Development of 1-mile walk tests to estimate aerobic fitness in children

To examine the reliability and validity of 1-mile walk tests for estimation of aerobic fitness (VO_2max) in 10- to 13-year-old children and to cross-validate previously published equations. Participants (n = 61) walked 1-mile on two different days. Self-reported physical activity, demographic variables, and aerobic fitness were used in multiple regression analyses. Eight models were developed with various combinations of predictors. The recommended model for fitness testing in schools was: VO_2max = 120.702 + (4.114 × Sex [F = 0, M = 1]) – (2.918 × 1-mile Walk Time [min]) – (2.841 × Age), R = .73, standard error of estimate = 6.36 mL·kg^?1·min^?1. Cross-validation of previously published equations demonstrated lower correlations with measured VO_2max than the newly developed walk tests. Evidence of reliability and validity for 1-mile walk tests to estimate VO_2max in young children was provided. The model that included 1-mile walk time, age, and sex may be appropriate for youth fitness testing in physical education, particularly for unmotivated or overweight young children.     

The multi-stage fitness test as a predictor of endurance fitness in wheelchair athletes

Abstract

The aims of this study were two-fold: (1) to consider the criterion-related validity of the multi-stage fitness test (MSFT) by comparing the predicted maximal oxygen uptake ([Vdot]O_2max) and distance travelled with peak oxygen uptake ([Vdot]O_2peak) measured using a wheelchair ergometer (n = 24); and (2) to assess the reliability of the MSFT in a sub-sample of wheelchair athletes (n = 10) measured on two occasions. Twenty-four trained male wheelchair basketball players (mean age 29 years, s = 6) took part in the study. All participants performed a continuous incremental wheelchair ergometer test to volitional exhaustion to determine [Vdot]O_2peak, and the MSFT on an indoor wooden basketball court. Mean ergometer [Vdot]O_2peak was 2.66 litres · min^?1 (s = 0.49) and peak heart rate was 188 beats · min^?1 (s = 10). The group mean MSFT distance travelled was 2056 m (s = 272) and mean peak heart rate was 186 beats · min^?1 (s = 11). Low to moderate correlations (ρ = 0.39 to 0.58; 95% confidence interval [CI]: ?0.02 to 0.69 and 0.23 to 0.80) were found between distance travelled in the MSFT and different expressions of wheelchair ergometer [Vdot]O_2peak. There was a mean bias of ?1.9 beats · min^?1 (95% CI: ?5.9 to 2.0) and standard error of measurement of 6.6 beats · min^?1 (95% CI: 5.4 to 8.8) between the ergometer and MSFT peak heart rates. A similar comparison of ergometer and predicted MSFT [Vdot]O_2peak values revealed a large mean systematic bias of 15.3 ml · kg^?1 · min^?1 (95% CI: 13.2 to 17.4) and standard error of measurement of 3.5 ml · kg^?1 · min^?1 (95% CI: 2.8 to 4.6). Small standard errors of measurement for MSFT distance travelled (86 m; 95% CI: 59 to 157) and MSFT peak heart rate (2.4 beats · min^?1; 95% CI: 1.7 to 4.5) suggest that these variables can be measured reliably. The results suggest that the multi-stage fitness test provides reliable data with this population, but does not fully reflect the aerobic capacity of wheelchair athletes directly.     

Worldwide variation in the performance of children and adolescents: An analysis of 109 studies of the 20-m shuttle run test in 37 countries

Abstract

This study is a meta-analysis of 109 reports of the performance of children and adolescents on the 20-m shuttle run test (20-mSRT). The studies were performed in 37 countries and included data on 418,026 children, tested between 1981 and 2003. Results were expressed as running speed (km · h^?1) at the final completed stage of the 20-mSRT. Raw data were combined with pseudodata using Monte Carlo simulation. The 20-mSRT performances were expressed as z-scores relative to all children of the same age and sex from all countries. An overall “performance index” was derived for each country as the average of the age- and sex-specific z-scores for all children from that country. Factorial analysis of variance was used to compare scores among countries and regions, and between boys and girls of the same age. There was wide and significant (P < 0.0001) global variability in the performance of children. The best performing children were from the Northern European countries Estonia, Iceland, Lithuania, and Finland (0.6 – 0.9 standard deviations above the global average). The worst performing children were from Singapore, Brazil, USA, Italy, Portugal, and Greece (0.4 – 0.9 standard deviations below the global average). There is evidence that performance was negatively related to being overweight, as well as to a country's average temperature.     

