试论肌肉放松对提高短跑成绩的重要性

本文就我国短跑教练员在训练中比较容易忽视的一个细节领域(肌肉协调放松能力),从短跑肌肉放松的意义、原理和国内外教练员对短跑中放松的认识等方面,采用观察法、专家咨询法、文献资料法,探讨了肌肉协调放松对提高短跑运动成绩的重要性。     

短跑运动员应加强肌肉放松能力

现代短跑运动的发展和提高很快,短跑技术更加符合运动生物力学和运动解剖学原理,要求技术以最佳的实效性和经济性完成练习,而全身高度协调、肌肉放松是完成练习经济性、节省化和效率化的基础。任何一个动作的协调完成都是肌肉在大脑皮层支配下紧张收缩与放松伸展合理交替运动的结果,即紧张的肌肉很快过渡到放松,放松的肌肉要很快地紧张收缩,这样动作才能协调,这在短跑中尤为重要。事实上,短跑成绩的好坏很大程度上取决于跑时动作的自然放松能力,必须放松那些不参与工作的肌肉,美国著名教练彼得·温特提出的“百分之九十定律”,就…     

浅谈少年短跑运动员放松能力的培养

在短跑中,＂放松＂技术已成为一项重要的技术因素。在短跑中放松可以使肌肉协调用力,增强关节的灵活性和柔韧性,增大运动幅度,通过放松可以使髋关节周围肌肉协调用力,可以使髋在运动中发挥最大的作用,以增强髋关节的运动能力。同时,＂放松＂可以促进运动员肌肉力量均衡发展,有利于肌肉力量充分发挥,以取得更好的成绩。     

放松对提高短跑成绩的作用

放松的短跑技术得不到锻炼会影响短跑成绩的提高，而充分的放松可使参与工作的肌肉即时得到调整，增强肌肉的收缩力，减少内阻力和能量消耗，从而提高短跑的运动成绩。     

对少年短跑运动员放松能力的理性心思考

为使少年短跑运动员掌握合理技术,打好技术基础,不断提高运动成绩,结合少年运动员训练实际,运用文献资料法对影响少年短跑运动员肌肉放松能力的生理机制、技术特点、少年运动员的训练特点等进行理论与实践分析。指出肌肉放松能力对于少年短跑运动员基础训练阶段技术训练的重要性,并提出培养少年短跑运动员放松能力的训练方法及训练建议。     

谈少年短跑运动员放松能力的培养

放松对于短跑运动员掌握合理技术,提高运动成绩是一个重要因素。本文对影响少年短跑运动员肌肉放松训练有关的生理机制、技术特点、少年运动员的训练特点进行分析,并提出培养少年短跑运动员放松能力的训练方法及训练建议。     

浅议放松技术与短跑速度的关系

浅议放松技术与短跑速度的关系广西师范大学秦伍生放松技术是指人体在快速运动中肌肉本身的放松能力．是短跑运动员充分挖掘最大潜力、创造优异成绩的关键技术。熟练的掌握放松技术，对于速度素质的发展、运动成绩的提高有着积极的影响．短跑速度的提高取快于步频和步长两...     

肌肉放松对提高短跑运动成绩的影响

肌肉的协调放松能力对于提高短跑运动员的成绩具有重要作用。章从改善肌肉的新陈代谢、改善神经的功能、减少肌肉的疲劳、有效延长肌肉的耐久力、增加肌肉的收缩力量、提高跑的实效性等方面，探讨了肌肉协调放松对提高短跑运动成绩的积极影响。     

对短跑放松技术的作用影响因素及训练方法的研究

通过文献法、观察法、经验总结等方法对短跑放松技术的作用、影响因素进行分析,提出了改进短跑放松技术、提高放松跑能力的基本策略和具体方法。一、放松技术在短跑中的作用1、在短跑中利用放松技术可以改善神经系统的功能,提高频率,发挥运动员的最大速度。2、使运动员能合理分配,尽可能减少多余的肌肉工作现象,合理地运用能量;促进全身血液循环,改善快速奔跑中肌肉的功能过程,提高速度耐力,提高运动     

试论短跑运动员协调放松能力的训练

运动员具有良好的放松能力有助于挖掘运动潜能和运动技术。在此，提示短跑运动员肌肉放松的训练方法，仅供参考。     

Relationship between the peak time of hamstring stretch and activation during sprinting

The purpose of this study was to investigate the time series relationships between the peak musculotendon length and electromyography (EMG) activation during overground sprinting to clarify the risk of muscle strain injury incidence in each hamstring muscle. Full-body kinematics and EMG of the right biceps femoris long head (BFlh) and semitendinosus (ST) muscles were recorded in 13 male sprinters during overground sprinting at maximum effort. The hamstring musculotendon lengths during sprinting were computed using a three-dimensional musculoskeletal model. The time of the peak musculotendon length, in terms of the percentage of the running gait cycle, was measured and compared with that of the peak EMG activity. The maximum length of the hamstring muscles was noted during the late swing phase of sprinting. The peak musculotendon length was synchronous with the peak EMG activation in the BFlh muscle, while the time of peak musculotendon length in the ST muscle occurred significantly later than the peak level of EMG activation (p < 0.05). These results suggest that the BFlh muscle is exposed to an instantaneous high tensile force during the late swing phase of sprinting, indicating a higher risk for muscle strain injury.     

