Muscles don’t grow during the workout. They grow while you’re asleep. Rest is part of the rep.

The session is the signal and the recovery is where the change actually happens. Training only creates the demand, and the building takes place later, in sleep and on the days off, which means skipping rest does not add progress, it subtracts it. The same is true of learning and of hard mental work.

Put rest in the plan the way you put the work in, with the same seriousness. Protect sleep before you add another session. If you are training hard and getting nowhere, the missing piece is often on the other side of the effort.