With proper form, push up can be a great exercise for the chest, arms and core. With poor form, they can cause shoulder and elbow issues in some people. Here's the correct form for push ups that will reduce the stress on the joints and reduce the risk of injury.
Your hand position should not be high and wide. They should be roughly in line with your ribs so that your elbows are close to your body. That is, if someone was standing above you and looking down while you did your push ups, your arms and body should create an arrow shape "->" not a ''P'' shape. This will reduce the stress on your shoulders.
Also avoid push ups where the hands are close together in front of the face or body, as this places undue stress on the elbows. The hands should be no closer than shoulder width apart.
Your hands should face forwards or be turned outwards slightly so that the index fingers are pointing to 11 and 1 o'clock. Don't rotate the hands inwards, as this also over-stresses the elbow.
Keep your core tight and your body in a straight line, as if you were doing the plank. Don't allow your hips to sag down, and don't create an "arch" shape by raising the hips. lf you can't keep this straight plank position, it means your core is weak and you need to work on this.
Maintain good form
Be wary of doing too many push ups .If you can't do them with proper form, keeping the body straight, the arms tucked in and the hands facing forwards, you've reached failure. Just stop, rest, and start a new set in a few minutes. Don't continue a set with poor form, or move the hands out to the "T" position just to knock out a few more reps. If you really want to continue, drop your knees to the ground and finish off the set from there.
Push ups are a highly versatile exercise that you can do no matter where you are, but just because you're not holding an iron plate doesn't mean there's no risk of injury. If you follow these guidelines, you'll go a long way toward keeping your shoulders and elbows healthy.