Test–retest reliability of a battery of field-based health-related fitness measures for adolescents

Abstract

The main aim of this study was to determine the test–retest reliability of existing tests of health-related fitness. Participants (mean age 14.8 years, s = 0.4) were 42 boys and 26 girls who completed the study assessments on two occasions separated by one week. The following tests were conducted: bioelectrical impedance analysis (BIA) to calculate percent body fat, leg dynamometer, 90° push-up, 7-stage sit-up, and wall squat tests. Intra-class correlation (ICC), paired samples t-tests, and typical error expressed as a coefficient of variation were calculated. The mean percent body fat intra-class correlation coefficient was similar for boys (ICC = 0.95) and girls (ICC = 0.93), but the mean coefficient of variation was considerably higher for boys than girls (22.2% vs. 12.2%). The boys' coefficients of variation for the tests of muscular fitness ranged from 9.0% for the leg dynamometer test to 26.5% for the timed wall squat test. The girls' coefficients of variation ranged from 17.1% for the sit-up test to 21.4% for the push-up test. Although the BIA machine produced reliable estimates of percent body fat, the tests of muscular fitness resulted in high systematic error, suggesting that these measures may require an extensive familiarization phase before the results can be considered reliable.     

Exercise training increases the S-Klotho plasma levels in sedentary middle-aged adults: A randomised controlled trial. The FIT-AGEING study

ABSTRACT

This study aimed to investigate the effects of different training modalities on the soluble Klotho (S-Klotho) plasma levels in sedentary middle-aged adults. A total of 74 middle-aged adults (53.4 ± 5.0 years old; 52.7% women) were enrolled in the FIT-AGEING study. We conducted a 12-week randomised controlled trial. The participants were randomly assigned to 4 different groups: (i) a control group (no exercise), (ii) a physical activity recommendation from the World Health Organization group (PAR), (iii) a high intensity interval training group (HIIT), and (iv) a high intensity interval training group adding whole-body electromyostimulation training group (HIIT-EMS). S-Klotho plasma levels, anthropometric measurements, and body composition variables were measured before and after the intervention programme. All exercise training modalities induced an increase in the S-Klotho plasma levels (all P ≤ 0.019) without statistical differences between them (all P ≥ 0.696). We found a positive association between changes in lean mass index and changes in the S-Klotho plasma levels, whereas a negative association was reported between changes in fat mass outcomes and changes in the S-Klotho plasma levels after our intervention study. In conclusion, our results suggest that the link between exercise training and the increase in S-Klotho plasma levels could be mediated by a decrease of fat mass and an increase of lean mass.     

Bone mineral density and lean mass asymmetries are greater in cyclists than non-cyclists

ABSTRACT

Cyclists may be at greater risk of developing asymmetrical force and motion patterns than other ground-based athletes. However, functional asymmetries during cycling tend to be highly variable, making them difficult to assess. Dual-energy x-ray absorptiometry (DXA) measurements of areal bone mineral density (aBMD) and lean mass (LM) in the lower limbs may be a more sensitive and consistent method to identify asymmetries in cyclists. The goal of this study was to determine if competitive cyclists have greater levels of asymmetries in the lower body compared to non-cyclists using DXA. A secondary aim was to determine if aBMD and LM asymmetries change over the road cycling season. 17 competitive cyclists and 21 non-cyclist, healthy controls underwent DXA scans. Lower-body asymmetries were greater in cyclists compared to non-cyclists in aBMD and LM for all lower limb segments. However, these asymmetries did not tend to consistently favour a particular side, except for the pelvis having more LM on the dominant side. The were no longitudinal changes in aBMD or LM in the cyclists. Asymmetry analysis via DXA provides evidence that although functional asymmetries during cycling are variable, cyclists have increased lower body LM and aBMD asymmetries compared to non-cyclists.     

Matching of Male and Female Subjects Using VO2 max

Abstract

We compared cardiorespiratory responses to exercise on an underwater treadmill (UTM) and land treadmill (LTM) and derived an equation to estimate oxygen consumption (VO₂) during UTM exercise. Fifty-five men and women completed one LTM and five UTM exercise sessions on separate days. The UTM sessions consisted of chest-deep immersion, with 0, 25, 50, 75, and 100% water-jet resistance. All session treadmill velocities increased every 3 min from 53.6 to 187.8 m·min^-1. Cardiorespiratory responses were similar between LTM and UTM when jet resistance for UTM was ≥ 50%. Using multiple regression analysis, weight-relative VO₂ could be estimated as: VO₂ (mLO₂·kg^-1·min^-1) = 0.19248 · height (cm) + 0.17422 · jet resistance (% max) + 0.14092 · velocity (m·min^-1) - 0.12794 · weight (kg) - 27.82849, R²= .82. Our data indicate that similar LTM and UTM cardiorespiratory responses are achievable, and we provide a reasonable estimate of UTM VO₂.     