Muscle activity in sprinting: a review

The use of electromyography (EMG) is widely recognised as a valuable tool for enhancing the understanding of performance drivers and potential injury risk in sprinting. The timings of muscle activations relative to running gait cycle phases and the technology used to obtain muscle activation data during sprinting are of particular interest to scientists and coaches. This review examined the main muscles being analysed by surface EMG (sEMG), their activations and timing, and the technologies used to gather sEMG during sprinting. Electronic databases were searched using ‘Electromyography’ OR ‘EMG’ AND ‘running’ OR ‘sprinting’. Based on inclusion criteria, 18 articles were selected for review. While sEMG is widely used in biomechanics, relatively few studies have used sEMG in sprinting due to system constraints. The results demonstrated a focus on the leg muscles, with over 70% of the muscles analysed in the upper leg. This is consistent with the use of tethered and data logging EMG systems and many sprints being performed on treadmills. Through the recent advances in wireless EMG technology, an increase in the studies on high velocity movements such as sprinting is expected and this should allow practitioners to perform the analysis in an ecologically valid environment.     

通过下肢肌电观察对部分短跑专门力量练习的分析

应用肌电图仪对短跑运动员做跨步跳、单足跳、负重蹲起等专门力量练习时进行了下肢肌电观察,并且与他们在短跑时所测得的肌电图做了比较。结果发现目前国内经常采用的这些专门力量练习在肌肉活动和技术结构上与短跑途中跑有明显差异,不利于短跑途中跑正确技术的训练。文中就短跑专门力量练习的选用提出了一些参考意见。     

Reactive and eccentric strength contribute to stiffness regulation during maximum velocity sprinting in team sport athletes and highly trained sprinters

ABSTRACT

This study investigated the role of reactive and eccentric strength in stiffness regulation during maximum velocity sprinting (Vmax) in team sport athletes compared with highly trained sprinters. Thirteen team sport athletes and eleven highly trained sprinters were recruited. Vmax was measured using radar, and stiffness regulation was inferred from modelled vertical and leg spring stiffness. Reactive strength (RSI) was determined from a 0.50 m drop jump, and an eccentric back squat was used to assess maximum isoinertial eccentric force. Trained sprinters attained a higher Vmax than team sport athletes, partly due to a briefer contact time and higher vertical stiffness. Trained sprinters exhibited a moderately higher RSI via the attainment of a briefer and more forceful ground contact phase, while RSI also demonstrated large to very large associations with vertical stiffness and Vmax, respectively. Isoinertial eccentric force was largely correlated with Vmax, but only moderately correlated with vertical stiffness. Reactive and eccentric strength contribute to the ability to regulate leg spring stiffness at Vmax, and subsequently, the attainment of faster sprinting speeds in highly trained sprinters versus team sport athletes. However, stiffness regulation appears to be a task-specific neuromuscular skill, reinforcing the importance of specificity in the development of sprint performance.     

Effects of forward trunk lean on hamstring muscle kinematics during sprinting

This study aimed to investigate the effects of forward trunk lean on hamstring muscle kinematics during sprinting. Eight male sprinters performed maximal-effort sprints in two trunk positions: forward lean and upright. A three-dimensional musculoskeletal model was used to compute the musculotendon lengths and velocity of the biceps femoris long head, semitendinosus, and semimembranosus muscles during the sprinting gait cycle. The musculotendon lengths of all the three hamstring muscles at foot strike and toe-off were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. In addition, a positive peak musculotendon lengthening velocity was observed in the biceps femoris long head and semimembranosus muscles during the late stance phase, and musculotendon lengths at that instant were significantly greater during the forward trunk lean sprint than during the upright trunk sprint. The present study provides significant evidence that a potential for hamstring muscle strain injury involving forward trunk lean sprinting would exist during the stance phase. The results also indicate that the biceps femoris long head and semimembranosus muscles are stretched during forward trunk lean sprinting while contracting eccentrically in the late stance phase; thus, the elongation load on these muscles could be increased.     

