Temporal trends in muscular fitness of English 10-year-olds 1998-2014: an allometric approach

Objectives To identify temporal trends in muscular fitness of English children using allometric scaling for height and weight to adjust for the influence of body size. Design Repeated cross-sectional study. Methods We measured; height, weight, standing broad-jump, handgrip, sit-ups and bent-arm hang in 10-year-old boys and girls from Chelmsford, England in: 2014 (n = 306), 2008 (n = 304) and 1998 (n = 310). Physical activity was (PAQ-C) was assessed in 2008 and 2014. Muscular fitness was allometrically scaled for height and weight. We assessed temporal trends using General Linear Models (fixed factors: wave and sex) and reported effect sizes using partial eta squared (ηP²). We compared percentage change per year 1998-2008 with 2008-2014. Results Ten-year-olds in 2014 were taller and heavier than in 2008 and 1998 but there were no differences in BMI. Compared with 2008, physical activity was lower in boys (ηP² = 0.012) and girls (ηP² = 0.27) assessed in 2014. There were significant main effects of wave for handgrip (ηP² = 0.060), sit-ups (ηP² = 0.120) and bent-arm hang (ηP² = 0.204). Pairwise comparisons showed muscular fitness of both sexes was significantly lower in 2014 than in 1998. From 2008 to 2014 percent change per year in handgrip (1.6%) and sit-ups (3.9%) were greater than for the preceding decade (handgrip 0.6%, sit-ups 2.6%). Conclusions Downward temporal trends in muscular fitness appear independent of secular changes in body size. We found a decrease in self-reported physical activity concurrent with the accelerated declines in fitness from 2008 to 2014. These findings suggest the declines in children are not engaging in physical activities which support development of muscular fitness

Temporal Trends In The Grip Strength Of Children And Adolescents

Objective: To estimate national and international temporal trends in the handgrip strength of children and adolescents, and to examine relationships between trends in handgrip strength and trends in health-related and sociodemographic indicators. Methods: Data were obtained in two ways: (a) through a systematic electronic database search for studies reporting on temporal trends in the handgrip strength of apparently healthy 9–17-year-olds, (b) pearling reference lists, topical systematic reviews and personal libraries, and (c) by examining large national fitness datasets suitable to temporal trends analysis. Sample-weighted temporal trends were estimated using best-fitting regression models relating the year of testing to mean handgrip strength. Post-stratified population-weighted mean changes in percent and standardized handgrip strength were estimated. Pearson’s correlations were used to quantify relationships between linear trends in handgrip strength and linear trends in health-related and sociodemographic indicators. Results: Trend data from 22 studies/datasets representing 2,216,589 children and adolescents from 13 high-, five upper-middle-, and one low-income country collectively showed a moderate improvement in mean handgrip strength of 19.4% (95%CI: 18.4 to 20.4) or 3.8% per decade (95%CI: 3.6 to 4.0) between 1967 and 2017. The international rate of improvement in handgrip strength increased over time, doubling since the 1960s and 1970s. Improvements were larger for children (9–12 years) than adolescents (13–17 years) and similar for boys and girls. Trends differed in magnitude and direction between countries, with most experiencing improvements. Trends in handgrip strength were negligibly-to-moderately related to trends in health-related and sociodemographic indicators. Conclusions: There has been a meaningful improvement in the handgrip strength of children and adolescents since 1967, which has progressively increased in magnitude over time and is suggestive of a corresponding improvement in muscle and bone health. There is a need for improved international surveillance of handgrip strength, especially in children and adolescents from low- and middle-income countries, given the meaningful associations between handgrip strength and health-related outcomes

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 trends in handgrip strength and 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 to 20.4) or 3.8% per decade (95%CI: 3.6 to 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 trends in handgrip strength and 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

A Systematic Analysis Of Temporal Trends In The Sit-Ups Performance Of 9,939,289 Children And Adolescents Between 1964 And 2017 Representing 31 Countries

Objective: To estimate national and international temporal trends in the sit-ups performance of children and adolescents, and to examine relationships between trends in sit-ups performance and trends in health-related and sociodemographic indicators. Methods: Data were obtained in three ways: (a) through a systematic electronic database search of studies reporting on temporal trends in the handgrip strength of apparently healthy 9–17 year-olds, (b) by pearling reference lists, topical systematic reviews and personal libraries, and (c) by examining large country-level fitness datasets suitable to temporal trends analysis. Sample-weighted temporal trends (expressed as percent and standardized trends) were estimated at the country-sex-age level using best-fitting regression models relating the year of testing to mean sit-ups performance. International and national trends were estimated by post-stratified population-weighted mean changes standardized to the year 2000. Pearson’s correlations were used to quantify relationships between linear trends in sit-ups performance and linear trends in health-related and sociodemographic indicators. Results: Trend data from 27 studies/datasets representing 9,939,289 children and adolescents representing 31 countries (25 high-, 5 upper-middle-, and 1 low-income countries) between 1964 and 2017 collectively showed a large improvement in mean sit- ups performance of 38.4% (95%CI: 36.8 to 40.0) or 7.1% per decade (95%CI: 6.8 to 7.4). Large international improvements were experienced by all age and sex groups, with the rate of improvement slowing from 1964 to 2000, stabilizing near zero until 2010, before declining thereafter. Trends differed in magnitude and direction between countries, with most experiencing improvements. Trends in vigorous physical activity levels were a strong positive correlate of trends in sit-ups performance. Conclusions: There has been a large international improvement in children’s sit-ups performance since 1967, which has progressively diminished in magnitude over time. Sit- ups data are needed from children in low-income and middle-income countries in order to better monitor national and international trends in muscular fitness

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

This article belongs to the Special Issue Health Promotion in Children and Adolescents through Sport and Physical Activities—2nd Edition[Abstract] 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

Temporal Trends In The Standing Broad Jump Test Performance Of United States Children And Adolescents

Muscular fitness is a very important indicator of health. Using a systematic review strategy, the aim of this study was to estimate the temporal trends in broad jump performance of United States youth. Broad jump data on apparently healthy United States youth (aged 10–17 years) were located through a systematic electronic database search and by pearling reference lists, topical systematic reviews and personal libraries. Sample-weighted temporal trends (expressed as percent and standardized trends) were estimated for separate age-sex groups using best-fitting regression models relating the year of testing to mean jump performance. Mean trends standardized to the year 1985 were calculated using a post-stratified population-weighting procedure. Data from 12 studies comprising 16 unique datasets were used to estimate trends for 65,527 United States youth between 1911 and 1990. Collectively, there was a small improvement in broad jump performance of 7.9% (95%CI: 7.1 to 8.6) or 1.0% per decade (95%CI: 0.9 to 1.1). Improvements were observed for all sex and age groups, with improvements substantially larger for girls than for boys, and similar for children (10–12 years) and adolescents (13–17 years). Improvements in broad jump performance were not always uniform across time, with steady improvements observed for boys, a diminishing in the rate of improvement observed for girls and adolescents, and an increasing rate of improvement observed for children. Given that muscular fitness is a good marker of health, and that the broad jump is a practical, feasible, and scalable marker of muscular fitness, then the broad jump should be routinely assessed to screen and monitor the health and muscular fitness of United States youth

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

Strength and conditioning in schools: a strategy to optimise health, fitness and physical activity in youths

Editoria

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 (VO(2)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.Peer reviewe