A review of laboratory methods and results used to evaluate protective headgear in American football

Abstract

As head trauma becomes more firmly associated with American football, research has focused on improving the impact performance of protective headgear. Since helmet use became mandatory in 1939–1940, both helmet design and laboratory methods used to evaluate helmet impact performance have evolved. Through a comprehensive review of the literature, this article analyzes the impact results from laboratory evaluations of helmet performance, including a look at the evolution of protective headgear performance in football. In total, 35 separate studies conducted between 1975 and 2017 were used to examine current testing methodologies and reported impact results from headgear performance laboratory assessments. This review showed that the evolution in helmet design over the last 50 years has resulted in a decrease in linear and rotational acceleration of an impacted headform. The most common laboratory methods used to reconstruct football-specific head impacts included (1) linear drop methods, (2) pendulum methods, and (3) pneumatic ram methods. Each method provided greater understanding of helmet impact performance, helmet design, and use in football, with each method having specific limitations in the evaluation of protective headgear performance.