Pounding the pavement to grow that peach? But, does running actually make your butt bigger?

Running can boost your aerobic endurance as well as power up and tone your glutes — aka your butt muscles. But getting a bigger booty depends on the kind of running you’re doing. Let us explain.

Running can be a great exercise for your butt that builds muscle and burns fat. But building butt muscle by running doesn’t go down like gains in the weight room.

Distance running and sprinting use muscle fibers that affect your backside differently.

Running basically focuses on two muscle fiber types:

  • type I. Slow-twitch fibers (think toned butts used for endurance running like 5Ks and marathons, )
  • type II. Fast-twitch muscle fibers (think muscular butts used for sudden bursts of energy like sprints)
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There’s actually a scientific reason you don’t see elite distance runners with a bedonk: distance runners use type I (aka slow-twitch) muscle fibers.

Type I muscle fibers are smaller and ideal for endurance because they use slow, even energy. When you start running, your body activates these fibers first. They keep you going mile after mile thanks to more blood vessels feeding your muscles oxygen.

This oxygen-fueled system is “aerobic,” which is generally used to describe cardio exercises that help keep your ticker healthy and tone muscles.

So that means you won’t get big ol’ cheek muscles from distance running. But don’t worry, distance running still makes your glutes stronger and more toned.

If you want to make your butt bigger with running, you gotta sprint. Sprinting uses type II (fast-twitch) muscle fibers that use a lot of energy, fast.

Type II fibers are larger and activate during sudden bursts of movement. They have fewer blood vessels because they don’t need oxygen to sustain these short bursts of energy. That makes sprinting an “anaerobic” exercise (no oxygen required) like strength training.

These fibers are also more equipped to grow muscle size, meaning sprinting *can* boost the booty.

When we say running tones your butt muscles, this includes three gluteal muscles:

  • gluteus maximus
  • gluteus medius
  • gluteus minimus

The gluteus maximus is the big kahuna booty muscle, and is actually the strongest, largest muscle on our body! (The more you know 💫.)

Your surrounding leg muscles are also being put to work to propel you forward as you run, resulting in toned:

  • quads
  • hamstrings
  • calf muscles

Running tones up the arms and abs, too. This is because your arms move to help with coordination and balance while you run. Your abs work to keep the core strong and stable.

The energy it takes to run comes from calories via the fat, carbs, and protein you eat. Plus, any fat your body has stored.

According to the National Institutes of Health, you gotta burn about 3,500 calories to lose 1 pound of fat (this takes about a week). But this rate can vary depending on a person’s metabolism. What type of calories are burned can also depend on the type of running.

Running for long distances at lower intensity levels fuels with carbs and fat. After about 30+ minutes of running, your body can start to use stored fat as fuel. To be more science-y, fat is converted from its storage form (triglycerides) to its handy energy source (triphosphate, or ATP) when you run. This is how you “burn fat” by running.

Besides helping fuel your workout, carb intake helps build muscle and create more bulk, including in your glutes. Carbs are actually really important to muscle building because they help muscles recover from exercise and prevent muscle degradation.

When you’re doing high-intensity, shorter-duration exercises like sprints, these rely more on carb calories.

The treadmill vs. outdoor running is a common runner’s quarrel beyond just booty work. In general, it’s likely treadmill running loses when it comes to growing a bigger, stronger butt and wins at getting a smaller butt.

This is because you’re probs not activating your hamstrings or glutes as much on the moving belt. However, a 2020 study found no major differences in the biomechanics of treadmill and outdoor running so that theory is a bit debatable.

But there’s one exception where the treadmill can definitely help grow your butt: the incline feature. Cranking that puppy up can give a nice resistance (like running uphill) and forces you to engage the lower body and core, leading to bigger buns over time.

These moves get that booty poppin’ too, no sprinting required:

P.S. You can add weights, kettlebells, or resistance bands to most butt workouts for more booty-building power.

Sprinting is the key running exercise for bigger buns, hun. It targets type II muscle fibers, which are best for boosting your butt muscles. If you’re looking to tone up and slim down, distance running is your go-to.

Adding in other strength training workouts and even some incline treadmill workouts will also help grow that thang in no time.