Effects of low-intensity pulsed ultrasound on muscle thickness and echo intensity of the elbow flexors following exercise-induced muscle damage

摘要

Purpose The aim of this study was to analyze the effects of pulsed ultrasound on muscle thickness (MT) and echo intensity (EI) after strenuous exercise. Methods Forty healthy untrained male were randomized in either experimental group (n = 20) or placebo group (n = 20). Muscle thickness and EI of the dominant elbow flexors were collected at baseline (PRE), immediately post (0 h), 24, 48, 72, and 96 h after the protocol of damage induction. The protocol of damage induction was performed on an isokinetic dynamometer and consisted of four sets of ten repetitions of maximal eccentric and concentric contractions. The experimental group was treated with pulsed ultrasound (1:4, 1 MHz, 0.8 W/cm2, 23 min) at 0, 24, 48, and 72 h following the protocol of damage induction. The placebo group received the same time of application, but the equipment was kept turned off. Results The results demonstrated that MT and EI significantly increased at all time points after the exercise (p < 0.05). However, neither MT nor EI showed any significant difference between groups at any moment (p < 0.05). Conclusion Pulsed ultrasound is ineffective in enhancing recovery from exercise-induced muscle damage.