Strength capacity and cardiometabolic risk clustering in adolescents

Impact of the ActTeens Program on physical activity and fitness in adolescents: a cluster randomized controlled trial

BACKGROUND

The aim of our study was to evaluate the impact of the ActTeens Program on physical activity and health-related physical fitness among adolescents in Brazil.

METHODS

The "ActTeens Program" was conducted using a cluster-randomized controlled trial during 24-week school term. The sample consisted of 317 adolescents (52.7% girls; 13.61 ± 0.70 years) from four secondary schools that were randomly assigned to intervention group (N = 169) or control group (N = 148). This school-based physical activity (PA) intervention involved two components: (i) structured physical activity sessions delivered within physical education (PE) and (ii) healthy lifestyle guidance (mHealth). The primary outcome was PA assessed using Physical Activity Questionnaire for Adolescents (PAQ-A); secondary outcomes included muscular (MF) and cardiorespiratory fitness (CRF) assessed using 90-push-up, handgrip dynamometer, standing long jump, and 20 m PACER shuttle run test. Assessments were conducted at baseline, 12- and 24-week. Intervention effects were assessed using linear mixed models (LMM).

RESULTS

For the primary outcome (PA), no significant group-by-time effects were observed for physical education based-PA (0.3 score; 95%CI: -0.1; 0.6; and - 0.01 score; 95%CI: -0.03; 0.03, at 12-wk and 24-wk respectively) and total PA (-0.02 score; 95%CI: -0.2; 0.2; and - 0.01score; 95%CI: -0.2; 0.2, at 12 and 24 weeks respectively). After 24 weeks, we observed a significant group by time effects for lower body muscular fitness (12.9 cm; 95%CI, 3.2 to 22.2).

CONCLUSION

The implementation of aerobic and muscle-strengthening exercises used in the ActTeens intervention did not lead to improvements in physical activity. The intervention resulted in improved lower body muscular fitness, however, we found no significant differences for upper body muscular and cardiorespiratory fitness.

Nonalcoholic Fatty Liver Disease and Continuous Metabolic Syndrome in Adolescents with Overweight/Obesity

INTRODUCTION

Nonalcoholic fatty liver disease is the leading cause of pediatric chronic liver disease. Although nonalcoholic fatty liver disease is closely associated with obesity, its relationship with metabolic syndrome in children is not fully understood. The main aim of this study was to evaluate the association between nonalcoholic fatty liver disease and a combination of cardiometabolic risk factors in adolescents with overweight/obesity, using a pediatric metabolic syndrome score (PsiMS) to predict metabolic syndrome.

METHODS

A retrospective cohort study was conducted. Subjects with overweight/obesity aged 10 to 17 followed at two clinical centers in Portugal (2018 - 2021) were enrolled. The independent association of nonalcoholic fatty liver disease with PsiMS, and of other potential predictors, was tested through multiple regression analyses. Receiver operator characteristic curve analysis was performed to estimate the optimal cutoff of PsiMS to discriminate metabolic syndrome.

RESULTS

Eighty-four subjects were included (median age at baseline 11.5 years). The prevalence rate of nonalcoholic fatty liver disease was 51% and the prevalence rate of metabolic syndrome was 7%. The mean PsiMS was 2.05 ± 0.48 at the first evaluation, and 2.11 ± 0.52 at the last evaluation (mean follow-up time was 15 months). The nonalcoholic fatty liver disease group had significantly (p < 0.05) higher weight and body mass index z-scores, higher rate of severe obesity and higher waist circumference percentile. PsiMS was highly accurate in predicting metabolic syndrome (area under the curve = 0.96), with an optimal cutoff of 2.46 (sensitivity 100%, specificity 89%). In the univariate analysis, no statistically significant association was observed between nonalcoholic fatty liver disease and PsiMS. In the multiple regression analysis, female sex had a negative association with PsiMS (first and last evaluation). Independent predictors of a higher PsiMS at first evaluation were: ≥ 2 metabolic syndrome criteria, body mass index z-score, insulin resistance and dyslipidemia. At the last evaluation, independent predictors of a higher PsiMS were: nonalcoholic fatty liver disease, baseline PsiMS and body mass index increase from baseline.

CONCLUSION

The results suggest a good performance of the PsiMS to assess metabolic syndrome and that nonalcoholic fatty liver disease is associated with PsiMS at follow-up.

Role of muscle mass in the association between handgrip strength and blood pressure in children and adolescents

Studies have reported conflicting results on the association between handgrip strength (HGS) and blood pressure during childhood and adolescence. High multicollinearity involving somatic components that influence both HGS and blood pressure might be an important source of bias. This study sought to investigate the independent effects of HGS and muscle mass on blood pressure levels in children and adolescents. Muscle mass and fat mass (Multifrequency Electrical Bioimpedance) and systolic (SBP) and diastolic (DBP) blood pressure (Automatic oscillometric device) were assessed in 833 volunteers aged 6-18 years, of both sexes. Handgrip strength-for-age quartiles were calculated and participants were assigned to groups by HGS quartiles. Analysis of covariance was conducted to address the linear association between HGS and SBP adjusted for height, muscle mass, and fat mass. To test for linear trend, contrast analysis was conducted. Partial eta-squared was used to confirm or rule out a small significant effect of the independent variables on SBP. The effect size of HGS on SBP was not significant in both sexes. In girls, 1.7% of the between-groups variance in SBP was accounted for by muscle mass (P = 0.016). In boys, 2.3% and 1.8% of the between-groups variance in SBP was accounted for by muscle mass (P = 0.001) and height (P = 0.005), respectively. In conclusion, children with a more advanced physical maturity for their age, that is, who are taller, stronger, and have greater fat-free mass, may be nearly reaching the physiological parameters of adulthood, and consequently have higher systolic blood pressure.

Lifelong Fitness in Ambulatory Children and Adolescents with Cerebral Palsy I: Key Ingredients for Bone and Muscle Health

Physical activity of a sufficient amount and intensity is essential to health and the prevention of a sedentary lifestyle in all children as they transition into adolescence and adulthood. While fostering a fit lifestyle in all children can be challenging, it may be even more so for those with cerebral palsy (CP). Evidence suggests that bone and muscle health can improve with targeted exercise programs for children with CP. Yet, it is not clear how musculoskeletal improvements are sustained into adulthood. In this perspective, we introduce key ingredients and guidelines to promote bone and muscle health in ambulatory children with CP (GMFCS I-III), which could lay the foundation for sustained fitness and musculoskeletal health as they transition from childhood to adolescence and adulthood. First, one must consider crucial characteristics of the skeletal and muscular systems as well as key factors to augment bone and muscle integrity. Second, to build a better foundation, we must consider critical time periods and essential ingredients for programming. Finally, to foster the sustainability of a fit lifestyle, we must encourage commitment and self-initiated action while ensuring the attainment of skill acquisition and function. Thus, the overall objective of this perspective paper is to guide exercise programming and community implementation to truly alter lifelong fitness in persons with CP.

Physical fitness of primary school children differs depending on their timing of school enrollment

Previous research has shown that children who were enrolled to school according to the legal key date (i.e., keyage children, between eight and nine years in third grade) exhibited a linear physical fitness development in the ninth year of life. In contrast, children who were enrolled with a delay (i.e., older-than-keyage children [OTK], between nine and ten years in third grade) exhibited a lower physical fitness compared to what would be expected for their age. In these studies, cross-sectional age differences within third grade and timing of school enrollment were confounded. The present study investigated the longitudinal development of keyage and OTK children from third to fifth grade. This design also afforded a comparison of the two groups at the same average chronological age, that is a dissociation of the effects of timing of school enrollment and age. We tested six physical fitness components: cardiorespiratory endurance, coordination, speed, power of lower and upper limbs, and static balance. 1502 children (i.e., 1206 keyage and 296 OTK children) from 35 schools were tested in third, fourth, and fifth grade. Except for cardiorespiratory endurance, both groups developed from third to fourth and from fourth to fifth grade and keyage children outperformed OTK children at the average ages of 9.5 or 10.5 years. For cardiorespiratory endurance, there was no significant gain from fourth to fifth grade and keyage and OTK children did not differ significantly at 10.5 years of age. One reason for a delayed school enrollment could be that a child is (or is perceived as) biologically younger than their chronological age at the school entry examination, implying a negative correlation between chronological and biological age for OTK children. Indeed, a simple reflection of chronological age brought the developmental rate of the chronologically youngest OTK children in line with the developmental rate observed for keyage children, but did not eliminate all differences. The mapping of chronological and biological age of OTK children and other possible reasons for lower physical fitness of OTK children remain a task for future research.

