BackgroundInstrument-assisted soft tissue mobilization (IASTM) and percussion massagers are myofascial release techniques that have shown acute and residual effects for improving lower extremity ROM. However, no research has compared the effects of percussive massage vs. IASTM on hip PROM. ObjectiveEvaluate the acute and residual effects of these two treatments on passive hip flexion ROM and patient satisfaction.DesignRandomized controlled trial.SettingUniversity laboratory. Participants30M,30F healthy individuals (age=24.52±4.26 yrs,ht=171.20±9.42 cm,wt=78.93±26.28 kg) volunteered to participate but were excluded for any lower extremity injury or surgeries and any contraindications to either modality.InterventionsParticipants were randomly assigned to one of three groups (10M,10F per group): IASTM (using Graston instruments), percussive massager (Theragun Elite), or control group. A researcher blinded to the treatment measured hip flexion PROM with the ankle at 90 degrees before and after treatment on day 1, 3, and 8. Treatments were applied to the dominant posterior low leg and hamstrings for 5 minutes each on days 1 and 3. The control group laid prone for 10 minutes.Main Outcome MeasurementsDependent variables were passive hip flexion ROM and patient satisfaction (0–10 Visual Analog Scale). ResultsThere were no differences between groups over time for hip PROM (F(8,228)=1.96,p=.068,n2=.064,observed power=0.737).. The ANCOVA showed a significant difference in PROM at post-Day 1 treatment between groups (F=(2, 56)=3.771,p=.029,n2=.119,observed power=.665), showing that percussive massager (59.78±9.05°) produced a greater immediate increase in PROM than the control group (56.28±10.87°);(difference=3.38±1.26°; p=.029). Participants were equally satisfied (F(2,76)=0.130,p=.850,n2=.003,observed power=0.068) with the IASTM (9.23±.27) and the percussion massager (9.08±.27).Abstract 417 Figure 1ConclusionsThe percussion massager improved immediate hip flexion PROM more than no treatment, but not more than IASTM. There were no residual effects on hip PROM over time for either treatment.