Sometimes, problems with your running form are obvious. For example, if after an hour of running your neck and shoulders get increasingly tight, then you have undeniable evidence of something that needs fixing.

Sometimes, though, things aren’t so obvious, either because you don’t notice anything untoward happening while you’re running, or what you do notice doesn’t seem like it matters. Here are four common hidden” quirks that are likely signs of a weakness or imbalance. Fix them, and you’ll run faster and be less susceptible to injury.

QUIRK #1: You notice mud or kick marks on your calves.

Post-run mud smudges on your calves usually mean more than that you’ll be doing a little extra scrubbing in the shower. “Typically, it’s because that person has weak glute muscles, which help stabilise your foot in the stance phase,” says six-time Ironman world champion Dave Scott, who now coaches a wide range of athletes. “The second thing is they have very poor hip extension.”

What this means is when your leg is in the push-off phase, your hips don’t stay square; instead, they twist back a little to allow you to seemingly enhance your push-off. In reality, says Scott, you end up losing power.

RELATED: Build Stronger Lower Legs In 6 Steps

Scott refers to the navel as the runner’s eyeball, and the goal is for it to always look straight ahead. If you’re hitting your other leg, your navel is likely swinging back and forth like a windshield wiper, which causes the hips to open up too much to the side on push-off. When this happens, your foot comes through on the swing phase and hits the side of the opposite leg.

Runners who do this “need to enhance their flexibility in hip extension,” says Scott. “But they really need to strengthen their glutes; that’s a huge, huge problem.”

To help fix this quirk, try the following glute strengthening workout:

QUIRK #2: You notice that the outsole wear on one shoe is significantly greater than on the other.

Excessive outsole wear on one shoe may be caused by a leg length discrepancy, running on an uneven surface, excessive hip rotation, or one leg being more bowed than the other, says Amol Saxena, a podiatrist in the department of sports medicine at the Palo Alto Medical Clinic in California.

If you often run on a uneven surface, try running on a more level surface or occasionally switching sides of the road while running.

“I first ask patients if they run on an uneven road, and if they don’t, then I look at leg discrepancy,” says Saxena. “In my practice, the most common cause is one leg being longer than the other.”

Generally, if one leg is more than 60mm longer than the other, you’ll want a slight lift to correct the difference, says Saxena. On leg differences less than 60mm, physical therapy and strengthening exercises often correct the issue.

Sometimes people don’t have differences in leg length, but their body acts as if they do. This is called “functional short leg,” and back issues could be at the root of this.

“If you have a pinched nerve in your back, you’ll have some weakness in the muscles that the nerves supply, so a leg might flop, drop, slap, or work unevenly,” says Saxena. In this situation, you want to see a back specialist who can address the issue. Physical therapy is often the solution, but occasionally injections are needed.

RELATED: 6 Ways To Come Back Stronger After Injury

Another possible cause of this quirk is lumbopelvic dysfunction, which is a forward/backward or side-to-side rotation in your hip or pelvis. A physical therapist or chiropractor can often show you exercises to rotate your hip or pelvis back into place.

If you notice greater outerwear on one shoe, yet don’t experience apparent problems, you still want to look into what’s causing the difference, says Saxena.

RELATED: 5 Things Your Chiropractor Wishes You Would Stop Doing

“It’s kind of like an uneven car tyre wear. If you’re getting that, it’s probably worth checking.”

QUIRK #3: The callus skin on your feet is asymmetrical or distributed differently on one foot than the other.

In running, we want our body to be symmetrical; we want our left side to match our right. Yet sometimes we have phenomena on one side of the body and not the other, such as a callus on our right big toe but not the other, even though we wear the same footwear on each foot.

“You have to look at different things to figure out the reasoning behind asymmetry,” says distance coach Jeremy Rasmussen. “You can look at calf flexion: Is one more flexible than the other? What’s your great toe extension like on both sides? Most of the time, if you do some physical assessments of these things you’ll find a difference from one side to the other.”

To gauge your calf flexion, stand barefoot with your hips square and the big toe and knee of one leg touching a wall. Then, move back one inch, and while keeping your heel on the ground, lean forward with your knee until it touches the wall. Continue to move back one inch at a time until you can no longer touch the wall with your knee without your heel lifting off the ground. Then do this exercise on the other side. If you achieve the same distance with each side, move on to something else, says Rasmussen. But if you experience a greater distance from the wall on one side than the other, your calf flexion is asymmetric and needs attention.

To measure your great toe extension, put yourself in full calf flexion (toes pointing toward your shin). Have someone pull up on your big toe from side to side. If your two big toes have a different range of motion in this position, you may need to address the difference, says Rasmussen.

For both, it’s simple to work on improvement. “A golf ball-rolling your feet up-or a tennis ball, rolling your calves out,” is the simplest solution, says Rasmussen. “Basically, you are trying to loosen the muscles and tendons.”

QUIRK #4: The horizon appears to bob up and down while you run.

If the horizon appears to be moving up and down while you run, it may be because you overstride and have too much vertical motion. When you take too long of strides, you’re spending more time on the ground than is necessary and increasing your risk for knee and Achilles injuries, says Eugene, Oregon, physical therapist Robert Wayner.

RELATED: A Simple Drill to Correct Overstriding

To help eliminate the moving-horizon sensation, Wayner recommends quickening your cadence to 170-180 steps per minute. Increasing your cadence eliminates overstriding because it makes your foot land underneath you or barely ahead of you instead of way out in front of you. A shorter stride and faster cadence will also decrease the time your feet are on the ground and therefore increase your overall speed. (Try this simple drill to correct overstriding.)
“When [a runner’s] foot makes contact, if he thinks about releasing that foot as quickly as he can, and even saying the words ‘touch, lift, touch, lift,’ that eliminates some of the bobbing,” adds Scott.

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