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Objectives: To investigate and evaluate the methodological variation in research on acute:chronic workload ratio (ACWR) and injury in elite male football players. Methods: Relevant literature was electronically searched on PubMed, Web of Science, ScienceDirect, and Embase. Additional literature was obtained from studies' bibliographies and authors. Cohort studies investigating the effects of ACWR on male elite footballer injuries were included. Information regarding study population, time frame, protocol, injury classification, and statistical analysis were elucidated. Results: Database searches led to 2,689 articles. After full text screening, twelve articles remained. All studies were of poor quality. Five studies had GPS-derived workload measures with consideration of running intensity zones, though little consensus over zone thresholds were found. Nine studies incorporated rated perceived exertion data; heterogeneity in exposure type and data collection timing was observed. All studies applied rolling average ACWRs, exploring 1:2, 1:3, and 1:4-week load ratio windows. Differences in data grouping, inference or regression analysis, and other statistical methods were noted. Conclusion: Existing literature displayed methodological heterogeneity. Future studies should consider consulting guidelines for developing prognostic studies and further examine causal links between workload and injury. From that basis, decisions around ACWR definitions, workload measures, and statistical methods may be more appropriately made. [ABSTRACT FROM AUTHOR]

In a context of morphological expansion of the general population, how do athletes follow such a pattern of anthropometric growth? Is there any relation to performance? Biometric data including mass, height, body mass index (BMI) and age were collected for 50,376 American athletes representing 249,336 annual performers playing in professional baseball, football, ice hockey and basketball. Distributions by mass in National Football League (NFL) players are described by periods. Field goals have been studied in relation to players’ height in the National Basketball Association (NBA). Between 1871 and 2011, athletes from the four sports have increased significantly in mass, height and BMI, following a multi-exponential function series. Consequently, biometric differences between athletes and the general population are increasing gradually. Changes in the mass distribution within the NFL show the emergence of a biometrical specificity in relation to the field position. At the professional level, performance remains structured around precise biometric values. In the NBA, a height-attractor at 201.3 ± 6.3 cm for the best scorers is invariant, regardless of the level of play. These results suggest that laws of growth and biometrics drive high-level sport and organise performance around the specific constraint of each field position. Discrepancies between some mass and height developments question the (disproportionate) large mass increase (relative to the height increase) during the 1980s and 1990s. [ABSTRACT FROM AUTHOR]

As opposed to many other track-and-field events, marathon performances still improve. We choose to better describe the reasons for such a progression. The 100 best marathon runners archived from January 1990 to December 2011 for men and from January 1996 to December 2011 for women were analysed. We determined the impact of historical, demographic, physiological, seasonal and environmental factors. Performances in marathons improve at every level of performance (deciles). In 2011, 94% of the 100 best men athletes were African runners; among women athletes they were 52%. Morphological indicators (stature, body mass and Body Mass Index (BMI)) have decreased. We show a parabolic function between BMI and running speed. The seasonal distribution has two peaks, in spring (weeks 14 to 17) and autumn (weeks 41 to 44). During both periods, the average temperature of the host cities varies close to optimal value for long distance race. African men and women runners are increasingly dominating the marathon and pushing its record, through optimal eco-physiological conditions. [ABSTRACT FROM PUBLISHER]

Road cycling ranks among the most intense endurance exercises. Previous studies and mathematical models describing road cycling have not analysed performances per se. We describe the evolution of road cycling performance over the past 116 years. We studied the top ten cyclists' mean speeds in eight famous classic races and three European Grand Tours, using a previously published multi-exponential model that highlights the different progression periods of an event during the century. In addition, we measured an indicator of difficulty for the Tour de France by calculating the climbing index (i.e. the total altitude climbed over total distance). The eleven races' mean speed increased progressively from 23.13 km · h-1 in 1892 to 41.19 ± 2.03 km · h-1 in 2008. Road cycling development, like other quantifiable disciplines, fits a piecewise progression pattern that follows three periods: before, between, and after the two World Wars. However, a fourth period begins after 1993, providing a speed progression of 6.38% from the third one. The Tour de France's climbing index also provided insight into a recent paradoxical relationship with speeds: when the climbing index increased, the winner's speed also increased. Our results show a major improvement (6.38%) in road cycling performance in the last 20 years and question the role of extra-physiological parameters in this recent progression. [ABSTRACT FROM AUTHOR]