Biomechanical Properties of Concussions in High School Football

Abstract

INTRODUCTION Sport concussion represents the majority of brain injuries occurring in the United States with 1.6 to 3.8 million cases annually. Understanding the biomechanical properties of this injury will support the development of better diagnostics and preventative techniques. METHODS We monitored all football related head impacts in 78 high school athletes (mean age 16.7 years) from 2005 through 2008 in order to better understand the biomechanical characteristics of concussive impacts. RESULTS Using the Head Impact Telemetry System (HITS), a total of 54,247 impacts were recorded and 13 concussive episodes captured for analysis. A classification and regression tree (CART) analysis of impacts indicated that rotational acceleration (>5582.3 rad/s2), linear acceleration (>96.1 g), and impact location (front, top, back) yielded the highest predictive value of concussion. CONCLUSIONS These threshold values are nearly identical to those reported at the collegiate and professional level. If the HITS were implemented for medical use, sideline personnel can expect to diagnose one of every five athletes with a concussion when the impact exceeds these tolerance levels. Why all athletes did not sustain a concussion when the impacts generated variables in excess of our threshold criteria is not entirely clear, although individual differences between participants may play a role. A similar threshold to concussion in adolescent athletes compared to their collegiate and professional counterparts suggests an equal concussion risk at all levels of play.

Head-Impact–Measurement Devices: A Systematic Review

“…Collegiate football athletes sustained 420 to 1177 impacts, 48,55 with 9.4 impacts per session 49 at a median linear magnitude of 19g 50 and average 73 Linear magnitudes averaged 26g, 71 with a median of 22g. 74 Angular magnitudes averaged 71,72 1627 to 1694 rad/s 2 and had a median value 74 of 973 rad/s 2 .…”

“…7 g t o 145g, 16,17,47,58,61,62,70,72 with a 95th percentile of 7688 rad/ s 2 . 26 Among football injuries, acceleration and impact location increased the specificity of injury prediction.…”

“…26 Among football injuries, acceleration and impact location increased the specificity of injury prediction. 40,72 A total of 6 collegiate ice hockey concussions were captured using the HITS. Linear values ranged from 30.7g to 31.7g in an all-male sample 61,62 (n ¼ 2) and 30.4g to 52.2g in an all-female sample 43 (n ¼ 4).…”

The Influence of Head Impact Threshold for Reporting Data in Contact and Collision Sports: Systematic Review and Original Data Analysis

“…Based on the differences observed in this study, at the 14.4g threshold there could have been as many as 42% of the impacts recorded not being reported. As a result, studies 7,8,[12][13][14][15]20, 27, 33, 94, 107, 115, 119 using impact thresholds above 10g may have removed 2,100 to 206,573 impacts (see Table 2). At the 30g impact threshold it can be estimated that 80 to 85% of impacts were not reported.…”

Sub-Concussive Hit Characteristics Predict Deviant Brain Metabolism in Football Athletes

“…All athletes were also monitored for head collision events using the Head Impact Telemetry System (HITS; Simbex; Lebanon, NH), a sideline data collection system that reports the time, location, and magnitude of head impacts experienced by athletes. The HIT System has been employed in a number of studies of football-related neurotrauma (Broglio et al, 2010;Crisco et al, 2011;Talavage et al, 2014).…”