Purpose: This study examined the correlation between the maximum voluntary isometric contraction (MVIC) and the muscle architecture in the extensor carpi radialis longus muscle during MVIC. Methods: The muscle area, volume were measured using a ultrasound imaging system to obtain the muscle architecture during the MVIC. For the mechanical muscle strength measurements, the MVIC was obtained using a dynamometer. Results: There was a significant correlation between the MVIC and the muscle area (r=0.498, p<0.01) and muscle volume (r=0.602, p<0.001). There was a significant correlation between the MVIC and density (r=-0.429, p<0.05). The area showed significant correlations with the muscle volume (r=0.699, p<0.001) and density (r=-0.429, p<0.05). In addition, there was a correlation between the volume and muscle density (r=0.555, p<0.01). Conclusion: There is close relationship between the MVIC and the muscle architecture in the extensor carpi radialis longus muscle during the MVIC.