Increasing mileage safely — forget the 10% rule
One common problem I see with runners is that they increase their mileage too quickly. It’s a problem I see with beginning runners as well as more experienced runners who are coming off an injury or a break in their training. In either case, the risk is the same — if you increase your mileage before your body is ready for it, your chances of getting injured go up dramatically.
So how quickly is too quickly?
The old rule of thumb was to increase your weekly mileage no more than 10% a week. This is a great way to keep from getting injured, but it’s not a particularly effective way to improve your training. Let’s say that you’re a runner who is running a total of 10 miles a week. Next week you can increase to 11 miles. The week after that 12.1. And so on and so forth. In eight weeks you’ll be at 21 miles. That’s a long time for that kind of build-up.
I think the better approach is what Jack Daniels, PhD recommends — increasing your mileage 1 mile per week for each day of the week that you run. Let’s say you were doing 10 miles in four runs. Next week you can run 14 miles. The week after that, 18. And so on.
If that seems too aggressive for you, another tweak that I like is to spend two weeks at each mileage total. So week one is 10 miles. Weeks two and three are 14. Weeks four and five are 18. It’s a little more safe, but still gets you to 22 miles in six weeks instead of the eight weeks it would take if you increased 10% each week.
Obviously each runner is going to be a little bit different, but I’ve found the mile/day approach works very well for runners looking to increase their mileage safely.