Lower Limb Muscles Modeling with Logical Gates for Gait Analysis Instruction

We introduce a novel way to model lower limb muscle sequential activation using logical gates as a real-time system. Each muscle entails contraction onset and relaxation. We analyzed nine muscles involved in gait according to a given contraction and relaxation sequence. Determination of muscle contraction times was taken from previous surface electromyography studies. The circuit developed includes two bits (four states) to describe the contraction level of each muscle, each one controlled by a D flip-flop. The input to the system is the binary representation of one of the seven stages of gait. The output of the system is the contraction states of the nine muscles involved in gait. This circuit is available for instructional devices and demonstration units. As research progresses, relative onset times may be further adjusted after comparing this simulator with surface electromyography.