Association of handgrip strength with anthropometry of a Brazilian healthy adolescent sample

The importance of dynamometric and anthropometric information for industry is known; however, few studies have investigated the relationship between anthropometry and handgrip strength (HGS) in adolescents. The aim of the present study was to investigate the association of anthropometric variables with the level of HGS production in adolescents. Participants were 541 adolescents aged 12-16 years from a public school in the city of Rio de Janeiro. The behavior of the following variables was examined: the ability to generate HGS, age, total body mass, height and hand dimensions (hand width, hand span, hand length). The results showed an increase in the ability to generate HGS in adolescence and a significant difference between the genders from 13 years old, where boys generated higher HGS values. Correlations between HGS and total body mass and the hand width stood out in both genders, indicating a greater association.

Body Fat Is Superior to Body Mass Index in Predicting Cardiometabolic Risk Factors in Adolescents

BACKGROUND

Excess adiposity is one of the main risk factors for the development of cardiovascular and metabolic diseases. The purpose of this study is to compare cardiometabolic risk factors in eutrophic adolescents with a high body fat percentage (%BF) with eutrophic adolescents with adequate %BF and those with excess weight and %BF.

METHODS

Cross-sectional study with 1043 adolescents. This study presented power equal to 99.75%. Body fat and anthropometric, clinical and biochemical indicators were evaluated. Participants were grouped according to body composition classified by body mass index (BMI) and body fat percentage. Statistical analyses were performed using R software version 4.0.2, adopting a significance level of 5%. The Mann-Whitney test, principal components analysis and logistic regression were performed.

RESULTS

It was observed that the SG was more similar to GC2 than to GC1 for both sexes, demonstrating that there was a greater similarity between these groups in relation to the evaluated factors. Higher values for TC, SBP and TG were associated with the SG when the CG1 was used as reference, controlled for sex and age. Likewise, higher TC values and lower levels of SBP, TG and LDL were related to SG when the CG2 was used as reference.

CONCLUSION

Body fat assessment is more effective in predicting risk factors and cardiometabolic diseases than BMI alone.

Differential Relationship of Grip Strength with Body Composition and Lifestyle Factors Between Indian Urban and Rural Boys and Girls

OBJECTIVES

To assess grip strength and gender differences in grip strength in 9-18-y-old urban and rural Indian children, to study association of grip strength with body composition, and assess determinants of grip strength.

METHODS

This was part of a multicenter, cross-sectional, school-based study (n = 1978, mean age 13.3 ± 2.2 y) from three urban and rural states. Anthropometry, body composition, dietary intake, physical activity, sunlight exposure, and grip strength (in kg) were measured.

RESULTS

Mean grip strength increased with age but plateaued in girls after 12 y and was higher in boys (19.6 ± 9.2) than girls (14.3 ± 5.3) (p < 0.05). Mean grip strength was higher in urban (21.05 ± 9.7) than in rural boys (17.8 ± 8.2) (p < 0.05), and comparable in urban (14.9 ± 5.2) and rural girls (13.8 ± 5.5). Grip strength in girls remained lower than boys after adjusting for muscle mass. Difference between boys and girls reduced after body size [body mass index (BMI)] correction, but remained low in girls, plateauing after 15 y. Muscle mass and age were significant determinants of grip strength in all children. On addition of lifestyle factors to the model, grip strength was explained to varied degrees in the children.

CONCLUSION

In boys, nutrition through body size and composition was largely responsible for the differences in grip strength, and in girls, additionally, sociocultural factors also possibly impacted grip strength.

Exposure to mixture of heavy metals and muscle strength in children and adolescents: a population-based study

Human beings are exposed to heavy metals through various ways in daily life. However, the effect of heavy metal mixtures on muscle strength in children and adolescents remains unclear. We aimed to investigate the relationship of exposure to heavy metal mixtures (barium, cadmium, cobalt, manganese, molybdenum, lead, antimony, strontium, tin, thallium, tungsten, uranium, and cesium) with muscle strength in children and adolescents. A total of 1357 (boys, 50.8%) participants aged between 8 and 17 were extracted from the National Health and Nutrition Examination Surveys 2011-2014. Urine metals were measured by inductively coupled plasma-mass spectrometry. Muscle strength was measured through a grip test using a handgrip dynamometer. Weighted quantile sum regression was performed to estimate the mixture effect of urinary metals on muscle strength. After adjusting for potential confounders, comparing participants in the highest versus lowest quartiles of cobalt, molybdenum, lead, antimony, strontium, thallium, and cesium, the handgrip strength decreased by - 4.48 kg (95% CI: - 6.93, - 2.03), - 6.13 kg (- 8.76, - 3.51), - 2.26 kg (- 4.22, - 0.30), - 2.38 kg (- 4.68, - 0.08), - 2.29 kg (- 4.45, - 0.13), - 4.78 kg (- 7.13, - 2.44), and - 5.68 kg (- 9.20, - 2.17), respectively. Furthermore, exposure to a mixture of metals were also significantly associated with decreased muscle strength (β: - 2.62 kg; 95% CI: - 3.71, - 1.54). Findings from the present study suggest that higher heavy metal exposure and the exposure levels of a mixture of metals in urine are inversely related to handgrip strength, implying that children's grip strength is not entirely explained by energy intake or lack of exercise, but may be related to environmental pollutants.

Is grip strength linked to body composition and cardiovascular risk markers in primary schoolchildren? Cross-sectional data from three African countries

OBJECTIVES

Muscular strength represents a specific component of health-related fitness. Hand grip strength (HGS) is used as an indicator for musculoskeletal fitness in children. HGS can also be used as a marker of cardiometabolic risk, but most available HGS data are derived from Western high-income countries. Therefore, this study examines whether HGS is associated with body composition and markers of cardiovascular risk in children from three sub-Saharan African countries.

DESIGN

Cross-sectional study.

SETTING

Public primary schools (grade 1-4) in Taabo (Côte d'Ivoire), Gqeberha (South Africa) and Ifakara (Tanzania).

PARTICIPANTS

Data from 467 children from Côte d'Ivoire (210 boys, 257 girls), 864 children from South Africa (429 boys, 435 girls) and 695 children from Tanzania (334 boys, 361 girls) were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

Body composition (assessed via bioelectrical impedance analysis) was the primary outcome. Cardiovascular risk markers were considered as secondary outcome. Blood pressure was measured with an oscillometric monitor, and blood markers (cholesterol, triglycerides, glycated haemoglobin) via Afinion point-of-care testing. HGS (independent variable) was assessed with a hydraulic hand dynamometer. Inferential statistics are based on mixed linear regressions and analyses of covariance.

RESULTS

Across all study sites, higher HGS was associated with lower body fat, higher muscle mass and higher fat-free mass (p<0.001, 3.9%-10.0% explained variance), both in boys and girls. No consistent association was found between HGS and cardiovascular risk markers.

CONCLUSIONS

HGS assessment is popular due to its simplicity, feasibility, practical utility and high reliability of measurements. This is one of the first HGS studies with children from sub-Saharan Africa. There is a great need for further studies to examine whether our findings can be replicated, to develop reference values for African children, to establish links to other health outcomes, and to explore whether HGS is associated with later development of cardiovascular risk markers.

TRIAL REGISTRATION NUMBER

ISRCTN29534081.

Muscular Fitness and Cardiometabolic Variables in Children and Adolescents: A Systematic Review

BACKGROUND

The importance of muscular fitness (MF) in the performance of activities of daily living is unequivocal. Additionally, emerging evidence has shown MF can reduce cardiometabolic risk in children and adolescents.

OBJECTIVES

The purpose of this study was to examine and summarize the evidence regarding the relationship between MF phenotypes (i.e., maximum muscular strength/power, muscular endurance, and maximum muscular strength/power/endurance) and cardiometabolic variables (obesity, blood pressure, lipids, glucose homeostasis, inflammatory markers, and clustered cardiometabolic variables) in children and adolescents.

DESIGN

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and was registered with PROSPERO, number CRD42020179273.

