I’ve done basic circuit training fairly consistently for over 20 years. Examples include lat rows, dead lifts, curls, overhead raises and shrugs, all with dumbbells. Also push-ups, planks, side plank with leg lifts, and then the type of crunch with legs raised a bit off the floor and extended and lifting the head and torso just off the floor, both middle and each side. Not to add mass, just to maintain tone and fitness. Now that I mainly run, I want to keep my weight just where it is.
Otto