Metabolic effects of resistance or high-intensity interval training among glycemic control-nonresponsive children with insulin resistance

Effects and individual response of continuous and interval training on adiponectin concentration, cardiometabolic risk factors, and physical fitness in overweight adolescents

This study aimed to evaluate the effect and individual responsiveness after 12 weeks of high-intensity interval training (HIIT) and moderate-intensity of continuous training (MICT) on adiponectin, cardiometabolic risk factors and physical fitness in overweight adolescents. This study was participated by 52 adolescents, both sexes, 11 and 16 years old, separated into HIIT (n = 13), MICT (n = 15), and control group (CG, n = 24). Body mass, height, waist circumference (WC), fat mass (FM), fat-free mass (FFM), blood pressure, high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c), triglycerides, glucose, insulin, adiponectin, and C-reactive protein (CRP) were evaluated. Body mass index z-score (BMI-z), waist-to-height ratio (WHtR), insulin resistance, and insulin sensitivity were calculated. Resting heart rate (HR_rest), peak oxygen consumption (VO_2peak), right handgrip strength (HGS-right), left handgrip strength (HGS-left), and abdominal resistance (ABD) was evaluated. HIIT session lasted around 35 min and MICT of 60 min of exercises on stationary bicycle, three times a weekday for 12 weeks. ANOVA, effect size, and prevalence of responders were used for statistical analysis. HIIT reduced BMI-z, WHtR, LDL-c, and CRP, while increased of physical fitness. MICT reduced HDL-c, while increased of physical fitness. CG reduced FM, HDL-c, and CRP, while increased FFM and HR_rest. Frequencies of respondents in HIIT were observed for CRP, VO_2peak, HGS-right, and HGS-left. Frequencies of respondents in MICT were observed for CRP and HGS-right. Frequencies of no-respondents in CG were observed for WC, WHtR, CRP, HR_rest, and ABD.  Conclusion: Interventions with exercises were effective to adiposity, metabolic health, and physical fitness improvements. Individual responses were observed in inflammatory process and physical fitness, important changes in overweight adolescent's therapy.  Trial registration number and date of registration: This study was registered with the Brazilian Registry of Clinical Trials (REBEC), the number RBR-6343y7, date of registration May 3, 2017. What is Known: • Effect of regular physical exercise positively affects overweight, comorbidities, and metabolic diseases, recommended mainly for children and adolescents. What is New: • Due to the great inter-individual variability, the same stimulus can provide different responses; adolescents who benefit from the stimulus are considered responsive. • Intervention of HIIT and MICT did not alter the concentrations of adiponectin; however, the adolescents presented responsiveness to the inflammatory process and physical fitness.

EFFECTS OF A SMALL-SIDED SOCCER PROGRAM ON HEALTH PARAMETERS IN OBESE CHILDREN

ABSTRACT Introduction: Childhood obesity is increasing and, as a consequence, it generates health complications resulting from sedentary behavior and low levels of physical fitness. There are few studies involving children, metabolic and cardiorespiratory profiles, and soccer. Objective: The purpose was to measure the effects of a 12-week recreational small-sided soccer program on cardiometabolic risk and individual responses to cardiometabolic risk factors in overweight or obese boys. Methods: Thirteen boys aged 8-12 years (34.9±11.6% body fat) participated in a 12-week recreational small-sided soccer training program with two 80-minute sessions per week at intensities over 80% of the maximal heart rate. Anthropometric characteristics, cardiorespiratory fitness, metabolic profile, individual responses to peak oxygen uptake (VO2peak), maximal workload (Wmax), fasting blood glucose, insulin, HOMA-IR, LDL-C, HDL-C, TC, and TG were measured both pre- and post-training. Results: Considering the individual responses of the participants, recreational soccer training was effective in improving variations in maximum power and exhaustion time, as well as promoting at least one beneficial change in cardiometabolic risk factors in 84% of the overweight or obese children. There were no differences between pre- and post-program anthropometric characteristics, metabolic profiles, or VO2peak values. Conclusion: Twelve-week recreational small-sided soccer programs were able to improve maximal power and anaerobic capacity and maintain cardiometabolic risk factor levels in overweight and obese boys. Level of evidence I; High-quality prospective study (all patients were enrolled at the same stage of disease, with >80% of patients enrolled) .

