When I started doing resistance training, 25 years ago, I had the convenience of a wonderful gym with a big weight room, lots of equipment, but few patrons in the evening. I also had a copy of The Cyclist's Training Bible. Friel said that if you are starting out, a good idea would be to do circuit training with about 9 different lifts and starting with 3 sets of 20-30 reps. So that's what I did, because I could, and I did it twice a week, Tuesday and Thursday. Being a fan of conditioning, I chose the 30 rep option. Circuit training means you do one set at each station and then go around again for the second and third sets. I wore a heart rate monitor and I'd let my HR drop some, but not too much between stations. I stayed aerobic.

I chose to do all three sets using the same weight for the 3 sets at each station. Just to be clear, I used a different weight at each station. I chose a weight which made it impossible to do all 30 reps for the last set, 28 reps being just perfect. I'd increase the weight for that station if I hit 30 on that last set. I increased the weights a lot over that first winter. By the next year, I would work in with the big guys on the leg sled if it was busy, just doing the standard 10 or so reps. So yeah, it worked and I got strong and also got way faster on the 60-80 mile weekly hilly group rides. I could do a fast 400k with no training ride over 60 miles. And this was in my 50s and early 60s. So yeah, it worked.

However, once I'd done this year 'round for 3 years, the time it took became an issue and I changed over to the standard method of 3 sets of 10-12 reps at each station, which did well for strength maintenance.
My circuit was:
1-Hip extension (barbell squat)
2-Seated row
3-Back extension
4-Hip extension (leg sled)
5-Bench press
6-Heel raise (one-legged, no weight, full range of motion)
7-Stiff-legged dead lift
9-Lat pull

When I became interested in serious road riding it was the year that Bicycling sponsored a team of four over-50 y.o. riders on RAAM. I can't remember which rider, but one of them could sled 450 lbs. 50 reps. Yeah!