Thermal insulation and evaporative resistance of football uniforms

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.

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.

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.

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.