A descriptive ranking of blood pressure and physical fitness of Latin-American ethnic schoolchildren

BACKGROUND

There is a general lack of information about how insufficient physical activity impacts blood pressure and physical fitness in Latin-American ethnic minorities.

AIMS

To describe the interactions between insufficient physical activity, blood pressure, and physical fitness outcomes in Latin-American schoolchildren of different ethnicity.

METHODS

This was a prospective, international, multi-center, and cross-sectional study of three Latin-American countries involving schoolchildren from seven ethnic groups of Colombia (Tikuna, Nasa, Embera), Brazil (African, Mulato), and Chile (Mapuche), and also European schoolchildren from Brazil and Chile. Data were categorized based on whether participants were physically active (PA) or insufficient physical activity (iPA) using the WHO physical activity recommendations. The main outcomes were systolic (SBP), diastolic (DBP), and mean arterial (MAP) blood pressure, and scores for physical and cardiorespiratory fitness (CRF, by estimated V˙O₂max), handgrip muscle strength (HGS), and standing long jump (SLJ). Secondary outcomes were anthropometric measures (weight, height, body mass index [BMI], waist circumference [WC], waist-to-height ratio), and body fat percentage (BF%, limited data by country). Primary and secondary outcomes were ranked.

RESULTS

For both PA and iPA categories, significant interactions between ethnic groups were found concerning SBP/DBP (F_(37.7), ES 0.08; F_(51.5), ES 0.08), V˙O₂max (F_(37.7), ES 0.08; F_(51.5), ES 0.08), HGS (F_(33.8), ES 0.07; F_(5.03), ES 0.04), and SLJ (F_(64.3), ES 0.14; F_(64.3), 0.14). In the iPA category, Mapuche schoolchildren were classified 1st (119.5; 81.5) with highest SBP/DBP and highest MAP (94.6 mmHg); Embera schoolchildren were classified 1st with lowest V˙O₂max (33.7 mL/kg/min); and European schoolchildren were classified 1st (19.9 kg) with lowest HGS and SLJ (121.4 m) physical fitness.

CONCLUSIONS

Under conditions of insufficient physical activity conditions, Mapuche schoolchildren had the most detrimental blood pressure, whereas Embera, Tikuna, and European schoolchildren had the lowest levels of physical fitness. These results serve to highlight the need for the early and appropriate promotion of physical activity based on ethnic differences in Latin-American schools.

Physical function, body mass index, and fitness outcomes in children, adolescents, and emerging adults with craniopharyngioma from proton therapy through five years of follow-up

Purpose

Children diagnosed with craniopharyngioma are vulnerable to adverse health outcomes. Characterization of body mass index (BMI), physical function, and cardiopulmonary fitness in those treated with proton radiotherapy (PRT) will serve to design interventions to improve outcomes.

Methods

Ninety-four children with craniopharyngioma completed physical function testing prior to PRT and annually for 5 years. For each outcome, age- and sex-specific z-scores were calculated using normative values. Participants with z-scores > 1.5 or < − 1.5 were classified as impaired. Those with z-scores > 2.0 or < − 2.0 were classified as significantly impaired. Descriptive statistics were used to describe study outcomes and change in prevalence of impairments from 2 to 5 years after treatment.

Results

Nearly half of participants [45.2%, 95% confidence interval (CI) 39.4, 51.0] had mean BMI z-scores > 1.5 at baseline, with prevalence increasing to 66.7% (95% CI 61.5, 71.9) at 5 years. More than half of participants (54.2%, 95% CI 48.4, 60.0) had knee extension strength z-scores < − 1.5 at baseline, with prevalence increasing to 81.3% (95% CI 77.7, 84.9) at 5 years. BMI and knee extension strength had the largest proportion of participants impaired at both 2 and 5 years (53.2% and 62.3%, respectively). Resting heart rate had the highest proportion of participants not impaired at 2 years but became impaired at 5 years (26.6%).

