What training principle states that you must continue to exercise to maintain fitness?
balance
overload
progression
reversibility

The training principle states that you must continue to exercise to maintain fitness is reversibility. This principle states that if the mobility training is ceased, the ranges of movement will decline over time or if you stop working out, you will lose the effects of training. Regular use of mobility exercises is crucial for improvement.

no, because those are both different running competitions. while distance runners train their legs and their lungs to run long amounts of time, the sprinters are training their legs and their lungs to give all they have in the little amount of area they need to cover. the brain also plays a huge part in all of this.

the brain is the only thing in your body that sends messages to your body telling you to run. if you are a long distance runner and you have the mind set of a sprinter, you will not get anywhere. if you have a long distance mind set and you have to run 200m in 20 seconds then you will not make it in time.