Pain -- is it good or is it bad? When it comes to the gym, it's both and neither.
There are two kinds of pain people feel during and after intense resistance training:
1. Muscle fatigue and micro-tears of the muscles -- this is 'good pain.' This is what causes hypertrophy -- bigger muscles.
2. Connective tissue pain -- this is 'bad pain.' This is the feel of tendons and other connective tissue being pulled to the point of injury. And those of us who have experienced this pain know like love it is not necessarily forever, but it can feel like it.
I watch people workout and can almost tell you to the person who is going to get hurt -- as in 'bad hurt' -- as in the kind of hurt that puts them out of commission for a while or forever.
Here are the three categories of people who are hurt or about to get that way:
1. The Testosterone boys. These are the young guys who come in together, all worked up, do no stretching, warmup exercises, and try to handle weight way above their physical capacity in order to impress their buddies. Instead they leave hurt and I rarely see them again.
2. Look What I Can Lift guys. Mostly guys, but some girls, too, and here's the problem -- they are more interested in how much weight they can handle rather than their look and overall physical condition. They are powerlifters or wanna-be powerlifters. They almost always go down to injury.
3. To Hell With The Form folks. These people never learned to lift right -- don't know what range of motion means, what the squeeze is, how many sets or reps are ideal, and mostly how to perform a repetition with heavy weight in a way that minimizes risk of injury. They need a trainer before they hurt themselves. Unfortunately, most of them hurt themselves and then decide they need a trainer.
There is a fine line between not putting 100% into your workouts and getting poor results and putting too much into the workout and ending up injured.
After spending a lot of time in the gym, you get better. You know the difference between 'good pain' and 'bad pain.' Better than having to learn the difference by trial and error is to avoid being in one of the three categories I discussed above.
Train hard; diet harder!