If you’re a sprinter and you take a handful of weeks off, you’ll likely experience less of a performance hit than a distance runner. This is because your speed and strength will stick around longer than your muscle endurance when you take a long break from training. Why is that? Well, muscle endurance has everything to do with having a lasting energy source, and the energy generators in the cells, mitochondria, can decline in number quickly with inactivity.
Here’s a little more background and some useful tips for distance runners to keep their endurance up if and when they need to take some time away.
Two Weeks Too Many
If you just take off a few extra days from your training, you’re probably fine. Of course, “fine” is a relative term – you might be a mini basketcase or a bit of a grump, but the break shouldn’t have any noticeable physiological effects at least.
Performance typically starts to take a hit after about 7-10 days of inactivity. By the time you hit a two-week hiatus, you’ll almost certainly start to feel the effects of detraining on your endurance. Your mitochondrial density (more on this in a sec) will decrease and enzyme activity in your mitochondria will slow down, causing your endurance to plummet. You’ll probably also start to see an increase in body fat, especially if you’re eating the same way you were when your training was in full tilt.
Mitochondria: The Little Engines That Can
Stretch your memory all the way back to freshman year bio. You might vaguely recall your teacher saying something about the mitochondria being the “powerhouse” of a cell. How do these little blobs in your cells work their magic? With the help of oxygen, they break down carbs, fat and protein to release the energy stored inside.
The trick here is that your body can actually increase the number of mitochondria in each cell. And that’s just what it’ll do in response to increased energy needs. Increased mitochondrial density in your muscles helps to improve endurance by giving your muscles an adequate source of energy when running at a faster pace. But just as your body can increase mitochondrial density, in a classic case of ‘use it or lose it,’ the body will also decrease that density quickly in response to inactivity.
If you’re unable to train the way you normally do because of an injury, illness, or hectic schedule, try to create a modified training plan. The focus of this plan is simply to maintain the benefits of your prior training during your hiatus. Clear your training modifications with your physician before you try them, to make sure you won’t be prolonging or aggravating your injury with activity.
Whenever possible, reduce how much you train, rather than just burying your running shoes in the closet. This could mean cutting mileage, or stepping down from six workouts per week to three or four. If you have a joint injury, try working out on an elliptical to eliminate impact. For something like a stress fracture you might try cross-training in the pool. Engaging in an endurance activity other than running (like swimming) will keep your mitochondria density up, and can help you maintain your endurance when you’re ready to lace up again.