Body Composition and Anthropometric Correlates of Isokinetic Leg Extension Strength of Young Adult Males

Abstract

The present study examined the relative importance of body size and composition as determinants of individual differences in isokinetic leg extensor strength in young adult males performing at slow, moderate, and fast speeds. The subjects were 31 males between the ages of 19 and 29 years, who were not participating in weight training programs. Low to moderate correlations were found between isokinetic strength and body size or body composition measurements. At each speed, similar proportions of the variance in peak torque values were accounted for by lean body weight (23-30%) and thigh volume (20-37%). However, body weight, often suggested as the best reference standard for equalizing strength scores, also accounted for only 13-24% of the variance in peak torque values at each of the speeds tested. The moderate correlations reported in this study do not support the use of body size and composition measurements as a means of adjusting strength values.     

智障学生全脑型体育教育模式的理论与实践研究

运用实验、文献资料研究、个案观察与分析、数理统计等方法,对上海市4所辅读学校共计138名智障学生进行全脑型体育教育模式的实验研究。结果表明,强化智障学生不同肢体的体育训练或体育活动,是神经系统交互控制功能运作过程中产生左、右脑功能协同发展后迁移效果的外在反映,对于智障学生运动技能及身体素质的提高、肢体运动能力缺陷的补偿以及不良行为的矫正有显著作用。     

Body Mass and Circumference of Upper Arm Are Associated With Race Performance in Ultraendurance Runners in a Multistage Race—The Isarrun 2006

In the present study, we investigated the association of anthropometric parameters with race performance in ultraendurance runners in a multistage ultraendurance run, in which athletes had to run 338 km within 5 consecutive days. In 17 male successful finishers, calculations of body mass, body height, skinfold thicknesses, extremity circumference, skeletal muscle mass (SM), and percentage body fat (%BF) were performed before the race to correlate anthropometric parameters with race performance. A positive association was shown between total running time and both body mass (r² = .29, p < .05) and upper arm circumference (r² = .23, p < .05). In contrast, body height, skinfold thicknesses, extremity circumference, SM, and %BF showed no association with race performance (p > .05). We concluded that in a multistage ultraendurance run, body mass and upper arm circumference were negatively associated with race performance in well experienced ultraendurance runners. In contrast, body height, skinfold thicknesses, circumferences of the other extremities, SM, and %BF showed no association with race performance.     

Intraseason changes in the body composition of collegiate female gymnasts

Body composition measures were collected pre‐, mid‐ and post‐season on a team of eight national‐calibre collegiate women gymnasts to examine intraseason changes. Also analysed were interseason changes using pre‐ and post‐season data on five of the eight subjects during the current and previous year, according to a 2 x 2 (years x tests) analysis of variance repeated‐measures design. Skinfold, circumference and diameter measures were collected with percentage body fat, lean body mass and body density determined by regression equations developed specifically for collegiate female gymnasts.

Intraseason body weight decreased significantly from pre‐ to mid‐season (x = 55.0 and 53.6 kg respectively); but the difference between mid‐ and post‐season (53.9 kg) values was not significant (P>0.05). The majority of the 1.4 kg weight loss occurred during intense pre‐season conditioning and not during the actual season. Percentage body fat, on the other hand, decreased significantly from pre‐to mid‐season and mid‐ to post‐season (x = 21.4%, 17.4% and 13.45% respectively; P<0.0005). Body density increased significantly from pre‐ to mid‐season and mid‐ to post‐season (x = 1.0476, 1.0584 and 1.0681 respectively; P<0.0005). Of the circumference and skinfold values used in calculating percentage body fat and body density, only the skinfold values displayed significant decreases throughout the season.

Interseason analyses revealed no significant changes in any of the dependent measures between seasons, despite consistent trends. There were no significant years x tests interactions and all intraseason changes for two seasons (n = 5) were the same as those found in more detailed analysis of a single season (n = 8) except in the case of weight loss, which was marginally significant (P < 0.046) in the single‐season and not in the dual‐season analysis (P>0.05).

