Thermal insulation and evaporative resistance of football uniforms

Abstract

Purpose: To measure the thermal resistance (R(t)) and evaporative resistance (R(e,t)) of five different configurations of football uniforms commonly worn for American football practices and games.

Methods: The R(t) (insulation) of the ensembles was measured using an electrically heated manikin in thermal equilibrium with its surroundings. For the R(e,t) determinations, the manikin was covered with a cotton knit "skin" and sprayed with distilled water to simulate sweat-saturated skin.

Results: Compared with reference values for a T-shirt and shorts ensemble (R(t) = 0.140 m2. degrees C.W-1, R(e,t) = 0.020 m2.kPa-1.W-1), the R(t) of football uniforms ranged from 0.178 m2. degrees C.W-1 (1.15 clo) for a practice configuration of shorts, shoulder pads, practice jersey, and helmet to 0.233 m2. degrees C.W-1 (1.50 clo) for a full cold-weather uniform. Associated R(e,t) values ranged from 0.027 to 0.039 m2.kPa-1.W-1.

Conclusion: Football uniforms contribute significantly to the heat load on a player. The thermal and evaporative resistance data presented in this paper can be used in the solution of heat balance equations to predict physiological responses of football players.