Friday, September 7, 2012

D.I.Y. Static Contraction Device

Drew Baye had a post the other day about a homemade piece of equipment for static contraction hip belt squats that uses your own body weight against itself (post, pics and instructions are here).  I immediately recognized the potential for what he had built to be used for static contraction exercises for a bunch of other body parts/movements as well.  And like a little kid, I got all excited.  I've been using weights and a barbell for static contractions to good effect, but I really, really want something immovable I can push or pull against. 

Too bulky
So yesterday I headed to the hardware store and rounded up the pieces necessary to build this simple device. However, when I got home and merely stacked the wood in the proper position, I realized that it was going to be far too large and heavy for my liking.  If you have garage space or even an exercise room, I think it would be fine to make the thing via Drew's instructions, but having just a studio apartment, my wheels began spinning as to how to make a smaller and lighter version without compromising safety.  I believe I've come up with a hack that fits the bill nicely.

Instead of using three pieces of wood, as you can see in the pics, I'm only using one (I now have extra wood if anybody close by wants some).  The trick here is that I 'submerged' the nut and washer on the bottom side of the board so that it will be flush with the ground.  To do this I simply used a boring drill bit to make the necessary space.  As the board is a 2 by 12, I feel confident that there is plenty of 'depth' left for the eye bolt to screw into.  But just in case, I made sure to use a 1 1/2" diameter washer on both sides to spread out the forces over a greater surface area (look Mom I'm using my engineering degree!).  Theoretically, the larger the washer, the harder it will be to pull that eye bolt out, but I don't think they make washers much bigger for 1/4" diameter bolts and screws.  Anyway, if I do manage to rip that thing out, I'm signing up for the Worlds Strongest Man competition right away.
Top side with O ring and chain

Underside is flush (click to enlarge)

I plan on getting a hip/dip belt to use this thing like Drew shows in his post, and also for push ups (can you see how?) and dips, but for right now I just purchased about 7' of sturdy chain links.  With these, not only can I do biceps and triceps static holds, I can vary the angles just by selecting different chain lengths (via the O ring attached to the eye bolt).  With the long chain length I suppose I could also attach it to two dumbbells using a second carabiner.  The chain doesn't slide around the ez curl bar with the carabiner attached because there is a slight 'dip' in the center of the bar.  To make it even safer I could get an extra pair of stoppers and put them almost next to each other in the middle of the bar and then attach the carabiner in between them (see below).  I'm sure there are different ways to hook the chain up to your bar or device of choice, but safety must be a concern here as you don't want stuff slipping around under load.

Static contraction biceps curl

Static triceps extension

Attached to the ez curl bar

So there you have it.  A simple, and yet, very effective tool to play with.  I love little things like this.  I'll let you know soon how I'm getting along with my new toy.

By the way, from this pic here you can see that two years ago I was trying to do static contraction push ups at the playground using the structures.  This didn't work out so well as the bar 'dug' into my back too much.  At least the idea was there.


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