Long-term Tai Chi exercise increases body stability of the elderly during stair ascent under high and low illumination*

The effects of long-term Tai Chi exercise on body stability of the elderly during stair ascent under high and low illumination were investigated. Forty-five healthy elderly women were divided into three groups, namely, Tai Chi exercise group, brisk walking group and no-exercise control group. All the participants ascended a staircase, during which force platforms and a motion capture system collected the data. Under the high illumination, Tai Chi exercise participants exhibited higher loading rate and anteroposterior centre of pressure (COP_ap) displacement as well as a lower braking impulse than no-exercise group. Under the low illumination, Tai Chi exercise participants demonstrated higher COP_ap and mediolateral centre of pressure (COP_ml) displacements as well as lower braking and lateral impulses compared with no-exercise participants. The centre of mass (COM)_ml sway in Tai Chi and no exercise participants were higher, the loading rates in Tai Chi and walking participants were higher, and the lateral impulse in no exercise participants was higher under low illumination than under high illumination. Thus, low illumination increases the risk of falling. Tai Chi participants increased their foot clearance, head inclination angle and COP_ap displacement under low illumination to increase their stability during stair ascent.     

Estimation of Errors in Force Platform Data

Abstract

Young, healthy varsity swimmers were studied over a period of 14 months with regard to the effect of a typical training and competitive collegiate swimming program on plasma cholesterol and phospholipids. Chemical analyses on blood cholesterol and phospholipids were made and compared for competitive and noncompetitive seasons. A dietary analysis was also made during the competitive season. In both the original and subsequent study involving the current (1960–61) varsity swimmers analyses were made of the acute effect of physical exertion on plasma cholesterol and phospholipids.

The exercise, used for conditioning varsity swimming athletes did not significantly lower blood cholesterol and phospholipids. However, this result is not necessarily at variance with the view of some investigators that exercise does exert a hypocholesterilizing effect. Several factors are discussed which are thought to have influenced ultimate results.     

Test–retest reliability of the Tekscan® F-Scan® 7 in-shoe plantar pressure system during treadmill walking in healthy recreationally active individuals

In-shoe plantar pressure systems are commonly used in clinical and research settings to assess foot function during functional tasks. Recently, Tekscan® has updated their F-Scan® in-shoe plantar pressure system; however, this system’s test–retest reliability has not been established. Therefore, the purpose of this study was to determine the test–retest reliability of the F-Scan® 7 system in recreationally active individuals during treadmill walking. Seventeen healthy adults completed 2 sessions of treadmill walking. For each session, participants were fitted for shoes and pressure insoles and walked on a treadmill at a self-selected pace for 30 s. Following the sessions, the test–retest reliability peak pressure, pressure time integral, average pressure and pressure contact area over 4 regions of the foot (heel, mid-foot, forefoot and toes) was assessed by calculating intraclass coefficients (ICC 2,k) and coefficient of variation percentage (CoV%). Pressure contact area consistently had the highest ICCs and lowest CoV% (ICCs: 0.91–0.98; CoV%: 2.7–7.8%). Whereas, the forefoot and toe regions had the highest ICCs for all 4 measures (ICCs: 0.83–0.98; CoV%: 3.1–13.4%). During treadmill walking in healthy recreationally active individuals, the reliability of the new Tekscan F-Scan® ranged from poor to high and was dependent on the measure and region of the foot.     

Stress and performance: An application of Gray's three‐factor arousal theory to basketball free‐throw shooting

The suitability of Gray's (1975) three‐factor arousal theory as a model of human performance under stress was investigated in a study of basketball free‐throw shooting. Free‐throw attempts, made by members of an NCAA Division I men's varsity team, were videotaped during one full season. On the basis of Gray's theory, we predicted that increased stress (assumed to be present in games as opposed to practices) would be associated with longer pre‐shot preparations and a greater incidence of overthrow shots. The prediction was confirmed by the results. Moreover, we found that free‐throws were more frequently overthrown when attempted during crucial rather than non‐crucial game situations. Further tests of the utility of Gray's theory are suggested.     

Relative age effect and performance in the U16, U18 and U20 European Basketball Championships

This study sought to determine the association of relative age and performance of young elite basketball players. The distribution of the birth dates, heights, positions, classification and performance of the male and female participants (n = 2395) of the U16, U18 and U20 European Basketball Championships were analysed. We found an over-representation of players born during the initial months of the year in all groups, with the relative age effect being more evident in players of the U16 and U18 groups, than of the U20 teams, particularly in male squads. Nevertheless, in the U20 championships, those teams that had the oldest players performed the best. In all championships, the oldest participants played more minutes. In addition, relatively older male players scored better in total points and in performance index rating when results were normalised to played time. This effect was not found for female players. Regarding playing position, different distributions of birth dates were observed due to each position’s physical requirements. Thus, basketball coaches and managers should keep these results in mind when they select players because if not, they might subject players who are born towards the end of the year to a negative selection bias.     

