Here is another link to a reputable site. Go about halfway down the page.
http://skepdic.com/akinesiology.html
Bottom line is that there is no evidence whatsoever that this method works or has any basis in science. There is not much need to debunk something that is so absurd on its face.
It seems like just the fact that your hand is closed might be what is doing the trick. I just tried it on myself and my wife, anyway, and for both of us it seemed easier to push the arm down when the hand was closed.
-FrL-
As Contrapuntal has said, the ‘result’ depends largely on the effort that the tester is making to press the arm down. It is normally fairly easy to press down anyone’s outstretched arm, because the leverage is all in favour of the arm going down. If the tester applies less force than usual, the arm stays up.
However, a more accurate answer to ‘why does it appear to work’ is that it doesn’t. Never has, never will. Not if you apply a proper, well-controlled test. Take someone who believes in applied kinesiology, let them test a patient using AK and ‘diagnose’ that this person is allergic to, say, peanuts. Let this test be conducted in the usual way (for AK) whereby the tester knows when the peanuts are present and when they are not, and therefore knows what the result is supposed to be. Fine.
Now line up five opaque, sealed containers, one containing peanuts and the rest containing a harmless substance indistinguishable in terms of weight and other tactile feedback. Mix these at random and allow the AK practitioner conduct all the tests she wants with the patient to determine which container actually contains peanuts. The practitioner will never achieve any statistically significant result better than chance, because AK doesn’t work. If you find a practitioner who can score better than chance, they may still have a chance at Randi’s million dollar prize (although the rules of the challege have changed recently) but they will certainly have a shot at a Nobel prize, lasting fame and possibly great wealth, as they will have managed to overturn a great deal of what we thought we knew to a very high degree of confidence about physics, medicine and successful treatment (medicinal and therapeutic) of allergies and related conditions.
Anyone who sincerely believes that are doing something effective when they ‘use’ AK is either seriously deluded, or hasn’t a clue what constitutes good evidence and good reasoning. Some practitioners may be aware that AK has no actual diagnostic validity, but don’t mind playing a little trick on some patients because they hope the patient will respond to the placebo effect, or because it’s a good way to secure the patient’s confidence and co-operation en route to prescribing something that does work. Some practitioners know it has no actual value but use it anyway, just as a shabby, shameless way to exploit other people for money. I apologise if this comes as a shock to anyone.
A skin test by an actual allergist. Or a blood test I am not sure. I have a referrall to see an allergist later this month, meanwhile I have Benadryl on hand and am reading the lables.
Well, the prick tests showed I am allergic to peanuts, ragweed, maple and two kinds of mold. (Curvularia and Ustilago) Pretty well, yeah, I have allergies year round. :smack: 
I’m more allergic to the short ragweed than to the peanuts. I’ll be taking the therapy shot course to increase my tolerances. There is nothing they can do to help a peanut allergy though, so I must avoid peanut proteins. Which, means I will be eating very little chocolate now. I’m a chocoholic. I’ll be posting a new topic asking about companies who keep their peanut production entirely seperate from their products that have no nuts next.
Thank you again to all who replied and helped me read up on the scam. 
Unfortunately the positive result for a peanut allergy will only confirm the doctor’s belief in akinesiology.
Yeah, I know. :mad: I said “It sucks to give him this victory!” to my husband in the car on the way home. :smack: But, at least now I know and I can stop tempting fate. I just realized I can never have another Cherry Mash again, nor can I have a Bar None candy bar if they come back. (And there is a movement to bring back the original, non-caramel version back.)
{{{{Zabali_Clawbane}}}}
That sucks! I’m so sorry! I can tell you though, as another chocoholic, that I dated someone with a serious peanut allergy for about 6 months, during which I had to not eat any peanut-related food lest I give him the kiss of death (quite literally). At first I really missed my peanut M&Ms and such but, after a while, I found I didn’t miss them at all. I also have a serious potato allergy that I have to work around, but it’s become routine, as this will eventually become for you. Good luck to you!
How allergic are you Zabali_Clawbane? I understand that some people are affected by very small quantities of peanut residue, but does that necessarily mean you are too? Just because you can’t eat peanuts, does that mean you really can’t eat chocolate made in the presence of peanuts?
Disregard that, I’ve just read your other thread and I see that it is best to avoid the stuff altogether.