Muscular strength in male adolescents and premature death: cohort study of one million participants

Temporal changes in the physical fitness of Chinese adolescents aged 13-18 years: an analysis of eight national successive surveys over three decades

Objective

The aim of this study was to assess temporal changes in physical fitness of Chinese adolescents aged 13-18 years from 1985 to 2019.

Methods

Body size /composition and physical fitness indicators, including body height, weight, body mass index (BMI), speed, power, flexibility, muscular endurance, and cardiorespiratory fitness (CRF), were selected from Chinese boys and girls aged 13-18 years from eight Chinese National Surveillance on Students' Constitution and Health from 1985 to 2019. Temporal changes in means were estimated by sample-weighted linear regression at the test × sex × age level, and national trends were estimated by a post-stratification population weighting procedure.

Results

Overall mean body height, weight and BMI increased significantly for Chinese adolescents over 34 years. There was a small improvement for boys in speed (Effect size [ES] = -0.21, 95% confidence interval [CI] = -0.44 ~ 0.02), a small improvement for boys in power (ES = 0.24, 95% CI = -0.20 ~ 0.69), a small improvement for girls in flexibility (ES = 0.45, 95% CI = 0.15 ~ 0.76), a moderate decline for boys (ES = -0.53 95% CI = -0.84 ~ -0.21) and a moderate improvement for girls (ES = 0.61, 95% CI = -0.03 ~ 1.26) in muscular endurance, and large declines in cardiorespiratory fitness (CRF) for boys (ES = 0.93, 95% CI = 0.64 ~ 1.21) and girls (ES = 0.93, 95% CI = 0.58 ~ 1.27) from 1985 to 2019. These trends in each component of fitness were more positive for adolescents aged 13-15 years than that of adolescents aged 16-18 years in both sexes, except for girls in flexibility.

Conclusion

The decline in CRF was most pronounced among Chinese children and adolescents from 1985 to 2019, suggesting a future decline in population health that needs attention.

Higher body mass index was associated with a lower mortality of idiopathic pulmonary fibrosis: a meta-analysis

PURPOSE

In the past few years, there has been a notable rise in the incidence and prevalence of idiopathic pulmonary fibrosis (IPF) on a global scale. A considerable body of research has highlighted the 'obesity paradox,' suggesting that a higher body mass index (BMI) can confer a protective effect against numerous chronic diseases. However, the relationship between BMI and the risk of mortality in IPF patients remains underexplored in the existing literature. We aim to shed light on this relationship and potentially offer novel insights into prevention strategies for IPF.

METHODS

We conducted a systematic search of the PubMed, Embase, and Web of Science databases to collect all published studies examining the correlation between Body Mass Index (BMI) and the mortality risk in patients with IPF, up until February 14, 2023. For the synthesis of the findings, we employed random-effects models. The statistical significance of the association between BMI and the mortality risk in IPF patients was evaluated using the hazard ratio (HR), with the 95% Confidence Interval (CI) serving as the metric for effect size.

RESULTS

A total of 14 data sets involving 2080 patients with IPF were included in the meta-analysis. The combined results of the random-effects models were suggestive of a significant association between lower BMI and a higher risk of death (HR = 0.94, 95% CI = 0.91-0.97, P < 0.001). For baseline BMI, the risk of death from IPF decreased by 6% for each unit increase. The results of the subgroup analysis suggest that geographic location (Asian subgroup: HR = 0.95, 95%CI = 0.93-0.98, P = 0.001; Western subgroup: HR = 0.91, 95%CI = 0.84-0.98, P = 0.014), study type (RCS subgroup: HR = 0.95, 95%CI = 0.92-0.98, P = 0.004; PCS subgroup: HR = 0.89, 95%CI = 0.84-0.94, P < 0.001), and sample size (< 100 groups: HR = 0.93, 95%CI = 0.87-1.01, P = 0.079; >100 groups: HR = 0.94, 95%CI = 0.91-0.97, P < 0.001 ) were not significant influences on heterogeneity. Of the included literature, those with confounding factors corrected and high NOS scores reduced heterogeneity (HR = 0.93, 95%CI = 0.90-0.96, P < 0.001). Sensitivity analyses showed that the combined results were stable and not significantly altered by individual studies (HR = 0.93 to 0.95, 95% CI = 0.90-0.96 to 0.92-0.98). Egger's test suggested no significant publication bias in the included studies (P = 0.159).

CONCLUSIONS

Higher BMI (BMI ≥ 25 kg/m2) is negatively correlated to some extent with the risk of death in IPF patients, and BMI may become a clinical indicator for determining the prognosis of IPF patients.

Diagnostic criteria, prevalence, and clinical outcomes of pediatric sarcopenia: A scoping review

BACKGROUND & AIMS

Sarcopenia, characterized by loss of muscle mass and decreased muscle strength, significantly affects adults but also influences pediatric health. However, definitions for low muscle mass, decreased strength, and sarcopenia in children are less established, impacting interventions for improving health outcomes. The objective of this scoping review is synthesize the existing literature on the diagnostic criteria, prevalence and clinical outcomes of sarcopenia.

METHODS

A scoping review, following the PRISMA extension for scoping reviews, examined pediatric sarcopenia literature until June 2023. The literature search was performed using MEDLINE and the Cochrane Central Register of Controlled Trials with the last search conducted on June 30, 2023. Criteria included studies on aged 0-20 years, covering healthy subjects, acutely ill patients, and chronic disease cases excluding specific conditions like neuromuscular diseases or prematurity.

RESULTS

Initial search found 503 studies, finally, we included 56 studies. Most studies diagnosed sarcopenia using skeletal muscle mass indicators like total psoas muscle area from Computed Tomography or Magnetic Resonance Imaging. Around half of the longitudinal studies highlighted sarcopenia as a risk factor for various clinical outcomes, predominantly in hospitalized patients. However, cutoff values for sarcopenia indicators lacked consistency, with studies employing diverse percentile-based measurements or z-scores.

CONCLUSION

Pediatric sarcopenia diagnosis primarily relies on skeletal muscle mass, with identified links to future clinical outcomes in specific conditions. The lack of standardized cutoffs for sarcopenia indicators underscores the necessity for age, gender, and race-specific cutoff values derived from studies establishing reference values for muscle mass and strength across diverse pediatric populations.

Influence of Preterm Birth and Low Birthweight on Physical Fitness: A Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND

Preterm birth and low birthweight (LBW) might be associated with reduced physical fitness, although evidence remains inconclusive.

OBJECTIVE

To examine the influence of preterm birth and LBW on physical fitness, as well as to assess whether variables such as gestational age, birthweight, or age at assessment moderate these effects.

METHODS

PubMed, Scopus, and PsycINFO were systematically searched from inception to 7 December 2023 for case-control and cohort studies analyzing the association between preterm birth or LBW (or gestational age or birthweight as continuous variables) with at least one physical fitness-related outcome (i.e., cardiorespiratory fitness (CRF), muscle strength, flexibility, speed, agility). Random-effects meta-analysis and meta-regression models were used to estimate the pooled effect size, as well as to examine potential associations between the magnitude of the effect and gestational age, birthweight, or age at assessment.

RESULTS

Fifty-two studies (n = 920,603 participants, average age ranging from 4.7 to 34.4 years) were included. Preterm birth was associated with reduced CRF (standardized mean difference (SMD) = -0.38, 95% confidence interval (CI) = -0.51 to -0.25) and muscle strength (SMD = -0.44, 95% CI = -0.79 to -0.08). LBW was associated with reduced CRF (SMD = -0.40, 95% CI = -0.64 to -0.17), muscle strength (SMD = -0.18, 95% CI = -0.24 to -0.13), flexibility (SMD = -0.11, 95% CI = -0.22 to -0.01), and agility (SMD = -0.99, 95% CI = -1.91 to -0.07). Meta-regression analyses showed that a lower gestational age or birthweight were associated with larger reductions in physical fitness, whereas no consistent association was found for the age at assessment.

CONCLUSION

Both preterm birth and LBW seem associated with reduced physical fitness regardless of age, with larger reductions overall observed in individuals with lower gestational age or birthweight. These findings might support the implementation of preventive strategies (e.g., fitness monitoring and physical exercise interventions) in these populations through the life course. PROSPERO registration: CRD42021231845.

Association of handgrip strength with suicidal ideation among adults aged ≥50 years from low- and middle-income countries

INTRODUCTION

This study aimed to investigate the association between handgrip strength and suicidal ideation in representative samples of adults aged ≥50 years from six LMICs (China, Ghana, India, Mexico, Russia, and South Africa).

METHODS

Cross-sectional, community-based data from the World Health Organization's Study on Global Aging and Adult Health were analyzed. Handgrip strength quintiles by sex were created based on the average value of two handgrip measurements of the dominant hand. Self-reported information on past 12-month suicidal ideation was collected. Multivariable logistic regression analysis was conducted to assess associations.

RESULTS

Data on 34,129 individuals were analyzed [mean (SD) age 62.4 (16.0) years; age range 50-114 years; 52.1% females]. After adjustment for potential confounders, in the overall sample, compared to the handgrip strength quintile with the highest values [Quintile 1 (Q1)], Q2, Q3, Q4, and Q5 were associated with significant 2.15 (95% CI = 1.05-4.39), 2.78 (95% CI = 1.06-7.32), 3.53 (95% CI = 1.68-7.42), and 6.79 (95% CI = 2.80-16.48) times higher odds for suicidal ideation.

CONCLUSIONS

Lower handgrip strength was significantly and dose-dependently associated with higher odds for suicidal ideation in adults aged ≥50 years from LMICs. Future longitudinal studies are needed to understand the underlying mechanisms, and whether increasing general muscular strength and physical function may lead to reduction in suicidal ideation.

