In an apparatus for resistance-based muscular force evaluation and training, elasticity at the distal end of a robot arm is made to follow changes caused in the force exerted by the muscles of praxis as a result of changes in angle at the first and second joints. Even when the trainee changes his or her position, he or she may be indicated of and may positively comprehend the direction in which he or she is to exert the force. The robot arm have its distal end secured to the distal end of the link mechanism has elasticity variable with directions. The elasticity is varied to follow changes caused in the force exerted on the distal end of the link mechanism by a set of antagonistic mono-articular muscles and a set of antagonistic bi-articular muscles, as a result of changes in angle at the first and second joints.
