I just watched a video on youTube, and the guy said that proper form is a myth. I know we "the Hermanation"belive in proper form but why is there so many people that says it doesn't matter all that matters is how you feel?

WHAT!!! 

They don't care about injury, only gains.

That's crazy. But I'm gonna go with it's straight up ego...or potentially bad coaching, depending on the situation. But form first! When you can hit a big PR with great form, then you've earned your right to have an ego! 

I gave my take on it in this forum post:
http://scotthermanfitness.com/forums.php?pageAction=POSTS&subForumID=32&threadID=184

Yeah some people just don't care about risking injury and it's all about their ego! I believe form is the most important part of an exercise because if you injure yourself, bye bye gym, and thats the worst consequence of all. I highly agree with csariraksa, once you make an awesome PR with proper form, then you can have an ego!

I love it, thanx people. My opinion is that proper form makes the exersise much harder and only in proper form the exersize builds the muscle as it is intended to.

Well yes but if you saw my forum post you would also know that it is ok to go a little of perfect form

All I have to add on this is this: form isn't EVERYTHING, but it's still important to avoid risk for injury. My point is, if you lift 90% of your 1RM, you're GOING to sacrifice form to get that weight up/down. For strength-gainers, this is the whole point...to push/pull a very hard amount of weight so they can do it more. Am I saying throw your whole body to and fro until your body is half-twisting while doing a single barbell curl? No! I'm just saying you ARE going to use some of your back and legs when you curl 130 pounds, and your 1RM is 140, and it's going to happen.

NOW if you were curling 70% your 1RM or lower, I would say be more strict on the form. The lower the weight, the stricter you should be on maintaining the form. For my curls when I drop down to 30 pounds on the BB, I lock my shoulders and arms just right so my biceps are the ONLY muscles being activated in the lift. Since I don't have a preacher curl machine, I have to improvise.

Overall, I would say if you're going for strength gains and using very high weights, you're not gonna get the form 100%, so don't get caught up about that like I used to. It ALL depends on your goal how strict with form you should be, and realize that these myths need to be laid to rest. Like I said, 100-75% 1RM = form is going to be sacrificed, but try to keep as much of it as possible. Anything 70% and below, start to focus on maintaining form better the lower in weights you go. If you arch your back just a tiny bit in your curls, don't sweat it too much, just try to keep it as straight as you can and when you get stronger it should correct itself.

Kevit07 is spot on.  95% of your workout should be with proper form in weight.  5% of the time it is OK to sacrfice some form to get some extra reps or to push beyond your normal limit.  I would never, however, do cheat reps on squats, deadlifts, shoulder presses, chest presses, or bent over rows because the chance of injury is immense.  I sometimes use them for barbell curls or pull ups or side lateral raises - exercises where some momentum will help push over your limits but don't involve movements that can hurt you.  In general always choose proper from over cheat reps but if done safely and infrequently, cheat reps can help push a muscle over the edge.

John

I agree with the rest of these guys as to why people think that it's a myth. Think about it. When you are training with improper form you are actually taking tension off the muscle being trained and are much more vulnerable to injury which can put you out of training for a while. You would be best off lifting an amount of weight that you can control with proper form and make small slow improvements then to be throwing weight around using multiple muscle groups and getting injured. While you are recovering from an unecessary injury that should've never happened in the fist place you will lose all the gains you have made. I am definitely not a form critique, but it does make me cringe to see people at the gym use improper form each week and never get anywhere but injured. Its better to be safe than sorry so always maintain proper form. You will make more steady gains and wont have any aches and pains later in life. Now if you are going to cheat slightly the last couple reps of a tough set that is fine as long as you are working a slow negative, but just for the last 2 reps. If you are having to cheat with more than 2 reps then lighten the weight.

Yeah man never sacrifice form for more weight! With improper form injuries can occur and then you can't workout at all !!