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1.
This study aimed to identify the continuous ground reaction force (GRF) features which contribute to higher levels of block phase performance. Twenty-three sprint-trained athletes completed starts from their preferred settings during which GRFs were recorded separately under each block. Continuous features of the magnitude and direction of the resultant GRF signals which explained 90% of the variation between the sprinters were identified. Each sprinter’s coefficient score for these continuous features was then input to a linear regression model to predict block phase performance (normalised external power). Four significant (p < 0.05) predictor features associated with GRF magnitude were identified; there were none associated with GRF direction. A feature associated with greater rear block GRF magnitudes from the onset of the push was the most important predictor (β = 1.185), followed by greater front block GRF magnitudes for the final three-quarters of the push (β = 0.791). Features which included a later rear block exit (β = 0.254) and greater front leg GRF magnitudes during the mid-push phase (β = 0.224) were also significant predictors. Sprint practitioners are encouraged, where possible, to consider the continuous magnitude of the GRFs produced throughout the block phase in addition to selected discrete values.  相似文献   

2.
Abstract

Developed from traditional Chinese martial arts, Tai Chi exercise includes different forms and interactive Push Hands but biomechanical analyses have focused on the former only. To analyse the techniques of Push Hands, an experienced master was asked to defend pushing by four opponents. Movements were videotaped and digitized using a motion analysis system. Surface electrodes were used to record the electromyographic activity of ten muscle groups. Two force plates were used to measure the ground reaction force on each foot. Inexperienced individuals performed the same procedure to serve as the control group. The results indicate that the master adopted a postural adjustment to maintain balance. A clear shift of body weight from the front to the rear foot and mediolateral displacement of the centre of gravity was observed. Low electromyographic activity was observed in the upper body muscle groups, while high electromyographic activity was observed in the right rectus femoris and very high activity in the left rectus femoris during the defence. All inexperienced participants lost their balance in resisting pushing. It is concluded that the Tai Chi defensive technique includes a subtle postural adjustment that slightly changes the pushing force direction, and allows the rear leg to resist the incoming force.  相似文献   

3.
马旭君 《浙江体育科学》2010,32(1):82-84,97
元认知包括元认知知识、元认知体验和元认知监控。太极拳是一种强调自我锻炼的运动,太极拳的智慧源自锻炼者自我认识的深入,源自自身的“体悟”累积。太极拳智慧主要表现为：认识智慧、内劲智慧和修养智慧。运用元认知理论对太极拳智慧提升进行阐释。在太极拳练习中,如何用“意”体现着锻炼个体如何积极运用元认知知识、元认知体验和元认知监控功能的实现水平和能力。太极拳功夫造诣越深,锻炼者的元认知越发达,其自身的悟性越强,智慧也就越多。太极拳是一门名副其实的智拳。  相似文献   

4.
谈太极推手的合理用力   总被引：1，自引：0，他引：1  
文章从多方面对太极推手的合理用力进行了分析总结,认为:太极推手用手要张弛交替,劳逸结合,以逸待劳,不妄发击,充分利用人体重力和势能作用,要不失时机地利用运动的惯性用力,合理运用摩擦力,要巧用螺旋力,以供学习太极拳的爱好者借鉴。  相似文献   

5.
论陈式太极拳的腰裆功   总被引：1，自引：0，他引：1  
对在练习陈式太极拳中怎样掌握腰裆．对腰裆的练习要求及方法进行了论述与分析。认为无论是在盘架子还是在推手格斗中，腰与裆都应密切配合，而裆部的运行路线应该“锅底型”与“∞字型”相结合。  相似文献   

6.
周勇  孙雷  张珂 《福建体育科技》2012,31(2):25-26,29
目的:探讨太极拳锻炼对亚急性腰椎间盘突出患者的康复影响。方法:将60例受试者随机分为三组(各20例),A组为太极拳锻炼组,B组为手法治疗组,C组为静养恢复组;实验时间为5个月,期间对所有患者进行跟踪牵引复位和影像学监控,预防不良病变;实验前后测量受试者的腰椎疼痛指数和体成分,组间变化比较采用t检验,组间综合疗效比较采用x2检验。结果:A、B、C三组VAS均有所下降,下降幅度AB组极显著性大于C组,A组显著性大于B组;实验后A组体重和体脂百分比显著低于BC组;组间综合疗效比较,优良率A组好于B组,B组好于C组,组间比较具有显著差异性。结论:太极拳锻炼相对于手法治疗和静养恢复疗效更好,并能控制体成分的消极改变,更有利于康复和预防病症复发。  相似文献   

