If you’ve ever looked in a fitting room mirror and wondered why your backside looks more like a post-it note than a peach, you aren't alone. It's frustrating. You’re putting in the work, maybe hitting the gym or watching what you eat, but the "square bum" look persists. People often search for square bum before and after photos hoping for a miracle transformation, but the reality is a mix of bone structure, fat distribution, and how you actually move your body.
It’s not just about vanity. The shape of your glutes often tells a story about your pelvic health and muscle recruitment.
Let's be real: some of us are just born with a "H-shape" pelvis. If your hip bones and your trochanter (that bony bit on the side of your femur) are aligned a certain way, you’re naturally going to lean toward a square silhouette. But that doesn't mean you're stuck. There is a massive difference between "genetically square" and "functionally flat."
The Anatomy of the Square: It’s Not Just Fat
Why does it happen? Honestly, it’s usually a combination of three things.
First, look at your iliac crest. That’s the top of your hip bone. If it’s high and wide, the muscle has a longer distance to travel to "fill out" the space. Second, consider the "gluteal shelf." This is the fat distribution at the top of the buttocks. If you carry more weight at the waist—the classic apple shape—it creates a visual line that squares off the top.
Then there’s the muscle itself. Or the lack of it.
The gluteus medius and minimus sit on the sides. If these are underactive, you get "hip dips." While hip dips are totally normal and mostly skeletal, a lack of muscle volume makes them look more pronounced. When people look at a square bum before and after, the "after" is almost always a result of hypertrophy in these specific areas, not just losing weight. In fact, losing too much weight without building muscle often makes the square shape more obvious because you lose the padding that rounded things out.
Modern Life Is Making Us Boxy
Gluteal amnesia is a real thing. Dr. Stuart McGill, a world-renowned spine biomechanics expert, has talked extensively about how our sedentary lifestyles lead to "sleepy" glutes. When you sit all day, your hip flexors get tight. This creates a reciprocal inhibition—basically, your brain forgets how to fully fire the glute muscles because the muscles on the opposite side are so jammed up.
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The result? Your butt flattens. It squares off.
Think about your posture right now. Are you tucking your tailbone under? This "posterior pelvic tilt" is a huge contributor to the square look. It hides the natural curve of the lower back and pushes the glutes inward. You can see this in many square bum before and after comparisons; often, the person hasn't even gained muscle, they’ve just fixed their pelvic alignment.
Moving more isn't always the answer if you're moving wrong. If you run or walk using only your quads and hamstrings, your glutes stay dormant. They atrophy. They square.
What a Realistic Transformation Looks Like
You’ve seen the Instagram posts. A girl goes from a flat, square shape to a massive, round shelf in "two weeks."
It’s fake.
True muscle hypertrophy takes months of consistent, heavy loading. A real-life square bum before and after timeline is usually six months to a year. In the first few weeks, the "after" is usually just a pump—increased blood flow to the muscle. By month three, you start seeing the "corners" fill in as the gluteus medius grows.
- The 0-3 Month Mark: Improved posture. The squareness softens because you aren't slouching.
- The 6-Month Mark: Actual muscle fiber growth. This is where the "side butt" starts to appear.
- The 12-Month Mark: Significant change in fat-to-muscle ratio.
I’ve seen clients get frustrated because they do 100 bodyweight squats a day and see zero change. Squats are great, but they are primarily a gluteus maximus (the big meaty part) exercise. To fix a square shape, you have to target the "abductors."
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Exercises That Actually Change the Shape
If you want to move the needle on your square bum before and after journey, you need to stop obsessing over the scale and start obsessing over tension.
The Power of the Lateral Plane
Most people only move forward and backward. To round out a square shape, you have to move sideways. Clamshells are the classic, but they’re often done wrong. You shouldn't just be flapping your leg. You need to feel the burn in that upper-outer quadrant of your hip.
Weighted cable abductions are the gold standard here. By pulling your leg across your body and then out to the side, you put the glute medius through a full range of motion.
Hip Thrusts are King
Bret Contreras, often called "The Glute Guy," has popularized the hip thrust for a reason. Unlike the squat, which has the most tension at the bottom when the muscle is stretched, the hip thrust has the most tension at the top when the muscle is contracted. This is vital for "lifting" the shape and breaking that square profile.
But don't just go through the motions. You have to squeeze. Hard.
Deficit Lunges
If you want to target the "tie-in" where the glute meets the hamstring, deficit lunges (standing on a small platform) allow for a deeper stretch. This extra range of motion signals the body to repair and grow more muscle tissue in the lower portion of the glute, which helps transition the square shape into something more tapered.
Why "Toning" is a Myth
You can't "tone" a square bum. You can only build muscle or lose fat.
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Usually, the square look comes from a "skinny fat" state—low muscle mass combined with a bit of subcutaneous fat on the hips. If you just diet, you’ll end up with a smaller square. If you just bulk, you might end up with a larger square. The magic happens in "recomposition."
Eat at maintenance calories. Eat a lot of protein—aim for about 0.8 to 1 gram per pound of body weight. Lift heavy things.
I know, it sounds like gym-bro advice. But the biology doesn't lie. Muscle is dense. It’s what provides the "round" structure underneath the skin. Without it, you’re just working with the shape of your skeleton.
Nutrition and the "Shelf" Effect
What you eat determines where your body stores energy. While you can't spot-reduce fat, you can reduce systemic inflammation which often shows up as bloating around the midsection. This bloating exacerbates the square look by hiding the waist-to-hip ratio.
A diet high in processed sugars can lead to higher cortisol levels. High cortisol is scientifically linked to increased abdominal fat storage. By cleaning up the diet—focusing on whole foods, fiber, and healthy fats—you often see a square bum before and after result that looks like weight loss, but it’s actually just a reduction in inflammation and a shift in body composition.
Don't Forget the "Glute Medius Kickback"
This is the secret weapon. Most people do kickbacks straight behind them. To round out a square bum, you should kick back at a 45-degree angle. This aligns with the fiber orientation of the gluteus medius.
It feels weird at first. You might look a bit like a dog at a fire hydrant. But the tension it creates in that "hollow" spot of the hip is unmatched.
Actionable Next Steps to Change Your Silhouette
Stop looking at edited photos on social media. Half of those square bum before and after shots are just clever lighting or a high-waisted legging trick. Instead, focus on these tangible moves:
- Check your pelvic tilt. Stand sideways in a mirror. If your lower back is totally flat and your butt is tucked under, start working on hip flexor stretches and "anterior pelvic tilt" awareness.
- Prioritize three "side" movements. Add side-lying leg raises, monster walks with a band, and cable abductions to your routine at least twice a week.
- Eat for growth. If you aren't eating enough, your body won't build the muscle needed to fill out the square. Prioritize protein at every meal.
- Track your measurements, not just the scale. A square bum might transform into a round one while the scale stays exactly the same. Measure your hip circumference and your waist-to-hip ratio.
- Be patient. Muscle takes time. If you’re consistent with heavy lifting and proper form, you’ll see the squareness start to soften in about 12 to 16 weeks.
The "square" isn't a flaw; it's just a starting point. Whether it's your bone structure or your sitting habits, you have the tools to shift that silhouette through targeted hypertrophy and postural correction. Focus on the function, and the form will follow.