Accelerometer-Measured Physical Activity, Fitness and Indicators of Cardiometabolic Risk among Rural Adolescents: A Cross-Sectional Study at 15-Year Follow-up of the MINIMat Cohort

BACKGROUND

Little is known about the relationship of physical activity (PA) and fitness with cardiometabolic risk among rural adolescents in low- and middle-income countries. Thus, we examined the associations of PA and fitness with selected cardiometabolic indicators along with potential gender-based differences in a birth cohort of rural adolescents from southeast Bangladesh.

METHODS

We utilized data from the 15-year follow-up of Maternal and Infant Nutrition Interventions in Matlab (MINIMat) cohort (n = 2253). Wrist-worn ActiGraph wGT3x-BT accelerometers were used to estimate sedentary time (ST) and PA. Fitness was assessed using: handgrip strength, standing long jump, and Chester Step Test. Anthropometric parameters, systolic blood pressure (SBP), and fasting lipid, insulin and glucose levels were measured. We calculated insulin resistance using the Homeostasis Model Assessment equation (HOMA-IR). Linear regression and isotemporal substitution models were fitted.

RESULTS

The adolescents spent 64 min/day (inter-quartile range: 50-81) in moderate-to-vigorous physical activity (MVPA). A 10-minute-per-day higher vigorous PA (VPA) was associated with: 4.9% (95% confidence interval (CI): 2.9-6.8%) lower waist circumference (WC), 3.2 mmHg (95% CI: 1.5-4.8) lower SBP, 10.4% (95% CI: 2.9-17.3%) lower TG, and 24.4% (95% CI: 11.3-34.9%) lower HOMA-IR. MVPA showed similar associations of notably smaller magnitude. Except for WC, the associations were more pronounced among the boys. Substituting ST with VPA of equal duration was associated with lower WC, SBP, triglyceride and HOMA-IR. Grip strength was favorably associated with all indicators, displaying considerably large effect sizes.

CONCLUSION

Our findings indicated beneficial roles of PA- particularly VPA- and muscular fitness in shaping cardiometabolic profile in mid-adolescence. VPA and grip strength may represent potential targets for preventive strategies tailored to adolescents in resource-limited settings.

Exploring the Association between Elevated Anxiety Symptoms and Low Skeletal Muscle Mass among Asymptomatic Adults: A Population-Based Study in Republic of Korea

Individuals with mental health problems are at higher risk of musculoskeletal diseases. However, the association between low muscle mass (LMM) and anxiety symptoms remains uninvestigated. This cross-sectional study enrolled 174,262 adults (73,833 women, 100,429 men), aged 18 to 89, who completed the anxiety scale and body composition analyses. Using bio-electrical impedance analysis, skeletal muscle mass index (SMI) was calculated based on appendicular skeletal muscle mass (ASM) (kg)/height (m2). LMM was defined as SMI < 7.0 kg/m2 in men and <5.4 kg/m2 in women. Anxiety symptoms were screened using the Clinical Useful Anxiety Outcome Scale (CUXOS) with cut-off scores of 20, 30, and 40. Multivariable logistic regression analyses were performed. LMM prevalence was 20.17% in women, 3.86% in men (p < 0.001). The prevalence of anxiety symptoms in LMM group decreased from mild (CUXOS > 20: women, 32.74%, men, 21.17%) to moderate (CUXOS > 30: 13.34%, 7.32%), to severe anxiety symptoms (CUXOS > 40: 4.00%, 1.73%). In multivariable-adjusted models, LMM was associated with mild (aOR (95% confidence interval)), women, 1.13 (1.08-1.17); men, 1.17 (1.08-1.27)), moderate (1.17 (1.11-1.24); 1.35 (1.19-1.53) and severe anxiety symptoms (1.18 (1.07-1.3), 1.36 (1.06-1.74)), demonstrating an increased risk of ORs with escalating anxiety severity. LMM was independently associated with a higher prevalence of anxiety symptoms.

Mediation effects of lean mass and fat mass on the relationship between body mass index and handgrip strength

OBJECTIVE

This study aimed to assess the mediation effects of lean mass and fat mass on the relationship between body mass index (BMI) and handgrip strength (HGS) in adolescents.

METHOD

The sample included 118 adolescents (60 girls) aged 10-14 years. Body composition, determined from lean mass (LM) and fat mass (FM), was measured by dual-energy x-ray absorptiometry. HGS was measured using a digital dynamometer. Moderate-to-vigorous physical activity and sexual maturation, treated as covariates, were evaluated by accelerometry and pubic hair development, respectively. Spearman correlation and simple mediation analysis were used for statistical analysis.

RESULTS

A positive relationship was observed between BMI and HGS (rho = .364, p < .001), BMI and LM (rho = .466, p < .001), LM and HGS (rho = .784, p < .001), BMI and FM (rho = .907, p < .001), and FM and HGS (rho = .291, p = .001). LM was the only significant mediator of the relationship between BMI and HGS.

CONCLUSION

Only LM mediated the association between BMI and HGS, almost entirely explaining the relationship. The findings reinforce the need to include LM measurements in routine strength testing. Furthermore, strategies focused on LM development may be promising in preventing low muscle strength in adolescents.

Associations between Multiple Health Indicators and Carotid Artery Intima-Media Thickness in A Healthy and Active Elderly Population

The purpose of this study was to examine correlations between health indicators (age, BMI, blood pressure (BP), functional strength (FS), handgrip strength, and predicted VO2 max) and carotid intima-media thickness (cIMT) in an active 50 years+ population. Study participants' mean cIMT was also compared to the cIMT mean of the general population. Health screenings were conducted on 1818 participants at the Huntsman World Senior Games from 2016 to 2019. Pearson's correlations, Spearman's correlations, and ANOVA were performed using SPSS. Weak but significant correlations were evident between cIMT and age (r = 0.283, p < 0.001), systolic BP (r = 0.253, p = 0.001), diastolic BP (r = 0.074, p = 0.016), weight (r = 0.170, p < 0.001), height (r = 0.153, p < 0.001), handgrip L (r = 0.132, p < 0.001), handgrip R (r = 0.074, p < 0.029), and BMI (r = 0.07, p = 0.029); non-significant correlations were evident with predicted VO2 max (r = -0.035, p = 0.382), and FS (r = -0.025, p = 0.597). When controlling for age, systolic BP, and sex, only handgrip L (r = 0.225, p = 0.014) was significantly correlated with cIMT. Mean cIMT for this cohort was lower across all sexes and age-matched groups (cIMT = 0.6967 mm (±0.129)). Physical activity is linked to reduced cIMT. Most health-related indicators in this study were significantly but weakly correlated with cIMT. Additional research is needed before common indicators can be used as a surrogate for cIMT and CVD risk. Results from this study can provide clinicians with additional information to reduce CVD risk through modifiable risk factors. Classic CVD risk factors such as systolic BP and BMI should be considered in patients regardless of lifestyle.

Mortality and disability risk among older adults unable to complete grip strength and physical performance tests: a population-based cohort study from China

BACKGROUND

The link between low grip strength, diminished physical performance, and adverse health outcomes in older adults has been well-established. However, the impact of older adults who cannot complete these tests on disability and mortality rates remains unexplored without longitudinal study.

METHODS

We collected data from the China Health and Retirement Longitudinal Study (CHARLS). Participants aged 60-101 were enrolled at baseline. We analyzed the prevalence of populations unable to complete handgrip strength (HGS), gait speed (GS), and five times chair stand test (FTCST). Completing risk models were used to estimate the risk of mortality and disability over seven years.

RESULTS

A total of 3,768 participants were included in the analysis. The percentage of older adults unable to complete the GS and FTCST tests increased notably with age, from 2.68 to 8.90% and 2.60-20.42%, respectively. The proportion of older people unable to perform the HGS was relatively stable, ranging from 1.40 to 3.66%. Compared to older adults who can complete these tests, those who cannot perform FTCST face a significantly higher risk of mortality, with 49.1% higher risk [hazard ratio (HR) = 1.491, 95% CI = 1.156, 1.922; subdistribution hazard ratio (SHR) = 1.491, 95%CI = 1.135,1.958)]. Participants who were unable to complete the GS test had a higher risk of developing ADL disability, regardless of whether they were compared to the lowest-performing group (HR = 1.411, 95%CI = 1.037,1.920; SHR = 1.356, 95%CI = 1.030,1.785) or those who can complete the GS (HR = 1.727, 95%CI = 1.302,2.292; SHR = 1.541, 95%CI = 1.196,1.986). No statistically significant difference in the risk of developing ADL disability among older adults who were unable to complete the HGS test compared with either the poorest performing group (HR = 0.982, 95% CI = 0.578, 1.666; SHR = 1.025, 95% CI = 0.639, 1.642) or those who were able to complete the HGS test (HR = 1.008, 95% CI = 0.601, 1.688; SHR = 0.981, 95% CI = 0.619, 1.553). The risk of all-cause mortality was not significantly different for older adults who were unable to complete the HGS test compared to those with the worst performance (HR = 1.196, 95%CI = 0.709-2.020; SHR = 1.196, 95%CI = 0.674, 2.124) or those who were able to complete the test (HR = 1.462, 95%CI = 0.872-2.450; SHR = 1.462, 95%CI = 0.821,2.605).

CONCLUSION

The risks of adverse events faced by older adults unable to complete the tests vary, indicating the necessity for future research to conduct separate analyses on this high-risk population.

How to design and establish a national school-based physical fitness monitoring and surveillance system for children and adolescents: A 10-step approach recommended by the FitBack network

BACKGROUND

Providing individual- and population-level data on children's physical fitness (PF) is a crucial public health and education priority. However, few national fitness monitoring or surveillance systems are currently in practice internationally. We aim to summarize the current European PF monitoring and surveillance systems for school-aged children and to provide experience-based guidelines on how to design such systems.

METHODS

The FitBack network consists of experts from diverse backgrounds with the common interest to improve the accessibility of PF monitoring for young people globally. Through FitBack network, we identified and compared the national or regional PF monitoring and surveillance systems currently in operation across Europe. We formulated a 10-step approach for designing and establishing one's own system, based on analysis of experienced strengths, weaknesses, opportunities, and threats to monitoring childhood fitness.

