I am amazed that it's been five years since I started this thread. I am still using a high intensity protocol. I lift twice a week, very occasionally a 3rd workout will sneak in. The workouts take under 20 minutes, and are never more than 9 total sets. Sets are taken to failure and sometimes a little beyond with a hold and/or forced rep and/or slow negative at the end. A set takes at least 45 seconds. Reps are slow and smooth; a rep should take at least 5 seconds to complete. Usually no more than 90 seconds of rest, but sometimes setting up the next exercise or waiting can take a bit. My progress is very slow, but I'll be 51 in less than a month. I don't expect YUGE GAINZ, not as a natty. I'm definitely not losing strength, even gaining a bit. I weighed 218 this morning. That's a little bit high. I have a goal of overhead pressing my bodyweight at 210. I can put up 190 right now without dying. Adding 20 to the bar while taking 8 off of me will be difficult.
This style of workout eliminates the no time excuse. Slowing down the reps reduces injuries, acute and chronic. The biggest drawback is that the short workouts are brutal. Today is going to take right at 15 minutes, and I will be wrecked. The good news is that I won't lift again until Sunday at the earliest. Barbells, dumbbells, machines, bodyweight, isometrics, I use them all. We are about to change gyms, so the mix is going to change a little. Vertical & horizontal push, vertical and horizontal pull, leg pressing movement, trunk extension, abs, neck, calves, and grip. Hit them all once or twice a week for a tough session and get on with life. No matter what you will obtain zero upside, burst, hip swivel, wrist-flickability, nor a room-brightening smile. At my age it's probably best that my hips stay boring.
Quick aside about age and bodyweight exercises. They suck. The first dip or chinup and you think "Geez, that's really heavy. Oh, crap, that's literally me." The rest of the set is as much a mental challenge as physical.