If you feel the stretch during the guilotine in the shoulder joint, biceps or frontal deltoid at all you are going past the glenohumeral joint range of motion and actually pushing it up and out of the the socket a little. If you have a funny feeling that one pec is a step behind the other (i.e. One feels stretched first during the movement and then the other then catches up) even though you lower the bar evenly you most likely either have a winged shoulder, a rolling shoulder, or both. Most people have a forward tilt on the dominant arm and a rolling shoulder on the non dominant arm since you body looks for the most efficient way to lift the weight and ends up compensating.
If you have this problem you need to stretch out the muscles holding your shoulder in its unnatural posture. You’ll most likely need to see a chiropractor or professional as the internet is a terrible source for correct exercises to do this. You’ll thank me and your shoulders after you do. If you don’t see someone stop benching or else you going to run into problems down the road as you continually run the shoulder ragged by pushing it past its range of motion
Once corrected do the guillotine press while pinning your scapula down and back (pushing your chest up and out) and focus on contracting them the entire rep. Also, supinate your wrists slightly inward on your grip while keeping the elbows and forersm lined up beneath the bar the entire time[/quote]
excellent ost bro great knowledge with some anatomy thrown in love it