Effects of Training on the Estimation of Muscular Moment in Submaximal Exercise

Abstract

The purpose of this study was to observe the effects of a submaximal isometric training program on estimation capacity at 25, 50, and 75% of maximal contraction in isometric action and at two angular velocities. The second purpose was to study the variability of isometric action. To achieve these purposes, participants carried out an isokinetic extension movement of the dominant lower limb during six test sessions and nine training sessions. Following the training program, estimation capacity in the different actions did not improve. However, an improvement in performance was observed with a reduction in the variability of submaximal isometric actions. The proprioceptors activated in isometric action seemed to adapt to the training program itself, which would promote better adaptation by a greater solicitation of internal feedback.     

Gender Differences in Strength

The purpose of this study was to examine gender differences in upper and lower body strength as a function of lean body weight and the distribution of muscle and subcutaneous fat in the upper and lower limbs. The subjects were 103 physically active men (n = 48) and women (n = 55). The peak torques produced during shoulder flexion (SF) and knee extension (KE) were used as measures of upper body and lower body strength, respectively. Flexed arm girth, thigh girth, triceps skinfold, and thigh skinfold were used to estimate the distribution of muscle and subcutaneous fat in the limbs. Results of the MANOVA revealed that the overall strength of men was significantly greater than that of women. Results of MANCOVA indicated that the SF and KE strength of women and men did not differ significantly when differences in lean body weight, arm girth, thigh girth, triceps skinfold and thigh skinfold were statistically controlled. High levels of SF and KE strength were associated with a high lean body weight and a large arm girth. Results of the multiple regression analysis indicated that for men a substantial portion of the variance in both SF and KE strength was explained by lean body weight alone; whereas strength variations in women were explained more adequately by including limb variables along with lean body weight. Within the limitations of this study, it was concluded that gender differences in upper and lower body strength are a function of differences in lean body weight and the distribution of muscle and subcutaneous fat in the body segments. Upper body strength is relatively more important than lower body strength in characterizing the gender difference in strength.     

The Relationships Among Isokinetic Endurance,Initial Strength Level,and Fiber Type

Abstract

Knee extension isokinetic peak torque was assessed at angular velocities of 0, 30, 180, and 240[ddot]/sec, and isokinetic endurance was assessed by 50 consecutive contractions at 180[ddot]/sec in eight college age men. Also, muscle fiber type of the vastus lateralis was determined and related to isokinetic strength and fatigability. To determine the influence of initial strength on isokinetic endurance the 50 serial isokinetic contractions were assessed after subjects performed two bicycle exercise regimens designed to affect initial strength levels. Neither isokinetic peak torques (made relative to MVC or per Kg of body weight) nor the amount of strength loss over the 50 contractions correlated with fiber type. The peak torques at 180[ddot]/sec at the start of the 50 contractions differed over the three conditions (unfatigued and after the two bicycle exercise regimens), however, the amount of of strength loss over the 50 trials was similar for the three conditions. Also, the patterns of the three isokinetic fatigue curves were remarkably similar. Thus, the initial strength level across the treatments did not affect the rate of fatigue. However, when the treatment conditions were examined separately, the amount of strength loss over the 50 trials correlated significantly with initial strength. Thus, factors other than, or in addition to, fiber type and initial strength level must influence the rate of isokinetic fatigue.     

我国优秀女子速滑运动员下肢肌群力学特性的分析

为了找出使用新冰刀后蹬冰时下肢三关节肌群的生物力学特性,首次利用数值计算中的牛顿插值法,将等动测试获得的动力学数据和三维立体解析获得的运动学数据结合,绘出两名优秀女子速滑运动员实际蹬冰时肌群力矩的变化曲线,并分析肌力变化特点,找出两人做功明显不足的原因,为指导训练和提高运动成绩提供定量依据。     

等动测力及康复训练系统在运动员膝关节损伤后力量训练中的应用

研究利用等动测力及康复系统对膝关节损伤的女运动员进行等速向心训练。经过约8周的训练,患膝屈伸肌群的峰值力矩在不同测试速度下均有显著提高,但伸肌峰值力矩提高较屈肌快。此次研究表明等速向心训练对膝关节损伤后的肌肉功能恢复有一定的促进作用。     

Body Composition and Anthropometric Correlates of Isokinetic Leg Extension Strength of Young Adult Males

Abstract

The present study examined the relative importance of body size and composition as determinants of individual differences in isokinetic leg extensor strength in young adult males performing at slow, moderate, and fast speeds. The subjects were 31 males between the ages of 19 and 29 years, who were not participating in weight training programs. Low to moderate correlations were found between isokinetic strength and body size or body composition measurements. At each speed, similar proportions of the variance in peak torque values were accounted for by lean body weight (23-30%) and thigh volume (20-37%). However, body weight, often suggested as the best reference standard for equalizing strength scores, also accounted for only 13-24% of the variance in peak torque values at each of the speeds tested. The moderate correlations reported in this study do not support the use of body size and composition measurements as a means of adjusting strength values.     

Does a land-based compensatory strength-training programme influences the rotator cuff balance of young competitive swimmers?