RESULTS

We identified a total of eight PF monitoring systems in Finland, France, Galicia of Spain, Hungary, Lithuania, Portugal, Serbia, and Slovenia. The FitBack network recommends the following steps for designing and establishing one's own system: (1) set up mission statements and aims, (2) involve stakeholders, (3) utilize scientific background, (4) governance structure, (5) ensure sufficient funding, (6) data management planning, (7) provide meaningful feedback, (8) conduct pilot testing, (9) plan implementation process, and (10) invest in communication with stakeholders.

CONCLUSIONS

This study provides an updated overview of the best practices for school-aged children's fitness monitoring and surveillance in Europe. Additionally, it offers a 10-step approach to assist in the creation of similar systems in Europe or globally.

Clustered Cardiometabolic Risk and the "Fat but Fit Paradox" in Adolescents: Cross-Sectional Study

The "fat but fit paradox" states that people who are fit have a lower cluster cardiometabolic risk (CCMR), even if they are overweight or obese. Therefore, the objective was to investigate the CCMR between four categories based on the "fat but fit paradox" variable, in different fitness categories-cardiorespiratory fitness, muscular fitness, and physical fitness-in adolescents. Body composition, cardiorespiratory fitness, muscle fitness, blood samples, and blood pressure were assessed in 230 adolescents, and cardiometabolic risk and three different "fat but fit paradox" variables were calculated. Participants with a higher CRF exhibited a lower CCMR within their body mass index (BMI) category (p < 0.05). Participants with a high BMI and high muscular fitness showed a lower CCMR than participants with a low muscular fitness and a similar BMI, or low BMI and low muscular fitness (p < 0.05). When both variables, CRF and muscular fitness, were combined, their effectabove CCMR increased (p < 0.05). Across all fitness categories, the fat and unfit group, whether considered individually or combined, exhibited the highest risk of CCMR (p < 0.05). This study confirms the "fat but fit paradox" in different physical fitness categories, showing the importance of both CRF and muscular fitness as predictors of CCMR, with the combination of both variables showing a greater agreement.

Evaluation of physical fitness and health of young children aged between 3 and 6 based on cluster and factor analyses

BACKGROUND

As life improves and sedentary time increases, young children's physical fitness gradually declines.

METHODS

Multi-stage stratified whole cluster sampling was utilized to sample 5584 preschoolers. Young infants' morphology, function, and quality were revealed using cluster and factor analysis.

RESULTS

The cluster analysis separated 3-6-year-olds into two genders: 1,551 men in group A "high physical fitness" 1,499 men in group B "low physical fitness"; 1,213 women in group A and 1,321 women in group B. Young children's fitness was measured by standing long jump(1.00), weight(1.00), and height(1.00). A cluster analysis of 3-4-year-olds classified them into three groups: 272 "muscular strength," 75 "average physical fitness," and 250 "low agility." Young children's health depends on weight (1.00), height (0.57), and chest circumference (0.54). A cluster analysis of the 4-5-year-olds classified them into two groups: 1070 "balance" and 806 "muscular strength." Young children's health depends on weight (1.00), height (0.74), and chest circumference (0.71). A cluster analysis of the 5-6-year-olds divided them into three groups: 1762 "high physical fitness," 384 "obese," and 105 "low physical fitness." Young children's physical health depends on BMI (1.00), weight (1.00), and chest circumference (1.00). Factor analysis demonstrated that muscle strength, body shape, cardiovascular variables, and physical fitness composite components affected young children's health.

CONCLUSION

Women should focus on motor function and strength, while men on flexibility. Male group B "low physical fitness" should focus on strength, motor function, and balance, whereas male group A "high physical fitness" should focus on flexibility. Then, female group A "high physical fitness" should emphasize variety.2) For 3-4-year-olds, group A "muscular strength" should focus on flexibility, and group C "low agility" on motor function. 3) For 4-5-year-olds, group A "balanced" should focus on strength and motor function; 4) For 5-6-year-olds, group B "obese" should emphasize weight loss, and group C "low fitness" should emphasize strength, motor function, and flexibility; 5) Young children's physical fitness depends on muscle strength, body shape, cardiovascular factors, and physical fitness composite.

Health-related physical fitness, physical activity and its correlates among school going adolescents in hilly state in north India: a cross sectional survey

INTRODUCTION

Health-related physical fitness, which includes body composition, cardiorespiratory fitness, muscular endurance, flexibility, power, and strength are associated with risks of chronic diseases and promote good health and wellness. There have been reports of increasing levels of physical inactivity among children and adolescents, leading to increasing rates of obesity and decreased physical fitness. The present study was conducted among school going adolescents to estimate the levels and correlates of PF for timely intervention.

METHODOLOGY

School based cross-sectional study was done among students of class 8-11th in Government schools of Garhwal division of Uttarakhand. Multistage stratified random sampling was applied for recruitment of study participants. We recruited a final sample size of 634 students. Validated questionnaires and standard methods for assessment of physical fitness, physical activity levels and other variables such as waist circumference, hip circumference, BMI and hemoglobin estimation were done.

RESULTS

Average and above average cardiorespiratory fitness score as per Harvard step test among boys (54.3%) was significantly higher as compared to girls (21.3%) (χ2 = 88.93, p < 0.001). There was a significant association between gender and dominant handgrip strength (χ2 = 8.02, p = 0.01) as well as between gender and Shoulder stretch test (SST) of dominant (χ2 = 17.5, p < 0.05) as well as nondominant arm (χ2 = 13.5, p < 0.05). Sit and reach test results also showed a significant association with gender (χ2 = 27.17, p < 0.001). Gender, hemoglobin level, BMI and PAL scores significantly predicted cardiorespiratory fitness scores (R2 = 0.188, F value of the model = 37.69, p =< 0.001)).

CONCLUSION

Physical fitness of school going adolescents in Garhwal division of Uttarakhand was better than other parts of India, with significant gender differences. Physical activity levels (PAL) were poor and are also a significant predictor of physical fitness. More emphasis needs to be paid on the health and fitness of girl students. School based policies to increase PAL among students through innovation and rewards may go a long way in improving the long-term health of the students.

Interaction between handgrip strength and vitamin D deficiency on all-cause mortality in community-dwelling older adults: a prospective cohort study

OBJECTIVE

Muscle strength decline and vitamin D deficiency are coexisting conditions associated with multiple adverse health outcomes. This prospective study aimed to investigate the multiplicative and additive interactions between handgrip strength (HS) and serum 25-hydroxyvitamin D [25(OH)D] on all-cause mortality in Chinese community-dwelling older adults.

STUDY DESIGN

This is a population-based cohort study.

METHODS

2635 older adults (85.15 ± 12.01 years) were recruited from the Chinese Longitudinal Healthy Longevity Survey (2012-2018). Low HS was defined according to the Asian Working Group for Sarcopenia 2019 updated consensus (<28 kg for men and <18 kg for women). Serum 25(OH)D < 50 nmol/L were defined as vitamin D deficiency. Cox proportional hazard models were used to examine the association of HS and 25(OH)D with all-cause mortality. Socio-demographics, health status, and clinical characteristics were included as covariates.

RESULTS

1715 (65.09 %) and 1885 (71.54 %) participants had low HS and vitamin D deficiency, respectively. During a median follow-up of 3.52 years, 1107 older people died. After multivariable adjustment, both HS and 25(OH)D levels were inversely associated with all-cause mortality risk (Ps < 0.001). The hazard ratios (HRs) of low HS and vitamin D deficiency for all-cause mortality were 1.73 (95 % CI: 1.41-2.13) and 1.61 (95 % CI: 1.32-1.93), respectively. Although significant multiplicative interactions were not found, the association between low HS and all-cause mortality was attenuated in the higher 25(OH)D subgroup than in the lower 25(OH)D subgroup (stratified by 50 nmol/L). The multiple-adjusted HR of mortality for combined low HS and vitamin D deficiency was 2.18 (95 % CI: 1.73-2.56), which was higher than that for these two conditions alone. Significant additive interactions between low HS and vitamin D deficiency on mortality were observed (relative excess risk due to interaction: 0.71, 95 % CI: 0.37-1.05).

CONCLUSIONS

Low HS and low 25(OH)D levels synergistically increased the risk of all-cause mortality. Our results added new insights to the priority of early detection for older adults with comorbid muscle strength decline and vitamin D deficiency.

Effects of measurement protocols and repetitions on handgrip strength weakness and asymmetry in patients with cancer

BACKGROUND

The use of handgrip strength (HGS) in clinical cancer research is surging. The association between HGS and outcomes in patients with cancer varied across studies, which might be due to the different measurement protocols for HGS. We aimed to answer three questions: (1) Did the use of various protocols for HGS, along with different numbers of repetitions, lead to significant differences in maximum HGS values? (2) If yes, were these differences clinically significant? (3) Did the differences in HGS protocols and repetitions affect the identification of HGS weakness or HGS asymmetry?

METHODS

We continuously recruited adult patients with solid tumours. Two protocols were used to measure HGS: Method A, following the American Society of Hand Therapists guidelines, and Method B, following the National Health and Nutrition Examination Survey guidelines. To analyse HGS, we used the maximal value obtained from either two or three repetitions of the dominant hand or four or six repetitions of both hands.

RESULTS

We included 497 patients (326 men and 171 women, median age: 58 years). The maximal HGS values, measured with Method B, were significantly higher than those measured by Method A in both men and women, despite repetitions (all P < 0.05). The maximum HGS values were significantly different across the repetition groups, regardless of measurement protocols and sex (all P < 0.01). The protocol-induced differences in maximal HGS values might be clinically meaningful in over 60% of men and 40% of women despite repetitions. The repetition-induced difference was only clinically significant in 4.3-17.8% of men and 4.1-14.6% of women. To identify HGS weakness, using Method A (six repetitions) as the 'gold' standard, the other protocols demonstrated an overall accuracy of 0.923-0.997 in men and 0.965-1 in women. To identify HGS asymmetry, using Method A (six repetitions) as the 'gold' standard, Method B (six repetitions) demonstrated a diagnostic accuracy of 0.972 in men and 0.971 in women. Method A (four repetitions) showed a diagnostic accuracy of 0.837 in men and 0.825 in women, while Method B (four repetitions) showed a diagnostic accuracy of 0.825 in men and 0.807 in women.

