Scapulohumeral kinematic assessment of the forward kayak stroke in experienced whitewater kayakers

By understanding the normal humeral and scapular kinematics during the kayak stroke, inferences about the relationship of kayaking technique and shoulder injury may be established. The purpose of this study was to describe scapular and humeral kinematics and to compare dominant versus nondominant symmetry in healthy whitewater kayakers performing the forward stroke. Twenty-five competent whitewater kayakers (mean age: 34.1 +/- 9.4 years, mean height: 1.768 +/- 0.093m, mean mass: 78.2 +/- 13.0 kg) underwent humeral and scapular kinematic assessment, using an electromagnetic tracking device, while kayaking on a kayak ergometer. Paired t-tests were used to determine symmetry. Scapular and humeral kinematic means and standard deviations at six time points during the kayak stroke were described. Scapular and humeral kinematics were shown to be similar upon bilateral comparison. The greatest potential for injury during the forward stroke may be at thrust paddle shaft vertical when the humerus is maximally elevated in internal rotation and adduction as subacromial structures may be mechanically impinged. The relationship between scapulohumeral kinematics related to injury at other time points are also described.     

Characterizing the mechanical parameters of forward and backward falls as experienced in snowboarding

Wrist injuries are frequently observed after falls in snowboarding. In this study, laboratory experiments mimicking forward and backward falls were analysed. In six different falling scenarios, participants self-initiated falls from a static initial position. Eighteen volunteers conducted a total of 741 trials. Measurements were taken for basic parameters describing the kinematics as well as the biomechanical loading during impact, such as impact force, impact acceleration, and velocity. The effective mass affecting the wrist in a fall also was determined. The elbow angle at impact showed a more extended arm in backward falls compared to forward falls, whereas the wrist angle at impact remained similar in forward and backward falls. The study results suggest a new performance standard for wrist guards, indicating the following parameters to characterize an impact: an effective mass acting on one wrist of 3–5 kg, an impact angle of 75° of the forearm relative to the ground, and an impact velocity of 3 m/s.     

Prevalence of shoulder pain in Swedish flatwater kayakers and its relation to range of motion and scapula stability of the shoulder joint

Few studies have investigated the incidence of injuries in kayakers. The aim was to study the prevalence of shoulder pain in competitive flatwater kayakers and to evaluate any differences in range of motion or scapula stability of the shoulder joint among kayakers with or without the history of shoulder pain. Thirty-one kayakers were participated in the study, and a questionnaire including background data was used. Shoulder range of motion was measured with a goniometer, and the participants were observed for scapula dyskinesis in flexion and abduction. Of the participating kayakers, 54.8% (n = 17) had experienced shoulder pain. Kayakers who had experienced shoulder pain showed a significantly lower degree of internal rotational range of motion versus kayakers with no reported shoulder pain, with a mean degree of internal rotation in the right shoulder 49.3 vs 60.0 (P = 0.017) and the left shoulder 51.9 vs 66.0 (P = 0.000). Kayakers who had experienced shoulder pain were also observed with a scapular dyskinesis (n = 15 of 17 kayakers) to a significantly higher degree (P = 0.001) than kayakers with no reported shoulder pain. Findings suggest that screening for scapular dyskinesis and testing for rotational range of motion in the shoulder joint is essential in order to treat and maybe prevent shoulder pain in kayakers.     

国内男子优秀皮艇运动员途中划划桨技术与效果的研究——兼谈双机同步二维摄像法和皮艇专项分析系统

采用双机同步二维摄像法对参加2005年全运会预选赛的12名男子优秀运动员在500m单人艇比赛时的途中划过程进行了现场拍摄，并且运用自行研发并与摄像方法相适应的皮艇运动专项解析软件对所拍的图像资料进行解析。运用理论和统计学方法分析了途中划的划桨技术，拟揭示国内单人皮艇500m优秀运动员途中划的技术动作的运动学特征，以期从理论和解析数据两方面探究提高途中划划桨效果的皮艇技术的改进方向。结论：双机同步二维摄像方法和专项分析系统使用效果良好；根据拉桨过程中桨获得推进力的主要来源，整个拉桨阶段可分为入水升力推进时相、阻力推进时相和出水升力推进时相；拉桨时艇速的变化特征是分析划桨效果的重要依据之一；随速度的提高，后拉划距减小；最大艇速出现时刻前移和速度下降率增大，阻力作用于艇和桨的相对时间延长；在出水升力推进时相，减小划桨的水平速度，加大垂直速度，加大出水角，将更有利于提高艇速和划桨效果。     

