The purpose of this work was to develop a robust EMG-driven elbow model to estimate muscle forces and joint torques of different people performing different time-varying loads at the elbow. The model consisted of an anatomical model, an EMG-to-activation model, a Hill-type muscle model, and a nonlinear optimizer. All of the major muscles about the elbow were taken into account. The parameters used by the muscle model were optimal fiber length, maximum contraction velocity, pennation angle, tendon slack length, and maximum muscle force. EMG and joint angle were input variables. Moment arm and muscle length varied as a function of joint angle, as defined in the anatomical model. The model was used to examine the importance of accounting for muscle velocity during rapid loads applied at fixed joint angles.