You may have heard the terms cutback, deload or back-off week spoken by many runners who are training. Essentially you cut back the intensity or mileage every 3-6 weeks during your training, to give your body a chance to recover from all the training stress you've engaged it in. Recovery is the ultimate goal.
“Rested, Refreshed, and Ready to run, the three Rs of peak performance.” ~ Hal Higdon
The body accumulates fatigue during your training and to reap the benefits of your training, proper rest is very necessary. The amount of rest or cutting back that you do will vary based on experience. Generally, for most runners, a reduction of anywhere from 10% - 25% in your mileage during your cutback week will be beneficial. If you are a newer runner, then you can go as much as 50% if needed.
Take for example, someone who runs 40 miles a week, a deload week, based on your experience, could mean running anywhere from 20 (50% reduction) to 32 (10% reduction) miles during your deload week. For your workouts (tempo or intervals), just reduce the # of intervals or the # of tempo miles or reduce the intensity. If you run by duration, scale back the time by the same percentages.
There are no hard or fast formulas for how you should do your deload. In fact, it will vary based on MANY factors. But these general guidelines will help to keep your body fresh and responding to all the training stimuli. And just because it is a deload week, it DOES NOT mean that you should increase your pace on your runs during the week. Remember, it is a decrease in intensity and mileage to give you the MAXIMUM benefit.
The benefits of a cutback or deload week include the following:
Overuse injury prevention
Promote more restful sleep (How to promote a restful nights sleep)
Restore glycogen stores
Prevention of mental and/or physical burnout
The important thing to know is, your training and fitness will NOT suffer because of a deload week. In fact, done properly, the deload will actually boost your strength or fitness.
There are people who sometimes take an entire week off from running to let the body “burn in” the training, so to speak, and their fitness has never been hindered. That first run back after a week off from running might be a tad difficult, and it might seem like you lost fitness, but you will soon see it is short lived.
The main point to understand in all of this is to give your body rest. If you do not, you may find yourself out of running for a while, and all that great training will be like dust in the wind.
The goal of any training for any race should be to arrive at the start line well trained and also well rested.