In the Introduction to Running Medicine article we discussed the three big factors that relate to running injury risk: structure, mechanics and dosage. This post focuses on dosage. Exercise is medicine, and like a drug, we can prescribe the amount and how often to take it. The three main parts of this dosage are frequency, intensity and time, or F.I.T. for short. Training plans offer a seemingly infinite number of ways to combine these variables. Like with medication, we can also overdose on training, making our graph look like this:

Our mechanics and structure are OK, but our large dosage has put us into the injury range. Not good! While it’s generally agreed that how you train is the biggest factor for both race performance and injury risk, there is a very wide variety of expert opinions and not much research on the best way to go about it. We’ll let the coaches debate the perfect F.I.T. formula and instead I’ll give some general advice on running dosage.

The most important thing is to ease into any changes. We can often link an injury to a recent change in training, such as new shoes, new running group, or adding in speed or hill work. While these changes can be good in the long run, too much too soon can set you back. For example, rather than going all-in with eight 400-meter repeats for your first speed workout, start with just a few easy 400s.

Next week add a few more, the following week pick up the pace a little. Taking several weeks to work something new into your routine will help keep you injury free. It’s helpful to keep in mind all of our bodies’ tissues that need to adapt to training. While cardiac and muscular improvements can start happening in just a few weeks, structures like tendons, ligaments and bones take months to start catching up to higher training loads.

When prepping for a race, follow a training plan. Even if it isn’t a very good one, at least it can be changed and adjusted as needed. If it produces great results, you can follow it again. If you don’t like the results, try a new plan next race. Google can pull up multiple plans for any distance race. Your local running shoe store can often help as well and many offer free group training runs. You can also consider getting a coach for a more personalized approach.

For the beginner, perhaps someone considering doing a 5K for the first time, I’d recommend starting with walking. Once you can walk briskly three times a week for 30 minutes, start adding in some jogging. Break up the 30 minutes into six sets of five minutes. Spend most of the five minutes walking, and a little bit of it jogging. Each week, replace some walking time with more running time. In eight to 10 weeks, you’ll be running 30 minutes straight, which will be close to a 5K for most people.

Beyond this, use the 10% rule to keep building up. Increase your total weekly mileage by no more than about 10%. Consider taking a de-loading week once a month – building mileage for three weeks, then reducing your mileage around 30-40% for a week to let your body rest and recover before resuming building up.

Lastly, here is advice on how to know when to push through discomfort or pull back. These guidelines were developed by my mentor Dr. Bob Wilder:

1.  You can run with mild pain, 1 – 3/10 on the 10-point pain scale, but not moderate or severe, ≥ 4/10.
2.  No running if you are limping or changing your gait to decrease pain.
3.  If the pain decreases as you warm up, it’s generally OK to push through. If it worsens the further you go, you need to back off.
4. Your long run shouldn’t be more than 35% of your total weekly mileage.

I also recommend you consider seeing a doctor if you have pain that is sharp or in a joint, or if the same spot hurts for three runs in a row. It’s best to get diagnosed and treated quickly before it becomes a worse problem.

Thank you for reading and happy running!
Kasey Hill, M.D.