Weight training for Fitness & Endurance
Weight training causes micro tears to the muscles being trained; this is generally known as microtrauma. These micro-tears in the muscle contribute to the soreness felt after exercise, called delayed onset muscle soreness (DOMS). It is the repair to these micro-trauma that result in muscle growth. Normally, this soreness becomes most apparent a day or two after a workout. However, as muscles become adapted to the exercises, soreness tends to decrease.
Weight training aims to build muscle by prompting two different types of hypertrophy: sarcoplasmic and myofibrillar. Sarcoplasmic hypertrophy leads to larger muscles and so is favoured by bodybuilders more than myofibrillar hypertrophy, which builds athletic strength. Sarcoplasmic hypertrophy is triggered by increasing repetitions, whereas myofibrillar hypertrophy is triggered by lifting heavier weight. In either case, there is an increase in size and strength of the muscles (compared to if that same individual does not lift weights at all). However, the emphasis is different.
Many trainees like to cycle between the two methods in order to prevent the body from adapting (maintaining a progressive overload), possibly emphasizing whichever method more suits their goals. i.e. a bodybuilder will use sarcoplasmic hypertrophy most of the time, but may change to myofibrillar hypertrophy temporarily in order to move past a plateau.
Endurance in sports
Endurance training is essential for a variety of endurance sports. A notable example is distance running events (800 meters upwards to marathon and ultra-marathon) with the required degree of endurance training increasing with race distance. Two other popular examples are cycling (particularly road cycling) and competitive swimming. These three endurance sports are combined in triathlon. Other sports for which extensive amounts of endurance training are required include rowing and cross country skiing. Athletes can also undergo endurance training when their sport may not necessarily be an endurance sport in the whole sense but may still demand some endurance. For instance aerobic endurance is necessary (to varying extents) in racket sports, football, rugby, martial arts, basketball and cricket. Endurance exercise tends to be popular with non-athletes for the purpose of increasing general fitness or burning more calories to increase weight loss potential.