min/day, increasing the MVPA duration did not increase the improvement of ΔLDL-C. Conclusion: There was a nonlinear dose-response relationship between the daily MVPA duration and LDL-C improvement in obese children and adolescents. In order to obtain more significant improvement in LDL-C through increased MVPA duration, MVPA duration should be higher than 77.1 min/day.

Association between alanine aminotransferase as surrogate of fatty liver disease and physical activity and sedentary time in adolescents with obesity

To compare patterns of sedentary (SED) time (more sedentary, SED + vs less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA + vs less active, MVPA-), and combinations of behaviors (SED-/MVPA + , SED-/MVPA-, SED + /MVPA + , SED + /MVPA-) regarding nonalcoholic fatty liver diseases (NAFLD) markers. This cross-sectional study included 134 subjects (13.4 ± 2.2 years, body mass index (BMI) 98.9 ± 0.7 percentile, 48.5% females) who underwent 24-h/7-day accelerometry, anthropometric, and biochemical markers (alanine aminotransferase (ALT) as first criterion, and aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), AST/ALT ratio as secondary criteria). A subgroup of 39 patients underwent magnetic resonance imaging-liver fat content (MRI-LFC). Hepatic health was better in SED- (lower ALT, GGT, and MRI-LFC (p < 0.05), higher AST/ALT (p < 0.01)) vs SED + and in MVPA + (lower ALT (p < 0.05), higher AST/ALT (p < 0.01)) vs MVPA- groups after adjustment for age, gender, and Tanner stages. SED-/MVPA + group had the best hepatic health. SED-/MVPA- group had lower ALT and GGT and higher AST/ALT (p < 0.05) in comparison with SED + /MVPA + group independently of BMI. SED time was positively associated with biochemical (high ALT, low AST/ALT ratio) and imaging (high MRI-LFC) markers independently of MVPA. MVPA time was associated with biochemical markers (low ALT, high AST/ALT) but these associations were no longer significant after adjustment for SED time.

CONCLUSION

Lower SED time is associated with better hepatic health independently of MVPA. Reducing SED time might be a first step in the management of pediatric obesity NAFLD when increasing MVPA is not possible.

WHAT IS KNOWN

• MVPA and SED times are associated with cardiometabolic risks in youths with obesity. • The relationships between NAFLD markers and concomitant MVPA and SED times have not been studied in this population.

WHAT IS NEW

• Low SED time is associated with healthier liver enzyme profiles and LFC independent of MVPA. • While low SED/high MVPA is the more desirable pattern, low SED/low MVPA pattern would have healthier liver enzyme profile compared with high MVPA/high SED, independent of BMI, suggesting that reducing SED time irrespective of MVPA is needed to optimize liver health.

Associations between physical fitness components with muscle ultrasound parameters in prepuberal children

BACKGROUND/OBJECTIVES

Muscle ultrasound is a convenient technique to visualize normal and pathological muscle tissue as it is non-invasive and real-time. This technique is related to several physical performance parameters and body composition components in adults; however, this relationship remains unexplored in early aged. We aimed to evaluate the association between physical fitness components with muscle ultrasound parameters in prepuberal children.

METHODS

A sample of 282 prepuberal children aged 5-9 years (144 boys) participated in the study. A trained sonographer obtained six B-mode images from femoral rectus for muscle thickness, subcutaneous adipose tissue (SAT) and area of the muscle of interest, were captured, and muscle ultrasound parameters (echo-intensity: EI _uncorrected, EI _{correct equations}) and intramuscular adipose tissue (IMAT) were extracted. Lean muscle tissue has low EI, whereas intramuscular fat and connective tissue have high EI. Physical fitness components (cardiorespiratory fitness, upper and lower muscle strength, speed-agility, and overall fitness levels) were also evaluated. Children were categorized as fit or unfit for each specific fitness test.

RESULTS

After adjustment for sex and age, higher physical fitness components and overall fitness (z-score) levels were negatively associated with EI, IMAT, and SAT (cardiorespiratory fitness β range = -0.264 to -0.298; upper-muscular strength β range = -0.389 to -0.457; and lower-muscular strength β range = -0.202 to -0.279; and speed-agility β range = -0.257 to -0.302). Children categorized as fit according to four physical fitness components had lower EI _uncorrected, EI _{correct equation 1-2}, IMAT, and SAT than unfit children for each respective tests (all Ps < 0.001).

CONCLUSION

Physical fitness components are inversely associated with EI, IMAT, SAT after adjusting for potential confounders, including sex and age, in prepuberal children. The present study strengthens the idea that muscle and adiposity parameters is affected by physical fitness even from early childhood.