Body composition of these gymnasts changed in many ways within competitive seasons. The most pronounced changes observed were decreases in subcutaneous fat and increases in body density. This study reinforces the need for administrators, coaches and athletes to be concerned with percentage body fat and skinfold measures rather than weight alone when determining if a person is ‘fat’.     

2012赛季中国足球超级联赛球队成绩与技术统计的多元分析

针对足球运动项目的特点,通过运用因子分析法提取原参数指标的共性因子,建立影响球队成绩的共性因子得分标准化变量线性组合式。根据因子得分排名,对其差异性进行分析,探索各球队本赛季的成绩能否代表其真实实力,为球队实力排名建立新的评价体系,对球队赛前科学有效的训练控制,提高球队比赛成绩提供科学的理论依据。     

Motor Proficiency Traits of Deaf Children

Abstract

This study examined the physical, psychological and perceptual/visual variables related to elite archers' shooting performance. Complete data on 62 variables were obtained on male (n = 44) and female (n = 35) archers, who were tested during the years 1982-1984. In order to reduce the number of variables, only those that correlated significantly with performance (r > .25, p < .005) were retained. This yielded seven variables. These variables were then combined into an overall hierarchical regression model. The overall model was significant (p <.001, adjusted R² = .53). This analysis indicated that relative leg strength, reaction time, depth perception, endomorphy, imagery usage, confidence, and focus on past mistakes were variables associated with archery performance. Finally, the total sample was classified into two groups on the basis of the shooting scores. Discriminant function analysis indicated that 81% of the archers were classified correctly on the basis of these significant predictors.     

Bioimpedance patterns and bioelectrical impedance vector analysis (BIVA) of road cyclists

Bioelectrical impedance vector-analysis (BIVA) describes cell-mass, cell function and hydration status of an individual or a group. The goal of the present investigation was to provide bioelectrical impedance data for 525 male road cyclists (155 professionals, 79 elite, 59 elite-youth, and 232 amateurs) at the time of their optimal performance level. Data were plotted on the resistance-reactance (R-Xc) graph to characterize cyclists group vectors using BIVA. Compared to the general male population, the mean vector position of the road cyclists indicates a higher body cell mass (BCM) and phase angle (p<0.001). The vector position of the high-performance, compared to the amateur cyclists showed similar patterns with higher BCM and phase angles and higher reactance values for the high-performance athletes (p<0.001). The bio-impedance data were used to calculate the 50%, 75%, and 95% tolerance ellipses of each group of cyclists. The characteristic vector positions of the road cyclists indicate normal hydration and greater muscle mass and function of the high-performance cyclists compared to amateur cyclists and the normal population. The cyclists specific tolerance ellipses, particularly the high-performance cyclists might be used for classifying a cyclist according to the individual vector position and to define target vector regions for lower level cyclists.     

Physiological and Anatomical Characteristics Of Outstanding Female Junior Tennis Players

Purpose: The purpose of this study was to investigate the physiological adaptations of resistance training (RT) in prepubertal boys. Methods: Eighteen healthy boys were divided into RT (n = 9, M_age = 10.4 ± 0.5 years) and control (CTR; n = 9, M_age = 10.9 ± 0.7 years) groups. The RT group underwent a resistance training during 12 weeks, 3 times per week, performing 3 sets of 6 to 15 repetitions at intensities ranging from 60% to 80% of maximal dynamic strength (1-repetition maximum [1-RM] values). Before and after the training, the groups were assessed in their body mass and composition (dual-energy X-ray absorptiometry), isokinetic dynamometry, 1-RM, and ergoespirometry. Moreover, force per unit of muscle volume was calculated by the quotient between 1-RM and lean mass. Results: Both groups presented statistically significant (p < .05) increases in the 1-RM and force per unit of muscle volume in the knee extension and elbow flexion, but these strength increases were statistically significantly greater in the RT group (effect size [ES] = 2.83–9.00) than in the CTR group (ES = 0.72–1.00). Moreover, both groups statistically significantly increased in lean body mass variables (ES = 0.12–0.38). However, increases in the fat mass variables occurred only in the CTR group (ES = ? 0.01–0.50), whereas no changes were observed in the RT group. Furthermore, there were statistically significant increases in all bone mineral content variables (ES = 0.13–0.43), without differences between groups. No cardiorespiratory changes were observed. Conclusion: Twelve weeks of RT was effective in improving strength and force per unit of muscle volume and prevented fat mass increases in boys.     

