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991.
Williams G Irwin G Kerwin DG Newell KM 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(1):20-33
The purpose of this study is to provide evidence of technique changes during learning a sports-specific skill, the looped bar longswing (LLS). Thirteen male participants with no previous high bar experience took part in a training study. Kinematic data were collected using a CODA motion analysis system (200 Hz) during eight weekly testing sessions. Analyses focused on the amplitude of swing and the functional phase (FP) actions, defined by the rapid flexion to extension of the shoulders and extension to flexion of the hips as the performer passed through the lower vertical. Three groups were identified based on the number of sessions it took each participant to perform the LLS (G1: most successful, G2: intermediate, and G3: least successful). All participants were able to significantly increase swing amplitude over the training period (p < 0.05). For each participant the hip FP started significantly: later for G1, earlier for G2, and did not change for G3. Extension actions at the shoulders were dissimilar to those reported for elite gymnasts performing the longswing. The FP of the hips provides a mechanism to distinguish between the learners of different skill levels. The study has provided support for a single-subject design when investigating technique changes during learning. 相似文献
992.
Schmitt KU Wider D Michel FI Brügger O Gerber H Denoth J 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(1):57-72
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 degrees of the forearm relative to the ground, and an impact velocity of 3 m/s. 相似文献
993.
Michael J. Shoemaker Amy B. Curtis Eric Vangsnes Michael G. Dickinson 《Cardiopulmonary Physical Therapy Journal》2012,23(3):5-15
Purpose
The purpose of the present review was to use existing, published data to provide an estimate of the amount of change in six-minute walk test distance (Δ6MWT) that represents a clinically meaningful change in individuals with chronic heart failure (CHF).Methods
The present review included two separate literature searches of the CINAHL and Medline databases for articles that: (1) reported the intraclass correlation coefficient (ICC) of the 6MWT in individuals with CHF, and (2) used the 6MWT along with either aerobic capacity or health-related quality of life (HRQL) as study endpoints in randomized controlled trials (RCTs) of exercise-based intervention for individuals with CHF. The ICCs were used to calculate the minimum detectable difference (MDD) at the 95% confidence interval for each included study. The Δ6MWT associated with aerobic capacity and HRQL within-group effect sizes for the intervention and control groups in each included RCT was analyzed using receiver operating characteristic (ROC) curves.Results
Thirteen articles reported the ICC for the 6MWT. The mean (standard deviation) MDD calculated based on these data was 43.1(16.8) m. Eighteen RCTs measured the 6MWT and either aerobic capacity and/or HRQL. A Δ6MWT of 40–45 m was associated with at least moderate aerobic capacity and HRQL effect sizes in the intervention groups. The Δ6MWT thresholds that discriminated between intervention and control groups using ROC curves revealed the following sensitivity/specificity for the respective thresholds: 19 m, 94.4/83.3%, 32 m, 83.3/94.4%, and 48 m 44.4/100% (AUC = .935, p = .009, CI95% .855, 1.015).Conclusions
A Δ6MWT of approximately 45 m appears to exceed measurement error and be associated with significant changes in either aerobic capacity and/or HRQL.Key Words: heart failure, six-minute walk test, clinically meaningful change, minimum detectable difference 相似文献994.
Delphinus EM Sayers MG 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(2):212-222
Putting proficiency is a key determinant of golfing success and yet minimal biomechanical research has been published on this important skill. Little is known about the motion and coordination of the pelvis and trunk during the putting motion. The purpose of this study was to present detailed three-dimensional (3D) kinematic profiles of the pelvis and trunk during the putting motion, and to determine if differences in kinematics exist between proficient and non-proficient golfers. A 3D analysis (100 Hz) was conducted on 10 single figure handicap golfers using a six-camera motion capture system. Participants completed 18 putts (2 m) towards a cup in an indoor facility and were subsequently divided into two groups based on putting proficiency (Proficient: >79%; Non-proficient: <79%). Variables assessed were the linear movements of the centre of mass (COM) and head, and the angular movements of the pelvis and trunk. Effect size statistics showed that the Proficient putters tended to move predominantly in the frontal plane (towards the target), while the non-proficient putters moved more sagittally. In addition, the Non-proficient putters recorded greater movement variability. The implications of this study suggest that putting proficiency is enhanced when the COM moves towards the target. 相似文献
995.