少年男子篮球运动员一年训练前后身体机能变化的研究

研究少年男子篮球运动员一年训练前后握力、无氧功率、最大摄氧量、血红蛋白、血清睾酮、免疫球蛋白等机能指标的变化。实验结果表明 :1.经过一年训练 ,少年男子篮球运动员的身高 ,体重 ,握力均有显著增长 ,说明训练符合生长规律。 2 通过 1年训练 ,少年男子篮球运动员在运动负荷后 2、5、10min血乳酸水平下降、清除加快 ,最大摄氧量显著提高 ,表明采用的训练方法对运动员有氧代谢能力的提高有帮助。 3 在训练后 ,出现免疫球蛋白下降的现象 ,是今后应加以注意的问题     

普通高校篮球队队员人际关系和谐性与场上表现的研究

对粤东高校男子篮球队86名队员人际关系和谐性、场上表现、投篮命中率进行统计分析。结果表明：队员的投篮命中率与其人际关系和谐性明显相关，投篮命中率越高，人际关系和谐性分值越低，和谐性越高。队员在场上的各种表现与人际关系和谐性存在一定的关联性，提示队员的人际关系和谐性对其在比赛中的发挥有一定的影响。粤东高校男子篮球队中，多数队员人际关系和谐性较好，但也有少部分的人际关系存在不同程度的困扰，且代表队水平越高，出现人际关系困扰队员的比例越高。     

Performance analysis of elite men’s and women’s wheelchair basketball teams

Abstract

The purpose of the present study was to identify which game-related statistics discriminate winning and losing teams in men’s and women’s elite wheelchair basketball. The sample comprised all the games played during the Beijing Paralympics 2008 and the World Wheelchair Basketball Championship 2010. The game-related statistics from the official box scores were gathered and data were analysed in 2 groups: balanced games (final score differences ≤12 points) and unbalanced games (final score differences >13 points). Discriminant analysis allowed identifying the successful 2-point field-goals and free-throws, the unsuccessful 3-point field-goals and free-throws, the assists and fouls received as discriminant statistics between winning and losing teams in men’s balanced games. In women’s games, the teams were discriminated only by the successful 2-point field-goals. Linear regression analysis showed that the quality of opposition had great effects in final point differential. The field-goals percentage and free-throws rate were the most important factors in men’s games, and field-goals percentage and offensive rebounding percentage in women’s games. The identified trends allow improving game understanding and helping wheelchair basketball coaches to plan accurate practice sessions and, ultimately, deciding better in competition.     

青少年男子铅球运动员施力特征探析

采用三维数字测力铅球仪对青少年运动员在整个投掷过程中的施力特征与动作技术特征进行分析,结果表明:(1)在完整推铅球动作过程中运动员对铅球的作用力曲线与铅球速度变化趋势基本一致,在最后用力动作过程中,合力曲线呈“双峰型”;(2)在最后用力开始左脚着地瞬间力值逐渐增大,到右腿蹬转使运动员身体由侧对投掷方向转为正对投掷方向瞬间出现第一次峰值;在推掷臂肘关节夹角约为90°时出现第二次峰值。     

基于核心力量与爆发力训练的篮球青少年力量训练方法研究

运用文献资料法、专家访谈法研究核心力量与爆发力训练对青少年篮球运动员的影响。针对青少年篮球运动员的力量训练水平不足的问题,从青少年力量训练方法的文献调研入手,结合竞技篮球运动的项目特点以及青少年力量训练的基本规律,探索合理化、科学化的青少年篮球运动员力量训练方法。     

Basketball shooting strategies — the free throw,direct shot and layup

A rationale and geometric parameters for optimal basketball shooting are provided. The premise is that shots requiring the least energy are the easiest to control and thus have the greatest probability of success. The kinematics of the ball movement are modelled and simulated for the free throw, for the direct shot, and for the bank shot off the backboard (the ‘layup’). For the layup, the analysis includes the effects of friction, ball inertia, ball spin and impact restitution. The results provide a means for shot planning and for coaching to improve shooting technique. The advantage of the layup for close-in shooting is demonstrated. Results of numerical parameter studies are also presented, demonstrating the ranges of allowable shooting error for the various shots, and thus also identifying the shots with highest probability of success.     

从中美篮球校园文化差异看高校篮球文化建设

针对中美篮球校园文化的对比,尤其是我国高校篮球发展的现状进行了分析,指出篮球不应仅仅作为一种大学生娱乐健身的方式,而应该充分理解篮球的精神和人文情怀,在篮球运动中健全自己的心智和适应能力,并提出高校竞技篮球应作为大学生球员接受教育的一种途径,充分融入到校园生活中,建立健全的校园篮球文化.     

部分优秀女子篮球运动员竞技能力的主导因素分析

在查阅有关文献的基础上,运用逐步回归的方法,分析研究了组成我国部分优秀女子篮球运动员竞技能力的主导因素,并建立了回归模型,为优秀女子篮球运动员的后期选材和训练提供了一定的参考依据。