I have fibromyalgia and have been working out in the pool as I find I don't ache for days like I do when I work out with weights on land. I would like to find ou how much of my body weight I am actually lifting when I lift myself ou of the water by the rail. I do this in the deep end so I don't help myself with my legs and I do it in the corner as its easier with my arms at my sides then in front of me, if that makes a difference. I was quite happy to be able to do this at all as I am really out of shape. My therapist gave my about 69 or 70 exercises to do in the water. I know they do space traing in water to train for weightlessness but you still do have some weight don't you?

"I know they do space traing in water to train for weightlessness but you still do have some weight don't you?"

Yes, you still have some weight, but eactly how much you are lifting when you lift yourself out of water depends on your buoyancy, which depends on the percentage of body fat you are carrying. The lower your body fat percentage, the less your natural buoyancy will help. The short explanation of why this is, is that fat floats, while muscle sinks. Muscle is denser than fat.

To add to what DG said..

Your bouyance is determined by the amount of water you displace.

Let's say you weigh 190 lbs and displace 24 gallons of water. 24 gallons weighs 193 pounds, so you'll only weigh 2 pounds in water.

The problem is, as DG points out, not all people have the same density, and it's not very easy to determine your density.

Added to that, I assume that part of you is out of the water, an it sounds like the exercise involves lifting more of it out of the water. The part of you that is out of the water will no longer be contributing to your bouyancy.

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If you really want to determine your density (and with it, your bouyancy), you need to figure out your total volume. The best way is to see how much water you diplace, but it's probably not going to be easy to find a container you could do this with easily.

Actually, Phil Plait has a possible way to do this in your bathtub:

You can measure your own density. Fill a bathtub high enough so that when you get in you can completely submerse yourself. Mark the level of the water on the tub, perhaps with some tape (no doubt your parents won't like you scratching or marking the tub tile, even in the name of science). Then get in, submersing yourself as much as possible, and mark the water level again (note that it went up!). A friend would help a lot here. The difference in water level is your volume. You can measure that by taking a measuring cup and scooping away the water until the water level reaches the first mark you made. Keep track of the amount! Now, get on a scale and weigh yourself. Divide the weight in grams (one pound American is 454 grams) by the volume you found from the tub (one quart=4 cups=2 pints=908 cubic centimeters). That's your density! You should get a number that is close to 1 gram per cubic centimeter.

He's addressing this to a preteen, though. I don;t know aboiut you, but I'm too big (or my tub's too small) to do this.
http://www.badastronomy.com/mad/1997/float.html