Do oarsmen have asymmetries in the strength of their back and leg muscles?

The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen.     

Season-of-birth bias in association football

In this longitudinal study, we assessed the frequency of birth dates for boys selected for the Football Association National School. Birthdays were divided into three periods of the year: January to April, May to August and September to December. We compared data over a 5 year period and concluded that there is indeed a bias towards selecting older children. Furthermore, analysis of separate data revealed a shift of bias when comparing two different start dates, namely September and January. Our findings show that the youngest children from the January start date (born September to December) are selected significantly more often than the youngest children from the September start date (born May to August). Interestingly, even when the influence of body mass was reduced, the selection bias towards the older players remained.     

Effects of active, passive or no warm-up on metabolism and performance during high-intensity exercise

The aim of this study was to determine the influence of type of warm-up on metabolism and performance during high-intensity exercise. Eight males performed 30 s of intense exercise at 120% of their maximal power output followed, 1 min later, by a performance cycle to exhaustion, again at 120% of maximal power output. Exercise was preceded by active, passive or no warm-up (control). Muscle temperature, immediately before exercise, was significantly elevated after active and passive warm-ups compared to the control condition (36.9 +/- 0.18 degrees C, 36.8 +/- 0.18 degrees C and 33.6 +/- 0.25 degrees C respectively; mean +/- sx) (P< 0.05). Total oxygen consumption during the 30 s exercise bout was significantly greater in the active and passive warm-up trials than in the control trial (1017 +/- 22, 943 +/- 53 and 838 +/- 45 ml O2 respectively). Active warm-up resulted in a blunted blood lactate response during high-intensity exercise compared to the passive and control trials (change = 5.53 +/- 0.52, 8.09 +/- 0.57 and 7.90 +/- 0.38 mmol x l(-1) respectively) (P < 0.05). There was no difference in exercise time to exhaustion between the active, passive and control trials (43.9 +/- 4.1, 48.3 +/- 2.7 and 46.9 +/- 6.2 s respectively) (P= 0.69). These results indicate that, although the mechanism by which muscle temperature is elevated influences certain metabolic responses during subsequent high-intensity exercise, cycling performance is not significantly affected.     

The influence of self-efficacy and past behaviour on the physical activity intentions of young people

The aim of the present study was to assess the influence of self-efficacy and past behaviour on young people's physical activity intentions using an augmented version of Ajzen's Theory of Planned Behaviour. We hypothesized that self-efficacy would exhibit discriminant validity with perceived behavioural control and explain unique variance in young people's intentions to participate in physical activity. We also expected that past physical activity behaviour would attenuate the influence of attitude, subjective norms, perceived behavioural control and self-efficacy on intention. The sample comprised 1,152 young people aged 13.5 +/- 0.6 years (mean +/- s) who completed inventories assessing their physical activity intentions, attitudes, subjective norms, perceived behavioural control, self-efficacy and past physical activity behaviour. A confirmatory factor analysis demonstrated that the constructs of the Theory of Planned Behaviour achieved discriminant validity. Furthermore, the measures of attitudes, subjective norms, perceived behavioural control and self-efficacy were significantly related to their respective belief-based measures, supporting the concurrent validity of the measures of the Theory of Planned Behaviour. A non-standard structural equation model demonstrated that attitude and self-efficacy were strong predictors of physical activity intention, but perceived behavioural control and subjective norms were not. Self-efficacy attenuated the influence of attitudes and perceived behavioural control on intention. Past behaviour predicted intention directly and indirectly through self-efficacy and attitude. The present findings demonstrate that young people with positive attitudes and high self-efficacy are more likely to form intentions to participate in physical activity. Furthermore, controlling for past physical activity behaviour revealed that the unique effects of self-efficacy and attitudes on young people's physical activity intentions were unaltered.     