Mechanics of the muscles crossing the hip joint during sprint running

Abstract

We aimed to demonstrate the changes over time in the lengths and forces of the muscles crossing the hip joint during overground sprinting and investigate the relationships between muscle lengths and muscle–tendon unit forces – particularly peak biceps femoris force. We obtained three-dimensional kinematics during 1 running cycle from 8 healthy sprinters sprinting at maximum speed. Muscle lengths and muscle–tendon unit forces were calculated for the iliacus, rectus femoris, gluteus maximus, and biceps femoris muscles of the target leg as well as the contralateral iliacus and rectus femoris. Our results showed that during sprinting, the muscles crossing the hip joint demonstrate a stretch-shortening cycle and 1 or 2 peak forces. The timing of peak biceps femoris force, expressed as a percentage of the running cycle (mean [SD], 80.5 [2.9]%), was synchronous with those of the maximum biceps femoris length (82.8 [1.9]%) and peak forces of the gluteus maximus (83.8 [9.1]%), iliacus (81.1 [5.2]%), and contralateral iliacus (78.5 [5.8]%) and also that of the peak pelvic anterior tilt. The force of the biceps femoris appeared to be influenced by the actions of the muscles crossing the hip joint as well as by the pelvic anterior tilt.     

Sprinting performance on the Woodway Curve 3.0TM is related to muscle architecture

Abstract

To determine if unilateral measures of muscle architecture in the rectus femoris (RF) and vastus lateralis (VL) were related to (and predictive of) sprinting speed and unilateral (and bilateral) force (FRC) and power (POW) during a 30 s maximal sprint on the Woodway Curve 3.0^TM non-motorized treadmill (TM). Twenty-eight healthy, physically active men (n = 14) and women (n = 14) (age = 22.9 ± 2.4 years; body mass = 77.1 ± 16.2 kg; height = 171.6 ± 11.2 cm; body-fa t = 19.4 ± 8.1%) completed one familiarization and one 30-s maximal sprint on the TM to obtain maximal sprinting speed, POW and FRC. Muscle thickness (MT), cross-sectional area (CSA) and echo intensity (ECHO) of the RF and VL in the dominant (DOM; determined by unilateral sprinting power) and non-dominant (ND) legs were measured via ultrasound. Pearson correlations indicated several significant (p < 0.05) relationships between sprinting performance [POW (peak, DOM and ND), FRC (peak, DOM, ND) and sprinting time] and muscle architecture. Stepwise regression indicated that POW_DOM was predictive of ipsilateral RF (MT and CSA) and VL (CSA and ECHO), while POW_ND was predictive of ipsilateral RF (MT and CSA) and VL (CSA); sprinting power/force asymmetry was not predictive of architecture asymmetry. Sprinting time was best predicted by peak power and peak force, though muscle quality (ECHO) and the bilateral percent difference in VL (CSA) were strong architectural predictors. Muscle architecture is related to (and predictive of) TM sprinting performance, while unilateral POW is predictive of ipsilateral architecture. However, the extent to which architecture and other factors (i.e. neuromuscular control and sprinting technique) affect TM performance remains unknown.     

Differences in hamstring activation characteristics between the acceleration and maximum-speed phases of sprinting

This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the acceleration sprint and maximum-speed sprint in 13 male sprinters during an overground sprinting. Differences in hamstring activation during each divided phases and in the hip and knee joint angles and torques at each time point of the sprinting gait cycle were determined between two sprints. During the early stance of the acceleration sprint, the hip extension torque was significantly greater than during the maximum-speed sprint, and the relative EMG activation of the BFlh muscle was significantly higher than that of the ST muscle. During the late stance and terminal mid-swing of maximum-speed sprint, the knee was more extended and a higher knee flexion moment was observed compared to the acceleration sprint, and the ST muscle showed higher activation than that of the BFlh. These results indicate that the functional demands of the medial and lateral hamstring muscles differ between two different sprint performances.     

青少年赛艇运动员专项力量训练的实践与思考

赛艇是周期性项目,人体肌肉力量是赛艇在水中行进时的动力源,只有增强运动员肌肉的快速力量,才能产生更快的速度。通过对青少年赛艇运动员专项力量训练3年的跟踪研究,得出一些实践心得,为广大教练员在青少年赛艇运动员力量训练与教学方面提供一定的借鉴。     

改革开放以来中国媒体体育宣传的发展及宣传观的演变

文章首先界定了媒体体育宣传的概念,然后围绕中国政治经济、体育事业以及媒体技术的发展这三个历史划分的维度,将改革开放以来媒体体育宣传分为兴起、发展、突破三个阶段;并以奥运宣传报道为例分析了媒体体育宣传实践的主要内容;最后探讨了改革开放以来中国媒体体育宣传观的演变,认为其宣传观是沿着宣传性、信息性到公共性的路径发展的。