Abstract: BACKGROUND: Instrument-assisted soft tissue mobilization is often used as a noninvasive treatment for soft tissue (skeletal muscle, ligament, and fascia) injuries and postoperative recovery to improve pain and enhance strength in the range of joint motion.
OBJECTIVE: To compare the clinical efficacy of instrument-assisted soft tissue mobilization and massage therapy in patients with lateral epicondylitis of the humerus.
METHODS: A total of 25 athletes with lateral epicondylitis of the humerus were enrolled in this study and randomized into two groups: 13 subjects receiving instrument-assisted soft tissue mobilization as the experimental group and 12 subjects receiving massage therapy as the control group. The treatment period was 4 weeks, with two sessions per week. Elbow joint visual analog scale, Mayo elbow performance index, elbow range of motion measurement, and forearm strength were measured and recorded in both groups before and after treatment. 
RESULTS AND CONCLUSION: Both treatments significantly reduced visual analog scale score of the elbow joint after the first and last treatments (P < 0.05), but the visual analog scale score showed no significant difference between the two groups (P > 0.05). The Mayo elbow performance index showed a significant increase in both groups after the first and last treatments (P < 0.05), but there was no significant difference between the two groups (P > 0.05). In the maximum grip strength test, the maximum grip strength of the experimental group in the vertical direction and during internal and external rotations after treatment was better than that before treatment (P < 0.05), while the control group only showed improved maximum grip strength during internal rotation (P < 0.05), with no significant improvement in maximum grip strength in other states. There was also no significant difference in the maximum grip strength in all the three states between the two groups (P > 0.05). After the last treatment, the range of motion of the elbow joint and the angle of forearm pronation and supination were significantly improved in both intervention groups (P < 0.05). The maximum angle of the elbow joint for flexion was smaller than that before treatment (P < 0.05), and there was no significant difference in each angle of motion between the two groups (P > 0.05). The range of motion of the forearm and elbow joint in both groups were significant improved after the first and last treatment (P < 0.05) and there was no significant difference in difference in the range of motion of the forearm and elbow joint between the two groups (P > 0.05). To conclude, both instrument-assisted soft tissue mobilization and massage therapy significantly reduce pain, improve elbow flexibility and increase joint range of motion in patients with lateral epicondylitis of the humerus. However, instrument-assisted soft tissue mobilization is better than massage therapy to improve the maximum grip strength.

Key words: lateral epicondylitis of the humerus, instrument-assisted soft tissue mobilization, massage, myofascial, fascia densification, physical therapy