低氧训练过程中大鼠体重及能量代谢的变化

目的：研究低氧训练过程中大鼠体重、体成分、能量摄入及静息代谢率的变化，初步探讨低氧训练过程中大鼠体重变化与能量代谢变化间关系。方法：经过适应性训练筛选出的50只SD大鼠平均分为5组，保证每组大鼠体重基本一致，随机分为常氧安静组、常氧限食组、常氧训练组、低氧安静组、低氧训练组。训练组大鼠采用水平动物跑台进行耐力训练6周。试验期间每周称量大鼠体重，每3天称量一次大鼠食物摄入量。试验前、试验1周、3周、5周末测定大鼠静息代谢率，试验后处死大鼠并剥离其肾周、腹股沟脂肪及腓肠肌，称量其重量。结果：低氧训练组大鼠体重增幅除在第6周末与常氧训练组无显著性差异外，均显著性低于其他试验组，试验前3周其体重出现负增长。试验后低氧训练组大鼠肾周及腹股沟脂肪总含量显著低于其他试验组，而腓肠肌重量与其他组无显著性差异。低氧训练组大鼠试验期间总食物摄入量较其他各组大鼠低，尤其在前3周。低氧训练组大鼠静息代谢率先上升而后逐渐下降，至试验3周末时仍高于试验前值，试验5周末时降至低于试验前值（差异不显著），而除低氧安静组外的其他组大鼠静息代谢率则持续下降，至试验5周末时均显著性低于试验前水平。结论：从减缓体重增加幅度及对体成分的影响角度看，低氧训练减体重的效果优于限制饮食、耐力训练及低氧暴露。低氧训练过程中食物摄入量减少及静息代谢率增加可能是大鼠体重增长减缓的原因。     

补充糖+乳清蛋白对业余足球运动员运动能力影响的研究

目的:普通高校业余足球队运动员在备战广东省第7届大学生运动会训练期间,观察补充低聚糖 乳清蛋白(4:1)饮料对体成分、部分血生化指标和运动能力的影响。方法:16名男性普通高校业余足球队运动员随机分成对照组(n=8)和实验组(n=8),进行为期12周的实验,实验组运动员在每天训练前即刻、训练后1h内和临睡前,择时补充糖 乳清蛋白,对照组运动员则补充纯净水,实验前后分别进行体成分、血生化指标和体能测试,并统计整个大运会每场比赛结果。结果:足球运动员补充低聚糖加乳清蛋白能有效地保护红细胞功能,预防血红蛋白水平的下降,同时可提高体能、促进疲劳的消除,对维持肌肉微结构有积极作用。     

浅谈比况表达式中的语音停顿现象

中间有语音停顿，书面上用标点符号隔开的比况表达式是一种比较特殊的表达形式。本文通过对比的方式，从表达式的词语功能、表达功能、句法功能、内部关系和结构形式几个方面对其进行初步探讨。     

论写作之前学生情感的培养

学生作文之前,教师要在中文教学中培养其情感因素.不过,只有对当今作文的时代特色、"语""文"分离的现状和"以人为本"的教学理念有了更为详尽的认识,才能达到这一目的.     

浙江省常绿阔叶林的物种组成和群落物种多样性--以若干保护较好的地区为例

常绿阔叶林是浙江省的地带性植被,在维护区域生态系统功能等方面起着重要作用.综合该省若干保护较好地区的样方资料,采用多项指标进行了物种多样性的测度,表明浙江省保护较好的常绿阔叶林区域是我国中亚热带东部物种多样性较高的区域之一,自然环境、群落小环境和人为干扰是影响多样性大小的重要因素,常绿阔叶林中的珍稀物种需要给予更多的关注与保护.     

论重点高中快速作文教学中的快速思维训练

从可能性、必要性、原则性三个方面论述了快速思维训练应是重点高中快速作文教学的首要因素，快速思维训练不仅是快速作文教学的重要手段，也是快速作文教学的目的。