Abstract

During the repeated execution of the swimming strokes, the shoulder adductor and internal rotator muscles have a tendency to become proportionally stronger when compared to their antagonist group. This can lead to muscle imbalances. The aim of this study was to examine the effects of a compensatory training programme on the strength and balance of shoulder rotator muscles in young swimmers. A randomized controlled trial design was used. Forty male swimmers took part in the study and were randomly divided into two groups: an experimental group (n?=?20) and a training group (n?=?20). A control group (n?=?16) of young sedentary male students was also evaluated. The experimental group subjects participated in a 16-week shoulder-strength programme with Thera-Band^® elastic bands; the training group was restricted to aquatic training. Peak torque of shoulder internal rotator and external rotator (ER) was measured at baseline and after 16 weeks. Concentric action at 1.04?rad?s^?1 (3 reps) and 3.14?rad?s^?1 (20 reps) was measured using an isokinetic dynamometer. The strength-training programme led to an improvement of the ER strength and shoulder rotator balance in the experimental group (data from both shoulders at 1.04?rad?s^?1). Moreover, concentric action at 3.14?rad?s^?1 presented significant differences only for the dominant shoulder. Findings suggest that the prescribed shoulder-strengthening exercises could be a useful training option for young competitive swimmers. They can produce an increase in absolute strength values and greater muscle balance in shoulder rotators.     

功能性力量训练对男子自由式摔跤运动员膝关节等速肌力影响的研究

目的:分析功能性力量训练对男子自由式摔跤运动员膝关节等速肌力的影响。对象与方法:运用实验法,以16名广东省男子自由式摔跤队运动员为研究对象,随机分为对照组和实验组并将其分别进行为期8周的训练干预,其中对照组进行常规力量训练,实验组进行功能性力量训练,实验前后分别测试所有运动员的膝关节等速肌力,选取峰值力矩(PT)、异侧同名肌比值(PTR)和同侧屈伸肌比值(H/Q)指标比较分析功能性训练在提高男子自由式摔跤运动员下肢力量素质的影响。结果:实验组运动员经过功能性力量训练,等速肌力测试在角速度60°/s和240°/s状态下,下肢双侧屈肌PT和伸肌PT较实验前均有非常显著性提高(P<0.01),屈伸肌PTR及左右侧H/Q也均有非常显著性提高(P<0.01)。对照组运动员经过传统力量训练,等速肌力测试在角速度60°/s和240°/s状态下,下肢双侧屈肌和伸肌PT值较实验前均有显著性提高(P<0.01),但是左右侧H/Q及屈伸肌PTR均无显著性变化(P>0.05)。实验后在角速度60°/s状态下,实验组运动员膝关节两侧伸肌PT与对照组相比均无显著性差异(P>0.05),但是两侧屈肌PT值均显著高于对照组(P<0.05);在角速度240°/s状态下实验组左侧伸肌PT值显著高于对照组(P<0.05),右侧伸肌PT值虽高于对照组,但是差异不显著(P>0.05),左右侧的屈肌PT值均非常显著高于对照组(P<0.01);实验组运动员的屈伸肌PTR及左右侧的H/Q均非常显著高于对照组(P<0.01)。结论:功能性训练可以显著提高男子自由式摔跤运动员的下肢肌肉最大力量和快速力量素质,在最大力量训练效果方面与传统力量训练相比差异不大,但是在快速力量方面提高效果要更好;功能性力量训练能够有效提高自由式摔跤运动员的异侧同名肌比值和屈伸肌比值,对改善运动员两侧肌肉力量不对称和同侧屈伸肌力量不对称方面效果也比传统力量训练效果更好,对运动员膝关节肌群肌力的平衡有着重要作用。     

等动力量训练的力量增长规律

目的：探索增长的规律,为科学制定体育训练和康复训练提供科学依据。方法：分为实验组和对照组,训练频率采用1天1次、2天1次,3天1次三种,对35名浙江大学正常健康男女大学生分组进行为期四周的单腿等动肌力训练,同对照组相比较,研究单侧腿伸肌在时间维度上的力量增长规律。结果：三种频率之间没有显著差异,但各组被试的膝关节髌骨内侧肌拉伤率存在显著差异,3天一次组没有出现膝关节髌骨内侧肌拉伤。结论：等动力量训练能够在短期内显著提高肌肉力量,3天1次可能是比较理想的训练频率。     

优秀投掷运动员核心力量等速肌力测试研究

目的:分析浙江师范大学投掷训练队优秀运动员腰背肌的生物力学特征,探讨投掷运动员的成绩与腰背屈伸肌群力量的关系,为投掷训练和易受伤部位的预防提供理论依据。方法:利用德国Isomed2000等速肌力测试系统进行核心力量等速肌力测试,测试严格按照Isomed2000等速测试系统使用手册的要求进行操作。结果:优秀投掷运动员腰背屈伸肌群等速向心收缩峰力矩随测试速度(30°/s~180°/s)的增加大体呈递减趋势,且随着角速度的增大,优秀投掷运动员的腰背屈伸肌群等速向心收缩峰力矩下降幅度(斜率K:伸-0.884小于屈-0.655)比普通人(K:伸-0.275小于屈-0.035)小,且优秀投掷运动员伸肌最大峰力矩的下降幅度要比屈肌小;在角速度为30°/s到120°/s时,最大功率随着给定角速度的增大而增大,在180°/s时又有所减小;腰背屈伸肌群峰力矩的角度在30°/s到180°/s时伸肌55.5°~58°大于屈肌的54.5°~56.25°,随着角速度的增大,大体呈上升趋势,在30°/s时峰力矩角度最小。     