CONCLUSIONS

Both measurement protocols and repetitions significantly affect the maximal HGS values. The identification of HGS weakness is not significantly affected by either protocols or repetitions, while the identification of HGS asymmetry may be affected by different repetitions but not protocols.

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.

Minimalist Training: Is Lower Dosage or Intensity Resistance Training Effective to Improve Physical Fitness? A Narrative Review

BACKGROUND

Findings from original research, systematic reviews, and meta-analyses have demonstrated the effectiveness of resistance training (RT) on markers of performance and health. However, the literature is inconsistent with regards to the dosage effects (frequency, intensity, time, type) of RT to maximize training-induced improvements. This is most likely due to moderating factors such as age, sex, and training status. Moreover, individuals with limited time to exercise or who lack motivation to perform RT are interested in the least amount of RT to improve physical fitness.

OBJECTIVES

The objective of this review was to investigate and identify lower than typically recommended RT dosages (i.e., shorter durations, lower volumes, and intensity activities) that can improve fitness components such as muscle strength and endurance for sedentary individuals or beginners not meeting the minimal recommendation of exercise.

METHODS

Due to the broad research question involving different RT types, cohorts, and outcome measures (i.e., high heterogeneity), a narrative review was selected instead of a systematic meta-analysis approach.

RESULTS

It seems that one weekly RT session is sufficient to induce strength gains in RT beginners with < 3 sets and loads below 50% of one-repetition maximum (1RM). With regards to the number of repetitions, the literature is controversial and some authors report that repetition to failure is key to achieve optimal adaptations, while other authors report similar adaptations with fewer repetitions. Additionally, higher intensity or heavier loads tend to provide superior results. With regards to the RT type, multi-joint exercises induce similar or even larger effects than single-joint exercises.

CONCLUSION

The least amount of RT that can be performed to improve physical fitness for beginners for at least the first 12 weeks is one weekly session at intensities below 50% 1RM, with < 3 sets per multi-joint exercise.

Musculoskeletal fitness: relative handgrip strength and vertical jump power from 10 to 18 years old

Background

There is an increasing consensus on the relevance of musculoskeletal fitness for health throughout the life cycle, requiring evaluation approaches and description of results capable of characterizing different age groups and body sizes. This study aimed to describe the musculoskeletal fitness of young Portuguese people aged 10-18 through handgrip strength (HGS) and vertical jump power (VJP) and investigate differences between the sexes.

Methods

The sample included 736 participants (359 girls recruited from schools. HGS (kg) was assessed using a handheld dynamometer, and VJP (W) was assessed using a force platform; both measurements were standardized for body mass.

Results

Higher HGS and VJP were observed in boys than in girls from 13 years old (13 years: p ≤ 0.05; 14-18 years: p ≤ 0.001), with no significant differences before this age. The percentile distributions of HGS and VJP are described for each sex using the lambda, mu, sigma (LMS) method. The pattern of development of these variables as a function of age is presented.

Conclusions

Handgrip strength and vertical jump power show differences between the sexes from 13 years of age and similar trajectories to populations in other countries in the same age group.

Low handgrip strength is associated with worse functional outcomes in long COVID

The diagnosis of long COVID is troublesome, even when functional limitations are present. Dynapenia is the loss of muscle strength and power production that is not caused by neurologic or muscular diseases, being mostly associated with changes in neurologic function and/or the intrinsic force-generating properties of skeletal muscle, which altogether, may partially explain the limitations seen in long COVID. This study aimed to identify the distribution and possible associations of dynapenia with functional assessments in patients with long COVID. A total of 113 patients with COVID-19 were evaluated by functional assessment 120 days post-acute severe disease. Body composition, respiratory muscle strength, spirometry, six-minute walk test (6MWT, meters), and hand-grip strength (HGS, Kilogram-force) were assessed. Dynapenia was defined as HGS < 30 Kgf (men), and < 20 Kgf (women). Twenty-five (22%) participants were dynapenic, presenting lower muscle mass (p < 0.001), worse forced expiratory volume in the first second (FEV1) (p = 0.0001), lower forced vital capacity (p < 0.001), and inspiratory (p = 0.007) and expiratory (p = 0.002) peek pressures, as well as worse 6MWT performance (p < 0.001). Dynapenia, independently of age, was associated with worse FEV1, maximal expiratory pressure (MEP), and 6MWT, (p < 0.001) outcomes. Patients with dynapenia had higher intensive care unit (ICU) admission rates (p = 0.01) and need for invasive mechanical ventilation (p = 0.007) during hospitalization. The HGS is a simple, reliable, and low-cost measurement that can be performed in outpatient clinics in low- and middle-income countries. Thus, HGS may be used as a proxy indicator of functional impairment in this population.

Moderating role of 1-minute abdominal test in the relationship between cardiometabolic risk factors and adiponectin concentration in adolescents

BACKGROUND

Adiponectin is an anti-inflammatory cytokine secreted by adipose tissue, has been associated with adiposity and cardiometabolic risk, and has controversial results with muscular fitness. The aim of this study was to analyze the interaction of 1-minute abdominal test in the relationship between adiposity, body composition, cardiometabolic risk and adiponectin concentration in adolescents.

METHODS

This is a cross-sectional study conducted with 62 adolescents of both sexes, aged 11 to 16 years, approved by the Ethics Committee of Research in Humans (CAEE: 62963916.0.0000.5223). Body mass, height, abdominal circumference (AC), waist circumference (WC), fat mass (FM), fat-free mass (FFM), high density lipoprotein (HDL-c), low density lipoprotein (LDL-c), triglycerides (TG), adiponectin, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP), 1-minute abdominal test (ABD) were measured. Body mass index (BMI), z-score BMI (BMI-z), triponderal mass index (TMI), and waist-to-height ratio (WHtR) were calculated. The macro PROCESS for SPSS v.24.0 was used for moderation analyses, with linear regression models.

RESULTS

Inverse interactions were found for adiposity (BMI, BMI-z, TMI, AC, WC, WHtR), body composition (FM, FFM) and CMRF (SBP, DBP, MBP, TG) versus 1-minute abdominal test with adiponectin concentration, demonstrating that abdominal test is a moderator in these relationships.

CONCLUSION

We conclude that 1-minute abdominal test may play an important role in the relationship between obesity and cardiometabolic risk. We found that muscular fitness can confer a protective effect on adolescents with high levels of abdominal test.

Investigation of cardiopulmonary parameters, motor development and muscle strength in children with Down syndrome with and without congenital heart disease

BACKGROUND

Children with Down syndrome (DS) frequently have concomitant clinical problems. There are no studies in the literature evaluating gross motor development and handgrip strength in the presence of congenital heart disease (CHD), which is one of the most common comorbidities in population with DS. The aim of this study was to compare cardiopulmonary parameters, gross motor development and handgrip strength in children with DS with and without CHD.

METHODS

A total of 28 children with DS (14 with CHD and 14 without CHD) were evaluated. Demographic data and cardiopulmonary parameters were recorded. Gross motor development and handgrip strength were assessed.

RESULTS

Children with DS and CHD had lower GMFM-88 scores and right handgrip strength and higher Wang respiratory score than children with DS and no CHD (P < 0.05). GMFM-88 scores were moderately correlated with resting oxygen saturation (r = 0.46, P = 0.01) and right handgrip strength (r = 0.67, P < 0.001).

CONCLUSIONS

Peripheral muscle strength and oxygen saturation may be factors affecting gross motor development in children with DS. From this point of view, evaluating cardiopulmonary parameters, motor development and handgrip strength in children with DS and CHD is important to identify risks, provide early intervention and support development.

The association of adolescent fitness with cardiometabolic diseases in late adulthood: A 45-year longitudinal study

OBJECTIVES

The aim of this study was to examine the associations of adolescent cardiorespiratory fitness (CRF), muscular fitness (MF), and speed-agility fitness (SA) with middle-aged cardiometabolic disease risk and explore sex differences.

METHODS

This 45-year prospective cohort study examined the associations between objectively measured fitness at adolescence (12-19 years) and physician-ascertained diabetes mellitus, elevated blood pressure (BP), and coronary heart disease reported either in early (37-44 years) or late (57-64 years) middle age, and self-measurement of waist circumference (WC) in late middle age. Fitness measurements for healthy adolescents in baseline included CRF (1.5 km [girls] and 2 km [boys] run), MF (standing broad jump, sit-ups, pull-ups [boys], and flexed-arm hang [girls]), and SA (50 m dash and 4 × 10 m shuttle run). Logistic regression and general linear models were adjusted for baseline age, sex, and body mass index (BMI), involving data from baseline and at least one follow-up measurement (N up to 1358, 47% males).

RESULTS

Adolescent CRF was inversely, and regardless of adiposity, associated with middle age accumulated burden of cardiometabolic conditions in the whole sample (N = 562, ß = -0.10, 95% confidence intervals [CI] [-0.18, -0.03], p = 0.006), and elevated BP in females (N = 256, OR = 0.71, 95% CI [0.51, 0.91]). Overall, we observed stronger associations in females than in males. An inverse association of adolescent MF and SA with middle-aged WC was observed, but it did not show as consistent associations as with CRF.

CONCLUSIONS

In this study, adolescent fitness, particularly CRF, was inversely associated with the burden of cardiometabolic conditions up to 45 years. Promotion of fitness in youth may be beneficial in preventing adulthood cardiometabolic diseases.