Conclusions

Children with craniopharyngioma have BMI and fitness abnormalities at diagnosis and continue 5 years after treatment. This cohort may benefit from interventions designed to improve BMI, strength, and resting indicators of cardiopulmonary fitness.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11060-022-04116-2.

Responsiveness on metabolic syndrome criteria and hepatic parameters after 12 weeks and 24 weeks of multidisciplinary intervention in overweight adolescents

PURPOSE

This study aimed to evaluate the effect and individual responsiveness after 12 (12wk) and 24 weeks (24wk) of physical exercise (PE) and nutritional guidance (NG) on metabolic syndrome (MetS) criteria and hepatic parameters in overweight adolescents.

METHODS

The study comprised 94 overweight adolescents, aged between 10 and 16 years old, from both sexes, allocated into groups: PE and NG (PENGG, n = 64) and control with NG (NGCG, n = 30). Variables were collected at baseline, 12wk, and 24wk. Weight, height, abdominal circumference (AC), blood pressure, and peak oxygen consumption (VO_2peak), as well as insulin, triglycerides (TAG), high-density lipoprotein (HDL-c), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were evaluated. HOMA-IR and QUICKI were calculated. PE session consisted of 45 min of indoor cycling, 45 min of walking, and 20 min of stretching, three times a week. The NG consisted of three collective sessions in the first 12wk. Anova, effect size, and prevalence of responders were used for statistical analysis.

RESULTS

The PENGG12wk reduced anthropometric and metabolic measurements, while increased VO_2peak and HDL-c. The PEG24wk promoted anthropometric, blood pressure, metabolic, and VO_2peak improvements, but participants without PE returned to pre-exercise status and presented worsening AST and ALT concentrations. Frequencies of respondents in PENGG12wk versus (vs) NGCG12wk were, respectively, AC (69.1% vs 17.6%, p < 0.01), HDL-c (87.2% vs 23.5%, p < 0.01), TAG (67.3% vs 41.7%, p = 0.05) and ALT (45.5% vs 5,9%; p = 0.003).

CONCLUSION

Interventions with PE were effective to reduce MetS components in 12wk and maintenance in 24wk, showing anthropometric, metabolic, and VO_2peak improvements. Higher individual responses were observed in 12wk and in 24wk, important changes in overweight adolescent's therapy.

LEVEL OF EVIDENCE

Level I, evidence obtained from well-designed controlled trials randomization.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

Brazilian Registry of Clinical Trials (RBR-4v6h7b) and date of registration April 4th, 2020.

Handgrip strength cut-off points for early detection of cardiometabolic risk in Chilean children

The aim of this study was to determine whether handgrip strength is associated with cardiometabolic risk in children. The secondary aim was to establish sex-specific handgrip strength cut-off points for early detection of cardiometabolic risk. A total sample of 452 Chilean children (267 girls and 185 boys) aged 7-9 years old was analyzed. Muscle fitness was measured by an adjustable dynamometer and normalized by body mass (i.e., handgrip strength/body mass). Sex-specific cardiometabolic risk scores were computed as the sum of the waist-to-height ratio (Equation 1) or waist circumference (Equation 2) and insulin, triglycerides, high-density lipoproteins, and glycemia levels. Receiver operating curve (ROC) analyses were performed to identify those with cardiometabolic risk scores > 1 standard deviation above the mean. ROC analyses showed a significant discriminating accuracy of normalized handgrip strength in identifying cardiometabolic risk in boys (≤ 0.33) and girls (≤ 0.40) using both equations. The highest sensitivity was offered by Equation 2 for boys [46%; 95% CI (32-59%)] and for girls [71%; 95% CI (60-80)]. The greatest specificity was also offered by Equation 2 for boys [82%; 95% CI (74-88)] and girls [63%; 95% CI (55-70)]. Since the values obtained by ROC analyses are low (especially in boys), caution is warranted regarding the strength of the existing evidence base.Conclusion: These specific cut-off points according to sex for possible cardiometabolic risk could be used by Chilean health professionals and school staff as an initial assessment in the field setting. What is known • There is strong evidence for the importance of muscular fitness during childhood and adolescence for cardiometabolic risk. • There has been no research to establish minimum handgrip strength capacity levels to predict cardiometabolic risk among Chilean children. What is new • Cut-off points for handgrip strength relative to body mass to identify cardiometabolic risk in Chilean children are 0.33 in boys and 0.40 in girls. • The early use of these cut-off points and its appropriate identification could have benefits of preventive and diagnostic therapeutic intervention and as a starting point to define adequate levels of handgrip strength.

