Ahh the Bench Press!
A Wide grip forces the elbows to flare out, putting the bar right over the chest. With the arms perpendicular to the torso this will increase the demand on the Pec’s and reduce the demand of the triceps. Some may argue however that this can cause shoulder pain, making the risk not worth the gains.
The more narrow the grip leads to a more elbow tuck leads to an Increase demand placed on the triceps. The moment arm is increased at the elbow joint, which makes this exercise a tricep dominant exercise. You won’t be using your pec’s as effectively in this position. It is important to have proper pronation range of motion with the forearm for proper execution of the narrow grip. The elbow joint is not meant to go into abduction or adduction motion, if the forearm can’t pronate enough the medial elbow will be stressed.
I am not going to say which one is better or worse than the other. They both have their pros and cons.
Often bodybuilding will go wide grip in order to isolate their chest more efficiently. On the other end, power lifters will often maintain a slight elbow tuck in order to maximize power with assistance of triceps and minimize risk of shoulder injury with a heavy load.
How do you #benchpress ?