Open AccessSubconcussive head impact exposure between drill intensities in U.S. high school football
Author(s) -
Kyle A. Kercher,
Jesse A. Steinfeldt,
Jonathan T. Macy,
Keisuke Ejima,
Keisuke Kawata
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0237800
Subject(s) - football , head (geology) , mouthguard , american football , drill , zoology , football players , demography , medicine , environmental science , physical therapy , materials science , geography , biology , archaeology , paleontology , sociology , metallurgy
USA Football established five levels-of-contact to guide the intensity of high school football practices. The objective of this study was to examine head impact frequency and magnitude by levels-of-contact to determine which drills had the greatest head impact exposure. Our primary hypothesis was that there would be an incremental increase in season-long head impact exposure between levels-of-contact: air < bags < control < thud < live . This observational study included 24 high-school football players during all 46 practices, 1 scrimmage, 9 junior varsity and 10 varsity games in the 2019 season. Players wore a sensor-installed mouthguard that monitored head impact frequency, peak linear acceleration (PLA), and rotational acceleration (PRA). Practice/game drills were filmed and categorized into five levels-of-contact ( air , bags , control , thud , live ), and head impact data were assigned into one of five levels-of-contact. Player position was categorized into lineman, hybrid, and skill. A total of 6016 head impacts were recorded during 5 levels-of-contact throughout the season. In the overall sample, total number of impacts, sum of PLA, and PRA per player increased in a near incremental manner ( air < bag s100 g ) head impacts were more frequently observed during live and thud drills. Level-of-contact influences cumulative head impact frequency and magnitude in high-school football, with players incurring frequent, high magnitude head impacts during live , thud , and control . It is important to consider level-of-contact to refine clinical exposure guidelines to minimize head impact burden in high-school football.