A Systematic Review Examining the Approaches Used to Estimate Interindividual Differences in Trainability and Classify Individual Responses to Exercise Training

Background: Many reports describe statistical approaches for estimating interindividual differences in trainability and classifying individuals as "responders" or "non-responders." The extent to which studies in the exercise training literature have adopted these statistical approaches remains unclear. Objectives: This systematic review primarily sought to determine the extent to which studies in the exercise training literature have adopted sound statistical approaches for examining individual responses to exercise training. We also (1) investigated the existence of interindividual differences in trainability, and (2) tested the hypothesis that less conservative thresholds inflate response rates compared with thresholds that consider error and a smallest worthwhile change (SWC)/minimum clinically important difference (MCID). Methods: We searched six databases: AMED, CINAHL, EMBASE, Medline, PubMed, and SportDiscus. Our search spanned the aerobic, resistance, and clinical or rehabilitation training literature. Studies were included if they used human participants, employed standardized and supervised exercise training, and either: (1) stated that their exercise training intervention resulted in heterogenous responses, (2) statistically estimated interindividual differences in trainability, and/or (3) classified individual responses. We calculated effect sizes (ES_IR) to examine the presence of interindividual differences in trainability. We also compared response rates (n = 614) across classification approaches that considered neither, one of, or both errors and an SWC or MCID. We then sorted response rates from studies that also reported mean changes and response thresholds (n = 435 response rates) into four quartiles to confirm our ancillary hypothesis that larger mean changes produce larger response rates. Results: Our search revealed 3,404 studies, and 149 were included in our systematic review. Few studies (n = 9) statistically estimated interindividual differences in trainability. The results from these few studies present a mixture of evidence for the presence of interindividual differences in trainability because several ES_IR values lay above, below, or crossed zero. Zero-based thresholds and larger mean changes significantly (both p < 0.01) inflated response rates. Conclusion: Our findings provide evidence demonstrating why future studies should statistically estimate interindividual differences in trainability and consider error and an SWC or MCID when classifying individual responses to exercise training. Systematic Review Registration: [website], identifier [registration number].

Weightlifting for Children and Adolescents: A Narrative Review

The involvement of youth in the sport of weightlifting and the use of weightlifting methods as part of training for youth sport performance appears to be increasing. Weightlifting for children and adolescents has been criticized in some circles and is a controversial aspect of resistance training for young people. Although injuries can occur during weightlifting and related activities, the incidence and rate of injury appear to be relatively low and severe injury is uncommon. A number of performance, physical, and physiological variables, such as body composition, strength, and power, are improved by weightlifting training in children, adolescents, and young athletes. Manipulating program variables, when appropriate, can have a substantial and profound influence on the psychological, physiological, physical, and performance aspects of weightlifters. An understanding of the sport, scientific training principles, and musculoskeletal growth development is necessary to properly construct a reasonable and appropriate training program. A scientific background aids in providing an evidenced basis and sound rationale in selecting appropriate methods and directing adaptations toward more specific goals and enables the coach to make choices about training and competition that might not otherwise be possible. If weightlifting training and competition are age group appropriate and are properly supervised, the sport can be substantially safe and efficacious.

