Related Experiment Video
Updated: May 28, 2026

A Test Bed to Examine Helmet Fit and Retention and Biomechanical Measures of Head and Neck Injury in Simulated Impact
Published on: September 21, 2017
The effect of play type and collision closing distance on head impact biomechanics
Karen E Ocwieja1, Jason P Mihalik, Stephen W Marshall
1Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, 2207 Stallings-Evans Sports Medicine Complex, Campus Box 8700, Chapel Hill, NC 27599-8700, USA.
Abstract:
Football accounts for 55% of concussions to collegiate athletes. In the National Football League, players are at a greater risk for concussion during kickoffs and punts compared to rushing and passing plays. The two primary purposes of this study were to determine if game-related special teams head impacts were greater in magnitude than head impacts sustained during offensive and defensive plays, and to better understand the effect closing distance between players (short vs. long) had on head impact magnitude. Collegiate football players were enrolled in a prospective cohort study assessing head impact biomechanics during special teams, offensive, and defensive collisions; long closing distance (≥ 10 yards) and short closing distance (<10 yards) impacts were also studied. Data were analyzed using random intercepts general linear mixed models. Long closing distance collisions generated more severe head impacts than short closing distances. Collisions occurring on special teams plays over long closing distances were most severe while collisions occurring on special teams and defensive plays over short closing distances resulted in the least severe impacts. Decreasing the impact severity of collisions in collegiate football may be accomplished by reducing the closing distance prior to impact.
Related Concept Videos
Types of Collisions - II
Types of Impact
The coefficient of restitution is a metric for understanding the dynamics of impacts. It quantifies the ratio of relative velocity...
Impact
When particles with different initial velocities collide, they induce deformation by applying equal and opposite impulses. At the point of maximum deformation, the particles move together with...
Types Of Collisions - I
Elastic Collisions: Case Study
Impact: Problem Solving
By designating the launch point as the origin and utilizing kinematic equations, the vertical component of the projectile's velocity at the point of impact is...
