Secular trends in health-related physical fitness in Spanish adolescents: The AVENA and HELENA Studies

Assessment of nutritional status, physical fitness and physical activity of school going adolescents (12-15 years) in Delhi

BACKGROUND

Adolescence is a distinct period that is crucial for setting the foundation for long-term health.

OBJECTIVE

To assess the nutritional status, physical fitness, and physical activity of adolescents.

METHODS

The present cross-sectional study recruited 100 adolescents purposively. Information regarding general profile and lifestyle-related factors was collected using a questionnaire. Anthropometric data such as height, weight, BMI, and body fat% were collected using appropriate equipment. Physical fitness was assessed using a battery adapted from FITNESSGRAM® and PAQ-A assessed the physical activity. Dietary intake was analysed using a 2-day 24-hour dietary recall.

RESULT

The study revealed, 19% of the participants were overweight and 6% were obese. The majority (74%) were physically inactive and 15% had high body fat %. There was lower consumption of energy, carbohydrates, iron, and calcium, than the recommendations. Also, physical activity scores were negatively associated with macronutrient intake and trunk lift (strength and flexibility) [p < 0.05]. Data showed lower physical fitness scores. BMI and hand-grip strength was positively correlated [p < 0.05]. Push Ups (endurance) and Standing Broad Jump (power) showed a negative correlation with body fat%. Tennis ball throw and PACER (cardiorespiratory fitness) were positively associated with protein intake. A multiple regression analysis significantly showed that a unit increase in cell phone usage increases body fat% by 11.64 units. Standing broad jump increases by 38.6 cm and decreases with 28.76 cm with a unit increase in playing outside and tuitions timings respectively.

CONCLUSION

Poor nutritional status, physical fitness, and physical activity were reported among adolescents. It is imperative to plan intervention strategies to improve the overall health of adolescents.

Measuring handgrip strength in school children: inter-instrument reliability between Takei and Jamar

The aim of this study was to determine inter-instrument reliability between Takei and Jamar dynamometers in school children. Fifty-six five grade participants aged eleven to twelve (n = 32 boys, n = 24 girls) performed handgrip strength test on two different occasions, with a 5-day gap between them, as test-retest. The Pearson correlation coefficient showed very large to almost perfect correlation between both devices (r = 0.76-0.91) which was graphically confirmed by Bland-Altman method. Test-retest also showed high reliability (ICC = 0.78-0.85) for Jamar and Takei. Trivial, nonsignificant differences (p > 0.05) were observed between for test-retest trials for Takei left hand (ES = 0.04), right hand (ES = 0.12) and Jamar left hand (ES = 0.15). According to the results, both the Jamar and Takei dynamometers are valid and reliable for measuring schoolchildren, and both devices may be used to assess a student's handgrip strength for this age group.

Long-term changes in physical fitness components determining the motor performance of young people studying physiotherapy in 2001-2020

The aim of the study is to assess changes in basic somatic features and motor components of physical fitness of physiotherapy students in the years 2001-2020. Hypotheses were made about the lack of a secular trend in body height and weight, the deterioration of motor efficiency and the lack of conditioning of the examined changes by social factors. Every year, students of physiotherapy at Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń (Poland) were examined in terms of height, weight, chest circumference, balance, speed, power, agility and endurance. The results were obtained from 1161 female students and 464 male students. There was weight gain in the group of women (R2 = 0.41, p = 0.00314), deterioration of speed (for women R2 = 0.579, p = 0.001; for men R2 = 0.301, p = 0.0185) and deterioration of power (for women R2 = 0.51, p = 0.001, p = 0.001; for men R2 = 0.0432, p = 0.00303). The stability of the remaining features was also found, as well as the lack of their conditioning by social factors. Predictors of maintaining motor fitness were identified, i.e. male gender, fitness exam qualifying for studies and chest circumference. The creation of conditions and requirements encouraging greater care for the appropriate level of motor fitness of people undertaking physiotherapy studies seems justified. This observation may apply to other academia providing training for the profession of physiotherapist.

Secular Trends in Physical Fitness of Peruvian Children Living at High-Altitude

The physical fitness of children is an important marker of health, and monitoring its temporal changes provides important information for developing interventions. We aimed to: (1) describe secular trends in physical fitness across age, within each sex, in Peruvian schoolchildren; and (2) verify if these trends are also present when adjusted for changes in height and weight. We sampled 1590 children (707 in 2009; 883 in 2019), aged 6-11 years. Physical fitness was assessed with four tests from the EUROFIT battery. ANOVA and ANCOVA statistical models were used. Results showed that with increasing age, girls and boys were significantly stronger in all PF tests, except for the case of flexibility in girls. In 2019, girls were stronger (handgrip) and more flexible than in 2009; but lower values were evident in standing long jumps in both sexes. Age-by-year interactions were statistically significant for agility in both sexes, with significant differences occurring at different ages. These trends did not change when adjusted for temporal changes in height and weight. Our research provides important data for local governments to implement public policies and practices to improve physical fitness levels in children.

Normative values for hand grip and pinch strength for 6 to 18 year-olds in Saudi Arabia

BACKGROUND

Normative values for hand grip and pinch strength among children in Saudi Arabia has not been well established. Therefore, the main aim of this study is to establish normative values for hand grip and pinch strength in children aged 6 to 18 years in Saudi Arabia.

METHODS

A cross-sectional study was conducted from different 5 regions in Saudi Arabia. Participants between the age of 6 years and 18 years old were recruited through different primary and secondary schools in Saudi Arabia. Data for age, gender, Body Mass Index, and preferred hand were collected. Hand grip strength was measured using digital hand dynamometer and the tip pinch, palmar pinch, and key pinch strength were measured using the hydraulic pinch gauge.

RESULTS

A total of 616 participants included in this study (318 boys and 298 girls). Participants were stratified into 5 chronological age groups of 6-7 years, 8-9, 10-11, 12-13, 14-15, 16-17, and 18 years. The results showed an overall trend of increasing hand grip strength and pinch strength with age regardless of hand preference. Boys had significantly higher grip strength than girls in all age groups (P < 0.05).

CONCLUSION

This study established normative values for hand grip and pinch strength in the healthy Saudi pediatric and adolescent population, using boys and girls aged 6 to 18. The outcomes of this study also demonstrated that gender, age, and hand preference can all have an impact on how strong a handgrip develops.

Long-Term Trends in Changes in Physical and Motor Development Observed among Physiotherapy Students from Bydgoszcz in 2011-2020

INTRODUCTION

The aim of the study is to assess the changes in somatic and motor characteristics in adolescents studying physiotherapy from 2011-2020. It was hypothesized that there was no secular trend of morphological features, its maintenance in endurance, increased sexual dimorphism and the influence of the COVID-19 pandemic on the observed characteristics.

MATERIALS AND METHODS

Young people studying at the Collegium Medicum in Bydgoszcz were examined. Basic somatic features, endurance and coordination were measured. WHR, BMI and dimorphism indices were calculated based on the results from 538 female and 217 male examined students.

RESULTS

There was a decrease in body height with an increase in body weight in relation to the values recorded in the years 2001-2010 (BMI: women D = 0.49, Z = 2.9192; men D = 0.93, Z = 3.5746; WHR women D = 0.01, Z = 2.88491; men D = 0.02, Z = 3.5746), an increase in sexual dimorphism and a significant increase in the waist circumference of women (R2 = 0.008, p (F) = 0.0353) year by year by 0.3099 cm (p = 0.035).

CONCLUSIONS

The obtained results and the comparisons made allow us to assume that some people studying physiotherapy may have problems with meeting the standards that require physical effort.

