Prevalence and determinants of symptoms of common mental disorders in retired professional Rugby Union players

The primary aim of this study was to determine the prevalence of symptoms of common mental disorders (CMD) (distress, anxiety/depression, sleeping disturbance, adverse nutrition behaviour, adverse alcohol behaviour and smoking) among retired professional Rugby Union players. The secondary aim was to explore the associations between stressors (life events, Rugby Union career dissatisfaction) and the health conditions under study. Therefore, cross-sectional analyses were conducted on baseline questionnaires from an ongoing prospective cohort study of retired professional Rugby Union players. An electronic questionnaire was established using validated questionnaires to assess symptoms of CMD and stressors. The electronic questionnaire was subsequently distributed to retired players by the national Rugby Union players’ associations in France, Ireland and South Africa. Among 295 retired professional Rugby Union players (mean age of 38 years), prevalence rates were 25% for distress, 28% for anxiety/depression, 29% for sleeping disturbance, 62% for adverse nutrition behaviour, 15% for smoking and 24% for adverse alcohol behaviour. A higher number of life events were associated with distress (OR?=?1.2; 95% CI 1.1–1.4), anxiety/depression (OR?=?1.6; 95% CI 1.2–2.1), sleeping disturbance (OR?=?1.6; 95% CI 1.2–2.1) and adverse nutrition behaviour (OR?=?1.8; 95% CI 1.3–2.5). A higher level of dissatisfaction of the player's Rugby Union career was associated with distress (OR?=?0.9; 95% CI 0.8–1.0), sleeping disturbance (OR?=?0.9; 95% CI 0.9–1.0), smoking (OR?=?0.9; 95% CI 0.9–1.0) and adverse nutrition behaviour (OR?=?0.9; 95% CI 0.8–0.9). In conclusion, our study suggests that prevalence of symptoms of CMD is high among retired professional Rugby Union players, being associated with both a higher number of life events and a higher level of Rugby Union career dissatisfaction.     

Relationship between the peak time of hamstring stretch and activation during sprinting

The purpose of this study was to investigate the time series relationships between the peak musculotendon length and electromyography (EMG) activation during overground sprinting to clarify the risk of muscle strain injury incidence in each hamstring muscle. Full-body kinematics and EMG of the right biceps femoris long head (BFlh) and semitendinosus (ST) muscles were recorded in 13 male sprinters during overground sprinting at maximum effort. The hamstring musculotendon lengths during sprinting were computed using a three-dimensional musculoskeletal model. The time of the peak musculotendon length, in terms of the percentage of the running gait cycle, was measured and compared with that of the peak EMG activity. The maximum length of the hamstring muscles was noted during the late swing phase of sprinting. The peak musculotendon length was synchronous with the peak EMG activation in the BFlh muscle, while the time of peak musculotendon length in the ST muscle occurred significantly later than the peak level of EMG activation (p < 0.05). These results suggest that the BFlh muscle is exposed to an instantaneous high tensile force during the late swing phase of sprinting, indicating a higher risk for muscle strain injury.     

Adding omega-3 fatty acids to a protein-based supplement during pre-season training results in reduced muscle soreness and the better maintenance of explosive power in professional Rugby Union players

Evidence suggests that omega-3 fatty acid supplementation could reduce muscle soreness and maintain muscle function following eccentric exercise-induced muscle damage. The aim of this applied field study was to investigate the effectiveness of consuming a protein-based supplement containing 1546?mg of omega-3 polyunsaturated fatty acid (PUFA) (551?mg eicosapentaenoic acid (EPA) and 551?mg docosahexaenoic acid (DHA)) twice daily (FO) compared to a protein-based placebo (P) on muscle soreness, countermovement jump (CMJ) performance and psychological well-being in 20 professional Rugby Union players during 5 weeks of pre-season training. Players completed a 5-point-Likert soreness scale with 5 indicating “no soreness” and a questionnaire assessing fatigue, sleep, stress and mood each morning of training, plus they performed CMJ tests once or twice per week. Data were analysed using magnitude-based inferential statistics and are presented as percent beneficial/trivial/harmful. On day 35, there was a likely (% beneficial/trivial/harmful: 94/5/1) moderate (0.75, standardized mean difference (SMD)) beneficial effect of FO vs. P on the change in lower body muscle soreness compared with day 0 (FO: ?3.8?±?21.7%; P: ?19.4?±?11.2%). There was a likely (92/7/0) moderate (SMD: 0.60) beneficial effect of FO vs. P on CMJ performance (change from baseline to day 35, FO: +4.6?±?5.9%; P: ?3.4?±?8.6%). From day 20, a moderate beneficial effect of FO on fatigue was observed. In terms of practical relevance, the moderate beneficial effect of adding fish oil to a protein-based supplement on muscle soreness translated into the better maintenance of explosive power in elite Rugby Union players during pre-season training.     

