We all know that the feet are an essential part of running form, down to the range of motion in your ankle to the way your feet hit the ground with every step.
Plenty of runners focus on the importance of foot landing, especially when it comes to footstrike and what part of the foot hits the ground first. However, your method of foot strike isn’t necessarily the most important role the feet have in your biomechanics…
More often, runners face issues based on where their feet land relative to the rest of their body. The most common problem is over-striding, which you’ve likely heard about before, but there’s another issue known as cross-over that also has a major impact on your running efficiency and injury risk.
Let’s review, shall we?
What is Cross-Over Running Gait?
Picture yourself running, and visualize a line that goes straight down the middle of your body — let’s call this vertical line the “center point.”
During stance phase (i.e., when you bear a majority of your bodyweight on one leg), your feet should be landing relatively close to that center point, if not right next to it.
However, your stance foot should not cross that center point while it’s beneath you. Even if just your heel or your big toe is crossing over that line, you run with some degree of cross-over in your gait. Surprisingly, many runners with cross-over run with a majority or the entirety of their foot crossing over that center line.
And here’s the thing: although it sounds like it might be an obvious form error, cross-over isn’t easy to catch with the naked eye. Even if you deliberately try to look for it, it can be hard to truly assess whether or not you cross-over in real-time unless you have data or video evidence to play back. (But more on that later.)
What Causes Cross-Over?
Like other running form errors, cross-over can be caused by a few different culprits — but most often, the problem is correlated with deficiencies in the hip and thigh muscles.
For instance, the infamous problem of running with inactive or weak glutes can contribute to cross-over. As you may know, muscular control in the glutes plays an important role in stabilizing your hips, especially as you bear weight during the stance phase of your gait. Without sufficient gluteal activation or strength, they can’t stabilize the lower extremity, and you’re unable to retain proper leg alignment. When your body tries to compensate for increased stability, it can lead to a combination of lateral trunk lean, pelvic drop, and consequent cross-over.
Many runners will also present overly tight adductors or hamstrings, both of which are responsible for bringing your leg in towards the midline of your body. If either of these muscle groups are too tight, they will naturally drive the leg closer to that center point.
(In some circumstances, an overly tight hip flexor on the opposite side can also pull your stance leg into cross-over. Extremely tight hip flexors can cause some degree of pelvic drop, leading to a chain reaction through the hips and into your stance leg alignment.)
How Does Cross-Over Affect Running?
The problem with cross-over all comes down to the physics of your running.
When your feet land next to that midline of your body, you’re right in the “Goldilocks” zone: it’s the ideal center point that keeps your body balanced through dynamic movement.
But, if your feet land past that line, you cross the ideal point of balance. This is what causes your body to make biomechanical compensations like pelvic drop, trunk lean, or lateral shifts in the upper body.
These may seem like minor changes at first glance, but when you’re running an average of 1,500 steps per mile (multiplied by however many miles you actually run), those slight adjustments will compound quickly and cause overuse symptoms and injuries in specific tissues.
Some of the most common running injuries that are correlated with cross-over include iliotibial band syndrome, shin splints, gluteus medius tendonitis, runner’s knee, and stress injuries in the fifth metatarsal bone (i.e., your pinky toe).
However, it’s important to note: most cases of cross-over occur in combination with other form errors, like the aforementioned compensations. This is because the trunk, core, and hips are deeply interconnected, and they’re all key players in your running. Any muscular deficiencies in these large muscle groups will likely result in other issues that also contribute to running pain and injury.
The largest penalty of running with cross-over is inefficiency. With running, the goal is to channel all forces into forward momentum — but with cross-over, part of that momentum is being spent on sideways movement.
Again, even though this seems to be a minimal problem, the inefficient energy use adds up quickly over the course of a full run. Correcting cross-over can save a lot of energy, allowing you to build your efficiency and performance.
How to Correct Cross-Over in Running
Now that we know the “what’s” and “why’s” of cross-over, we can get to the good stuff: how to correct (or prevent) it from happening.
The first step is to simply be aware of the fact that you’re doing it. Running with cross-over is similar to driving a car that’s out of alignment — you won’t realize that something is off until you get it checked.
This is where real-time running feedback is necessary. It can be as simple as using a mirror or taking a video of your running, or it can be more formal feedback from a proper gait analysis; whatever form it takes, feedback is essential for catching cross-over.
Because once you do catch it, correcting it is relatively simple. With proper muscle length and ample strength and activation in your glutes and core, you can focus on specific drills that help retrain your movement patterns for better foot landing.
One of the most effective drills is as simple as picking a straight line on a track and running over it, ensuring that neither foot hits or crosses over the line. Or, if you train on a treadmill, you can place a piece of tape vertically on the hood of your treadmill. Then, place a mirror in front of the treadmill so you can ensure your feet aren’t crossing over that center point.
To further supplement these gait retraining drills, also be sure to implement habitual workouts to keep your muscles in optimal shape. Focus on stretching your adductors to prevent tightness, strengthening your glutes in running-specific positions, and practicing single-leg shock absorption drills. These don’t have to take up a bulk of your training, but making a regular habit out of them will make the world of a difference in truly preventing cross-over.
(Keep in mind: these training suggestions are specific to correcting cross-over. If you try to fix cross-over without also addressing other possible form errors, like pelvic drop or trunk lean, you’re only shifting the problem. Truly correcting other form errors will require their own targeted training.)
A Fine Line to Walk (…or Run)
Running biomechanics are chock full of complex nuances, and even slight changes can have a crazy amount of impact on your efficiency and injury prevention.
Cross-over is one of the sneakier form errors that runners face, and it could just be the barrier that’s holding you back from your PR. When you learn what it is and how to combat it, you can eliminate the silent killers that are eating into your performance and unlock your training potential.
