From Chapter 13 of Atomic Habits:
"A habit must be established before it can be improved. If you can’t learn the basic skill of showing up, then you have little hope of mastering the finer details. Master the art of showing up."
@JamesClear Woody Allen correctly stated that " ‘Showing up is 80 percent of life.’ Sometimes it’s easier to hide home in bed. I’ve done both."
In other words, the reason you don't feel like working out is because you don't work out.
Objects in motion tend to stay in motion.