Exercise and bone     

《European Journal of Sport Science》2013,13(3):141-144

Abstract

The aim of this study was to examine the interrelationship between aerobic fitness, body composition, and physical activity in 9- and 15-year-olds. The 270 participants were randomly selected from 18 primary and secondary schools in Iceland. Aerobic fitness was assessed by a graded exercise test on a bicycle ergometer. Body composition was estimated via: logarithm of sum of four skinfolds (log_e skinfolds), waist adjusted for height, and body mass index (BMI). Physical activity was measured with Actigraph activity monitors using total activity each day as the physical activity variable. Aerobic fitness was chosen as the primary outcome variable, body composition as the secondary variable, and physical activity as the tertiary variable. All the full models explained a similar proportion of fitness variance for both age groups (45–65%). Among the 15-year-olds, log_e skinfolds explained a significantly larger proportion of the fitness variance (54%) than waist adjusted for height (29%) and BMI (15%), but all the body composition variables explained a similar proportion of the fitness variance (35–42%) among the 9-year-olds. Physical activity explained a smaller proportion (0%) of the unadjusted variance in fitness for the 9-year-olds than for the 15-year-olds (19%). This group difference became non-significant (0% vs. 4%) when adjusting for log_e skinfolds but remained significant when controlling for waist adjusted for height (0% vs. 15%) and BMI (0% vs. 18%). Gender differences in aerobic fitness after puberty can largely be explained by gender differences in log_e skinfolds and physical activity. In conclusion, the interrelationship between fitness, body composition, physical activity, and gender is not the same among 9- and 15-year-olds.  相似文献   

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

Victoria L. Goosey-Tolfrey  Keith Tolfrey 《Journal of sports sciences》2013,31(5):511-517

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.  相似文献   

我国高校竞技健美操男单成套难度动作分析     

张中印  马凌波  周燕  熊德良  秦勇 《哈尔滨体育学院学报》2013,(2):74-79,96

采用文献资料、专家访谈、数理统计、录像分析等方法对2010年健美操世锦赛、2011年全国健美操锦标赛精英组男单决赛前6名成套的难度动作编排体系进行对比分析,探析两者之间的差异、差距,为我国男单成套创编提供参考。研究发现：我国男单成套中难度动作的选择比较单一,重复率高;顺序安排无规律;动作失误率高,部分难度动作完成质量较差;部分运动员完成高难度动作的能力有所欠缺,D组动作的稳定性有待加强。  相似文献   

A pilot scale trickling filter with pebble gravel as media and its performance to remove chemical oxygen demand from synthetic brewery wastewater     

Haimanot Habte Lemji  Hartmut Eckstädt 《Journal of Zhejiang University. Science. B》2013,14(10):924-933

Evaluating the performance of a biotrickling filter for the treatment of wastewaters produced by a company manufacturing beer was the aim of this study. A pilot scale trickling filter filled with gravel was used as the experimental biofilter. Pilot scale plant experiments were made to evaluate the performance of the trickling filter aerobic and anaerobic biofilm systems for removal of chemical oxygen demand (COD) and nutrients from synthetic brewery wastewater. Performance evaluation data of the trickling filter were generated under different experimental conditions. The trickling filter had an average efficiency of (86.81±6.95)% as the hydraulic loading rate increased from 4.0 to 6.4 m³/(m²·d). Various COD concentrations were used to adjust organic loading rates from 1.5 to 4.5 kg COD/(m³·d). An average COD removal efficiency of (85.10±6.40)% was achieved in all wastewater concentrations at a hydraulic loading of 6.4 m³/(m²·d). The results lead to a design organic load of 1.5 kg COD/(m³·d) to reach an effluent COD in the range of 50–120 mg/L. As can be concluded from the results of this study, organic substances in brewery wastewater can be handled in a cost-effective and environmentally friendly manner using the gravel-filled trickling filter.  相似文献   

对我院健美操普修教学大纲及其内容改革的初步研究     

王美  杨琬  刘建兵 《首都体育学院学报》2000,(2)

我院根据社会发展和教学改革的需要 ,于 1999年制订并执行了新的健美操教学大纲。本文对新健美操教学大纲的制订依据、指导思想及大纲的结构、内容进行了研究 ,提出了执行新大纲应注意的问题和相应的对策。  相似文献   

有氧健身操和力量训练对年轻超重和肥胖男性体能与血液改变的对比研究*     

谢佳辉  方〓奇   《广州体育学院学报》2019,(5):103-106

国内肥胖和超重现象日趋严重，运动减肥中常用的两种方法：有氧健身操和力量练习方法，这两种训练方式如何改变年轻超重和肥胖男性的身体形态和机能？文章试图来给予正在利用这两类运动方式健身和减肥的年轻超重或者肥胖者一些科学建议，从而能够根据自身身体状态和需求来科学健身。研究方法：9周训练时间，分3组平行进行，分别为有氧健身操组、力量训练组和对照组，训练一般选在下午5点进行，每次训练90min，5次/周。实验前后分别测试受试者的BMI，体脂率，最大摄氧量，耐力，握力和弹跳力，以及血清中的白细胞介素1β(IL-1β)和6(IL-6)，以及肿瘤坏死因子α(TNF-α)，并统计分析实验数据，t检验实验前后和组间的差异。实验结果：有氧健身操和力量训练都能减少年轻超重和肥胖男性的BMI和体脂率，并增加肌肉量、握力和弹跳力，但有氧健身操改善受训者的心肺功能（最大摄氧量和耐力）的能力要强于力量训练。对于血清中的致炎因子影响来说，两种不同的训练方式起着完全相反的作用：有氧健身操能够降低致炎因子水平（IL-1β，IL-6，TNF-α），但是力量训练却使致炎因子的水平增加。结论：建议想增加肌肉量的年轻超重和肥胖男性在使用力量训练的同时，结合有氧健身操的锻炼方法，使身体逐渐恢复健康状态。  相似文献   