Physical Activity Is Associated with Physical Fitness and Executive Function among School Children in the Jiangxi Region of China

Previous studies have suggested that a positive relationship exists between physical activity (PA), physical fitness, and cognitive function in children and adolescents. However, research remains limited on the relationship among these three variables in Chinese individuals not living in big cities or specific regions. Therefore, this study investigated the association of PA with physical fitness and cognitive function (specifically, executive function) among 1100 children aged 9-12 years living in the Jiangxi region of China. Participants' PA levels were measured using the PA questionnaire for older children. Physical fitness was assessed based on cardiorespiratory endurance, muscle strength, muscular endurance, flexibility, and body mass index (BMI). Executive function was assessed using the Behavior Rating in Inventory of Executive Function questionnaire. Data were analyzed using one-way analyses of variance, Scheffé tests, one-way analyses of covariance, and Pearson's correlation coefficients. The results showed that PA is significantly associated (p < 0.01) with cardiorespiratory endurance (r = 0.460), muscular endurance (r = 0.270), muscle strength (r = 0.190), BMI (r = -0.114), and executive function (r = -0.140). Moreover, all components of physical fitness and executive function differed significantly based on PA level, with and without age and sex as covariates (p < 0.05). Overall, our results highlight the importance of higher PA levels during childhood to improve physical fitness and cognitive function. Including the goal of improving health-related fitness factors, such as cardiorespiratory endurance and muscle strength, is particularly important in PA programs for children.

Influence of physical fitness components on personality factors and risk perception of children and adolescents: a cross-sectional study

OBJECTIVES

To examine the associations of cardiorespiratory fitness (VO2 max) and muscular strength with indicators related to the risk scale, such as perceived competence, sensation seeking, competitiveness, risk taking and risk perception in sports.

DESIGN

Cross-sectional study.

SETTING

High schools from the Region of Murcia (Spain).

PARTICIPANTS

Three-hundred-and-seventeen adolescents participated (mean age: 13.69±1.2 years old).

PRIMARY AND SECONDARY OUTCOME MEASURES

Body mass, body height, Course-Navette test, upper limb strength and psychoeducational factors that determine the propensity towards sports accidents in school children, the Sports Accident Propensity Scale were evaluated. It was performance t-test for independent samples, stepwise multiple linear regression models and a multiple mediation analysis.

RESULTS

The analysis showed significant differences with respect to sex in height, VO2 max, handgrip strength and in all factors of the questionnaire (p=0.02-<0.01). Adolescents who presented greater VO2 max, strength in the handgrip test and age showed a higher score in factors 1 and 3. Higher scores in factor 2 were associated with better VO2 max and strength in handgrip test. Youngers and better values of strength in the handgrip showed higher score in factors 4 and 5. The mediation analysis with two mediating variables (handgrip strength and VO2 max) showed a significant indirect effect. When handgrip strength and VO2 max were included in the equations, the association between sex and each factor ceased to be significant.

CONCLUSION

This study highlights the potential benefits of muscular strength (handgrip) and VO2 max in the perceived risk scale, and the variable of age on this.

TRIAL REGISTRATION NUMBER

Clinical trial: NCT05544370 (pre-results).

Using Powerlifting Athletes to Determine Strength Adaptations Across Ages in Males and Females: A Longitudinal Growth Modelling Approach

INTRODUCTION

Several retrospective studies of strength sport athletes have reported strength adaptations over months to years; however, such adaptations are not linear.

METHODS

We explored changes in strength over time in a large, retrospective sample of powerlifting (PL) athletes. Specifically, we examined the rate and magnitude of strength adaptation based on age category and weight class for PL competition total, and the squat, bench press, and deadlift, respectively. Mixed effects growth modelling was performed for each operationalised performance outcome (squat, bench press, deadlift, and total) as the dependent variables, with outcomes presented on both the raw, untransformed time scale and on the common logarithmic scale. Additionally, the fitted values were rescaled as a percentage.

RESULTS

Collectively, the greatest strength gains were in the earliest phase of PL participation (~ 7.5-12.5% increase in the first year, and up to an ~ 20% increase after 10 years). Females tended to display faster progression, possibly because of lower baseline strength. Additionally, female Masters 3 and 4 athletes (> 59 years) still displayed ~ 2.5-5.0% strength improvement, but a slight strength loss was observed in Masters 4 (> 69 years) males (~ 0.35%/year).

CONCLUSION

Although directly applicable to PL, these findings provide population-level support for the role of consistent and continued strength training to improve strength across the age span and, importantly, to mitigate, or at least largely attenuate age-related declines in strength compared to established general population norms. This information should be used to encourage participation in strength sports, resistance training more generally, and to support future public health messaging.

Primary school children's health and its association with physical fitness development and health-related factors

The health status (HS) of children is influenced by a variety of factors, including physical fitness (PF) or social and environmental characteristics. We present a 4-year longitudinal study carried out with 263 primary school children. PF was assessed yearly using the German Motor Performance Test 6-18. Demographic data, leisure time behavior and socioeconomic factors were collected using questionnaires for children and parents. Based on parents' ratings in year 4, children were categorized as either "very good health status" (VGHS) or "good health status or below" (GHSB). Children with VGHS (73%) showed a larger improvement of global PF (p < 0.001), a significantly higher proportion of being/playing outside (p < 0.001), significantly lower proportions of overweight (p < 0.001), of media availability in the bedroom (p = 0.011) and of daily media consumption > 2 h (p = 0.033) compared to children with GHSB. Regarding socio-economic factors, children with VGHS revealed significantly fewer parents with lower education (p = 0.002), lower physical activity levels (p = 0.030) and lower migration background (p < 0.001). Physical fitness (p = 0.019) and outdoors exercising (p = 0.050) were the only variables to provide significantly higher chances of perceiving one's own health as very good when tested within a complex model including all the variables studied in this work. Considering the little focus on PF in the current Austrian physical education curriculum and the favorable environmental features of the Tyrolean region, more emphasis should be given to promoting didactical and pedagogical approaches that allow schoolers to be active in the nature.

Establishing thresholds of handgrip strength based on mortality using machine learning in a prospective cohort of Chinese population

Background

The relative prognostic importance of handgrip strength (HGS) in comparison with other risk factors for mortality remains to be further clarified, and thresholds used for best identify high-risk individuals in health screening are not yet established. Using machine learning and nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS), the study aimed to investigate the prognostic importance of HGS and establish sex-specific thresholds for health screening.

Methods

A total of 6,762 participants from CHARLS were enrolled. A random forest model was built using 30 variables with all-cause mortality as outcome. SHapley Additive exPlanation values were applied to explain the model. Cox proportional hazard models and Harrell's C index change were used to validate the clinical importance of the thresholds.

Results

Among the participants, 3,102 (45.9%) were men, and 622 (9.1%) case of death were documented follow-up period of 6.78 years. The random forest model identified HGS as the fifth important prognostic variable, with thresholds for identifying high-risk individuals were < 32 kg in men and < 19 kg in women. Low HGS were associated with all-cause mortality [HR (95% CI): 1.77 (1.49-2.11), p < 0.001]. The addition of HGS thresholds improved the predictive ability of an established office-based risk score (C-index change: 0.022, p < 0.001).

Conclusion

On the basis of our thresholds, low HGS predicted all-cause mortality better than other risk factors and improved prediction of a traditional office-based risk score. These results reinforced the clinical utility of measurement of HGS in health screening.

Short-Term Impact of Exercise Fitness Testing in a Pediatric Metabolic and Obesity Clinic: Initiative to Improve Health Care Quality

This 2-phase pilot initiative determined whether (1) fitness testing could feasibly be implemented in pediatric practice, and (2) short-term changes in fitness and body mass index occur with Specific, Measurable, Attainable, Relevant, and Time-based (SMART) goals. Phase 1 (N = 580), clinic feasibility: evidence-based prognostic tests were successfully performed to measure cardiorespiratory fitness (CRF; 3-minute bench step), strength (handgrip dynamometry), and flexibility (sit-and-reach distance). Mean CRF percentile was 58.1 (worst >95 percentile, best <5 percentile), strength percentile was 73.5, and flexibility was 42.3 (worst <5 percentile, best >95 percentile). Phase 2, goal setting and follow-up: SMART fitness goals were developed. In phase 2, patients demonstrated 11.9% and 12.4% improvements in CRF and strength percentiles (P < .05) respectively. All patients who were assigned a strength goal improved handgrip strength. Body mass index percentile changes were not different by SMART goal target. Fitness testing was feasible and successfully improved CRF and strength in children at high risk of metabolic complications and future disability.

Impact of the COVID-19 lockdown on physical fitness among college women living in China

PURPOSES

The purpose of this study was to evaluate the effects of the COVID-19 lockdown on physical fitness among college women living in China and to explore how fitness changed with different physical conditions.

METHODS

We performed repeated measures of BMI, 800 m running and sit-up performance assessment on college women from one university in China pre and post the COVID-19 lockdown. A total of 3658 (age 19.15 ± 1.08 yr.) college women who completed the same assessment pre and post the COVID-19 lockdown were included in the analysis. We analyzed the data using one way ANOVA and paired-samples t-test.

RESULTS

Due to the COVID-19 lockdown, the result shows a significant increase in BMI by 2.91% (95% CI =0.33, 0.40) and a significant decline in 800 m running and sit-up by 7.97% (95% CI =0.69, 0.77) and 4.91% (95% CI = -0.27, -0.19), respectively. College women in the highest quartile level of physical condition (Quartile 4) had more decreases than college women in the lowest quartile level (Quartile 1). Their BMI level was increased by 3.69% and 0.98% in college women in Quartile 4 and Quartile 1, respectively. Their performance of 800 m running was decreased by 9.32% and 7.37% in college women in Quartile 4 and Quartile 1, respectively. Their performance of sit-up was decreased by 13.88% in college women in Quartile 4 while it increased by 10.91% in college women in Quartile 1, respectively.

CONCLUSIONS

The COVID-19 lockdown might increase the BMI level and decrease 800 m running and sit-up performance among college women living in China. The decrease for college women in higher quartile level of physical condition (Quartile 4) were more seriously while college women in lower quartile level of physical condition (Quartile 1) were modest.

