When working with runners, I often see people coming in with knee pain, front of the shin pain, shin splints, and those types of things. Gait modification – watching them run – is something that’s really common for people to be looking for, and is something that we do with all of our runners. If someone is coming in for running, we want to watch them run to see if there is anything from a form standpoint that we can modify, and progress to be able to change where the forces are. A lot of times, form changes and gait modifications are tough to get lasting long term, but in the short term, we can modify forces to keep you running while we work on some of the other limitations – whether it’s strength or mobility limitations or some kind of training error. If we can modify your gait mechanics and modifying training, then we can get you back into running the way that you typically will.
The way we do this is typically through your cadence, through step frequency. A lot of people have heard this, a lot of PT’s and folks that have gone through sources like Runner’s World, or another PT, have heard about that 180 frequency, which is what people are most trying to strive for. A lot of times, what I’m doing is showing them this equation [Speed = stride force (f) x stride length (l)], and modifying their frequency based off where they’re at now. We know that speed is your strike frequency times your stride length. It’s just a simple equation: how fast you’re going to run is based off the frequency of steps you’re taking and the length of those strides. What we’re doing when we’re watching you run is we’re counting your steps, taking that number and, based off the research, if your shin is in front of the knee area, we can increase that step number by 5 to 10%. A lot of times, especially with knee, if we can decrease the force with a 5% increase in step frequency, we can decrease the force by 20%, which is huge. If we modify that force, then we’ve given you the capacity to go run. You can do your typical training, while we work on and address that limitation you have at your knee from a force standpoint. From a capacity standpoint, we’re working on strength and mobility to keep you running, and then flip the script and let you go into your typical running style.
The way this works is that speed is held constant. When we watch somebody run, we watch them at a certain speed, we count the steps they’re taking, and we look to see what their stride length is. We view their stride length basically from an eyeball test. If we’re watching somebody here (foot is in front), that’s going to apply braking force and is going to increase force and pressure through the shin. We want that knee to have a little bit of a bend in it, we want that shin to be up and down, and we want that foot/ankle to be closer to the ground. Ideally, there’s a little bit of bend, shin angle is upright and when their foot is flat it’s closer to being under their hips/center of mass. If someone’s foot is too far out front, that foot angle is increased and that shin angle looks more like this (\), where they’re kind of reaching that foot in front of them, we’re going to want to use this equation to modify. What we do, is we hold Speed constant. We change frequency and then look for length to change. If we keep Speed constant, we want to increase frequency by five to 10%, which means that length is going to go down based off a simple math equation.
The mistake that a lot of people make is that they try to change the frequency to match whatever number they’ve heard is best, and when they increase frequency, length stays the same, and Speed increases, or maybe length increases a little bit, but the noticeable difference is that their Speed increases. We need your speed to be held constant so that we can increase the frequency number and decrease the length number. The most common mistake I see is that people don’t hold Speed constant. That’s where a treadmill is nice, because the treadmill is that speed at a certain place, so you can keep it constant, or you have got to have feedback within your watch to know that your speed is not fluctuating too much. I am not just running faster because I’m taking more steps, I’m actually maintaining speed and taking more steps, which is shortening the length of my stride.
This is the biggest concept that we can go through, and a lot of times a visual is helpful because most people have said they know that they need to increase their stride frequency, they’ll do that, they’ll increase their speed as well, and then they don’t see any change. They use the same mechanics that had before; that shin has been driving forward, that foot is off the ground and they’re braking and applying force to their shin and their knee with every single step. We can just hold Speed to be constant and increase your frequency, a lot of times only about five to 10%, we can decrease the force on your knee by upwards of 20% by shortening up that stride length and by getting more underneath your body.
Here at Peak Endurance Performance & Physical Therapy we help active adults in the Madison Area get back to the activities they love without pain or limitations. We see people of all ages, ability levels, and individuals trying to get back to a multitude of movements including: getting back into running, women postpartum, CrossFit athletes, climbers, gymnasts, wrestlers, overhead athletes, and your recreational weekend warrior. If you’re looking to get back to the activities that give you meaning, relieve stress, and make you feel like you again, feel free to reach out below and we’ll see if we’re the right fit for you.
