What Muscles Does The Treadmill Work?

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Treadmills are one of the most popular pieces of cardio equipment for home gyms or even for use at commercial gyms. But, have you ever wondered, what muscles does the treadmill work?

How can you alter the muscles worked by treadmill workouts by adjusting the settings on the treadmill?

In other words, do the muscles worked with incline treadmill running and walking differ from flat treadmill running and walking?

In this guide, we will discuss the benefits of using a treadmill to strengthen your muscles, including tips on how to vary your treadmill runs and walks to strengthen different muscles ultimately answering your question, what muscles does the treadmill work?

We will cover: 

  • Is the Treadmill a Good Workout? 
  • What Muscles Does The Treadmill Work?
  • What Muscles Are Worked By Incline Treadmill Running and Walking?
  • What Muscles Are Worked By Treadmill Running and Walking On a Decline?

Let’s jump in!

People running on a treadmill.

Is the Treadmill a Good Workout?

One of the main benefits of the treadmill as a piece of home cardio equipment is that a treadmill, by nature, is quite functional.

You can use a treadmill for walking or running, and both walking and running translate to improvements in functional fitness—walking faster or longer for fitness or health or running faster or longer for performance or fitness.

This is in contrast to something like an elliptical machine that, while it can provide a great form of low-impact cardio exercise, doesn’t necessarily translate directly to improved performance for running or functional fitness for everyday life activities.

To that end, because you can do treadmill walking workouts or treadmill running workouts, the singular piece of cardio equipment can be versatile in the intensity of your workouts and the type of exercise that you do.

Along the same lines, as we look at the muscles worked by treadmill running and walking, we will see that treadmills that offer adjustable inclines allow you to target different muscle groups. 

People running on treadmills.

This further increases the versatility of treadmill exercise and will allow you to have some control over the “treadmill muscles worked” based on the settings you use on the treadmill.

Most of the best home treadmills and commercial gym treadmills have automatic adjustable incline capabilities. This means that you can do incline walking or incline running on a treadmill with the push of a button.

The entire running deck of the treadmill will then start to lift up using a motor to the incline that you select.

Some home treadmills can support a 10% incline or potentially even up to a 15% incline.

The incline on a treadmill represents the gradient or percent grade. This is a measure of the vertical gain in feet for every 100 feet of horizontal distance traveled.

For example, if you are doing an incline walking workout on a treadmill at 12% grade, for every 100 feet that you walk, you ascend 12 vertical feet as well.

There are numerous benefits of doing incline running and walking workouts on a treadmill.

For one, incline running on a treadmill can replicate hills for running hill workouts.

A person running on a treadmill.

If you are training for an outdoor race or trail race where you will encounter real hills, using the incline on a treadmill can help you replicate the muscular and cardiovascular demands of running uphill on the road or trail.

Secondly, incline walking or running workouts on a treadmill burn more calories and increase your heart rate, so using the incline is a great way to boost the intensity of a treadmill workout without increasing the joint impact stress.

Most importantly, at least in terms of our present discussion on the muscles worked by treadmills, doing an incline treadmill walking workout or incline treadmill running workout will help target different muscles worked on the treadmill.

What Muscles Does The Treadmill Work?

The treadmill muscles worked will depend on the speed and grade of your treadmill workouts.

In other words, the muscles used on the treadmill for flat, incline, or decline walking and running workouts will be slightly different.

To this end, the muscles worked walking versus running on the treadmill are similar, but the workload will be more demanding when you are doing running treadmill workouts vs walking treadmill workouts.

Overall, the primary muscles worked on the treadmill include the hamstrings, quads, glutes, hip flexors, and calves in the lower body.

You can also work your core muscles and upper-body muscles with treadmill workouts if you use a vigorous arm swing and do not hold onto the handrails on the treadmill.

A person on an incline treadmill.

What Muscles Are Worked By Incline Treadmill Running and Walking?

Compared to walking or running on the treadmill at 0% grade, putting the treadmill up at an incline to walk or run provides a more intense cardiovascular workout.

Incline walking or running on a treadmill is more demanding on the heart and muscles of your legs because your body has to work against the added resistance of gravity as you ascend an incline.

As a result, the muscles need additional oxygen and nutrients to fuel your workout.

Consequently, your brain (via the autonomic nervous system) signals your lungs to breathe faster and deeper, increasing your respiration rate and tidal volume (the amount of air you inhale per breath).

This helps take in more oxygen to meet the higher demand for oxygen by the heart and muscles.

The autonomic nervous system also causes the heart to beat faster and harder, increasing cardiac output by increasing both your heart rate and stroke volume (the amount of blood pumped out of the heart every time it beats).

People running on treadmills.

Studies show that even when you don’t increase the speed, increasing the grade with incline walking or running increases your heart rate during exercise.

This means that the heart muscle has to work harder during incline treadmill workouts—at a higher percentage of your maximum heart rate, which is the highest number of beats per minute your heart can contract—relative to walking or running at the same speed on a flat belt.

The steeper the incline, the greater the muscular demand on the muscles of the posterior chain (glutes, calves, and hamstrings).

Therefore, any type of incline walking—but especially at higher incline levels—can strengthen the muscles in your legs.

It’s particularly beneficial for people to strengthen the glutes, which is one primary muscle groups targeted by treadmill running or walking up an incline.

People running on treadmills.

What Muscles Are Worked By Treadmill Running and Walking On a Decline?

Whether your goal is to maximize muscles worked by treadmill workouts or you simply want to use a treadmill for training as a runner to enhance performance, I highly recommend spending a little more money when you buy a home treadmill so that you get one that also has a decline feature.

Some of the best home treadmills now have automatic decline as well as adjustable incline so that you can simulate downhill running.

For example, I absolutely love the BowFlex Treadmill 22.

You get all of the premium features you would expect from the best home treadmills like a 22-inch immersive HD touchscreen for streaming guided workouts on the JRNY app (you get a free year!), a roomy  22 x 60-inch running belt to accommodate taller runners with a longer stride, and the ability to run up to 12 miles an hour (5 min/mile).

More importantly, this powerful home treadmill allows you to automatically adjust the incline and decline from -5% decline to 20% incline!

People running on treadmills.

This maximizes the muscles worked by the treadmill and the versatility in the types of running and walking workouts you can do.

Ultimately, the treadmill decline feature is super helpful for training for any race that has significant downhill mileage (think Boston Marathon training or training for any trail ultramarathon!).

The muscular load for downhill running is different from running on flat land or incline/uphill training. Therefore, actually having the ability to adjust the treadmill to a decline will help you strengthen the muscles worked running downhill.

This is also helpful for hikers who will be doing a lot of elevation changes with long thru-hiking or ascending and descending mountains.

The muscles worked by treadmill decline workouts are primarily the quads.

You will still work the other muscles used for running or walking on a treadmill such as the hamstrings, glutes, calves, core muscles, and even the muscles in your upper body, but the decline increases the workload on the quads, which have to help prevent excessive knee flexion.

If you are keen on using the treadmill to strengthen your muscles and improve your cardio fitness, check out our guide to training for a marathon on a treadmill here.

A person running 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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