Validity of equations for estimating aerobic fitness in Mexican youth

The purpose of this study was to evaluate the validity of prediction equations for estimating maximal oxygen uptake (VO_2peak) based on the PACER test and different adiposity indicators in Mexican youth. A convenience sample of youth aged 9–18 years from schools in Mexico City was recruited. VO_2peak was evaluated with a laboratory exercise test on a treadmill and using a gas analyser and with the 20-m PACER test guidelines. The sample was randomly divided to develop new equations (n = 220) and to evaluate their validity (n = 106). Prediction equations of VO_2peak were developed using multiple linear regression models. The adiposity indicators were BMI, waist circumference and body fat. The validity of the new and previously published equations was evaluated based on linear regression models, intra-class coefficient, Akaike’s information criterion, mean absolute percentage error and Bland-Altman graphs. Equations with waist circumference and body fat performed better than those with BMI and without any anthropometric indicator. The accuracy of the developed equations (R² = 57.0%–59.50%) was higher than that of previously published equations (R² = 24.1%–56.0%). The new equations had lower bias in estimating VO_2peak. In Mexican youth, the estimation of VO_2peak from the 20-m PACER test is more accurate after including waist circumference or body fat than with BMI.     

Respiratory responses and rating of perceived exertion of severely obese adolescents during continuous and intermittent graded walking protocols: Application to cardiorespiratory field tests

ABSTRACT

During 20 m shuttle tests, obese adolescents may have difficulty achieving maximum cardiorespiratory performance due to the presence of braking-relaunch phases (BRP). Nineteen obese adolescents aged 15.2 ± 1.5 years (body mass index [BMI] = 39.7 ± 5.9 kg.m^?2) performed three graded walking exercises on a 50 m track at speeds between 3 and 6 km/h: a continuous-straight-line protocol (C), a continuous protocol that required turning back every 30 sec (C-BRP) and an intermittent protocol that consisted of successively walking then resting for 15 sec (15–15). Oxygen uptake (VO₂), aerobic cost of walking (Cw), ventilation (VE) and rating of perceived exertion (RPE) were measured at each stage during the protocols. During C-BRP, the responses were not significantly higher compared with C (p > 0.30). During 15–15, the VO₂, Cw and VE were ~ 15 to 25% lower than during C beginning at 4 km/h (p < 0.05). In obese adolescents, the respiratory impact of sudden directional changes during the 20 m shuttle-type test appeared to be minor at walking speeds. During the 15–15 test, the intensity increases more progressively, and this design may encourage obese adolescents to walk further than during a continuous test.     

20-MST监测心肺功能变化的有效性及敏感性研究

目的:探讨20-MST监测普通大学生心肺功能变化的有效性及对运动训练的敏感性。方法:以32名男性大学生(实验组、对照组各16名)为研究对象,对实验组学生进行8周的有氧耐力训练干预,在实验前后分别测定VO2max、20-MST、库博12min跑、台阶试验四项指标,并对检测结果进行分析比较。结果:20-MST在实验前后与VO2max、12min跑成绩高度相关,与台阶指数低度相关;实验后,各指标均有显著增长,20-MST的增量最明显。结论:20-MST是一种间接评价心肺功能、判断训练效果的有效方法,它对评价运动训练引起心肺功能适应性变化的敏感性高于VO2max。     

20-MST对评价心肺功能的横向有效性研究

以体育专业学生、非体育专业学生为研究对象,从横向的角度研究20-MST对反映不同训练水平受试者心肺功能的有效性,以期为推广20-MST提供基础实验依据。     

从我国文化心理的角度对青少年体质下降问题的探究

从中国人“自我”观、“重文轻武”思想、“权威思维”、“实用思维”等文化心理特质对我国青少年体质下降问题进行探究,并将这些特质贯穿于社会、家庭、学校、青少年自身四个方面进行分析,以期获得对这一问题的新认识.     

