In iOS 14.4, apparently you’re free to.
These could be power walks, regular walks, or runs.
Whats the Point?

Apple
We could speculate all day about the format these workouts will take.
Will they use music?
Offer guided walking instructions?
But we can talk about the efficacy of guided walking workouts.
You definitely dont need new workouts each week.
The one big advantage of walking is that almost anyone can do it.
You dont need special gear, a gym, or a running track.
it’s possible for you to just go out and walk.
How might this fit into the Time to Walk feature?
It could be as simple as a series of instructions to speed up and slow down while you walk.
Free, plentiful, and automatically delivered, podcasts are just about the best walking companion around.
Apart from a dog.