Range of motion makes a huge difference. Most of these people claiming huge poundages on dumbbell benches and military presses are probably doing partial reps. I see it all the time.
Maybe,But you have to remember this is the INTERNET and 99% of people don't tell the truth here. These people claiming they can rep with 120lb dumbells probaly can hardly rep with 80lb dumbells.
In reality most PRO's can't even rep with 160lb dumbells and I see people under 180lbs claiming they can alot on the internet.
Hell...The pictures you see of Pro's holding these 180lb dumbells aren't even real..They don't lift with those weights. They are only holding them for photography purposes and someone like cutler could probably hardly do 2 or 3 reps with them.
Most of the Pro's in reality can't benchpress over 500lbs...Someone Repping with 180's would be able to do 500 easly considering barbells are alot easier than dumbells. Benching 300 on a bar is alot easier than benching 2 150lb dumbells.
Funny thing is...A great deal of people on the Internet claim to use these massive weights like 120 or 150lb barbells..But I've worked in a gym for years and this isn't one of those fitness clubs,It's a gym where 60% of the people are over 200 and built. I see people using barbells over 120lbs maybe a few times a month and even then it's just for show.