Assessment of Motor Abilities and Physical Fitness in Youth in the Context of Talent Identification-OSF Test

(1) Background: Physical fitness during childhood is an important indicator of current and future health status. Defining physical fitness levels is a key element of talent identification in the training of children and adolescents. It is also crucial in developing a sports career path. This study sought to validate a physical fitness test (OSF test) and to determine fitness norms for children and adolescents with a special focus on talent identification within its particular sub-tests of endurance, speed, strength and power. (2) Methods: A total of 27,187 athletes who participated in the 'Athletics for all' (AFA) programme were included in the analysis. Physical fitness was assessed using a validated OSF test (3 × 10 shuttle run, standing broad jump, 1 kg medicine ball overhead throw, 4-min run). (3) Results: Four key motor abilities (speed, power, strength and endurance) were assessed in children and adolescents. The OSF test was normalised, i.e., a reference frame in the form of centile charts was developed. (4) Conclusions: The centile charts developed for particular parts of the OSF test make it possible to interpret scores in particular motor sub-tests and, first and foremost, enable users to compare a given score with results obtained by their peers.

Exploring the self-reported physical fitness and self-rated health, mental health disorders, and body satisfaction among Chinese adolescents: A cross-sectional study

Background

Physical activity (PA) and Physical fitness (PF) have received tremendous attention in the field of physical and mental health. However, limited attention has been given to the associations of self-reported physical fitness with some health-related outcomes. Given the COVID-19 pandemic is still active in many Chinese regions, assessing health-related physical fitness (HRPF) in adolescents using field-based assessment (such as a shuttle run for cardiorespiratory fitness) is unrealistic, therefore, this study was conducted via a self-reported questionnaire.

Purpose

The present cross-sectional study was aimed at delving into the relationship between self-reported physical fitness with self-rated health, depression, anxiety, and body satisfaction in adolescents. Three thousand eight hundred and seven study participants from 12 public schools in South-eastern China were recruited and 2,407 of them provided valid data on variables that this study needed for analysis.

Materials and methods

Study participants were asked to self-report their sociodemographic factors (e.g., sex, grade, age), independence, and outcomes. Generalized linear models were used to explore the associations of self-reported physical fitness (comprising general physical fitness, cardiorespiratory fitness, muscular strength, speed and agility, and flexibility) with depression, anxiety, and body satisfaction. A total of 2,407 children and adolescents with a mean age of 13.82 (±2.1) years were included in the final study analysis.

Results

Higher self-reported levels of general physical fitness and cardiorespiratory fitness were associated with better self-rated health, and body satisfaction but with lower risks of depression and anxiety.

Conclusion

The current study offered evidence on the roles of self-reported physical fitness and health-related outcomes. To facilitate health in children and adolescents, advocating fitness education, and promotion could be a feasible approach.

School-Based Comprehensive Strength Training Interventions to Improve Muscular Fitness and Perceived Physical Competence in Chinese Male Adolescents

Purpose. This research was to see how effective and feasible school-based comprehensive strength training programs are in improving muscular fitness and perceived physical competence in Chinese male adolescents. Methods. A total of 123 participants ( $13.46\pm 0.60$ years) were randomized to comprehensive strength training intervention group (CST) ( $n=62$ ) and the control group (CON) ( $n=61$ ). The training sessions were performed three times a week for ten weeks in CST. Muscular fitness (i.e., muscular strength, power, and muscular endurance) and perceived physical competence were assessed at initial testing and final testing. Results.The subjects in the CST significantly improved their mean performance in standing long jump ( $p<0.05$ ), vertical jump ( $p<0.05$ ), 1 min push-ups ( $p<0.05$ ), 1 min sit-ups ( $p<0.05$ ), handgrip strength ( $p<0.05$ ), and perceived physical competence ( $p<0.05$ ) after the intervention. Moreover, the CST were greater in standing long jump ( $p<0.05$ ), vertical jump ( $p<0.05$ ), 1 min sit-ups ( $p<0.05$ ), handgrip strength ( $p<0.05$ ), and perceived physical competence ( $p<0.05$ ) compared to the CON, but no in 1 min push-ups ( $p>0.05$ ). Conclusions. The comprehensive strength training interventions designed in this study can significantly increase male adolescents’ muscular fitness, especially in the lower extremity muscle power and abdominal core endurance, and can enhance their perceived physical competence.

Changes in the continuous leaping performance of Finnish adolescents between 1979 and 2020

The aims of this secular trend design study were: 1) to investigate whether the continuous leaping performance of Finnish adolescents (mean age 14.99 ± .61 years) changed between 6 data sets collected between 1979 and 2020, and 2) to analyse if variation in leaping performance increased from 1979 to 2020. The data for this secular trend study of 6 cohorts were collected in 1979 (n = 599), 1995 (n = 498), 1998 (n = 796), 2003 (n = 2383), 2010 (n = 1383), and 2020 (n = 719). All cohorts performed the 5-leaps test, following the same protocol. Between-cohort differences in scores were analysed using a General Linear Contrast Model. Between-cohort differences in variance were tested using Chi-square-based between-group tests. Sex, age, and BMI were used as covariates in the secular trend analyses. Continuous leaping performance demonstrated a decreasing trend in both girls and boys. Specifically, girls' scores were stable between 1979 and 1995, decreased from 1995 to 2010 and remained stable thereafter. Boys leaping performance improved from 1979 to 1995, was stable until 2003, and had declined by 2020. Within-group variation in continuous leaping was greater in girls and boys during the first decades of the 21st century than previously.

Longitudinal Association between Weight Status, Aerobic Capacity, Muscular Strength, and Endurance among New York City Youth, 2010-2017

Background: Child weight status is inversely associated with fitness, but less is known about this relationship across fitness domains. This study examined the longitudinal association between weight status and fitness domains in a large, diverse sample of children. Methods: Data were drawn from the New York City Fitnessgram (2010-2011 to 2017-2018). Height and weight were collected annually and converted to weight status using Centers for Disease Control and Prevention growth charts. Aerobic capacity, muscular strength, and endurance were measured as age and sex standardized z-scores based on the fitness performance tests. Repeated-measures multilevel models were run testing the association between weight status and 1-year lagged fitness domains. Results: The sample included 917,554 children (51.8% male, 39.3% Hispanic, 29.9% non-Hispanic Black, 13.9%, 4.7%, and 1.7% class I, II, and III obesity, respectively). For each fitness domain, fitness scores decreased with increasing weight status across all demographic categories, with the lowest fitness scores observed in children with the most severe obesity, and highest magnitude of effects for aerobic capacity, and particularly among boys, non-Hispanic Whites, and older youth. For example, compared with youth with healthy weight, youth with overweight had 0.28 standard deviation lower aerobic capacity performance [confidence interval (95% CI): -0.29 to -0.28], followed by class 1 obesity (β = -0.57, 95% CI: -0.58 to -0.57), class 2 obesity (β = -0.88, 95% CI: -0.88 to -0.88), and class 3 obesity (β = -1.19, 95% CI: -1.20 to -1.18). Conclusions: Compared with youth with healthy weight, youth at every other weight status had lower subsequent fitness, with the magnitude of the relationship increasing as weight status increased. Future research should examine interventions targeting aerobic capacity to reduce fitness disparities.

