The volume is real, not a token. The week lands at roughly 11.2 weighted sets for quads, 11 for the upper back, 10.7 for glutes, 8.7 for hamstrings and 8 for chest, with delts and traps both at 7.4. That is squarely inside the productive band, from four sessions and only two lifting days. Two honest accounting notes: the interval day is counted as a moderate 3-set-equivalent because its cost is mostly cardiovascular, and the Saturday spin as a light 2, which is genuinely what an easy hour costs you.
Zero recovery flags, with margin rather than by a hair. Every muscle loaded on Monday is loaded again on Thursday and not before: 72 hours, then 96 back around to Monday. Nothing is inside its window, and most things clear it by a full day. The two aerobic sessions are deliberately dosed to stay under the threshold that would count as a hit on legs, which is why the Saturday spin is easy and stays easy. That is the two-day rule made visible: never the same muscle hard on consecutive days, and for the big 72-hour muscles, never inside three.
What actually changes after 40. Three things, and strength potential is not among them. Recovery rate slows, so the same session takes longer to absorb. Tendon and connective tissue adapt more slowly than muscle does, and that gap widens with age, which is why the classic over-40 injury is a tendon complaining about a jump in volume the muscle handled fine. And the cost of an injury rises sharply: the same tweak that cost you two weeks at 25 costs you two months at 45, and two months of not training is the single most expensive thing that can happen to a training year. What does not change is the ability to get stronger. Masters records keep falling, and untrained people starting in their sixties still add meaningful strength and muscle.
Intensity stays. Junk volume goes. The instinct at 40 is to train lighter and more often, which is exactly backwards. Heavy loading is the specific stimulus that maintains type II muscle fibres and bone density, both of which are genuinely on the clock with age, and you cannot replace it with more sets of easy work. What you can afford to lose is the third and fourth accessory movement, the extra arm day, the sets performed because they were on the sheet. This program keeps hard sets close to failure and simply runs fewer of them.
The aerobic half is not optional. VO2max declines by roughly 10 percent per decade in untrained adults, and it is among the strongest single fitness markers associated with all-cause mortality in the observational literature. That is an association rather than a promise, but it is a large and consistent one, and VO2max is one of the few things on that list you can move directly. Once a week of 4 × 4 intervals is enough to hold and usually improve it; our guide to raising VO2max covers how to pace the protocol properly.