Sedentary time and vigorous physical activity are independently associated with cardiorespiratory fitness in middle school youth

Abstract

The purpose of this cross-sectional study was to examine the relationship between objectively measured physical activity, sedentary time, and cardiorespiratory fitness in a diverse sample of youth. Participants were recruited from three middle schools and completed assessments of height, weight, cardiorespiratory fitness, and wore an accelerometer for a minimum of four days. Hierarchical general linear models controlling for age, body mass index (BMI) percentile, and sex were used to evaluate the association of time (minutes per day) spent sedentary, and in moderate physical activity and vigorous physical activity with cardiorespiratory fitness (i.e., heart rate response [beats per minute], dependent variable). Results indicated age (β = –0.16, P < 0.05), BMI percentile (β = 0.33, P <0.05), being male (β = 0.17, P < 0.05), sedentary time (β = 0.11, P <0.05), moderate (β = –0.03, P > 0.05) and vigorous (β = –0.22, P < 0.05) physical activity explained 29% of the variance in cardiorespiratory fitness. Evaluation of fitness among high sedentary/high vigorous, high sedentary/low vigorous, low sedentary/low vigorous, and low sedentary/high vigorous groups (defined by the median split) showed that high levels of vigorous activity removed the detrimental effect of high levels of sedentary time on cardiorespiratory fitness. These analyses suggest that the negative impact of sedentary time can be mitigated by engaging in vigorous activity.     

Influence of carbohydrate mouth rinsing on running and jumping performance during early morning soccer scrimmaging

Carbohydrate mouth rinse (CMR) is a novel method proposed to enhance endurance performance lasting ≤ 60 min. The current study examined the influence of CMR on anaerobic performance tasks in 11 collegiate female soccer players after an overnight fast. Athletes completed two experimental sessions, during which carbohydrate (CHO; 6% maltodextrin) or taste- and colour-matched placebo (PLA) mouth-rinse solutions were administered in a counterbalanced, double-blinded design. Three rounds of a 5-min scrimmage bout and series of performance tests including a single countermovement vertical jump (1VJ), a set of four consecutive vertical jumps, a 72-m shuttle run (SR72) and 18-m sprint comprised each trial. Thirst sensation (TS), session TS, ratings of perceived exertion (RPE) and session RPE were assessed as secondary outcomes. The first SR72 approached significance (p = 0.069), but no significant between-trials differences were observed for any of the mean performance tasks. The highest 1VJ scores did not differ for the first (CHO = 47.3 ± 3.4, PLA = 47.7 ± 3.5 cm; p = 0.43), second (CHO = 48.0 ± 4.1, PLA = 47.9 ± 3.5 cm; p = 0.82) or third bout (CHO = 47.4 ± 3.9, PLA = 48.1 ± 3.9 cm; p = 0.26). TS approached significance (p = 0.053) during the first bout. No significant differences (p > 0.05) were found for any of the perceptual variables. Current results fail to support ergogenic influence of CMR on anaerobic performance tasks in collegiate female athletes.     

20m逐级往返跑评价心肺机能的场地适应性

通过四类场地上用20-MST预测最大吸氧量的重测信度,评估20-MST评价心肺功能的场地适应性。受试为韩山师范学院的大学生自愿者152人,其中男生88人,女生64人。每名受试分别在水泥路面、煤渣跑道、三合土地面和塑胶跑道上完成一次20-MST,隔天一次。结果表明,四类场地上用20-MST预测的最大吸氧量重测信度在0．889至0．943之间,预测值之间没有显著性差异。20-MST评价心肺机能具有较好的场地适应性。     

Classes of developmental trajectories of body mass index: Differences in motor competence and cardiorespiratory fitness

ABSTRACT

The purpose was to identify classes of different developmental trajectories of BMI and testing them for differences in motor competence (MC) and cardiorespiratory fitness (CRF), in children and adolescents (4 to 13 years of age). This was a 5 years’ longitudinal study with six cohorts. One hundred and forty-seven children (69 girls) divided into six cohorts participated. At baseline, the youngest and the oldest cohorts had 4 and 11 years of age, respectively. Height and weight were assessed, and BMI was calculated. MC was assessed with KTK and TGMD-2, and CRF was assessed with one-mile run/walk. Developmental trajectories of BMI were identified using latent class linear-mixed modelling. Latent class membership was explained according to covariates of MC and CRF. Two meaningful classes were identified. Class 1 (78.92% of the participants) showed lower initial BMI and a lower slope compared to class 2 (21.08% of the participants) (all ps < 0.001). Class membership only predicted trajectories in motor coordination, with children in class 1 having a better development.

