If you’ve ever spent an inordinate amount of money after running a race to purchase pictures of yourself taken on the course, you’ve probably noticed shots of yourself landing heel first, ankle slightly flexed as your foot approaches the ground.

That’s, at least, if you’re one of the over 90 percent of all runners (including a significant portion of elite runners!) who heel strike.

As common as it is, heel striking gets a bad rap. Proponents of barefoot running and fans of Christopher McDougall’s Born to Run book and philosophy often argue that landing heel first puts runners at greater risk of injury, and that it’s less efficient. This idea has made its way onto runfluencer social media, where switching from a heel strike to a mid or forefoot strike is sometimes presented as being as simple as just flipping a switch. (Spoiler alert: It’s not.) There are even shoes that claim to promote forefoot striking.

But can something that comes naturally to more than 90 percent of all runners really be that bad?

Why we heel strike

The difference between a heel-striker and a forefoot-striker isn’t just which part of the foot touches the ground first. Where you land on your foot actually determines how you are dissipating ground reaction forces, and what muscle groups you’re using, says Kimberly Melvan, DPT, SCS, CSCS, a physical therapist and running coach. Heel strikers, for example, use more muscles around the knee as well as the tibialis anterior muscle that runs along the shin, whereas forefoot strikers use more muscles in the ankle and the foot.

Usually, how we strike the ground is just a matter of habit, and what feels most natural to us, says Heather Milton, MS, RCEP, CSCS, an exercise physiologist at NYU Langone’s Sports Performance Center. The rise of highly-cushioned running shoes has likely only made heel striking even more common, though, says Dr. Melvan, since all that cushion in the heel makes it easier for that part of the foot to land first since it absorbs the shock.

Is heel striking really so bad?

Forefoot-striking evangelists claim that it is both more efficient and safer than landing on the heel. While experts are divided about whether any one foot strike causes more injuries than another, it is true that landing on the forefoot generally leads to a more powerful stride than landing on the heel.

That’s because heel striking is usually linked to overstriding, or stepping too far out in front of your body. “You have to expend so much energy to then get your body over your center of mass,” says Dr. Melvan. “The vertical loading rates—those up-and-down movements—are also higher when you heel strike, so it’s just not as energy-efficient.” Both heel striking and overstriding usually also come with a lower, less efficient cadence, or turnover.

There are some catches, though. While forefoot striking is more efficient than heel striking, all else being equal, running in a way that doesn’t feel natural to you and that your muscles aren’t accustomed to isn’t going to feel efficient at all—in fact, trying to forefoot strike when you typically heel strike will likely mean your legs will tire much more quickly than usual. Plus, on days when you’re trying to run slow (and yes, you should have these days!), it can be difficult to maintain a forefoot strike while keeping your pace easy.

And none of this means that you can’t run fast while heel striking. Some elite runners heel strike, and even more transition to heel striking at the end of a long race like a marathon. “You can still maintain pretty high paces if you’re a heel striker,” says Milton, “as long as you don’t have high braking forces” (meaning, as long as you’re not overstriding too much).

There are potential injury risks that come with heel striking, especially when runners are also landing with a straight leg. “That doesn’t allow the muscles to absorb the increased force from the heel strike and the overstriding, and that means the joints are absorbing that force,” says Milton. Possible issues include stress fractures, IT band syndrome, anterior knee pain, and shin splints.

But running injuries are almost always multifactorial, says Milton, and even if you could magically change your footstrike overnight, it wouldn’t necessarily mean that nagging pain would just go away. Plus, forefoot striking can come with its own set of injury risks, like Achilles overuse and metatarsalgia.

How to know if your foot strike is a problem

Unless you see a picture of yourself running, you may not even notice whether or not you heel strike. If seeing a running coach or a physical therapist aren’t options, here are a few easy ways to tell on your own: Check out the wear pattern on the bottom of your shoes to see if the heel is more worn down, or have a friend take a video of you running from the side, and watch it back in slow motion. Dr. Melvan recommends the apps Dartfish and Ochy that can help analyze your running form from a video.

While it’s good to be aware of your footstrike, there’s probably no need to try to change it unless it seems to be causing you pain. “It’s that old adage: If it ain’t broke, don’t fix it,” says Dr. Melvan. If you are having pain—especially shin splints or knee issues—it could be related to how you’re landing, and it’s best to seek expert help. But even then, it’s probably not just a matter of learning to land on the front of your foot, says Dr. Melvan, as there could be other issues at play, and trying to change your form prematurely without proper strengthening could lead to even more muscle imbalance and pain. “The overall goal isn’t to fix it, it’s to fix the other things that in combination would lead to more risk for injury,” says Milton.

Having big running goals and a serious commitment to getting faster is another good reason to consider working on making your form more efficient, but again, it’s not just a matter of deciding to forefoot strike. Instead, says Dr. Melvan, a runner would likely work on increasing their cadence, allowing the foot strike to evolve naturally.

“If you want to be faster, maybe it’s something you want to consider,” says Dr. Melvan. “But if you’re someone who just likes to put on your shoes and go out for a run, who cares? If you enjoy it, you’re having fun, you’re not getting hurt, I don’t think it matters what your [foot] strike pattern is.”