Encountered this term during physiology lesson today: Detraining
"Detraining refers to the bodily effect experienced when one takes an extended break from regular, vigorous fitness training. Fitness levels and muscle mass can decline during a break that lasts between two and four weeks. While this sort of long-term break may reduce current fitness levels, it may also offer long-term benefits if the person starts retraining, allowing them to achieve higher levels of fitness than before detraining.
If an individual spends several months undergoing extensive, regular training, the body typically adapts and improves in terms of muscle strength and cardiovascular endurance. More than two weeks of abstinence from physical training can often cause a reduction in the peak fitness level. Attempting to retrain after a detraining period may prove to be challenging and frustrating, as the body struggles to reach its past level of fitness.
Detraining may occur due to unforeseen circumstances, such as injury or illness. Physical activity may need to be postponed for several weeks or months, and the affects on the body may be noticed fairly quickly. Resuming training after injury or illness may be difficult at first, but ultimately an extended break may prove to be beneficial.
Many athletes take an extended period of rest to purposefully allow their bodies to detrain. While they may initially lose their current fitness level, the period of rest will allow the muscles time to heal and regenerate. This period of time spent detraining will actually increase the strength of muscle fibers and allow the heart rate to return to normal."
http://www.wisegeek.com/what-is-detraining.htm
Maybe this is why we always say we come back stronger after an injury?