In conclusion, this study identified two meaningful trajectories for children based on their BMI development across five time points. In line with previous research, children with slower increasing BMI showed better motor coordination improvements.     

Inter-participant variability in daily physical activity and sedentary time among male youth sport footballers: independent associations with indicators of adiposity and cardiorespiratory fitness

Participation in youth sport is assumed to promote and contribute towards more physically active lifestyles among children and adolescents. The aim of this study was to examine inter-participant variability in objectively measured habitual physical activity (PA) behaviours and sedentary time among youth sport participants and their implications for health. One-hundred-and-eighteen male youth sport footballers (Mean ± s = 11.72 ± 1.60) wore a GT3X accelerometer for 7 days. Average daily PA [min · day^?1, in light (LPA), moderate (MPA), vigorous (VPA) and combined moderate-to-vigorous (MVPA)] and sedentary time were calculated. Participants’ body mass index adjusted for age and sex (BMI–standard deviation score), per cent body fat (BF%), waist circumference and cardiorespiratory fitness were assessed. Results revealed that variability in daily PA behaviours and sedentary time (min · day^?1) was associated with BMI–standard deviation score [VPA (?), MVPA (?)], BF% [sedentary time (+), VPA (?), MVPA (?)], waist circumference [sedentary time (+), LPA (?)] and cardiorespiratory fitness [sedentary time (?), MPA (+), VPA (+), MVPA (+)]. Whilst sedentary time and MVPA were not related to health outcomes independent of one another, associations with markers of adiposity and cardiorespiratory fitness were stronger for sedentary time. Sedentary time was also significantly positively related to waist circumference independent of VPA. Results demonstrate inter-participant variability in habitual PA and sedentary time among youth sport participants which holds implications for their health. Thus, promoting PA and, in particular, reducing sedentary time may contribute towards the prevention of adverse health consequences associated with a physically inactive lifestyle for children and adolescents active in the youth sport context.     

健身消费者消费行为影响因素的研究——来自南京市商业性健身俱乐部消费者的调查

在问卷调查和专家咨询的基础上,以南京市健身俱乐部的消费者为研究对象,运用R型因子分析方法,确立了影响健身消费者消费行为的六大主因素,分别是宣传、价格、环境、服务、品牌和产品因素。从消费行为学和消费心理学角度对各个影响因素进行探讨和分析,提出相关建议。     

Exploring overweight and obesity beyond body mass index: A body composition analysis in people with and without patellofemoral pain

BackgroundWe compared body mass index (BMI), body fat, and skeletal muscle mass between (1) a mixed-sex nonathletic cohort of people with patellofemoral pain (PFP) and pain-free people, and (2) a nonathletic cohort of people with PFP and pain-free people subgrouped by sex (i.e., men and women with PFP vs. pain-free men and women).MethodsThis cross-sectional study included 114 people with PFP (71 women, 43 men) and 54 pain-free controls (32 women, 22 men). All participants attended a single testing session to assess body composition measures, which included BMI, percentage of body fat (%BF_Bioimpedance), and skeletal muscle mass (both assessed by bioelectrical impedance analysis), and percentage of body fat (%BF_Skinfold) (assessed by skinfold caliper analysis). A one-way univariate analysis of covariance (age and physical activity levels as covariates) was used to compare body composition measures between groups (i.e., PFP vs. pain-free group; women with PFP vs. pain-free women; men with PFP vs. pain-free men).ResultsWomen with PFP presented significantly higher BMI, %BF_Bioimpedance, and %BF_Skinfold, and lower skeletal muscle mass compared to pain-free women (p ≤ 0.04; effect size : ‒0.47 to 0.85). Men with PFP and men and women combined had no differences in BMI, %BF_Bioimpedance, %BF_Skinfold, and skeletal muscle mass compared to their respective pain-free groups (p > 0.05).ConclusionOur findings indicate that BMI and body composition measures should be considered as part of the evaluation and management of people with PFP, especially in women, who have demonstrated higher BMI and body fat and lower skeletal muscle mass compared to pain-free controls. Future studies should not assess body composition measures in a mixed-sex population without distinguishing men participants from women participants.     

