Sex differences in elbow and wrist joint loading during the cartwheel and round off with different hand positions performed by young gymnasts

The aim of the study was to determine if sex differences exist in the key elbow and wrist joint injury risk factors during different cartwheel (CW) and round-off (RO) techniques performed by young male and female artistic gymnasts. Sixteen active young gymnasts (8 males and 8 females) performed 30 successful trials of CW and RO with three different hand positions (parallel (10), T-shape (10) and reverse (10)). Synchronised kinematic and kinetic data were collected for each trial. Two-way repeated measures ANOVA (3 × 2, technique × sex) and effect-sizes (ES) were used for statistical analysis. In conclusion, female gymnasts exhibited greater normalised peak vertical ground reaction forces (VGRF), elbow and wrist compression forces and elbow internal adduction moments during CW and RO skills compared with male gymnasts. In both sexes, the parallel and reverse techniques increased peak VGRF, elbow and wrist compression forces and the elbow internal adduction moment. Increased elbow flexion resulted in decreased peak VGRF, elbow compression forces and elbow internal adduction moment. Injury risk factors including elbow extension and internal adduction moment with axial compression force suggest that a CW and RO in reverse and parallel techniques can be hazardous especially for young female gymnasts.     

Between-limb differences in running technique induces asymmetric negative joint work during running

Negative work, which is mainly generated by eccentric muscle contraction, has an important influence on the associated muscle damage. Generally, mechanical parameters are determined for one side of a lower extremity on the assumption of negligible between-limb differences. However, between-limb differences in the negative work of lower extremity joints during running remain unclear. This study examines between-limb differences in negative work and associated mechanical parameters during the contact phase of running. Twenty-five young adult males voluntarily participated in this study. Each participant was asked to run on a straight runway at a speed of 3.0?m?s^?1. Negative work, amplitude, duration of negative power, moment, and angular velocity were computed for both sides of the lower extremities. Significant differences were found in negative work between limbs for the hip (18.9?±?11.7%), knee (13.6?±?10.4%), and ankle (11.8?±?8.5%) joints. For the hip joint, asymmetric negative work was attributable to the between-limb difference in the amplitude of negative power owing to a corresponding difference in the moment. The between-limb differences concerning the duration and amplitude of negative power could explain the asymmetric negative work in the knee joint. The asymmetric negative work of the ankle joint was attributable to the between-limb difference in the amplitude and duration of the negative power and the moment. These results indicate that asymmetric negative work was generated in each lower extremity joint; however, the major mechanical parameters corresponding to the negative work are not the same across the joints.     

东京奥运会延期举办背景下东道主形象修复策略研究

新冠疫情对东京奥运会各项筹办工作和东道主形象产生了负面的影响,日本方面因时而变、因势利导,积极引导国际舆论走向,维护奥运会东道主的良好形象。东京奥运会延期举办事件的决策过程经历了4个发展阶段,对东京奥运会延期举办背景下各方定义的新闻议程进行了分析,结合新闻议程内容对奥运会东道主形象修复策略展开了研究。日本方面根据全球疫情变化、本国疫情防控形势和国际舆论走向,针对不同的发展阶段,采取了建立信心、推卸责任、拖延、诚意等形象修复策略,试图强化人们对于东京奥运会东道主安全条件的形象认知,致力于维护日本"安全之手"的国际形象,增强世界各国对于东京奥运会顺利举办的信心,在危机应对中实现国家利益最大化,其中不乏成功经验值得借鉴参考。     

青少年网球运动员如何预防网球运动中的损伤

青少年网球运动员由于受年龄等因素的影响,在参与运动中损伤的比例也正呈现出逐年上升的趋势。因此,如何减少、预防网球运动中的损伤,已是当务之急,不仅对青少年网球运动员提高运动成绩有着密切的关系,还对他们以后的就业、生活等产生一系列的影响。     

中学生体育训练常见损伤的原因及预防探析

中学生体育训练经常出现各种运动损伤,运动损伤将会给中学生的学习和生活带来负面影响。采用文献资料调研法,访谈法对中学生体育训练常见的运动损伤情况,及其产生的原因进行了分析,并就如何预防运动损伤提出了一些建议和预防要注意的原则。     

A knock to the system: A new sociotechnical systems approach to sport-related concussion

Broader contextual factors that influence concussion management have tended to be overlooked. To address this, the present study used a sociotechnical systems approach to identify perceived responsibilities and applied strategies for three domains of concussion management (i.e., prevention, identification and treatment). Participants were 118 members of the community rugby union system in Australia (69.2% male). Participants from throughout the rugby system (e.g., players, parents, coaches, club management) were asked open-ended questions about their perceived responsibilities and the strategies they use for concussion management. It was found that (a) proper training, technique correction and education were recurrent prevention themes; (b) the majority of key stakeholders felt that they could consistently identify concussion; however, medical aids (medics) were the only system actors who stated a responsibility to use standardised concussion assessment measures and (c) less than one third of the respondents indicated their involvement in treating concussion. This study identifies specific junctures in the system that prevents effective concussion management strategies. A sociotechnical systems approach improves the understanding of concussion prevention, and management beliefs and behaviours.     