DATA SOURCES

A systematic review was performed on five databases (PubMed, EMBASE, SciELO, Scopus, and Web of Knowledge) from database inception to May 2020, with complementary searches in reference lists.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Eligibility criteria included (1) a study sample of youth aged ≤ 19 years, (2) an assessment of MF with individual or clustered cardiometabolic variables derived from adjusted models (regardless of test/measurement adopted or direction of reported association), and (3) a report of the association between both, using observational studies. Only original articles published in peer-reviewed journals in English, Portuguese, and Spanish languages were considered. The quality of the included studies was assessed by using the National Heart, Lung, and Blood Institute checklist. The percentage of results reporting a statistically significant inverse association between each MF phenotype and cardiometabolic variables was calculated.

RESULTS

Of the 23,686 articles initially identified, 96 were included (77 cross-sectional and 19 longitudinal), with data from children and adolescents from 35 countries. The score for the quality of evidence ranged from 0.33 to 0.92 (1.00 maximum). MF assessed by maximum muscular strength/power was inversely associated with lower obesity (64/113 total results (56.6%)) and reduction in clustered cardiometabolic risk (28/48 total results (58.3%)). When assessed by muscular endurance, an inverse association with obesity (30/44 total results (68.1%)) and cardiometabolic risk (5/8 total results (62.5%)) was identified. Most of the results for the relationship between MF phenotypes with blood pressure, lipids, glucose homeostasis, and inflammatory markers indicated a paucity of evidence for these interrelationships (percentage of results below 50.0%).

CONCLUSION

MF assessed by maximum muscular strength/power or muscular endurance is potentially associated with lower obesity and lower risk related to clustered cardiometabolic variables in children and adolescents. There is limited support for an inverse association between MF with blood pressure, lipids, glucose homeostasis biomarkers, and inflammatory markers in children and adolescents.

Overweight/Obese Schoolchildren with Low Muscle Strength Have a Lower Cardiorespiratory Capacity and Greater Cardiovascular Risk: Results of the School Health Survey of the Extreme South of Chile 2019

Objective: To compare cardiovascular risk and cardiorespiratory capacity in schoolchildren from a region in the extreme south of Chile according to nutritional status and muscular strength. Methods: An analytical cross-sectional study was performed on a sample of 594 schoolchildren from 5th to 8th grade in the extreme south of Chile. Based on body mass index and lower limb muscle strength, participants were divided into four groups: high strength-normal weight, high strength-overweight/obese, low strength-normal weight, and low strength-overweight/obese. Then, waist-to-height ratio and cardiorespiratory capacity, measured with the 20 m shuttle run test, were assessed to determine their cardiovascular risk, comparing the four groups. Results: The overweight/obese group with high muscular strength presented better indicators in anthropometric variables (waist circumference and waist-to-height ratio) than their peers with low muscular strength. Additionally, the overweight/obese group with low muscular strength presented a lower cardiorespiratory capacity than their peers with high muscular strength. Both results were observed in boys and girls. Conclusion: The results of this study suggest that overweight/obese schoolchildren with high muscle strength present healthier anthropometric indicators and greater cardiorespiratory capacity than their peers with low muscle strength. These results confirm the relevance of measuring muscle strength in schoolchildren and its usefulness to assess functionality. These results encourage the scientific community to continue studying the role that muscle strength plays in modulating the effects of overweight and obesity on respiratory and cardiovascular conditions in childhood.

Plasma Concentrations of Per- and Polyfluoroalkyl Substances and Body Composition From Mid-Childhood to Early Adolescence

CONTEXT

Per- and polyfluoroalkyl substances (PFAS) may alter body composition by lowering anabolic hormones and increasing inflammation, but data are limited, particularly in adolescence when body composition is rapidly changing.

OBJECTIVE

To evaluate associations of PFAS plasma concentrations in childhood with change in body composition through early adolescence.

METHODS

A total of 537 children in the Boston-area Project Viva cohort participated in this study. We used multivariable linear regression and Bayesian kernel machine regression (BKMR) to examine associations of plasma concentrations of 6 PFAS, quantified by mass spectrometry, in mid-childhood (mean age, 7.9 years; 2007-2010) with change in body composition measured by dual-energy x-ray absorptiometry from mid-childhood to early adolescence (mean age, 13.1 years).

RESULTS

In single-PFAS linear regression models, children with higher concentrations of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorodecanoate (PFDA), and perfluorohexane sulfonate (PFHxS) had less accrual of lean mass (eg, -0.33 [95% CI: -0.52, -0.13] kg/m2 per doubling of PFOA). Children with higher PFOS and PFHxS had less accrual of total and truncal fat mass (eg, -0.32 [95% CI: -0.54, -0.11] kg/m2 total fat mass per doubling of PFOS), particularly subcutaneous fat mass (eg, -17.26 [95% CI -32.25, -2.27] g/m2 per doubling of PFOS). Children with higher PFDA and perfluorononanoate (PFNA) had greater accrual of visceral fat mass (eg, 0.44 [95% CI: 0.13, 0.75] g/m2 per doubling of PFDA). Results from BKMR mixture models were consistent with linear regression analyses.

CONCLUSION

Early life exposure to some but not all PFAS may be associated with adverse changes in body composition.

Plasma Concentrations of Per- and Polyfluoroalkyl Substances and Body Composition From Mid-Childhood to Early Adolescence

CONTEXT

Per- and polyfluoroalkyl substances (PFAS) may alter body composition by lowering anabolic hormones and increasing inflammation, but data are limited, particularly in adolescence when body composition is rapidly changing.

OBJECTIVE

To evaluate associations of PFAS plasma concentrations in childhood with change in body composition through early adolescence.

METHODS

A total of 537 children in the Boston-area Project Viva cohort participated in this study. We used multivariable linear regression and Bayesian kernel machine regression (BKMR) to examine associations of plasma concentrations of 6 PFAS, quantified by mass spectrometry, in mid-childhood (mean age, 7.9 years; 2007-2010) with change in body composition measured by dual-energy x-ray absorptiometry from mid-childhood to early adolescence (mean age, 13.1 years).

RESULTS

In single-PFAS linear regression models, children with higher concentrations of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorodecanoate (PFDA), and perfluorohexane sulfonate (PFHxS) had less accrual of lean mass (eg, -0.33 [95% CI: -0.52, -0.13] kg/m2 per doubling of PFOA). Children with higher PFOS and PFHxS had less accrual of total and truncal fat mass (eg, -0.32 [95% CI: -0.54, -0.11] kg/m2 total fat mass per doubling of PFOS), particularly subcutaneous fat mass (eg, -17.26 [95% CI -32.25, -2.27] g/m2 per doubling of PFOS). Children with higher PFDA and perfluorononanoate (PFNA) had greater accrual of visceral fat mass (eg, 0.44 [95% CI: 0.13, 0.75] g/m2 per doubling of PFDA). Results from BKMR mixture models were consistent with linear regression analyses.

CONCLUSION

Early life exposure to some but not all PFAS may be associated with adverse changes in body composition.

Normative data for handgrip strength in Iranian healthy children and adolescents aged 7-18 years: comparison with international norms

BACKGROUND

Grip strength is an essential component of physical fitness. The objective of this study was to develop normative handgrip strength data for Iranian healthy boys and girls comparing their handgrip strength with international reference values.

METHODS

Handgrip strength was measured in 2637 healthy children/adolescents (1391 boys and 1246 girls), aged 7-18 years, using a standard adjustable Jamar hand dynamometer (Model 5030 J1, Sammons Preston Rolyan, Bolingbrook, IL, USA). Body mass (kg) and stature (cm) were measured and body mass index was computed in kg/m2. The sample was stratified by gender, age, and hand preference.

RESULTS

Handgrip strength increased with age and was considerably higher in boys than in girls for all age groups (p < 0.001). Grip strength had a parallel and linear growth for both genders until the age of about 11 years and showed a steeper upward slope in boys than in girls thereafter. The findings of the current investigation were significantly different from those of the previously published normative data, especially for boys over the age of 12 years and girls in the age range of 7-18 years (p < 0.001). This difference was mainly in such a way that the Iranians had lower handgrip strength.

CONCLUSIONS

The differences between present results and those of similar available in the literature in this field emphasize the significant role of using normative data specific to a particular population in research or clinical settings.

