Effects of the Nordic Hamstring exercise on sprint capacity in male football players: a randomized controlled trial

This assessor-blinded, randomized controlled superiority trial investigated the efficacy of the 10-week Nordic Hamstring exercise (NHE) protocol on sprint performance in football players.

Thirty-five amateur male players (age: 17–26 years) were randomized to a do-as-usual control group (CG; n = 17) or to 10-weeks of supervised strength training using the NHE in-season (IG; n = 18). A repeated-sprint test, consisting of 4 × 6 10 m sprints, with 15 s recovery period between sprints and 180 s between sets, was conducted to evaluate total sprint time as the primary outcome. Secondary outcomes were best 10 m sprint time (10mST) and sprint time during the last sprint (L10mST). Additionally, peak eccentric hamstring strength (ECC-P_HS) and eccentric hamstring strength capacity (ECC-CAP_HS) were measured during the NHE.

Ten players were lost to follow-up, thus 25 players were analyzed (CG n = 14; IG n = 11). Between-group differences in mean changes were observed in favor of the IG for sprint performance outcomes; TST (?0.649 s, p = 0.056, d = 0.38), 10mST (?0.047 s, p = 0.005, d = 0.64) and L10mST (?0.052 s, p = 0.094, d = 0.59), and for strength outcomes; ECC-P_HS (62.3 N, p = 0.006, d = 0.92), and ECC-CAP_HS (951 N, p = 0.005, d = 0.95).

In conclusion, the NHE showed small-to-medium improvements in sprint performance and large increases in peak eccentric hamstring strength and capacity.

Trial Registration Number: NCT02674919     

Back to the Future – in support of a renewed emphasis on generic agility training within sports-specific developmental pathways

Perhaps as a consequence of increased specialism in training and support, the focus on engendering and maintaining agility as a generic quality has diminished within many contemporary sports performance programmes. Reflecting this, we outline a rationale suggesting that such a decreased focus represents an oversight which may be detrimental to maximising the potential of performers. We present an evidence-based argument that both generic and specific elements of agility performance should be consistently emphasised within long-term performance-training programmes. We contend that prematurely early specialisation in athlete development models can diminish focus on generic movement skill development with a subsequent detriment in adult performance. Especially when this is coupled with poor primary physical education and limited movement experiences. More speculatively, we propose that generic agility can play a role in operationalising movement development through facilitating skill transfer: thereby enabling the learning of new skills, reduce incidence of injury and facilitating re-learning of old skills during rehabilitation and Return-to-Play processes.     

Heart rate and movement pattern in street soccer for homeless women

Street soccer has been shown to be effective in improving cardiovascular and musculoskeletal fitness in homeless men, due to high heart rate (HR) and multiple intense actions. The purpose of this study was to investigate HR, movement pattern, rating of perceived exertion (RPE), flow and worry during street soccer for homeless women. Fifteen homeless women (30.3?±?5.0?years [± standard deviation, SD], 1.65?±?0.08?m, 65.1?±?11.0?kg, 5?±?4?years football experience) from three countries participated in 4?a-side street soccer games in Women’s Homeless World Cup 2015. Mean and peak HR were 174?±?7 and 188?±?10?beats per minute (bpm), respectively, and >160 bpm 76?±?23% of the playing time (11.1?±?2.6?min). Distance covered per minute was 68.6?±?8.9?m of which 82?±?14, 15?±?6 and 3?±?3% were covered with low- (0–9?km/h), moderate- (9–13?km/h) and high-speed (>13?km/h) running, respectively. The 43?±?5, 45?±?3 and 12?±?3% of the distance were covered running forward, sideways, and backward, respectively. Player Load was 9.2?±?1.7?arbitrary units (AU) per minute and the number of accelerations >1.5?ms^–2 was 15.3?±?2.7 per minute. The score for flow was high (5.5?±?0.8), whereas rating of perceived exertion (RPE) values (4.8?±?2.5) and the score for worry (4.6?±?1.3) were moderate. Street soccer for homeless women elicits high HR and a movement pattern comparable and for some parameters even higher than street soccer and recreational football for homeless and untrained men. Street soccer may be a suitable training intervention for homeless women, and especially moderate RPE and high flow score speaks in favour of an expectation of high participation and adherence.     

