Strength and conditioning refers to the process of enhancing an athlete's physical abilities, like strength, power, speed, and agility, to improve performance and reduce injury risk. It involves using a variety of exercises and techniques to build strength, endurance, and overall athleticism. Strength training can increase muscle, tendon, and ligament strength as well as bone density, metabolism, and the lactate threshold; improve joint and cardiac function; and reduce the risk of injury in athletes and the elderly. For many sports and physical activities, strength training is central or is used as part of their training regimen. This article will cover many topics including principles and training methods, comparisons of different exercises, nutrition, history, and safety concerns.