Sometimes when you run outside, your body feels incredible. And other times when you run, you feel like your body is a bag of bones that just got slapped and pounded against the pavement for 30 minutes straight. Your legs might feel like jello, or they might feel sore and tight, particularly the backs of your legs down by your ankles.
This tenderness you're feeling in the back of your heel could be your Achilles tendon, which is the band of connective tissue that's responsible for transferring load (aka force or weight) from your calf muscle to the bony heel of your foot, says Ryan Balmes, PT, DPT, a board-certified sports and orthopaedic clinical specialist in Chamblee, GA.
Most of the time, Achilles tendon pain can be attributed to overuse and overload, which can happen acutely or chronically, Dr. Balmes says. For example, if you're a novice runner who usually doesn't run during the week, then decides to run three times a week without easing into it, your Achilles might feel a little off, he says. "It's really intense, and if your body didn't have the foundational strength through your calf and the Achilles tendon, then those symptoms will arise," he says. "The body is smart and it lets you know, Whoa, that was a little much. Can you please watch it next time we do something like that?"
Or, if you are an experienced runner and you're already running several miles a week, then Achilles pain could be a sign that your rest period or recovery strategies aren't ample enough for your Achilles, Dr. Balmes says. Over time, you'll just keep chronically pounding away on your Achilles tendon without giving yourself time to rest and stretch, and the overload of forces can cause tightness and soreness, he says.
Then there are the other factors besides duration and intensity that could be impacting how your Achilles feels, like incline and surface, Dr. Balmes says. If you usually run on a treadmill and transition to running outdoors, that could be a lot for your Achilles, he says. Or if you start running on a steep incline, that could change how your Achilles responds to force.
Most of the time, Achilles pain is a sign that you need a break, at least for a bit. But if you're getting this type of nagging pain each time you exercise, then it's important to strategize your overall training plan to prevent it, Dr. Balmes says. That means, structure your training plan or workouts so that they progress slowly toward your goal and allow for recovery. (Or if you're following a running training plan that includes rest days, actually take them!) Before each workout, you should try dynamic stretches and exercises that get the ankle moving and prepare your body for the bouncing you'll be doing through the calf, he says.
Hopefully, this can help reduce the pain, but you should see a physical therapist or healthcare provider if it gets worse or turns into a sharp pain, Dr. Balmes says. "Physical therapists provide a hands-on approach that's very customized to what your goals are," he says. "And we get really nitty gritty into details that may be leading up to the pain." They can also suggest stretches or exercises to help strengthen the calf muscle so that the Achilles takes less load.
In general, it's also a good idea to get enough sleep, hydrate well, eat a good diet, and manage your stress levels to prevent all types of injuries, Dr. Balmes says. Also, switch up your running shoes every six months or 200-300 miles to make sure your feet are properly supported, he says. So, while taking a break from your usual running routine to rest your Achilles might be a bummer, consider it an excuse to buy a new pair of running shoes.