What Is Strength and Resistance Training? Strength training improves muscular fitness by exercising a specific muscle or muscle group against an external force. It is ideal to lose weight, gain muscle, and/or just to look and feel better. Strength training incorporates the use of light weights, bodyweight exercises and free weights.  It is important that you do not confuse strength training with weightlifting, bodybuilding, or powerlifting. This is a great way to improve