Just as it's important to challenge and confuse your muscles by using different weight-lifting equipment, you can increase the benefits of weight training even more by varying the tempo, or speed, of your reps.
While very slow repetitions challenge the endurance strength of the muscle, it's important to incorporate a variety of tempos into your workout, including medium and faster-paced speeds. Change up your speed by doing three sets: one slow, one medium, and one quick. Or vary your speeds on different days. You can also change the speed within each rep. Lift slowly and lower quickly for a set and then do the opposite. Using these varying tempos challenges the muscles with different rates of tension, increasing the benefits of strength training and making you stronger. Tempo variations work well with exercises that use dumbbells, resistance bands, medicine balls, machines, or no equipment at all.