An electromyographic comparison of a modified version of the plank with a long lever and posterior tilt versus the traditional plank exercise

The purpose of the study was to compare core muscle activation of the tradition prone plank with a modified version performed with a long-lever and posterior-tilt using surface electromyography. To further determine if a specific component of this modified plank was more effective than the other in enhancing muscle activity, the plank with a long lever and the plank with a posterior pelvic tilt were studied individually. Nineteen participants performed all four variations of the plank for 30 seconds in a randomized order with 5-minute rest between exercise bouts. Compared to the traditional prone plank, the long-lever posterior-tilt plank displayed a significantly increased activation of the upper rectus abdominis (p < 0.001), lower abdominal stabilizers (p < 0.001), and external oblique (p < 0.001). The long-lever plank showed significantly greater activity compared to the traditional plank in the upper rectus abdominis (p = 0.015) and lower abdominal stabilizers (p < 0.001), while the posterior tilt plank elicited greater activity in the external oblique (p = 0.028). In conclusion, the long-lever posterior-tilt plank significantly increases muscle activation compared to the traditional prone plank. The long-lever component tends to contribute more to these differences than the posterior-tilt component.     

男子标枪运动员肩、肘、髋关节屈伸肌力的等速测试研究

采用澳大利亚KEYLINK公司生产的等速肌力测试系统,对20名二级以上水平的男子标枪运动员肩、肘、髋关节肌肉力量进行等速向心测试,结果表明屈伸肌由60°/s到120./s或180°/s时,肩、肘屈伸肌和髋伸肌峰力矩、相对峰力矩减小,髋屈肌峰力矩、屈伸肌相对峰力矩增大;肩、髋屈伸比增大,肘屈伸比减小.     

浅析健身气功易筋经功法特点对呼吸肌的作用

健身气功易筋经的特点是变易筋骨,呼吸自然,精神内含而放松.而呼吸自然和精神内含促成了身体放松,利于身形不僵不硬地"拔骨""伸筋",使肌肉以不同形式的收缩工作,伸拉关节、肌肉、肌腱、韧带等组织,并刺激肌肉等软组织.又由于身肢反复的伸、收、展、合、转,使人体胸廓充分的开合,从而刺激呼吸肌群,增强呼吸肌肌力、呼吸肌耐力、呼吸肌的伸缩性,提高呼吸肌的储备力.     

谈肢体肌肉技能反馈在田径技术训练中的作用

着重从理论上阐述田径技术教学训练中肢体肌肉技能反馈对促进运动技能形成的重要作用，指出为了提高学生对技术动作的掌握能力，教学训练中必需重视和传授技能反馈的理论知识。     

低氧、离心力竭运动对骨骼肌自由基代谢的影响

研究目的是探讨低氧和离心力竭运动对骨骼肌自由基代谢的影响。结果显示:离心运动后即刻骨骼肌MDA生成大量增加,运动后1天达峰值,脂质过氧化作用破坏了细胞膜,骨骼肌损伤进一步加重。安静状态下,随着低氧时间的延长,骨骼肌SOD活性明显下降。且大鼠力竭运动后低氧的前2天,骨骼肌中SOD活性的升高幅度不及常氧组。表明组织缺氧会抑制骨骼肌自由基清除剂的生成。     

运动对心肌热休克蛋白的影响

运用文献资料法，对热休克蛋白的重要生物学功能以及运动对心肌热休克蛋白的影响进行综述。     

确定下肢肌肉附着点空间坐标的研究及其应用

采用近景摄影测量的先进技术,对人体(尸体)下肢肌肉的起止点进行量测;运用计算机进行编程解析,求得国人下肢肌肉附着点的三维坐标。建立下肢4个运动环节的独立坐标系;运用刚体方位广义坐标描述下肢环节运动;提供肌肉机能评定相关的定量参数资料。建立起止点坐标与有关的人体测量参数间的回归方程,为活体下肢肌肉起止点的推算提供依据。     

核心力量训练对网球运动影响的研究综述

近年来,核心力量训练在体能训练中引起了很多人的关注,但是关于网球运动员核心力量训练的研究在国内学术界仍是一个新的研究课题.文章采用综述的形式参阅了大量的文献,对核心肌肉及核心力量的概念进行探究,通过分析网球技术动作中肌肉的利用,阐明了核心力量对网球运动的重要性,从而帮助人们更好地认识核心力量训练.     

Functional differences in the activity of the hamstring muscles with increasing running speed

Abstract

In this study, we examined hamstring muscle activation at different running speeds to help better understand the functional characteristics of each hamstring muscle. Eight healthy male track and field athletes (20.1 ± 1.1 years) performed treadmill running at 50%, 75%, 85%, and 95% of their maximum velocity. Lower extremity kinematics of the hip and knee joint were calculated. The surface electromyographic activities of the biceps femoris and semitendinosus muscles were also recorded. Increasing the running speed from 85% to 95% significantly increased the activation of the hamstring muscles during the late swing phase, while lower extremity kinematics did not change significantly. During the middle swing phase, the activity of the semitendinosus muscle was significantly greater than that of the biceps femoris muscle at 75%, 85%, and 95% of running speed. Statistically significant differences in peak activation time were observed between the biceps femoris and semitendinosus during 95%max running (P < 0.05 for stance phase, P < 0.01 for late swing phase). Significant differences in the activation patterns between the biceps femoris and semitendinosus muscles were observed as running speed was increased, indicating that complex neuromuscular coordination patterns occurred during the running cycle at near maximum sprinting speeds.     

Fingertip force and electromyography of finger flexor muscles during a prolonged intermittent exercise in elite climbers and sedentary individuals

Abstract

The aim of this study was to characterize forearm muscle fatigue identified by the decrease in electromyogram median frequency and/or fingertip force during intermittent exercise. Nine elite climbers (international competitive level, USA 5.14a on sight) and ten non-climbers were instructed to maintain a fingertip force of 80% of their maximal voluntary contraction force on a dynamometer mimicking a rock climbing grip during a 5 s effort/5 s rest cycle for 36 repetitions (i.e. 6 min of exercise). Elite climbers lasted twice as long as non-climbers (climbers: 3 min; non-climbers: 1 min 30 s) before the force could no longer be maintained (i.e. the failure point). After this moment, fingertip force decreased and stabilized until the end of the exercise around 50% maximum voluntary contraction force in non-climbers and 63% in elite climbers. Electromyogram median frequency showed a greater decrease in non-climbers than in elite climbers before the failure point. No change in median frequency was observed after the failure point in elite climbers or in non-climbers. These results confirm that elite climbers are better adapted than non-climbers for performing the intermittent fingertip effort before the failure point. After this point, the better fingertip force of elite climbers suggests different forearm muscle properties, while the electromyography results do not provide any indication about the fatigue process.