Low Muscular Strength, Weight Status, and Metabolic Syndrome in Adolescents: National Health and Nutrition Examination Survey 2011-2014

PURPOSE

To investigate the association between muscular strength and metabolic syndrome (MetS), with a specific focus on the role of weight status, using a nationally representative sample of US youth.

METHODS

The analysis included 409 boys and 415 girls from the 2011 to 2014 National Health and Nutrition Examination Survey between 12 and 18 years of age. The prevalence of MetS was defined using age- and sex-specific criteria for abdominal obesity, elevated triglycerides, blood pressure, fasting glucose, and low high-density lipoprotein (HDL) cholesterol. Strength was assessed via handgrip dynamometer and expressed as age- and sex-specific z scores of relative strength. Low strength was defined as a relative strength below the 25th percentile. Analyses controlled for age, sex, race/ethnicity, physical activity, and weight status.

RESULTS

The sample prevalence of MetS was approximately 5.3%. However, MetS prevalence was 18.5% in overweight/obese youth with low strength. The adjusted odds of MetS were 3.1 (95% confidence interval, 1.5-6.3, P < .001) times higher for overweight/obese youth with low strength versus sufficient strength.

CONCLUSION

Muscular strength is predictive of adolescent MetS, specifically in those with unhealthy weight status. Approximately one in 5 overweight/obese youth with low strength had MetS. These findings highlight the relevance of muscular strength in youth cardiometabolic morbidities.

Association between muscle strength and risk factors for metabolic syndrome in children and adolescents: a systematic review

The aim of this systematic review was to identify and summarize evidence for the association between muscle strength (MS) and metabolic syndrome (MetS), and MS and combinations of risk factors for MetS in children and adolescents. Five databases (Medline/PubMed, EBSCO, Scielo, Scopus, and Web of Knowledge) were searched up to November 2019 with complementary reference list searches. Inclusion criteria were studies that investigated the relationship between MS and MetS or MS and combinations of risk factors for MetS in children and adolescents (≤19 years of age). Risk of bias was assessed using standard procedures. From the total of 15,599 articles initially identified, 13 articles were included, representing 11,641 children and adolescents. Higher MS values were associated with lower risk for MetS or combinations of risk factors for MetS (n=11/13 studies). Of the total of included studies, about 23.1% (03/13) were longitudinal and all included studies were classified as having a moderate risk of bias. This review provides preliminary evidence for a beneficial relationship between MS and MetS among children and adolescents. Additionally, although the body of evidence points to the beneficial relationship between higher MS and lower risk for combination of factors for MetS in children and adolescents, this relationship is inconclusive.

Analysis of hand-forearm anthropometric components in assessing handgrip and pinch strengths of school-aged children and adolescents: a partial least squares (PLS) approach

Background

The purpose of this study was to examine the influence of hand-forearm anthropometric dimensions on handgrip and pinch strengths among 7–18 years children and adolescents and to investigate the extent to which these variables can be used to predict hand strength.

Methods

Four types of hand strengths including handgrip, tip to tip, key, and three-jaw chuck pinches were measured in 2637 healthy children and adolescents (1391 boys and 1246 girls) aged 7–18 years using standard adjustable Jamar hydraulic hand dynamometer and pinch gauge. A set of 17 hand-forearm anthropometric dimensions were also measured with an accurate digital caliper and tape measure.

Results

No significant differences were found between the hand strengths of boys and girls up to the age of 10 years. Gender related differences in handgrip and pinches were observed from the age of 11 years onwards, with boys always being stronger. The dominant hand was stronger than the non-dominant hand (8% for handgrip and by about 10% for all three types of pinches). The strongest correlations were found between the hand length and hand strengths (r > 0.83 for handgrip and three all pinches; p < 0.001, 2-tailed). Based on the partial least squares (PLS) analysis, 8 out of 17 anthropometric indices including hand length, hand circumference, thumb length, index finger length, middle finger length, and forearm length had considerable loadings in the PLS analysis, which together accounted for 46% of the total variance.

Conclusions

These results may be used by health professionals in clinical settings as well as by designers to create ergonomic hand tools.

Vitamin D status is associated with muscular strength in a nationally representative sample of US youth

AIM

To evaluate the association between serum 25-hydroxyvitamin D (25OHD) and muscular strength in a nationally representative sample of US youth.

METHODS

Participants (n = 3350) were 6- to 18-y-olds from 2011 to 2014 National Health and Nutrition Examination Survey. Relative handgrip strength was quantified using age- and sex-specific z-scores. Poor strength was defined as those <25th percentile. Multivariate general linear and logistic models were used to compare strength and poor strength status by clinically relevant groupings of 25OHD.

RESULTS

Approximately 20.2% of youth had 25OHD <50 nmol/L. Mean relative strength was highest for those at ≥75 nmol/L of 25OHD. The percentage of boys/girls with poor strength in the <50 nmol/L, 50-74.9 nmol/L and ≥75 nmol/L groups was 34.9%/32.3%, 25.8%/28.2% and 14.0%/15.8%, respectively. The odds of boys and girls with <50 nmol/L 25OHD having poor strength were 2.8 (95% CI: 1.4, 5.5) and 3.4 (1.7, 6.8) times higher compared to those with ≥75 nmol/L, respectively.

CONCLUSION

Higher levels of circulating vitamin D were associated with higher relative strength, and poor strength was more prevalent when 25OHD was <75 nmol/L. These findings highlight the value of vitamin D for the muscle-bone unit and potential extraskeletal ramifications.

Relationship of Handgrip Strength to Metabolic Syndrome Among Korean Adolescents 10-18 Years of Age: Results from the Korean National Health and Nutrition Examination Survey 2014-18

Introduction: Handgrip strength (HGS), a simple, convenient, and economic measurement of muscle strength, is known to be related to metabolic syndrome (MetS) in adults. This relationship in adolescents, however, has not been widely examined. this study investigated the relationship of MetS (as defined by the International Diabetes Federation [IDF]'s criteria) to HGS in Korean adolescents. Materials and Methods: This cross-sectional study analyzed data on 2802 adolescents 10-18 years of age from the Korean National Health and Nutrition Examination Survey (KNHANES) 2014-18, which had measured and recorded HGS, body mass index, and other parameters relevant to MetS. Normalized HGS was defined as the sum of the maximum HGS from both hands normalized per weight. Complex sample multivariate logistic regression analyses were performed to investigate the relationship between HGS and MetS. Results: The risk of MetS decreased with increasing sex-specific quartile of normalized HGS in both boys and girls after adjustment for age (P_trend < 0.001). Higher HGS was associated with lower odds of having MetS, such that for every 5% increase of normalized HGS, the odds were decreased by factors of 0.79 (0.73-0.85) and 0.67 (0.59-0.77) for boys and girls, respectively, after age adjustment. Conclusions: This population-based, nationally representative study suggests that higher HGS is associated with lower risk of MetS in Korean adolescents regardless of sex.

The Association of Grip Strength, Body Mass Index, and Lung Function in Youth with Cystic Fibrosis

Compared with body mass index (BMI), lean body mass and fat-free mass are strongly associated with lung function in children and adolescents with cystic fibrosis (CF). Methods of measuring body composition in youth with CF are often unreliable, expensive, or not clinically feasible. Grip strength (GS), a measure of muscle function, is used as a surrogate for muscle mass and is an indicator of nutrition status. This quality improvement project explored the feasibility of measuring GS in medically stable youth with CF, aged 6-21 years. A total 361 GS measurements were performed by using a digital hand dynamometer in youth from a single CF center. Using reference tables that were created for this project by merging data from the 2011-2012 and 2013-2014 National Health and Nutrition Examination Surveys, youth with CF were found to be weaker than age- and gender-matched peers, even when controlled for differences in size. A positive association (P < .001) was found between GS percentile and lung function, as measured by forced expiratory volume in 1 second percent predicted (FEV1pp). Statistical analysis revealed that both BMI percentile and absolute GS (AGS) percentile were positively associated with FEV1pp and with each other, primarily at the lower levels of BMI percentile (<50%) and AGS percentile (<50%). GS may provide a reliable, less expensive, and clinically feasible alternative to body composition measurements in monitoring nutrition status in youth with CF, especially in youth whose BMI is in the <50th percentile.

