Weight training is a type of exercise that uses free weights to build strength. Unlike bodyweight exercises which use your own bodyweight to build muscle, weight training exercises use barbells, dumbbells, kettlebells, or weight machines to increase muscular strength throughout the body. Weightlifting is sometimes incorporated into aerobic exercises to elevate the heart rate for a powerful cardio workout as well. To decrease the risk of injury, beginners should start by lifting lighter weights and gradually work their way up to lifting heavy weights.