球类比赛数学模拟竞技诊断的理论与实践--以乒乓球比赛分析为例

介绍了球类比赛数学模拟竞技诊断的理论与方法,并用乒乓球比赛的数学模拟竞技诊断实例进行了说明。数学模拟竞技诊断的基本思想是用一个比赛状态(技术或战术)转移概率矩阵概括地描述一场球类比赛,在此基础上通过马尔可夫链计算比赛获胜概率并进一步确定各种比赛状态(技术或战术)的竞技效率值。与传统的球类比赛分析方法相比较,数学模拟竞技诊断不但能通过各种比赛状态的转移概率对技、战术进行描述性统计分析,而且能确定各种比赛状态(技术或战术)对整场比赛获胜概率的影响。     

Task Characteristics and Learning Potentials—Empirical Results of Three Diary Studies on Workplace Learning

Most learning in the workplace occurs while pursuing working rather than learning goals. The studies at hand aimed to identify task characteristics that foster learning in the workplace. Task characteristics are supposed to exert a major effect on the learning potential. However, the fact that learning is more often than not a rather unconscious by-product of working poses methodological challenges because respondents might not be capable of accurately recalling daily work experiences. Diaries were applied in order to bring measurement closer to the processes. Three diary studies were conducted in the field of office work within vocational education and training, with trainees requested to record particular work tasks several times a day. Each diary record, i.e., each work task, required a rating of ten standardized items relating to task characteristics including the perceived learning potential of the present task. Eighteen trainees aiming to become retail salespersons recorded 488 work tasks, 10 trainees aiming to become bank clerks recorded 1,113 work tasks, and 20 trainees aiming to become industrial clerks recorded 573 work tasks. The aim of these studies was to explain the variance in the perceived learning potentials from further task characteristics using regression analyses. The extent of the explained variance ranged from 46.6 % in study 1 to 77.8 % in study 3. Interestingness, novelty, assistance from others, and feedback turned out to be the best predictors, whereas scope of action even showed negative influences. Practical implications for workplace learning as well as methodological recommendations for using diary methods in the workplace are discussed.     

Quantification of wall surface heterogeneity and its influence on species diversity at medieval castles – implications for the environmentally friendly preservation of cultural heritage

Historic buildings are important for cultural history and provide a variety of habitats for animals and plants. Especially structural heterogeneity of wall surfaces is perceived to support biological diversity. Nevertheless, in traditional approaches goals of biodiversity preservation and monument restoration are perceived to interfere and to be mutually exclusive. As a consequence, priority is often given to constructional restoration accepting the loss of local populations and biodiversity. At walls of medieval castles, including an experimental restoration project where conventional and less intensive restoration techniques were applied, we relate species composition and richness to wall properties. Especially wall surface structure is quantified using a novel approach. The study focuses on lichens, mosses and vascular plants. Boosted regression tree analyses and non-metric multidimensional scaling techniques are applied to detect the influence of abiotic site conditions on biodiversity. We find species richness to be promoted by wall surface heterogeneity. However, species composition is more affected by restoration approaches than species richness. Lichen composition varies considerably while vascular plants and mosses are less affected by wall properties. We suggest strategies that are combining both societal targets, the preservation of historic monuments and of species diversity. Careful restoration is capable of supporting both, the maintenance of cultural heritage and of rare and unique anthropogenic habitats. Wall surface heterogeneity needs to be witnessed for both aspects as it affects both species composition as well as the effectiveness of cleaning methods.     

Epistemic Beliefs in Science—A Systematic Integration of Evidence From Multiple Studies

Educational Psychology Review - Recent research has integrated developmental and dimensional perspectives on epistemic beliefs by implementing an approach in which profiles of learners’...     

Möglichkeiten außerschulischer Hilfen in der Bearbeitung von Bildungsbenachteiligung: Potenziale und Grenzen ausgewählter Handlungsfelder der Jugendsozialarbeit

Even though social inequalities in education are often dealt with in out-of-school social work programs, this has been largely neglected by educational research in recent years. The present paper therefore presents the different fields of action in youth social work as means of compensatory education and discusses research findings regarding its use and effectiveness. The difficulty of measuring their effectiveness is not only due to a fragmented research field, but also reflects the fundamental contradiction between structural problems and their pedagogical treatment. The paper ends with a reflection on the importance of out-of-school programs to help adolescents with difficult course of lives.     

Entrepreneurial orientation in turbulent environments: The moderating role of absorptive capacity

The literature on entrepreneurial orientation (EO) has confirmed the positive relationship between EO and firm performance and that relationship's dependence on several contingencies. The present study connects the resource-based view and its dynamic capability extension to introduce absorptive capacity (ACAP) as a moderator of the relationship between EO and firm performance. This theoretically derived research model is empirically validated using survey data from 219 small and medium-sized enterprises in Germany. Our empirical findings are that ACAP strengthens the EO–performance relationship in turbulent markets.