If new guys lift weights for 15 weeks using only part of the movement—focusing on the shorter muscle position—they build more muscle size in that specific area and get stronger at certain joint angles, according to this claim.

If new guys lift weights for 15 weeks using full movements, their leg muscles get longer and stronger at the fiber level compared to doing shorter movements—even if they spend the same amount of time lifting.

If you're new to lifting weights, how far you move during each rep — like doing full squats vs. half squats — changes how your muscles adapt, even if you spend the same total time lifting.

You can get just as strong by pushing weights up as by lowering them slowly—even if lowering them doesn’t make your muscles sore or damaged.

Not all muscles grow the same way when you move through different ranges—some might need bigger movements than others. So, telling everyone to do the same type of lift might not work for every muscle.

Whether you use machines that change resistance as you lift or keep the same weight all the way through, after 20 weeks of training, healthy men gain about the same strength and muscle size either way.