Vigorous physical activity is important in maintaining a favourable health trajectory in active children: the CHAMPS Study-DK

Physical activity (PA) is critical to improving health factors such as weight, adiposity, and aerobic fitness. However, children who meet PA guideline recommendations demonstrate developmental differences in health-related outcomes. To investigate prospective associations between PA behaviour (overall PA and PA intensity) and trajectories of health-related factors among physically active children. This prospective study (2.5 years) included 391 children (baseline age: 8.1 ± 1.4 years; girls 36.3%) from ten public schools. All children performed 60-min or more of moderate-to-vigorous physical activity (MVPA) per day objectively measured. Trajectories of BMI, waist circumference, and aerobic fitness were constructed with a group-based multi-trajectory model. Three trajectory subgroups were identified: ‘high fitness/normal weight’ (48.4% of children), ‘moderate fitness /normal weight’ (42.5% of children), and ‘low fitness/overweight-obese’ (9.1% of children). Children performing higher overall PA, were less likely of being classified as members of the ‘Low Fitness/Overweight-Obese’ [Relative Risk Ratio (RRR and 95% CI) = 0.56 (0.37 to 0.85) compared to ‘high fitness/normal weight’ subgroup. Each additional 5% in light PA time was associated with approximately twofold [RRR 2.12 (1.24–3.61)] increased risk of being in the ‘low fitness/overweight-obese’ trajectory relative to the ‘high fitness/normal weight’ trajectory. Each additional 2% in vigorous-PA time was associated with a 42% and 85% reduced risk (relative to ‘high fitness/normal weight’) of being in the ‘moderate fitness/normal weight’ [RRR 0.58 (0.38–0.96)] and ‘low fitness/overweight-obesity’ [RRR 0.15 (0.06–0.37)] trajectory, respectively. Overall PA and additional time in vigorous-PA was associated with improved health-related outcomes, while light PA was negatively associated with health-related outcomes among children who adhere to PA guideline recommendations. Vigorous PA was the strongest predictor of the health trajectories. All PA guidelines for children should place greater emphasis on the importance of vigorous PA.

Fenugreek attenuates obesity-induced inflammation and improves insulin resistance through downregulation of iRhom2/TACE

AIMS

We previously reported that fenugreek-derived 4-hydroxyisoleucine ameliorates insulin resistance via regulation of TNF-α converting enzyme (TACE) expression. In the present study, we further investigate the effects and mechanisms of fenugreek on obesity-induced inflammation and insulin signaling in the high-fat diet (HFD)-challenged obese mice.

MAIN METHODS

After 12 weeks of HFD intervention, mice were treated with the low or high dosages of fenugreek. Serum levels of glucose, insulin, lipid profile, inflammation cytokines, and adipokines were detected. Macrophage infiltration and adipose tissue morphology were observed. Western blot was conducted to investigate the expressions of inactive rhomboid 2 (iRhom2) and TACE as well as other signaling pathways in subcutaneous adipose tissue.

KEY FINDINGS

We showed that fenugreek significantly suppressed body weight gain and fat accumulation in HFD-challenged obese mice. Meanwhile, fasting glucose, insulin, and HOMA-IR in fenugreek-treated mice were remarkably decreased, which were properly explained by fenugreek-induced activation of the insulin receptor signaling pathway. Moreover, the anti-inflammatory properties of fenugreek were shown by the decrease of systemic and local expressions of pro-inflammatory cytokines as well as reduced macrophage infiltration into adipose tissue. Additionally, fenugreek markedly deactivated NF-κB and JNK pathways. Finally, we demonstrated that fenugreek strikingly repressed the transcriptions and expressions of iRhom2 and TACE.

SIGNIFICANCE

Fenugreek shows an encouraging and promising property in ameliorating insulin resistance and suppressing inflammation in obesity, which might be realized by fenugreek-mediated inhibition of iRhom2/TACE axis-facilitated TNF-α release from adipocytes.

Is Muscular Fitness Associated with Future Health Benefits in Children and Adolescents? A Systematic Review and Meta-Analysis of Longitudinal Studies

BACKGROUND

No previous systematic review has quantitatively examined the association between muscular fitness during childhood and adolescence and health parameters later in life.

OBJECTIVE

The aim was to systematically review and meta-analyze the current evidence for a prospective association between muscular fitness in childhood and adolescence and future health status.

