Endurance conditioning can help an athlete build and maintain stamina as well as long-term muscle performance for his or her particular sport. It is common in sports that require participants to run or otherwise move for long periods of time, or to maintain positions of strain for long periods of time. Endurance conditioning usually starts with interval training, which means the athlete will participate in short to medium bursts of intense activity with short rests in between. This type of training teaches the muscles, lungs, and heart to be prepared for intense strain without damaging them.
High intensity, short activities coupled with medium to long rests helps develop speed as well as speed endurance. This conditioning is useful for long-distance runners, sprinters, and participants in sports like ice hockey or soccer. Such endurance conditioning results in lower lactic acid build-up, but no real improvement in VO2 max. The longer rest periods allow the muscles to recover appropriately, preserving them for another bout of intense physical activity.
The opposite holds true for aerobic endurance conditioning. Shorter rest periods in between intense physical activity can improve VO2 max, or the maximum amount of oxygen the body can use during intense physical activity. VO2 max is important for sustained physical activities such as long distance running or cycling, and it is important to train the body to take in more oxygen that can reach the muscles to enhance performance.
Programs for endurance conditioning vary from sport to sport, and from one athlete's goals to another's. Athletes participating in sports such as tennis will participate in conditioning that stresses sprinting, lateral quickness, and sustained muscle movements. Such a program may involve sprinting across a gym or tennis court at almost full speed, then jogging lightly for a minute or two before repeating the process. A swimmer may swim two intense, fast laps, then rest and swim slowly for one to two laps to build endurance in the shoulders, arms, back, and legs. Cyclists commonly find a long hill to climb; they will climb at full or near-full speed for several minutes, then rest for a minute, then repeat.
Lactate threshold can also affect endurance, so lactate threshold training is common for endurance conditioning. Lactate threshold is essentially the amount of exercise an athlete can do before lactate levels are too high for muscles to function effectively. Cramps and tightness the day after physical activity are both signs of lactate build-up, and certain exercise routines are designed to increase an athlete's lactate threshold so he or she can continue to use the muscles as long as possible before cramping, stiffness, or tearing occurs.