TY - JOUR
T1 - In-Season Variations in Head Impact Exposure among Youth Football Players
AU - Urban, Jillian E.
AU - Kelley, Mireille E.
AU - Espeland, Mark A.
AU - Davenport, Elizabeth M.
AU - Whitlow, Christopher T.
AU - Powers, Alexander K.
AU - Maldjian, Joseph A
AU - Stitzel, Joel D.
N1 - Publisher Copyright:
© Copyright 2019, Mary Ann Liebert, Inc., publishers 2019.
PY - 2019/1/15
Y1 - 2019/1/15
N2 - Head impact exposure (HIE) is often summarized by the total exposure measured during the season and does not indicate how the exposure was accumulated, or how it varied during the season. Therefore, the objective of this study was to compare HIE during pre-season, the first and second halves of the regular season, and playoffs in a sample of youth football players (n = 119, aged 9-13 years). Athletes were divided into one of four exposure groups based on quartiles computed from the distribution of risk-weighted cumulative exposure (RWE CP ). Mean impacts per session and mean 95th percentile linear and rotational acceleration in practices and games were compared across the four exposure groups and time frames using mixed effects models. Within games, the mean 95th percentile accelerations for the entire sample ranged from 47.2g and 2331.3 rad/sec 2 during pre-season to 52.1g and 2533.4 rad/sec 2 during the second half of regular season. Mean impacts per practice increased from pre-season to the second half of regular season and declined into playoffs among all exposure groups; however, the variation between time frames was not greater than two impacts per practice. Time of season had a significant relationship with mean 95th percentile linear and rotational acceleration in games (both, p = 0.01) but not with practice accelerations or impacts per session. The in-practice mean levels of 95th percentile linear and rotational acceleration remained fairly constant across the four time frames, but in games these changed over time depending on exposure group (interactions, p ≤ 0.05). The results of this study improve our understanding of in-season variations in HIE in youth football and may inform important opportunities for future interventions.
AB - Head impact exposure (HIE) is often summarized by the total exposure measured during the season and does not indicate how the exposure was accumulated, or how it varied during the season. Therefore, the objective of this study was to compare HIE during pre-season, the first and second halves of the regular season, and playoffs in a sample of youth football players (n = 119, aged 9-13 years). Athletes were divided into one of four exposure groups based on quartiles computed from the distribution of risk-weighted cumulative exposure (RWE CP ). Mean impacts per session and mean 95th percentile linear and rotational acceleration in practices and games were compared across the four exposure groups and time frames using mixed effects models. Within games, the mean 95th percentile accelerations for the entire sample ranged from 47.2g and 2331.3 rad/sec 2 during pre-season to 52.1g and 2533.4 rad/sec 2 during the second half of regular season. Mean impacts per practice increased from pre-season to the second half of regular season and declined into playoffs among all exposure groups; however, the variation between time frames was not greater than two impacts per practice. Time of season had a significant relationship with mean 95th percentile linear and rotational acceleration in games (both, p = 0.01) but not with practice accelerations or impacts per session. The in-practice mean levels of 95th percentile linear and rotational acceleration remained fairly constant across the four time frames, but in games these changed over time depending on exposure group (interactions, p ≤ 0.05). The results of this study improve our understanding of in-season variations in HIE in youth football and may inform important opportunities for future interventions.
KW - biomechanics
KW - football
KW - head impact exposure
KW - impact magnitude
KW - pediatric
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U2 - 10.1089/neu.2018.5699
DO - 10.1089/neu.2018.5699
M3 - Article
C2 - 29921164
AN - SCOPUS:85059247573
SN - 0897-7151
VL - 36
SP - 275
EP - 281
JO - Journal of neurotrauma
JF - Journal of neurotrauma
IS - 2
ER -