METHODS

Two authors systematically searched MEDLINE, EMBASE and SPORTDiscus electronic databases and conducted manual searching of reference lists of selected articles. Relevant articles were identified by the following criteria: apparently healthy children and adolescents aged 3-18 years with muscular fitness assessed at baseline (e.g., handgrip, standing long jump, sit-ups, among others), and a follow-up period of ≥ 1 year. The outcome measures were anthropometric and adiposity measurements and cardiometabolic, bone and musculoskeletal health parameters. Two authors independently extracted data.

RESULTS

Thirty studies were included in the meta-analysis, yielding a total of 21,686 participants. The meta-analysis found a significant, moderate-large (p < 0.05) effect size between muscular fitness at baseline and body mass index (r = - 0.14; 95% confidence interval (CI) - 0.21 to - 0.07), skinfold thickness (r = - 0.32; 95% CI - 0.40 to - 0.23), homeostasis model assessment estimated insulin resistance (r = - 0.10; 95% CI - 0.16 to - 0.05), triglycerides (r = - 0.22; 95% CI - 0.30 to - 0.13), cardiovascular disease risk score (r = - 0.29; 95% CI - 0.39 to - 0.18), and bone mineral density (r = 0.166; 95% CI 0.086 to 0.243) at follow-up.

CONCLUSION

A prospective negative association was observed between muscular fitness in childhood/adolescence and adiposity and cardiometabolic parameters in later life, together with a positive association for bone health. There is inconclusive evidence for low back pain benefits.

Prevalence of responders for hepatic fat, adiposity and liver enzyme levels in response to a lifestyle intervention in children with overweight/obesity: EFIGRO randomized controlled trial

BACKGROUND/OBJECTIVE

Exercise and lifestyle interventions have been shown to reduce hepatic fat (HF) and adiposity in youth. However, the interindividual response in HF after a lifestyle intervention with or without exercise in children is unknown. The aim of the present study was to compare interindividual variability for HF, adiposity, gamma-glutamyl transferase (GGT), and the aspartate aminotransferase to alanine aminotransferase ratio (AST/ALT) in children with overweight/obesity participating in a 22-week lifestyle intervention with (intensive intervention) or without exercise (control intervention).

METHODS

Data from 102 children (9-12 years, 55% girls) with overweight/obesity participating in the EFIGRO randomized controlled trial were analyzed. Percentage HF (magnetic resonance imaging), weight, body and fat mass index (BMI and FMI), GGT, AST/ALT, cardiorespiratory fitness (CRF, 20 meters shuttle run test) were assessed before and after the intervention by the same trained researchers. The control intervention consisted in 11 sessions of a family-based lifestyle and psycho-educational program. The intensive intervention included the control intervention plus supervised exercise (3 sessions/week).

RESULTS

The prevalence of responders for HF (54% vs. 34%), weight (27% vs. 11%), BMI (71% vs. 47%), FMI (90% vs. 60%), and GGT (69% vs. 39%) was higher in the intensive than in the control group (Ps < 0.05). Responders for weight (16 ± 3 vs. 6 ± 2 laps) and BMI (11 ± 2 vs. 3 ± 4 laps) improved more CRF levels than non-responders (Ps < 0.05).

CONCLUSIONS

The addition of exercise to a lifestyle intervention may increase the responder rates for HF, adiposity, and GGT in children with overweight/obesity. Improvements in CRF may explain differences between weight and BMI responders and non-responders.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02258126.

