Sprint kayaking and canoeing performance prediction based on the relationship between maturity status,anthropometry and physical fitness in young elite paddlers

This study aimed to identify the maturity-related differences and its influence on the physical fitness, morphological and performance characteristics of young elite paddlers. In total, 89 kayakers and 82 canoeists, aged 13.69 ± 0.57 years (mean ± s), were allocated in three groups depending on their age relative to the age at peak height velocity (pre-APHV, circum-APHV and post-APHV) and discipline (kayak and canoe). Nine anthropometric variables, a battery of four physical fitness tests (overhead medicine ball throw, countermovement jump, sit-and-reach test and 20 m multistage shuttle run test) and three specific performance tests (1000, 500 and 200 m) were assessed. Both disciplines presented significant maturity-based differences in all anthropometric parameters (except for fat and muscle mass percentage), overhead medicine ball throw and all performance times (pre > circum > post; P < 0.05). Negative and significant correlations (P < 0.01) were detected between performance times, chronological age and anthropometry (body mass, height, sitting height and maturity status), overhead medicine ball throw and sit and reach for all distances. These findings confirm the importance of maturity status in sprint kayaking and canoeing since the more mature paddlers were also those who revealed largest body size, physical fitness level and best paddling performance. Additionally, the most important variables predicting performance times in kayaking and canoeing were maturity status and chronological age, respectively.     

Association of different types of playing surfaces with bone mass in growing girls

The aim of this cross-sectional study was to compare bone mass in young female athletes playing ball games on different types of playing surfaces. About 120 girls, 9–13 years of age (10.6 ± 1.5 years old Tanner I–III) were recruited and divided into prepubertal and pubertal groups. The sample represented 3 groups of athletes: soccer (N = 40), basketball (N = 40), and handball (N = 40); and 6 different playing surfaces (soccer – ground, soccer – artificial turf, basketball – synthetic, basketball – parquet, handball – synthetic, and handball – smooth concrete). Total and regional body composition (bone mass, fat mass, and lean mass) were measured by dual-energy X-ray absorptiometry (DXA). The mechanical properties of the surfaces (force reduction, vertical deformation, and energy return) were measured with the Advanced Artificial Athlete (Triple A) method. The degree of sexual development was determined using Tanner test. The pubertal group showed that soccer players on the ground, basketball players on synthetic, and handball players on smooth concrete had higher values of bone mineral content (BMC) and bone mineral density (BMD) (P < 0.05) than the soccer players on the artificial turf, basketball players on parquet, and handball players on synthetic. In conclusion, a hard playing surface, with less vertical deformation and force reduction, and greater energy return, is associated with higher levels of BMD and BMC in growing girls, regardless of the sport they practice.     

Circadian rhythm effect on physical tennis performance in trained male players

To determine the effect of circadian rhythm on neuromuscular responses and kinematics related to physical tennis performance, after a standardised warm-up, 13 highly competitive male tennis players were tested twice for serve velocity/accuracy (SVA), countermovement vertical jump (CMJ), isometric handgrip strength (IS), agility T-test (AGIL) and a 10-m sprint (10-m RUN). In a randomised, counter-balance order, tennis players underwent the test battery twice, either in the morning (i.e., AM; 9:00 h) and in the afternoon (i.e., PM; 16:30 h). Paired t-tests were used to analyse differences due to time-of-day in performance variables. Comparison of morning versus afternoon testing revealed that SVA (168.5 ± 6.5 vs. 175.2 ± 6.1 km · h^?1; P = 0.003; effect size [ES] = 1.07), CMJ (32.2 ± 0.9 vs. 33.7 ± 1.1 cm; P = 0.018; ES = 1.46), AGIL (10.14 ± 0.1 vs. 9.91 ± 0.2 s; P = 0.007; ES = 1.23) and 10-m RUN time (1.74 ± 0.1 vs. 1.69 ± 0.1 s; P = 0.021; ES = 0.67) were significantly blunted during the morning testing. However, IS was not affected by time-of-day (P = 0.891). Thus, tennis performance may be reduced when competing in the morning in comparison to early evening. Therefore, coaches and tennis players should focus on schedule the SVA, power, speed and agility training sessions in the afternoon.     

Emotions’ management within the Real Madrid football club business model

Recent changes in the sports industry – derived from increasing financial pressures – have led to the update of existing business models. Particularly in football, the dominant clubs develop new business models based on the spectators’ commitment to the sport. Packed stadiums attract more people who consume both the matches and the many other associated goods and services. In an experience economy, the lever is the tapping of their emotions by an increasingly sophisticated value proposal. Groups of passionate supporters lead the way to the establishment of communities with a common interest in the club. Following a qualitative methodology (interviews and other texts’ analysis) our study of the Real Madrid Football Club (RM) business model suggests that one of the biggest football clubs in the world is creating a business model based on the emotions of its supporters. This finding could be useful for other clubs in many different countries.     

