黑龙江省摔跤运动员核心区域力量训练方法调研

通过专家访谈、文献资料、问卷调查、数理统计和实验等研究方法,调查黑龙江省摔跤队核心区域力量训练现状,并以之证实核心区域力量的重要性、有效性,提出针对性意见和建议,使摔跤运动员核心区域力量得以全面、有效的提高。     

Lower extremity injury in female basketball players is related to a large difference in peak eversion torque between barefoot and shod conditions

BackgroundThe majority of injuries reported in female basketball players are ankle sprains and mechanisms leading to injury have been debated. Investigations into muscular imbalances in barefoot versus shod conditions and their relationship with injury severity have not been performed. The purpose of this study was to investigate the effects of wearing athletic shoes on muscular strength and its relationship to lower extremity injuries, specifically female basketball players due to the high incidence of ankle injuries in this population.MethodsDuring pre-season, 11 female collegiate basketball players underwent inversion and eversion muscle strength testing using an isokinetic dynamometer in both a barefoot and shod conditions. The difference between conditions was calculated for inversion and eversion peak torque, time to peak torque as well as eversion-to-inversion peak torque percent strength ratio for both conditions. Lower extremity injuries were documented and ranked in severity. The ranked difference between barefoot and shod conditions for peak torque and time to peak torque as well as percent strength ratio was correlated with injury ranking using a Spearman rho correlation (ρ) with an α level of 0.05.ResultsThe ranked differences in barefoot and shod for peak eversion and inversion torque at 120°/s were correlated with their injury ranking. Ranking of the athletes based on the severity of injuries that were sustained during the season was found to have a strong, positive relationship with the difference in peak eversion torque between barefoot and shod (ρ = 0.78; p = 0.02).ConclusionIt is possible that a large discrepancy between strength in barefoot and shod conditions can predispose an athlete to injury. Narrowing the difference in peak eversion torque between barefoot and shod could decrease propensity to injury. Future work should investigate the effect of restoration of muscular strength during barefoot and shod exercise on injury rates.     

排球运动员的体能特征与训练探析

本文着重对排球运动中的体能特征与训练进行了探讨,从体能训练的概念、生物学基础、频度和节奏、训练注意事项等方面作出分析,提出体能训练是现代排球比赛竞争的基础条件之一,体能训练不能等同于身体素质训练,体能训练应有自己的生物学基础。     

中高水灰比混凝土强度与工作性能的研究

混凝土依赖水灰比(W/B)获得工作性能,中高水灰比混凝土之所以有较高的强度,是因为使用了超硫酸盐水泥。超硫水泥在水化期间能够形成大量的钙矾石晶体,从而抵抗了部分混凝土的收缩,因此中高水灰比混凝土在工作性得到保证的同时,也具有较高的强度。本研究内容是:(1)超硫水泥在不同配比下的标准稠度需水量、流动度、凝结时间。(2)使用不同配比超硫水泥的混凝土的坍落度、扩展度、含气量及抗压抗折强度实验。通过实验找出强度和工作性能良好的混凝土配合比。     

第42届IMO第二题的证明与加强

本文给出了第42届IMO第二题的一个简捷证明与一个加强,丰富了权方和不等式的使用功能.     

当代大学生心理弹性调查分析

采用Connor-Davidson心理弹性量表中文版(CD-RISC)对532名大学生的心理弹性状况进行调查分析。结果表明:大学生心理弹性总量表及坚韧维度呈现出显著的性别差异,男生得分显著高于女生,而力量和乐观两个维度不存在性别差异;在心理弹性总量表及坚韧、力量、乐观3个维度上,不同年级的大学生得分差异有显著性;大学生心理弹性不存在居住地、学科性质和是否独生子女等的显著性差异。     

