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Concept: Players at the Game of People


OBJECTIVE Even in the absence of a clinically diagnosed concussion, research suggests that neurocognitive changes may develop in football players as a result of frequent head impacts that occur during football games and practices. The objectives of this study were to determine the specific situations in which high-magnitude impacts (accelerations exceeding 40 g) occur in youth football games and practices and to assess how representative practice activities are of games with regard to high-magnitude head impact exposure. METHODS A total of 45 players (mean age 10.7 ± 1.1 years) on 2 youth teams (Juniors [mean age 9.9 ± 0.6 years; mean body mass 38.9 ± 9.9 kg] and Seniors [mean age 11.9 ± 0.6 years; mean body mass 51.4 ± 11.8 kg]) wore helmets instrumented with accelerometer arrays to record head impact accelerations for all practices and games. Video recordings from practices and games were used to verify all high-magnitude head impacts, identify specific impact characteristics, and determine the amount of time spent in each activity. RESULTS A total of 7590 impacts were recorded, of which 571 resulted in high-magnitude head impact accelerations exceeding 40 g (8%). Impacts were characterized based on the position played by the team member who received the impact, the part of the field where the impact occurred, whether the impact occurred during a game or practice play, and the cause of the impact. High-magnitude impacts occurred most frequently in the open field in both games (59.4%) and practices (67.5%). “Back” position players experienced a greater proportion of high-magnitude head impacts than players at other positions. The 2 teams in this study structured their practice sessions similarly with respect to time spent in each drill, but impact rates differed for each drill between the teams. CONCLUSIONS High-magnitude head impact exposure in games and practice drills was quantified and used as the basis for comparison of exposure in the 2 settings. In this cohort, game impact rates exceeded those for practice. Back players, who were often positioned in the open field, were shown to experience elevated levels of head impact exposure relative to players at other positions. The analysis also suggests that practice intensity, which may be influenced by coaching style, may also affect high-magnitude head impact exposure. Future studies should investigate this aspect as a factor affecting head impact exposure.

Concepts: Mass, Best practice, American football, Team, Game, 2000s American television series, Football, Players at the Game of People


Pokémon GO is the most played augmented reality game in history. With more than 44 million players at the peak of its popularity, the game has sparked interest on its effects on the young population’s health.

Concepts: Mind, Simulated reality, Virtual reality, Player, Augmented reality, Players at the Game of People



The 2011 English Elite Player Performance Plan (EPPP) stipulates training volumes that could put elite youth players at high risk of non-functional overreaching. The aim of the study was to assess player perceptions of well-being and physical performance to these high training loads. Fourteen academy football players (mean ± SD: age 17 ± 1 years; stature 179 ± 6 cm; body mass 70.8 ± 8.6 kg, at pre-season) completed a perception of well-being questionnaire 1-4 times per week throughout each training block (pre-season, in-season 1, 2, 3). Physical performance tests were carried out at the end of each training block. Increases in training exposure (P < 0.05; [Formula: see text] = 0.52) and moderate to large deteriorations in perceptions of well-being (motivation, sleep quality, recovery, appetite, fatigue, stress, muscle soreness P < 0.05; [Formula: see text] = 0.30-0.53) were evident as the season progressed. A moderate decrease in 30 m sprint performance (P < 0.05; [Formula: see text] = 0.48), a large improvement in Yo-Yo intermittent recovery test performance (P < 0.05; [Formula: see text] = 0.93) and small decreases in countermovement jump (P > 0.05; [Formula: see text] = 0.18) and arrowhead agility (P < 0.05; [Formula: see text] = 0.24) performance were evident as the season progressed. The present findings show an imbalance between stress and recovery in English elite youth players even when players experience lower training exposure than stipulated by the EPPP.

Concepts: Volume, Perception, Mind, Players, Player, Players at the Game of People


Like many sports in adolescence, junior hockey is organized by age groups. Typically, players born after December 31st are placed in the subsequent age cohort and as a result, will have an age advantage over those players born closer to the end of the year. While this relative age effect (RAE) has been well-established in junior hockey and other professional sports, the long-term impact of this phenomenon is not well understood. Using roster data on North American National Hockey League (NHL) players from the 2008-2009 season to the 2015-2016 season, we document a RAE reversal-players born in the last quarter of the year (October-December) score more and command higher salaries than those born in the first quarter of the year. This reversal is even more pronounced among the NHL “elite.” We find that among players in the 90th percentile of scoring, those born in the last quarter of the year score about 9 more points per season than those born in the first quarter. Likewise, elite players in the 90th percentile of salary who are born in the last quarter of the year earn 51% more pay than players born at the start of the year. Surprisingly, compared to players at the lower end of the performance distribution, the RAE reversal is about three to four times greater among elite players.