Genetic and Environmental Factors and Cardiovascular Disease Risk in Adolescents

Importance

Cardiovascular risk factors in youth have been associated with future cardiovascular disease (CVD), but conventional observational studies are vulnerable to genetic and environmental confounding.

Objective

To examine the role of genetic and environmental factors shared by full siblings in the association of adolescent cardiovascular risk factors with future CVD.

Design, Setting, and Participants

This is a nationwide cohort study with full sibling comparisons. All men who underwent mandatory military conscription examinations in Sweden between 1972 and 1995 were followed up until December 31, 2016. Data analysis was performed from May 1 to November 10, 2022.

Exposures

Body mass index (BMI), cardiorespiratory fitness, blood pressure, handgrip strength, and a combined risk z score in late adolescence.

Main Outcomes and Measures

The primary outcome was fatal or nonfatal CVD, as recorded in the National Inpatient Register or the Cause of Death Register before 2017.

Results

A total of 1 138 833 men (mean [SD] age, 18.3 [0.8] years), of whom 463 995 were full brothers, were followed up for a median (IQR) of 32.1 (26.7-37.7) years, during which 48 606 experienced a CVD outcome (18 598 among full brothers). All risk factors were associated with CVD, but the effect of controlling for unobserved genetic and environmental factors shared by full siblings varied. In the sibling analysis, hazard ratios for CVD (top vs bottom decile) were 2.10 (95% CI, 1.90-2.32) for BMI, 0.77 (95% CI, 0.68-0.88) for cardiorespiratory fitness, 1.45 (95% CI, 1.32-1.60) for systolic blood pressure, 0.90 (95% CI, 0.82-0.99) for handgrip strength, and 2.19 (95% CI, 1.96-2.46) for the combined z score. The percentage attenuation in these hazard ratios in the sibling vs total cohort analysis ranged from 1.1% for handgrip strength to 40.0% for cardiorespiratory fitness. Consequently, in the sibling analysis, the difference in cumulative CVD incidence at age 60 years (top vs bottom decile) was 7.2% (95% CI, 5.9%-8.6%) for BMI and 1.8% (95% CI, 1.0%-2.5%) for cardiorespiratory fitness. Similarly, in the sibling analysis, hypothetically shifting everyone in the worst deciles of BMI to the middle decile would prevent 14.9% of CVD at age 60 years, whereas the corresponding number for cardiorespiratory fitness was 5.3%.

Conclusions and Relevance

In this Swedish national cohort study, cardiovascular risk factors in late adolescence, especially a high BMI, were important targets for CVD prevention, independently of unobserved genetic and environmental factors shared by full siblings. However, the role of adolescent cardiorespiratory fitness in CVD may have been overstated by conventional observational studies.

Can Moving More and Sitting Less Improve the Academic Engagement of Adolescents?- A Study Based on Junior High School Students in Shanghai, China

Purpose

The purpose of this study was to examine the relationships between academic engagement and moderate-to-vigorous physical activity (MVPA), muscle-strengthening exercise (MSE) and sedentary behavior (SB) among adolescents, so as to provide evidence from the perspective of exercising for students to learn efficiently, teachers to improve classroom teaching, and schools to improve educational quality.

Methods

A questionnaire survey was conducted in 12 junior high schools in Shanghai, China, which were selected by a multi-stage stratified cluster sampling method. Then, with the valid data of 2078 students collected from the survey. A data analysis was performed using SPSS Statistics 26.0. Multiple linear regression models were adopted to analyze the factors affecting adolescent academic engagement and to determine whether MVPA, MSE, and SB play roles in it.

Results

(1) The differences in academic engagement depended on the exercise adherence to the recommended amount of MVPA, MSE, and screen-based SB. (2) In terms of the three independent variables of total time, MSE (β = 0.206) and MVPA (β = 0.175) showed a significant positive correlation with academic engagement, while SB (β = -0.155) was negatively correlated with academic engagement. (3) From the linear regression model of eight combination groups divided by the exercise adherence to the recommended amount of MVPA, MSE and SB, the group that met none of the recommendations (β = -0.235) showed a significant negative effect on academic engagement, while the groups that met any two or all three of the recommendations demonstrated strong positive correlations with academic engagement (P < 0.001).

Conclusion

Increasing adolescents' muscle-strengthening exercise and moderate-to-vigorous physical activity and reducing sedentary behavior can effectively promote academic engagement. Therefore, adolescents are suggested to reach the recommended amounts of physical activity, muscle-strengthening exercise, and sedentary behavior so as to improve academic engagement more effectively.

Prospective associations between hand grip strength and subsequent depressive symptoms in men and women aged 50 years and older: insights from the Survey of Health, Aging, and Retirement in Europe

Introduction

In previous cross-sectional and longitudinal studies, depressive symptoms have been associated with lower hand grip strength (HGS), which is a convenient measure of overall muscular strength and serves as a marker of poor health. Most studies have considered low sample sizes or highly selective patient cohorts.

Methods

We studied the association between depressive symptoms (EURO-D) and HGS in three waves from the cross-national panel dataset Survey of Health, Aging, and Retirement in Europe (SHARE). Linear regressions and Generalized Estimating Equations (GEE) were conducted to determine factors associated with depressive symptoms and investigate whether HGS predicts future depressive symptoms.

Results

Cross-sectional HGS explained 7.0% (Wave 4), 5.7% (Wave 5), and 6.4% (Wave 6) of the EURO-D variance. In the GEE, we analyzed people without depression in Wave 4 (N = 39,572). HGS predicted future EURO-D (B = -0.21, OR = 0.979, 95%CI (0.979, 0.980), p < 0.001) and remained a significant predictor of future depressive symptoms after adjustment for age, sex, psychosocial and physical covariates.

Discussion

Muscle strength is a known marker for physical health, but a relation with mental health has also been proposed previously. This study confirmed the link between HGS and depressive symptoms in men and women aged ≥50 years in a large longitudinal dataset. Further research is required to understand the mechanisms behind this link to determine whether HGS can serve as a specific marker of depressive symptomology, or whether they coexist due to common underlying disease processes.

Temporal trends in the physical fitness of Hong Kong children aged 6-12 years between 2003-04 and 2015-16

Low physical fitness in childhood is linked with poor health now and in later life. This study estimated temporal trends in physical fitness for Hong Kong children aged 6-12 years from 2003-04 to 2015-16. Objectively measured body size and physical fitness data for 27,513 children were obtained from four population-representative surveys of Hong Kong primary school students. Temporal trends in means were estimated by population-weighted linear regression. Trends in distributional characteristics were visually described. Overall, there was a small increase in mean height (effect size (ES) = 0.20 (95%CI: 0.13, 0.28)), with a negligible increase (ES < 0.2) in mean body mass. When adjusted for trends in age, gender, and body size, there was a small decline in sit-and-reach performance (ES = -0.43 (95%CI: -0.43, -0.42)), a small improvement in 9-min run/walk performance (9-to-12-year-olds, ES = 0.26 (95%CI: 0.26, 0.27)), with negligible declines in handgrip strength, 6-min run/walk (6-to 8-year-olds), and sit-ups performance. Temporal trends were not always uniform across the population distribution, with declines in run/walk, sit-ups, and sit-and-reach performance generally largest in children with low fitness. Increased national health promotion strategies that address culturally specific factors are encouraged to further improve the existing trends, especially for children with low fitness.

Temporal Trends in the Physical Fitness of Hong Kong Adolescents Between 1998 and 2015

Low physical fitness in adolescence is linked with increased cardiometabolic risk and early all-cause mortality. This study aimed to estimate temporal trends in the physical fitness of Hong Kong adolescents aged 12-17 years between 1998 and 2015. Physical fitness (9-min run/walk, sit-ups, push-ups, and sit-and-reach) and body size data in a total of 28,059 adolescents tested across five population-representative surveys of Hong Kong secondary school pupils, were reported. Temporal trends in means were estimated at the gender-age level by best-fitting sample-weighted linear regression, with national trends estimated by a post-stratified population-weighting procedure. Overall, there were small declines in 9-min run/walk (effect size (ES)=-0.29 (95%CI: -0.32, -0.26)) and sit-ups performance (ES=-0.24 (95%CI: -0.27, -0.21)), with negligible changes in push-ups and sit-and-reach performance. There were small concurrent increases in both mean height and body mass, with a negligible increase in sum of skinfolds. Trends in mean physical fitness and body size/were not always uniform across the population distribution. The small declines in mean 9-min run/walk and sit-ups performance for Hong Kong adolescents are suggestive of corresponding declines in cardiorespiratory fitness and abdominal/core endurance, respectively. Increased national health promotion strategies are required to improve existing trends.

Associations between combinations of 24-h movement behaviors and physical fitness among Chinese adolescents: Sex and age disparities

OBJECTIVE

To analyze the relationship between 24-h movement behaviors and adolescents' physical fitness, with sex difference and age disparity explored specifically.

METHODS

A total of 135 852 Chinese adolescents aged 13-22 years were included in this cross-sectional study. Self-reported 24-h movement behavioral times, including moderate to vigorous physical activity (MVPA), recreational screen, and sleep, were identified as meeting guidelines based on Canadian recommendations. Physical fitness indicator (PFI) was calculated through sex- and age-specific z scores of body mass index, forced vital capacity, 50 m dash, sit-and-reach, standing long jump, body muscle strength, and endurance running, and then classified as: low level (<20th), middle level (20th-80th), and high level (>80th). Mixed effect logistic regression was applied to analyze the association, and interaction terms were constructed to prove the sex and age disparities.

RESULTS

Only 12.4% of adolescents aged 13-22 years met all three recommendations. The number of meeting guidelines exhibited a typical dose-response relationship with high level PFI (OR = 1.22 [95% CI: 1.19-1.25]), and in detail, meeting MVPA + recreational screen (OR = 2.29 [95% CI: 2.09-2.51]) or MVPA-only (OR = 2.16 [95% CI: 1.93-2.41]) guidelines were better associated with high-level PFI. Besides, meeting MVPA-only guideline was proved with stronger association with high-level PFI for boys (p-interaction = 0.005). The dose-response relationship in boys of the number of guidelines met with PFI was stronger in 19- to 22-year-olds (p-interaction <0.001) and 16- to 18-year-olds (p-interaction = 0.001) than that in 13- to 15-year-olds.

