When it comes to strength training, you need to work in the sweet spot in terms of the number sets you do. Fear not, that sweet spot has been found, and you probably won't be surprised to learn you should do two to three sets of each exercise. According to a review of studies published in the Journal of Strength and Conditioning Research, doing two or three sets will make you 46 percent stronger than just doing one. Talk about motivation. However, there were no strength benefits found in performing more than three sets of an exercise. Muscles just max out and can only respond to so much stimulus, so no need to sweat about adding in that fourth set of jumping lunges or leg presses.