Association of hand grip strength with Ultrasound-derived forearm muscle thickness and echo intensity in young Indian adults

Background: Muscle thickness (MT) quantification, which reflects the muscle function, can be measured using ultrasonography. Echo intensity (EI) quantified from the ultrasonography-derived skeletal muscle images reflects muscle quality. This study aimed to analyze the associations between handgrip strength, ultrasound-measured forearm MT, and EI in healthy young adults. Methods: Sixty healthy volunteers between the ages of 18 and 25 years participated in the study. Brightness mode ultrasonography (USG) was done to measure forearm radial and ulna MT. The EI was measured from an ultrasound image as a mean pixel value using a histogram in Adobe Photoshop. Individuals were tested for forearm handgrip strength using hand dynamometry. Results: Males had higher forearm MT and handgrip strength compared to females. Handgrip strength had a significant positive correlation with forearm radius, ulna MT (r = 0.726, 0.757 and P < 0.01), and forearm circumference (r = 0.529 and P < 0.01) and a negatively correlation with subcutaneous fat thickness (r = -0.496 and P < 0.01) and EI (r = -0.618 and P < 0.01). Linear regression showed a significant correlation between MT, circumference, and EI with handgrip strength (r = 0.825 and P < 0.001). After adjustment for the other two parameters, the forearm MT correlated positively and EI negatively with handgrip strength. Conclusion: USG can be more easily used than other imaging methods in research and clinical setting as it is nonhazardous, less expensive, versatile, and provides results faster. Thus, USG measurements in skeletal muscle are useful for measuring MT and subcutaneous fat thickness. EI measurement can be a convenient and noninvasive method for assessing muscle quality.