The Impact of COVID-19-Related Mitigation Measures on the Health and Fitness Status of Primary School Children in Austria: A Longitudinal Study with Data from 708 Children Measured before and during the Ongoing COVID-19 Pandemic

The COVID-19-related closing of schools and sport facilities resulted in major changes to daily routines worldwide. It was the aim of this study to investigate the impact of COVID-19-related mitigation measures on the health and fitness status of primary school children in Austria. Seven hundred and eight primary school children (7–10 years old) participated in the longitudinal study. Data on height, weight, waist circumference, and fitness were collected before (September 2019) and during the course of the COVID-19 pandemic (June 20, September 20, March 21, June 21). A significant increase in EQUI BMI_AUT (η_p² = 0.087) and significant changes (η_p² = 0.355) in waist circumference were found. Cardiorespiratory endurance (η_p² = 0.440) and action speed (η_p² = 0.221) decreased dramatically following lockdowns/school closures. In contrast, muscle strength showed no significant changes. The COVID-19-related mitigation measures intended to contain a communicable disease resulted in an acceleration of the pre-existing pandemic of overweight and obesity. The adverse combination of increasing BMI and the loss of physical fitness is likely to result in long-term negative effects on the health status of growing and developing individuals. Health professionals should therefore not only support further longitudinal observations of this “non-communicable disease” but also support intervention programs to reverse this worrying side-effect of COVID-19-associated containment policies.

Active Video Games Improve Muscular Fitness and Motor Skills in Children with Overweight or Obesity

(1) Background: Childhood obesity is an important public health problem. Children with overweight or obesity often tend to show the pediatric inactivity triad components; these involve exercise deficit disorder, pediatric dynapenia, and physical illiteracy. The aim of the study was to examine the influence of an active video games (AVG) intervention combined with multicomponent exercise on muscular fitness, physical activity (PA), and motor skills in children with overweight or obesity. (2) Methods: A total of 29 (13 girls) children (10.07 ± 0.84 years) with overweight or obesity were randomly allocated in the intervention group (AVG group; n = 21) or in the control group (CG; n = 8). The intervention group performed a 5-month AVG training using the Xbox 360® with the Kinect, the Nintendo Wii®, dance mats, and the BKOOL® interactive cycling simulator, combined with multicomponent exercise, performing three sessions per week. The control group continued their daily activities without modification. Weight, PA using accelerometers, and motor competence using the Test of Gross Motor Development 3rd edition were measured. Muscular fitness was evaluated through the Counter Movement Jump height, maximal isometric strength of knee extension and handgrip strength, and lean mass using Dual-energy X-ray Absorptiometry. Mann−Whitney U and Wilcoxon signed rank tests were performed. The biserial correlation coefficients (r) were calculated. Spearman’s correlation coefficients among PA, muscular fitness, and motor competence variables were also calculated. (3) Results: The AVG group significantly increased their knee extension maximal isometric strength (4.22 kg; p < 0.01), handgrip strength (1.93 kg; p < 0.01), and jump height (1.60 cm; p < 0.01), while the control group only increased the knee extension maximal isometric strength (3.15 kg; p < 0.01). The AVG group improved motor competence and light physical activity (p < 0.05) and decreased sedentary time (p < 0.05). Lean mass improved in both AVG group and CG (p < 0.05). Lastly, the percentage of improvement of motor skills positively correlated with the percentage of improvement in vigorous PA (r = 0.673; p = 0.003) and the percentage of improvement in CMJ (r = 0.466; p = 0.039). (4) Conclusions: A 5-month intervention combining AVG with multicomponent training seems to have positive effects on muscle fitness, motor competence, and PA in children with overweight or obesity.

Pediatric Co-Norms for Finger Tapping, Grip Strength, and Grooved Pegboard in a Community Sample

OBJECTIVE

Motor tests, including Finger-Tapping Test, Grooved Pegboard Test, and Grip Strength Test, are frequently used by neuropsychologists when assessing pediatric populations. Many of the norms available for these measures are outdated, have not been co-normed, and have samples with limited diversity. This study aims to provide updated, co-norms for three commonly used motor tasks with a diverse population.

METHOD

Participants (n = 476; age range 6-14) were recruited from community settings to complete each of the three motor tests.

RESULTS

Results demonstrate generally improved performance across ages with no significant difference between performance of males and females on the Grooved Pegboard Test or the Finger Tapping Test. The only significant findings were on the Grip Strength Test where 12-14-year-old boys demonstrated stronger performance on the dominant hand.

CONCLUSION

This study provides updated and co-normed data on frequently used motor tasks with a diverse pediatric sample, which are useful for clinicians.

The associations of muscle mass with glucose and lipid metabolism are influenced by body fat accumulation in children and adolescents

OBJECTIVE

To evaluate the prevalence of hyperglycemia and dyslipidemia among different body composition and investigate the associations of body composition indicators, especially the muscle mass, with glucose and lipids metabolism in children and adolescents.

METHODS

This nationwide cross-sectional study included 8,905 children and adolescents aged 6 to 18 years. All participants underwent dual-energy x-ray absorptiometry and their blood-concentrated glucose and lipids (including TC, TG, LDL-C and HDL-c) were measured. Mixed model, hierarchical analysis, and piecewise regression were used to study the effect of body composition indicators, especially the muscle mass, on glucose and lipids metabolism.

RESULTS

The greatest prevalence of high total cholesterol (TC, 6.9% and 6.9%) and high triglyceride (22.3% and 6.6%) was found in both boys and girls with high muscle mass and high fat mass, and girls with high muscle mass and high fat mass also had the highest prevalence of hyperglycemia (7.1%). After fat stratification, higher muscle mass was associated with lower odds of hyperglycemia (OR = 0.62; 95%CI: 0.46,0.84; P = 0.002) and muscle mass was inversely associated with TC (β = -0.07; 95%CI: -0.12,-0.03; P < 0.001) in boys with normal fat mass, but high muscle mass was not significantly associated with hyperglycemia and TC in high-fat-mass group (P = 0.368 and 0.372).

CONCLUSIONS

The body composition phenotype of high muscle and high fat mass have the highest prevalence of dysglycemia and dyslipidemia. Higher muscle mass was associated with a lower risk of hyperglycemia and TC levels in individuals only with normal fat mass.

Muscle endurance of Brazilian children and adolescents: a systematic review of the literature

ABSTRACT Muscle endurance (ME) is considered to be an important indicator of health-related fitness in childhood and adolescence. The present study aimed to identify and summarize the evidence on the prevalence of adequate ME in Brazilian children and adolescents (6 to 18 years old). A systematic search of studies published from 2009 to 2019 was performed in six databases (LILACS; SciELO; SportDiscus; Medline/PubMed; Web of Science; Scopus). We found 16,168 articles, 20 of which met the eligibility criteria and were included in this review for data extraction and assessment of their risk of bias. Among the 23,805 children and adolescents participating in the studies, 43.5% of the total (43.7% of boys and 41.0% of girls) had adequate abdominal ME. Different test batteries were reported, the main ones being PROESP/BR®, FITNESSGRAM®, and AAHPERD®. Most studies were carried out in the South (50.0%) and Southeast (20.0%) regions of Brazil. Regarding the distribution of studies by geographic region and human development index (HDI), there were no disparities in ME between studies conducted in regions with a lower HDI (43.1% for the Northeast and 32.2% for the North) and those with a higher HDI (46.8% for the South and 33.1% for the Southeast). We conclude that less than half of Brazilian children and adolescents of both genders have an abdominal ME adequate for health, with slightly lower values among females.

Prospective physical fitness status and development of cardiometabolic risk in children according to body fat and lifestyle behaviours: The IDEFICS study

BACKGROUND

Elevated cardiometabolic risk (CMR) is an important factor for cardiovascular diseases later in life while physical fitness seems to decrease CMR.

OBJECTIVE

Thus, the aim of the present study is to assess the association between muscular fitness (MF) and cardiorespiratory fitness (CRF) on CMR in European children, both cross-sectional and longitudinally.

METHODS

A total of 289 children (49.5% males) from eight European countries, aged 6 to 9, with longitudinal information on blood pressure, triglycerides, total cholesterol, HDL-cholesterol, homoeostasis model assessment, body mass index, data on fitness level, objectively measured physical activity (PA), diet quality, and total screen time were included. A CMR score was calculated and dichotomized. MF and CRF were also dichotomized. Cross-sectional and longitudinal multilevel logistic regressions adjusting for lifestyle behaviours were performed.

