The present invention discloses a modular brace, mountable on a joint, configured for exercising at least one muscle connected to, or otherwise affecting the function of, the joint, the brace comprising: lateral and medial rigid articulated cages, lateral and medial replaceable elastic members, and at least one joint-covering, replaceable elastic member. The lateral, medial, and at least one joint-covering, replaceable elastic members are configured to produce predetermined resistance force against muscles connected to the joint. The lateral and medial cages are configured for restriction of the joint's motion to the normal articulation of the joint. At least one joint-covering elastic member is adapted to simultaneously protect the joint from external insult while preventing pressure on the same.
