it depends on execution
the more upright the torso the more the knees will travel forward
an olympic full squat barely breaks paralel
because the knees travel so much forward and so the shin bone inclines to the front and lowers the knee height also and so the thigh bone ends up horizontal when knee is fully folded
this way the quads take a big load of the work almost like leg extensions
true story
many olympic lifters have phenomenal quads
but hack squats machine are more practical
perfect example, this is his full depth yet the thigh is parallel
massive load on the quads
I attribute Oly lifters having big quads to genetics. Let me explain.
If you take 1000 random people off the street of all different races, body structures, heights, etc... and line them up to choose the best swimmers. There will be about 100 which will be phenomenal swimmers with training, and the rest will be mediocre at best. Why? Because those 100 will have long limbs, tall and have the lung capacity for holding their breath and moving their muscles for a prolonged period of time. A guy who's 5'2 with stubby arms and legs has a snowball's chance in hell "swimming" his way to a swimmer's build (long limbs, long torso, etc...). My mom signed me up for basketball and swimming when I was in elementary school in hopes I would grow taller in the future
She saw that basketball players and swimmers were tall and figured they were tall because they play the sport, not the fact that they play the sport BECAUSE they're tall and are built for it.
So when people say "look at oly lifters and their huge legs, it must be because they're doing clean and jerks and snatches" I say that the reason they're good at clean and jerks and snatches (with heavy weights) is because they were built for it.