力量训练、有氧运动对体能类男性运动员BMI、骨骼肌含量、体脂百分比的影响

选取20名体能类男性运动员,分为力量训练组和有氧训练组进行为期8周的对照实验。实验发现不同运动对人体成分的改变效果不同,力量训练可以促进骨骼肌的增长,有氧训练可以起到降低体重、减小体脂、抑制骨骼肌增长的作用。     

Age and Sex Differences in Motor Performance of 3 through 6 Year Old Children

Abstract

This study examined the relationship of age and sex to the performance of 3, 4, 5, and 6 year olds on seven motor performance test items. Although significant age and sex differences were found on most of the motor tests, it appears that age generally was related more to performance than was gender. Overall, change with age was fairly linear except perhaps for balancing and a general tapering in improvement in the 5 to 6 year old category. On the tests of throwing and balancing, gender was as important as age, or more so, in its relationship to performance. Boys were superior to girls at all ages on the throwing tests; girls were superior to boys at age 6 on the Balance test. Gender differences of a lesser magnitude were found on the Speed Run and Standing Long Jump tests with the performance of boys generally being superior to the performance of girls. Thus, it appears that gender differences in motor performance occur as early as the preschool years. Interestingly, except for the Balance test, on all the tests the 3 and 4 year old boys performed similarly and the 5 and 6 year old boys performed similarly. For the girls there were more significant differences from year to year in performance, with the data generally indicating at least three distinct skill groups for girls from age 3 to 6.     

The relative age effect in the German Football TID Programme: Biases in motor performance diagnostics and effects on single motor abilities and skills in groups of selected players

Abstract

This study examined the disturbing effects of relative age on the talent identification process in the talent development programme of the German Football Association. The bias in the selection rate was examined via the extent of relative age effects. The bias in motor performance diagnostics was analysed by comparing the motor performance of selected players with normal motor development. The mechanisms underlying the relative age biases in motor performance were examined by modelling the direct and indirect effects of relative age on single motor performance tests for sprint, running agility, dribbling and ball passing and control. Data from 10,130 selected football players from the U12 to U15 age groups were collected in autumn 2010. The birth distribution differed significantly from the reference population with approximately 61% of the players born in the first half of the year. The selection probability was approximately two times higher for players born in the first quarter of the year than for players born in the last quarter. Revised motor performance diagnostics showed better results on average for relatively younger players. Path analysis revealed significant direct and indirect relative age effects for physiologically demanding tests and almost no effects for technically demanding tests. Large sample sizes allowed high resolution in relative age with additional informational content and multivariate modelling of the complex relationships among relative age, physical development and motor performance. The results are discussed on how relative age affects the effectiveness and fairness of talent identification and development processes.     

