This prospective study was conducted to determine whether hip muscle strength and flexibility play a role in the incidence of adductor and hip flexor strains in National Hockey League ice hockey team players. Hip flexion, abduction, and adduction strength were measured in 81 players before two consecutive seasons. Thirty-four players were cut, traded, or sent to the minor league before the beginning of the season. Injury and individual exposure data were recorded for the remaining 47 players. Eight players experienced 11 adductor muscle strains, and there were 4 hip flexor strains. Preseason hip adduction strength was 18% lower in the players who subsequently sustained an adductor muscle strain compared with that of uninjured players. Adduction strength was 95% of abduction strength in the uninjured players but only 78% of abduction strength in the injured players. Preseason hip adductor flexibility was not different between players who sustained adductor muscle strains and those who did not. These results indicate that preseason hip strength testing of professional ice hockey players can identify players at risk of developing adductor muscle strains. A player was 17 times more likely to sustain an adductor muscle strain if his adductor strength was less than 80% of his abductor strength.