CONCLUSION

The prevalence of meeting 24-h movement behaviors guidelines among Chinese adolescents aged 13-22 years was relatively low. It was associated with adolescents' physical fitness, with meeting MVPA + recreational screen or MVPA-only guidelines bringing greater benefits, and sex difference and age disparity existing.

Handgrip strength associates with effort-dependent lung function measures among adolescents with and without asthma

Studies have shown association between handgrip strength (HGS) and FEV1, but the importance of this in relation to asthma pathophysiology and diagnostics remains unclear. We investigated the relationship between HGS and lung function metrics and its role in diagnosing asthma. We included 330 participants (mean age: 17.7 years, males: 48.7%) from the COPSAC2000 cohort and analyzed associations between HGS, asthma status, spirometry measures (FEV1, FVC, MMEF, FEV1/FVC), airway resistance (sRaw), methacholine reactivity (PD20) and airway inflammation (FeNO). Finally, we investigated whether HGS improved FEV1 prediction and classification of asthma status. HGS was only associated with forced flows, i.e., positive association with FEV1 and FVC for both sexes in models adjusted for age, height, and weight (P < 0.023). HGS improved adjusted R2-values for FEV1 prediction models by 2-5% (P < 0.009) but did not improve classification of asthma status (P > 0.703). In conclusion, HGS was associated with the effort-dependent measures FEV1 and FVC, but not with airway resistance, reactivity, inflammation or asthma status in our cohort of particularly healthy adolescents, which suggests that the observed associations are not asthma specific. However, HGS improved the accuracy of FEV1 estimation, which warrants further investigation to reveal the potential of HGS in asthma diagnostics.

Handgrip Strength and Healthspan: Impact of Sports During the Developmental Period on Handgrip Strength (Juntendo Fitness Plus Study)

Handgrip strength as a biomarker is being studied as a factor in predicting disease onset. However, the effect of improving handgrip strength through physical exercises, such as sports during the developmental period, on disease prevention has yet to be fully elucidated. The Juntendo Fitness Plus (J-Fit Plus) Study is a unique database of anthropometric and physical fitness measurements with over 50 years of accumulated data. It has the potential to explore the effects of sports on the association between handgrip strength and morbidity/mortality. We first outline previous studies on the impact of physical exercise interventions on handgrip strength, separated into adulthood and developmental period. We then introduced a unique effort to investigate the effects of sports using the J-Fit Plus Study database and describe the challenges of finally elucidating the impact of exercise on the association between handgrip strength and health status.

Hand grip strength in venous thromboembolism: risk of recurrence and mortality

Background

There is limited information on the relationship between muscle strength and recurrence and mortality after incident venous thromboembolism (VTE).

Objectives

To investigate whether weak hand grip strength (HGS) was associated with risk of recurrence and mortality in patients with VTE recruited from the general population.

Methods

Participants from the Tromsø Study with a first-time VTE (n = 545) were included, and all VTE recurrences and deaths among the participants were recorded in the period 1994 to 2020. Weak HGS was defined as lowest 25th percentile of the general population, and incidence rates for VTE recurrence and mortality according to weak vs normal (>25th percentile) HGS, with 95% CIs, were estimated.

Results

There were 90 recurrences and 350 deaths during a median of 3.7 years of follow-up. The fully adjusted hazard ratio (HR) for overall VTE recurrence for those with weak HGS vs those with normal HGS was 2.02 (95% CI, 1.23-3.30). The corresponding HRs for recurrence were 2.22 (95% CI, 1.18-4.17) in patients with a first deep vein thrombosis and 1.60 (95% CI, 0.72-3.57) in patients with a first pulmonary embolism. The cumulative 1-year survival was 74.9% and 77.8% in those with weak and normal HGS, respectively. For overall mortality after incident VTE, the fully adjusted HR for those with weak HGS was 1.34 (95% CI, 1.04-1.72).

Conclusion

Weak HGS was associated with an increased risk of recurrent VTE, and the association appeared to be particularly pronounced after incident deep vein thrombosis. There was a slightly lower survival probability among those with weak HGS than among those with normal HGS.

Analysis of Self-Perceived Physical Fitness of Physical Education Students in Public Schools in Extremadura (Spain)

Adolescence is a stage of crucial physiological and psychological changes within the individual's life cycle, where fitness work is important. With self-perception being crucial in relation to adolescent health and well-being, a positive perception of fitness is directly related to increased practice or higher level of physical activity (PA). Thus, the aims were: (1) to analyze, with the Visual Analogue Fitness Perception Scale for Adolescents (FP VAS A), the self-perceived physical fitness (PF) of high school students, (2) to investigate if there are differences according to sex and school location, and (3) to study the correlations between the items of the FP VAS A with age and body mass index (BMI). For this purpose, a cross-sectional study was designed with a total of 961 participants, 48.8% boys and 51.2% girls in secondary education, where 31.9% studied in rural schools and 68.1% in urban schools. The FP VAS A scale was used to assess self-reported PF. Regarding the results, there were statistically significant differences between sexes (p < 0.001), with boys showing higher scores than girls in all the items of the FP VAS A scale, with the exception of global flexibility. Inverse, mean and significant correlations were established between BMI and self-perceived overall PF (r = -0.202; p < 0.001), cardiorespiratory endurance (r = -0.226; p < 0.001) and movement speed (r = -0.268; p < 0.001). Between age and self-perceived cardiorespiratory endurance (r = -0.138; p < 0.001) an inverse, mean and significant correlation was also observed. In conclusion, boys showed a better self-perception of PF than girls for all physical abilities, with the exception of flexibility. School location was not shown to influence students' self-perceived PF. In addition, most of the self-perceived PF abilities for overall fitness correlated inversely with BMI.

Are the digit ratio (2D:4D) and hand grip strength related to Parkinson disease in elderly males?

BACKGROUND

Sex hormones affect the pathogenesis of Parkinson patients and it has been suggested that gender is the most important factor in the development and progression of Parkinson's disease. Studies have shown that the second to fourth digit ratio (2D:4D) is affected by the prenatal testosterone and estrogen levels and can predict predisposition to disease. In addition, decreased muscle strength in people with Parkinson's has been repeatedly reported. Hand grip strength (HGS) is a suitable measure to evaluate the musculoskeletal system among the elderly and it is considered as an indicator of the overall strength of the body. This study aimed at investigating the relationship between Parkinson's disease and HGS and 2D:4D ratio.

METHODS

In this study 117 elderly men with Parkinson disease (mean age of 61.66 ± 11.28 years) and 156 healthy control subjects (mean age of 61.86 ± 6.29 years) participated. After determining the level of disability of Parkinson patients by a neurologist (level of disability in the range of 1-4), anthropometric indices (height, weight, length of the second and fourth fingers) and maximum HGS were measured.

RESULTS

Although 2D:4D ratios (right and left hand) of male patients with Parkinson's disease were higher than those of healthy males, this difference was not statistically significant (P = 0.12, P = 0.40; respectively). Conversely, HGS for the right and left hands of Parkinson patients were significantly lower than those of healthy males (P = 0.02, P = 0.03; respectively). The results showed a significant negative relationship between Parkinson disease and the right and left HGS (R = -0.16, P = 0.005; R = -0.17, P = 0.003; respectively). Parkinson disease had no significant relationship with 2D:4D of the right hand, left hand, mean finger ratio and D_R-L 2D:4D (P > 0.05). The regression results showed that the right and left HGS were not able to predict Parkinson disease (P = 0.25, P = 0.16; respectively).

CONCLUSION

We concluded that HGS was negatively associated with the Parkinson disease, but conversely, 2D:4D may not be a valuable biomarker of elevated risk of Parkinson in elderly males.

Athletes in sporting events with upper-body gripping movements have greater handgrip strength than those in sporting events that prioritize the lower body

OBJECTIVE

Evidence suggests that acquiring a high level of handgrip strength early in life and maintaining that strength throughout life may be important for health. In addition, it is thought that sports activities performed during the developmental period are effective in improving handgrip strength, but it is unknown what types of sports are more effective. As a first step, we conducted a cross-sectional study to compare handgrip strength across different sports (upper-body gripping sports vs. lower body) in early adulthood.

METHODS

We used the Juntendo Fitness Plus Study data from 1973 to 2018 and selected two types of sporting events with matching physiques (soccer, baseball, and kendo) but different degrees of gripping. Data on 7344 male first-year sports university students included 1127 soccer, 297 Kendo, and 698 baseball players.

RESULTS

Those in the lower body-only (soccer) sports had -3.78 (95% CI: -4.27, -3.29) kg lower handgrip strength than those in the lower + upper (kendo and baseball). Comparing each individual sport found that each sport was different from each other with Kendo > Baseball > Soccer (between each sport, p < .001). In addition, the difference between sports has become greater across time.

CONCLUSIONS

In early adulthood, handgrip strength is greatest in those participating in sports with upper-body movements compared to those participating in sports that mainly involved lower-body movements. The three sports we selected are natural activities that do not directly train handgrip strength. Therefore, sport may be one potential method to improve low handgrip strength in children/adolescents during the developmental period.

Analysis of secular trends in physical fitness of children and adolescents (8-18 years) from Kraków (Poland) between 2010 and 2020

OBJECTIVES

The aim of the study was to analyze the changes of the motor skills of children and adolescents from Kraków between 2010 and 2020.

METHODS

The group included 4106 children and adolescents (8-18 years of age). The analysis of changes included results of the following fitness tests: backwards overhead medicine ball throw, standing broad jump, dynamometric strength of the hand, flexibility test, as well as shuttle run (10 × 5 m).

