不同膝角静态蹲跳的生物力学研究

运用三维测力系统,对不同膝角静态蹲跳的测试结果进行比较分析：着重讨论了最大力值、蹬伸时间、冲量值等主要生物力学指标的变化规律及其对纵跳高度的影响。     

The biomechanics of the triple jump: A review

Abstract

The purpose of this paper is to review the published opinions of coaches and the findings of scientists concerning the techniques used in the triple jump, and to identify promising avenues for future research on the subject. A model is developed to identify those factors that have a causal role in determining the official distance of a triple jump. This model is then used as a basis for the subsequent review. The review itself considers each of the biomechanical factors identified in the model, some additional factors reported in the literature, and selected characteristics of triple jumping techniques. It is concluded that research on triple jump techniques has been sparse and has had little impact on practice. Identification of the individual attributes that determine the optimum ratio of the phase distances for a given athlete, the loads to which the supporting legs are subjected and the control of balance during a triple jump are seen as challenging and potentially useful topics of future research.     

Side-to-side differences in lower extremity biomechanics during multi-directional jump landing in volleyball athletes

Side-to-side differences of lower extremities may influence the likelihood of injury. Moreover, adding the complexity of jump-landing direction would help to explain lower extremity control during sport activities. The aim was to determine the effects of limb dominance and jump-landing direction on lower extremity biomechanics. Nineteen female volleyball athletes participated. Both dominant limbs (DLs) and non-dominant limbs (NLs) were examined in single-leg jump-landing tests in four directions, including forward (0°), diagonal (30° and 60°), and lateral (90°) directions. Kinematic marker trajectories and ground reaction forces were collected using a 10 camera Vicon system and an AMTI force plate. Repeated measures ANOVA (2?×?4, limb?×?direction) was used to analyse. The finding showed that, at peak vertical GRF, a significant interaction of limb dominance and direction effects was found in the hip flexion angle and lower extremity joint kinetics (p?<?.05). NLs and DLs exhibited significantly different strategies while landing in various directions. Significantly higher increase of ankle dorsiflexion angle was observed in lateral direction compared to other directions for both DLs and NLs (p?<?.05). Increasingly using ankle dorsiflexion was observed from the forward to the lateral direction for both DLs and NLs. However, NLs and DLs preferentially used different strategies of joint moment organization to respond to similar VGRFs in various directions. The response pattern of DLs might not be effective and may expose DLs to a higher injury risk, especially with regard to landing with awkward posture compared with NLs.     

对我国优秀女子三级跳远运动员三次起跳阶段动作结构的研究

运用文献资料、影片解析与数理统计等研究方法，对我国优秀女子三级跳远运动员三次起跳阶段的动作结构进行了定量描述和分析。结果表明，我国女子三级跳远运动员第一跳、第二跳起跳的动作结构，有利于保持水平速度，第三跳起跳的动作结构有利于增大冲量。但由于女运动员没有熟练地掌握技术，加之支撑能力较差，从而造成第二、三跳缓冲加深，这样不仅损失了水平速度，而又也没有获得较大的垂直速度和合理的腾起角度。     

国内三级跳远运动员起跳时间与腾空时间分析

对参加2013年全国田径锦标赛暨全运会预选赛女子三级跳远决赛的5名健将级运动员三跳中起跳时间与腾空时间进行运动学分析,并与国外优秀三级跳远运动员的相关参数进行比较研究,找出我国三级跳远运动员起跳与腾空技术上存在的不足,以期为改进我国三级跳远运动员的起跳与腾空技术、进一步提高运动成绩提供技术上的支持。     

负荷时间长短对纵跳能力影响的动力学研究

分析受试者在功率自行车上不同运动负荷时间后纵跳的动力学特征变化规律 ,研究结论 :①大强度持续运动约 3min左右 ,纵跳的爆发力、平均功率、平均力值等动力学指标显著上升 ;运动 5min后 ,上述指标的变化情况正好相反 ;②只有在适宜的运动负荷时间后 ,纵跳的动力学特征才进入有利于运动能力发挥的较好的组合状态     

