Question

During a sustained submaximal whole muscle contraction (like muscle activation that keeps your head upright throughout the day), what is happening in your neck muscles?group of answer choices

O some motor units are activated to incomplete tetanus while others are resting
O all motor units are activated to twitch in unison (synchronously)
O some motor units are activated to complete tetanus while others are resting

Answer 1

During sustained muscle contraction for postural maintenance, some motor units in the neck muscles enter incomplete tetanus with alternating rest periods, which is a strategy of motor unit recruitment for endurance and preventing fatigue. The answer is option A.

Step-by-step explanation:

During a sustained submaximal whole muscle contraction, such as the muscle activation that keeps your head upright throughout the day, the neck muscles experience a phenomenon where some motor units are activated to incomplete tetanus while others are resting. This process allows for muscle endurance and prevents fatigue, enabling prolonged muscle contraction.

The active motor units undergo a series of repeated stimuli, resulting in summed muscle contractions with quick cycles of contraction and brief relaxation phases, which is characteristic of incomplete tetanus. Meanwhile, the alternating rest periods prevent complete fatigue by allowing some motor units to recover while others are active, which is a strategy of motor unit recruitment used by the nervous system for efficient skeletal muscle function.