High-speed running density in collegiate women's lacrosse.

High-speed running density (HSRd) is the ratio of high-speed efforts and distance covered. This study aimed to evaluate differences in HSRd between training, games, and among positions in collegiate women's lacrosse, and correlate HSRd with other training metrics. Data were collected during a collegiate training year (practices n = 162, games n = 14) through players (n = 25) wearing microtechnology. HSRd differed between training sessions and games (p < .001, d = .281) and by position (p < .001, d = .005-.712). Games (14.7 ± 13.8%) had a higher HSRd than training sessions (13.1 ± 13.7%), and goalies had higher HSRd during games than the other positions. HSRd was moderately inversely correlated (p < .001) with max speed (r = -.395-.543) and had low inverse correlations (p < .001) with distance (r = -.134-.225), accelerations (r = -217-.233), and decelerations (r = -.195-.268). Training did not mimic the HSRd of games. Defenders and goalies perform intense reactionary movements to make a defensive play, resulting in higher HSRd.