Why not do nothing is more like it. ;o). We often try to push through an injury only to take us 20 steps back. Trust me I learned to listen to my pain the hard way.
I cannot imagine a rib injury with a decline bench press other than if the bar hit his torso harder than he intended on the eccentric portion of the movement; he may have bounced the bar off his lower chest. There is no such contact with the dip, and it is considered by most to be a better movement for the chest anyway. But you're right. You shouldn't try to work through the pain if the movement causes it. Of course, the rib is not a joint, so that makes it a bit murkier. If he didn't bounce the bar at the bottom, then perhaps he just pulled a muscle and/or connective tissue.
Can´t post videos but one guy I train BJJ with is 53 y o and an absolute beast, handling folks half is age and with higher belts. We had the first competition in a while during covid (unofficial, behind closed doors) and he submitted promptly the 2 young dudes in his weight class who were most likely more experienced - he actually put one asleep in abt 30 seconds). No wonder people don´t want top roll with him when he shows up there for open mat... He was competing at high international level in TKD when young and has been practicing some kind of fightingt sport most of his life. About 100kgs for 190cms, not incredibly lean but still looking very athletic plus he´s very strong and explosive. Black dude. My new idol, hopefully I can also improve my way to the mid 50s and one day soon survive a round with him.
That's exactly what I am doing, resting. I don't know for sure how this happened. As Freddy eluded to it could have been the bar hitting my ribcage, but I don't recall anything other than a light touch. Certainly didn't hurt at the time. My guess is this happened during my sissy assisted pullups. I did feel a out of the ordinary stretch, did not hurt at the time though. Whatever the case it's better day by day, and the old me would probably be in the gym today. Not going to happen. I have already scratched out every day until Monday in my personal workout journal. So it is written, so it is done. I am sidelined until Monday for sure.
Upon further review of my recent workouts I think I have this injury nailed down. On my upper body day I have been finishing with some incline pushups using the Smith Machine. Start at about mid body level, do 10, lower bar, 10 more and repeat to lowest level. The lower it goes the more strain I feel in the upper ribcage area which is where this pain in located. I just added this about a week ago. Sherlock Holmes Obvious thinks this is it.
In which case you likely pulled a muscle or some connective tissue. Watch the placement of your hands in relation to your chest while doing the push ups. They should be below the plane of your shoulders at mid-chest/armpit level at the bottom of the movement. Keep your shoulders and shoulder blades down. And don't splay your elbows more than 45 degrees from your body throughout the movement. The push up seems like a simple exercise, but there are a number of moving parts.
Yes, my form sucked. This should help. The Perfect Push-Up To Build Muscle (AVOID THESE MISTAKES!) - YouTube