A very good workout with M. this morning.
(I saw reason and did not swim first - I've got a hard run scheduled for later - my fall-semester exercise schedule is still under construction...)
He was just finishing up his own workout (45 minutes, shoulders) when I got there, and I persuaded him to join me for the first couple rounds of the core stuff we usually open with. It was very fun, he is absurdly fit and athletic but he slightly skimps on that stuff in his own workouts so it was a good chance for me to give him a taste of his own medicine!
(This is a good routine that I really like, in fact I have no excuse for not getting back into the gym for a second or third weekly session on my own and doing just this half-hour of core stuff - I have a slight psychological block on doing a real strength workout on my own, I find it a bit boring and lose patience, but I like this core stuff a lot. 60 seconds front plank, 30-45 seconds each side of side plank, 15 x cobra with three-pound weights, 15-25 pushups, 15 x "quadruped" [kneel on all fours, raise 5- or 8-pound weight in one arm while extending opposite-side leg straight to the back], then something like 15 V-raises and 15 toe-touches, or 15 crunches with a weighted bar and then 15 without. Repeat three times.)
Just upper body and core - I am being super-cautious with everything to do with legs and hamstrings!