Spike jump biomechanics in male versus female elite volleyball players

ABSTRACT

There are well-known biological differences between women and men, especially in technical-coordinative variations that contribute to sex differences in performance of complex movements like the most important offensive action in volleyball, the spike jump. The aim of this study was to investigate sex-dependent performance and biomechanical characteristics in the volleyball spike jump. Thirty female and male sub-elite volleyball players were analysed while striking a stationary ball with maximal spike jump height. Twelve MX13 Vicon cameras with a cluster marker set, two AMTI force plates, surface EMG, and a Full-Body 3D model in Visual3D were used. Main findings include sex differences (P< .05) in jump height (pη² = .73), approach [speed (pη² = .61), step length], transition strategy [plant angle, neuromuscular activation (pη² = .91), horizontal force maxima and impulses], acceleration distances [centre of mass displacement (pη² = .21), minimal knee and hip angles], use of torso and arms [incline, angular velocity (pη² = .23)]. Correlations support that the results cannot be explained fully by strength and power differences between sexes but represent the product of technical-coordinative variations. Their relevance is acknowledged for both sexes and numerous performance determinants displayed sex differences. The integration of such attributes into sex-specific training seems promising but its effect requires further investigation.     

Effects of official youth taekwondo competitions on jump and strength performance

Abstract

The aim of this study was to investigate differences in athletes’ (7 females, 10 males) motor performances (countermovement jump and handgrip) before and after official youth (13–14 years) taekwondo matches. Exercise load was evaluated by means of the heart rate responses during the match. Independent of round and gender, during the competitions mean heart rate was 187 beats·min^?1 (s=11). During the match, the frequency of heart rate responses above 85% of an individual's maximum heart rate was 77% (s=27). Jump performances showed differences for gender (P=0.044; ES = 0.47) and its interaction with session (P=0.045; ES = 0.49). Female athletes’ post-match countermovement performances were no different from their pre-match performances (pre and post: 22 cm, s=2), whereas male athletes post-match performances (28 cm, s=6) were better than their pre-match performances (25 cm, s=6). Handgrip performances related to the body mass of the athletes showed main effects for session (P=0.017; ES = 0.20) and for gender (P=0.026; ES = 0.47), with no significant interaction. Male athletes showed higher handgrip values (5.8 N·kg^?1, s=0.6) than their female counterparts (5.1 N·kg^?1, s=0.7). For absolute grip strength performances, values were higher pre-match (290.3 N, s=61.4) than post-match (272.4 N, s = 58.3). The heart rate responses indicate that official youth taekwondo competition imposes a high load on athletes. In particular, post-match decreases in isometric grip strength suggest that coaches should better prepare their very young athletes to prevent reductions in muscle force during fighting. Considering that lower limb power remained unaffected or increased depending on gender, further research in this area is strongly recommended.     

不同下肢力量训练形式对原地纵跳成绩的影响

本文通过文献资料珐、实验法和教理统计珐,以西安体育学院2010级20名休闲体育专业的学生为研究对象（A粗【单纯向心收缩】10人,B组【离心＋向心收缩】10人）,分别采用两种不同肌肉收缩形式进行为期8周的下肢力量训练。实验前后采用瑞士KILSTER9287C型三堆渊力台,对实验对象的静止纵跳、反弹从跳进行动力学分析。     

Enhanced jump performance when providing augmented feedback compared to an external or internal focus of attention

