Ok, let’s debate.
Remember the original Nautilus leg press machine? Jones, through the use of the cam, tried to mimic the natural strength curve of the pressing movement of the legs, i.e. how you are so much weaker in the full squat position and the resistance started to increase as you pushed forward allowing maximum load, or as close to it, during the full range of motion through the use of the cam.
With the barbell squat, you are limited to the amount of weight you can use when you are at the weakest position, in the bucket, the full squat position. So in practice, it is very hard getting out of the bucket and then it becomes relatively easy to lock out as you get so much stronger, or rather in a much stronger position, as you get closer to the top.
Furthermore, in the squat, the resistance is placed on the top of the spine, and has to travel down the very weak and unstable path of the spine and vertebrates which are designed more for mobility than stability, going to the lower back, then finally the strong heavy bones of the hips and legs.
With the leg press the resistance starts at your strongest foundation only having to travel past the large and strongest bones and joints of your femor and hips.
This is not to mention the instability inherent in balancing and moving with a heavy bar across your shoulders and spine and trying to maintain proper posture as you start to fatigue. With the leg press your body is naturally held in a stable position.
Exercise should enhance strength and functional ability and I don't think it is a coincidence that many, if not most, have to quit doing barbell squats as they get older because of the damage and unnatural strain it puts on the body. There's a lady in our gym in a wheelchair that is still able to do the Hammer or Hoist leg press.