RESULTS

Reaching a high level of MF during childhood as well as remaining in that level over-time were associated with an 82% and 62% lower probability of high CMR at follow-up, respectively. Also, children who became top CRF over time, showed a 77% lower probability (P < 0.05) of being in the highest CMR quartile at follow-up, independently of sociodemographic and lifestyle indicators.

CONCLUSIONS

A high MF at early childhood and during childhood reduces the odds of having CMR. Same occurs with the improvement of CRF during childhood. These findings highlight the importance of enhancing fitness to avoid CMR already in children.

Hand grip strength in boys and girls from summer school camps in Spain, 1900-1925. A comparison with 21st century data

OBJECTIVES

The Spanish National Pedagogic Museum (Museo Pedagógico Nacional, MPN), founded by La Institución Libre de Enseñanza, organized the first summer school camps in Spain and their initiative was followed by other institutions in this country. MPN prepared anthropological forms for those sojourns, which included information about both metric and physiological measurements of the schoolchildren. The aim of the current work is to analyze hand grip strength data and to compare them with recent values.

METHODS

The initial sample included 2418 schoolchildren from 6 to 16 years old (1467 males, 951 females) attending the camps, but after preliminary analyses, the study was restricted to 1073 boys and 818 girls in the 1900-1925 interval. Three time periods were established and 13 categories of height at camp entry, every 5 cm. Normality tests were run as well as contrasts of means, and both average values and percentiles were calculated for hand grip strength in both hands, as a function of age and height categories.

RESULTS

The 1900-1925 interval was chosen since there were no significant differences among hand grip data within that period. Results show that children attending the camps had dynamometry values in both hands well below the current ones, both with reference to their height and to their age.

CONCLUSIONS

Camp attendees displayed very low values of height and hand grip strength in both hands. Both are significantly lower than contemporary values, manifesting a secular effect.

The Effect of Intensity, Frequency, Duration and Volume of Physical Activity in Children and Adolescents on Skeletal Muscle Fitness: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Physical activity could improve the muscle fitness of youth, but the systematic analysis of physical activity elements and muscle fitness was limited. This systematic review and meta-analysis aim to explore the influence of physical activity elements on muscle fitness in children and adolescents. We analyzed literature in Embase, EBSCO, Web of Science, and PubMed databases from January 2000 to September 2020. Only randomized controlled studies with an active control group, which examined at least 1 muscle fitness evaluation index in individuals aged 5–18 years were included. Articles were evaluated using the Jaded scale. Weighted-mean standardized mean differences (SMDs) were calculated using random-effects models. Twenty-one studies and 2267 subjects were included. Physical activity had moderate effects on improving muscle fitness (SMD: 0.58–0.96, p < 0.05). Physical activity element subgroup analysis showed that high-intensity (SMD 0.68–0.99, p < 0.05) physical activity <3 times/week (SMD 0.68–0.99, p < 0.05), and <60 min/session (SMD 0.66–0.76, p < 0.01) effectively improved muscle fitness. Resistance training of ≥3 sets/session (SMD 0.93–2.90, p < 0.01) and <10 repetitions/set (SMD 0.93–1.29, p < 0.05) significantly improved muscle fitness. Low-frequency, high-intensity, and short-duration physical activity more effectively improves muscle fitness in children and adolescents. The major limitation of this meta-analysis was the low quality of included studies. The study was registered in PROSPERO with the registration number CRD42020206963 and was funded mainly by the Ministry of Education of Humanities and Social Science project, China.

Motor Competence and Health-related Fitness of School-Age Children: A Two-Year Latent Transition Analysis

PURPOSE

The aims of this study were twofold: 1) to identify latent physical performance profiles of motor competence (MC) and cardiorespiratory (CF) and muscular fitness (MF) among school-aged children and 2) explore transition probabilities in physical performance profiles over a two-year period.

METHODS

The present sample comprised 1148 (583 girls, 565 boys) elementary school students (baseline Mage = 11.27 ± .32), and data were collected annually (equal intervals) over a period of two years which resulted in a total of three measurements. The measures used were the throwing-catching combination test, 5-leaps and two-legged jumps from side-to-side test (MC), 20-meter shuttle run test (CF), and curl-up and push-up tests (MF). Latent transition analysis was used to identify and track physical performance profiles derived from the measurements of MC, CF, and MF scores.

RESULTS

The key findings were: 1) three physical performance profiles were identified: a) Low (28 % of the sample; lowest level in each category), b) Moderate (43 % of the sample; higher MC, CF and MF than Low), c) High (29 % of the sample; highest MF); 2) the number of physical performance profiles and probability to belong to a given profile were stable across time; 3) the highest transition probability was found in the High group, where some students had transitioned to the Moderate group at T2, and 4) girls were most likely to belong to the Low.

CONCLUSION

Results demonstrated that children's physical performance profiles are stable from late childhood to early adolescence. This study suggests that the early elementary school years are essential for the development of children's MC and health-related fitness.

The Effects of Active Video Games on Health-Related Physical Fitness and Motor Competence in Children and Adolescents with Healthy Weight: A Systematic Review and Meta-Analysis

(1) Background: Poor levels of physical fitness and motor skills are problems for today’s children. Active video games (AVG) could be an attractive strategy to help address them. The aim was to investigate the effects of AVG on health-related physical fitness and motor competence in children and adolescents with healthy weight. (2) Methods: Randomized and non-randomized controlled trials investigating the effects of AVG programs on health-related physical fitness and motor competence were included. Two different quality assessment tools were used to measure the risk of bias. Twenty articles met the inclusion criteria and the variables of interest were body mass index (BMI), body fat, cardiorespiratory fitness (CRF), muscular fitness and motor competence. (3) Results: AVG interventions seem to have benefits in BMI when lasting longer than 18 weeks (SMD, −0.590; 95% IC, −1.071, −0.108) and in CRF (SMD, 0.438; 95% IC, 0.022, 0.855). AVG seems to be a promising tool to improve muscular fitness and motor competence but the effects are still unclear due to the lack of evidence. (4) Conclusions: AVG seem to be an effective tool for improving some components of health-related physical fitness and motor competence in healthy-weight children and adolescents, but the effect on some fitness components needs further research. Therefore, AVG may be included as a strategy to improve health.

Temporal Trends in the Standing Broad Jump Performance of 10,940,801 Children and Adolescents Between 1960 and 2017

BACKGROUND

The standing broad jump (SBJ) is an excellent functional measure of explosive lower-body strength that is significantly related to health among children and adolescents.

OBJECTIVES

The aim of this study was to estimate national (country-level) and international (pooled global data) temporal trends in SBJ performance for children and adolescents, and to examine the relationships between national trends in SBJ performance and national trends in health-related and socioeconomic/demographic indicators.

METHODS

Data were obtained from a systematic search of studies reporting temporal trends in SBJ performance for 9- to 17-year-olds, and by examining national fitness datasets. Sample-weighted regression models estimated trends at the study/dataset-country-sex-age level, with national and international trends estimated by a post-stratified population-weighting procedure. Pearson's correlations quantified relationships between national trends in SBJ performance and national trends in health-related and socioeconomic/demographic indicators.

