Since the majority of fitness adaptations occur through recovery, the goal of your training program should be to maximize recovery. In other words, instead of recovering to train, as many runners do, you should train to recover.
The difference is more than semantic. When you recover to train, your focus is entirely on the workouts themselves. Rest is just a necessary evil. You assume that merely completing a workout suffices to deliver benefits -- which isn't true.
When you train to recover, you look at workouts against the backdrop of the recovery opportunities that precede and follow them -- without these, there's no benefit from running. This leads you to adopt better ways of balancing your workouts and rest periods that will allow you to experience greater fitness gains from the same amount of training. Here are six specific ways you can train for recovery:
Create a need for recovery. It's easy to confuse recovery with rest, but rest only results in recovery (and adaptation) if it follows a training stress. A "runner" who rests all day every day has nothing to recover from and is in fact not a runner but a couch potato. The stronger the training stimulus that precedes a period of rest (up to a point), the more pronounced the recovery-adaptation response will be. So the first ingredient of a recovery-based training approach is hard training.
During the build and peak phases of training especially, it's important to do two to four weekly key workouts that leave you thoroughly exhausted. It's also beneficial to overreach during one- to three-week blocks of training within these phases. By training to within inches of the limit of what your body can handle, you create a strong need for recovery that turns into maximum fitness gains between key workouts and during recovery weeks between periods of overreaching.
Space out your key workouts. Because your two to four weekly key workouts are your most challenging workouts, they need to be preceded by adequate recovery so you're ready for them and followed by adequate recovery so you're able to properly absorb them. Your key workouts should therefore be separated from one another as much as possible within the week.
Do recovery workouts. Recovery workouts are relatively short, easy runs that don't challenge your body enough to create a need for additional recovery, so they won't interfere with your recovery from the most recent key workout. But they still carry fitness benefits, because they enhance your running efficiency by forcing your muscles to perform in a pre-fatigued state. Doing recovery runs also allows you to run more frequently than you could if you tried to run hard every time, and by increasing your frequency of training you teach your body to recover more quickly from hard workouts.
Train opportunistically. Opportunistic training is the practice of performing your key workouts when you're actually ready for them, not necessarily when you scheduled them. For example, after warming up for or beginning a key workout, if you decided you didn't feel strong, you'd scrap the workout and instead do a recovery run. Or, if you started a scheduled easy workout and discovered that you felt terrific, you'd complete tomorrow's scheduled key workout today.
When training opportunistically, you let your body take the lead; you don't shackle yourself to a plan. If you plan well you'll be able to perform your key workouts on schedule, but by remaining open to spontaneous adjustments you'll always recover when you need recovery and train hard when you're able to get the most out of it.
On days when you feel neither good nor bad but so-so, it's usually best to go ahead and muscle through the key workout you've planned. As long as your split times aren't far off what they should be, you can trust that the workout is doing you more good than harm.
Monitor your recovery status. Learn to listen to your body and let it tell you when it's not getting adequate recovery, then act accordingly. A sensible way to use running performance to monitor your recovery status is to assign a grade to each workout in your training log: for example, "great," "good," "fair," or "bad." Three consecutive "bad" days indicate that you're in a recovery deficit and should take a day off. A full week without any "good" or "great" workouts indicates the same.
Practice step cycles. Step cycles are recurring patterns of training that last two to four weeks and end with a week of reduced-volume training for recovery. In a two-week step cycle, a week of hard training is followed by a week of lighter training. In a three-week cycle, the first week is relatively hard, the second week slightly harder, and the third week easy. In a four-week cycle, the third week of training is slightly harder than the second.
Planning recovery periods into your training in this way helps ensure that you don't accumulate fatigue during a long training program. It also allows you to train harder during your hard weeks than you'd be able to do if you didn't take planned recovery weeks.
Training for recovery isn't to be confused with training less. By learning to train for recovery, you'll be able to perform at a higher level in the workouts that matter most and get fitter faster.