Return to sport and beyond following intramuscular tendon hamstring injury: A case report of an English Premier League football player

BackgroundHamstring strain injuries are the most common type of injury in elite football and are associated with a high risk of reinjury, particularly those involving the intramuscular tendon (IMT). Limited information is available regarding the rehabilitation and return to sport (RTS) processes following such injuries. This case study describes the clinical presentation of an elite football player following IMT hamstring injury, their on- and off-pitch rehabilitation alongside performance monitoring throughout RTS and beyond.Case scenarioAn elite football player suffered a grade 2c hamstring injury during an English Premier League (EPL) match. The player underwent early post-injury management, alongside progressive off-pitch physical preparation. The ‘control-chaos continuum’ was used as a framework for on-pitch rehabilitation to prepare the player for a return to full team training and competition. Objective and subjective markers of the player's response to progressive on- and off-pitch loading were monitored throughout RTS and beyond.OutcomesThe player returned to on-pitch rehabilitation after 11 days, to full team training having achieved weekly pre-injury chronic running load outputs after 35 days and played in the EPL 40 days post-injury. The player did not suffer reinjury for the rest of the EPL season.ConclusionAn understanding the unique structural and mechanical properties of the IMT, alongside expected RTS timeframes are important to inform rehabilitation and decision-making processes post-injury. Performance and frequent load-response monitoring throughout RTS and beyond, in conjunction with practitioner experience and effective communication are critical in facilitating effective RTS and reduce risk of reinjury following IMT injury.     

Evaluation of six anti-SARS-CoV-2 antibody test kits and practical approaches to optimize the diagnostic performance

In an investigation of six anti-SARS-CoV-2 antibody kits with different target antigen and methodology, each kit showed comparable performance. As false-positive reactions occurred independently with different kits, specificity increased to 100% when pairs of kits were used. With three-kit combination, both sensitivity (99.1%) and specificity (100%) increased.     

Analysis of jump load during a volleyball season in terms of player role

ObjectivesThe aim of this study was to analyze the jump load performed by top-level volleyball players during an entire training season in terms of the player role, training period, type of daily training, and quality of opposition in the subsequent match.DesignLongitudinal panel observational study.MethodsThe total number of jumps performed by players was recorded through 174 training days distributed in 32 weeks during the 2016/2017 season (pre-season, 5 weeks; in-season, 27 weeks). The players role were classified as middle-blocker, outside-hitter, opposite and setter (the libero was omitted). A generalized mixed linear model was performed (with Bonferroni post hoc test at p < 0.05) to assess the effect of training variables and the repeated-measures data of players’ jumps along various training days. Additionally, the effect sizes at 95% confidence intervals were calculated to compare the jump load between players’ role and training variables.ResultsThe results showed a significant and moderate higher amount of jumps performed by middle-blockers regardless the type of macro- or micro-cycle, the micro-cycle phase, the type of training and the quality of match opposition. Contrarily, the setter performs the least jump load in all variables analyzed. Only the players’ role, macro-cycle and micro-cycle phase had significant effects on the player's jump load variation along the season.ConclusionsThis information could be useful to guide the monitoring and preparation process for coaches and physical trainers. These values allow differentiating between players’ role and could be used as references values in order to avoid injuries whereas performance increase along the season.     

碳、氮源对PVA降解混合体系降解能力的影响及PVA降解机理初探

以能完全降解1g／LPVA的一个混合体系为研究对象，研究了碳、氮源对该混合体系降解PVA的影响。实验表明，补充有机氮源有利于混合体系菌体的生长，并且能提高混合体系对PVA的降解能力。进一步的研究发现，其它碳源的补充有利于菌体的生长，但对混合体系降解PVA产生一定的抑制作用。根据初步研究结果推断，该混合体系所产的PVA降解酶主要结合在细胞膜上，部分PVA进入细胞后被降解。     

不同性别中学生青春期学习成绩变化的研究

目的了解和证实是否客观存在青春期后女生学习能力降低的现象。方法收集分析了青岛市某中学高中毕业的一届学生230名女生和197名男生从初中到高中6年内的各次考试成绩。比较了男女学生每次考试的平均总成绩和成绩排名的平均名次。结果男女生之间初中入学时总成绩没有明显差别，但在初中阶段的历次考试中，女生成绩基本上优于男生，名次领先于男生；高中阶段情况出现倒转，女生成绩和名次逐渐落后于男生，并一直持续到高者．结论在所调查的这届学生中，确实存在女性在青春期前后学习能力下降的现象。