How do your muscles work when you perform simple motions (such as sitting in a chair) or when you lift weights? How does strength training increase your bone density and lower your risk of osteoporosis? What factors determine how much strength you generate from a specific muscle movement? What are the specific guidelines for beginning and advanced strength trainers? What role should strength training play in flexibility and children’s fitness? Get scientifically backed answers to these and other questions on strength training and your body.