Objective: To investigate muscle strength after short term isotonic and isometric exercise. Method: Twenty two healthy men and women were randomly designed isometric and isotonic exercises. Each participant was asked to perform 10 sessions of isometric and isotonic exercises. The assessment measured pre and post 10 sessions exercises by Cybex 340. Result: Isometric exercise significantly increased by $60^{circ}$/sec and isotonic exercise significantly increased by $120^{circ}$/sec, $180^{circ}$/sec. Isometric exercise and isotonic exercise increased by all speeds. Most increased at $120^{circ}$/sec, $180^{circ}$/sec by isometric exercise and $60^{circ}$/see by isotonic exercise but not significantly. Conclusion: Short term isotonic and isometric exercise increase muscle strength. Even if the exercise session is short term, the sessions increase muscle strength.