Looking back on my logs, back in summer 2018 I was single leg pressing 440lbs x 10 on each leg. The year before that, I was leg-pressing 775lbs 3 set of 5, in my 40s. I know of smaller guys who can do more than that.
One thing to remember is that, due to the angle of the sled, you aren't lifting that much weight vertically off of the ground. If the sled is 45 degrees, you are feeling about 72% of the weight (plates plus sled weight) on your feet.
That may still seem like a lot when compared to squatting, but know that when a person squats, they are actually squatting MORE than the plates and the bar. They are also adding their upper body weight to the mix. So, if a 200lb guy is squatting 150lbs on his shoulders, his legs are squatting 150lbs + 100lbs of upper body (round number for conversation's sake) for a total of 250lbs of load on his legs. Now, if he wanted to recreate the same level of load on the leg press machine, he'd have to have the sled and weights weigh about 350lbs.
In his log book, he'd note:
Squat: 150lbs.
Leg Press: 350lbs
And they'd essentially provide the same amount of load on his legs.
That is why leg press numbers seem so much higher than Squat numbers. No one is getting over by doing leg press. It's just a lot of not-so-obvious arithmetic going on. Basically, when you squat, you are squatting more than the numbers on the bar and when you leg press, you are pressing less than the numbers on the bar