7.
Developed from traditional Chinese martial arts, Tai Chi exercise includes different forms and interactive Push Hands but biomechanical analyses have focused on the former only. To analyse the techniques of Push Hands, an experienced master was asked to defend pushing by four opponents. Movements were videotaped and digitized using a motion analysis system. Surface electrodes were used to record the electromyographic activity of ten muscle groups. Two force plates were used to measure the ground reaction force on each foot. Inexperienced individuals performed the same procedure to serve as the control group. The results indicate that the master adopted a postural adjustment to maintain balance. A clear shift of body weight from the front to the rear foot and mediolateral displacement of the centre of gravity was observed. Low electromyographic activity was observed in the upper body muscle groups, while high electromyographic activity was observed in the right rectus femoris and very high activity in the left rectus femoris during the defence. All inexperienced participants lost their balance in resisting pushing. It is concluded that the Tai Chi defensive technique includes a subtle postural adjustment that slightly changes the pushing force direction, and allows the rear leg to resist the incoming force.  相似文献   

8.
太极拳其根在脚,发于腿,主宰于腰,形于手指。它集强身健体、祛病延年、道德修养等优点于一体,备受广大体育爱好者的喜爱。太极拳要讲大松大柔,很多专业著作中甚至将松柔强调为太极拳的灵魂,松柔有很多诀窍,其中有方法问题,当然也有层次理解的问题。太极拳中的＂松＂是练习太极拳的关键之一＂,松＂在一定程度上对身体健康,体质的改善具有很大的帮助。文章运用文献资料法,对太极拳的＂松＂对人体的影响进行了分析,从生理学角度分析并阐明了松的作用机理,并提出相关建议,以帮助练习者更好的理解松的意义,并能在实践中加以运用。  相似文献   

9.
This study assessed the validity of a tri-axial accelerometer worn on the upper body to estimate peak forces during running and change-of-direction tasks. Seventeen participants completed four different running and change-of-direction tasks (0°, 45°, 90°, and 180°; five trials per condition). Peak crania-caudal and resultant acceleration was converted to force and compared against peak force plate ground reaction force (GRF) in two formats (raw and smoothed). The resultant smoothed (10 Hz) and crania-caudal raw (except 180°) accelerometer values were not significantly different to resultant and vertical GRF for all running and change-of-direction tasks, respectively. Resultant accelerometer measures showed no to strong significant correlations (r = 0.00–0.76) and moderate to large measurement errors (coefficient of variation [CV] = 11.7–23.9%). Crania-caudal accelerometer measures showed small to moderate correlations (r = ? 0.26 to 0.39) and moderate to large measurement errors (CV = 15.0–20.6%). Accelerometers, within integrated micro-technology tracking devices and worn on the upper body, can provide a relative measure of peak impact force experienced during running and two change-of-direction tasks (45° and 90°) provided that resultant smoothed values are used.  相似文献   

10.
Abstract

Researchers and clinicians have suggested that overuse injuries to the lower back and lower extremities of figure skaters may be associated with the repeated high impact forces sustained during jump landings. Our primary aim was to compare the vertical ground reaction forces (GRFs) in freestyle figure skaters (n = 26) and non-skaters (n = 18) for the same barefoot single leg landing on a force plate from a 20 cm platform. Compared with non-skaters, skaters exhibited a significantly greater normalised peak GRF (3.50 ± 0.47 × body weight for skaters vs. 3.13 ± 0.45 × body weight for non-skaters), significantly shorter time to peak GRF (81.21 ± 14.01 ms for skaters vs. 93.81 ± 16.49 ms for non-skaters), and significantly longer time to stabilisation (TTS) of the GRF (2.38 ± 0.07 s for skaters vs. 2.22 ± 0.07 s for non-skaters). Skaters also confined their centre of pressure (CoP) to a significantly smaller mediolateral (M–L) (25%) and anterior–posterior (A–P) (40%) range during the landing phase, with the position of the CoP located in the mid to forefoot region. The narrower and more forward position of the CoP in skaters may at least partially explain the greater peak GRF, shorter time to peak, and longer TTS. Training and/or equipment modification serve as potential targets to decrease peak GRF by distributing it over a longer time period. More comprehensive studies including electromyography and motion capture are needed to fully characterise the unique figure skater landing strategy.  相似文献   

