Since insufficient muscle forces mean that people cannot perform some activities well related to roles of the muscle, muscle force have been considered as an important parameter in clinic. Therefore many methods have been introduced to estimate muscle force indirectly. One of the methods is muscle tissue dynamics and it is widely used in commercial software including musculoskeletal model. They, however, need motion data captured from 3-dimensional motion analysis system. In this study, we developed a system for estimating muscle force in real-time by using joint angles. The heel-rise movements were performed for a normal with 3-dimensional motion analysis system, EMG measurement system, and goniometer. Joint angles obtained from goniometers and EMG signals were used to estimate muscle forces. Simulation was performed to find muscle forces using motion data which was imported into musculoskeletal software. As the results, muscle lengths and forces from developed system were similar to those of commercial software in pattern. Results of this study would be helpful to understand and to analyze motion in clinic area on real-time.