RESULTS

Data from 34 studies/datasets were extracted to estimate trends for 10,940,801 children and adolescents from 24 high-, 4 upper-middle-, and 1 low-income countries between 1960 and 2017. Collectively, there was a negligible (per decade) improvement in SBJ performance of 1.73 cm (95% CI 1.71-1.75), 0.99% (95% CI 0.97-1.01) or a standardized effect size of 0.07 (0.07-0.07) over the entire period, with the rate of improvement steady from the 1960s to the 1980s, slowing in the 1990s, before declining. Sex- and age-related temporal differences were negligible. Trends differed between countries, with most countries experiencing declines. National trends in SBJ performance were not significantly related to national trends in health-related and socioeconomic/demographic indicators.

CONCLUSIONS

SBJ performance of children and adolescents has declined since 2000 (at least among most of the countries in this analysis) and is suggestive of a modern decline in functional explosive lower-body strength. Growing recognition of the importance of muscular fitness as a marker of population health highlights the need for continued tracking of temporal trends in SBJ, especially among low- and lower-middle-income countries for which temporal data are lacking.

PROSPERO REGISTRATION NUMBER

CRD42013003657.

Secular trends in muscular fitness from 1983 to 2014 among Slovenian children and adolescents

Low physical fitness has been found to be associated with many chronic diseases and medical conditions. Knowledge of secular trends in physical fitness is important to initiate countermeasures for addressing negative trends. The aim of this study was to analyze secular trends in health-related muscular fitness in Slovenian children and adolescents between 1983 and 2014. Data were collected as part of "The Analysis of Children's Development in Slovenia (ACDSi)" study in 1983, 1993/94, 2003/04, and 2013/14. Anthropometry (body weight, height, BMI, and triceps skinfold) and muscular fitness (standing long jump, bent-arm hang, and sit-ups 60 s test) of 18730 (9168 female) students from primary and secondary schools were recorded. The secular trend was analyzed considering anthropometry. The results showed that anthropometric measures had an increasing trend and overall muscular fitness had a decreasing trend. Leg muscle power decreased over the decades in all age groups (relative difference between -1.5% and -2.6%), being more pronounced in boys. Arm muscle strength decreased in two younger age groups (range -21.1% to -42.7%, 6-10, and 11-14 years), but not in the oldest group (15-19 years), where the increase occurred in both genders (0.4% to 9.3%). In terms of decades, the largest negative changes (-30.1%) occurred from 1993/94 to 2003/04 and the smallest changes (-4.2%) from 2003/04 to 2013/14. The overall trend in repetitive core strength surprisingly increased (1.1% to 18.3%). There is a need to promote healthy lifestyles, raise parental awareness and use all government resources to redirect the negative trend in physical fitness.

A Systematic Analysis of Temporal Trends in the Handgrip Strength of 2,216,320 Children and Adolescents Between 1967 and 2017

OBJECTIVE

To estimate national and international temporal trends in handgrip strength for children and adolescents, and to examine relationships between trends in handgrip strength and trends in health-related and sociodemographic indicators.

METHODS

Data were obtained through a systematic search of studies reporting temporal trends in the handgrip strength for apparently healthy 9-17-year-olds, and by examining large national fitness datasets. Temporal trends at the country-sex-age level were estimated by sample-weighted regression models relating the year of testing to mean handgrip strength. International and national trends were estimated by a post-stratified population-weighting procedure. Pearson's correlations quantified relationships between national trends in handgrip strength and national trends in health-related/sociodemographic indicators.

RESULTS

2,216,320 children and adolescents from 13 high-, 5 upper-middle-, and 1 low-income countries/special administrative regions between 1967 and 2017 collectively showed a moderate improvement of 19.4% (95% CI 18.4-20.4) or 3.8% per decade (95% CI 3.6-4.0). The international rate of improvement progressively increased over time, with more recent values (post-2000) close to two times larger than those from the 1960s/1970s. Improvements were larger for children (9-12 years) compared to adolescents (13-17 years), and similar for boys and girls. Trends differed between countries, with relationships between national trends in handgrip strength and national trends in health-related/sociodemographic indicators negligible-to-weak and not statistically significant.

CONCLUSIONS

There has been a substantial improvement in absolute handgrip strength for children and adolescents since 1967. There is a need for improved international surveillance of handgrip strength, especially in low- and middle-income countries, to more confidently determine true international trends.

PROSPERO REGISTRATION NUMBER

CRD42013003657.

Temporal Trends in the Standing Broad Jump Performance of United States Children and Adolescents

Purpose: To estimate temporal trends in broad jump performance for United States youth, a marker of muscular fitness and health. Method: Electronic databases, topical systematic reviews, and personal libraries were systematically searched for studies reporting descriptive standing broad jump data for apparently healthy United States youth (age 10-17 years). Temporal trends at the sex-age level were estimated using sample-weighted regression models associating the year of testing to mean jump performance, with national trends standardized to the year 1985 using a post-stratified population-weighting procedure. Results: Collectively, there was a small increase of 12.6 cm (95%CI: 12.5 to 12.7) or 7.9% (95%CI: 7.1 to 8.6) in 65,527 United States youth between 1911 and 1990. Increases were greater for girls (change in means [95% CI]: 17.1 cm [16.9 to 17.3]; 11.4% [10.7 to 12.2]) compared to boys (change in means [95% CI]: 8.5 cm [8.3 to 8.7]; 4.6% [3.8 to 5.4]), but did not differ between children (10-12 years) and adolescents (13-17 years). Increases in broad jump performance were not always uniform across time, with steady and progressive increases observed for boys and children, respectively, and a diminishing rate of increase observed for girls and adolescents. Conclusions: Muscular fitness is a good marker of health, so greater broad jump performance from 1911 to 1990 may reflect corresponding changes in health. Routine assessment of broad jump performance may be useful to monitor trends in health and muscular fitness of United States youth due to its practicality, scalability, and predictive utility.

The longitudinal relationship between dietary intake, physical activity and muscle strength among adolescents

The longitudinal relationship between muscle strength, dietary intake and physical activity among adolescents is not well understood. We investigated the trend and longitudinal effects of dietary intakes and physical activity scores on muscle strength in adolescents. This prospective cohort study consisted of 436 adolescents (134 males; 302 females) aged 13 years at baseline (2012) who were followed up at the ages of 15 (2014) and 17 (2016) years, respectively. We measured muscle strength using a calibrated hand dynamometer, estimated dietary intake with a 7-d dietary history and physical activity scores with a validated physical activity questionnaire for older children. A generalised estimating equation was used to examine the effect of dietary intakes and physical activity on muscle strength changes. The analysis was performed separately by sex. The muscle strength for males and females had increased within the 5-year period. The dietary intakes (energy and macronutrients) also increased initially but plateaued after the age of 15 years for both sexes. Females recorded a significant declining trend in physical activity scores compared with males as they grew older. A significant positive longitudinal relationship was found between protein (β = 0·035; P = 0·016), carbohydrate intake (β = 0·002; P = 0·013) and muscle strength among males. However, no longitudinal relationship was found between dietary intake, physical activity and muscle strength among females. Higher protein and carbohydrate intake among males was associated with higher muscle strength but was not observed in females. Nutrition and physical activity focusing on strength building are required in early adolescence and need to be tailored to males and females accordingly.

Temporal trend of cardiorespiratory endurance in urban Catalan high school students over a 20 year period

Background

Physical fitness is considered an important indicator of health in adolescents. However, in recent years several studies in the scientific literature have shown a considerable lower trend and an alarming worsening of the current adolescents’ physical condition when comparing with previous decades, especially in urban populations. The aim of the current study was to analyse the temporal trend in cardiorespiratory endurance (CRE) in urban Catalan adolescents over a 20-year period (1999–2019).

Methods

A cross-sectional analysis study considering the 20-m Shuttle Run test (SRT) results obtained in the last 20 years was carried out. 1,701 adolescents between 15 and 16 years old (914 boys and 787 girls) were divided into four groups, corresponding to consecutive periods of five years (Group 1: 1999–2004; Group 2: 2005–2009; Group 3: 2010–2014 and Group 4: 2015–2019). ANOVA was used to test the period effect on CRE and post hoc Bonferroni analysis was performed to test pairwise differences between groups (p < 0.05).

