The hard days are the stimulus for the improvement but the rest is when the improvement happens.
This is something I often remind the runners I coach, as well as myself.
Why is this important?
Because we need to remember to balance this stress and rest. Too much stress and you’re getting a lot of stimulus but you’re going to break down. Too much rest and you’re going to stagnate, eventually losing fitness. You need to find that sweet spot with just enough stress to stimulate the improvement you’re looking for but enough rest to actually get that improvement.
You also need to remember that hard days need to be adequately hard and easy days adequately easy. A lot of runners do their easy days too hard, often resulting in either breakdown or their hard days not being hard enough. All moderate running neither creates the necessary stress to stimulate improvements nor allows the adequate recovery to get the improvements.
Today’s stress needs to balance tomorrow’s rest because today’s stress is the stimulus for the improvement.
Today’s rest needs to balance tomorrow’s stress because we need to make sure both that we’re getting the most out of our most recent hard training and that we’re adequately prepared for the demands of tomorrow’s training.
It all exists in a balance. Today needs to prepare you for tomorrow and balance out what you did yesterday. It’s all a flowing system and the whole system needs to work together.