Definition
The ability to keep producing force over many reps or a long time, such as sets of 20 or a loaded carry for distance.
It sits between maximal strength and aerobic endurance. Train it with sets of 12 to 25 at 40 to 60%, circuits, loaded carries, and short rests of 30 to 60 seconds.
It matters for field-sport athletes, tactical clients, and general clients who want to "do more", and it gives beginners a tolerance base before heavier work.
It is not a substitute for heavy training. A block of it after a strength block is the usual pairing.