Kinanthropometric and physiological characteristics of outrigger canoe paddlers

We describe the physiological characteristics of amateur outrigger canoe paddlers. Twenty-one paddlers (13 males, 8 females) were evaluated for body stature, aerobic power, muscular strength and endurance, peak paddle force, flexibility and 250 m sprint paddle performance at the end of the outrigging season. The mean variables ( - s) for the males were: age 27 - 9 years, height 175 - 5 cm, body mass 80 - 5 kg, arm span 178 - 7 cm, sitting height 100 - 2 cm, aerobic power 3.0 - 0.4 l·min-1, maximum bench press strength 85 - 19 kg, right peak paddle force 382 - 66 N and left peak paddle force 369 - 69 N. For the females, these were: age 26 - 6 years, height 168 - 5 cm, body mass 70 - 8 kg, arm span 170 - 5 cm, sitting height 97 - 3 cm, aerobic power 2.3 - 0.5 l· min-1, maximum bench press strength 47 - 10 kg, right peak paddle force 252 - 63 N and left peak paddle force 257 - 60 N. Analysis of variance revealed diff erences (P ? 0.05) between the dominant and non-dominant sides of the body for peak paddle force, isokinetic internal and external rotation, and flexion and extension torque of the shoulder joint. The outrigger canoe paddlers were generally within the range of scores found to describe participants of other water craft sports. Outrigger canoeists should be concerned with the muscular strength imbalances associated with paddling technique.     

PART III: HUMAN PERFORMANCE

There is limited information on the anthropometry, strength, endurance and flexibility of female rock climbers. The aim of this study was to compare these characteristics in three groups of females: Group 1 comprised 10 elite climbers aged 31.3 ± 5.0 years (mean ± s ) who had led to a standard of ‘hard very severe’; Group 2 consisted of 10 recreational climbers aged 24.1 ± 4.0 years who had led to a standard of ‘;severe’; and Group 3 comprised 10 physically active individuals aged 28.5 ± 5.0 years who had not previously rock-climbed. The tests included finger strength (grip strength, finger strength measured on climbing-specific apparatus), flexibility, bent arm hang and pull-ups. Regression procedures (analysis of covariance) were used to examine the influence of body mass, leg length, height and age. For finger strength, the elite climbers recorded significantly higher values ( P < 0.05) than the recreational climbers and non-climbers (four fingers, right hand: elite 321 ± 18 N, recreational 251 ± 14 N, non-climbers 256 ± 15 N; four fingers, left hand: elite 307 ± 14 N, recreational 248 ± 12 N, non-climbers 243 ± 11 N). For grip strength of the right hand, the elite climbers recorded significantly higher values than the recreational climbers only (elite 338 ± 12 N, recreational 289 ± 10 N, non-climbers 307 ± 11 N). The results suggest that elite climbers have greater finger strength than recreational climbers and non-climbers.     

Physiological requirements of cricket

Despite its long history and global appeal, relatively little is known about the physiological and other requirements of cricket. It has been suggested that the physiological demands of cricket are relatively mild, except in fast bowlers during prolonged bowling spells in warm conditions. However, the physiological demands of cricket may be underestimated because of the intermittent nature of the activity and the generally inadequate understanding of the physiological demands of intermittent activity. Here, we review published studies of the physiology of cricket. We propose that no current model used to analyse the nature of exercise fatigue (i.e. the cardiovascular–anaerobic model, the energy supply–energy depletion model, the muscle power–muscle recruitment model) can adequately explain the fatigue experienced during cricket. A study of players in the South African national cricket team competing in the 1999 Cricket World Cup revealed that, in a variety of measures of explosive ('anaerobic') power and aerobic endurance capacity, they were as 'fit' as South African national rugby players competing in the 1999 Rugby World Cup. Yet, outwardly, the physiological demands of rugby would seem to be far greater than those of cricket. This poses the question: 'Why are these international cricketers so fit if the physiological demands of cricket are apparently so mild?' One possibility is that this specific group of athletes are unusually proficient in a variety of sports; many achieved high standards of performance in other sports, including rugby, before choosing to specialize in cricket. Hence their apparently high fitness may simply reflect a superior genetic physical endowment, necessary to achieve success in modern international sports, including cricket. Alternatively, it could be hypothesized that superior power and endurance fitness may be required to cope with the repeated eccentric muscle contractions required in turning and in bowling and which may account for fatigue and risk of injury in cricket. If this is the case, the fitness of cricketers may be increased and their risk of injury reduced by more specific eccentric exercise training programmes.