The Physical Activity Guidelines for Americans recommends adults do two or more days of strength training activities that work all major muscle groups each week. Compound exercises are movements that recruit multiple muscle groups and joints simultaneously for a more efficient, full-body workout. These exercises can be performed using barbell, dumbbells, kettlebells or any other weights. These movements recruit more muscle mass and reduce the time needed to work all your muscles, helping you burn more calories in less time. The goal is to strength train at least two to three days per week, with at least 24–48 hours of rest between. The 5x5 workout involves doing five sets of five repetitions of compound exercises, lifting heavy and increasing the weight over time, then slowly adding 5-10% more weight every two weeks.