Physiological responses and time-motion characteristics of various small-sided soccer games in youth players

The aim of this study was to examine acute physiological responses and time-motion characteristics associated with three different small-sided soccer game formats in youth players. Sixteen male soccer players aged 16.3+/-0.6 years (mean+/-s) completed three variations of a small-sided game (i.e. 2 vs. 2, 4 vs. 4, and 6 vs. 6 players) in which heart rate, rating of perceived exertion (RPE), blood lactate concentration, and time-motion characteristics were recorded. The pitch size was altered to keep the relative pitch area per player consistent for each game format. The 2 vs. 2 games exhibited greater blood lactate, heart rate, and RPE responses compared with 4 vs. 4 and 6 vs. 6 games (P<0.05). The players travelled less (P<0.05) distance at speeds of 0-7 km.h(-1) in the 4 vs. 4 compared with the 2 vs. 2 games (1128+/-10 m and 1176+/-8 m, respectively). Average maximal sprint distances above 18 km.h(-1) were lower (P<0.05) in 2 vs. 2 than in 4 vs. 4 and 6 vs. 6 games (11.5+/-3.9 m, 15.3+/-5.5 m, and 19.4+/-5.9 m, respectively), and in 4 vs. 4 compared with 6 vs. 6 games. The results show that as small-sided game formats decrease in size and relative pitch area remains constant, overall physiological and perceptual workload increases.     

Different systems—Similar challenges? Factors impacting the motivation of German and U.S. teachers to become school leaders

In the United States and Germany, effective school leadership is pivotal to a school's success. Yet in each country, attracting and retaining qualified school leaders is a formidable challenge. This study compares the influence of possible motivators and inhibitors that impact teachers’ decisions to become principals in the two countries. Survey responses of 311 U.S. students in principal preparation programs in the United States and responses of 117 German students in similar programs in Germany indicate that many factors that motivate and inhibit U.S. and German teachers to become school leaders are similar. The results also reveal areas in which the U.S. and Germany may learn from each other regarding motivators and inhibitors to becoming school administrators.     

Energy system contribution to 1500- and 3000-metre track running

The aim of the present study was to quantify the contributions of the aerobic and anaerobic energy systems to 1500- and 3000-m track running events during all-out time-trials performed individually on a synthetic athletic track. Ten 3000-m (8 males, 2 females) and fourteen 1500-m (10 males, 4 females) trained track athletes volunteered to participate in the study. The athletes performed a graded exercise test in the laboratory and two time-trials over 1500 or 3000 m. The contributions of the energy systems were calculated by measures of race oxygen uptake, accumulated oxygen deficit (AOD), race blood lactate concentration, estimated phosphocreatine degradation and some individual muscle metabolite data. The relative aerobic energy system contribution (based on AOD measures) for the 3000 m was 86% (male) and 94% (female), while for the 1500 m it was 77% (male) and 86% (female). Estimates of anaerobic energy expenditure based on blood lactate concentrations, while not significantly different (P > 0.05), were generally lower compared with the AOD measures. In conclusion, the results of the present study conform with some recent laboratory-based measures of energy system contributions to these events.     

Effects of sodium phosphate and caffeine loading on repeated-sprint ability

The effects of sodium phosphate and caffeine supplementation were assessed on repeated-sprint ability. Using a randomised, double-blind, Latin-square design, 12 female, team-sport players participated in four trials: (1) sodium phosphate and caffeine, (2) sodium phosphate and placebo (for caffeine), (3) caffeine and placebo (for sodium phosphate) and (4) placebo (for sodium phosphate and caffeine), with ~21 days separating each trial. After each trial, participants performed a simulated team-game circuit (4 × 15 min quarters) with 6 × 20-m repeated-sprints performed once before (Set 1), at half-time (Set 2), and after end (Set 3). Total sprint times were faster after sodium phosphate and caffeine supplementation compared with placebo (Set 1: P = 0.003; Set 2: d = ?0.51; Set 3: P < 0.001; overall: P = 0.020), caffeine (Set 3: P = 0.004; overall: P = 0.033) and sodium phosphate (Set 3: d = ?0.67). Furthermore, total sprint times were faster after sodium phosphate supplementation compared with placebo (Set 1: d = ?0.52; Set 3: d = ?0.58). Best sprint results were faster after sodium phosphate and caffeine supplementation compared with placebo (Set 3: P = 0.007, d = ?0.90) and caffeine (Set 3: P = 0.024, d = ?0.73). Best sprint times were also faster after sodium phosphate supplementation compared with placebo (d = ?0.54 to ?0.61 for all sets). Sodium phosphate and combined sodium phosphate and caffeine loading improved repeated-sprint ability.     

Community characteristics associated with child abuse in Iowa

PROBLEM: Various demographic and community characteristics are associated with child abuse rates in national and urban samples, but similar analyses have not been done within rural areas. This study analyzes the relationships between reported and substantiated rates of child abuse and county demographic, health care resource and social services factors in a predominantly rural state in the US. METHODS: County-level data from Iowa between 1984-1993 were analyzed for associations between county characteristics and rates of child abuse using univariate correlations and multivariate stagewise regression analysis. Population-adjusted rates of reported and substantiated child abuse were correlated with rates of children in poverty, single-parent families, marriage and divorce, unemployment, high-school dropouts, median family income, elder abuse, birth and death rates, numbers of physicians and other healthcare providers, hospital, social workers, and number of caseworkers in the Department of Human Services. RESULTS: Rates of single-parent families, divorce and elder abuse were significantly associated with reported and substantiated child abuse in multivariate analysis, while economic and most health care factors were not. Reporting and substantiation rates differed across districts after adjustment for multiple factors including caseworker workload. CONCLUSIONS: In this rural state, family structure is more significantly associated with child abuse report and substantiation rates than are socioeconomic factors. The level of health care resources in a county does not appear to affect these rates.     

Complexity leadership in learning analytics: Drivers,challenges and opportunities

Learning analytics (LA) has demonstrated great potential in improving teaching quality, learning experience and administrative efficiency. However, the adoption of LA in higher education is often beset by challenges in areas such as resources, stakeholder buy-in, ethics and privacy. Addressing these challenges in a complex system requires agile leadership that is responsive to pressures in the environment and capable of managing conflicts. This paper examines LA adoption processes among 21 UK higher education institutions using complexity leadership theory as a framework. The data were collected from 23 interviews with institutional leaders and subsequently analysed using a thematic coding scheme. The results showed a number of prominent challenges associated with LA deployment, which lie in the inherent tensions between innovation and operation. These challenges require a new form of leadership to create and nurture an adaptive space in which innovations are supported and ultimately transformed into the mainstream operation of an institution. This paper argues that a complexity leadership model enables higher education to shift towards more fluid and dynamic approaches for LA adoption, thus ensuring its scalability and sustainability.