The goal of training basically comes down to improving our fitness so that our zone of "ease and familiarity" gets faster and further. Thank you to the beauty of the way our bodies are created, if we stretch ourselves outside our comfort zones then adaptations occur that enable us to go further and faster next time before reaching the edge.
On the other hand, if we never venture into that unfamiliar, uneasy space outside of our comfort zone, then there is no reason for our bodies to adapt. Thus the well known saying "no pain, no gain".
All pain, no gain. No rest, no gain.
What we need to realize is that after a hard workout, our bodies are much like a ship that has been rammed onto the rocks and if we don't take time out for repair, the ship she will sink.
Often when people talk about top athletes, the conversation is centered around what workouts they do and how many miles they log a week. What is actually key though with these high level athletes, is the amount of detail that goes into the recovery and repair process plus, how much of those 100 mile weeks is actually really easy running. As much as twice a day training and voluminous track workouts are all in a days work, so are afternoon naps and massages.
Secondly, these athletes have been stretching their comfort zones bit by bit consistently over many years. With the result that they have very big, very fast comfort zones. What sounds like a near impossible workout to the average club runner, is most likely just outside their comfort zone.
I find the process much akin to stretching a blob of plasticine. If i just pull it fast, it breaks in two. But if I gradually stretch, press, rub the cracks, stretch, press, roll repeat then I can form the shape I want. Slowly. With time.
It all comes down to stimulus and response. You need the right kind of challenging stimulus. And you need to allow time for a response. And then repeat. And repeat. And repeat.
The Law of Comfort Zones can be thus be summarized as:
The right amount and right kind of pain at the right time followed by the right amount of recovery, repeated consistently = Gain.
Onwards and upwards!