Effects of Instrument-Assisted Soft Tissue Mobilization Technique on Iliotibial Band Syndrome in Long Distance Runners. KINESIOLOGY, 2016, 18(3): 43-50. [PURPOSE] To investigate effects of instrument-assisted soft tissue mobilization(IASTM) on flexibility and pain in long distance runners with iliotibial band syndrome (ITBS). [METHODS] Twelve amateur long distance runners with ITBS participated in this study. Jogging with pain test was applied on treadmill with 8km/h speed for 5 minutes. Ober’s test was measured with digital inclinometer. Noble’s compression test and Renne’s test were measured with Numeric Rating Scale (NRS). IASTM was applied for 5 minutes around iliotibial band area, and Ober’s test, Noble’s test, and Renne’s test were measured again immediately after the treatment. This experiment continued for 6 weeks. [RESULTS] Each week of IASTM treatment (pre-post) showed significant change in Ober s test (week 1 p=.01, week 2 p=.02, week 3 p=.03, week 4 p=.001, week 5 p=.001, week 6 p=.004). 6 week Ober s test degree change was not significant(p=.64). 6 week IASTM treatment Noble s compression test change was significant (p=.001). Each week of IASTM treatment (pre-post) was not significant with Noble s compression test (p=.13). 6 week IASTM treatment Renne s test change was significant (p=.001). Each week of IASTM treatment (pre-post) was not significant (p=.22). Jogging pain change in 6 weeks was significant (p=.001). Jogging pain decreased 2.75 to 0 in 6 weeks. [CONCLUSIONS] 6 week IASTM treatment can decrease pain with iliotibial band syndrome in long distance runners.