: Rest for exactly 38 seconds, then perform a 49-second isometric hold (like a plank). 3. Scientific or Medical Reference

The phrase appears to be a highly specific reference, likely originating from a niche online video (such as a gaming walkthrough, a specific workout routine, or a long-form commentary) or a technical log.

"1138" is one of the most famous "hidden" numbers in cinema, used by George Lucas in almost every Star Wars and Indiana Jones film.