Identify A: Very brief delay between stimulus and contraction.

Identify B: Time when muscle generates external tension. The force generated can overcome the load and cause movement.

Identify C: Time when tension declines to baseline. SR reabsorbs Ca²⁺, myosin releases actin and tension decreases. Takes longer than contraction.

A muscle fiber remains unresponsive to stimulation unless the stimulus is of a certain strength, called the ____________ ______________.

It is the strongest stimulus that produces increased muscle contractile force.

The successive activation of the same and additional motor units with increasing strength of voluntary muscle contraction. It allows muscles to have slow, smooth sustained contractions so our movements are not jerky.

__________ _____________ occurs when a given set of cells is repeatedly simulated without complete relaxation.

Term that refers to how often stimulus is applied (or rate of delivery).

Term that refers to how often stimulus is applied (or rate of delivery).

The ______________ increases, more and more motor units are stimulated, and thus the strength of muscle contraction increases.

If repeated stimuli given a a slower rate, then muscle fiber contractions grow stronger as they summate but the relaxation between the contractions remains incomplete.

If repeated stimuli are applied at a fast rate, then no relaxation occurs between the stimuli, muscle reaches maximum tenstion and a sustained contraction phase is obtained.

This occurs when prolonged and strong stimulation of an exercising muscle reaches a stage when the muscle is no longer able to respond to the stimulation whith the same degree of contractile activity.

Identify the area in red: The period immediately following the firing of a nerve fiber when it cannot be stimulated no matter how great a stimulus is applied. It occurs first. It occurs due to the inactivation of sodium channels.

Identify the area in yellow: The period shortly after the firing of a nerve fiber when partial repolarization has occurred and a greater than normal stimulus can stimulate a second response. Occurs later.

Contraction in which the muscle is activated, but instead of being allowed to lengthen or shorten, it is held at a constant length. Example: carrying an object in front of you.

Contraction in which the tension remains the same, muscles shorten, used in movement. Example: a bicep curl,