BASES Position Statement on Guidelines for Resistance Exercise in Young People

Abstract

Despite the performance concerns of dehydration in other sports, there are currently no data on the effects of rapid weight-loss on the physical and cognitive performance of jockeys in a sport-specific context. In a randomised crossover design, eight Great Britain (GB) male licensed jockeys were assessed for chest strength, leg strength, simulated riding performance (assessed by maximum pushing frequency on a mechanical riding simulator during the final two furlongs of a simulated 2 mile race) and simple reaction time after performing 45 min of exercise, during which euhydration was maintained (Control trial) or induced 2% dehydration (Rapid Weight-Loss trial). Reductions in both chest (–13.8 ± 3.03% vs. 0.62 ± 1.04%) and leg strength (–4.8 ± 4.8% vs. –0.56 ± 2.5%) were greater in Rapid Weight-Loss compared with Control (P < 0.01 and P = 0.04, respectively). Similarly, reductions in simulated riding performance were also greater (P = 0.05) in Rapid Weight-Loss (–2.8 ± 4.0%) compared with Control (–0.07 ± 1.5%), whereas there were no significant changes (P = 0.14) in simple reaction time. We conclude that a 2% reduction in body mass, as achieved by 45 min of moderate-intensity exercise undertaken in a sweatsuit (a common method of inducing acute dehydration by jockeys), significantly impairs maximum pushing frequency during a simulated race. In addition, the observed reductions in strength may also increase the occupational hazards associated with race riding.     

The effects of work – rest duration on intermittent exercise and subsequent performance

This study examined the effects of different work?–?rest durations during 40?min intermittent treadmill exercise and subsequent running performance. Eight males (mean?±?s: age 24.3?±?2.0 years, body mass 79.4?±?7.0?kg, height 1.77?±?0.05?m) undertook intermittent exercise involving repeated sprints at 120% of the speed at which maximal oxygen uptake (v-[Vdot]O_2max) was attained with passive recovery between each one. The work?–?rest ratio was constant at 1:1.5 with trials involving short (6:9?s), medium (12:18?s) or long (24:36?s) work?–?rest durations. Each trial was followed by a performance run to volitional exhaustion at 150% v-[Vdot]O_2max. After 40?min, mean exercise intensity was greater during the long (68.4?±?9.3%) than the short work?–?rest trial (54.9?±?8.1% [Vdot]O_2max; P?<?0.05). Blood lactate concentration at 10?min was higher in the long and medium than in the short work?–?rest trial (6.1?±?0.8, 5.2?±?0.9, 4.5?±?1.3?mmol?·?l^?1, respectively; P?<?0.05). The respiratory exchange ratio was consistently higher during the long than during the medium and short work?–?rest trials (P <?0.05). Plasma glucose concentration was higher in the long and medium than in the short work?–?rest trial after 40?min of exercise (5.6?±?0.1, 6.6?±?0.2 and 5.3?±?0.5?mmol?·?l^?1, respectively; P?<?0.05). No differences were observed between trials for performance time (72.7?±?14.9, 63.2?±?13.2, 57.6?±?13.5?s for the short, medium and long work?–?rest trial, respectively; P = 0.17), although a relationship between performance time and 40?min plasma glucose was observed (P?<?0.05). The results show that 40?min of intermittent exercise involving long and medium work?–?rest durations elicits greater physiological strain and carbohydrate utilization than the same amount of intermittent exercise undertaken with a short work?–?rest duration.     

The effect of towing a range of relative resistances on sprint performance

The aim of this study was to compare sprint performance over 10 and 20?m when participants ran while towing resistances, weighing between 0 and 30% of body mass. The sample of 33 participants consisted of male rugby and soccer players (age 21.1?±?1.8 years, body mass 83.6?±?13.1?kg, height 1.82?±?0.1?m; mean?±?s). Each participant performed two sets of seven sprints over 20?m using a Latin rectangular design. The times were recorded at 10 and 20?m using electronic speed gates. The sprints of 13 players were video-recorded to allow calculation of stride length and frequency. For both sprints, a quadratic relationship was observed between sprint time and resistance as sprint time increased from 2.94?s to 3.80?s from 0 to 30% resistance. This relationship was statistically significant but considered not to be meaningful for performance because, over the range of resistances used in this study, the quadratic model was never more than 1% (in terms of sprint time) from the linear model. As resistance increased, the stride length shortened, with mean values of 1.63?±?0.13?m at 0% body mass and 1.33?±?0.13?m at 30% of body mass. There was no significant change in stride frequency with increasing resistance. The results show that in general there is an increase in sprint time with an increase in resistance. No particular resistance in the range tested (0?–?30%) can be recommended for practice.     

