Validity and reliability of a linear positional transducer across commonly practised resistance training exercises

This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three-dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R² values of >0.85 for all variables excluding deadlift mean velocity (R² = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance.     

Kinematic analysis of the drag flick in field hockey

Attaining high speed of the stick head and consequently of the ball is essential for successful performance of the drag flick in field hockey, but the coordination pattern used to maximise stick head speed is unknown. The kinematics of the drag flick was studied in ten elite hockey players who performed twenty shots each towards a target located 1.5 m high. A 150 Hz active marker motion analysis system was used, alongside two force plates to detect foot touchdown. Angular velocity and contribution to stick endpoint speed of upper body joints were analysed. Repeated measures ANOVA was used to compare timing of onset and peak angular velocities between joints. Participants used a kinematic pattern that was close to a proximal-to-distal sequence. Trunk axial rotation and lateral rotation towards the target, right wrist flexion and left wrist extension were the main contributors to stick endpoint speed. Coaches should emphasise trunk rotations and wrist flexion and extension movements for maximising stick head speed. Given the high level of the participants in this study, the coordination of joints motions, as reported here, can serve as a guideline for drag flick training.     

Estimating fat-free mass in elite-level male rowers: a four-compartment model validation of laboratory and field methods

The purpose of this study was to investigate the accuracy of fat-free mass (FFM) estimates from two-compartment (2C) models including air displacement plethysmography (ADP), ultrasound (US), near-infrared interactance (NIR), and the Jackson and Pollock skinfold equation (SKF) against a criterion four-compartment (4C) model in elite male rowers. METHODS: Twenty-three elite-level male rowers (mean± SD; age 24.6 ± 2.2 years; stature: 191.4 ± 7.2 cm; mass: 87.2 ± 11.2 kg) participated in this investigation. All body composition assessments were performed on the same day in random order, except for hydrostatic weighing (HW), which was measured last. FFM was evaluated using a 4C model, which included total body water from bioimpedance spectroscopy, body volume from HW, and total body bone mineral via dual-energy X-ray absorptiometry. The major findings of the study were that the 2C models evaluated overestimated FFM and should be considered with caution for the assessment of FFM in elite male rowers. Future studies should use multiple-compartment models, with measurement of TBW and bone mineral content, for the estimation of FFM.     

以“颗粒物(PM10、PM2.5)污染”看户外体育锻炼人群对空气质量的感知

户外体育锻炼是体育锻炼和保持、提高健康状态的一种重要锻炼方式。在污染的空气中锻炼不仅会对锻炼效果产生不良影响,还会削弱体育锻炼人群对体育锻炼的积极性。江苏省空气质量日优秀率偏低,首要污染物主要为颗粒物(PM10、PM 2.5)。江苏省户外体育锻炼人群在锻炼环境、空气质量状况获取途径、对其危害性的认识、其与锻炼时间段的关系等方面存在着认识不足的问题。     

优秀运动员竞技心理障碍分析及对策探讨

采取文献检索和调查访谈等方法分析了优秀运动员竞技心理素质的重要性、竞技心理障碍的表现及成因,探讨了排除竞技心理障碍的对策。     

超强度想象理论在竞技体育运动中的作用及应用

竞技运动员在比赛之前,往往会出现赛前紧张状态、赛前淡漠状态以及赛前盲目自信状态。通过对超强度想象理论的提出和研究,试图通过超强度想象消除竞技运动员的不良赛前状态,以至于达到最佳战斗准备状态。     

大气污染对悬铃木叶片几种生理生化指标的影响

大气污染会影响悬铃木叶片的电导率、游离Pro和可溶性糖含量以及抗氧化能力 ,致使叶片电导率升高 ,游离Pro和可溶性糖含量增加 ,抗氧化能力增强。交通污染对植物影响的性质与程度与工业污染相当 ,应引起重视。绿化可减轻空气污染 ,提高环境质量     

关于图书馆建筑节能的研究与实践

节能是现代社会对图书馆建筑的要求，也是图书馆自身生存和发展的必然要求。空调系统、照明系统、窗墙比等是图书馆建筑节能设计的关键；设计师、业主对建筑节能的认知和重视程度也是重要影响因素。     

足球运动员高原训练科学化探索

高原训练作为适应高原比赛和提高平原比赛体能的一种训练方法已逐步地融人足球的科学化训练实践之中,但尚未成熟理论和实践体系.笔者通过对高原训练基本原理的研究,并结合多年足球训练的实践经验,探讨高原训练对足球运动员的影响及足球运动员高原训练的科学化安排,以期为我国足球运动员高原训练实践提供理论依据.     

室内空气污染对运动时人体机能的影响

对室内主要空气污染物的特性、作用机理,及其对人体身体健康,运动时人体身体机能的影响进行综合分析,探讨室内主要空气污染物影响运动时人体身体机能的作用机制,为实验研究提供理论依据。