Doing partial reps with extended muscle stretch and full reps with normal movement build your arm and thigh muscles about the same amount over 12 weeks — neither one is clearly better than the other.

Doing partial-range weight exercises with a longer muscle stretch can build arm and thigh muscles just as well as doing full-range exercises, as long as you’ve been training for a while and do it for 12 weeks.

If you're already strength-trained and do upper-body workouts for 8 weeks, it doesn't matter much if you lift all the way up and down or just do part of the motion—your muscles grow and get stronger about the same either way.

Even if you don’t move through the full range, doing the exercise where your muscle is stretched the most (like halfway down in a squat) builds more muscle than doing it where the muscle is bunched up (like a shallow squat).

Whether you train both legs together or one at a time, your thigh muscles grow about the same amount after 12 weeks of heavy lifting.

The lower part of the thigh doesn't get noticeably bigger after 8 weeks of any of these training styles, even if the upper and middle parts do—meaning muscles don't grow evenly everywhere.