Association between Dietary Patterns and Handgrip Strength: Analysis of the Korean National Health and Nutrition Examination Survey Data Between 2014 and 2017

Non-invasive anthropometric measurement methods such as those for measuring height and weight are crucial in pediatric patients. However, research focusing on the association between the type of dietary pattern and handgrip strength and handgrip-to-weight ratio in adolescents has not been carried out yet. This cross-sectional analysis of the 2014–2017 Korean National Health and Nutrition Examination Survey assessed 2327 adolescents (aged 10–18 years) who had their handgrip strength measured and analyzed its association with dietary pattern. The clusters were examined for nutritional values, and the ready-to-eat, balanced, and Western-style fast-food clusters were ultimately generated. Overall, 85.6% of the participants were assigned to a ready-to-eat dietary pattern, 9.3% to a Western-style fast-food dietary pattern, and 5.1% to a balanced dietary pattern. Compared with the participants following a balanced dietary pattern, those following a ready-to-eat dietary pattern were shown to have a significantly lower handgrip strength and handgrip-to-weight ratio. Decreased handgrip strength and handgrip-to-weight ratio values in participants following ready-to-eat dietary patterns indicate a diffuse problem in adolescents’ health and possibly imply an association between reduced muscle quality and dietary pattern. Therefore, the overall environmental factors potentially inducing such unhealthy dietary preferences should be investigated, and appropriate lifestyle changes in Korean adolescents should be encouraged.

Association between handgrip strength and cardiovascular risk factors among Korean adolescents

Background It remains unclear whether muscle strength, which reduces cardiovascular (CV) risk in adults, is associated with similar protection in Asian adolescents. This study investigated the association between handgrip strength and CV health in a large Korean sample of school-age adolescents. Methods We performed a cross-sectional analysis of adolescents aged 10-18 years (n=4,018) from the Korean National Health and Nutrition Survey between 2014 and 2017. Handgrip strength was measured using a dynamometer. CV risk factors include waist circumference, blood pressure, fasting glucose or hemoglobin A1c, and lipid levels. Logistic regression models were applied with adjustment for potential confounders. Results The mean age of participants was 14.0 years, and 53.6% were boys. Mean handgrip strength was 30.4 kg for boys and 22.0 kg for girls. Boys more frequently had high systolic blood pressure and impaired fasting glucose, whereas girls more frequently had low high-density lipoprotein cholesterol. Multivariate logistic regression analysis revealed that in boys only, handgrip strength was negatively associated with central obesity and hypertriglyceridemia and positively associated with higher systolic blood pressure. Conclusion Handgrip strength is independently associated with some CV risk factors only in boys.

Health-related physical fitness indicators and clustered cardiometabolic risk factors in adolescents: A longitudinal study

Background/Objective

This study examined relationships between health-related physical fitness indicators and clustered cardiometabolic risk factors in adolescents between 2014 and 2017.

Methods

The sample consisted of 93 students (60% girls), with complete data sets in both 2014 and 2017. The physical fitness components evaluated were: flexibility (sit and reach), muscular fitness (curl-up and push-up), cardiorespiratory fitness (progressive aerobic cardiovascular endurance run), and body fat (BMI). The cardiometabolic risk factors were: waist circumference, blood pressure, high-density lipoprotein cholesterol (HDL-C), triglycerides and fasting blood glucose. Z-scores were calculated for each risk factor, with the sum of risk factor z-scores values used to represent clustered cardiometabolic risk.

Results

The results of cross-sectional analysis indicated that muscle fitness (curl-up: β = −0.37, p < 0.001; push-up: β = −0.38, p < 0.005) and cardiorespiratory fitness (β = −0.56, p < 0.001) were inversely associated with clustered cardiometabolic risk, with BMI positively associated (β = 0.58, p < 0.001). In the longitudinal analysis, cardiorespiratory fitness (β = −0.33; p < 0.005) and body fat (β = 0.46, p < 0.001) demonstrated a significant association with clustered cardiometabolic risk. However, no significant associations between the health-related physical fitness and clustered cardiometabolic risk were observed after adjustment for baseline values.

Conclusion

Our cross-sectional findings highlight the importance of health-related physical fitness indicators to adolescents. In regarding the longitudinal analysis, further studies are needed in order to clarify the influence of physical fitness in the adolescence and cardiometabolic risk later in life.

Grip Strength Cut Points for Diabetes Risk Among Apparently Healthy U.S. Adults

INTRODUCTION

Early detection screening tools are needed to aid in preventing vascular complications associated with type 2 diabetes. As low muscular strength is linked to increased diabetes risk, the purpose of this study is to establish muscular strength cut points for determining diabetes risk using a large, nationally representative U.S.

METHODS

Using the 2011-2012 and 2013-2014 National Health and Nutrition Examination Survey data, 5,108 participants aged 20-80 years (68.6% aged 20-50 years; young male participants, n=1,813, mean age=33.43 years; young female participants, n=1,692, mean age=33.39 years; older male participants, n=813, mean age=59.92 years; older female participants, n=790, mean age=60.45 years) and free of common diabetes comorbidities were included. Muscular strength was assessed using a handgrip dynamometer and normalized by adjusting for body weight. A logistic regression for survey data controlling for covariates was used to determine normalized grip strength cut points. Diabetes risk was determined using American Diabetes Association diagnostic criteria. Analyses were conducted in the summer of 2019.

RESULTS

Normalized grip strength significantly predicted diabetes (p=0.0332), and the cut points for detecting diabetes risk included 0.78 (young male participants), 0.57 (young female participants), 0.68 (older male participants), and 0.49 (older female participants). The risk percentages for diabetes and estimated rates reported for all subgroups were comparable, and the risk percentages included 6.84 (95% CI=5.32, 8.36; younger male participants), 7.49 (95% CI=5.87, 9.10; younger female participants), 5.76 (95% CI=2.34, 9.19, older male participants), and 4.27 (95% CI=2.44, 6.10; older female participants).

CONCLUSIONS

Normalized grip strength using the cut points proposed in this paper may be a useful screening tool for diabetes risk in apparently healthy, normotensive adults.

Resistance Training for Older Adults: Position Statement From the National Strength and Conditioning Association

Fragala, MS, Cadore, EL, Dorgo, S, Izquierdo, M, Kraemer, WJ, Peterson, MD, and Ryan, ED. Resistance training for older adults: position statement from the national strength and conditioning association. J Strength Cond Res 33(8): 2019-2052, 2019-Aging, even in the absence of chronic disease, is associated with a variety of biological changes that can contribute to decreases in skeletal muscle mass, strength, and function. Such losses decrease physiologic resilience and increase vulnerability to catastrophic events. As such, strategies for both prevention and treatment are necessary for the health and well-being of older adults. The purpose of this Position Statement is to provide an overview of the current and relevant literature and provide evidence-based recommendations for resistance training for older adults. As presented in this Position Statement, current research has demonstrated that countering muscle disuse through resistance training is a powerful intervention to combat the loss of muscle strength and muscle mass, physiological vulnerability, and their debilitating consequences on physical functioning, mobility, independence, chronic disease management, psychological well-being, quality of life, and healthy life expectancy. This Position Statement provides evidence to support recommendations for successful resistance training in older adults related to 4 parts: (a) program design variables, (b) physiological adaptations, (c) functional benefits, and (d) considerations for frailty, sarcopenia, and other chronic conditions. The goal of this Position Statement is to a) help foster a more unified and holistic approach to resistance training for older adults, b) promote the health and functional benefits of resistance training for older adults, and c) prevent or minimize fears and other barriers to implementation of resistance training programs for older adults.

Increased body fat and reduced insulin sensitivity are associated with impaired endothelial function and subendocardial viability in healthy, non-Hispanic white adolescents

BACKGROUND

Cardiovascular disease has its origins in adolescents. Endothelial dysfunction, arterial stiffness, and decreased endocardial oxygen supply: demand ratios are early functional markers of cardiovascular risk. The goal of this study was to determine the relationships of these markers to physical, inflammatory, and metabolic markers in healthy non-Hispanic, white adolescents.

METHODS

Thirty-four of the 75 subjects were female. Mean age was 15.0 ± 1.7 years and mean body mass index (BMI) was 22.0 ± 5.8 kg/m² (mean ± SD). Reactive hyperemia was measured using venous occlusion plethysmography. Arterial tonometry was used to measure the augmentation index (AIx₇₅ ) and the Buckberg subendocardial viability ratio. Blood samples were taken to measure inflammatory and lipid markers and oral glucose tolerance test was used to assess insulin sensitivity.

