1) Bench Press
"How much you bench?" This is the ultimate feat for the meat head gym rats with stupid "I don't call 911" shirts in the gym. How much money you make, how many girls you slept with, all means nothing when you enter the gym, it's about this arbitrary number. Each Bro qualifies himself with this number, usually rounding up about 50 more lbs than what they really did, and it's from 7 years ago before they INJURED THEMSELVES.
These are the kinds of shirts these idiots wear to the gym
Why am I bringing this up?
Because these are the people that let their ego control them and end up ripping a pec because they try to impress the whole gym with how much weight they can push off their chest. But after the description you just read, it's best this person is injured and away from the you and the gym.
Now for you normal people who don't let their ego's rule them, let me address you're biggest issues.
You have terrible from.
Bench seems like an easy workout but most of you still do it wrong.
You flare your elbows out which puts most of the focus on your shoulders. Many people talk about how their shoulders are more sore than their chest and often injure their shoulders in the process.
What you need to do, even with pushups, is instead of flaring your elbows out, push them forward. This is how power lifters do it, and they have to. If they flared their elbows out when lifting that insane weight their shoulders would be done.
Let's not even get into how crazy power lifters bench form is
2) Lateral Raises
Now I could talk about how people swing the weight too much not getting the true effect of the workout, and abusing their low back in the process.
What I want to talk about is how bodybuilders will do lateral raises with their wrists turned pinkies up in order to hit the deltoids more in the exercise.
While they get a few percent more stress on their deltoids, they're stressing their Rotator Cuff way more. In case you didn't know, YOU DON'T WANT TO DO THAT.
Do lateral raises, ALWAYS WITH YOUR THUMBS UP.
On that note, you should always do rotator cuff warm up exercises. As your deltoids keep increasing in strength, your rotator cuffs need to strengthen as well. Otherwise there will be an imbalance which make you more open to injuring yourself.
Tall people beware. As good as your form may be, you're always prone to lower back injuries.
I know from experience.
If you're tall like Andre the Giant, no problem.
If you're tall like Dennis Rodman, then beware.
There's a reason why NBA players aren't allowed to do squats.
Some people are built for it, and some aren't as I've finally come to terms with.
Now, I could sit here and name a hundred things to make you better with form, but you'd be way better off just reading Starting Strength by Mark Rippetoe.
I will say the best thing you can do as a beginner is to start off with goblet squats.
Goblet squats will teach you how to properly hold the weight and do the technique.
Simply hold a kettle bell or dumbbell in front of your chest with your palms underneath, squat down until you feel your stretch reflex and then come back up.
That will put more stress on your glutes and hamstrings, instead of your knees.
Which is caused from leaning forward and stressing their knees.
Which brings up... Knees.
4) Leg Press
Some people damage their knees by keeping their legs too close together to stress the vastus lateralis portion of the quadricep. Don't be one of those people.
Some people put their feet too low to work the quads harder which also grinds on the knees. Don't be one of those people as well.
And whatever you, don't hyper-flex if you're somewhat double jointed. There's a YouTube video that will show you why, if you dare to watch it.
So many people hurt their low backs doing deadlifts. I was one of them.
Once again, read Starting Strength by Mark Rippetoe. Also, some people are meant for deadlifts and others not so. The hips are unique for every individual.
Deadlifts are a full body exercise, not a low back exercise. If you leave it up to your low back, you will put too much stress on it and injure yourself.
6) Single Leg Exercises
If you're overweight, do not do single leg exercises. You're not ready for this yet, and your body will tell you when you get injured.
7) Running, Plyometrics
Easy way to fix a lot these are dynamic stretching, rolling out, wearing proper shoes, and not having horrible form. That will solve most of your running problems, though you should definitely limit how much you run. There's a reason why running magazines are full of pain relief ads.
If you're going to jumping exercises, learn how to land correctly. When you land you shouldn't hear a loud sound.
You should land softly on the ball of your foot and roll into your heel, all while coming into a squat position. And just like running, and lifting heavy, don't over do it.
8) Skull Crushers
Tendinitis is often caused by things like tricep exercises. Skull crushers are a big one. Many people do the actual skull crusher where they bring the weight to their...skull, and they push it back up. This puts lots of stress on your elbows.
What you should do instead is bring the weight behind your head, reaching a stretch reflex, and actually flare your elbows out. This will bring your lats into the exercise and put less stress on your elbows,
9) Close Grip Bench Press
So many people put their wrists by going to close on close grip bench press and close grip pushups.
If your wrists are shoulder width, than that's close enough. If you want to go closer, you can but be careful and if you feel pain go WIDER.
Don't be this guy
Dips are a great workout, but if your feeling your sternum at all, DROP THE WORKOUT.
I love doing them, but my body is not meant for it. Same goes for you if you feel it.
Also don't go lower than parellel, you will over stress your shoulders and injure them.
11) Bent Over Row
Make sure you're not rounding your back, this is a common mistake I see every day.
Don't do those stupid Cross Fit kipping pullups and you should be okay. Only idiots hurt themselves doing pull ups. It's a simple exercise.
Problem is there's lots of idiots that think they won't jack up their shoulders doing kipping if they kip correctly. That's an oxymoron.
Calves are mostly genetic, but you can still build bigger ones. Thing is a lot people go heavy on calves, and then BOUNCE up and down putting too much stress on Achilles tendon.
Go slow and don't go too heavy, patience young one.
I could list a hundred rehab exercises for you, but I'm not a physical therapist or a rehab expert. I can tell you that the one thing more important than rehab is PREHAB. Preventing the injury is the most important thing. Listen to your body, lift correctly, take time off every now and then, and make sure to roll out and warm up. Simple rules like this should keep you in the gym and out of the surgery room.