11.
Chronic elbow injuries from tumbling in female gymnastics present a serious problem for performers. This research examined how the biomechanical characteristics of impact loading and elbow kinematics and kinetics change as a function of technique selection. Seven international-level female gymnasts performed 10 trials of the round-off from a hurdle step to flic-flac with ‘parallel’ and ‘T-shape’ hand positions. Synchronized kinematic (3D-automated motion analysis system; 247 Hz) and kinetic (two force plates; 1,235 Hz) data were collected for each trial. Wilcoxon non-parametric test and effect-size statistics determined differences between the hand positions examined in this study. Significant differences (p < 0.05) and large effect sizes (ES>0.8) were observed for peak vertical ground reaction force (GRF), anterior–posterior GRF, resultant GRF, loading rates of these forces and elbow joint angles, and internal moments of force in sagittal, transverse, and frontal planes. In conclusion, the T-shape hand position reduces vertical, anterior–posterior, and resultant contact forces and has a decreased loading rate indicating a safer technique for the round-off. Significant differences observed in joint elbow moments highlighted that the T-shape position may prevent overloading of the joint complex and consequently reduce the potential for elbow injury.  相似文献   

12.
研究目的:研究长期练习太极拳、交谊舞、慢走对老年女性平衡能力的影响。研究方法:采用秒表和芬兰Good Balance平衡训练测试系统对太极拳组(15名)、交谊舞组(15名)和慢走组(14名)老年女性进行平衡能力的测试。实验结果:在闭眼单足站立中,太极拳组与慢走组具有显著性差异。在静态平衡能力测试中,太极拳组与慢走组在双脚睁眼、双脚闭眼、单腿睁眼中出现显著性差异。交谊舞组与慢走组在半脚测试中出现显著性差异。在动态平衡能力测试中,时间T与人体重心COP移动的总距离D,太极拳组与慢走组有显著性差异。COP在X轴上的移动距离MLD,太极拳组与慢走组,交谊舞组与慢走组之间都具有显著性差异。结论:太极拳和交谊舞在改善老年人平衡能力方面效果都优于慢走;太极拳和交谊舞具有良好的防止老年人跌倒的功效。  相似文献   

13.
背景:近年来有关太极拳治疗腰痛患者的实验研究不断增多,受限于实验条件的差异,不同的实验的总效果量难以衡量,不同类型的实验也难以横向比较。目的:本研究使用元分析从下背痛患者疼痛程度、腰椎功能两个方面,评价太极拳及其联合治疗对下背痛患者的干预效果。方法:检索了Web of Science、PubMed、中国知网、万方4个电子数据库,检索2020年1月13日前发表的所有研究。由两名研究人员独立完成研究检索、研究选择、数据提取以及质量评估。结果:共纳入16项随机对照试验进行meta分析。研究结果显示,对比其他康复治疗,太极拳及其联合治疗可显著减轻患者疼痛程度MD(95%CI)=-1.15[-1.61,-0.69],P<0.00001。提高腰椎功能(MD(95%CI)=-1.38[-1.70,-1.06],P<0.00001)。结论:1、太极拳及其联合治疗减轻患者疼痛程度的效果显著优于其他康复方案;亚组分析表明,太极拳治疗腰椎间盘突出的效应量大于腰肌劳损与非特异性下背痛。2、对比核心稳定性训练,太极拳提高下背痛患者功能的效果显著。  相似文献   

14.
ABSTRACT

The current study aimed to describe the distribution of physical and technical performance during the different phases of play in professional Australian Football. The phases of play (offence, defence, contested play, umpire stoppages, set shots and goal resets) were manually coded from video footage for a single team competing in 18 matches in the Australian Football League. Measures of physical performance including total distance (m), average speed (m · min?1), low-speed running (LSR, <14.4 km h?1), high-speed running (HSR, >14.4 km h?1), accelerations (2.78 m · s?2) and decelerations (?2.78 m · s?2) were derived from each phase of play via global positioning system (GPS) devices. Technical skill data including tackles, handballs and kicks were obtained from a commercial statistics provider and derived from each phase of play. Linear mixed-effects models and effect sizes were used to assess and reflect the differences in physical and technical performance between the six phases of play. Activity and recovery cycles, defined as periods where the ball was in or out of play were also described using mean and 95% confidence intervals. The analysis showed that several similarities existed between offence and defence for physical performance metrics. Contested play involved the highest total distance, LSR, accelerations, decelerations and tackles compared to all other phases. Offence and defence involved the highest average speed and HSR running distances. Handballs and kicks were highest during offence, while tackles were highest during contested play, followed by defence. Activity and recovery cycles involved mean durations of ~110 and ~39 s and average speeds of ~160 and ~84 m · min?1, respectively. The integration of video, GPS and technical skill data can be used to investigate specific phases of Australian Football match-play and subsequently guide match analysis and training design.  相似文献   

