What Those Smartphone Health Stats Like ‘Walking Asymmetry’ Actually Mean

If you’re ever opened up your iPhone’s Health app out of curiosity to scroll through your stats, you might have come across some startling numbers. A high percentage point on something like “walking asymmetry” in particular might seem… pretty damning. If we can’t even walk symmetrically, what does that say about our health?

Before you race to the physical therapist, it helps to know exactly what this stat can (and can’t) tell you, with a little expert perspective.

Understanding walking asymmetry

The Health app that comes preloaded on your iPhone measures walking asymmetry by looking at “the percent of time that your steps with one foot are faster or slower than the other foot,” according to Apple. Built-in motion sensors automatically record those percentages whenever you stash your phone in a pocket near your waist.

The average walking asymmetry for healthy, younger adults falls between 5 and 15 percent, while older adults are typically closer to 15 to 20 percent, according to a study in the journal¹Medicine & Science in Sports & Exercise.

Those numbers might seem high. But the truth is, humans aren’t symmetrical creatures.

“Our face is not perfectly symmetrical, and our gait is not perfectly symmetrical,” says Hila Glick, BPT, vice president of physical therapy at OneStep, a digital platform that uses the gait analysis on smartphones to gather information about its patients’ overall health. (Heck, even our personal relationships can be asymmetrical.)

“As long as the asymmetry does not bother you—it’s not painful or it’s not visually obvious—then truly, it doesn’t really need to be corrected,” says Anna Di, CES, DC, a certified corrective exercise specialist and chiropractor at Unity Health Wellness in New York City.

And “good” walking asymmetry comes down to how you feel, not what your iPhone’s stats say. “As long as you are able to move your body in a pain-free way without limitations, then numbers on an app really don’t matter,” Di says. “I wouldn’t want anybody to get really over obsessive with forcing themselves to [get] a perfect score.”

DOUBLE SUPPORT TIME

Walking double support time is the phase of your walk when both feet are on the floor. A faster gait will typically lead to a lower number here since you’ll likely have quicker turnover from one foot to the next. The average falls between 20 and 40 percent, according to Apple. “We can learn a lot about a patient who spends too much time on both legs,” Glick says. “This could be a signal that someone might be feeling unstable.” In that case, Glick says, they’d work together on balance exercises and fall prevention.

Causes

Walking asymmetry is a pretty natural phenomenon. “A lot of people have a dominant leg that they always step forward with, or a hip that they always put all their weight on, or some sort of a postural preference as they’re walking,” Di says. Sometimes that’s thanks to a genetic abnormality like having one shorter leg. Or, you might just have built up more strength on a given side over the years. Either way, unless it’s causing unpleasant side effects, your walking asymmetry percentage is not something to stress over.

“If someone is very consistent with asymmetry, we can be calm about it,” Glick says. However, her team stays on the lookout for sudden spikes to see if a patient is suddenly favoring one leg. This could mean that one side has grown weaker than the other, or they’re limping due to pain. (Or, it could simply mean they started carrying a baby on one hip, or regularly walking on an uneven road.)

In rare instances, Di says walking asymmetry can be a sign of a neurological disorder that’s affecting your balance. But it’s far more likely to be caused by something relatively harmless.

If your walking asymmetry is exaggerated enough, it could have ripple effects that might eventually be cause for concern. “Certain joints of the spine or certain muscles might get overused,” Di says. “When that happens, you set yourself up for an earlier onset of degenerative changes to the muscle and the bones.” Before that occurs, however, you’ll feel pain that will alert you that something’s off.

Diagnosis and assessment

To see if your walking asymmetry is more than just a glitch in your iPhone’s sensors, Di recommends giving yourself this health-related fitness test: Use your phone’s camera to record yourself walking or do some strides in front of a mirror that allows you to watch yourself.

“Try to straighten yourself up and then walk a [few] times back and forth (because the first time, people tend to walk perfectly, but then the next couple of times, the weaker side that your body pulls to will start to show through),” she says.

If you find it’s painful to pull yourself upright or don’t have the strength to stay in a centered, balanced position, Di recommends seeing a specialist like a physical therapist, sports orthopedist, or chiropractor who might be able to pinpoint where in your body the imbalance is coming from.

Another easy way to tell if you’re walking in a lopsided way is to check your shoe wear patterns: Both soles should look the same, rather than one getting worn down faster.

Treatment and management

Di asks patients who are struggling with walking asymmetry to do an audit of their lifestyle postures. Maybe they always pick up their kids and put them on the same hip, or maybe they always rest on one elbow at their desk at work. “Purposefully notice when we are leaning our bodies one way versus the other,” she says.

Once you become aware of those habits, you can consciously switch things up. And you’ll also know where you might need to actively stretch and strengthen to even out muscle imbalances.

“If we’re leaning one side, try to make an effort to stretch the opposite way, but strengthen both sides,” Di says. For instance, if you’ve got uneven strength in your legs and glutes, exercises like lunge variations can be beneficial. Or, if you think something’s going on further up the chain, check out your mobility with moves like the Apley Scratch Test.

More than anything, keep walking! Research² suggests you can get major health benefits from walking 7,500 steps a day, which translates to about three to four miles, depending on your stride length. Glick points out that, in general, for those of us who can walk, doing it more often and being aware of the quality of our walking is one of the best things we can do for our health.

“This is how we move around—not with squats, and not with swimming,” she says. “We walk our way around the world, so we want to make sure this basic skill is being done with the best quality possible.”