我国居民体育消费水平影响因素分析

体育消费水平是衡量一个国家体育产业和人民生活水平的一个重要指标。在文献资料的基础上进行广泛的分析与研究 ,进行了因子分析。认为影响居民体育消费水平的因素是多方面的 ,有经济因素、社会因素、政治因素、个人因素、体育因素等等。其中 ,体育因素、经济因素占有核心的位置。     

试析影响竞走裁判员准确判罚的客观因素

竞走比赛中多种客观因素对裁判员准确判罚的影响是客观存在的现实。裁判员对判罚尺度的掌握及对各种技术的认同，将对竞走运动的发展及对运动员的成长产生巨大的影响。     

影响大学生体质健康的因素分析

采用问卷调查、文献资料等方法,分析了学校、体育教师和学生在体育工作和体育活动方面存在的不足,进而将学校的体育工作同增强学生体质、增进学生健康有机地结合起来。     

Effect of the coefficient of friction of a running surface on sprint time in a sled-towing exercise

This study investigated the effect of the coefficient of friction of a running surface on an athlete's sprint time in a sled-towing exercise. The coefficients of friction of four common sports surfaces (a synthetic athletics track, a natural grass rugby pitch, a 3G football pitch, and an artificial grass hockey pitch) were determined from the force required to tow a weighted sled across the surface. Timing gates were then used to measure the 30-m sprint time for six rugby players when towing a sled of varied weight across the surfaces. There were substantial differences between the coefficients of friction for the four surfaces (μ = 0.21–0.58), and in the sled-towing exercise the athlete's 30-m sprint time increased linearly with increasing sled weight. The hockey pitch (which had the lowest coefficient of friction) produced a substantially lower rate of increase in 30-m sprint time, but there were no significant differences between the other surfaces. The results indicate that although an athlete's sprint time in a sled-towing exercise is affected by the coefficient of friction of the surface, the relationship relationship between the athlete's rate of increase in 30-m sprint time and the coefficient of friction is more complex than expected.     

The influence of hand positions on biomechanical injury risk factors at the wrist joint during the round-off skills in female gymnastics

The aim of this study was to examine the biomechanical injury risk factors at the wrist, including joint kinetics, kinematics and stiffness in the first and second contact limb for parallel and T-shape round-off (RO) techniques. Seven international-level female gymnasts performed 10 trials of the RO to back handspring with parallel and T-shape hand positions. Synchronised kinematic (3D motion analysis system; 247 Hz) and kinetic (two force plates; 1235 Hz) data were collected for each trial. A two-way repeated measure analysis of variance (ANOVA) assessed differences in the kinematic and kinetic parameters between the techniques for each contact limb. The main findings highlighted that in both the RO techniques, the second contact limb wrist joint is exposed to higher mechanical loads than the first contact limb demonstrated by increased axial compression force and loading rate. In the parallel technique, the second contact limb wrist joint is exposed to higher axial compression load. Differences between wrist joint kinetics highlight that the T-shape technique may potentially lead to reducing these bio-physical loads and consequently protect the second contact limb wrist joint from overload and biological failure. Highlighting the biomechanical risk factors facilitates the process of technique selection making more objective and safe.     

Validity of a trunk-mounted accelerometer to assess peak accelerations during walking,jogging and running

Abstract

The purpose of this study was to validate peak acceleration data from an accelerometer contained within a wearable tracking device while walking, jogging and running. Thirty-nine participants walked, jogged and ran on a treadmill while 10 peak accelerations per movement were obtained (n = 390). A single triaxial accelerometer measured resultant acceleration during all movements. To provide a criterion measure of acceleration, a 12-camera motion analysis (MA) system tracked the position of a retro-reflective marker affixed to the wearable tracking device. Peak raw acceleration recorded by the accelerometer significantly overestimated peak MA acceleration (P < 0.01). Filtering accelerometer data improved the relationship with the MA system (P < 0.01). However, only the 10 Hz and 8 Hz cut-off frequencies significantly reduced the errors found. The walk movement demonstrated the highest accuracy, agreement and precision and the lowest relative errors. Linear increases in error were observed for jog compared with walk and for run compared to both other movements. As the magnitude of acceleration increased, the strength of the relationship between the accelerometer and the criterion measure decreased. These results indicate that filtered accelerometer data provide an acceptable means of assessing peak accelerations, in particular for walking and jogging.     

