Remember the up-downs they made you do during football practice ? This is a much kinder, gentler version of that. Face it: the older we get, the less enthusiasm we have for getting down on the floor and getting up again. So, why not kill two birds with one stone and undertake ground-training as a modest challenge and letting it suffice as a warmup as well ? What I did today: basically (1) did something like ab-walkouts ... but continued forward until I gently flopped down prone ... then walked my way back to standing position (2) from prone position twisted torso and pushed myself to standing with left arm ... then switched and did the same with my left arm and (3) rolled on back then sat up into cross-legged position. Just did these circuit-style for, oh, maybe three minutes total. I was huffing and puffing a bit and felt good to go! For me, since I'm not lifting heavy right now, this sort of warmup fully suffices for my needs. But even if you are lifting heavy, as long as you're doing specific warmups, this might suffice as a general warmup. And the really fun part is that you can just make stuff up!