Effects and prevalence of responders after a multicomponent intervention on cardiometabolic risk factors in children and adolescents with overweight/obesity: Action for health study

This study aimed to verify the effect of a multicomponent intervention on cardiometabolic risk factors (CMRF), and to determine the prevalence of responders on CMRF among children and adolescents with overweight/obesity. This is a quasi-experimental study, developed with 35 children and adolescents with overweight/obesity (control group (CG) = 18; intervention group (IG) = 17), aged between 7 and 13 years. Participants in IG underwent a multicomponent intervention for 12 weeks. The following variables were evaluated: anthropometric measures, maturational stages and CMRF (body fatness, HOMA-IR, triglycerides, high-density and low-density lipoprotein) (HDL-C, LDL-C), total cholesterol (TC), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and AST/ALT ratio. Mixed analysis of variance and the prevalence of responders were used for statistical analysis. There was a significant time x group interaction on body fatness (p < 0.001), HOMA-IR (p = 0.01), HDL-C (p < 0.001), LDL-C (p = 0.009) and TC (p < 0.001). The prevalence of responders for CMRF in IG and CG was respectively: body fatness (47%; 0%; p = 0.04), HOMA-IR (58.8%; 16.6%; p = 0.04); triglycerides (17.6%; 5.5%; p = 0.31); HDL-C (76.4%; 5.5%; p = 0.01), LDL-C (35.3%; 5%; p = 0.08), TC (64.7%; 5%; p = 0.01), AST (5.8%; 0%; p = 0.87), ALT (29.4%; 11.1%; p = 0.24) and AST/ALT ratio (24.4%; 22.2%; p = 0.67). Multicomponent intervention induced positive changes on CMRF along with a higher prevalence of positive adaptations in IG than the CG in some of the cardiometabolic outcomes assessed.

Exercise and glucose control in children with insulin resistance: prevalence of non-responders

BACKGROUND

Exercise training improves cardiometabolic outcomes in 'mean terms', but little information is available in children about the impact of the frequency/week and the wide inter-individual variability to exercise training reported in adults.

OBJECTIVES

We compared the effects of resistance training (RT) and high-intensity interval training (HIT), and 'high' and 'low' frequency of training/week, for their effectiveness in decreasing insulin resistance (IR) levels in schoolchildren. A second aim was to decscribe and compare the prevalence of non-responders (NRs) between the different frequencies of training protocol.

METHODS

Fifty-three schoolchildren with IR were randomly assigned into four groups: RT at high frequency (three times/week), HIT at high frequency, RT at a low frequency (two times/week) and HIT at low frequency. The intervention lasted 6 weeks. Blood samples and body composition, blood pressure and performance measurements were taken before and after the intervention.

RESULTS

The prevalence of NRs was similar between the RTHF and HITHF (25.0% vs. 25.0%, P > 0.05) and RTLF and HITLF groups (20.0% vs. 46.6%, P = 0.174) for decreasing homeostasis model assessment of IR. However, significant differences in the prevalence of NRs were detected between RTHF and HITHF groups in fasting glucose (FGL) (18.7% vs. 58.3%, P < 0.031).

CONCLUSIONS

Both RT and HIT improves the glucose control parameters in schoolchildren over 6 weeks, but only HIT is independent of a high or low frequency of training/week. The prevalence of NRs is similar for decreasing homeostasis model assessment of IR comparing each exercise mode in high vs. low frequency/week. However, both high- and low-frequency RT and HIT results in differences in the prevalence of NRs for FGL and other cardiometabolic and performance outcomes.

Inter-individual Variability in Responses to 7 Weeks of Plyometric Jump Training in Male Youth Soccer Players

The purpose of this study was to compare the inter-individual variability in the effects of plyometric jump training (PJT) on measures of physical fitness (sprint time, change of direction speed, countermovement jump, 20- and 40-cm drop jump reactive strength index, multiple five bounds distance, maximal kicking distance, and 2.4-km time trial) in youth soccer players who completed a PJT program versus players who completed soccer training only. In a single-blinded study, participants aged between 10 and 16 years were randomly divided into a PJT group (n = 38) and a control group (n = 38). The experimental group participated in a PJT program twice weekly for 7 weeks, whereas the control group continued with their regular soccer training sessions. Between-group differences were examined using a Mann-Whitney U test. Nonresponders where defined as individuals who failed to demonstrate any beneficial change that was greater than two times the typical error of measurement from zero. The results indicated that the mean group improvement for all physical fitness measures was greater (p < 0.05) in the PJT group (Δ = 0.4 to 23.3%; ES = 0.04 to 0.58) than in the control group (Δ = 0.1 to 3.8%; ES = 0.02 to 0.35). In addition, a significantly greater (p < 0.05) number of responders across all dependent variables was observed in the PJT group (from 4 up to 33 responders) than in the control group (from 0 up to 9 responders). In conclusion, compared to soccer training only, PJT induced greater physical fitness improvements in youth soccer players, with a greater number of responders for all the physical fitness tests related to jumping, speed, change of direction speed, endurance, and kicking technical ability.

