The 3-Day Rule This Elite Runner and Coach Swears By to Ward Off Injury

I showed up at the physical therapist’s office, certain I’d broken something. It was April of 2017, a high point in my professional running career. The year prior, I’d come in ninth overall and first American in the Boston Marathon, then finished eighth in the New York City Marathon. Instead of another spring marathon, I was competing in a series of shorter road races, including the Carlsbad 5000 and several U.S. Championships. I did long runs on Sundays. On Mondays, I would run on the AlterG anti-gravity treadmill to increase my volume while putting less strain on my body. Still, I developed pain on the outside of my right ankle. When I told the physical therapist—Bob Cranny, who also happens to be pro runner Elise Cranny’s dad—he introduced me to the three-day rule. With an acute issue like this one, he told me, it usually takes about 72 hours for the body’s inflammatory response to calm down. That might be all I needed. If it was still flared up after that, I could consider getting an MRI or an X-ray. I listened, and it worked. After three days on the bike instead of running, the pain decreased. I did a few more days on the AlterG, then got back to my regular training. At the end of that month, I ran 1:10:54 to place second in the U.S. Half Marathon Championships in Columbus, Ohio. I’ve used this rule many times over the years and have largely avoided serious injuries. And I also recommend it to the athletes I work with through my Get Running Coaching platform. This rule doesn’t work for chronic problems—if it’s something you’ve struggled with for a long time, three days probably won’t fix it. It’s also not applicable to traumatic or serious injuries. If you feel something pop in your foot, if you fall and bang your knee and you can’t walk, or if your pain is severe or you can’t bear weight, you should get medical attention. You’ll probably need more time to heal. But if you have something new pop up on a run or afterward—a muscle or joint that’s sore or inflamed, especially if it’s just on one side of your body—it’s a good guideline, if you commit to it. This rule of thumb takes the stress of making decisions away initially and prevents you from making a bad call—like whether or not to back out of a goal race. Choosing to limp your way through a training run is how you wind up being out for three weeks or three months instead of three days. You can take the three days off completely; it won’t hurt your fitness. Some of my athletes are happy to catch up on other life stuff or focus on getting more sleep. If that’s you, awesome—do that. Other people say being out of their routine is stressful. In those cases, we swap in something that’s low-impact. Depending on what you’re dealing with, you might be able to cross-train to get an aerobic stimulus while still offloading the area so the acute response subsides. If you have a hip or knee issue, the bike might irritate it, but you can try an elliptical, a rower, or the pool. Yoga or something similar can be good, too. I tell my athletes to do what’s accessible to them and what feels right. Always talk with your healthcare team about medications. With their approval, you can try anti-inflammatories during this time—I tend to use naproxen (Aleve) and curcumin (a natural remedy). You can also channel your energy into other techniques to support healing. I’ve responded well to dry needling, Icy Hot, KT tape, and massage. Sometimes I go back and forth between the hot tub and the swimming pool, as a type of contrast bath, doing some stretching in the warm water to get the blood flowing. After the three days, if your discomfort has decreased, try a short, easy run and see how you feel. I’ll often do a short loop—two miles or so. That way, I’m never far from home if I need to stop and walk or call it early. Another good option is to run on the treadmill. It’s a more controlled environment, and you can hit the stop button or hop off whenever you need to. If things improve in the first 10 minutes of your run, that’s a good thing. However, if it takes longer than 10 minutes to loosen up, then you’re probably not ready to get back into running. Or if you can run fine, but pain increases afterward or that night, that’s considered a step back and would show that you need more time or, potentially, medical treatment. Sometimes, you don’t even need a test run to determine that. When I was training for the Berlin Marathon in 2024, I developed pain in the same spot on the outside of my ankle, in the peroneal tendon. I took my three days off, and nothing changed. So I went to see my healthcare team—physical therapist, chiropractor, and massage therapist. They recommended a couple of weeks off from running and provided treatment, including dry needling and strengthening exercises. All that was effective, and I’m confident it allowed me to return to training sooner than if I’d pushed through the injury. I eased back into running using the Lever system, a portable device that turns any treadmill into an anti-gravity one. I ran 2:36:54 in Berlin, achieving my goal of sub-2:40. Right now, I’m around a year postpartum with my third child, Oslo. I’m back to running—including many stroller miles—and will probably target another marathon, in hopes of qualifying for my fifth Olympic Marathon Trials. Eventually, I’d also like to run all the World Marathon Majors in under 2:40, something only a handful of women have done. I’ll continue using this rule to stay healthy as I do. And for the more than 1,000 runners I’ve coached over the last 12-plus years, it’s been helpful to have this guideline to support them. The three-day rule makes things simpler initially, when you could potentially make an emotionally charged decision. And, it keeps you healthier in the long run. Cindy is a freelance health and fitness writer, author, and podcaster who’s contributed regularly to Runner’s World since 2013. She’s the coauthor of both Breakthrough Women’s Running: Dream Big and Train Smart and Rebound: Train Your Mind to Bounce Back Stronger from Sports Injuries, a book about the psychology of sports injury from Bloomsbury Sport. Cindy specializes in covering injury prevention and recovery, everyday athletes accomplishing extraordinary things, and the active community in her beloved Chicago, where winter forges deep bonds between those brave enough to train through it.