Many beginning exercisers are concerned about using proper form when working out. We have all heard about the evils of using bad form. In general, form is important BUT - don't sacrifice your workout to the "Form Police."
Too many Personal Trainers will tell you that the form must be perfect. They'll say if you can't do an exercise with perfect form, you must stop and/or lighten up the weight. Often you end up with a "workout" that has had the life sanitized right out of it! You keep lightening everything up and stopping as soon as your form falters - and you leave the "workout" without ever breaking a sweat or breathing hard. That's not a workout. That's a waste of time.
Another problem is Personal Trainers that confuse themselves with Physical Therapists. As soon as they see something wrong with your form, they tell you some BS story like "Your trying to compensate with your teres minor, because your infraspinatus is weak." So they give you a bunch of silly "exercises" for you infraspinatus ("exercises" that are so easy most people could do them in their sleep!). I think those trainers are usually just trying to make things sound complex, to make themselves sound smarter than you, and to make you dependent on them. If you ask me, that's like a fireman telling you "Sure, we'll put out the fire, but first, let's dust the shelves, make the bed, and wash the dishes." HELLO - the house is on FIRE - let's set some priorities here! If someone comes to me with an extra 100 pounds of BUTT, I'm going to help them get rid of the butt before I worry about their infraspinatus!
There are times when form is critical. It takes an experienced Personal Trainer to know when form must be very strict, and when it's OK to "cheat." I always say "Cheat to make it harder, not easier." By that I mean when you can no longer keep good form you have two choices: stop - or cheat. Stopping is very easy, and it does your muscles no good. I say keep going, even if you have to cheat. The extra reps you get at the end do you more good than the easy reps at the beginning of the set.
Having said all of this, you must be careful to cheat in a SAFE way. There are exercises where if your form is bad, you risk an injury. So don't cheat unless you know exactly what you are doing. For example, when you are failing with an overhead press, DON'T cheat by leaning back. This puts your lower back at risk for a serious injury. A safe way to cheat would be to bend the knees slightly and let your legs give you a little push, a little momentum on the way up - while keeping the back very straight.
It's hard for most people to know how and when it's OK to cheat. One rule of thumb is that you should never jerk the weights around. The best thing to do is to hire a professional. A good Personal Trainer will always tell you when your form must be perfect, and when it's safe to let it slide a little bit. Just make sure your trainer is putting out the fire before dusting the shelves....
Chicago Personal Training