15.
ABSTRACT

This study identified the effect of badminton lunging directions on impact characteristics, joint kinetics and measurement reliability. A total of 14 badminton players performed 20 lunges in both forehand and backhand sides. Ground reaction force (GRF) and three-dimensional joint moment variables were determined for further analyses. Paired t-tests and Wilcoxon signed-rank tests were performed to determine any differences between the two lunge directions and intra-class correlation (ICC) and sequential averaging analysis (SAA) were used to estimate the minimum number of trials. Compared to the forehand side, participants experienced significantly larger total GRF impulse (+ 3.8%, p = 0.021) and transverse moment (hip + 63.5%, p < 0.001; knee + 80.7%, p = 0.011), but smaller hip (?7.7%), knee (?18.7%) and ankle frontal moments (?58.0%, p < 0.05) in backhand lunges. The minimum number of trials was similar for both lunge directions, as the averaged absolute differences was less than one in both ICC and SAA. Furthermore, smaller minimal number of trials was determined by the ICC (7.9–8.0), compared with the SAA approach (9.5–10.3). Lunge direction would influence GRF and joint loading, but not on the measurement reliability. These results give important insights to establish performance or equipment evaluation protocols during badminton lunges.  相似文献   

16.
文章对科学发展观视野下的高校太极拳社团的发展进行研究,建议高校从坚持正确的政治方向、加强思想组织建设,加大投入、注重对学生社团的指导与扶持,认真掌握好社团发展的前进方向,加强社团干部建设、提高奉献服务意识等方面着手,以期对太极拳社团在新形势下健康的发展有所裨益。  相似文献   

17.
This study analysed the effects of bilateral and non-dominant practice on novice practitioners’ lateral preference for judo skills in a combat context (i.e., randori). Thirty sports sciences students (22 men and 8 women; mean age 19 ± 1 years) with right hand, foot, and counterclockwise rotation preferences were divided into 3 groups: bilateral (BG; n = 8), non-dominant (NDG; n = 11), and control (CG; n = 11). Participants received 8 weeks of training at a rate of 3 days per week. The NDG was trained to perform judo skills exclusive with their non-dominant side, while the BG performed every task symmetrically. Before and after training, participants were recorded during two 3-min randoris to obtain the percentage of their engagement in dominant side actions. Pretest percentages were 73.1 ± 19.9%, 77.8 ± 18.8%, and 68.9 ± 27.2% for BG, NDG, and CG, respectively. Post-test values were 75.0 ± 15.6%, 23.3 ± 27.9%, and 72.2.9 ± 20.4%, respectively. Significant differences were observed between NDG and each of the other groups after the training. Changes from pretest were only significant for NDG (P = 0.003). These results suggest that lateral preference among novice judo practitioners during randori can be modulated by the type of practice.  相似文献   

18.
运用摄影测量法和Novel Pedar-X足底压力测试系统采集了16名太极拳练习者在太极拳运动和正常步行中足底压力和运动影像信息,并对两种运动方式的单脚支撑姿势持续时间指标进行对比分析。研究表明:与正常步行相比,在太极拳运动中单脚支撑姿势总的持续时间所占比例(标准化值)较少(P<0.05);单次单脚支撑姿势平均持续时间较长(P<0.01);认为太极拳运动可以提高人体单脚平衡能力。另外还发现太极拳运动和正常步行中地面反作用力都在不断变化;太极拳运动中地面反作用力小于其正常步行值。  相似文献   

19.
PurposeThe purpose of the present study was to examine the effects of a 24-week Tai Chi exercise intervention on balance and other physical changes such as flexibility and reaction time (RT) among healthy older males.MethodsThirty-eight male subjects aged 55–65 years without prior Tai Chi experience were recruited from a local community in Shanghai, China. A 60-min Tai Chi exercise session was performed three times a week for 24 weeks. Changes in RT, sit-and-reach flexibility and balance (static balance with eyes open and closed respectively) were measured before and after the Tai Chi intervention.ResultsAfter the 24-week Tai Chi intervention, the choice RT (p < 0.05) decreased, and sit-and-reach flexibility improved (p < 0.01) over the pre-test (7.8±6.2 vs. 7.1±3.0cm). Sway length, area, X-axis deviation amplitude and Y-axis deviation amplitude performance decreased significantly after the intervention with a double-foot stance with eyes open (p < 0.05). Sway length, area and average sway speed showed a statistically significant decrease after the intervention with the double-foot stance with eyes closed. In the single-foot stance with eyes open condition, sway length and average sway speed showed a statistically significant decrease (p < 0.05).ConclusionThe 24-week Tai Chi exercise intervention had a positive influence on balance control in older males.  相似文献   

20.
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 (COPap) displacement as well as a lower braking impulse than no-exercise group. Under the low illumination, Tai Chi exercise participants demonstrated higher COPap and mediolateral centre of pressure (COPml) 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 COPap displacement under low illumination to increase their stability during stair ascent.  相似文献   

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