Resistance training increases muscle strength by making your muscles work against a weight or force. Different forms of resistance training include using free weights, weight machines, resistance bands and your own body weight. A beginner needs to train two or three times per week to gain the maximum benefit. As laid out in the "U.S. Army Fitness Training Handbook," these seven principles also are known as PROVRBS, an acronym for progression, regularity, overload, variety, recovery, balance and specificity.