MEDICAL PHYSIOLOGY

Detailed explanation-1: -Increasing the number of active motor units (ie, spatial recruitment) Increasing the firing rate (firing frequency) at which individual motor units fire to optimize the summated tension generated (ie, temporal recruitment)

Detailed explanation-2: -Motor unit recruitment is a measure of how many motor neurons are activated in a particular muscle, and therefore is a measure of how many muscle fibers of that muscle are activated. The higher the recruitment the stronger the muscle contraction will be.

Detailed explanation-3: -Motor unit recruitment is the process by which different motor units are activated to produce a given level and type of muscle contraction. At minimal levels of muscle contraction (innervation), muscle force is graded by changes in firing rate (rate coding) of individual motoneurons (MNs).

Detailed explanation-4: -Activation of motor units in a random order produces a roughly linear force increase with progressive recruitment, whereas recruitment of motor units in order of increasing force produces an approximately exponential force increase as the number of active motor units increases.

Detailed explanation-5: -Answer and Explanation: The answer is B. Motor unit recruitment. Motor unit recruitment is the successive activation of the same and additional motor units with increasing strength of voluntary muscle contraction.