Imagine your truck is stuck in the ditch and you have 10 guys at your disposal who can pull it out. If you let just three guys pull, it is more likely one of them will get injured because they have to work considerably harder than if all 10 guys were pulling on the rope. This is how you should think of motor unit recruitment. There is no reason to do slow-grind reps that overload fewer motor units when you could recruit all the motor units and minimize muscle strain.