RESULTS

A negative trend in both sexes was observed in the results of overhead medicine ball throw. The girls also had a negative intergenerational changes in the results of the shuttle run and the flexibility test. A positive secular trend was also observed in both sexes in relations to the dynamometric force of the right and left hand. In addition, the boys studied in more contemporary times showed better results in the shuttle run, compared to their peers in 2010.

CONCLUSION

The study reported a decline in overall motor performance in children and adolescents. The observed results may be related to a decrease in the level of physical activity, as well as a higher incidence of overweight and high levels of body fat in the modern population.

European fitness landscape for children and adolescents: updated reference values, fitness maps and country rankings based on nearly 8 million test results from 34 countries gathered by the FitBack network

OBJECTIVES

(1) To develop reference values for health-related fitness in European children and adolescents aged 6-18 years that are the foundation for the web-based, open-access and multilanguage fitness platform (FitBack); (2) to provide comparisons across European countries.

METHODS

This study builds on a previous large fitness reference study in European youth by (1) widening the age demographic, (2) identifying the most recent and representative country-level data and (3) including national data from existing fitness surveillance and monitoring systems. We used the Assessing Levels of PHysical Activity and fitness at population level (ALPHA) test battery as it comprises tests with the highest test-retest reliability, criterion/construct validity and health-related predictive validity: the 20 m shuttle run (cardiorespiratory fitness); handgrip strength and standing long jump (muscular strength); and body height, body mass, body mass index and waist circumference (anthropometry). Percentile values were obtained using the generalised additive models for location, scale and shape method.

RESULTS

A total of 7 966 693 test results from 34 countries (106 datasets) were used to develop sex-specific and age-specific percentile values. In addition, country-level rankings based on mean percentiles are provided for each fitness test, as well as an overall fitness ranking. Finally, an interactive fitness platform, including individual and group reporting and European fitness maps, is provided and freely available online (www.fitbackeurope.eu).

CONCLUSION

This study discusses the major implications of fitness assessment in youth from health, educational and sport perspectives, and how the FitBack reference values and interactive web-based platform contribute to it. Fitness testing can be conducted in school and/or sport settings, and the interpreted results be integrated in the healthcare systems across Europe.

The Effect of Different Physical Exercise Programs on Physical Fitness among Preschool Children: A Cluster-Randomized Controlled Trial

BACKGROUND

Preschool children are in a period of rapid physical and psychological development, and improving their level of physical fitness is important for their health. To better develop the physical fitness of preschool children, it is very important to understand the behavioral attributes that promote the physical fitness of preschool children. This study aimed to determine the effectiveness of and the differences between different physical exercise programs in improving preschool children's physical fitness.

METHODS

A total of 309 preschool children aged 4-5 years were recruited from 5 kindergartens to participate in the experiment. They were cluster-randomly allocated into five groups: basic movements (BM) group, rhythm activities (RA) group, ball games (BG) group, multiple activities (MA) group, and control (CG) group. The intervention groups received designed physical exercise programs with a duration of 30 min 3 times per week for 16 weeks. The CG group received unorganized physical activity (PA) with no interventions. The physical fitness of preschool children was measured using the PREFIT battery before and after the interventions. One-way analysis of variance, a nonparametric test; generalized linear models (GLM); and generalized linear mixed models (GLMM) were used to examine differences during the pre-experimental stage among groups and to assess the differential effects of the intervention conditions on all outcome indicators. The intervention condition models were adjusted for potential confounders (baseline test results, age, gender, height, weight, and body mass index) explaining the main outcome variance.

RESULTS

The final sample consisted of 253 participants (girls 46.3%) with an average age of 4.55 ± 0.28 years: the BG group (n = 55), the RA group (n = 52), the BM group (n = 45), the MA group (n = 44), and the CG group (n = 57). The results of the generalized linear mixed model and generalized linear model analyses indicated significant differences for all physical fitness tests between groups, except for the 20 m shuttle run test and the sit-and-reach test after the interventions. Grip strength was significantly higher in the BG and MA groups than in the BM group. The scores for standing long jump were significantly higher in the MA group than in the other groups. The scores for the 10 m shuttle run test were significantly lower in the BG and MA groups than in the CG, BM, and RA groups. The scores for skip jump were significantly lower in the BG and MA groups than in the RA group. The scores for balance beam were significantly lower in the BG and MA groups than in the RA group and significantly lower in the BG group than in the BM group. The scores for standing on one foot were significantly higher in the BG and MA groups than in the CG and RA groups and significantly higher in the BM group than in the CG group.

CONCLUSIONS

Physical exercise programs designed for preschool physical education have positive effects on the physical fitness of preschool children. Compared with the exercise programs with a single project and action form, the comprehensive exercise programs with multiple action forms can better improve the physical fitness of preschool children.

Design of a Computer Model for the Identification of Adolescent Swimmers at Risk of Low BMD

This paper aims to elaborate a decision tree for the early detection of adolescent swimmers at risk of presenting low bone mineral density (BMD), based on easily measurable fitness and performance variables. The BMD of 78 adolescent swimmers was determined using dual-energy X-ray absorptiometry (DXA) scans at the hip and subtotal body. The participants also underwent physical fitness (muscular strength, speed, and cardiovascular endurance) and swimming performance assessments. A gradient-boosting machine regression tree was built to predict the BMD of the swimmers and to further develop a simpler individual decision tree. The predicted BMD was strongly correlated with the actual BMD values obtained from the DXA (r = 0.960, p < 0.001; root mean squared error = 0.034 g/cm2). According to a simple decision tree (74% classification accuracy), swimmers with a body mass index (BMI) lower than 17 kg/m2 or a handgrip strength inferior to 43 kg with the sum of both arms could be at a higher risk of having a low BMD. Easily measurable fitness variables (BMI and handgrip strength) could be used for the early detection of adolescent swimmers who are at risk of suffering from low BMD.

Correlation of the Handgrip Strength and Body Composition Parameters in Young Judokas

Maximum isometric handgrip strength (MIHS) is a relevant parameter for judo performance and is related to health. Understanding the association between MIHS and MIHS relative (MIHSrel) and the absolute lean mass of the arm (LMarm) and the percentage of body fat (%BF) can provide important information for performance and health. The study aimed to investigate the correlation between MIHS and MIHSrel with the LMarm and the %BF of young judokas (sub-19, 15 males and 14 females). MIHS was measured using a multipurpose digital dynamometer with a load cell for computer. Body composition was measured by dual-energy X-ray absorptiometry (DXA). The correlation between MIHS, MIHSrel with LMarm and %BF was verified through Pearson's correlation, with a significance level of p < 0.05. Correlation between MIHSrel and %BF was very high only in female judokas for both arms (right, r = -0.76; left, r = -0.75). Correlations between LMarm and MIHS of the right and left arms ranged from very high to almost perfect for both sexes (r = 0.74 to 0.94). These results highlight the importance of strengthening the arms in young judokas, and controlling body fat for performance and health, especially in female judokas.

Individual and combined impact of physical fitness on health-related quality of life during adolescence: DADOS Study

The purpose of the present study was to investigate the individual and combined impact of physical fitness components at baseline on health-related quality of life (HRQoL) at 24-month follow-up in adolescents. This longitudinal research included 199 adolescents (13.9±0.3 years at baseline) from the DADOS study. Cardiorespiratory fitness was assessed using the 20-m shuttle run test. Muscular strength was assessed using the standing broad jump test. Motor competence was assessed using the 4 × 10-m shuttle run test. A physical fitness z-score was calculated as the mean of the z-scores values of each fitness test. A fitness index ranging from 0 to 3 was created according to the number of physical fitness components in which participants achieved high levels according to normative values. HRQoL was evaluated by the KIDSCREEN-10 questionnaire. Linear regression analyses showed that cardiorespiratory fitness, muscular strength, and the physical fitness z-score at baseline were individually associated with HRQoL at follow-up (β ranging from 0.123 to 0.183; all p < 0.05). Moreover, logistic regression analysis revealed that adolescents with a fitness index ≥1 at baseline were more likely to achieve high HRQoL at 24-month follow-up, compared with their peers with an index of 0 (OR ranging from 3.554 to 9.087; all p < 0.05). Our results revealed an individual and cumulative positive impact of physical fitness at baseline on HRQoL at 24-month follow-up. These findings underline the key role of promoting the enhancement of overall physical fitness components in order to improve adolescents' health and well-being.Highlights Adolescents with high levels of cardiorespiratory fitness, muscular strength and motor competence will benefit from a greater physical and mental well-being over the time.The more physical fitness components with optimal levels, the greater likelihood of reaching better HRQoL over the time.Public health authorities should focus on the promotion of multiple physical fitness components to increase adolescent's likelihood of achieving greater HRQoL over the time.

Annual changes in grip strength and skeletal muscle mass in chronic liver disease: observational study

Sarcopenia is a common complication in patients with chronic liver disease (CLD); however, the progression of sarcopenia over the course of CLD is unclear. The present study therefore determined the natural course of the progression of sarcopenia in patients with CLD and the effect of liver cirrhosis (LC) on this progression. This observational study analyzed patients with chronic hepatitis (CH) (n = 536) and LC (n = 320) who underwent evaluations of the grip strength and skeletal muscle mass of the arms, trunk, and legs for sarcopenia between 2016 and 2021. A bioelectrical impedance analysis was used to evaluate skeletal muscle mass. The annual rate of change (%/year) in two tests were compared between patients with CH and LC. The annual rates of change in grip strength and skeletal muscle of arms, trunk, and legs of patients with CH and LC were - 0.84% vs. - 2.93%, - 0.54% vs. - 1.71%, - 0.43% vs. - 1.02%, and - 0.76% vs. - 1.70% for men and - 0.12% vs. - 1.71%, - 0.66% vs. - 1.71%, - 0.49% vs. - 1.31%, and - 0.76% vs. - 1.54% for women, respectively. The progression of sarcopenia was greater in LC patients than in CH patients and that the decrease in grip strength was most prominent in the progression of sarcopenia in patients with LC.