RESULTS

Reactive hyperemia decreased as body mass and fat mass increased. It also decreased with increasing neutrophil count. The Buckberg index was higher in males and was positively related to insulin sensitivity even when accounting for age, sex, and resting heart rate. AIx₇₅ was not related to any of the other variables.

CONCLUSIONS

These results demonstrate that increased fat mass and decreased insulin sensitivity are related to poorer vascular function and cardiac risk in adolescents before the development of actual cardiovascular disease.

Secular trends in the grip strength and body mass index of sport university students between 1973 and 2016: J-Fit＋study

Background/Objective

Sport university students are a unique population because they usually have a strong sport background since early childhood. In this study, we aimed to examine secular trends in grip strength of male, first-year sport university students in comparison with the general population between 1973 and 2016.

Methods

Existing data on the grip strength of 6,308 sport university students aged 18 years were examined. The data were obtained from the Juntendo Fitness Plus Study, a study of the Department of Physical Education/Health and Sports Science of Juntendo University. For reference, age- and sex-matched data (18 years old, male) on the grip strength were obtained from a national database.

Results

Compared with the general population, the sport university students had greater body mass index and stronger grip strength at all times.

Conclusions

The grip strength of sport university students significantly declined between the 1980s and 1990s, and it has plateaued since 2000, albeit at low levels. Compared with the peak performance of sport university students in 1984, the grip strength of students in 2016 was significantly lower by 8.1 kg. The downward trends were also confirmed in the general population during the same periods. In conclusion, the grip strength of sport university students has significantly declined over the last few decades.

Low muscle mass and strength in pediatrics patients: Why should we care?

Skeletal muscle plays major roles in metabolism and overall health across the lifecycle. Emerging evidence indicates that prenatal (maternal diet during pregnancy and genetic defects) and postnatal factors (physical activity, hormones, dietary protein, and obesity) influence muscle mass acquisition and strength early in life. As a consequence, low muscle mass and strength contributes to several adverse health outcomes during childhood. Specifically, studies demonstrated inverse associations of muscle mass and strength to single and clustered metabolic risk factors. The literature also consistently reports that low muscle mass and strength are associated with reduced bone parameters during growth, increasing the risk of osteoporosis in old age. Furthermore, muscle mass gains are associated with improved neurodevelopment in the first years of life. Given these negative implications of low muscle mass and strength on health, it is crucial to track muscle mass and strength development from childhood to adolescence. Several body composition techniques are currently available for estimation of muscle mass, all with unique advantages and disadvantages. The value of ultrasound as a technique to measure muscle mass is emerging in pediatric research with potential for translating the research findings to clinical settings. For the assessment of muscle strength, the handgrip strength test has been widely employed but without a standardized protocol. Although further research is needed to define normative data and cut points for the low muscle mass and strength phenotype, the use of such non-invasive medical monitoring is a promising strategy to identify early abnormalities and prevent low muscle mass in adulthood.

Grip Strength Is Associated with Longitudinal Health Maintenance and Improvement in Adolescents

OBJECTIVE

To assess the effects of muscle strength, as determined by grip strength, on changes in health status in adolescents.

STUDY DESIGN

Risk variables included excess body fat, elevated fasting glucose, high blood pressure, elevated serum triglycerides, and low high-density lipoprotein cholesterol. Multinomial logistic regression was used to quantify the odds of experiencing health maintenance (no risk factors identified at either time point) or health improvement (presence of ≥1 baseline risk factor and fewer or no risk factors at follow-up) over a 2-year period. The primary exposure variable was grip strength normalized by body mass (normalized grip strength [NGS]), and previous cut-offs were used to determine whether adolescents were weak or strong.

RESULTS

Adolescents who had low NGSs had a significantly greater prevalence of health decline or poor health persistence as compared with those who were strong (boys: 60.2% vs 15.3%; girls: 51% vs 21.9%; all P < .001). Moreover, adolescents who were strong had an increased adjusted odds for health maintenance (OR 3.54; 95% CI 1.80-6.97) and health improvement (OR 1.30; 95% CI 1.05-1.60), even after we adjusted for baseline fat-free mass index, cardiorespiratory fitness, and objectively measured physical activity.

CONCLUSIONS

Greater NGS is associated with longitudinal health maintenance and health improvements in adolescents. Low NGS could be used as a prognostic indicator of cardiometabolic risk and to identify adolescents who would benefit most from lifestyle interventions to improve muscular fitness.

The Role of Adiposity in the Association between Muscular Fitness and Cardiovascular Disease

OBJECTIVES

To test the associations of muscular fitness and body mass index (BMI), individually and combined, with clustered cardiovascular disease risk factors in children and adolescents and to analyze the mediator role of BMI in the association between muscular fitness and clustered cardiovascular disease risk factors.

STUDY DESIGN

In total, 239 children (113 girls) and 270 adolescents (128 girls) participated in this cross-sectional study. Height and weight were assessed, and BMI was calculated. A cardiovascular disease risk factors index (CVDRF-I) was created from the combination of the following variables: waist circumference, systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, and glucose. Handgrip strength/weight and standing long jump tests were used to assess muscular fitness. A muscular fitness index was computed from the combination of both tests.

RESULTS

Muscular fitness index was associated with CVDRF-I in children of both sexes and adolescent boys; however, these associations disappeared after accounting for BMI. BMI was associated with CVDRF-I in both children and adolescents, even after adjusting for muscular fitness (all P < .001). In male and female children and in adolescent boys, the association between muscular fitness and CVDRF-I was mediated by BMI (all P < .001). Because there was no association between muscular fitness and CVDRF-I in adolescent girls, the mediation hypothesis was discarded.

CONCLUSIONS

BMI is an independent predictor of CVDRF-I in children and adolescents of both sexes. Conversely, the effect of muscular fitness on CVDRF-I seems to be fully mediated by BMI levels in male and female children and in adolescent boys.

Changes in muscular fitness and its association with blood pressure in adolescents

The aims of this study were to examine the longitudinal association between muscular fitness (MF) and blood pressure (BP) 2 years later, and to determine whether changes in MF over a 2-year period were associated with BP at follow-up, in adolescents. The sample comprised 734 youths (349 girls) aged from 12 to 18 years. MF was assessed with the standing long jump and handgrip tests. Socioeconomic status, pubertal stage, waist circumference, resting BP, and cardiorespiratory fitness were measured according to standard procedures. Regression analyses showed a significant inverse association between MF at baseline and systolic BP (β = - 0.072; p = 0.032) and rate pressure product (β = - 0.124; p < 0.001) at follow-up, after adjustments for age, sex, height, pubertal stage, and socioeconomic status. However, when analyses were further adjusted for waist circumference and cardiorespiratory fitness, these associations did not remain significant. Adolescents with persistently high and increasing MF exhibited the lowest levels of diastolic BP (F_{(3, 721)} = 3.814, p = 0.018) and systolic BP (F_{(3, 721)} = 3.908, p = 0.014) when compared to those with persistent low MF after adjustment for age, sex, height, socioeconomic status, cardiorespiratory fitness, and waist circumference.Conclusion: This study suggests that persistent greater and increasing MF in youth are associated with lower levels of BP across the adolescence. What is Known: • Currently, there is a growing interest on the health benefits of muscular fitness. • Cross-sectional studies have identified an association between muscular fitness and blood pressure in adolescents. What is New: • Changes in muscular fitness during adolescence were associated with systolic and diastolic BP over a 2-year period. • Adolescents with persistently low muscular fitness exhibited the highest levels of diastolic and systolic BP.

Handgrip Strength and Blood Pressure in Children and Adolescents: Evidence From NHANES 2011 to 2014

BACKGROUND

Previous studies have reported that handgrip strength, a measure of muscular fitness, is associated with cardiovascular risk factors. However, the association of handgrip strength with blood pressure (BP) in children has been inconsistent. We tested the association of handgrip strength with systolic and diastolic BP in children and adolescents from the National Health and Nutrition Examination Survey (NHANES) 2011-2014.

METHODS

The study included 3,929 participants aged 8-19 years who underwent a handgrip test. The sum of the maximum handgrip strength from both hands was used. General linear models were used to examine the associations between handgrip strength and the outcome variables.

