The greater the number of _________  involved in a motor unit, the ________ the degree of fine muscle control.

The motor unit types (S, FR, and FF) that were initially identified in the cat medial gastrocnemius muscle were based on all of the following EXCEPT?   a.) The mitochondrial density of the muscle fibers innervated by a single motor neuron b.) Contraction time  c.) The amount of force a motor unit would produce d.) How quickly a motor unit would fatigue during a fatigue test

According to the size principle, which type of muscle fibers are recruited last during a muscle contraction? Group of answer choices:   1.) Type I 2.) type IIB 3.) Type IIA