Workload and non-contact injury incidence in elite football players competing in European leagues

Purpose: The aim of this study was to analyse the relationship between absolute and acute:chronic workload ratios and non-contact injury incidence in professional football players and to assess their predictive ability. Methods: Elite football players (n?=?130) from five teams competing in European domestic and confederation level competitions were followed during one full competitive season. Non-contact injuries were recorded and using session rate of perceived exertion (s-RPE) internal absolute workload and acute:chronic (A:C) workload ratios (4-weeks, 3-weeks, 2-weeks and week-to-week) were calculated using a rolling days method. Results: The relative risk (RR) of non-contact injury was increased (RR?=?1.59, CI95%: 1.18–2.15) when a cumulative 4-week absolute workload was greater than 10629 arbitrary units (AU) in comparison with a workload between 3745 and 10628?AU. When the 3-week absolute workload was more than 8319?AU versus between 2822 and 8318?AU injury risk was also increased (RR=?1.46, CI95% 1.08–1.98). Injury incidence was higher when the 4-week A:C ratio was <0.85 versus >0.85 (RR?=?1.31, CI95%: 1.02–1.70) and with a 3-week A:C ratio >1.30 versus <1.30 (RR?=?1.37, CI95%: 1.05–1.77). Importantly, none of the A:C workload combinations showed high sensitivity or specificity. Conclusions: In elite European footballers, using internal workload (sRPE) revealed that cumulative workloads over 3 and 4 weeks were associated with injury incidence. Additionally, A:C workloads, using combinations of 2, 3 and 4 weeks as the C workloads were also associated with increased injury risk. No A:C workload combination was appropriate to predict injury.     

An analysis of the cultural representation of disability in school textbooks in Iran and England

The paper details the findings of a study which focused on the analysis of the cultural representation of disability in school textbooks in Iran and England. The paper argues that whilst inclusive education could facilitate the incorporating of disabled pupils into mainstream schools, there needs to be deeper examination as to how this transition should take place for children aged 3–13. The paper suggests that in such examinations, school textbooks might be of significance in familiarising non-disabled pupils, teachers and authorities with the issues related to disability and disabled pupils.     

A new method for the measurement and analysis of biomechanical energy delivered by kicking

An accurate measurement of force and biomechanical energy that people can impart through kicking is useful for kick-related sports training. Existing methods are indirect measurements or focus on force and not on the total energy of the kick. A kick test rig was designed, constructed and instrumented to measure the force and displacement of a vertical target subjected to kicking. The kick energy was calculated from the recorded force and displacement histories. The methodology for measurement of kick force and energy was validated by an open stance front kick test by 52 volunteers. The results showed that 67% of the participants could achieve an average energy above 100 J. An increasing trend of kick energy with increasing body weight of participant was observed. The participant’s gender had a strong influence on the kick energy, while training in martial arts does not appear to be a significant parameter. A probability analysis showed that one in one hundred adults will be able to kick with energies exceeding 215 J.     

Leaning towards China: Taiwanese Basketball Talent Migration to the PRC

Abstract

This study aims to examine the different influences on Taiwanese basketball migration from 1999 to the present particularly in relation to the specific political relationship between Taiwan and China. Political influence on sports talent migration is well recognized, but has yet to be fully explored. This study contributes to our understanding of sport migration by providing in-depth empirical and analytical insights into the role of political influences, thereby adding to an understanding of the institutional factors that can either impede or facilitate sport labour migration and of the key networks involved in specific migratory processes.     

Time course of recovery of vertical jump height and heart rate versus running speed after a 90-km foot race

It is well known that sport and exercise play an important role in stimulating site-specific bone mineral density (BMD). However, what is less well understood is how these benefits dissipate throughout the body. Hence, the aim of the present study was to compare the BMD (recorded at nine sites throughout the skeleton) of 106 male athletes (from nine sports) with that of 15 male non-exercising age-matched controls. Given that BMD is known to increase with body mass and peak with age, multivariate and univariate analyses of covariance were performed to compare the BMD of the nine sports groups with controls (at all sites) using body mass and age as covariates. Our results confirmed a greater adjusted BMD in the arms of the upper-body athletes, the right arm of racket players and the legs of runners (compared with controls), supporting the site-specific nature (i.e. specific to the externally loaded site) of the bone remodelling response (all P?<0.01). However, evidence that bone mass acquisition is not just site-specific comes from the results of the rugby players, strength athletes, triathletes and racket players. The rugby players' adjusted BMD was the greatest of all sports groups and greater than controls at all nine sites (all P?<0.01), with differences ranging from 8% greater in the left arm to 21% in the lumbar spine. Similarly, the strength athletes' adjusted BMD was superior to that of controls at all sites (P?<0.05) except the legs. The adjusted BMD of the triathletes was significantly greater than that of the controls in both the arms and the legs as well as the thoracic and lumbar spine. The racket players not only had significantly greater right arm BMD compared with the controls but also a greater BMD of the lumbar spine, the pelvis and legs. In contrast, the low-strain, low-impact activities of keep-fit, cycling and rowing failed to benefit BMD compared with the age-matched controls. These results suggest that sporting activities involving high impact, physical contact and/or rotational forces or strains are likely to convey significant benefits not only to the loaded sites, but also to other unloaded peripheral and axial sites throughout the skeleton.     

