There are many positive things running does for your body: It strengthens your heart and lungs, it helps tone your legs and sculpt your calves, and it can tighten and tone your core. But what does running do to your butt?
Although it can be a funny question to look up online, many people want to know how running affects the butt. Does running make your butt bigger?
Running can strengthen and tone the glute muscles, potentially enhancing the buttock’s appearance, i.e., making it bigger. However, its effect on size depends on individual factors such as genetics, training intensity, and diet.
Beyond the realm of aesthetics, the implications extend to functional strength and performance enhancement.
What Does Running Do To Your Butt?
So, what does running do to your butt? The short answer is: it depends. Running has the potential to make your butt bigger, and it has the potential to flatten your butt or make your butt smaller.
In either case, when we are talking about what running does to your butt, we are essentially referring to two aspects of the butt: the butt muscles known as the glutes (gluteus maximus, gluteus medius, and gluteus minimus) and body fat.
Running can affect the size of your glutes, the amount of subcutaneous body fat stored in your butt1Frojo, G., Halani, S. H., Pessa, J. E., Pazmiño, P., Wall, S., Kenkel, J. M., & Del Vecchio, D. A. (2022). Deep Subcutaneous Gluteal Fat Compartments: Anatomy and Clinical Implications. Aesthetic Surgery Journal, 43(1), 76–83. https://doi.org/10.1093/asj/sjac230, and the relative ratio of muscle mass to fat in your butt, all of which together can affect the size, shape, and firmness of your butt.2Konopka, A. R., & Harber, M. P. (2014). Skeletal Muscle Hypertrophy After Aerobic Exercise Training. Exercise and Sport Sciences Reviews, 42(2), 53–61. https://doi.org/10.1249/jes.0000000000000007
Does Running Make Your Butt Bigger, Or Does Running Make Your Butt Smaller?
Whether running makes your butt bigger or smaller primarily depends on two things: the type of training or running you’re doing and your overall diet.
Let’s cover the diet first since it’s a little easier to understand.
Gaining weight, whether building muscle mass or gaining body fat, is a matter of a caloric imbalance between how many calories or how much energy you are eating and how much energy or how many calories you are expending.
When you are consuming more calories than you are expending, you will gain weight. The converse is also true: when you are burning more calories than you are consuming, you will experience weight loss.
With that basic principle in mind, running, which factors into the energy expenditure side of the equation, has the potential to build muscle and increase the size of your glutes and thus make your butt bigger.
This is possible when specific training is done in the context of adequate protein intake and a small caloric surplus, enabling muscle growth.
Similarly, when combined with a healthy diet or balanced diet that provides a moderate, sustained caloric deficit, running will help you lose body fat.
So, does running shrink your bum?
If your body shape has a fair amount of stored fat in the hips and butt, running can make your butt smaller.
You have to create a caloric deficit of about 3,500 calories to lose one pound of stored body fat.
For this reason, the more you run, or the higher your overall training volume, the more calories you will burn. And, if you don’t make compensatory adjustments in your diet by increasing your food intake, the more calories you burn, the more weight you will lose.
In these cases, running more will gradually decrease the size of your butt as you lose body fat.
How The Type of Running You Do Affects Your Butt
Now let’s get into the nitty-gritty of the way in which the type of running you do factors into whether running makes your butt bigger or smaller.
Running utilizes most of the major muscles in your body, particularly those in the lower body, like your glutes, hamstrings, quadriceps, and calves. Thus, consistent training can increase the strength of your glutes.
However, not all runs are created equal when it comes to building the size and strength of your glutes.
Our skeletal muscles are composed of a couple of different types of muscle fibers.
Characterized by differences in properties such as muscle fiber size, mitochondrial density, the primary way in which the muscle fiber uses energy, and the type of contraction the fiber is capable of.
Although this is somewhat of an overt simplification, there are two primary types of muscle fibers that runners should be familiar with3Wilson, J. M., Loenneke, J. P., Jo, E., Wilson, G. J., Zourdos, M. C., & Kim, J.-S. (2012). The effects of endurance, strength, and power training on muscle fiber type shifting. Journal of Strength and Conditioning Research, 26(6), 1724–1729. https://doi.org/10.1519/JSC.0b013e318234eb6f:
Type I Muscle Fibers
These can be thought of as endurance muscle fibers. They are smaller, contain many mitochondria, and generate energy aerobically (in the presence of oxygen).
Type I muscle fibers are relatively fatigue resistant, so they can contract and power long distance running, though their peak force output and the speed in which they can contract is lower and slower than Type II fibers.
Owing to the fact that Type I muscle fibers contract more slowly after receiving a neuromuscular impulse, they are referred to as “slow-twitch” muscle fibers.
Type I muscle fibers are recruited during sustained exercise like marathon running and distance running in general.
