You can't wear goggles when someone is punching you in the face--good chance of them breaking or getting smashed into your eye.
Plexiglass can very strong. And goggles could be very big even covering most of the face. The problem is I think it either offers too much protection making the fight unfair, or it could break a bone on the face due to concentrating the pressure of punch where the goggles are resting on the face. We both agree it doesn't work, which is why I have never thought seriously about a comeback into sports at an old age as a boxer. I seem to have a talent for rapid fire combinations. My quickness is similar Manny Pacquaio but alas it is not meant to be for me to actually compete in the sport. Too late. Probably for the best.
MMA is my choice--it's mixed so it's Brazilian jujitsu, kick boxing and wrestling, plus a few other things like sambo, judo, and various forms of karate.
I am familiar with the techniques used inside the MMA ring. Boxing doesn't seem to be effective because the wrestlers just go for the legs and take you to the ground.
You are challenging me to a technically skilled sport where I have absolutely no training, so it wouldn't even be a contest. You might as well just ask me if I can give you a knife to stab me with. I am basically asking to have my arm or leg broken or dislocated. That would be insane. Of course I would simply have to fight dirty and break the rules in order to compete, so in a real life situation I would poke your eyes out, ram your nose up into your brain, etc, but then this wouldn't be friendly sport any more but rather survival.
So of course I will decline.
I was looking for a friendly afternoon on the field where I could teach you to have some respect for a 50 year old man. Bruise each other up a bit, but unlikely any serious injuries (although broken bones aren't totally impossible, the likelihood is much less than dislocation of an elbow in grappling). But since you imply you have no experience at grass field sports, then I guess we can't do it.
The decathlon would require far too much training on my part. Unless I was set on getting back into that shape any way, it would be a distraction. Football shape is something I would like to reattain any way, because it is a cross-training type of conditioning with explosiveness.
I suppose our only comparable sport would be boxing since I have no training and you have some capability to do that in an MMA. Or we could allow kicking also such as the Thai version of boxing. But again I would risk my eye and thus the rest of my productive life. Hardly seems worth it. If I could find some sort of head gear with a clear plexiglass over eye, and you want to fight for points (can't really hurt each other with headgear on), then that would be an interesting competition.