Quite often through these boards I often see the question how come I can leg press much more than I can squat.
The answer is pretty simple and can be explained by 3 reasons:
(1) When using a typical sled type leg press you are in fact only moving the equivalent of 0.707 x weight because the leg press itself takes some of the weight.
(2) When squatting you are actaully squatting the weight of the load PLUS YOUR OWN BODYWEIGHT. When you leg press you sitting down you you don't actually have to lift your own weight.
(3) The leg press moves in a fixed path of motion, so stabilizers are less involved meaning you can shift more weight. The same principle applies when you consider the weight of DBs you can press compared to say benching on a smith machine.
I have worked out a rough formula to equate the two. I was bored walking home from the gym as my ipod ran out of battery.
Max Squat =~ (Stabilisation Factor x ((Max Leg Press x 0.707)) - Bodyweight
I found that the Stabilisation Factor will probably lie between 0.8 and 0.9 for most people, and will depend on body your body mechanics and how developed various stabilizer muscles are. For me it is approx 0.85.
Max Squat =~ (0.85 x (340 x 0.707)) - 85
In theory my max squat should be about 119 (its 115kg)
Or looking at it from the point of view of the amount you can leg press
Max Leg Press =~ ((Max Squat + Bodweight) / Stabilisation Factor) / 0.707
If anybody has any critique of this it would interesting to find out, or indeed if people work out their max theorised Leg Press from there Max Squat etc.
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07-31-2009, 03:14 PM #1
- Join Date: Dec 2008
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Why can I Leg Press more than I Squat? ...Answered
2010 Log: http://forum.bodybuilding.com/showthread.php?t=121533211
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07-31-2009, 03:19 PM #2
i can full range leg press over 800 lbs.
I can squat (with no wraps) 415.
Does that work with the formula?
I have seen guys who cant squat 315 load the entire leg press and get some reps in.
Another factor for leg press is tha tits really easy to do partial reps, knee bends really. I see it all the time.
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07-31-2009, 03:19 PM #3
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07-31-2009, 03:26 PM #4
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07-31-2009, 03:28 PM #5
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07-31-2009, 03:32 PM #6
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07-31-2009, 04:21 PM #7
Are we assuming a 90 deg. leg press here? If not you would have to factor in the angle also I believe.
Pretty good equation you came up with. Comes out pretty accurate for me too. I assumed I can squat 145kg for atleast 1 rep (I can do 140 for 3 reps), and I have leg pressed 340kg for 6 reps on the leg press previously. The equation said I could lift 404kg for 1 rep. ]
However I know some guys who can squat over 400lbs but struggle on the leg press.BRB... cutting for 12 weeks
Bench: 145kg (320lbs) x 1 <<< NEW PR August, 2009
Deadlift: 210kg (463lbs) x 1 <<< NEW PR December, 2009
ATG Squat: 165kg (364bs) x 1 <<< NEW PR December, 2009
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07-31-2009, 04:22 PM #8
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07-31-2009, 05:21 PM #9
- Join Date: Feb 2008
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I wrote this up a while a go explaining the short falls of the Leg Press. You might like it OP:
Why the Leg Press Sucks and How to Fix it! Video & Pictures
http://forum.bodybuilding.com/showth...ighlight=bandsLast edited by REPS-Forum-Rep; 07-31-2009 at 05:23 PM.
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07-31-2009, 08:18 PM #10
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07-31-2009, 09:07 PM #11
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07-31-2009, 09:37 PM #12
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07-31-2009, 10:56 PM #13
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07-31-2009, 11:08 PM #14
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You don't have to maybe I was on a slide with less resistance. Maybe Ronnie is capable of a lot more. I mentioned in another thread that given the estimates I've seen from my own squat to leg press ratios, as well as those of other guys I've known who leg press a lot, that Ronnie could probably leg press well over 3K if anyone made a slide for him to do it on. I've seen 115 lbs women leg press 800 lbs knees to chest. Anyone who can squat 405 atg, can most definatley leg press 1500-1600 for reps if they spent a month working on it twice a week. I bet Ronnie could do 3k+ on the leg press for 10 reps if he had the equipment available, and he had a little time to get used to the weight on the slide. He only works 2200 because that is what is available, and he probably doesn't normally work 20+ reps for legs.
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08-01-2009, 02:46 AM #15
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08-01-2009, 03:28 AM #16
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08-01-2009, 08:35 AM #17
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08-01-2009, 08:43 AM #18
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08-01-2009, 08:44 AM #19
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08-01-2009, 08:45 AM #20
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08-01-2009, 08:47 AM #21
- Join Date: Jul 2008
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No, because the component of the weight acting down the lift to your legs is the sine of 45Degrees, or cosine for that matter, which is 0.707.
Also, if one guy said i can do 6 reps at 200kg down to my chest, while another says i can do 6 reps to 90 degrees, who would you say is stronger? I suppose it also depends on user preference.
I prefer to go ass to grass with squats and knees to chest with legpress.Last edited by mcgrimes; 08-01-2009 at 08:53 AM.
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08-01-2009, 11:35 AM #22
Nice simple formula; I like the way you incorporate a 'fudge factor' in to account for some slop. Some observations:
1) Our full body weight isn't being squatted when we do squats. Weight below the knees is nearly negligible and weight from knees to hips is lifted in a lever movement. Not that this decrease in body mass is worth taking into account for a simple equation (it can be incorporated into the stabilization factor).
2) I instinctively feel like the equation will work better for squat->leg press calculations rather than vice versa. I say this mainly for people who don't squat (the weak) and would have a terribly low stabilization factor.
3) ROM on these has to be crucial. People that squat to parallel will likely have a different result from the equation than those who squat ATG (unless depth on the leg press correlates).
4) I think an interesting way of using this could be to calculate your 'stabilization factor', it's the only variable in your equation that can't be determined directly. If you find a max on squat and leg press (5RM, 10RM?), you could get this number. Not that it would do you too much good..maybe a new e-stat?
5) For heavier weights, the equation may break down. A heavy compound movement (squats) becomes more difficult to continue to add weight to than a more isolated one (leg press).
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08-01-2009, 11:42 AM #23
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08-01-2009, 12:11 PM #24
- Join Date: Jun 2009
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Right, I am thinking this formula is fine for people who are a bit weaker, but I've noticed it becomes very inaccurate for men who can deep squat over 315 lbs and women over 200 ish. I've had a friend who could squat 315x6 but do full ROM leg presses with WELL over 1k, and a woman with a 185 max squat do 800 lbs on the leg press. For stronger individuals I would say the leg press, if they spend some time working on it (I did for about 6 months because another bodybuilder convinced me doing heavy squats all the time would thicken my waistline up so I stopped squating for 6 months because of this rediculous advice and started leg pressing twice a week and got up to 2k for my worksets before just going back to squats) is something in the range of 3.5-4.5x their squat.
In any event I feel the squat is a better movement having used both extremely heavy squats and leg presses seperately as a primary mass builder. My thigh development didn't signifigantly improve when I dropped squats for heavy leg presses, however it did once I stopped leg pressing and went back to squats.
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08-01-2009, 02:31 PM #25
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