<b>Comparative Effect of Cross Friction Massage and Vibration Therapy Among Gym Trainees on Delayed Onset Muscle Soreness</b>

Background: Delayed-onset muscle soreness (DOMS) is a common consequence of unaccustomed or intense exercise, particularly eccentric contractions, and is characterized by pain, muscle tenderness, swelling, reduced range of motion, and impaired strength. Although various non-pharmacological interventions are used to manage DOMS, including massage and vibration-based therapies, evidence comparing their relative effectiveness in recreational gym trainees remains limited. Objective: To compare the effects of cross-friction massage and vibration therapy on pain, muscle tenderness, circumference, hip range of motion, and maximal isometric force among gym trainees with delayed-onset muscle soreness. Methods: A randomized clinical trial was conducted among 42 gym trainees aged 20–30 years with DOMS, recruited from two fitness centers in Lahore, Pakistan. Participants were randomly allocated into two equal groups: Group A received cross-friction massage, and Group B received vibration therapy. Both groups underwent six treatment sessions per week for two weeks, along with standardized warm-up and cool-down exercises. Outcomes were assessed at baseline and after two weeks using the Numeric Pain Rating Scale, goniometry for hip flexion and extension, circumference measurement, palpation for muscle tenderness, and repetition maximum testing for functional strength. Data were analyzed using non-parametric statistical tests with a significance level set at p<0.05. Results: Both groups demonstrated statistically significant within-group improvements in pain, muscle tenderness, circumference, hip range of motion, and strength (p<0.001). Between-group comparisons showed that vibration therapy resulted in significantly greater reductions in pain (p=0.001) and muscle circumference (p<0.001), as well as greater improvements in hip flexion (p=0.046) and hip extension range of motion (p=0.008), compared with cross-friction massage. Conclusion: Both cross-friction massage and vibration therapy were effective in managing delayed-onset muscle soreness among gym trainees; however, vibration therapy demonstrated superior short-term effectiveness in reducing pain and swelling and in improving hip range of motion.