The pushup is one of the most underrated exercises. It is a great corrective exercise, anterior core exercise and strength exercise. Yes big dudes, pushups are a great strength exercise (try throwing on a heavy weight vest and you will get the picture)!
The pushup is what Gray Cook and Lee Burton refer to as a Primitave Pattern. It is one of the first patterns we learn in the human growth development process. So, it is probably more important to learn a proper pushup before someone is squatting, lunging and deadlifting.
Also, you get some great serratus anterior activation because the scapulae are free to move. You don't get this in a bench press because we want a "packed" shoulder and minimal scap movement.
If you are not including pushups in your program.......start yesterday. If you are including pushups in your program, let's make sure you do them right.
Here are the three most common errors in the pushup:
1: Elbows flared (Yes, this hurt)
This can really wreak havoc on your shoulders over time. On a similar note, this is also a common mistake in bench pressing.
2: Sway back (Yes, this one hurt worse)
This is usually indicative of a weak core. Usually a pretty simple fix.
3: Head up
Driving the head up can tend to kick in the upper trap a bit and lead to some scapular elevation which can create instability in the shoulder complex.
And finally, a correct pushup!
Look to have "pillar" like stability through the body along with a slight elbow tuck. Also, focus on "clawing" the ground with your hands. This will create more shoulder and core stability.