Immediate and residual changes in dorsiflexion range of motion using an ultrasound heat and stretch routine.

OBJECTIVE: With respect to increasing ankle dorsiflexion range of motion, our objective was to examine the influence, if any, of preheating the triceps surae with ultrasound before stretching. DESIGN AND SETTING: Subjects were assigned to either group A (ultrasound and stretch) or group B (stretch alone). Group A received 3-MHz ultrasound (1.5 W/cm(2), 4 times effective radiating area) for 7 minutes to the musculotendinous junction of the triceps surae before stretching. Group B rested for 7 minutes before stretching. Both groups then performed identical calf stretches for 4 minutes. Treatment for both groups was conducted at the Brigham Young University Sports Injury Research Laboratory twice daily for 5 days with at least 3 hours between procedures. We analyzed the data with a 2 x 3 x 10 factorial analysis of variance with repeated measures. A Tukey post hoc test was used to identify significant differences in range of motion. SUBJECTS: Forty college students (male = 18, female = 22, age = 20.4 +/- 2.5 years) volunteered for the study. MEASUREMENTS: Maximal ankle dorsiflexion range of motion was measured using an inclinometer before and after each treatment. RESULTS: Immediate effects were that ultrasound and stretch increased mean dorsiflexion range of motion in all sessions significantly more than stretch alone in three treatment sessions. Residual effects were that dorsiflexion range of motion increased 3 degrees in both groups after nine treatment sessions; however, neither group significantly outperformed the other. CONCLUSION: As studied, an ultrasound and stretch routine may increase immediate range of motion more than stretch alone, possibly enhancing performance in practice and competition. This increased range of motion, however, is not maintained over the long term and is not more than the range of motion gained from stretching alone. A similar study using subjects with decreased range of motion after immobilization or injury should be conducted to see if the ultrasound and stretch regimen would produce lasting range-of-motion increases.