A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs

Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario.     

Beyond stacking in American football towards an understanding of cultural transmission,social identity and self-categorization

Relying on cultural transmission, social identity and self-categorization theories, this study uses an innovative two-part photo-pasting and survey method to investigate quantitatively and qualitatively non-fans’, fans’ and players’ assumptions about what positions black and white players should occupy in American football. Both white and black players and fans showed evidence of being cultural transmitters of racial ideologies associated with the quarterback position in American football. Overall, the respondent choices for quarterback diverged significantly from equality but not significantly from the reality of the National Football League. Players and fan and non-fan participants alike showed evidence of being cultural consumers and transmitters of racial ideologies associated with the quarterback position. Narrative reasons for player choices aligned with past literature about racial stereotypes. On most measures, the findings did not differ greatly among the institutions from which study participants were drawn, their diversity in geography, racial composition, ideology, athletic division and public–private status notwithstanding.     

The long-term athlete development model: physiological evidence and application

Within the UK, the "Long Term Athlete Development" (LTAD) model has been proposed by a variety of national governing bodies to offer a first step to considering the approach to talent development. The model, which is primarily a physiological perspective, presents an advancement of understanding of developing athletic potential alongside biological growth. It focuses on training to optimize performance longitudinally, and considers sensitive developmental periods known as "windows of opportunity". However, it appears that there are a number of problems with this theoretical model that are not necessarily transparent to coaches. Principally, the model is only one-dimensional, there is a lack of empirical evidence upon which the model is based, and interpretations of the model are restricted because the data on which it is based rely on questionable assumptions and erroneous methodologies. Fundamentally, this is a generic model rather than an individualized plan for athletes. It is crucial that the LTAD model is seen as a "work in progress" and the challenge, particularly for paediatric exercise scientists, is to question, test, and revise the model. It is unlikely that this can be accomplished using classical experimental research methodology but this should not deter practitioners from acquiring valid and reliable evidence.     

Tracking club sport participation from childhood to early adulthood

This study examined the strength of tracking sport participation from childhood to early adulthood among the Dunedin Multidisciplinary Health and Development Study cohort. Participation in sport, dance, or gymnastics as part of a club or group (outside of school) was assessed at ages 7, 9, 15, 18, and 21 years. In addition to the traditionally used correlation coefficients, summary statistics (intraclass correlations; ICC) from random effect models and stability coefficients from generalized estimating equations (GEE) were calculated using all the longitudinal data and controlling for the influence of covariates on tracking strength. Correlation coefficients revealed statistically significant tracking of club sport participation (7-21 years) at low levels (r = .07-0.28). The ICC summary statistic (0.23) was consistent with this, while the GEE suggested moderate tracking (0.59). The results of this study suggest that encouraging sport participation during childhood and adolescence may result in a modest increase in the likelihood of participation later in life. However, the substantial movement into and out of sport participation observed here and in other studies cautions against relying solely on sport promotion among youth as a strategy to promote lifelong participation.     

Increased dietary carbohydrate and endurance during single-leg cycling using a limb with normal muscle glycogen concentration

The purpose of this study was to test the hypothesis that increased availability of blood-borne glucose would improve endurance after carbohydrate loading. A single-leg exercise model was employed, taking advantage of the fact that supercompensation of muscle glycogen occurs only in a previously exercised limb. Endurance time to exhaustion at 70% of maximal oxygen uptake (VO2 max) was determined for 11 males and three females who were then allocated to a control group or a high-carbohydrate (CHO) group. For 3 days following Test 1 the control group maintained a prescribed normal diet whilst the CHO group increased the proportion of energy derived from carbohydrate (62.1 +/- 4.3% cf. 43.9 +/- 2.0%, P less than 0.01). The endurance test was then repeated using the leg that was inactive during Test 1. Endurance time was increased on Test 2 (123.7 +/- 43.2 min cf. 98.5 +/- 21.9 min, P less than 0.05 one-tailed test) for the CHO group but not for the control group (101.8 +/- 21.7 min cf. 107.5 +/- 9.1 min, NS). There was no indication of enhanced carbohydrate metabolism during Test 2 for the CHO group but mean heart rate was lower during Test 2 than during Test 1 (145 +/- 14 beat min-1 cf. 152 +/- 12 beat min-1, P less than 0.05). These results suggest that the prior consumption of a high-carbohydrate diet improves endurance during high-intensity cycling with a limb with normal muscle glycogen concentration.