Principles of Training (2)
The next two general principles of training are specificity and reversibility. Specificity is really talking about the idea that fitness gains are specific to the type of activity performed. So if you want improvements in running, you need to run. If you want improvements in muscular strength, you have to perform specific types of resistance training that build that muscular strength. And if you want to get even more detailed, you can think about this as particular activities. So if you're doing bicep curls, you're going to strengthen the muscles of your bicep; it's not going to have any fitness effects on the lower half of your body, for example the quadriceps in your legs. So when you think about developing physical fitness, the activities that you choose must be specific to the type of fitness that you want to develop. Fourth is the principle of reversibility. Here we just mean "Use it or lose it." It's a pretty common phrase that you hear pretty often, and it's the idea that these fitness gains are not permanent, so you must continue to be active to maintain the adaptations that you have made from being physically active and exercising. That doesn't mean that rest is not important; rest is an important part of an effective training plan, but here we're talking about periods of rest that are a week or longer where you might see declines in the adaptations that were made from previous physical activity.