My alarm went off at 5.30 a.m. this morning and I had planned to run 10 miles. However as soon as I stood up, I realized my legs had other plans.

I was sore. No doubt from the strength training session and 800-meter repeats I did earlier in the week. I thought I’d feel OK by now, but my hamstrings, quads, and glutes were still achy.

I debated texting my running buddy and canceling our plans. I could just push back my long run until tomorrow, but should I?

Is it OK to run when you’re sore?

Is it OK to run when you’re sore?

The type of soreness I was experiencing is the kind that happens to all athletes after intense exercise or a new type of exercise – delayed onset muscle soreness or DOMS (soreness that starts immediately after exercise is something else). DOMS starts about 24 hours after a workout and can last anywhere from 2 to 4 days. DOMS is caused by small tears in muscle fibers that occur during strenuous activity.

DOMS isn’t too harmful, so you can run through it in most cases. In fact, running with mild soreness can be a good thing. It helps to prepare you both physically and mentally for the pain you’ll experience on race day.

When it’s not OK to run

If you have sharp pain somewhere or one leg, foot, or knee hurts more than the other – don’t run. That type of pain is a sign of an impending injury. If your soreness is accompanied by any cold symptoms or intense fatigue, then don’t run. This could mean you’re coming down with an illness or over-training.  If you’ve had soreness for several days that’s getting worse instead of getting better, then don’t run and see a doctor.

If you have mild soreness and it’s been a while since your last rest day, it’s probably not a good idea to lace up your running shoes (here’s why you need regular rest days). If you have a planned speed session but are dealing with DOMS, it may not be a bad idea to run easy today and make up your speed-work on your planned easy day instead. You may not be able to hit your target paces when sore and it’s not worth the mental anguish.

If you can’t decide if you should run or not, try this test: do one mile at an easy pace and note how you feel. If you feel physically better or the same, keep running. If you feel sorer, stop running. When in doubt, take the extra rest day. Muscles are torn on the run and rebuilt when the body is at rest. Meaning that sometimes an extra day off can be more beneficial in the long run.

I ended up running my scheduled 10-miler this morning. And wouldn’t you know it, after the first mile, I felt great. My legs loosened up, and while I was fatigued by the end, I felt better afterwards than I did before I started. But I’m looking forward to my rest day tomorrow!