The 12 3 30 Workout: Tiktok’s Popular Treadmill Routine Explained

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Years ago, the main way that fitness trends took hold was through a slow spread while people observed others doing something intriguing at the gym that they would then replicate.

Then someone else would also see that second person and give it a shot.

Eventually, fitness magazines shared workouts and exercises, and the trends would spread much faster.

Today, we have TikTok.

What was initially a social media platform mostly dominated by videos of people demonstrating their dance moves and trying to one-up one another is now a viable resource chock full of workout ideas and fitness hacks.

Although it’s prudent to be more than a little dubious when taking fitness advice from an amateur video-sharing platform, there can be some pretty cool crowdsourced exercises and workout ideas on TikTok.

If the TikTok algorithm feeds you many fitness videos, there’s a good chance you’ve stumbled upon the 12 3 30 workout or the 12 3 20 workout.

In this article, we will take a look at the 12 3 30 TikTok workout, the 12 3 20 TikTik workout, and whether these TikTok treadmill routines are something you should try.

We will cover: 

  • What Is the TikTok 12 3 30 Workout?
  • What Are the Benefits of the 12 3 30 Workout?
  • Downsides of the 12 3 30 Workout

Let’s jump in!

People on treadmills doing the 12 3 20 workout.

What Is the TikTok 12 3 30 Workout?

Also called the 12/3/30 workout or the 12-3-30 workout, the TikTok 12 3 30 workout is a treadmill workout created by fitness influencer Lauren Giraldo.

On TikTok, #12330 now has over 219 million views, demonstrating the degree to which this treadmill workout has spread like wildfire.

The 12 3 30 treadmill workout is quite simple, though not necessarily easy.

You set the incline of the treadmill to 12%, the speed to 3.0 miles per hour, and then walk for 30 minutes.

Given the walking speed and duration, the 12/3/30 treadmill workout involves walking 1.5 miles.

Although the first few minutes of the workout might not feel too challenging, by the end of the 30 minutes, you’ll likely be breathing hard, feeling it in your legs, and sweating profusely.

Note that beginners might take on the shorter iteration, the 12 3 20 workout.

In the 12 3 20 workout, you still set the incline to a 12% grade and speed to 3.0 miles per hour, but you only walk for 20 minutes instead of 30.

This means that the 12 3 20 workout is a one-mile walk.

People working out on treadmills.

What Are the Benefits of the 12 3 30 Workout?

Unless you’re a fitness fanatic and love exercising just for the sake of exercising, you want your workouts to be as effective and efficient as possible.

With that in mind, does the 12-3-30 treadmill workout work?

The short answer is yes, the 12 3 30 workout can be an effective workout for improving your fitness and health.

Benefits of the 12 3 30 workout include the following:

#1: Building Muscle

Any form of walking activates the muscles in the lower body and core (as long as you’re not holding onto the treadmill handrails).

The 12/3/30 workout involves incline walking up a 12% grade.

This is a steep incline, which significantly increases the muscular demand on the posterior chain muscles (glutes, calves, and hamstrings).

Therefore, any type of incline walking—but especially with a grade as significant as 12%—can strengthen the muscles in your legs.

Posterior chain muscles are often notably weaker and more difficult for people to properly activate and recruit during exercise and activities of daily living.

For example, “dead butt” syndrome is a common phenomenon among runners. It entails an inability to effectively utilize the glutes for powerful leg extension during the running stride.

The glutes should be one of the strongest and most powerful muscles in the entire body and the primary drivers of hip extension (pulling your hip and leg backward) when you walk, run, and jump.

However, many runners and other athletes disproportionately rely on their hamstrings for hip extension.

This is problematic because the hamstrings are relatively weaker than the glutes and have the dual role of extending the hip and flexing the knee.

Therefore, a running stride that is hamstring dominant instead of glute-dominant will not only be less efficient and powerful but can also overly tax the relatively weak hamstrings, increasing the risk of hamstring and low-back injuries.

People working out on treadmills, a close-up of their feet moving quickly.

#2: Increasing Heart Rate

One of the primary benefits of the 12-3-30 workout is that it is a great cardio workout. 

Regular aerobic exercise is important for optimal health and reducing the risk of diseases like hypertension, obesity, heart disease, type 2 diabetes, and certain cancers.

The 12/3/30 workout can absolutely count towards the physical activity guidelines for adults set forth by the Centers of Disease Control and Prevention (CDC) and the UK Government, which are to get 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity exercise per week, is advisable.