Concepts: Cohort study, Ice hockey, 2000s American television series, National Hockey League, Salary, Players at the Game of People


The epidemiology of football-related concussions has been extensively examined. However, although football players experience more at-risk exposure time during practices than competitions, there is a dearth of literature examining the nature of the activities or equipment worn during practice. In particular, varying levels of equipment worn during practices may place players at varying levels of risk for concussion.

Concepts: Premier League, The Football League, Concussion, Shutter speed, La Liga, Players at the Game of People, Oldham Athletic A.F.C.


Asymmetry is a risk factor for male youth soccer players. There is a paucity of data confirming the presence of asymmetry using practically viable screening tasks in players at different stages of maturation.

Concepts: Players at the Game of People


This study assessed the contribution of relative age, anthropometry, maturation, and physical fitness characteristics on soccer playing position (goalkeeper [GK], central-defender [CD], lateral-defender [LD], central-midfield [CM], lateral-midfielder [LM], and forward [FWD]) for 465 elite-youth players (U13-U18’s). U13-14 CD were relatively older than LD and CM (likely small effects). CD and GK were generally taller and heavier (likely small to very-likely moderate effects) than other players at each developmental stage and were advanced maturers at U13-14 (very-likely small to likely moderate effects). GK had inferior agility (very-likely small to likely moderate effects), endurance (very-likely small to likely moderate effects), and sprint capacities (likely small-moderate effects) vs. outfield positions at U13-14, but deficits in anaerobic phenotypes were diminished in U15-16 and U17-18. Position specific fitness characteristics were distinguished at U15-16 (likely small) and U17-18 (likely moderate), where LM were faster than their central counterparts. In summary, relative age, maturation and anthropometric characteristics appear to bias the allocation of players into key defensive roles from an early development stage, whereas position-specific physical attributes do not become apparent until the latter stages of talent development in outfield players. Given the inter-individual trajectories of physical development according to biological maturation, playing position allocation might be considered ‘plastic’ by selectors, until complete-maturity is achieved.

Concepts: Anthropometry, Relative, Developmental psychology, Attribute, Players at the Game of People


Soccer is played by more than 250 million people worldwide. Repeatedly heading the ball may place soccer players at high risk for repetitive subconcussive head impacts (RSHI). This study evaluates the long-term effects of RSHI on neurochemistry in athletes without a history of clinically diagnosed concussion, but with a high exposure to RSHI. Eleven former professional soccer players (mean age 52.0 ± 6.8 years) and a comparison cohort of fourteen age- and gender-matched former non-contact sport athletes (mean age 46.9 ± 7.9 years) underwent 3T magnetic resonance spectroscopy (MRS) and neurocognitive evaluation. In the soccer players a significant increase was observed in both, choline, a membrane marker, and myo-inositol, a marker of glial activation, compared to control athletes. Additionally, myo-inositol and glutathione were significantly correlated with lifetime estimate of RSHI within the soccer group. There was no significant difference in neurocognitive tests between groups. Results of this study suggest an association between RSHI in soccer players and MRS markers of neuroinflammation, suggesting that even subconcussive head impacts affect the neurochemistry of the brain and may precede neurocognitive changes. Future studies will need to determine the role of neuroinflammation in RSHI and the effect on neurocognitive function.

Concepts: Brain, Effect, Statistical significance, Nuclear magnetic resonance, Magnetic resonance imaging, Marker, In vivo magnetic resonance spectroscopy, Players at the Game of People


Soccer is the source of the highest concussion rates among female athletes and is associated with neurological deficits at many levels of play. Despite its importance to our understanding of head trauma in female athletes, little is known about the number and magnitude of head impacts experienced by female soccer players. Head impacts experienced by high school and collegiate athletes were quantified using xPatch sensors (X2 Biosystems) affixed behind the right ear of each player. The average peak translational acceleration (PTA) sustained by players at the high school level was significantly lower than that of the collegiate players, but the average peak angular accelerations (PAA) were not significantly different. Given that the collegiate players took many more impacts throughout the season, their mean cumulative exposure to translational (cPTA) and angular accelerations (cPAA) were significantly higher than those of the high school players. Additional research is required to determine whether the differences in cumulative exposure are responsible for the elevated risk of concussion in collegiate soccer players or if there are additional risk factors.

Concepts: High school, Knowledge, Acceleration, College, Player, Players at the Game of People