Type II Muscle Fibers
Type II muscle fibers are known as “fast-twitch” muscle fibers. In contrast to Type I muscle fibers, Type II muscle fibers contract much faster and more forcefully. They are powerful but fatigue rapidly.
Therefore, Type II muscle fibers are recruited for sprinting and high-speed, high-power activities like jumping and running uphill.
These muscle fibers are larger, contain very few mitochondria, and primarily generate short bursts of energy through anaerobic (without oxygen) metabolism.
Nearly all of our muscles contain some type of muscle fiber, but the relative percentage of the fiber types that constitute the muscle varies based on factors such as your genetics and the type of training you do.
Longer, slower runs will increase the percentage of Type I muscle fibers in your glutes, whereas sprinting and speed workouts increase the proportion of Type II muscle fibers.
Moreover, as mentioned, when supported by adequate protein intake and a moderate caloric surplus (usually at least 10% above caloric balance), running can build muscle mass by adding new muscle fibers.
Because Type II muscle fibers are larger and also more prone to grow in size, running fast, sprinting, speed workouts, and running uphill are especially effective ways in which running can increase the size of your glutes and make your butt bigger.
High-intensity exercise like sprinting and running fast also affects your hormonal profile, increasing the levels of anabolic hormones, which support hypertrophy, or muscle growth.
Therefore, running fast has the potential to make your butt bigger, and having a bigger butt might just mean that you run all that much faster.
How can you sprint for a bigger butt?
Studies show that the size (overall volume) of the gluteus maximus, the largest and most powerful glute muscle, is significantly larger in elite sprinters.4Miller, R., Balshaw, T. G., Massey, G. J., Maeo, S., Lanza, M. B., Johnston, M., Allen, S. J., & Folland, J. P. (2020). The Muscle Morphology of Elite Sprint Running. Medicine & Science in Sports & Exercise, 53(4). https://doi.org/10.1249/mss.0000000000002522
Moreover, between elite and sub-elite sprinters, the difference in volume of the gluteus maximus accounts for 34%–44% of the difference in season-best performance time in the 100-meter race. In simplified terms, in general, the larger the glutes, the faster the sprinter.
These findings were confirmed in another study5Tottori, N., Suga, T., Miyake, Y., Tsuchikane, R., Tanaka, T., Terada, M., Otsuka, M., Nagano, A., Fujita, S., & Isaka, T. (2021). Trunk and lower limb muscularity in sprinters: what are the specific muscles for superior sprint performance? BMC Research Notes, 14(1). https://doi.org/10.1186/s13104-021-05487-x, which again demonstrated the association between larger glutes and better sprint performance.
How Does Running Change Your Butt?
According to EMG and kinematic analyses6Lieberman, D. E. (2006). The human gluteus maximus and its role in running. Journal of Experimental Biology, 209(11), 2143–2155. https://doi.org/10.1242/jeb.02255, the major functions of the gluteus maximus during running are to keep the torso upright when you land, to control the swing of the airborne leg, to control the flexion of the hip upon impact, and to extend the thigh out for each stride.
The faster you run, the greater the involvement of the glutes, and the steeper the incline, the greater the hip extension workload that falls on the glutes.
Initially, when you accelerate from an easy jog to a faster run and even a relatively fast sprinting speed, the increase in speed is mostly achieved by increasing your stride length.
However, as you approach your maximal sprinting speed, increases in speed are accomplished primarily by increasing stride rate or running cadence.
This is achieved by the hip extensors—the gluteus maximus and the hamstrings—and the hip flexors—accelerating the hip and knee joints more vigorously while the legs are in the swing phase (not on the ground).
Again, this points to the fact that the faster you run, the more you are relying on your glutes.
The Takeaway: Can Regular Running Increase Glute Size?
In general, sprinting and uphill running can make your butt bigger when your protein and caloric intake are sufficient to support muscle growth. Distance running can make your butt smaller if you’re in a caloric deficit.
Why should you care?
Strong glutes are associated with a decreased risk of patellofemoral knee pain, or runner’s knee, and can make you a faster runner.
What exercise will give you a bigger bum?
Although running is a great cardiovascular exercise there are a number of strength training exercises that will help enlarge those gluteal muscles. Whether with barbells, dumbbells or just your bodyweight, squats, glute bridges, deadlifts, thrusters and step-ups.7Neto, W. K., Soares, E. G., Vieira, T. L., Aguiar, R., Chola, T. A., Sampaio, V. de L., & Gama, E. F. (2020). Gluteus Maximus Activation during Common Strength and Hypertrophy Exercises: A Systematic Review. Journal of Sports Science & Medicine, 19(1), 195–203. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039033/
These are great compound exercises that will work different muscle groups too, such as your quads and upper body.
If you want to add strength training into your running routine, consider working with a personal trainer.
To keep those glutes strong, check out our glute activation guide for distance runners!