Impact forces and neck muscle activity in heading by collegiate female soccer players

Three soccer header types (shooting, clearing and passing) and two heading approaches (standing and jumping) were manipulated to quantify impact forces and neck muscle activity in elite female soccer players. The 15 participants were Division I intercollegiate soccer players. Impact forces were measured by a 15-sensor pressure array secured on the forehead. The electromyographic (EMG) activity of the left and right sternocleidomastoid and trapezius muscles was recorded using surface electrodes. Maximum impact forces and impulses as well as the EMG data were analysed with separate repeated-measures analyses of variance. Impact forces and impulses did not differ among the header types or approaches. Higher values were found for jumping versus standing headers in the mean normalized EMG for the right sternocleidomastoid. In addition, the integrated EMG was greater for the right sternocleidomastoid and right and left trapezius (P < 0.05). The sternocleidomastoid became active earlier than the trapezius and showed greater activity before ball contact. The trapezius became active just before ball contact and showed greater activity after ball contact. The increased muscle activity observed in the neck during the jumping approach appears to stabilize the connection between the head and body, thereby increasing the stability of the head-neck complex.     

Information--movement coupling: implications for the organization of research and practice during acquisition of self-paced extrinsic timing skills

Information--movement coupling is a fundamental concept, integral to theorizing on the coordination of goal-directed activity in ecological psychology. In this paper, we examine the implications of this concept for the design of experimental research and the organization of practice during the acquisition of movement coordination in sport tasks. The task vehicle for our analysis is interceptive actions, in particular self-paced extrinsic timing tasks exemplified by serving in sports such as volleyball. Recent research highlighting the relevance of information--movement coupling for the process of practice in sport is discussed. We conclude that information--movement coupling represents an important principle for the structural organization of research and practice in self-paced extrinsic timing tasks and that further work is required to verify its significance across a range of sport movements.     

Statistical analyses in the physiology of exercise and kinanthropometry

Research into the physiology of exercise and kinanthropometry is intended to improve our understanding of how the body responds and adapts to exercise. If such studies are to be meaningful, they have to be well designed and analysed. Advances in personal computing have made available statistical analyses that were previously the preserve of elaborate mainframe systems and have increased opportunities for investigation. However, the ease with which analyses can be performed can mask underlying philosophical and epistemological shortcomings. The aim of this review is to examine the use of four techniques that are especially relevant to physiological studies: (1) bivariate correlation and linear and non-linear regression, (2) multiple regression, (3) repeated-measures analysis of variance and (4) multi-level modelling. The importance of adhering to underlying statistical assumptions is emphasized and ways to accommodate violations of these assumptions are identified.     

Research methods in sport and exercise psychology: quantitative and qualitative issues

Contemporary aspects of research methods in sport and exercise psychology are discussed in this wide-ranging review. After an introduction centred on trends in sport and exercise psychology methods, the review is organized around the major themes of quantitative and qualitative research. Our aim is to highlight areas that may be problematic or controversial (e.g. stepwise statistical procedures), underused (e.g. discriminant analysis), increasingly used (e.g. meta-analysis, structural equation modelling, qualitative content analysis) and emergent (e.g. realist tales of writing). Perspectives range from the technical and speculative to the controversial and critical. While deliberately not providing a 'cookbook' approach to research methods, we hope to provide enough material to help researchers to appreciate the diversity of potential methods and to adopt a more critical perspective in their own research consumption and production.     

The most important points in grand slam singles tennis

A computerized data management system was used to enter details of points played in 252 tennis matches from the men's and women's singles events of all four Grand Slam tournaments over a 2-year period. A supplementary data analysis system was developed to determine the proportion of points won by each player on serve at each game score from love all to deuce as well as the proportion of games the player went on to win from each score. Analysis of the 43 matches in which both players served at each score from love all to deuce revealed that the proportion of points won by the server was not significantly influenced by score, F(15, 495) = 0.8, p > .05. A further analysis of the 175 matches consisting of at least 100 points revealed that the proportion of points won by the superior player was not significantly influenced by gender, F(1, 165) = 0.1, p > .05, or surface, F(3, 165) = 0.1, p > .05. However, the proportion of points won when serving was significantly greater in men's singles than women's singles, F(1, 165) = 69.7, p < .001, R2 = .30. Surface also had a significant influence on the proportion of points won when serving, F(3, 165) = 8.1, p < .001, R2 = .13, with a significantly greater proportion of points won when serving by both winning and losing players at Wimbledon than at the Australian and French Opens, p < .05. This suggests that gender and surface should be accounted for when determining the importance of points in Grand Slam tennis.