10:13 AM

12 + 3 + 30 = trouble?

stock photo of a person doing an incline walking workout

The latest workout to captivate social media requires you to dust off your math skills: three miles per hour on a treadmill at an incline of 12% for 30 minutes. That’s 12 – 3 – 30, for short.

Give it a try, and you’ll feel the burn quickly in your rear end and the back of your thighs. But for the workout to be sustainable, there are a few things to keep in mind.

Matt Janus, a well-being coordinator at OSF HealthCare, says incline walking is great for people who have maxed out their speed but want a more intense workout. Your heart and muscles have to work harder.

For the 12 – 3 – 30 plan, though, Janus recommends starting slow.

“Make sure you’re able to walk at three miles per hour without an incline. Then slowly make the incline higher until you can do that 12% consistently,” Janus says.

“If you go into a workout full force without much preparation, it increases your chance for injury and burnout,” he adds.

When someone is starting a new workout program, Janus recommends three sessions a week. If you don’t feel overworked, you can slowly increase to four or five workouts per week.

“With incline walking, something people experience a lot is shin splints. We’re not used to that flection of our foot and those shin muscles working so much,” Janus says. “So just make sure you listen to your body. If you have a lot of soreness, feel really tired or don’t feel like you can complete the workout, don’t feel like you have to push through and overtrain. You need recovery just as much as you need that workout.”

That may mean taking a day or two off from exercise. If symptoms persist, see your health care provider.

Other tips to conquer 12 – 3 – 30:

  • A walking workout feels more natural, Janus says, when you let your arms sway by your side. But since walking at a steep incline can cause balance difficulties, there’s nothing wrong with holding onto the treadmill rail. As you get more comfortable, try letting go.
  • Don’t feel like you have to do the 12 – 3 – 30 plan exclusively.

 “Variability of your workout routine is really important,” Janus says. “Our body is really good at adapting to the stressors and stimuli we put onto it. Over time, if we’re doing the same thing in the same conditions every day, it will get easier. And eventually, you’ll need to change up the intensity or the whole workout to really progress.”

 Try walking outside instead of on a treadmill. Alternate between incline walking and flat surface walking. Mix in some weight training.

  • Any workout should begin and end with a good stretch and include hydration.

Learn more

Learn more about orthopedic care on the OSF HealthCare website.

Interview clips


View Matt Janus 12 3 30 B-roll
Matt Janus 12 3 30 B-roll
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General 12 3 30 B-roll