Today on the Doc On The Run Podcast, we’re talking about how ankle stiffness can lead to another stress fracture in a recovering runner.
Let’s say you’re out on a run and you start feeling some aching pain in your foot, and then the next day you wake up, it really hurts when you step out of bed. So, you go see a doctor and you’re told you have a stress fracture. Being told you have a stress fracture is a real bummer because in most cases, the doctor will tell you that it’ll take about six weeks to heal and that you need to wear a fracture walking boot for about four to six weeks, and of course, you can’t run during that time. So let’s say that you go with that plan, you stick around in the boot, you don’t do anything, you don’t take it off, you don’t run, you don’t exercise, and then you get clearance to run.
Then when you first go for your run, after you’ve been cleared to run, everything feels super stiff. Your running form’s terrible, you feel really slow, but you really notice more than anything else that it’s super stiff around your ankle. Why is that? Well, it’s really simple. There’s a lot of research that’s been published on this that actually shows that if you’re immobilized in a cast or a fracture walking boot for about two weeks, you kind of get a free pass. There isn’t that much trouble. You get a little trouble, but it’s not the end of the world and it’s really easy to work past it. However, if you go six weeks, a couple of things happen around the ankle joint that cause problems. Anytime you hold a structure completely still like your ankle or your elbow or your knee, you start getting indiscriminate collagen forming in all areas that actually stick tissue planes together where things are supposed to glide past each other and it starts to lock up the joint and make it stiffer.
How stiff is really simple. Research has showed that can this actually cause five times the amount of torque to get your foot to the end range of dorsiflexion where you’re pulling your foot up away from the ground. That’s dorsiflexion. So when your knee is moving forward over your foot, that’s dorsiflexion. When you’re on the ground standing there on your heel and you pull your foot upward away from the ground, that’s dorsiflexion. But it takes five times the amount of force to get to the end range of motion in your ankle joint after you’ve been immobilized in a cast or a fracture walking boot for about six weeks. Now, in addition, you have a 70% decrease in dorsiflexion, so it comes up nowhere near as far, and it takes a whole lot more force to get it there.
The reason that’s a real problem is that when you start running, if you think about it in terms of how your foot really works, well, it’s a lever on the end of your leg, and if it takes five times the amount of force to push up on your foot when you’re running, that increases the force going through the structures in your foot like the metatarsal bones, the tendons, and ligaments, everything. So you actually become more at risk of getting an over-training injury that’s related to excess stress like a stress fracture. And I will tell you that when somebody gets a stress fracture and they sit around in a boot and they start running, this seems to happen at the worst possible time, you finally feel like you’re moving again, you finally feel like you’re running again, and then you get injured again with a different injury. That’s really, really demoralizing.
I’ll tell you, I had a patient one time who had a really bad sesamoid stress fracture, and in her case, she was wearing the boot, she wasn’t able to use crutches because of her job, and it took almost 12 weeks for the thing to actually heal. So that’s great, it was healed. I had custom orthotics made for her to actually support her foot and take stress off of that bone that had the stress fracture so that I knew she was best protected when she moved out of the boot. Well, the next day, after she got out of the boot, she called me and she was literally in tears crying and I said, “What happened?” She said, “Well, I know you told me I had to kind of break in the orthotics and I should take a while before I started running again, but it was a beautiful day and I’d spent so long in the boot. I just thought I’d go for a really short run down by the Marina Green and ran three miles, and I woke up this morning, my foot’s black and blue.”
She had completely fractured a completely different bone with that one run, even in custom orthotics. That is because of the weakness and stiffness that you get as a consequence of being immobilized for a long period of time. So there are some things you can do to mitigate it. You can do things like the static gastroc stretch or the eccentric stretches, but it depends on the injury you’ve had because some injuries will be made worse if you do the eccentric stretches and some injuries will be made worse if you do the static gastroc stretches. So you got to make sure you’re doing the right stretches given your particular circumstances.
If you found this episode helpful, please like it, please share it, and I’ll see you in the next episode.
The effect of nontraumatic immobilization on ankle dorsiflexion stiffness in rats. Reynolds CA1, Cummings GS, Andrew PD, Tillman LJ.J Orthop Sports Phys Ther. 1996 Jan;23(1):27-33.