The condition of high-performance athletes in France since the Mazeaud Law of 1975

High-level athletes are accorded deferential treatment by the French state. They enjoy the status of ‘high-performance athletes', which entitles them to assistance from the state and a set of special provisions. This paper provides an overview of the political circumstances in which this status was originated and developed, from its initial recognition under the 1975 Sports Law to the paradoxical social effects that this state policy has had on its beneficiaries: the athletes themselves. The first part of the paper is based largely on a search of parliamentary archives relating to the adoption of this law, known as the Mazeaud law, while the second part is based on a survey and interviews conducted with a number of French athletes who were selected for the 1972 and 1992 Olympic Games in Munich and Barcelona respectively. In addressing these two key phases in the recognition of athlete status, its political development and its subsequent reception, the article illustrates the changes in both status and condition of high-performance athlete, based on very different time scales and inspired by fairly different expectations. Given that the present system aims to improve the position of athletes in terms of their post-competitive lives, the long-term benefit of representing France under these circumstances remains questionable.     

‘Governmentality’ in the origins of European female PE and sport: the Spanish case study (1883–1936)

The purpose of the paper is twofold: (1) to contribute to the analysis of the origins of modern European female PE and sports from a power perspective, inspired by Foucault's work; and (2) to present a detailed analysis of female PE and sport in Spain (1883–1936) as a specific European case study. It is argued that these physical activities could be conceived in the Spanish case as part of a specific kind of ‘governmentality’ with a dual nature. On the one hand they represented disciplinary ‘technologies of power’ over the female body. Selected physical activities—dictated mainly from the hygienic-moral position of the Regeneracionistas (‘Regenerationists’)—were exerted as a kind of ‘bio-power’ for the control of the female population. On the other hand, such kind of activities (especially sports) represented certain ‘technologies of the self’ for middle and upper class women. Through participation in sports, women gained a more active and public role in the Spanish society of the era, obtaining some degree of autonomy in self-governance over their bodies and their lives.     

Automatic measurement of key ski jumping phases and temporal events with a wearable system

We propose a new method, based on inertial sensors, to automatically measure at high frequency the durations of the main phases of ski jumping (i.e. take-off release, take-off, and early flight). The kinematics of the ski jumping movement were recorded by four inertial sensors, attached to the thigh and shank of junior athletes, for 40 jumps performed during indoor conditions and 36 jumps in field conditions. An algorithm was designed to detect temporal events from the recorded signals and to estimate the duration of each phase. These durations were evaluated against a reference camera-based motion capture system and by trainers conducting video observations. The precision for the take-off release and take-off durations (indoor < 39 ms, outdoor = 27 ms) can be considered technically valid for performance assessment. The errors for early flight duration (indoor = 22 ms, outdoor = 119 ms) were comparable to the trainers' variability and should be interpreted with caution. No significant changes in the error were noted between indoor and outdoor conditions, and individual jumping technique did not influence the error of take-off release and take-off. Therefore, the proposed system can provide valuable information for performance evaluation of ski jumpers during training sessions.     

The rating of perceived exertion predicts intermittent vertical jump demand and performance

The aims of this study were (a) to assess the ability of the rating of perceived exertion (RPE) to predict performance (i.e. number of vertical jumps performed to a fixed jump height) of an intermittent vertical jump exercise, and (b) to determine the ability of RPE to describe the physiological demand of such exercise. Eight healthy men performed intermittent vertical jumps with rest periods of 4, 5, and 6 s until fatigue. Heart rate and RPE were recorded every five jumps throughout the sessions. The number of vertical jumps performed was also recorded. Random coefficient growth curve analysis identified relationships between the number of vertical jumps and both RPE and heart rate for which there were similar slopes. In addition, there were no differences between individual slopes and the mean slope for either RPE or heart rate. Moreover, RPE and number of jumps were highly correlated throughout all sessions (r = 0.97-0.99; P < 0.001), as were RPE and heart rate (r = 0.93-0.97; P < 0.001). The findings suggest that RPE can both predict the performance of intermittent vertical jump exercise and describe the physiological demands of such exercise.     

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.     

火针治疗对大鼠跟腱末端病细胞凋亡的影响

目的观察火针治疗前后大鼠跟腱末端区细胞凋亡情况的变化,探讨火针治疗末端病的作用机理,为末端病的火针治疗提供理论依据。方法采用"电击跳跃法"建立大鼠跟腱末端病模型,施以火针治疗,采用TUNEL法检测细胞凋亡指数(AI)。结果(1)1次火针治疗后,治疗组大鼠末端区主要在跟腱、纤维软骨区、腱围这三个部位的AI比对照组有不同程度降低;(2)经4次火针治疗后,跟腱、纤维软骨区、腱骨关节面软骨、腱围的AI明显低于对照组;(3)4次火针治疗后在跟腱、纤维软骨区、腱骨关节面软骨、腱围的AI明显低于1次火针治疗组。结论(1)8周的"电击跳跃法"成功建立了大鼠跟腱末端病模型。(2)1次火针治疗可以减少末端区的细胞凋亡和修复已凋亡的细胞。(3)4次火针治疗不仅使末端区的凋亡细胞得到修复,而且加速了整个末端区组织和结构的恢复。