Effects of cold water immersion on the recovery of physical performance and muscle damage following a one-off soccer match

The aim of this study was to assess the effects of a single session of cold or thermoneutral water immersion after a one-off match on muscular dysfunction and damage in soccer players. Twenty-male soccer players completed one match and were randomly divided into cryotherapy (10 min cold water immersion, 10°C, n = 10) and thermoneutral (10 min thermoneutral water immersion, 35°C, n = 10) groups. Muscle damage (creatine kinase, myoglobin), inflammation (C-reactive protein), neuromuscular function (jump and sprint abilities and maximal isometric quadriceps strength), and delayed-onset muscle soreness were evaluated before, within 30 min of the end, and 24 and 48 h after the match. After the match, the players in both groups showed increased plasma creatine kinase activity (30 min, 24 h, 48 h), myoglobin (30 min) and C-reactive protein (30 min, 24 h) concentrations. Peak jump ability and maximal strength were decreased and delayed-onset muscle soreness increased in both groups. However, differential alterations were observed between thermoneutral water and cold water immersion groups in creatine kinase (30 min, 24 h, 48 h), myoglobin (30 min), C-reactive protein (30 min, 24 h, 48 h), quadriceps strength (24 h), and quadriceps (24 h), calf (24 h) and adductor (30 min) delayed-onset muscle soreness. The results suggest that cold water immersion immediately after a one-off soccer match reduces muscle damage and discomfort, possibly contributing to a faster recovery of neuromuscular function.     

Effects of quality of opposition and match status on technical and tactical performances in elite volleyball

The aim of this study was to assess the effects of quality of opposition and match status on technical and tactical volleyball performances, as measured by block, attack, serve, and set actions related to the tasks, space, players, and efficacy of selected game actions. Twenty-five matches from the men's World Cup 2007 were notated and through cluster analysis were classified as "high" (HIGH), "intermediate" (INT) or "low" (LOW) quality. The difference between points scored and points allowed was used to define match status. Multinomial logistic regression identified an association of match status with: set direction (likelihood ratio test [LRT]?=?15.5, P?=?0.017) and block typology (LRT?=?9.6, P?=?0.047) in HIGH vs. HIGH matches; attack player (LRT?=?17.4, P?=?0.026) and block typology (LRT?=?9.2, P?=?0.010) in LOW vs. LOW matches; and serve type (LRT?=?17.4, P?=?0.002), block strategy (LRT?=?53.7, P?<0.001), and serve efficacy (LRT?=?26.0, P?=?0.001) in HIGH vs. LOW matches. Results suggest that volleyball teams took more risky decisions in unbalanced situations. They also carried less risk through technical and tactical decisions in balanced and moderate situations whether they had the advantage or not. Therefore, strategic behaviour was affected by the interaction of quality of opposition and match status, providing a better understanding of volleyball game performance and new insights for practice, competition, and research.     

Glenohumeral joint rotation range of motion in competitive swimmers

Much research has examined shoulder range of motion adaptations in overhead-unilateral athletes. Based on the void examining overhead-bilateral athletes, especially competitive swimmers, we examined shoulder external rotation, isolated internal rotation, composite internal rotation, and total arc of motion range of motion of competitive swimmers. The range of motion of registered competitive swimmers (n = 144, age = 12-61 years) was compared by limb (dominant, non-dominant), sex, and age group (youth, high school, college, masters). Significantly (P < 0.05) greater dominant external rotation was observed for both men and women high school and college swimmers, youth women swimmers, and men masters swimmers compared with the non-dominant limb. The isolated internal rotation (glenohumeral rotation), composite internal rotation (glenohumeral rotation plus scapulothoracic protraction), and total arc of motion (external rotation plus composite internal rotation) of the non-dominant limb was significantly greater than that of the dominant limb by sex and age group. Youth and high school swimmers demonstrated significantly greater composite internal rotation than college and masters swimmers. Youth swimmers displayed significantly greater total arc of motion than all other age groups. These data will aid in the interpretation of shoulder range of motion values in competitive swimmers during preseason screenings, injury evaluations and post-rehabilitation programmes, with the results suggesting that differences exist in bilateral external rotation, isolated internal rotation, composite internal rotation, and total arc of motion range of motion.     

Exercise cardiac power and the risk of heart failure in men: A population-based follow-up study

Background:Little is known about exercise cardiac power(ECP),defined as the ratio of directly measured maximal oxygen uptake with peak systolic blood pressure during exercise,on heart failure(HF)risk.We examined the association of ECP and the risk of HF.Methods:This was a population-based cohort study of 2351 men from eastern Finland.The average time to follow-up was 25 years.Participants participated at baseline in an exercise stress test.A total of 313 cases of HF occurred.Results:Men with low ECP(<9.84 mL/mmHg,the lowest quartile)had a 2.37-fold(95%confidence interval(95%CI):1.68-3.35,p<0.0001)hazards ratio of HF as compared with men with high ECP(>13.92 mL/mmHg,the highest quartile),after adjusting for age.Low ECP was associated with a 1.96-fold risk(95%CI:1.38-2.78,p<0.001)of HF after additional adjustment for conventional risk factors.After further adjustment for left ventricular hypertrophy,the results hardly changed(hazards ratio=1.87,95%CI:1.31-2.66,p<0.001).One SD increase in ECP(3.16 mL/mmHg)was associated with a decreased risk of HF by 28%(95%CI:17%-37%).Conclusion:ECP provides a noninvasive and easily available measure from cardiopulmonary exercise tests in predicting HF.However,ECP did not provide additional value over maximal oxygen uptake.     