The importance of duration and magnitude of force application to sprint performance during the initial acceleration,transition and maximal velocity phases

ABSTRACT

Successful sprinting depends on covering a specific distance in the shortest time possible. Although external forces are key to sprinting, less consideration is given to the duration of force application, which influences the impulse generated. This study explored relationships between sprint performance measures and external kinetic and kinematic performance indicators. Data were collected from the initial acceleration, transition and maximal velocity phases of a sprint. Relationships were analysed between sprint performance measures and kinetic and kinematic variables. A commonality regression analysis was used to explore how independent variables contributed to multiple-regression models for the sprint phases. Propulsive forces play a key role in sprint performance during the initial acceleration (r = 0.95 ± 0.03) and transition phases (r = 0.74 ± 0.19), while braking duration plays an important role during the transition phase (r = ?0.72 ± 0.20). Contact time, vertical force and peak propulsive forces represented key determinants (r = ?0.64 ± 0.31, r = 0.57 ± 0.35 and r = 0.66 ± 0.30, respectively) of maximal velocity phase performance, with peak propulsive force providing the largest unique contribution to the regression model for step velocity. These results clarified the role of force and time variables on sprinting performance.     

大学体育教育中影响学生学习动机诸因素分析及其对策的研究

在高校体育教育过程中，要激发巩固学生的学习动机并保持较高水平，应充分利用“兴趣”因素，在教学中增加体育文化的内容；改革和加强高校体育的行政职能管理，应借鉴高校思想系列的相关方法，设立体育辅导员与体育指导员的管理制度；把高校和社区的健身、养生活动融为一体，实施资源共享，优势互补，引进输出并举，给学校健身市场的培育、发展注入市场活力。     

鄂西北地区体育旅游产业发展影响因素分析

运用特尔非法和层次分析法,分析鄂西北地区体育旅游产业发展的影响因素。指出体育旅游产业发展受政策环境、旅游资源、管理服务、人文环境、基础条件等因素的影响。鄂西北地区体育旅游产业发展需要加快交通运输等基础设施建设,充分挖掘体育旅游文化资源,以品牌战略和提高管理服务质量为主,合理布局区域体育旅游发展格局,形成产业发展的合力,从而带动整个地区经济社会的发展,实现发展方式的转变。     

Contributions of the muscular torques and motion-dependent torques to generate rapid elbow extension during overhand baseball pitching

Some studies have reported that overarm baseball pitching shows a proximal to distal sequential joint motion including a rapid extension of the elbow. It has been suggested that the rapid elbow extension just before ball release is not due to the action of the elbow extensor muscles, but the underlying mechanisms are not so clear. The purpose of this study was to determine the contributions of each joint muscular- and motion-dependent torques, including the upper trunk and throwing arm joints to generate the rapid elbow extension during baseball pitching. The right handed throwing motions of three baseball pitchers were recorded using five high-speed video cameras and the positional data were calculated using the direct linear transformation method. A throwing arm dynamic model of the upper trunk and throwing arm joints was then used, including 10 degrees of freedom, to calculate the throwing arm joint muscular-, throwing arm and upper trunk joint motion-, gravity-, and external force-dependent components that contribute to the maximum elbow extension angular velocity. The results showed that the rapid elbow extension was primarily due to the upper trunk counterclockwise rotation and shoulder horizontal adduction angular velocity-dependent torques. This study implied that the trunk counterclockwise rotators and shoulder horizontal adductors generate positive torques to maintain the angular velocities of the upper trunk counterclockwise rotation and shoulder horizontal adduction may play a key role in producing the rapid elbow extension.     

