Leg muscles are indeed endurance-oriented with ~58% slow-twitch fibers, but training them twice a week with lighter weights won't actually grow more muscle. Studies found more frequency boosts strength but not size—so heavy once a week might still be the way to go for growth. https://s.fitbodyscience.com/uPPC4Y
There's disagreement
Studies point in different directions — there's no clear consensus yet.
The idea that working legs twice a week with lighter weights builds more muscle than one killer session isn't backed by research.
When researchers looked at how often people trained, they found that going more often helped strength but didn't lead to bigger muscles—so the muscle growth part of the claim doesn't hold up. Other research shows that leg muscles do have more slow-twitch fibers (about 58%) compared to arms (40%), which supports the idea that they're built for endurance. So the fiber-type point is correct, but the training advice to maximize hypertrophy with lighter, more frequent sessions isn't supported by the studies we have. The evidence conflicts: one study found more frequency boosted strength but not size, while another agreed that frequency didn't help muscle growth, directly contradicting the claim.
Your legs are indeed endurance muscles, but if you want bigger quads, the research doesn't back going lighter and twice a week over a single heavy session.
Click any claim to see the full scientific analysis
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.