Repeatability of scores on a novel test of endurance running performance

Abstract

The aim of the present study was to determine the repeatability of a running endurance test using an automated treadmill system that requires no manual input to control running speed. On three separate occasions, 7 days apart, 10 experienced male endurance-trained runners (mean age 32 years, s = 10; [Vdot]O_2peak 61 ml · kg^?1 · min^?1, s = 7) completed a treadmill time trial, in which they were instructed to run as far as possible in 60 min. The treadmill was instrumented with an ultrasonic feedback-controlled radar modulator that spontaneously regulated treadmill belt speed corresponding to the changing running speed of each runner. Estimated running intensity was 70%[Vdot]O_2peak (s = 11) and the distance covered 13.5 km (s = 2), with no difference in mean performances between trials. The coefficient of variation, estimated using analysis of variance, with participant and trial as main effects, was 1.4%. In summary, the use of an automated treadmill system improved the repeatability of a 60-min treadmill time trial compared with time trials in which speed is controlled manually. The present protocol is a reliable method of assessing endurance performance in endurance-trained runners.     

Choose your primary outcome variables with care

The changes in postural tremor of the hand and the subsequent effect on shooting performance produced by moderate cooling and heating of the forearm were studied in six subjects. Cooling produced a large decrease in tremor size of the ipsilateral hand, whereas warming the limb produced an increase in tremor size. Cooling or warming the forearm did not change the peak frequency of tremor significantly, which was quite stable for each subject. The improvement in shooting performance after cooling the forearm, as measured by grouping pattern of the shots, reached statistical significance and warming caused a significant worsening. This measure of performance was shown to correlate (r = 0.776) inversely with tremor size. The causes and implications of these changes are discussed. It is suggested that local cooling may be useful for people who wish temporarily to reduce tremor in order to improve dexterity for shooting and for other purposes.     

Lacrosse Legends of the First Americans

Abstract

The purpose of this study was to examine the distribution of pace self-selected by cyclists of varying ability, biological age and sex performing in a mountain bike World Championship event. Data were collected on cyclists performing in the Elite Male (ELITE_male; n = 75), Elite Female (ELITE_female; n = 50), Under 23 Male (U23_male; n = 62), Under 23 Female (U23_female; n = 34), Junior Male (JNR_male; n = 71) and Junior Female (JNR_female; n = 30) categories of the 2009 UCI Cross-Country Mountain Bike World Championships. Split times were recorded for the top, middle and bottom 20% of all finishers of each category. Timing splits were positioned to separate the course into technical and non-technical, uphill, downhill and rolling/flat sections. Compared with bottom performers, top performers in all male categories (ELITE_male, U23_male, JNR_male) maintained a more even pace over the event as evidenced by a significantly lower standard deviation and range in average lap speed. Top performers, males, and ELITE_male athletes spent a lower percentage of overall race time on technical uphill sections of the course, compared with middle and bottom placed finishers, females, and JNR_male athletes, respectively. Better male performers adopt a more even distribution of pace throughout cross-country mountain events. Performance of lower placed finishers, females and JNR_male athletes may be improved by enhancing technical uphill cycling ability.     

Effects of Various Knee Angle and Foot Spacing Combinations on Performance in the Vertical Jump

Abstract

Thirty young adult males performed the vertical jump (jump and reach) at knee angles of 65, 90, and 115 degrees while using lateral and anterior-posterior foot spacings of 0, 5, 10, and 15 inches. The preliminary position was held momentarily before jumping, and every subject jumped three times at each of the 48 combinations of knee angles and foot spacings. The average of the three jumps was considered the subject's score for each preliminary stance. The results revealed that: (a) knee angle, lateral foot spacing, and anterior posterior foot spacing exert independent effects on vertical jumping performance; and (b) the most effective preliminary stance seems to be one in which the knee angle is approximately 115° with the feet spread from 5 to 10 inches laterally and slightly in excess of 5 inches anteriorly-posteriorly.