It is a general term for all of these things: being pleased with the way you look naked, feeling energetic, and having well-developed strength/musculature, cardiovascular endurance, and athleticism (agility+speed+power).
I pretty much follow something like the Maggie's program of a combination of weight-lifting, calisthenics, and endurance cardio. About 5 hours weekly but I also play sports one night/week and on weekends. I watch my nutrition carefully because many middle-aged women have a tendency to get sloppy regardless of their exercise program. (No rational amount of exertion can produce fat loss, unfortunately, but physical exertion does reduce subjective hunger and "false hunger" - the hunger that overweight people experience.)
Regarding muscle maintenance and strength-building in middle age (40+), I want to highlight a paragraph from yesterday's post:
Research has demonstrated that low load high intensity lifting at 30% of the one repetition max (1RM) to failure can elicit similar rates of muscle protein synthesis as traditional, high load low intensity lifting at 90% of 1RM. Data suggests that low and high load lifting performed to failure yield equivalent hypertrophy over time. So exercise volume (repetitions x sets x load) can achieve maximal muscle fiber activation, including the important larger type II fibers. This is also much less likely to cause injury, an important consideration at any age.
Note that it says "to failure." That is the key, and that is the tricky part because the mental "I give up" almost always precedes the muscles giving up. Fighting that mental part is the discipline of exertion, and why trainers know they can almost always say "C'mon, give me one or two more." Women have no need to fear developing the hard or bulging muscles of their fit and athletic menfolk. That can't happen naturally with females.
To hedge your bets on the current consensus, I suggest going heavy with the weights on power lifts occasionally. You might even see your 1RM increase if you dare to check it (with a spotter) every few months.
