ABSTRACT
Although considerable documentation of the physiologic effects of ultrasound (US) exists, little information is available concerning direct effects of US on muscle, particularly when the US is applied immediately before muscle performance. The purpose of this study was to determine the effect of continuous US to the anterior tibial muscle compartment on ankle dorsiflexion torque assessed immediately posttreatment, at 30 minutes, and at 60 minutes posttreatment. Seventeen healthy subjects were tested performing isometric contractions at dynamometer velocities of 60 and 180 degrees/sec. Subjects first received either a placebo or a 1.5 W/cm2 15-minute US treatment. One week later, the protocol was repeated with the administration of a second treatment. Analysis of variance showed no significant interactions for time and treatment for any contraction; time, for isometric contraction, was the only significant main effect. Follow-up analyses were all nonsignificant for comparisons of pretreatment to posttreatment and posttreatment to 30- and 60-minute intervals within treatment groups. The study concludes that in spite of known physiologic effects, one treatment of US does not have an immediate or latent effect on peak torque.
