Hi houstongirl500 (what a funny name of someone trying to increase his dick size ;-)).
First things first: Welcome to Thunder’s Place :)
Now the actual answer:
Well no, I don’t think those studies were done bone pressed.. In any case people on TP tend to bone pressed measurements, not to compare their size with others (well mostly ;) ), but to check for their personal gains.
In short: Just measure the same time way everytime and you will have a good tool to help finding the exercises that work best for you :)
About jelqs et al:
Generally there is no need to be scared really.. unless you are pressing the CS (below your penis leading to the head), of course.
This can damage the nerves (important for feeling anything in/on the glans and shaft), if done very improperly, permanently.
So you make sure you don’t damage your nerves down there.
Being scared to do the exercises too hard actually is a good thing IMO.
Quite some people (me included) tried too hard because they didn’t know any better and quickly found out by injuries (some severe, some less severe).
In other words:
Listen to your body.
Do not think that something working for <insertnicknamehere> in wonderous way will work exactly the same way for you.
Rather find out what exercise in what intensity and repetitions works best for you and your body.
Generally:
Let common sense do the thinking.
If you are trying out a new exercise (or a known exercise with eg. more pressure or repetitions) check the indicators to your penile fitness:
Thread on penile fitness indicators
If it looks like you are doing something wrong you often are.. Simple as that :)
Oh and another thing you should probably check out:
Bib’s LOT Theory 101
Good luck with your gains,
Ys
She said you had a small dick huh? Well just remind her of what Tom Arnold said about his soon to be ex-wife, Roseanne, when she said very publicly that he had a little dick - "Hell, even a 747 looks small when you put it in the Grand Canyon". START: 2004-12-06 EBPL 6.70" BPEL, EG 5" CURRENT STATUS: Full Healing Break (Plasticized ligaments need time to heal -- Beware the rotating manual stretches ;) ) 2005-01-07 EBPL 7.68", EG 5" GOAL: EBPL 8.5" (ENBPL 7.9"), EG 6"