Risk of bias and reporting practices in studies comparing VO2max responses to sprint interval vs. continuous training: A systematic review and meta-analysis

Background:It remains unclear whether studies comparing maximal oxygen uptake(VO_{2 max}) response to sprint interval training(SIT) vs.moderate-intensity continuous training(MICT) are associated with a high risk of bias and poor reporting quality.The purpose of this study was to evaluate the risk of bias and quality of reporting in studies comparing changes in VO_{2 max} between SIT and MICT.Methods:We conducted a comprehensive literature search of 4 major databases:AMED,CINAHL,E...     

Gender differences among sagittal plane knee kinematic and ground reaction force characteristics during a rapid sprint and cut maneuver

Women are more prone to anterior cruciate ligament (ACL) injury during cutting sports than men. The purpose of this study was to examine knee kinematic and ground reaction forces (GRF) differences between genders during cutting. Male and female athletes performed cutting trials while force platform and video data were recorded (180 Hz). Differences (p < . 05) were observed between groups for knee flexion at contact and GRF at maximum knee flexion. Women averaged 5.8 degrees less flexion at contact and 1.0 N. (kg x m x s(-1))(-1) greater GRF at maximum flexion. Knee range of motion and peak GRF variables were not significantly different, but women had greater values. Women exhibited technique characteristics believed to increase ACL injury risk, but men exhibiting similar characteristics were also observed and could also be at risk.     

“原谅我这一生不羁放纵爱自由” 行走在刃脊——致中国技术型登山的开拓者(?)一桦和他的搭档美国人JON OTTO

总有那样的人,是不甘于平庸的；也总有那样的人,永远不肯驻足。在远方,在路上,一直是他们生活的理想。在做这期户外运动的特别策划时,我们脑子里一直在萦绕着Beyond的那一首《海阔天空》：今天我寒夜里看雪飘过怀著冷却了的心窝飘远方风雨里追赶雾里分不清影踪天空海阔你与我可会变(谁没在变)多少次迎著冷眼与嘲笑从没有放弃过心中的理想一刹那恍惚若有所失的感觉不知不觉已变淡心里爱(谁明白我)原谅我这一生不羁放纵爱自由也会怕有一天会跌倒背弃了理想谁人都可以那会怕有一天只你共我仍然自由自我永远高唱我歌我们写了他们,写了热爱自由热爱行走的他们；我们也期待你,跃跃欲试身未动心却先行的你,加入到这样的行列。原谅我这一生不羁放纵爱自由’,我们的特别策划,献给所有这样的你,你们。     

Training and testing physical capacities for elite soccer players

Elite soccer players spend a substantial amount of time trying to improve physical capacities, including aerobic endurance and strength and the strength derivatives of speed and power. The average oxygen uptake for international soccer teams ranges from 55 to 68 ml.kg-1.min-1 and the half-squat maximal strength from 120 to 180 kg. These values are similar to those found in other team sports. Recently, it has been shown that the heart's stroke volume is the element in the oxygen chain that mainly limits aerobic endurance for athletes. These findings have given rise to more intensive training interventions to secure high stroke volumes, which, in turn, have proved positive in changing both maximal oxygen consumption and soccer performance in terms of distance covered, contacts with the ball and number of sprints in a game. The training employed has consisted of 4x4-min "intervals" running uphill at 90-95% of maximal heart rate interspersed with 3 min jogging at 70% of maximal heart rate to facilitate removal of lactate. Research has revealed that a soccer-specific training routine with the ball might be as effective as plain running. Strength training to produce neural adaptations has been effective in changing not only strength in terms of "one-repetition maximum", but also sprinting velocity and jumping height, in elite soccer players without any change in body mass. The same training has also improved running economy and thus aerobic endurance performance. The training regimen used for a European Champions League team was 4x4 repetitions of half-squats with the emphasis on maximal mobilization of force in the concentric action.     

20世纪的中国史学：对其背景和发展过程的评论

一在中国史学的现代化进程中 ,起作用的主要有三个因素。第一个因素是时势 ,因为时势变了 ,对过去历史的解释就得随之而改变。第二个因素是史学变革的手段 ,这可以从中国史学的自身传统中获得。第三个因素就是外来文化的影响 ,这种影响是通过近代西方史学以及其强劲的日本支脉而获得的。就史学领域本身来说 ,传统史学也是中国史学现代化的一个基础。更为重要的是 ,传统史学著作都是中国式的 ,故而更容易为人们所接受。梁启超在《中国历史研究法》一书中 ,就曾引用一系列中国古代批评旧思想的学者言论 ,借以说明他倡导的有悖于传统的历史观念…     

Profiles of social competence among low-income African American preschool children

Relations between children's personal attributes and peer play competence were investigated in a sample of 141 African American preschool children who participated in Head Start. Variable-oriented analyses confirmed that dispositions of temperament, emotion regulation, autonomy, and language were related to children's peer play competence in the classroom. Person-oriented analyses revealed distinctive profiles of personal attributes linked to adaptive preschool social functioning. A small group of resilient children whose profile was characterized by highly adaptable temperament, ability to approach new situations, and above average vocabulary development evidenced the greatest social competence with peers. Children who were disruptive with peers were equally divided between two profiles characterized by inattention and activity, but with differential performance on vocabulary tasks. A profile containing calm, reticent children was the group least likely to engage in disruptive peer play. Inspection of the six profiles revealed the within-group variability for this economically disadvantaged sample and illustrated the differential importance of temperament, regulation, and language constructs. Findings from the profile analyses and relations with peer competence inform the study of resilience in social development for urban African American children who participate in early intervention preschool programs.