An exercise monitoring apparatus, system, and method are disclosed herein to reliably monitor an exercise using an inertial sensor and a electromyographic sensor. The sensed information may be used to determine a muscle fatigue associated with the exercised muscle and may reduce health risk factors associated with immoderate exercise. The exercise monitoring apparatus as embodied and broadly disclosed herein may include a communication unit adapted to receive muscle movement and electromyographic information from a physical information measuring apparatus. The exercise monitoring apparatus may further include a controller configured to acquire identification information related to the muscle, determine a type of exercise based upon the acquired identification information and the muscle movement related signal, and measure muscle fatigue based upon the type of exercise, the muscle movement related signal, and the electromyographic signal.