Here's a story. I was at a 50s event a couple of years ago. My friend Donna asked me to dance with a friend of hers, so I tried a few basic swing moves -- just some simple turns. After a couple of turns, this gal said, "Boy, you have a lot of energy."
Admittedly, I do; however, the moves I was doing were extremely basic and not very demanding. The problem wasn't that I had plenty of energy; rather, the problem was that she had virtually none. She moved in a plodding way, with no bounce to her step and scarcely moving her feet.
That's the way a lot of people are nowadays, though. Americans have become very lazy. I'm reminded of the time I was at a social outing on a nearby island. Our travelling group had planned a bike ride, but these three ladies decided to rent a golf cart instead. I overheard them say, "Yeah, we're being smart! Their butts are going to be sore, but we're going to be taking it easy."
The thing is, it doesn't take much energy to ride a bicycle. If you're in halfway good shape, your posterior is not likely to ache -- not unless you're pedalling uphill or at high speed for half an hour or so. In case you were wondering, two of these women were very much overweight, and I think the third one looked a bit sedentary as well.