Changes in Borg scale for resistance training and test of exercise tolerance in patients undergoing allogeneic hematopoietic stem cell transplantation

PURPOSE

We aimed to investigate the relationship between Borg scale and intensity of resistance training in patients who had undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). Furthermore, the relationship between Borg scale, heart rate (HR), and intensity of exercise tolerance test was also studied.

METHODS

The study included 28 patients (19 men and 9 women) who had undergone allo-HSCT between June 2015 and February 2017. Their knee extension strengths and exercise tolerances were evaluated. Patients were asked to grade between 0 and 10 on Borg scale based on the level of difficulty experienced during exercising, after 10 repetitions in randomized 20, 40, and 60% resistance training for knee extension. Additionally, we evaluated Borg scale, HR, and load intensity during exercise tolerance test, every minute of the exercise for 2 weeks before and 3 weeks after HSCT.

RESULTS

Knee extension strength and exercise tolerance were significantly decreased 3 weeks after HSCT from those before HSCT (p < 0.01). Additionally, rise in Borg scale with increase in load intensity during knee extension resistance training, both before and after HSCT (p < 0.01), was noted. Furthermore, Borg scale was found to be associated with HR and load intensity during exercise tolerance test in patients both before and after HSCT (p < 0.01).

CONCLUSIONS

A correlation was found between Borg scale with intensity of resistance training and exercise tolerance in patients who had undergone allo-HSCT. Therefore, Borg scale could be useful to determine the intensity of physical exercise in patients who have undergone allo-HSCT.

Inhospital Exercise Training in Children With Cancer: Does It Work for All?

Purpose: Physical exercise training might counteract the weakening effects of both pediatric cancer and anti-cancer treatment. We aimed to analyze the prevalence of "responders" and "non-responders" to inhospital exercise training in children with cancer and to identify the factors that could influence responsiveness, which might help personalize exercise interventions for this patient population. Methods: We performed an ancillary analysis of the randomized controlled trial "Physical activity in Pediatric Cancer" (NCT01645436), in which 49 children with solid tumors were allocated to an inhospital exercise intervention or control group. The present study focused on the children in the former group (n = 24, 10 ± 4 years), who performed 3 weekly training sessions (aerobic + strength exercises). The intervention lasted 19 ± 8 weeks (i.e., from the start to the end of neoadjuvant chemotherapy treatment). A responder-vs-non-responder analysis was performed for physical capacity-related endpoints (five-repetition maximum strength, functional mobility tests, and cardiorespiratory fitness [CRF]). Only those participants showing improvements in a given test of a magnitude greater than both the random error and the threshold for clinically meaningful changes were considered responders. Results: Most participants improved their performance in the strength tests, with 80, 88, and 93% of total showing a positive response for seated bench press, lateral row, and leg press, respectively (p < 0.001). No significant improvements were observed for the functional mobility tests or CRF (p > 0.05, rate of responsiveness ≤ 50%). No differences between responders and non-responders were observed for sex, age, type of cancer, or treatment (i.e., including or not anthracyclines/radiotherapy). However, significant differences (p < 0.05) were observed between responders and non-responders for baseline performance in all the tests, and a significant (p < 0.05) inverse relationship was found between baseline performance and relative improvement for most endpoints. Conclusions: Although most children improved their muscle strength after the exercise intervention, a considerable individual variability was observed for the training responsiveness of functional mobility and CRF. A lower baseline performance was associated with a higher responsiveness for all the study endpoints, with the fittest children at the start of treatment showing the lowest responses. Efforts to individualize exercise prescription are needed to maximize responsiveness in pediatric cancer patients.