Factors such as an external focus of attention (EF) and augmented feedback (AF) have been shown to improve performance. However, the efficacy of providing AF to enhance motor performance has never been compared with the effects of an EF or an internal focus of attention (IF). Therefore, the aim of the present study was to identify which of the three conditions (AF, EF or IF) leads to the highest performance in a countermovement jump (CMJ). Nineteen volunteers performed 12 series of 8 maximum CMJs. Changes in jump height between conditions and within the series were analysed. Jump heights differed between conditions (P < 0.001), resulting in best performance with AF (32.04 ± 7.11 cm), followed by EF (31.21 ± 6.67 cm) and IF (30.77 ± 6.87 cm). Significantly different (P < 0.001) within-series effects of higher jump heights at the end of the series in AF (+1.60%) and lower jump heights at the end of the series in EF (?1.79%) and IF (?1.68%) were observed. Muscle activity did not differ between conditions. The differences between conditions and within the series provide evidence that AF leads to higher performance and better progression within one series than EF and IF. Consequently, AF seems to outperform EF and IF when maximising jump height.     

速度在三级跳远中的重要作用

研究认为,速度型三级跳远技术成为现在和未来发展的必然趋势。其训练应围绕着以速度为核心,以减少水平速度的损失为前提,缩短第一跳,加大第三跳。     

第 29 届奥运会男女跳远和三级跳远运动员决赛时竞技能力表现特征的比较研究

运用文献资料法、比较分析法、现场测试等研究方法,对第29届奥运会男女跳远和三级跳远决赛运动员的基本情况、前后三跳成绩、成功率、速度变化特征等内容进行研究.结果表明:男女跳远和三级跳远运动员的最佳竞技能力具有相对稳定的成熟期,男女跳远运动员的竞技能力达到个人最好成绩的97.59%和97.92%,其中第一、二跳是成功率最高的两个跳次,男子的最好成绩出现在第四和第六跳次,女子的最好成绩则出现在第二和第三跳次;男女三级跳远运动员的竞技能力高达个人最好成绩的98.78%和99.80%,最好成绩出现在第二和第三跳次;女子跳远和男女三级跳远运动员前三跳的助跑速度和最佳成绩均比后三跳要快、要好,而男子跳远运动员的情况则相反.     

对我国优秀跳远、三级跳运动员的运动损伤流行病学调查与分析

为了最大限度地减少跳远和三级跳运动员运动损伤的发生率,本文通过对我国165名优秀跳远和三级跳运动员进行了调查及病因分析,对几个相关的引起运动员运动损伤的原因及防伤措施进行了探讨。     

An analysis of two styles of arm action in the vertical countermovement jump

The aim of this study was to determine the effect of two arm swing techniques, the simultaneous arm swing and the early arm swing, on vertical countermovement jump performance and on the contribution of the arms to vertical movement at the centre of mass (CM) during the propulsion phase. Participants were 28 athletes practicing sports in which the vertical jump constitutes a basic ability. Ground reaction forces were recorded by a force platform and the sagittal plane motion was recorded by a video camera. Although at take-off the vertical velocity (2.7 ± 0.2 m/s for simultaneous technique vs. 2.8 ± 0.2 m/s for early technique; p = 0.040) and position (1.18 ± 0.06 m for simultaneous vs. 1.17 ± 0.05 m for early; p = 0.033) of the CM were significantly different, no difference was observed in jump height (1.56 ± 0.01 m in both techniques). The arm action differed during the initial and final propulsion phases in both styles but the accumulated vertical contribution was similar. The practical implication in sports is that the use of the arm-swing technique to reach the maximum jump height should be determined by tactical demands instead of the technical execution of the arms.     

Validity of a contact mat and accelerometric system to assess countermovement jump from flight time

Countermovement jump (CMJ) height is an important parameter in physical performance. This study compared CMJ height measured using ChronoJump contact mat (CJ) and Myotest accelerometer (MT) systems with a force platform (FP). Thirty recreationally active adults (32.1 ± 10.4 years, 75.9 ± 12.0 kg, 173.2 ± 6.3 cm) completed a CMJ protocol where height was simultaneously recorded using the three systems. CJ and MT measures were strongly and significant correlated (r = 0.65, 0.66, respectively; p < 0.05) with FP. CJ-derived measures were not significantly different to FP measures (p > 0.05), yet MT-derived measures were significantly different from those obtained using the FP (p < 0.05). Systematic bias was observed between FP and the CJ and between FP and MT. This study demonstrates the validity of CJ and MT systems for the assessment of CMJ height. Systematic bias and between-device differences in measurement should be considered when interpreting and comparing data from these devices.     