Kinetic and kinematic analysis of stamping impacts during simulated rucking in rugby union

Laceration injuries account for up to 23% of injuries in rugby union. They are frequently caused by studded footwear as a result of a player stamping onto another player during the ruck. Little is known about the kinetics and kinematics of rugby stamping impacts; current test methods assessing laceration injury risk of stud designs therefore lack informed test parameters. In this study, twelve participants stamped on an anthropomorphic test device in a one-on-one simulated ruck setting. Velocity and inclination angle of the foot prior to impact was determined from high-speed video footage. Total stamping force and individual stud force were measured using pressure sensors. Mean foot inbound velocity was 4.3 m ? s^?1 (range 2.1–6.3 m ? s^?1). Mean peak total force was 1246 N and mean peak stud force was 214 N. The total mean effective mass during stamping was 6.6 kg (range: 1.6–13.5 kg) and stud effective mass was 1.2 kg (range: 0.5–2.9 kg). These results provide representative test parameters for mechanical test devices designed to assess laceration injury risk of studded footwear for rugby union.     

Synchronized metronome training induces changes in the kinematic properties of the golf swing

The purpose of this study was to evaluate possible effects of synchronized metronome training (SMT) on movement dynamics during golf-swing performance, as captured by kinematic analysis. A one-group, between-test design was applied on 13 male golfers (27.5 ± 4.6 years old, 12.7 ± 4.9 handicap) who completed 12 sessions of SMT over a four-week period. Pre- and post-assessments of golf swings with three different clubs (4-iron, 7-iron, and pitching wedge) were performed using a three-dimensional motion capture system. Club velocity at three different swing phases (backswing, downswing, and follow-through) was measured and cross-correlation analysis of time-series signals were made on joint couplings (wrist–elbow–shoulder) of both arms, and between joints and the club, during the full golf swing. There were significantly higher cross-correlations between joint-couplings and concomitant changes of the associated phase-shift differences, as well as reduced phase-shift variability at post-test. No significant effect of SMT was found for the club velocities. We suggest that domain-general influences of SMT on the underlying brain-based motor control strategies lead to a more coordinated movement pattern of the golf-swing performance, which may explain previous observations of significantly improved golf-shot accuracy and decreased variability after SMT.     

篮球运动中的常见损伤分析

篮球运动产生的初期,是没有任何身体接触的,而且也是禁止身体接触的。但随着篮球运动的发展,观众要求的提高,比赛竞争性、对抗性的日益激烈,篮球比赛规则从身体不接触过渡到身体可以接触,进而成为了身体直接对抗。随之而来的就是比赛和训练中出现的各种运动损伤也不断增多。文章通过对日常和比赛中产生运动损伤进行分析,以加强防范措施,最大限度地减少或避免损伤,从而保证篮球的训练与教学的正常进行。     

轮滑项目运动损伤的调查与分析

轮滑运动是一项受到广大青少年喜爱的运动,在社会和普通高校中得到普遍开展,但轮滑活动的过程中运动损伤发生的几率相对较高,严重影响轮滑运动的开展。采用文献资料法和问卷调查等方法,分析轮滑活动中运动损伤产生的原因和损伤部位,为高校轮滑运动的教学、训练、课外活动以及全民健身活动提供指导。     

哈尔滨市高校大学生冰上课运动损伤调查分析

通过文献资料法、问卷调查法和逻辑分析法对哈尔滨市高校大学生冰上课损伤情况进行调查分析,损伤发生的主要原因有场地、器材因素,准备活动不合理因素,天气因素等七个主要因素。提出预防冰上课中产生运动损伤的主要方法。从而减少冰上课中运动损伤的发生,促进冰上运动在哈尔滨高校更好、更健康的发展。     

高校高山滑雪教学课中运动损伤调查与分析

通过文献资料法、问卷调查法和逻辑分析法对高校高山滑雪教学课的运动损伤进行调查分析。结果显示:高山滑雪教学课学生的运动损伤具有男性高于女性、下肢发病率较高等特点。针对其特点提出加强心理素质训练、重视准备活动、加强安全意识教育、提高教学科学化水平等措施,为减少和避免运动损伤的发生和圆满地完成教学任务提供参考。