Depending on your fitness level, the 12-3-30 treadmill workout will count towards your weekly minutes for either moderate-intensity or vigorous-intensity exercise.

According to the American College of Sports Medicine, the moderate-intensity cardio zone falls between 64-76% of your maximum heart rate, while vigorous cardio would be at an effort level at or above 77% of your maximum heart rate.

Walkers who are more fit will likely have a lower relative exercise heart rate during the 12-3-30 workout, and as you get in better shape, you may transition from being in the “vigorous” exercise heart rate zone to the “moderate-intensity” exercise zone.

If the 12-3-30 workout increases your heart rate into the moderate-intensity physical activity zone, doing the workout five days per week will help you reach the guidelines for physical activity, whereas you will only need to do it three times per week if it’s vigorous activity for you.

People working out on treadmills.

#3: Reducing Impact

One of the best benefits of the 12/3/30 TikTok workout is its low impact while still being relatively high intensity.

Compared to something like running or jumping rope, the 12-3-30 workout is much easier on the joints while still being a fantastic cardio workout.

Incline walking can be a more comfortable and safer form of exercise than running for those with osteoarthritis, joint injuries, and low bone density.

#4: Burning Calories

The metabolic cost of incline walking is significantly higher than walking on level ground, meaning you will burn calories much more efficiently during the 12/3/30 workout.

For example, studies suggest that compared to walking on flat land, walking at a 5% grade increases the energy cost of walking by 17% at a 5% incline, while a 10% incline boosts the caloric expenditure by a whopping 32%.

The more calories you burn during your workout, the easier it becomes to generate the caloric deficit needed to lose weight.

People working out on treadmills.

#5: Posing the Right Level of Challenge

The millions of avid supporters of the TikTok 12 3 30 treadmill workout attest that one of their favorite things about the workout is that it’s challenging but doable.

In other words, it’s enough of a challenge to be motivating and effective but not so hard that it’s totally exhausting and unsustainable as a regular practice.

It’s only 30 minutes, and walking at a speed of 3.0 miles per hour is not as immediately exclusionary as something like running a 6-minute mile or doing 100 burpees.

Sure, the 12% incline adds a lot of intensity, but the reasonable walking speed and duration help make the 12-3-30 treadmill workout quite approachable for many people, even if you’re not in amazing shape.

#6: Easy to Learn and Replicate

As long as you have a treadmill with an automatic incline that can reach a 12% grade, the 12/3/30 workout can be done anywhere at any time.

It takes two seconds to understand the protocol, and then you can replicate it on your own at home or at the gym.

This makes it beginner friendly, great for working out when you’re traveling, and good for people who don’t want to have to make up their own workouts and just want an exercise routine that’s easy to follow.

People working out on treadmills high fiving.

Downsides of the 12 3 30 Workout

It’s easy to sing the praises of the 12/3/30 workout, but there are also downsides.

Depending on your fitness level, it might not be enough of a workout to improve your aerobic capacity.

For example, if you are a runner who consistently trains at a fast pace, this workout might not be vigorous enough to better your current VO2 max, nor will it necessarily help you train for a long-distance race.

Similarly, if you’re used to exercising for longer than 30 minutes at one time, the 12 3 30 workout will not improve your endurance.

The 12-3-30 treadmill workout also might not be practical. 

Not all treadmills go up to a 12% grade, so you may need to modify it based on the capabilities of your treadmill.

A person working out on a treadmill, a close of up their feet.

However, then you’ll be cutting into the intensity of the workout.

Additionally, the severe incline grade can pose a risk of injury to the low back, hamstrings, and calves.

A 12% grade is very demanding on these muscles, so if you jump into doing the 12/3/30 workout without adequate strength in the posterior chain muscles, you can strain the muscles.

You may also aggravate your Achilles’ tendons, feet, and hips.

Finally, if you always do the 12 3 30 treadmill workout at the exclusion of anything else, you’ll create muscle imbalances and reach a fitness plateau—you need variety and gradual progressive overload to develop well-rounded athleticism with continual improvements.

Therefore, while the 12 3 30 workout is a great way to strengthen your legs, torch calories, and get your heart pumping, it’s important to add other types of exercise into your weekly workout routine as well.

What else interests you? Would you like to take up running? If so, join us on a Couch to 5k journey!

A person smiling at the camera, on a treadmill.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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