Results

Results showed a significantly lower performance in CRE in both sexes. The percentual negative difference was 0.67%, 9.6% and 7% for boys and 5.06%, 14.97% and 9.41% for girls, when comparing the performance in 20-m Shuttle Run test for the first period, respectively.

Conclusions

Results suggest that the physical fitness of Catalan urban adolescents is lower in both sexes when comparing the different analysed periods of time. Therefore, CRE adolescents should be improved in order to help to protect against cardiovascular disease and other health risks in adulthood.

Italian Physical Fitness Decline: A True Fact or a Mindset? A 10-Year Observational Perspective Study

Evidence regarding a putative physical fitness decline remains less well documented for Italian children and adolescents. An update review of data collection articles was undertaken concerning motor performances (power, strength, speed-agility and indirect cardiorespiratory fitness) of children and adolescents worldwide and compared with 2859 11-12-year-old Italian students of both sexes, throughout a ten-year observational period. Lower limb explosive strength (standing broad jump), flexibility (sit-and-reach), endurance (Cooper) and speed (SP-30) performances of sixth grade Italian students showed nearly stable trends, with no differences during the observed decade, in both sexes. This 10-year perspective study confirmed that Italian physical fitness levels flatlined rather than actually declined. According to these study data, the decline in physical fitness of the Italian youth is ostensible and needs a further in-depth analysis.

Changes in Physical Fitness Among Preschool Children From Kraków (Poland) From 2008 to 2018

BACKGROUND

The aim of this study was to analyze the secular changes of the physical fitness of preschool children from Kraków, Poland between 2008 and 2018.

METHODS

The study group consisted of 2143 children (3- to 7-y-olds; 2008 cohort included 1037 children and the 2018 cohort included 1106 children). The following physical fitness tests were carried out: overhead medicine ball throw, standing broad jump, sit-and-reach test, and handgrip strength. Statistical differences between the cohorts were obtained using 2-way analysis of variance and Tukey tests.

RESULTS

Negative changes were noted for the standing broad jump and its relative results among boys. A negative trend was also observed for flexibility and ball throw. Positive changes were noted for the standing broad jump among girls, as well as the absolute and normalized results of handgrip strength in both sexes. Besides the flexibility, observed discrepancies were practically significant between the age groups. Differences between the cohorts reached practical significance in the case of absolute and normalized handgrip strength.

CONCLUSIONS

There was at least partial progress in the children's fitness. Physical fitness, in turn, is one of the most important health markers. Moreover, its low level is a predictor of diseases, including metabolic and cardiovascular ones, lower academic performance, and psychosocial problems.

A 47-Year Comparison of Lower Body Muscular Power in Spanish Boys: A Short Report

Much of the evidence examining temporal trends in fitness among youth has found a decrease in measures of muscular strength and muscular power over recent decades. The aim of this study was to examine trends in lower body muscular power in Spanish boys over 47 years. In 1969 140 boys (10-11 years; body mass index = 19.24, SD = 2.91 kg/m²) and in 2016, 113 boys (10-11 years; body mass index = 19.20, SD = 3.15 kg/m²) were recruited. Lower body power was assessed using the vertical jump (VJ) and standing long jump (SLJ) tests. Significant differences and a large effect size were shown between groups in the SLJ (p = 0.001; d = 0.94) and the VJ (p = 0.001; d = 0.66). SLJ data in 1969 were higher (1.52 m, SD = 0.19) when compared to the 2016 data (1.34 m, SD = 0.18). The VJ performance of the 1969 sample was also higher (25.95 cm; SD = 6.58) than the 2016 sample (21.56 cm; SD = 4.72). SLJ and VJ performance of the 2016 group decreased 11.8% and 16.9%, respectively. There were no significant differences between groups in body mass index. The results indicate a secular decline in lower body muscular power in 10-11-year-old Spanish boys with no significant changes in body mass index over the 47-year study period.

Secular Trends in Physical Fitness of Children and Adolescents: A Review of Large-Scale Epidemiological Studies Published after 2006

Physical fitness (PF) of children and adolescents is an important resource for their future health. Population-based studies, however, rarely report secular changes of PF, although monitoring of these is crucial to deriving information for adequate interventions. This review aims to report trends in PF of children and adolescents. A literature search was conducted in PubMed in July 2019. Cohort studies published in English allowing statements to be made on trends in PF by comparing youth between the ages of four and 18 years were included. The review identified 24 studies from 16 countries meeting the inclusion criteria, with an overall sample size of more than 860,000 children and adolescents. Through a standardized quality assessment tool, we classified two studies as strong, 21 as moderate, and only one as weak. We analyzed specific secular trends separately for the five different dimensions: endurance, strength, speed, flexibility, and coordination. The majority of studies report a decline of PF over time; however, a few studies report conflicting results. Performance in endurance, strength, and flexibility decreased over time, whereas there was no consistent trend reported for speed and coordination. Overall, there is no international standard on examining and reporting changes or secular trends in PF of children and adolescents, and comparability of studies is limited due to heterogeneous conditions of conducting and analyzing PF tests. Consequently, standardized and consistent international monitoring should be implemented.

Normative Values for Muscular Fitness for Chinese Children and Adolescents Aged 7–18 Years

The primary aim of this study was to establish sex and age-specific muscular fitness (MF) norms for Chinese children and adolescents aged 7–18 years old. The secondary aim was to compare their MF values with those of children and adolescents in other countries and regions. The MF of 93,755 participants from China was evaluated by handgrip strength (upper limbs strength), sit-ups (trunk strength) and a standing broad jump (lower limbs strength), with a total of 90,424, 90,281 and 90,663 data values, respectively. The Lambda-Mu-Sigma (LMS) method was used to calculate smooth curves and table data. The MF of Chinese boys was higher than that of girls in all age groups. After the age of 11, the growth rate of boys accelerated while that of girls slowed down. Age-related changes were larger for boys than for girls. In the international comparison, all the MF indicators of Chinese children and adolescents were lower than those of their Japanese peers but were higher than those of their European peers, with the exception of handgrip strength. The results of this study can be used to evaluate, monitor and apply interventions that improve MF. They can also be used to compare trends across countries and regions.

Profiling the health-related physical fitness of Irish adolescents: A school-level sociodemographic divide

Background and aims

Examining factors that may explain disparities in fitness levels among youth is a critical step in youth fitness promotion. The purpose of this study was twofold; 1) to examine the influence of school-level characteristics on fitness test performance; 2) to compare Irish adolescents’ physical fitness to European norms.

Methods

Adolescents (n = 1215, girls = 609) aged 13.4 years (SD .41) from a randomised sample of 20 secondary schools, stratified for gender, location and educational (dis)advantage, completed a series of field-based tests to measure the components of health-related physical fitness. Tests included: body mass index; 20 metre shuttle run test (20 m SRT); handgrip strength; standing broad jump (SBJ); 4 x 10 metre shuttle run; and back-saver sit-and-reach (BSR).

Results

Overall, boys outperformed girls in all tests, aside from the BSR (p < 0.005, t-test, Bonferroni correction). Participants in designated disadvantaged schools had significantly higher body mass index levels (p < 0.001), and significantly lower cardiorespiratory endurance (20 m SRT) (p < 0.001) and muscular strength (handgrip strength) (p = 0.018) levels compared to participants in non-disadvantaged schools. When compared to European norms, girls in this study scored significantly higher in the 20 m SRT, 4 x 10 metre shuttle run and SBJ tests, while boys scored significantly higher in the BSR test (Cohen’s d 0.2 to 0.6, p < 0.001). However, European adolescents had significantly higher handgrip strength scores (Cohen’s d 0.6 to 0.8, p < 0.001).