Compelling overuse injury incidence in youth multisport athletes

The present investigation was carried out to examine the incidence and pattern of injuries in adolescent multisport athletes from youth sports academy. Injury data were prospectively collected from 166 athletes during the seasons from 2009 to 2014. A total of 643 injuries were identified, 559 (87.0%) were time-loss injuries. The overall injury incidence was 5.5 (95% confidence interval CI: 5.1–6.0), the incidence of time-loss injuries was 4.8 (95% CI: 4.4–5.2), the incidence of growth conditions was 1.2 (95% CI: 1.0–1.4) and incidence of serious injuries was 0.6 (95% CI: 0.5–0.8) per 1000?h of exposure. The prevalence of overuse injuries was 50.3%. Growth conditions represented 20.0%. Most of the injuries (67.0%) involved the lower extremities, and both foot and ankle were the most predominant injured body parts (22.0%). Knee injuries were mostly from overuse (50 vs. 23, p?=?.02), whereas foot and ankle injuries resulted from an acute mechanism (94 vs. 31, p?<?.0001). Minor and moderate injuries accounted for 87.0%. Muscle, tendon and osteochondrosis injuries accounted for 52.0% of all injuries. Comparing groups, squash sport was having the highest injury incidence (8.5 injuries per athlete). Higher exposure was associated with greater overuse relative risk (RR?=?1.03, 95% CI: 1.01–1.014, p?<?.001). In conclusion, the results of this study identified a high incidence of injuries in this youth sports population. Striking was the prevalence of overuse injuries of 50%, which suggests the need for injury prevention protocols for adolescent highly trained athletes.     

Acute fatigue negatively affects risk factors for injury in trained but not well-trained habitually shod runners when running barefoot

Introduction: Many factors may contribute to running-related injury. These include fatigue and footwear, the combination of which has rarely been studied, in particular with reference to barefoot running, recently advocated as a method to reduce injury risk. Methods: Twenty-two runners (12 well-trained and 10 trained) participated in a 10?km fatiguing trial. Knee and ankle joint kinematics and kinetics and electromyography were assessed during overground running in the barefoot and shod condition. This was performed pre- and post-fatigue using a motion capture system and force platforms. Results: Initial loading rate increased in the trained runners when barefoot but not shod. Shod knee stiffness increased in both groups after fatigue, whereas barefoot knee stiffness decreased only in the trained group. A reduction in barefoot bicep femoris pre-activation was found in both groups. During stance, a reduction in vastus lateralis and biceps femoris and an increase in tibialis anterior activity were found over time in both groups and conditions. Trained runners decreased gluteus medius and increased lateral gastrocnemius median frequency for both conditions after fatigue. Conclusion: When fatigued, gait adjustments in habitually shod runners may increase injury risk when running barefoot. Training status may be a risk factor for injury, as less-trained runners experience muscular fatigue changes that may compromise ground reaction force attenuation. Caution is recommended when transitioning to pure barefoot running.     

Could Slackline Training Complement the FIFA 11+ Programme Regarding Training of Neuromuscular Control?

The current study compared changes in neuromuscular control between slackline training and the stabilization training elements of the FIFA 11+ programme. Twenty-five students in 2 groups performed a 12-unit training programme. The slackline training group (n?=?13) exclusively trained with a slackline. The stabilization training group (n?=?12) practised exercises as described in the second part of the FIFA 11+ programme. Improvements in balance were assessed using three tests for dynamic, quasi-static, and perturbed postural control: the star excursion balance test (SEBT), the closed-eye single-leg stance, and the MFT S3-Check. Both groups significantly improved the stability and sensorimotor index of the MFT S3-Check (p?<?.001), their range on the SEBT (p?<?.001), and the duration of closed-eye single-leg stance (p?<?.001). The group?×?training interaction was significant for the MFT S3-Check (stability index: p?=?.042; sensorimotor index: p?=?.004) and the SEBT (dominant leg: p?=?.003; averaged both legs: p?=?.016), with the slackline training group showing a larger training effect than the stabilization training group. The results of the present study suggest that slackline training offers similar – or better – improvements in neuromuscular control as the FIFA 11+ warm-up programme. If compliance with the FIFA 11+ programme is declining, then slacklining might offer an alternative approach to reach the training goals of improved sensorimotor control.     

女子足球运动员踝关节损伤的调查与分析

通过文献资料方法、调查问卷法等相关方法,对女子足球运动员的运动损伤的进行调查分析,结果显示女子足球运动员的踝关节损伤者较为普遍。对运动损伤的原因进行分析,并提出了相应的预防措施,加强健康保健意识等预防治疗措施,旨在一定程度上减少女子足球运动员的损伤发生。以最大限度减少足球运动中的踝关节损伤。