影响广州市高校离退休知识分子生活质量的因素分析

通过对广州市高校离退休知识分子生活现状的调查,分析了他们生活质量中存在的问题,阐述了影响他们生活质量的诸多因素,从而使社会更加关注高校离退休知识分子的生活质量,同时为社区老年保健规划提供科学依据。     

An examination of the Clegg impact hammer test with regard to the playing performance of synthetic sports surfaces

One of the tests used to evaluate the performance of sports surfaces measures the peak deceleration of a rigid mass during contact with the surface, after being dropped from a set height. It is widely used and is included in a number of international standards. The test was carried out using two drop heights on four different designs of artificial cricket pitch, with a full set of acceleration data being collected over the duration of impact. These data were then integrated twice with respect to time to produce velocity and displacement information. Oblique impacts of cricket balls were also carried out and analysed using a high-speed video system to evaluate the playing performance of each pitch design. It was found that, although the pitches gave quite different readings of peak deceleration, they produced similar values for coefficient of restitution and were therefore considered to ‘play’ in a very similar way. This was due to a high peak deceleration reading being accompanied by a short contact time and low peak deceleration being accompanied by a long contact time, meaning that the change in momentum was similar in both cases. It was concluded that for accelerometer tests to be useful, all the acceleration-time data should be analysed, rather than the peak value alone.     

维生素pp对有氧代谢和无氧代谢运动能力影响的分析

维生素pp对人体的健康起着重要作用,同时与人体运动能力的关系非常密切,它以其特有的方式参与有氧代谢和无氧代谢供能,且有生理保健功能。本文在分析维生素pp参与物质代谢的基础上,推断出维生素PP对有氧代谢运动能力的影响大于对无氧代谢运动能力的影响。     

Reproducibility of the maximum accumulated oxygen deficit and run time to exhaustion during short-distance running

The aim of this study was to determine the reproducibility of the maximal accumulated oxygen deficit and the associated exercise time to exhaustion during short-distance running. Fifteen well-trained males (mean - s : VO 2max = 58.0 - 4.6 ml.kg -1 .min -1 ) performed the maximum accumulated oxygen deficit test at an exercise intensity equivalent to 125% VO 2max . The test was repeated at the same time of day on three occasions within 3 weeks. There was no significant systematic bias between trials for either maximum accumulated oxygen deficit (mean - s : trial 1 = 69.0 - 13.1; trial 2 = 71.4 - 12.5; trial 3 = 70.4 - 15.0 ml O 2 Eq.kg -1 ; ANOVA, F = 0.70, P = 0.51) or exercise time to exhaustion (trial 1 = 194 - 31.1; trial 2 = 198 - 33.2; trial 3 = 201 - 36.8 s; F = 1.49, P = 0.24). In addition, other traditional measures of reliability were also favourable. These included intraclass correlation coefficients of 0.91 and 0.87, and sample coefficients of variation of 6.8% and 5.0%, for maximum accumulated oxygen deficit and exercise time to exhaustion respectively. However, the '95% limits of agreement' were 0 - 15.1 ml O 2 Eq (1.01 2 / 1 1.26 as a ratio) and 0 - 33.5 s (1.0 2 / 1 1.18 as a ratio) for maximum accumulated oxygen deficit and exercise time to exhaustion respectively. We estimate that the sample sizes required to detect a 10% change in exercise time to exhaustion and maximum accumulated oxygen deficit after a repeated measures experiment are 10 and 20 respectively. Unlike the results of previous maximum accumulated oxygen deficit studies, we conclude that it is not a reliable measure.     

Primary mechanical factors contributing to foot eversion moment during the stance phase of running

Rearfoot external eversion moments due to ground reaction forces (GRF) during running have been suggested to contribute to overuse running injuries. This study aimed to identify primary factors inducing these rearfoot external eversion moments. Fourteen healthy men ran barefoot across a force plate embedded in the middle of 30-m runway with 3.30 ± 0.17 m · s^–1. Total rearfoot external eversion/inversion moments (Mtot) were broken down into the component Mxy due to medio-lateral GRF (Fxy) and the component Mz due to vertical GRF (Fz). Ankle joint centre height and medio-lateral distance from the centre of pressure to the ankle joint centre (a_cop) were calculated as the moment arm of these moments. Mxy dominated Mtot just after heel contact, with the magnitude strongly dependent on Fxy, which was most likely caused by the medio-lateral foot velocity before heel contact. Mz then became the main generator of Mtot throughout the first half of the stance phase, during which a_cop was the critical factor influencing the magnitude. Medio-lateral foot velocity before heel contact and medio-lateral distance from the centre of pressure to the ankle joint centre throughout the first half of the stance phase were identified as primary factors inducing the rearfoot external eversion moment.