Conclusion

Irish adolescents compared favourably to European normative values across most components of HRPF, with the exception of muscular strength. School socioeconomic status was a strong determinant of performance among Irish adolescents. The contrasting findings for different fitness components reiterate the need for multi-component testing batteries for monitoring fitness in youth.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Efficacy of School-Based Interventions for Improving Muscular Fitness Outcomes in Adolescent Boys: A Systematic Review and Meta-analysis

BACKGROUND

It has been reported that boys' and girls' physical activity (PA) levels decline throughout adolescence. Boys are at risk of physical inactivity during adolescence; however, in intervention research, they are an under-represented group relative to girls. It is suggested that the school environment may be central to developing interventions that support adolescents in meeting the current PA guidelines. The aim of this systematic review and meta-analysis was to investigate the efficacy of school-based physical activity interventions for improving muscular fitness (MF) in adolescent males.

METHODS

This systematic review and meta-analysis followed the preferred reporting systems for meta-analyses guidelines and was registered on PROSPERO (Registration number: CRD42018091023). Eligible studies were published in English within peer-reviewed articles. Searches were conducted in three databases, with an additional grey literature search in Google Scholar. Studies investigating MF outcomes were included.

RESULTS

There were 43 data sets identified across 11 studies, from seven countries. Overall methodological quality of the studies was moderate-to-strong. Interventions targeting MF evidenced a small-to-medium effect (g = 0.32, CI 0.17, 0.48, p < 0.00). Subgroup analyses of MF delivery method resulted in small-to-medium effects: upper limb MF measures (g = 0.28, 95% CI - 0.02, 0.58, p = 0.07), lower limb MF measures (g = 0.28, 95% CI 0.09, 0.68, p = 0.03), combined MF activities (g = 0.24, 95% CI - 0.04 to 0.49, p = 0.05), plyometric activities (g = 0.39, 95% CI 0.09, 0.68, p = 0.01), body weight (g = 0.27, 95% CI - 0.10, 0.65, p = 0.15), and traditional MF methods (g = 0.43, 95% CI 0.09, 0.78, p = 0.01).

CONCLUSIONS

School-based interventions which aimed to increase MF outcomes in adolescent boys demonstrated small-to-moderate effects. Traditional and plyometric methods of resistance training appear to be the most effective form of PA delivery in adolescent males. More quality research is required to assess the impact of MF delivered in the school environment to inform future intervention design.

Prenatal exposure to di-(2-ethylhexyl) phthalate and decreased skeletal muscle mass in 6-year-old children: A prospective birth cohort study

BACKGROUND/AIM

Phthalate is a well-known endocrine-disrupting chemical that has anti-androgenic effects. Although there are several studies on the relationship between body composition and phthalate, studies that investigated the effects of phthalate on skeletal muscle during childhood are lacking.

METHODS

We analyzed data from 481 mother-and-child pairs enrolled in the Environment and Development of Children cohort in South Korea. We examined the association between phthalate metabolites (mono [2-ethyl-5-hydroxyhexyl] phthalate [MEHHP], mono [2-ethyl-5-oxohexyl] phthalate [MEOHP], molar sum of MEHHP and MEOHP [Σ DEHP], and mono-n-butyl phthalate [MnBP]) in prenatal maternal urine and children's urine at the age of 6, and body composition indices (body mass index [BMI] z-score, percentage of fat mass, fat mass index, percentage of skeletal muscle, and the skeletal muscle index [SMI]) measured when the child was 6 years using a bioelectrical impedance analyzer.

RESULTS

A 2-fold increase in Σ DEHP and MnBP in the prenatal maternal urine was significantly associated with a -0.07 unit (95% CI: -0.11, -0.03) and -0.09 unit (95% CI: -0.14, -0.03) change in SMI, respectively, in 6-year old girls alone. BMI z-score was also negatively associated with a 2-fold increase in MEHHP and MnBP in prenatal maternal urine as -0.11 unit (95% CI: -0.22, -0.01) and -0.15 unit (95% CI: -0.28, -0.02) change, respectively, only among girls. Among boys, phthalate metabolites in the prenatal and children's urine were not significantly associated with any body composition indices.

CONCLUSIONS

Our longitudinal study shows that high levels of prenatal exposure to phthalates are significantly associated with decreased SMI among girls. We can postulate that anti-androgenic effects of phthalates during pregnancy may affect girl offspring's muscle growth.

Handedness heritability in industrialized and nonindustrialized societies

In modern societies, there is a decreased usage of traditional weapons to settle interpersonal or inter-group disputes compared to usage in traditional societies, possibly affecting the frequency-dependent selection on the handedness polymorphism. Another societal difference is the extensive automation of hard manual labour (including agriculture) in industrialized societies, relaxing the selection for hand specialization. Thus, selection of handedness is likely to differ between traditional and modern societies. As heritability determines the relative speed of evolutionary dynamics, handedness heritability was compared between industrialized and non-industrialized societies. First, individuals were sampled from a non-industrialized area in Indonesia, where violent conflicts are relatively frequent and tribal wars have been prevalent recently. Handedness was recorded directly or indirectly for 11,490 individuals belonging to 650 independent pedigrees, and handedness heritability was estimated using a pedigree-based animal model. Second, estimates of handedness heritability derived from published sources were collected to compare heritability estimates, accounting for various confounding variables. Non-industrialized countries displayed a significantly higher heritability value (h2 = 0.56) than that of industrialized countries (h2 = 0.20). Heritability decreased with time along the twentieth century in industrialized countries, independently of the frequency of left-handedness, and independently of the method used to measure handedness. In conclusion, the data are consistent with a decrease in handedness heritability following the industrialization process and/or the associated decrease in violence using traditional weapons. The difference in heritability between industrialized and non-industrialized countries suggests that selection of handedness is thus likely to differ between traditional and modern societies.

Change and Stability in Sibling Physical Fitness: The Portuguese Sibling Study

PURPOSE

This study aims to 1) describe mean changes in muscular and motor fitness components in sibships over 2 yr, 2) analyze individual tracking of fitness within sibships, 3) investigate sibling resemblance in fitness over time, and 4) examine the joint influence of biological, behavioral, and familial characteristics on fitness.

METHODS

The sample comprises 166 Portuguese biological sibling pairs (brother-brother, sister-sister, brother-sister) age 9-17 yr assessed at baseline and 2 yr later. Physical fitness components were measured with standardized tests. Percentage body fat and biological maturation were assessed, and physical activity, diet, screen time, and familial characteristics were obtained by questionnaires. Multilevel models were used to analyze the clustered longitudinal data.

RESULTS

Crude results showed that, on average, all sib-types increased their muscular and motor fitness components from baseline to follow-up (except sister-sister pairs in standing long jump and shuttle run). When adjusted for covariates, the mean changes were no longer significant. Individual tracking was moderate to high for the muscular component but low to moderate for the motor component. Consistency in sibling resemblance was higher in sister-sister pairs than in brother-brother and brother-sister pairs. More mature sibs were fitter in both components, whereas siblings with higher body fat percentage were less fit. Screen time, physical activity, and parental occupation were not associated with fitness components.

CONCLUSIONS

Biological characteristics were more strongly associated with fitness components than individual behaviors and familial characteristics. Furthermore, the muscular component tracked better than the motor component. Sister-sister pairs had greater resemblance in fitness over time compared with brother-brother or sister-brother pairs.