Temporal trends in the sit-ups performance of 9,939,289 children and adolescents between 1964 and 2017

ABSTRACT

We estimated international/national temporal trends in sit-ups performance for children and adolescents, and examined relationships between national trends in sit-ups performance and national trends in health-related/sociodemographic indicators. Data were obtained by systematically searching studies reporting on temporal trends in sit-ups performance for apparently healthy 9–17 year-olds, and by examining nationally representative fitness datasets. Trends at the country-sex-age level were estimated by sample-weighted regression models relating the testing year to mean sit-ups performance. International/national trends were estimated by a post-stratified population-weighting procedure. Pearson’s correlations quantified relationships between national trends in sit-ups performance and national trends in health-related/sociodemographic indicators. A total of 9,939,289 children and adolescents from 31 countries/special administrative regions between 1964 and 2017 collectively showed a large improvement 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. Trends differed between countries, with national trends in vigorous physical activity a strong, positive correlate of national trends in sit-ups performance. More sit-ups data are needed from low- and middle-income countries to better monitor trends in muscular fitness.     

武汉体育学院学生身体素质测试指标、方法和结果研究

研究分析武汉体育学院学生身体素质测试指标、方法、过程与结果。结合体育院校学生特点,对学生身体素质指标进行了测试,并就选择学生身体素质测试的原则、依据、测试指标的构建和方法的确立等进行探讨。制订身体素质测试指标和评价标准,结果表明:学生身体素质测试指标与评价标准符合在校学生身体素质的实际,达到了预期的目的与效果。     

Prediction of maximal oxygen uptake from a 20-m shuttle run as measured directly in runners and squash players

Abstract

The aim of this study was to assess the validity of the multistage shuttle run test in predicting maximal oxygen uptake (VO ₂ max) in athletes trained in sports with different physical demands. Over a 14-day period, 10 male long-distance runners (continuous high-intensity exercise) and 10 male squash players (intermittent high-intensity exercise) performed, in random order, the multistage shuttle run test and a maximal treadmill protocol of increasing elevation which elicited VO ₂ max. Compared with direct measurement of VO ₂ max, the shuttle run test significantly underpredicted the VO ₂ max of the group of runners (n=10; P<0.01) and of the athletes as a whole (n=20; P<0.01). The correlation (r) between VO ₂ max determined by the shuttle run test and by the treadmill protocol was 0.61 (P<0.05) for the squash players, 0.71 (P<0.05) for the runners and 0.67 (P<0.01) for the athletes as a whole. As the subjects represented athletes trained specifically in sports with different physical demands, this may explain why the correlations between the shuttle run test and direct measurement of VO ₂ max are less robust than those reported in previous studies. Furthermore, our results indicate that there are sport-specific differences when predicting VO ₂ max from the multistage shuttle run test.     

Feasibility and concurrent validity of a cardiorespiratory fitness test based on the adaptation of the original 20 m shuttle run: The 20 m shuttle run with music

ABSTRACT

The purpose was to examine the feasibility of the 20m shuttle run test with music and to test its concurrent validity with the original 20m shuttle run test. A total of 386 adolescents (14.5±1.6 years old, 48.9% boys) participated in our study. A self-reported questionnaire was used to assess student’s perception about the 20m shuttle run test with music and the original and to assess perceived exertion. Participants performed randomly the 20m shuttle run test with music and original two weeks apart. Average and maximum heart rate were monitored with heart rate monitors. The 20m shuttle run with music was a feasible test for measuring cardiorespiratory fitness in adolescents. The concurrent validity showed mean differences of 5.1±14.6 for shuttles, 0.3±0.8 km/h for speed, 0.5±4.1 for stages, and 1.5±4.1 for VO2max (all p<0.001) in favour of the 20m shuttle run with music vs. the original 20m shuttle run test. Mean difference for the rating of perceived exertion was 0.4±2.5 points (p=0.003). No significant difference was found between boys and girls. In conclusion, the 20mSRT-music is feasible and presents a good concurrent validity in adolescents, independently of the sex and it will be an alternative and good approach to assess cardiorespiratory fitness.