Purpose/Hypothesis: Evidence suggests physical activity benefits brain health and cognition.2,3,4 Aerobic exercise improves academic and cognitive performance, specifically executive brain function.7,13,14 Past studies show improved cognitive measures following low intentensity resistance training (RT).2,3,4,6,7 There is a lack of research on the effects of heavy RT, 85%-95% 1 repetition max (RM), on cognition in physically inactive persons or females. Executive function is a set of processes required for cognitive control of behavior; problem solving, memory, inhibition, and attention.7 The Stroop assesses an individual's ability to inhibit cognitive interference.5 Multiple studies explored the effect of aerobic exercise on Stroop performance.8,9 No studies explored the effect between RT on Stroop performance.The purpose of study was to analyze the effect of heavy RT on cognition in college female students. We hypothesized heavy RT would improve Stroop test performance in untrained female college students. Number of Subjects: Twenty-eight healthy untrained college females randomly assigned to a strengthening group (n=14) or stretching group (n=14). Materials and Methods: Participants in the strength group attended 4 RT sessions over 2-3 weeks at 50% effort and a 5th session to determine 1 RM. Two to three days following the 5th session, subjects completed a heavy RT session. The heavy RT session consisted of 3 sets and 6-8 reps 85-95% of 1 RM. Stroop tests were administered prior to the first training session and immediately before and after the final RT session. Results: Participants in the strength group attended 4 RT sessions over 2-3 weeks at 50% effort anda 5thsession to determine 1 RM. Two to three days following the 5th session, subjects completed a heavy RT session. The heavy RT session consisted of 3 sets and 6-8 reps 85-95% of 1 RM. Stroop tests were administered prior to the first training session and immediately before and after the final RT session.Mann-Whitney U tests demonstrated no significant (P>.05) difference in age or BMI between groups. Test-retest reliability was moderate for the Stroop congruent (ICC2,3=0.79) and Stroop incongruent (ICC2,3). 2x2 mixed ANOVA with post-hoc tests demonstrated significant (P=.00) improvement in Stroop congruent and Stroop incongruent scores for the strength group and no significant (P>.05) difference in the flexibility group between sessions 1-2 and 2-3. There was significant difference in Stroop congruent scores (P=.036) and no significant difference between Stroop incongruent scores (P=.069) at session 2 prior to the heavy RT session. After a single heavy RT session there was a significant difference in Stroop congruent (P=.001) and Stroop incongruent (P =.016) scores, with the strength group out-performing the flexibility group. Conclusions:The Stroop test is a reliable measurement of reaction time and executive function. Four weeks of RT at 50% intensity improves reaction time but not executive function. One heavy RT session significantly improves reaction time and executive function, whereas stretching does not improve these cognitive functions. Heavy RT leads to increases in executive function similar to aerobic exercise. Clinical Relevance: Heavy RT can be used to improve executive function, which is required for problem solving, memory and attention, and may improve academic performance in female college students.