Indicators of sailing performance in youth dinghy sailing

Abstract

This study aimed to determine indicators of sailing performance in 2 (age) groups of youth sailors by investigating the anthropometric, physical and motor coordination differences and factors discriminating between elite and non-elite male optimist sailors and young dynamic hikers. Anthropometric measurements from 23 optimist sailors (mean ± SD age = 12.3 ± 1.4 years) and 24 dynamic youth hikers (i.e. Laser 4.7, Laser radial and Europe sailors <18 years who have to sail the boat in a very dynamic manner, due to a high sailor to yacht weight ratio) (mean ± SD age = 16.5 ± 1.6 years) were conducted. They performed a physical fitness test battery (EUROFIT), motor coordination test battery (Körperkoordinationstest für Kinder) and the Bucket test. Both groups of sailors were divided into two subgroups (i.e. elites and non-elites) based on sailing expertise. The significant differences, taking biological maturation into account and factors discriminating between elite and non-elite optimist sailors and dynamic hikers were explored by means of multivariate analysis of covariance and discriminant analysis, respectively. The main results indicated that 100.0% of elite optimist sailors and 88.9% of elite dynamic hikers could be correctly classified by means of two motor coordination tests (i.e. side step and side jump) and Bucket test, respectively. As such, strength- and speed-oriented motor coordination and isometric knee-extension strength endurance can be identified as indicators of sailing performance in young optimist and dynamic youth sailors, respectively. Therefore, we emphasise the importance of motor coordination skill training in optimist sailors (<15 years) and maximum strength training later on (>15 years) in order to increase their isometric knee-extension strength endurance.     

Exercise training modifies walking kinematics and energy cost in obese adolescents: A pilot controlled trial

Abstract

The aim of this study was to investigate the effects of a weight loss intervention based on physical exercise on the relationship between energy cost and stride frequency during walking in obese teenagers. Participants aged 13–16 years old were assigned to a training (n?=?14) and control (n?=?10) groups. During eight weeks, the training group performed three 60-min weekly sessions of high-intensity intermittent activities coupled with aerobic training. Body composition, gait parameters and energy cost during 4-min walking bouts at participants’ most comfortable speed and preferred stride frequency (PSF), PSF-10%, PSF?+?10%, PSF-20% and PSF?+?20% were measured before and after intervention. The effects of training and stride frequencies on the energy cost of walking were analysed by an ANOVA with repeated measures. The main results showed that the exercise intervention induced a significant increase in walking speed (+23.2%), and significant decreases in body mass (?1.4%), body fat percentage (?2.1%) and energy cost of walking at various frequencies (decreases ranging from ?10.5% to ?20.4%, p?<?.05). In addition, significantly greater decreases were shown at high frequencies (p?<?.05). No significant differences were shown in the control group (p?>?.05). These results suggest that this type of training is beneficial to reduce walking energy cost of obese teenagers, in particular at high frequencies. This should improve their well-being during daily activities.     

运动锻炼影响体脂代谢的研究进展

体育锻炼是减少体脂含量和提高运动性能的一种有效方法。本文就运动锻炼影响体脂代谢的研究进展作一综述。     

女子重竞技运动员体脂率与BMI、标准体重指数的相关分析

研究目的:通过测定女子重竞技运动员的体脂率fat%、BMI和标准体重指数(实际体重/标准体重),并对三种测定结果进行相关分析,寻求反映女子重竞技运动员体成分的可靠指标。研究方法:对34名重竞技运动员分别测定其体脂率、BMI和标准体重指数,比较各指标的影响因素,并对测定进行评价。研究结果:①fat%、BMI和标准体重指数分别为(19.3±3.81)%,(23.3±3.0)%和(106.4±16.2)%;②体脂率与BMI、标准体重指数呈低度相关,相关系数分别为r=0.431,r=0.355,P<0.01。结论:三个指标中,皮褶厚度推算脂肪含量是比较客观反映女子重竞技运动员身体成分的方法。     

初中学生运动和智力潜能的开发

选择初中一年级学生为研究对象,将其分为强化左侧肢体体育训练为主的实验班和按常规以右侧肢体训练为主的对照班进行了为期近1年的实验。通过合理安排体育教学内容、方法和手段对儿童少年运动和智力潜能的开发和儿童健康成长的影响进行研究探讨。对实验前后各项运动处方指标,心、智能力及学习成绩的综合测试和统计结果发现：强化左侧肢体体育训练的实验班,在左、右和双侧肢体运动技能、智力、心理和学习成绩上,以及运动技能与智力和学习成绩的相关性上,均比以强化右侧肢体体育训练为主的对照班明显的要高。这表明均衡地发展双侧肢体运动技能,更快、更好地开发儿童少年运动和智力潜能,培养“全脑型”人,是当前中学体育教育改革的一项重要任务。