Comparison of visual,automatic and semiautomatic methods to determine ventilatory indices in 50 to 60 years old adults     

Martin Pühringer  Susanne Ring-Dimitriou  Thomas Stöggl  Bernhard Iglseder  Bernhard Paulweber 《Journal of sports sciences》2020,38(6):692-702

ABSTRACT

The aim of this study was to compare different methods of detecting ventilatory indices (VI) and to investigate the impact of cardiorespiratory fitness (CRF) level on VI detection. Fifty females and fifty males completed a graded exercise test until volitional exhaustion with continuous gas-exchange measurement. The first and second ventilatory indices (VI-1, VI-2) were detected through different single automatic methods and through a semiautomatic method which combines visual and automatic detection methods. Additionally, the VIs were detected visually by two experts which served as the study specific gold standard. When comparing the semiautomatic method at VI-1 (intraclass correlation coefficients (ICC) 0.88 [0.81, 0.92], Bland-Altman bias ± limits of agreement (LoA) 55 ± 334 ml O₂ · min^?1) and VI-2 (ICC 0.97 [0.96, 0.98], LoA 1 ± 268 ml O₂ · min^?1) to the visually detected VI, high levels of agreements and no significant differences were found. This was not the case for any of the other automatic methods. Additionally, we couldn’t find any relevant differences regarding the CRF level.

We therefore concluded that the semiautomatic detection method should be used for VI detection, as results are more accurate than in any of the single-automatic methods.

Abbreviations: CPET: cardiopulmonary exercise test; CRF: Cardiorespiratory fitness; VO_2peak: peak oxygen uptake; VI-1: first ventilatory indices; VI-2: second ventilatory indices; LoA: Bland-Altman bias ± limits of agreement; ICC: intraclass correlation coefficient.  相似文献   

Fitness,physical activity and academic achievement in overweight/obese children     

Cristina Cadenas-Sanchez  Jairo H. Migueles  Irene Esteban-Cornejo  Jose Mora-Gonzalez  Pontus Henriksson  María Rodriguez-Ayllon 《Journal of sports sciences》2020,38(7):731-740

ABSTRACT

The aim of this study was to examine the associations of fitness and physical activity with academic achievement in children with overweight/obesity. A total of 106 (10.0 ± 1.1y, 61 boys) children participated. The fitness components were assessed by field and laboratory-based tests. Physical activity was measured via accelerometry. The academic achievement was assessed by a standardised test and school-grades. Field-based cardiorespiratory fitness was associated with language skills (ß-standardised- ranging from 0.281 to 0.365, p < 0.01). The field-based muscular strength was associated with grade point average, natural and social sciences, and foreign language (ß = 0.280–0.326, all p ≤ 0.01). Speed-agility was associated with some language-related skills (ß = 0.325–0.393, all p ≤ 0.01). The laboratory-based muscular strength also showed an association with mathematics skills (ß = 0.251–0.306, all p ≤ 0.01). Physical activity did not show significant association with academic achievement (p > 0.01). Overall, the significant associations observed for muscular strength and speed/agility were attenuated and disappeared in many cases after additional adjustments for body mass index and cardiorespiratory fitness, indicating that these associations are inter-dependent. Our study contributes by indicating that other fitness components apart from cardiorespiratory fitness, such as muscular strength and speed-agility, are positively associated with academic achievement. However, these associations appear to be dependent on body mass index and cardiorespiratory fitness.  相似文献   

Cardiorespiratory fitness and telomere length: a systematic review     

Adilson Marques  Élvio Rubio Gouveira  Miguel Peralta  João Martins  Joed Venturini  Duarte Henriques-Neto 《Journal of sports sciences》2020,38(14):1690-1697

ABSTRACT

This study aimed to systematically review the association between cardiorespiratory fitness and telomere length (TL). Studies were identified from searches in Cochrane Central, PubMed, Scopus, Sportdiscus, and Web of Science databases through July 2019. Eligibility criteria included: cross-sectional, prospective, and experimental study design; outcomes included TL; results expressed the relationship between cardiorespiratory fitness and TL; studies published in English, Portuguese, or Spanish. A total of 20 articles met the inclusion criteria. Sixteen studies (80%) reported a significant relationship between cardiorespiratory fitness, or training load, and TL. Better cardiorespiratory fitness or a large cardiorespiratory training load are associated with an increase in TL. Although, TL was related to regular moderate-to-vigorous aerobic exercise and cardiorespiratory fitness in older healthy humans, it was not related to cardiorespiratory fitness among young subjects. There seems to be a positive and significant relationship between cardiorespiratory fitness and TL, mainly among middle age and older people, which emphasizes the importance of cardiorespiratory fitness for healthy ageing. Therefore, endurance exercise and better cardiorespiratory fitness may regulate the TL in middle age and older adults, slowing the cellular ageing process.  相似文献   

对间歇性低氧训练提高机体有氧代谢能力的机制分析     

李登光  景会锋 《四川体育科学》2005,(4):23-26

本文运用文献综述和逻辑分析的方法，通过对间歇性低氧训练相关研究的分析和综述，发现：间歇性低氧训练是提高机体有氧代谢能力的1种手段。因此，从与机体有氧代谢相关的呼吸系统、心血管系统、血液系统、组织细胞和骨骼肌等几个方面对其机制进行分析，为机体有氧代谢的相关研究提供一定的理论参考。  相似文献