Small range of movement

Could someone please explain to me....

ive been watching a few Ronnie vids on youtube... pretty much every exercise he does is with the smallest range of motion.

Is this cos hes so big is range of motion is limited? or because the whole world is watching that he doesnt want to train properly?

everything that i have learnt, suggests that a full range of movement is the way to go to stimulate the most muscle fibres.

please explain

Some range of motion does go away when you get big and don't keep stretched out properly. There's probably a point where you can be stretched all you want, but the size will get in the way. As far as Ronnie is concerned, it's probably for both reasons you stated.

yeah watching him do leg presses his range of motion is like half of mine but he can not go any lower, his legs are too big and so is his chest cavity

ive narrowed my range of motion in alot of my movements and I'll tell you why...
over the years I have grown which contributes to some of the reduced ROM, but the main reason is that I train smarter.
Alot of the "weight training 101" basics tells you a full ROM is best...which it is if you're a beginner. But I have very long appendages and am capable of a much larger ROM than that which actually targets my muscles. I can do military presses and the middle half of the movement is all I do. I can lockout and hit nothing but triceps...I can go down and touch my chest and only hit my upper chest...but Im doing a shoulder exercise and want to mainly target that muscle group.

more advanced lifters can actually feel the moment in a movement where the stress goes from the intended target muscle to other muscles. I use that feeling to judge my ROM.

At certain times a short range of motion will help, but overall I'd say you want to get as much as you can, but when you're that big, I'm sure his ROM is hindered