Association between relative age effect and organisational practices of American youth football.

The popular method of organising youth sport participants into age divisions, based solely on their birthdate, can result in an imbalance of the distribution of players. This is known as relative age effect (RAE), which inadvertently creates bias and is associated with deleterious short and long-term consequences. The overall purpose of this study was to examine how the potential for RAE is mitigated when simultaneously accounting for additional player criterion, supplementary to age.

Multifactorial examination of sex-differences in head injuries and concussions among collegiate soccer players: NCAA ISS, 2004-2009.

Background: While head injuries and concussions are major concerns among soccer players, the multifactorial nature of head injury observations in this group remains relatively undefined. We aim to extend previous analyses and examine sex-differences in the incidence of head injuries, odds of head injuries within an injured sample, and severity of head injuries, among collegiate soccer players between 2004 and 2009.

Methods: Data collected within the National Collegiate Athletic Association (NCAA) Injury Surveillance System (ISS) between the years of 2004 and 2009, were analyzed in this study.

Time Trends in Incidence and Severity of Injury Among Collegiate Soccer Players in the United States: NCAA Injury Surveillance System, 1990-1996 and 2004-2009.

Background: A number of sociocultural and environmental changes have occurred over the past several decades that may affect the risk of injury among young athletes playing soccer.

Purpose: To identify trends in injury incidence and severity between 2 time periods (1990-1996 and 2004-2009) in both male and female National Collegiate Athletic Association (NCAA) soccer players in the United States.

Design: Descriptive epidemiology study.

Time-loss and non-time-loss injuries in youth football players.

Context: Estimates suggest that more than 5.5 million youths play football annually, and 28% of youth football players (age range = 5 to 14 years) are injured each year, resulting in more than 187 000 emergency room visits.

Objective: To analyze time-loss (TL) and non-time-loss (NTL) injury patterns across age groups in youth football players.

Validation of a noninvasive maturity estimate relative to skeletal age in youth football players.

Objective: To validate a non-invasive measure of biological maturity (percentage of predicted mature height at a given age) with an established indicator of maturity [skeletal age (SA)] in youth American football players.

Design: Cross-sectional.

Setting: Two communities in central Michigan.