There is no reliable physical evidence to confirm that low-volume, high-intensity training produces better muscle growth than other training methods, despite what some people claim anecdotally.

People who start working out with thinner thigh muscles tend to grow them bigger faster than those who start with thicker thighs—but how thick your muscles are at the beginning doesn’t tell you much about how much they’ll grow overall.

Lifting heavy weights and lifting lighter weights can both build muscle just as well for different people, as long as you do the same total amount of work. It suggests that how hard you push might not be the main thing that matters for muscle growth.

Lifting weights with just a few heavy reps or many lighter reps gives about the same muscle growth when you do the same total work.

When you do strength training with your muscles stretched out (like in a full squat versus a half squat), you tend to build more muscle. But this works better for people who are new to training than for people who already lift weights regularly. Scientists may have originally overstated how big this difference really is because studies showing bigger effects get published more often than studies showing smaller effects.

If young guys lift weights for eight weeks—whether they go heavy or do more reps—they’ll likely build muscle in their upper body and back, and that can be seen with ultrasound scans.