RESULTS

After adjustment for age, race, sex, body mass index, and physical activities, handgrip strength was significantly and positively associated with systolic (P < 0.0001) and diastolic (P = 0.01) BP. There was an increasing trend in systolic BP as handgrip strength increased from the bottom quartile to the top quartile, with 2.1 mm Hg difference between the top and the bottom quartiles (P for trend <0.0001). Similar results were observed for diastolic BP.

CONCLUSIONS

Muscular fitness is positively associated with BP in children and adolescents. The implications and underlying mechanisms for these results need further examinations.

Efficacy of Exercise Intervention for Weight Loss in Overweight and Obese Adolescents: Meta-Analysis and Implications

BACKGROUND

The global rise in obesity prevalence among children and adolescents has been linked to modifiable lifestyle factors, including lack of physical activity. However, no known meta-analysis has been conducted on the effects of exercise intervention on body composition and cardiometabolic risk factors in overweight and obese adolescents.

OBJECTIVES

The aim of this study was to (1) estimate whether exercise intervention meaningfully improves body composition and cardiometabolic risk factors in overweight and obese adolescents; and (2) discuss the implications of the findings in terms of primary healthcare provision and public health policy, using New Zealand as an exemplar context.

DATA SOURCES

Electronic databases (PubMed, Web of Science, SPORTDiscus, Google Scholar) from inception to May 2015. The reference lists of eligible articles and relevant reviews were also checked.

STUDY SELECTION

Inclusion criteria were (1) randomized controlled trial; (2) structured exercise intervention, alone or combined with any other kind of intervention; (3) control group received no structured exercise or behavioural modification designed to increase physical activity; (4) participants overweight or obese (body mass index [BMI] ≥85th percentile); and (5) participants aged between 10 and 19 years.

APPRAISAL AND SYNTHESIS METHODS

Initially, 1667 articles were identified. After evaluation of study characteristics, quality and validity, data from 13 articles (15 trials) involving 556 participants (176 male, 193 female, 187 unknown) were extracted for meta-analysis. Meta-analyses were completed on five body composition parameters and ten cardiometabolic parameters. Effect sizes (ESs) were calculated as mean differences, as well as standardized mean differences in order to determine effect magnitude.

RESULTS

Exercise intervention reduced BMI (mean 2.0 kg/m², 95 % CI 1.5-2.5; ES moderate), body weight (mean 3.7 kg, 95 % CI 1.7-5.8; ES small), body fat percentage (3.1 %, 95 % CI 2.2-4.1; ES small), waist circumference (3.0 cm, 95 % CI 1.3-4.8; ES small), but the increase (improvement) in lean mass was trivial (mean 1.6 kg, 95 % CI 0.5-2.6). The response to an oral glucose tolerance test following exercise intervention was for a decrease in the area under the curve for insulin (mean 162 μU/μl, 95 % CI 93-231; ES large) and blood glucose (mean 39 mg/dl, 95 % CI 9.4-69; ES moderate). Improvements in the homeostatic model assessment were also noted (mean 1.0, 95 % CI 0.7-1.4; ES moderate) and systolic blood pressure (mean 7.1 mmHg, 95 % CI 3.5-10.7; ES moderate). The effects of exercise on total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, fasting insulin and fasting blood glucose were inconclusive.

LIMITATIONS

Most of the included trials were short term (6-36 weeks) and 13 had methodological limitations. Additionally, the meta-analyses for some of the secondary outcomes had a small number of participants or substantial statistical heterogeneity.

CONCLUSIONS

The current evidence suggests that exercise intervention in overweight and obese adolescents improves body composition, particularly by lowering body fat. The limited available evidence further indicates that exercise intervention may improve some cardiometabolic risk factors.

Handgrip strength is associated with insulin resistance and glucose metabolism in adolescents: Evidence from National Health and Nutrition Examination Survey 2011 to 2014

BACKGROUND

Previous studies have reported that handgrip strength, a measure of muscular fitness, is associated with insulin resistance in children and adolescents, with conflicting results. Further, no studies have examined the association between handgrip strength with 2-hour glucose levels.

OBJECTIVE

We tested the association of handgrip strength with measures of insulin resistance (fasting insulin and homeostasis model assessment of insulin resistance [HOMA-IR]) and glucose metabolism (fasting and 2-hour glucose levels) in adolescents from the National Health and Nutrition Examination Survey (NHANES) 2011 to 2014.

METHODS

The study included 959 participants aged 12 to 19 years who underwent a handgrip test and a glucose tolerance test. General linear models were used to examine the associations between handgrip strength and the outcome variables.

RESULTS

After adjustment for age, race, sex, body mass index, and physical activities, handgrip strength was inversely associated with fasting insulin levels (P = .017) and HOMA-IR (P = .025). Although there was no association between handgrip strength and fasting glucose levels (P = .77), handgrip strength was inversely associated with 2-hour glucose levels (P < .0001). Insulin and 2-hour glucose levels decreased linearly as handgrip strength increased from the bottom quartile to the top quartile (P for trend: .045 for fasting insulin levels and .004 for 2-hour glucose levels).

CONCLUSIONS

Muscular fitness, measured by handgrip strength, is associated with insulin resistance and glucose metabolism in adolescents, which indicates that increasing muscular fitness may have beneficial effects for early prevention of insulin resistance and type 2 diabetes.

Handgrip strength is positively related to blood pressure and hypertension risk: results from the National Health and nutrition examination survey

Background

Isometric handgrip resistance exercise, a nonpharmacological lifestyle modification, has been recommended as a first-line treatment for hypertension. This study aimed to examine the relationship of handgrip strength to blood pressure and the risk of hypertension.

Methods

The responses and examination of 4597 participants in the National Health and Nutrition Examination Survey (NHANES) were analyzed in this study. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were transformed to age- and sex-specific z-scores. Handgrip strength was adjusted by weight (kg) and converted to an age- and sex-specific z-score. The relationships of SBP and DBP to handgrip strength were analyzed by Pearson correlation test and multivariable linear regression. Binary logistic regression was used to analyze the association between handgrip strength and prevalence of hypertension.

Results

Handgrip strength was positively related to higher DBP in men and women. In men, logistic regression models revealed that increased handgrip strength was associated with higher risk of hypertension after adjusting for age, BMI, smoking and drinking status; OR was 1.24 (95%CI: 1.04–1.48). After stratifying on BMI, handgrip strength was significantly associated with higher risk of hypertensions after adjusting for age, BMI, smoking and drinking status in overweight and obese men; OR was 1.31 (95%CI: 1.05–1.63). No significant associations were observed in women.

Conclusions

Increased handgrip strength is associated with higher DBP in men and women. In men, especially overweight and obese men, strong handgrip strength may be associated with higher risk of hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0734-4) contains supplementary material, which is available to authorized users.

Lower Performance in the Six-Minute Walk Test in Obese Youth With Cardiometabolic Risk Clustering

Background: Physical fitness is an important index of health. Our aim was to assess whether cardiorespiratory and/or musculoskeletal components of physical fitness were associated with cardiometabolic risk clustering in obese youth, using adapted and validated field tests. Methods: We evaluated 252 children and adolescents (132 males, 120 females), mean age 10.9 ± 1.9 years with primary obesity. All subjects performed the six-minute walk test (6MWT) for assessing aerobic fitness, the standing broad jump, and the 30 s-chair stand tests for lower-body muscular strength, and the handgrip test for upper body isometric strength. Cardiometabolic risk (CMR) clustering was defined as having two or more of the following risk factors: high SBP and/or DBP, impaired fasting glucose, high triglycerides (TGs), and low HDL-Cholesterol. Results: CMR clustering was found in 44 (17.5%) obese youth. Youth with CMR clustering had a lower cardiorespiratory fitness, as assessed by 6MWT, compared to those without CMR clustering. On the contrary, no difference was found with respect to musculoskeletal fitness. The six-minute walk (6MW) distance was negatively associated with sedentary time, controlling for age and height. CMR factors clustering was significantly associated with BMI standard deviation score (SDS) and negatively with 6MW distance: for each 10-m increase in the 6MW distance, a reduction of about 9% in the prevalence of CMR clustering was expected. Conclusions: A lower performance in the 6MWT may be considered as an additional trait of CMR clustering in obese youth. The 6MWT may represent a valuable, simple and low cost test to estimate the cardiorespiratory fitness in youth with obesity.

