A gym has several options for getting in shape. You can choose between strength training and a variety of aerobics classes. All exercise has benefits, so you may want to combine your workouts. However, you probably want to include strength training even if you're a complete beginner. Here's why. 1. Strength Training Offers Practical Benefits Since you lose muscle mass as you age and get more sedentary, it's good to do strength training on a regular basis at the gym.