A muscle activity output system includes: a muscle activity database configured to hold movable part attitude information and muscle activity information in such a manner that the movable part attitude information and the muscle activity information are linked to each other; and a processor. The movable part attitude information indicates an attitude of a movable part of training equipment. The muscle activity information indicates a muscle activity of each of muscle sites of the exerciser. The processor is configured to acquire the movable part attitude information while the exerciser is moving the body along the trajectory, acquire current muscle activity information for each of the muscle sites based on current movable part attitude information of the training equipment and the muscle activity database, and output the current muscle activity information for each of the muscle sites.

A left leg unit includes a vertical piece; a horizontal piece; a vertical guide groove; a horizontal guide groove; an outer coupling bar to which the vertical piece and the horizontal piece are rotatably coupled, thereby coupling the vertical piece and the horizontal piece to each other; and a pedal that is rotatably coupled to the outer coupling bar. The vertical guide groove and the horizontal guide groove are extended in such a way that they intersect with each other. A rotation axis of the pedal is disposed away from a rotation axis of the vertical piece and a rotation axis of the horizontal piece and is disposed away from a midpoint of a line that connects the rotation axis of the vertical piece and the rotation axis of the horizontal piece, whereby the rotation axis of the pedal moves along an elliptical trajectory.