The relationship between peak height velocity and physical performance in youth soccer players

Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.     

Comfort assessment of running footwear: Does assessment type affect inter-session reliability?

Assessing comfort of running footwear reliably is challenging. The purpose of this study was to compare the intra-rater reliability between different assessment types, to calculate intra-individual reliability scores and to evaluate the effect of rater selection based on individual reliability scores on group level reliability. Three assessment types: ranking, Visual Analogue Scale (VAS), and Likert Scale (LS) were provided twice in six separate sessions among 30 participants, who assessed comfort of five shoes after treadmill running. Spearman's rho provided an evaluation of inter-session relative reliability and typical error as a measure of absolute reliability for each assessment type. Ranking (r?=?0.70, 95% confidence interval [CI] 0.61–0.78) yielded the highest relative reliability for overall comfort, followed by VAS (r?=?0.67, 95% CI 0.56–0.75) and LS (r?=?0.63, 95% CI 0.52–0.72), with large-scale overlaps of CIs between assessment types. The same order of assessment types was found for the percentage of reliable raters (r?≥?0.7) with 60% in ranking scale, 47% in VAS and 37% in LS. Forming subgroups corresponding to the intra-individual reliability substantially increased group level reliabilities. Based on measures of relative reliability, an extreme reduction in resolution as provided by the ranking from pairwise comparisons seems to be a valuable tool in footwear comfort assessments if assessment time is of minor importance. No preference can be provided for the two investigated rating scales. Besides the assessment type, a selection of the best raters in additional reliability checks seems to be a prerequisite for further comfort-related studies.     

Lessons learned and tables turned: ‘(in)security’ and media representations in the 2018 World Cup

ABSTRACT

This essay follows up on an article published in Soccer & Society prior to the 2018 World Cup in Russia. There it was argued that this edition of the World Cup served as particularly interesting for the academic field focussed on sport-mega events (SMEs) and ‘security’, because of its uniquely securitized climate. Written immediately after the 2018 World Cup, the present essay reflects upon the event’s ‘security’ and mega-event security more broadly. It revisits some ‘security-related’ episodes. Then, special attention will be given the media discourse vis-à-vis ‘hooliganism’. The essay argues that the media discourse took an unorthodox ‘turn’ with regard to English ‘hooligans’, who, compared to past events, were portrayed as being ‘in risk’ – rather than being the group generating ‘the risk’ of football-related violence and public disorder.     

Leg amputation side determines performance in curve sprinting: a case study on a Paralympic medalist

The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level.     

Indirekte Gesundheitseffekte des Unterrichtsprogramms HealthyPEP

Numerous studies have confirmed direct health effects of interventions with a physical activity component on students without providing sufficient information on the contents or the degree to which the programs have been carried out. The empirical evidence of the indirect health effects of physical education is weaker. In this article the focus is placed on the evaluation of the indirect health effects, such as the enhancement of physical activity and its psychological determinants (e.g. motivation, attitudes, self-efficacy and knowledge) of the health promotion program HealthyPEP, using a quasi-experimental design with 516 sixth grade students. When taking into account the contents of HealthyPEP and the degree of implementation, it was clear that the program had different effects on the two genders whereby girls evaluated HealthyPEP in a more positive way compared to boys. In girls, positive tendencies were observed on rational cognitive determinants (e.g. knowledge and attitudes towards sports). The contents of HealthyPEP must be further optimized in the future to achieve positive indirect health effects also on boys.