You can only make as much progress as you can handle loads in training.FOr instance, if you want to squat 500 pounds as a max you need to be able to train with 70-85% of that, or 350-425 lbs on a regular basis. We can argue as to how often and much much you should train with those loads but the key is being able to work with those weights. If you can do the workouts but they break you down so much you dont get stronger. you get weaker.so recovery is key and is truly the factor limiting how good you will get.
If you want to run a 4 min mile you better be able to do the 20 quarters in 63 seconds that the top milers can do with ease.Not only do those workouts but recover from them stronger than you were going in. Not an easy task and one that requires considerable sacrifice and dedication to accomplish.Building up to those required loads takes many many progressive workouts. And you have to recover from each one. the less the recovery the greater the chance of injury as well.
There are a multiple of facets to increasing recovery not the least of which is anabolics which work well( in the short run) and are easy. Hence their popularity. The least popular are the ones that require thought,work and discipline such as regular massage and body therapy, stretching, active recovery work,nutrition,visualization and not the least of which a very calm, balanced lifestyle and lots of rest as well as sleep.
Olympic and true professional athletes are very lazy when they are not training as they are very jealous of their recovery energy and know the more they waste with superfluous activities the slower their progress will be. It's all a choice of course. Stay out late, have some drinks and party a bit or watch a dvd, doing some mental preparation for the tomorrows workout and get 8 hours of great sleep.It's all about priorities and choices. Every day. Every choice.
Makes a big difference, especially over the long run,positive or negative, which is where all the real progress takes place.If you aren't in it for the long haul you are't in it.
Rest is not the same as sleep and those who never sit down and put their legs up will have very dead legs the next day. This is especially true for endurance athletes,bodybuilders and powerlifters. trying to get to the top of your game requires quite a bit of work and sacrifice, just no way around it.
As I write this though I am struck by how much things have changed for me.Again, this is from the perspective of the specialist athlete whose main purpose was to progress in competition. The concept of the "human animal" who is not training for sepcialzed sport competition but to be "ever ready and fit" to survive is a different way of thinking, and of training for me.
But to progress in your discipline of choice you must be able to do harder and harder workouts. To do that you have to figure out how to recover as fast and completely as possible between sessions.Its all part of the puzzle of experiements and discovery that is training.