Strength training is a popular term for exercises that build muscle by harnessing resistance against an opposing force. The resistance can come from your body, or from free weights, elasticized bands, or specialized machines. It makes muscles stronger. Another type of training, known as power training, is proving to be just as important as strength training in maintaining or restoring function. As the name suggests, power training is aimed at increasing power, which is the product of both strength and speed. Optimal power reflects how quickly you can exert force to produce the desired movement. Here’s an example: Faced with a four-lane intersection, you may have enough strength to walk across the street. But it’s power, not just strength, that can get you across all four lanes of traffic before the light changes. Likewise, power can prevent falls by helping you react swiftly if you start to trip or lose your balance. Some power moves are strength training exercises done at a faster speed. Others rely on the use of a weighted vest, which is worn while performing certain exercises that are typically aimed at improving functions such as bending, reaching, lifting, and rising from a seated position.