新年伊始,先给各位读者拜个晚年,祝读者们在新的一年里步步高升,心想事成!
除了平常的1V1外,2V2赛事也引起了许多war3爱好者的关注,一些赛事例如一周一赛的双打杯,每周都有许多玩家自行组队‘基’情参赛,而在职业圈里也有Beiieve这位韩国大神参加,这也让比赛不缺乏亮点,而每周的皇冠录像中更是频频出现精彩的2V2录像,这也使得2V2比赛得到了广大玩家进一步的关注,也让War3所带给大家的魅力得以传承。 相似文献
996.
本次经典回顾为大家带来的是06年时的一场天王对决,比赛双方分别是巫妖王Sweet和兽王Grubby。在那个剑圣还没有被开发出来的年代里,兽人部落的首发英雄多半都是当时的领袖FS(先知),其独有的幽灵狼在前期能给予对手强有力的压制效果,而第二技能闪电链则是部落仅有的AOE神技之一,在当时配合上老牛的冲击波,威力十足,不过在当时几近无敌的吹风流和Sky一波流面前,兽人部落的抬头之日还没有到来。另一边亡灵当时的情况则是 相似文献
997.
998.
张中菊 《Journal of Zhangzhou Technical Institute》2010,12(2):107-109
通过对高职院校学生未来职业特点进行分析,提出结合学生专业特点、职业场景、职业素养和职业保健四个方面来开展职业实用性体育.以期提高他们的职业适应能力,增强学生职业劳动的身体素质和心理承受能力. 相似文献
999.
G. Daniel SHENG 《浙江大学学报(A卷英文版)》2010,11(5):356-362
1-(2-chlorophenyl) ethanol (CPE) is of health and environmental concern due to its toxicity and its use as an intermediate in pharmaceutical manufacturing. The current work deals with the catalytic reductive dechlorination and detoxification of CPE by Pd/Fe bimetal. CPE was effectively dechlorinated to l-phenyl ethanol (PE) accompanied by the equivalent release of chloride. The extent of CPE dechlorination increased with temperature, Fe dosage and Pd loading. A decrease in solution pH increased CPE dechlorination, resulting presumably from an increase in hydrogen production. Under the specific conditions of 20 g/L Pd/Fe, 0.10% Pd (w/w) and initial pH 5-6, the CPE dechlorination was completed within 145 rain. The dechlorination followed a pseudo-first-order kinetics with an activation energy of 56.7 kJ/mol. The results of toxicity testing showed that CPE was very toxic to Chlorella, whereas PE showed little toxicity. The toxicity of the reaction solution declined gradually and the promoting effects on Chlorella intensified consequently with the dechlorination process. Thus, the reductive dechlorination of CPE to PE by Pd/Fe was a detoxification process. It may be used to effectively reduce the toxicological effects of CPE-contaminated wastewater, thereby enhancing the performance of subsequent biological processes in wastewater treatment. 相似文献
1000.
Bülent 《浙江大学学报(A卷英文版)》2010,11(2):106-114
In this study, an electro-mechanical valve (EMV) system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition (SI) engine was designed and constructed. An engine with the EMV system and a standard engine were tested to observe the effects of the EMV on engine performance and emissions at different speeds under full load. The EMV engine showed improved engine power, engine torque and break specific fuel consumption (BSFC). A 66% decrease in CO emissions was also obtained with the EMV system, but hydrocarbons (HC) and NOx emissions increased by 12% and 13% respectively. 相似文献