What if everything you thought you knew about gym training preferences was just a hunch?
New data from over 230,000 training programs reveals the stark truth about which muscles men and women actually prioritize.
The findings confirm some stereotypes while crushing others entirely.
In a recent video analysis, Dr. Mike Israetel from Renaissance Periodization dove deep into unprecedented training data that exposes exactly how the two sexes approach muscle building.
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The Largest Training Data Set Ever Analyzed
Renaissance Periodization’s Hypertrophy app has collected over 1 million logged workouts since its 2023 launch. From this massive pool, researchers analyzed 231,741 total training mesocycles—203,086 from males and 28,655 from females.
This data set dwarfs anything previously available in exercise science, where most studies include only 20-50 participants. The sheer volume provides an unprecedented window into real-world training priorities.
Users selecting muscle priorities in the app choose between three options: emphasize, grow, or maintain. The question researchers wanted answered: which muscles do men and women choose to emphasize most?
What Men Actually Train: Upper Body Dominance
Chest takes the top spot for men at 64.5% emphasis rate. No surprises there.
But here’s where it gets interesting: the next four muscle groups are emphasized almost identically. Back ranks fifth at 61.3%, with biceps, triceps, and delts filling ranks two through four—all hovering in the mid-60s percentage range.
The real story with men here isn’t chest above all else, as much as it is upper body above all else, and damn near equally so for all of the major upper body muscles.
The Massive Drop-Off After Major Upper Body Muscles
Forearms rank sixth but drop dramatically to just 29.4% emphasis. That’s a 32-percentage-point plunge from back training.
Even more revealing: forearms still outrank every single lower body muscle by a significant margin.
Leg Day? What Leg Day?
Lower body muscles cluster together at dramatically lower emphasis rates:
- Quads: 22.2% (rank 7)
- Abs: Rank 8
- Glutes: Rank 9
- Hamstrings: 18.8% (rank 10)
- Calves: 15.7% (rank 11)
- Traps: 10% (rank 12)
Men prioritize legs and abs roughly one-third as often as they emphasize chest, back, delts, and arms.
Any denial of peg leg syndrome is now refuted by the data. Repent, you small-legged bastards.
What Women Actually Train: Lower Body Obsession
Women emphasize glutes most at 75.1%. Predictable, perhaps.
But the real story mirrors the male pattern: it’s not just about one muscle. Quads come in at 70% and hamstrings at 69.7%—creating a dominant lower body cluster that towers over everything else.
The more accurate story isn’t women equals glutes, it’s women prioritize their glutes, quads, and hams way more than the rest of their bodies.
The Chasm Between Lower and Upper Body
Hamstrings rank third at 69.7% emphasis. The next muscle down—abs at rank four—drops to just 43.5%.
That’s a 26-percentage-point canyon separating lower body priorities from everything else.
The next cluster includes most upper body muscles, ranging from calves at 30.4% (rank 5) down to triceps at 23.9% (rank 9). Shoulders, biceps, and back fill the middle positions.
Upper Body Gets Minimal Attention
Chest ranks dead last among major muscle groups at only 16.6% emphasis. Back, surprisingly, doesn’t fare much better despite ranking above biceps.
Forearms and traps receive barely any emphasis—4.1% and 2.1% respectively. These are essentially statistical rounding errors in a data set this large.
Women prioritize upper body muscles at roughly the same low rate that men prioritize lower body—an exact mirror reflection of training preferences.
How This Compares To Published Research
Research on everyday lifter priorities remains surprisingly thin. Most evidence comes from indirect sources rather than comprehensive studies.
A classic 1997 study by Mealey found men trained upper body significantly more than legs. A 2026 study by Baz Valatal showed back leading at 15-17 weekly sets, chest and shoulders at 12 sets, quads at 10 sets, with hamstrings lowest at 8 sets.
The outside literature is mixed, indirect, and limited. But that’s where thankfully the RP data set can help.
Research from De Silva and colleagues comparing physique athletes showed identical patterns: men performed far more upper body work, especially chest and back, while women emphasized lower body exercises like squats, hamstring curls, and hip adductions.
The RP data doesn’t represent some isolated phenomenon—it validates and expands what smaller studies have suggested for years.
Why These Patterns Exist: Evolution Meets Iron
Men naturally possess bigger, stronger upper bodies than women. Women, relative to body weight, have similarly developed legs compared to men.
When both sexes enter the gym, they appear to amplify these existing differences rather than balance them out.
My take is that men love a jacked upper body because it’s a signaling mechanism for strength and dominance in our primate brains. And women love a jacked lower body because that’s a signal for health and capability to our primate brains.
A developed lower body with a small waist creates the waist-to-hip ratio that nearly every culture finds attractive. Upper body development signals strength and capability.
Cultural influence certainly plays a role, but appears to have only marginal effect. Evolutionary psychology drives the fundamental patterns observed across different populations and data sets worldwide.
Trends Aren’t Laws: Train What You Want
These findings describe trends, not prescriptions. Big trends, certainly—but trends nonetheless.
Plenty of men prioritize legs, glutes, calves, and abs. Many women emphasize chest, back, arms, shoulders, and traps. Both approaches are completely valid.
We are not saying men must train this way or women must train that way because that would be stupid, boring, and frankly way less fun than watching people build whatever weird, beautiful, personally satisfying meat sculpture they want to walk around the planet inside.
The data simply reveals that when given access to modern training equipment and knowledge, men and women tend to use that technology differently—in ways remarkably aligned with evolved aesthetic preferences.
Your Priorities Are Valid
If you’re a woman training legs intensely, you’re extremely normal. If you’re a man prioritizing chest, arms, shoulders, and back over legs, you’re also extremely normal—surrounded by millions doing the same.
Most men still train legs. Most women still train upper body. They just don’t emphasize them as heavily.
Don’t let anyone guilt you into thinking your priorities are wrong simply because they match a stereotype. Sometimes stereotypes exist because millions of people genuinely want similar things.
Train for the physique you actually want. Train muscles you genuinely care about. Train in ways that make you proud when looking in the mirror and keep you showing up consistently.
The data doesn’t dictate your choices—it simply reveals what happens when humans are free to pursue their individual aesthetic goals.
