Texture analysis of ultrasound images is a sensitive method to follow-up muscle damage induced by eccentric exercise

The grey level of co-occurrence matrix (GLCM) is a texture analysis approach accounting for spatial distribution of the pixels from an image and can be a promising method for exercise-induced muscle damage (EIMD) studies. We followed up the time changes of two GLCM texture parameters and echo intensity (EI) on ultrasound images after eccentric contractions. Thirteen untrained women performed two sets of ten elbow flexions eccentric contractions. Ultrasound images were acquired at baseline and 24h, 48h, 72h and 96h after exercise. Two GLCM texture parameters were calculated for the brachialis muscle: contrast (CON) and correlation (COR). Peak torque, EI, muscle thickness (MT) and soreness were measured. The peak torque and soreness decreased immediately after the intervention in comparison with all the measures. MT increased immediately after the intervention remaining for 72h (P < 005). Significant increases (P<005) were observed for COR (48, 72 and 96h) and EI only at 72 and 96h. The increasing COR represents high similarity between grey levels, which could be observed on US images after few days on eccentric training for elbow flexors.