Homemade leg press

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imported_dkm1987

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Navigator asked questions concerning my home made leg press so let me explain and I'll post some use pics here.

It is made of galvenized plumbing pipe 1" and 3/4" so far I have had it Loaded to 365lbs, my 5 RM, it uses 4X4 treated lumber for the base. It is a leverage type press.

I will post pics this evening since I am starting my new cycle anyway.
 
Nice, but I can't help thinking that the load decreases as your legs straighten (& your bio-leverage becomes more favourable); maybe adding some chains would "equal" it out...
 
Elaborate on the chains, please, why, where, I have noticed that as my legs straighten the tension shifts to the glutes, which is fine since I want them worked. I do not lock my knees out so I keep tension applied, I did in the pics for demonstration purposes only. Any help you can give to make it better would be appreciated. :D
 
Hi dkm1987,
Thanks very much for posting all this info about your homemade leg press. It's very cool!!! I will make my own, eventually.
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I think your glutes get worked because of the angle between your torso and the direction your legs are pressing when they straighten. If you were sitting upright, so that your straightened legs are closer to 90 degrees relative to your torso, I think your glutes would get less work.

I think the_dark_master was suggesting attaching long chains to the weighted bar with most of the chain initially lying on the ground. That way, as you raise the weight, you also raise more chain off the ground, and thus the load gets heavier.

The_dark_master's suggestion may be a good idea for another reason, too. Since the load is supported below by the hinged bars, as you raise the weight, the hinged bars support an increasing portion of the weight. This leaves less tension on your legs, and it occurs in addition to the improvement in your bio-leverage as your legs straighten. The increasing weight of the chains could counteract this.
 
[b said:
Quote[/b] (navigator @ Aug. 22 2004,5:01)]
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[b said:
Quote[/b] ]I think your glutes get worked because of the angle between your torso and the direction your legs are pressing when they straighten. If you were sitting upright, so that your straightened legs are closer to 90 degrees relative to your torso, I think your glutes would get less work.
Click to expand...

I fiqured as much, which is why my next revision is to have an adjustable angle bench to bring my torso more perpendicular to my legs. But I do need the glute work anyway
;).

[b said:
Quote[/b] ]I think the_dark_master was suggesting attaching long chains to the weighted bar with most of the chain initially lying on the ground. That way, as you raise the weight, you also raise more chain off the ground, and thus the load gets heavier.
The_dark_master's suggestion may be a good idea for another reason, too. Since the load is supported below by the hinged bars, as you raise the weight, the hinged bars support an increasing portion of the weight. This leaves less tension on your legs, and it occurs in addition to the improvement in your bio-leverage as your legs straighten. The increasing weight of the chains could counteract this.
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Ahhhh I see said the blind man, very very good point.
 
Yeah, I know what you mean about the glutes--I'd like that too. I'm brainstorming a leg press device that I can interface with the my existing adjustable bench, where when I press with my legs the device lifts a load upward. Perhaps, a hinged lever of some sort. When I have something definitive, I'm be sure to post it here.
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I'll tell you, though, a great thing about your device, dkm1987, is since the load is supported from below, it won't fall on you if there's a malfunction. With the weight supported above you, you could get killed if there was a problem.
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[b said:
Quote[/b] (navigator @ Aug. 22 2004,6:40)]
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My first design was a vertical press, but since I had used two rails for stabilization they kept getting stuck, unless you lifted the load PERFECTLY level, it hurt like hell when it got stuck, so I changed it. I would be glad to send you a quick and dirty drawing of it, and also another idea of mine which would incorporate by adjustable bench and a cable system.
 
Hi dkm1987,

Sure, that'd be great!!! I suppose you could either post the drawings here or email them to me. Either way, I'd love to see your latest & greatest designs.
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Hi dark_master,

That's pretty cool! I like the L-shaped lever the best. I think I'd attach the lever to the cage at the corner of the L, though. That would minimize vertical motion of the foot support as the lever moves. I think I'd also pivot the foot support, too, so that your feet aren't forced to rotate as you straighten your legs.
 
[b said:
Quote[/b] (navigator @ Aug. 23 2004,1:57)]Hi dark_master,
That's pretty cool! I like the L-shaped lever the best. I think I'd attach the lever to the cage at the corner of the L, though. That would minimize vertical motion of the foot support as the lever moves. I think I'd also pivot the foot support, too, so that your feet aren't forced to rotate as you straighten your legs.
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Dark Master, the sleeve you mention in the drawing, from what I noticed on my vertical press was it would bind unless the tolerance was very close and encompassed a long section of the support, just a heads up. Also the cushion for your back should be at an angle of around 7 to 15 degrees, for proper hip support and alignment, hips slightly higher than head.

Heres what I had envisioned
 
[b said:
Quote[/b] (Dont_quit @ Aug. 23 2004,1:36)]Wow that's pretty cool dkm. Nice job.
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Thanks, your Leverage dip is great I plan on adding one to my equipment based on your plans.
 
[b said:
Quote[/b] (dkm1987 @ Aug. 23 2004,1:32)]Heres what I had envisioned
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Hi dkm,

That's a pretty cool idea!!! I think it includes everything I've thought of myself, also. I'm trying to think of simple ways to incorporate this type of design into my own cage system. :D
 
Point taken about the L shaped lever, however; the reason for the positioning of the pivot down the lever-arm, is two-fold.
This position allows for two leverarms, one either side of the supporting upright, which inturn "sandwich" the shorter footplate arm and makes the joint sturdy.
The position of the pivot also allows for greater movement of the footplate, without lengthening the footplate leverarm.
With regards to the vert leg press, this is actually open ended for quick mounting on the uprights (safety is via a bolt either end, which also supports the chains) As I envisaged the actual crossmembers to be timber running on 2"x2" metal verticals, a little silicon grease should stop them from jamming.
As we are talkin' homemade equipment, I thought it better to throw in a few "do-able" suggestions; be it made in wood or metal. It's often more fun making the prototype, and educational, if you have to "fill in" the blanks...
 
Dark Master, nice job guy, I like it. How proficient are you with pullies and the math associated. Reason: If you use your design and to diminish the needed weight on the power pole, could you use a multiple pulley system to take it from a 1:1 to somewhere in the 3:1 range?
 
Hey dark_master, that's sweet!!! I've thrown together a cheap version of this by using the seat and rail on a rower and a dipping belt--still experimenting, though.

Since there's a limit to the weight the upright can handle, we definitely need to ratio things to diminish the needed weight on the upright. I think a multiple pulley system will increase the weight needed on the upright (by increasing the mechanical advantage experienced by our legs). So, I think we need to ratio the torques on the pivots between the foot paddles and the levers attached to the cable. That is, increase the length of the lever attached to the cable and decrease the length of the lever attached to the foot paddles.
 
Like thisLeg Press
Take your eyes away from the model and look at the pulleys on the actuating arm of the press. Also note the ratio description on the bottom of the page.

Is this correct, I guess I can find a calculator that will tell me, if it is then the weight pole can actually be loaded with less amounts and you can still get the same effect.
 
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