Self-belief does make a difference: A reciprocal effects model of the causal ordering of physical self-concept and gymnastics performance

Abstract

A large body of research in support of the reciprocal effects model of causal ordering demonstrates that prior academic self-concept predicts subsequent academic achievement beyond what can be explained in terms of prior achievement. Here we evaluate the generalizability of this support for the reciprocal effects model to a physical activity context in which achievement is reflected in gymnastics skills on a standardized gymnastics performance test evaluated by expert judges. Based on the responses of 376 adolescents collected at the start (T1) and end (T2) of a gymnastics training programme, there is support for a reciprocal effects model in which there are significant paths leading from both T1 gymnastics self-concept to T2 gymnastics skills and from T1 gymnastics skills to T2 self-concept. Although there were gender and age effects (girls and older participants had better gymnastics skills, boys had higher self-concepts), multiple group structural equation models indicated that support for the reciprocal effects model generalized over responses by boys and girls. In summary, self-concept and performance are both determinants and consequences of each other.     

Referee bias contributes to home advantage in English Premiership football

Abstract

Officiating bias is thought to contribute to home advantage. Recent research has shown that sports with subjective officiating tend to experience greater home advantage and that referees' decisions can be influenced by crowd noise, but little work has been done to examine whether individual referees vary in their home bias or whether biased decisions contribute to overall home advantage. We develop an ordinal regression model to determine whether various measures of home advantage are affected by the official for the match and by crowd size while controlling for team ability. We examine 5244 English Premier League (EPL) match results involving 50 referees and find that home bias differs between referees. Individual referees give significantly different levels of home advantage, measured as goal differential between the home and away teams, although the significance of this result depends on one referee with a particularly high home advantage (an outlier). Referees vary significantly and robustly in their yellow card and penalty differentials even excluding the outlier. These results confirm that referees are responsible for some of the observed home advantage in the EPL and suggest that home advantage is dependent on the subjective decisions of referees that vary between individuals. We hypothesize that individual referees respond differently to factors such as crowd noise and suggest further research looking at referees' psychological and behavioural responses to biased crowds.     

List of Reviewers

Our purpose was to compare the effect of a periodized preparation consisting of power endurance training and high-intensity power training on the contractile properties of the quadriceps muscle and functional performances in well trained male sprinters (n = 7). After 4 weeks of high-intensity power training, 60-m sprint running time improved by an average of 1.83% (SD = 0.96; p < .05). This improvement was inversely related to an increase in maximal voluntary contraction torque (r = -.89, p < .05) and poorly correlated with changes in the contractile kinetics of the quadriceps muscle (r range from .36 to -.46). These findings suggest that sprint performance is poorly predicted by muscle intrinsic properties and that a neural adaptation appears to explain most of the observed functional adaptations.     

Trends in the Selection of Coaches for Female Athletes: A Demographic Inquiry

Abstract

Data were collected from 335 collegiate female athletic directors utilizing a questionnaire designed to assess trends in selecting coaches for female athletes between 1974 and 1979. These demographic results revealed: (a) a 37% increase in the number of coaches for female athletes, (b) a greater increase at the assistant (229%) rather than head (8%) coach level, (c) a substantial increase in male coaches (724) in comparison to their female counterparts (44), (d) a significant decline (294) in female head coaches, and (e) a large increase in the number of male head coaches (437). As the bases for this present investigation, current practices and affirmative action strategies were discussed (i.e., gender employment trends, de facto discrimination, federal civil rights legislation). Possible explanations of these findings were offered.     

Influence of Decision-Making on Attitudes,Creativity, Motor Skills and Self-Concept in Elementary Children

Abstract

Attitudes, creativity, self-concept and motor skills were measured to determine the influence of decision-making on elementary children. Three groups of children (N = 208) were tested, one group was taught with the teacher dominating all classroom decisions, another group was encouraged to share in the decision-making, and a third group served as a control. Data were collected immediately before and after an eight-week instructional period. MANCOVA indicated that the two treatment groups had significantly higher scores than did the control group, and the shared decision-making group scored significantly higher than the teacher dominated group on measures of creativity, motor skills and self-concept. A 2 (treatment) × 2 (sex) × 5 (grade) ANOVA revealed significantly more positive attitude scores for children allowed to make decisions regarding their learning. Further, Pearson product-moment correlation showed the tested variables to be independent measures of a child's development.