OBJECTIVES/SPECIFIC AIMS: Compare the short- and long-term effects of 2 treatments, MST and SF, on limitations in function, pain, and movement characteristics. The movement characteristics included the amount of early excursion (1st half of decent) of the knee, hip, and lumbar spine during a functional activity test of picking up an object. METHODS/STUDY POPULATION: 154 participants were randomized to 6, 1-hour treatment sessions (once/week for 6 weeks) of MST or SF. The MST group received individualized training to modify pain-provoking altered movement patterns during functional activities. The SF group received exercises for trunk strength and trunk and limb flexibility. At baseline, post-treatment and 6-month follow-up participants completed the modified Oswestry Disability Questionnaire (MODQ, a functional limitation measure; 0-100%), the Numeric Pain Rating Scale (NRS, average pain prior 7 days; 0-10) and a standardized pick up an object test, where sagittal plane knee, hip and lumbar spine excursion were calculated using 3D motion capture. A mixed model repeated measures ANOVA was used to examine the following effects: Treatment group (Tx), Time and Tx X Time for each self-report and movement variable. When the ANOVA was significant (p < 0.05), a priori planned contrasts were examined. RESULTS/ANTICIPATED RESULTS: There was a significant Tx X Time interaction (p < 0.01) for each outcome. Baseline: MST and SF were similar in MODQ scores [Δ 0.4% (−3.4 − 2.9)], NRS [Δ 0.0 (−0.6 − 0.6)], knee [Δ 2.2° (−6.7 − 2.5)], hip [Δ 0.4° (−2.9 − 2.5)], and lumbar spine [Δ 0.1° (−1.4 − 1.2)] early excursion. Post-Treatment: Both group’s MODQ and NRS scores decreased (p < 0.01), but MST had a greater reduction in MODQ scores [Δ −7.6% (−3.9 − −11.0)] and lower average NRS scores [Δ −0.8 (−0.1 − −1.4)] compared to SF. MST changed knee [Δ +18.6° (14.6 − 22.1)], hip [Δ +10.8° (8.5 − 13.1)], and lumbar spine [Δ −2.0° (−3.0 − −1.0)] early excursion, while SF did not change early joint excursion (all p > 0.72). 6-Month Follow-up: The differences between MST and SF were maintained for all outcomes (p > 0.26). DISCUSSION/SIGNIFICANCE OF IMPACT: MST was more effective at reducing functional limitations and pain and improving movement patterns during a functional activity compared to SF. For all variables, the differences identified during treatment between MST and SF were maintained at 6-month follow-up. Therefore compared to SF, MST that targets performance of altered movement patterns during functional activities appears to be superior for attaining and maintaining changes in functional limitations, pain, and movement characteristics in people with CLBP.