I guess you fellas and gals are alot younger than me or played less contact sports. I'm 43 and let me tell you....pushups crush theshoulders now. So does Bench. Be careful with it. I can only do about 25 now and won't even try it any more. clicking and popping galore when i do them.

A gym is a great idea. I d.o go there and still have most of my strength...just some scars from the battles over the years.

Pushups are a godd up[per bod exercise. I'd mix it wiht something like pullups for the back. An abroller is good if you don't like pushups. This is the best time to work out...no doubt.

body weight training are super ! get a pull up bar,do push ups (no idea why you need to strive to 100 it sounds kinda silly to me),its always nice that you can do this things almost anywhere at any time (even in the bus stop if your not shy haha).
also i recommend lounges,tricep dips (can use a chair,as you probebly know) and body weight only proper squats (the whole foot is on the floor as you go down).