Sleep restriction impairs maximal jump performance and joint coordination in elite athletes

ABSTRACT

The study objective was to examine the effects of three days of sleep restriction on maximal jump performance and joint coordination. Eleven elite cyclists obtained a one-week baseline of habitual sleep then restricted sleep to 4 h/night (SR) for three nights assessed through self-report and actigraphy. Pre and post-intervention measures were a box drop maximal vertical jump with 3D motion capture to assess physical performance and biomechanical changes, and Psychomotor Vigilance Task (PVT) assessed changes in response time. Associations between biomechanical, physical, and cognitive performance measures were assessed. Participants restricted reported sleep from 7.4 ± 0.5 h/night at baseline to 4.0 ± 0.2 h/night and actigraphy indicated 6.7 ± 0.7 to 3.7 ± 0.2 h/night. Following SR, jump height decreased (0.44 ± 0.09 vs. 0.42 ± 0.10 m, p = 0.02, g = 0.21). Hip sagittal/knee frontal (Δ15.5°, p = 0.04, g = 0.40) and hip frontal/knee frontal (Δ11.0°, p < 0.01, g = 0.44) plane coordination variability increased after SR. Hip sagittal/knee frontal plane coordination variability after SR was associated with increasingly slower PVT response time (r = 0.63, p = 0.03). These findings suggest SR for three days decreased maximal jump performance. SR increased joint coordination variability and was associated with greater impairment in response time. SR leads to deviations from preferred movement patterns, which may have implications for decrements in athlete performance and increased injury risk.     

Reaction Time and Anticipation Time: Effects of Development

Abstract

The developmental nature of reaction time (RT) and anticipation timing (AT) performance, as well as the relationship between them, was investigated using 15 male and 15 female subjects at each of five age levels—7, 9, 11, 13, and 20 yrs. Each subject was given 40 trials for both RT and AT performance with task order counterbalanced. Results indicated that as age increased RT decreased, with males having more rapid RT than females. The two younger age groups differed from the three older groups on AT performance. RT was significantly correlated with AT (|CE| measure) for the 7, 9, and 11 yr old males but not in any other age by gender condition. Apparently neither young males nor young females have a good motor plan in memory to control AT performance. However, the more rapid RT (and thus better response initiation) of the males allows better AT performance at the younger ages. Beginning about 10–11 yrs of age, better motor plans are developed in children's memory system, leading to less reliance on rapid RT for good AT performance, and thus the correlation between RT and AT performance is not present.     

跳高起跳垂直速度的生物力学研究

采用两台SONY摄像机对我国优秀男子跳高运动员的试跳进行现场同步拍摄，选取有关运动学参数与国外优秀运动员做对比分析。研究结果：我国运动员起跳着地瞬间质心向下的垂直速度较小，符合我国运动员的身体特点；在起跳阶段，我国运动员双臂和摆动腿的摆动速度与优秀运动员相比较低，主要与起跳腿的专项力量素质有关；我国运动员起跳时间与国外优秀运动员相比较短，与蹬伸距离较短有关。相对缩小起跳的缓冲时间，有利于提高起跳的垂直速度。决定跳高起跳垂直速度的诸因素均与起跳腿的专项力量素质有关。     

对三级跳远运动中三跳比例的再认识

三级跳远起源于爱尔兰,现代三级跳远的发展是随着现代奥林匹克运动的兴起、发展而兴盛起来的,是运动员经过助跑,沿直线连续进行三次水平跳跃的田径项目。运动员在高速助跑的情况下,要完成三次身体运动方向的改变和一系列相适应的技术动作,任何一个环节出现错误都可能导致全跳失