简易力量测试法和等速肌力测试相关性研究

目的:探讨体质监测中握力、下肢蹬踏爆发力作为力量素质的简易测试法能否反映人体的力量素质。方法:随机抽取311例上海市普通市民,进行握力,下肢蹬踏爆发力,肘、膝关节运动速度为60°/s的等速向心力量测试。对握力与肘关节等速向心力量,下肢蹬踏爆发力与膝关节等速向心力量进行相关性统计分析。结果:握力与肘关节屈肌峰力矩正相关(r=0.815),与肘关节屈肌相对峰力矩正相关(r=0.712);下肢蹬踏爆发力与膝关节屈肌峰力矩正相关(r=0.764),与伸肌峰力矩正相关(r=0.766);结论:握力、下肢蹬踏爆发力可以作为人体力量素质的简易测试方法并可应用于体质监测工作中。     

等速力量测试在监控我国优秀女足运动员力量训练中的应用

利用CYBEX-NormT等速测试系统对我国46名优秀女子足球运动员膝关节屈伸肌群进行等速向心收缩测试与分析,结果提示:(1)提高我国女子足球运动员伸肌的最大力量和快速力量是提高运动能力的关键;(2)为防止腘绳肌的拉伤,应适当提高女足队员的膝关节屈肌的力量;(3)我国女子足球运动员膝关节屈伸肌比率不均衡是导致膝关节损伤的主要原因,力量训练中应加强屈、伸肌力量,尤其是伸肌的力量,以改善屈伸比率的不平衡,防止损伤的发生;(4)我国女子足球运动员存在两腿屈、伸肌力量不平衡现象,在力量训练中,应加强对弱势腿的力量训练,以保证两腿的肌力平衡,防止损伤的发生。     

等速测力评价柔道运动员伤后力量特征及应用

1研究目的柔道属创伤发生率较高的接触性运动项目,本研究从肌力平衡角度探索柔道运动员伤后的力量特征,分析关联运动损伤的敏感评价指标,将有助于降低柔道运动员的损伤发生率,并为开展相应的康复性体能训练提供指导依据。     

综合力量训练对中国女子篮球运动员腰、膝、踝等速力量的影响

目的:了解在常规力量训练基础附加核心力量训练及振动训练方法对国家女子篮球队18名运动员腰背、膝关节、踝关节等速肌力的影响。方法:采用Pneu VIBE振动训练台对国家女子篮球运动员进行振动刺激力量训练,振动频率为25～40 Hz,同时进行核心区肌力训练。经过12周系统的力量训练,应用IsoMed 2000等速测试训练仪器对女子篮球运动员腰腹、膝、踝关节屈伸肌群进行等速力量测试分析。结果:经过12周综合力量训练,女子篮球运动员腰背等速肌力明显上升,屈肌峰力矩(PT)增加了14.35%,背伸肌力量增加了15.65%,差异具有显著性。而下肢力量膝关节峰力矩、屈伸肌峰力矩比率(H/Q)无显著变化。踝关节研究发现,左踝背屈峰力矩训练后稍有减弱,跖屈肌峰力矩以及跖屈/背屈比无显著变化。结论:在常规力量训练中增加先进的核心区训练可有效增加女子篮球运动员腰腹肌力,而振动训练以提高踝、膝关节肌力的方法的有效性需要进一步研究。     

Yearly Changes in the Body Composition and Muscular Strength of High School Wrestlers

Abstract

The purpose of this investigation was to determine the yearly changes in body composition as well as absolute and relative isokinetic forearm flexion and extension strength of high school wrestlers. Evaluations of body composition (underwater weighing) were performed on 27 high school wrestlers prior to three consecutive seasons. In addition, isokinetic forearm flexion and extension strength values at 180°/s (Cybex II) were available for 20 of the subjects. The mean ages at the times of laboratory testing were 15.5 (± .5), 16.5 (± .5), and 17.5 (± .5) years. Repeated measures ANOVA or ANCOVA with Tukey post-hoc comparisons were used to locate significant (p<.05) differences across age for height, body weight, relative fat, body density, fat weight, fat-free weight, absolute muscular strength, and muscular strength covaried for body weight and fat-free weight. There were yearly increases in all variables except fat weight, forearm flexion covaried for fat-free weight and forearm extension covaried for fat-free weight. The results of this study indicated that the improved wrestling performance and the increase in weight classification which normally occurs during high school are, in part, a function of yearly changes in body composition and muscular strength.