Evidence for increasing physical activity in children with physical disabilities: a systematic review

AIM

To summarize the best evidence of interventions for increasing physical activity in children with physical disabilities.

METHOD

A systematic review was conducted using an electronic search executed in Academic Search Elite, Academic Search Premier, CINAHL, Embase, MEDLINE, PEDro, PsychINFO, and SPORTDiscus up to February 2016. The selection of articles was performed independently by two researchers according to predetermined eligibility criteria. Data extraction, methodological quality, and levels of evidence were independently assessed by two researchers using a data-collection form from the Cochrane Collaboration and according to the guidelines of the American Academy for Cerebral Palsy and Developmental Medicine.

RESULTS

Seven studies were included. Five randomized controlled trials ranged from strong level I to weak level II studies, and two pre-post design studies were classified as level IV. There is level I evidence for no effect of physical training on objectively measured physical activity, conflicting level II evidence for interventions with a behavioural component on the increase of objectively measured physical activity directly after the intervention, and level II evidence for no effect during follow-up. Results are limited to children with cerebral palsy as no other diagnoses were included.

INTERPRETATION

Increasing physical activity in children with physical disabilities is very complex and demands further development and research.

Muscle Weakness Thresholds for Prediction of Diabetes in Adults

BACKGROUND

Despite the known links between weakness and early mortality, what remains to be fully understood is the extent to which strength preservation is associated with protection from cardiometabolic diseases, such as diabetes.

PURPOSE

The purposes of this study were to determine the association between muscle strength and diabetes among adults, and to identify age- and sex-specific thresholds of low strength for detection of risk.

METHODS

A population-representative sample of 4066 individuals, aged 20-85 years, was included from the combined 2011-2012 National Health and Nutrition Examination Survey (NHANES) data sets. Strength was assessed using a handheld dynamometer, and the single highest reading from either hand was normalized to body mass. A logistic regression model was used to assess the association between normalized grip strength and risk of diabetes, as determined by haemoglobin A1c levels ≥6.5 % (≥48 mmol/mol), while controlling for sociodemographic characteristics, anthropometric measures and television viewing time.

RESULTS

For every 0.05 decrement in normalized strength, there were 1.26 times increased adjusted odds for diabetes in men and women. Women were at lower odds of having diabetes (odds ratio 0.49; 95 % confidence interval 0.29-0.82). Age, waist circumference and lower income were also associated with diabetes. The optimal sex- and age-specific weakness thresholds to detect diabetes were 0.56, 0.50 and 0.45 for men at ages of 20-39, 40-59 and 60-80 years, respectively, and 0.42, 0.38 and 0.33 for women at ages of 20-39, 40-59 and 60-80 years, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

We present thresholds of strength that can be incorporated into a clinical setting for identifying adults who are at risk of developing diabetes and might benefit from lifestyle interventions to reduce risk.

Muscular strength and endurance and cardio-metabolic health in disadvantaged Hispanic children from the U.S

The predictive relationship between muscular strength and endurance and cardio-metabolic health, independent from aerobic fitness, is not clear in disadvantaged Hispanic children. The purpose of this study was to examine the predictive relationship between muscular strength and endurance and clustered cardio-metabolic risk, controlling for aerobic fitness, in Hispanic children from low-income schools. Participants were 320 Hispanic children (Mean age = 10.1 ± 1.1 years; 164 girls, 156 boys) recruited during the 2014-2015 and 2015-2016 academic years from five low-income schools from the state of Utah in the U.S. Muscular strength and endurance was assessed using the push-up and curl-up tests and estimated VO2 Peak was calculated from the Progressive Aerobic Cardiovascular Endurance Run. A clustered metabolic syndrome composite score (MetS) was calculated from cardio-metabolic health measurements consisting of HDL cholesterol, triglycerides, waist circumference, blood glucose, and mean arterial pressure (MAP). Multi-level general linear mixed effects models were used to examine the predictive relationship between muscular strength and endurance and MetS, controlling for the effect of aerobic fitness and the clustering of children within classrooms and schools. Children who were in the middle and upper tertiles for muscular strength and endurance associated with a lower (more favorable) MetS score (middle tertile: β = - 2.59, 95% C.I. [- 4.23, - 0.95], p < 0.05; upper tertile: β = - 1.57, 95% C.I. [- 3.20, - 0.16], p < 0.05). The results suggest that higher levels of muscular strength and endurance relate to lower cardio-metabolic risk, independent of aerobic fitness, in Hispanic children from low-income schools.

Muscle strength is associated with lower diastolic blood pressure in schoolchildren

Cardiorespiratory fitness (CRF) provides protection against the elevated blood pressure in overweight youth. Less is known regarding any similar protective effect of muscular fitness. We investigated how handgrip strength, an easy to implement measure of muscular strength, interacted with CRF and BMI to determine blood pressure in youth. We measured systolic (SBP) and diastolic (DBP) blood pressure, handgrip strength (HG), CRF and body mass index (BMI) in n=7329 10-16year-olds (47% girls). We defined elevated blood pressure as >91st percentile and Good HG as >33rd percentile. Participants were classified as Fit or Unfit and as Normal or Overweight/Obese based on international standards. The prevalence of elevated SBP was 23%, and 44% of participants had elevated DBP. In unfit participants Good HG was associated with lower SBP (z=0.41 (95%CI: 0.20-0.61) and DBP (z=0.29 (95%CI: 0.12-0.47). In Overweight/Obese participants, DBP was z=0.24 (95%CI: 0.14-0.34) lower in the Good (versus Low) HG group. Overweight/Obese participants with Good HG also had a 32% lower risk of elevated DBP (OR: 0.68, 95%CI: 0.57-0.82). This association was attenuated but remained important after adjusting for BMI (20% risk reduction, OR: 0.80, 95%CI: 0.63-1.01). Muscular fitness appears to play some protective role against the risk of elevated blood pressure; particularly for the more prevalent measure: elevated DBP (44%). Effects may be restricted to Overweight / Obese or unfit youth, who have an increased risk of elevated BP and also may be less likely to engage in traditional cardiorespiratory fitness training. Research to determine the effects of muscular fitness training on blood pressure is warranted in these subgroups.

Nutritional status and weakness following pediatric hematopoietic cell transplantation

Survivorship after pediatric HCT has increased over the past decade. Focus on long-term care and well-being remains critical due to risk of poor dietary habits and exaggerated sedentary behavior, which can lead to muscle weakness, increased risk for obesity, and cardiometabolic disorders. Nutrition and physical activity are key factors in survivorship; however, data are limited. Comprehensive nutritional assessments, including nutrition-focused physical examination, grip strength, and food/activity surveys, were completed in 36 pediatric HCT survivors (aged 2-25 years). Patients were divided into undernutrition, normal-nutrition, and overnutrition categories. Fifty percent of participants were classified as normal nutrition, 22% undernutrition, and 28% overnutrition. Few patients met the U.S. Dietary Guidelines recommended intake for vegetables, fiber, saturated fat, and So FAS. Patients in the undernutrition group demonstrated significantly lower grip strength than those in the normal- and overnutrition groups. When grip strength was normalized to body mass, patients in the overnutrition group had the highest prevalence of weakness. Using NHANES reference data, maximum grip strength and NGS cutoffs were identified that could significantly distinguish the nutrition groups. Comprehensive nutritional assessments and grip strength measurements are feasible, non-invasive, easy to perform, and inform both under- and overnutrition in pediatric HCT survivors.

Exercise and physical activity recommendations for people with cerebral palsy

Physical activity and its promotion, as well as the avoidance of sedentary behaviour, play important roles in health promotion and prevention of lifestyle-related diseases. Guidelines for young people and adults with typical development are available from the World Health Organisation and American College of Sports Medicine. However, detailed recommendations for physical activity and sedentary behaviour have not been established for children, adolescents, and adults with cerebral palsy (CP). This paper presents the first CP-specific physical activity and exercise recommendations. The recommendations are based on (1) a comprehensive review and analysis of the literature, (2) expert opinion, and (3) extensive clinical experience. The evidence supporting these recommendations is based on randomized controlled trials and observational studies involving children, adolescents, and adults with CP, and buttressed by the previous guidelines for the general population. These recommendations may be used to guide healthcare providers on exercise and daily physical activity prescription for individuals with CP.