Over-reaching is required to stimulate your body to adapt. Full recovery is required to allow that adaptation to take place. Partial or no recovery leads to partial adaptation, lack of performance gains and eventually, over-training.
The quicker and more complete your recovery from a workout, the faster you can move on to your next quality training session. The more total sessions you have the energy for, the faster you will ultimately be.
Top Secret Ergogenic = Full Recovery
No matter what you do, when you extend yourself, your body requires a specific amount of time to refuel and repair. Full recovery takes time.
USA Triathlon Level II coach Steve Seide says: "Quality training time is extremely valuable. By quality, I mean when you are fully recovered and able to put in complete effort and focus. These sessions should be spent wisely."
Plan adequate rest into your weekly routine and schedule a rest week every third or fourth week. Manipulate volume and intensity during rest weeks to unload accumulated fatigue, maintain fitness and sharpen performance.
Recently, I did a big volume, three-day block of training. As an athlete, it was thrilling to put down some huge training. As a coach, I know it should take a week to recover and produce benefits from this type of training.