Cardiorespiratory and muscular fitness in young adult Finnish men between 2003 and 2015

INTRODUCTION

Physical fitness is strongly related to health and may offer valuable information about public health. We investigated trends in physical fitness, leisure-time physical activity (LTPA), and anthropometry of young healthy adult Finnish men in representative population-based samples between 2003 and 2015.

METHODS

Three independent cross-sectional samples of 18- to 35-year-old Finnish men were assessed in 2003 (n = 889), 2008 (n = 803), and 2015 (n = 690). Cardiorespiratory (VO₂ max) and muscular fitness (1-minute sit-ups and push-ups), body mass, and height were measured. Self-reported LTPA was assessed.

RESULTS

After adjusting for age, education, and smoking, cardiorespiratory fitness was higher in 2003 (mean: 43.5, 95%CI: 42.9-44.1 mL/kg/min) compared to 2008 (41.3, 95%CI: 40.7-41.9 mL/kg/min) and 2015 (40.6, 95%CI: 40.0-41.2 mL/kg/min) (P < .001), whereas no difference was observed between 2008 and 2015. The lowest values in muscular fitness were observed in 2003, while no clear trends were further noticed. The adjusted BMI was higher in 2008 (25.1, 95%CI: 24.9-25.4) and 2015 (25.3, 95%CI: 25.3, 95%CI: 25.0-25.6) compared to 2003 (24.5, 95%CI: 24.3-24.8) (P < .005). In 2015, a higher proportion of individuals exercised at least four times per week compared to 2003 and 2008 (P < .05).

CONCLUSION

The decrease in cardiorespiratory fitness that took place between 2003 and 2008 plateaued after 2008. The plateau is in accordance with the previously observed trend of 5-10 years younger Finnish men. Moreover, muscular fitness was for the most part higher in 2008 and 2015 compared to 2003. Efforts directed to promote regular physical activity and improve physical fitness are needed.

Trends in Physical Fitness Among School-Aged Children and Adolescents: A Systematic Review

Introduction and Objective: This systematic review aimed to analyse the international evolution of fitness with its distributional changes in the performance on tests of physical fitness among school-aged children and adolescents. Methods: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the search was undertaken in four international databases (ERIC, PubMed, Scopus, and Web of Science) to identify the studies reporting temporal trends in the physical fitness among school-aged children and adolescents. Results: A total of 485 potential articles were identified, of which 19 articles were relevant for the qualitative synthesis; 1,746,023 children and adolescents from 14 countries (China, Finland, Sweden, Belgium, New Zealand, Denmark, Spain, Norway, Mozambique, Poland, USA, Lithuania, Portugal, Canada), for the period between 1969 and 2017 were included. The subjects were tested using 45 motor tests from eight battery tests. The quality of the study in eight articles was rated as strong, while in 11 articles it was rated as moderate. Discussion: The vast majority of studies show a constant decline in strength and endurance. Three Chinese studies show an increase in strength from 1985 to 1995 and then a decline until 2014. For endurance, similar patterns were found in the two most comprehensive Chinese studies. The decline in flexibility is also evident in European countries. For agility, speed, balance, and coordination, the trend differs among populations.

Hand grip strength and dexterity function in children aged 6-12 years: A cross-sectional study

STUDY DESIGN

Cross-sectional and clinical measurement.

INTRODUCTION

Assessment of hand function considers an essential part in clinical practice.

PURPOSE OF THE STUDY

To develop normative values of hand grip strength and dexterity function for 6-12-year-old children in Saudi Arabia.

METHODS

Grip strength and dexterity function was measured in 525 children using Grip Track hand dynamometer (JTECH Medical, Midvale, UT, USA) and 9-hole pegboard test respectively.

RESULTS

The grip strength and dexterity function was improved as age progressed regardless of gender. Across all age groups, the hand grip strength of boys was significantly higher than girls for dominant hand (31.75 ± 10.33 vs 28.24 ± 9.35; P < .001) and nondominant hand (31.01 ± 10.27 vs 27.27 ± 9.30; P < .001). The girls performed slightly faster than boys for dominant hand (19.70 vs 20.68; P < .05) and nondominant hand (21.79 vs 23.46; P < .05). In general, girls completed a 9-HPT faster than boys in the 2 of 7 age groups: 11 years (9-HPT scores = 2.10 seconds; P < .01) and 12 years (9-HPT scores = 1.93 seconds; P < .01).

DISCUSSION

The overall patterns of hand grip strength and dexterity function observed in the present study are similar to the previous studies that established acceleration of grip strength with advanced age, and faster performance scores in older children than younger children in both genders.

CONCLUSIONS

Norms of hand grip strength and dexterity enable therapists to identify some developmental characteristics of hand function among Saudi children, determine the presence of impairment, and compare scores from children in different clinical settings.

LEVEL OF EVIDENCE

Not applicable.

Changes in Body Composition and Physical Fitness in Adolescents with Down Syndrome: The UP&DOWN Longitudinal Study

Background: Adolescents with Down syndrome (DS) demonstrate higher values of body composition and lower levels of physical fitness when compared with their peers with typically developing (TD) or their peers with intellectual disability but without DS. Objective: To examine, during a 2-year period, changes in indicators of body composition and physical fitness components in TD adolescents and adolescents with DS. Methods: Hundred adolescents with DS (64 males) aged 11-20 years old were matched by sex to 163 TD adolescents (108 males) aged 12-18. Indicators of body composition were determined by body mass index (BMI), waist circumference, waist-to-height ratio, skinfolds, and percentage of body fat (%BF). Components of physical fitness were assessed by the Assessing Level of Physical Activity (ALPHA) health-related fitness test battery for youth. Results: In the 2-year follow-up, significant (p < 0.05) decreases in BMI and increases in cardiorespiratory fitness and handgrip strength were seen for both groups; decreases in %BF were only seen for participants with DS; and increases in standing long jump were seen only for TD adolescents. Conclusions: Results indicate that during the 2-year study period, there were significant decreases in BMI and significant increases in handgrip strength and cardiorespiratory fitness in the TD group. For participants with DS, there was a significant decrease in %BF. However, participants with DS did not exhibit improvements in physical fitness.

Cardiorespiratory fitness and health-related quality of life in adolescents: A longitudinal analysis from the LabMed Physical Activity Study

OBJECTIVE

The purpose of this study was to examine the longitudinal associations between cardiorespiratory fitness and health-related quality of life (HRQoL) in a sample of adolescents, and to determine whether changes in cardiorespiratory fitness were associated with HRQoL over a 2-year follow-up.

METHODS

This is a longitudinal analysis with 571 Portuguese adolescents (274 boys and 297 girls) aged 12-18 years. HRQoL was measured with the Kidscreen-10 questionnaire; the 20 m shuttle-run was used to estimate cardiorespiratory fitness; socioeconomic status was assessed with the Family Affluence Scale; and pubertal stage was assessed with Tanner stages. Linear regression and analysis of covariance (ancovas) were used to examine the associations between cardiorespiratory fitness and HRQoL.

RESULTS

HRQoL decreased over a 2-year period both in boys and girls (P < .05). Moreover, girls at baseline and at follow-up reported significantly lower HRQoL values than boys (between subjects P < .001). After adjustments for potential confounders, regression analyses showed significant cross-sectional associations between cardiorespiratory fitness and HRQoL both at baseline (B = 0.095; P = .023) and at follow-up (B = 0.090; P = .012). ancova showed that adolescents whose cardiorespiratory fitness decreased over time exhibited lower scores of HRQoL at follow-up, compared to those with persistent high cardiorespiratory fitness; this held after adjustments for age, sex, socioeconomic status, and pubertal stage.

CONCLUSIONS

Changes in cardiorespiratory fitness during adolescence were associated with HRQoL over a 2-year period. This study suggests that improving cardiorespiratory fitness could be an important strategy in improving the HRQoL of adolescents.