Explain how muscle fibers generate graded forces eg twitch v

Explain how muscle fibers generate graded forces e.g., twitch versus tetanus.

Solution

A muscle consists of thousands of fibers with a huge number of nerve endings innervating into them.

Briefly put, a muscular twitch represents a short, jerky movement in response to a stimulus. As compared to the twitch, muscle tetanus is a longer response to multiple stimuli.

Muscle twitches represent the simplest types of muscular contraction in the body. A twitch is a single, brief development of force across a fiber, motor unit or entire muscle. In a twitch, the muscle fiber will contract only once. Post a twitch, the muscle fiber relaxes.However, the failure of the body to recognize individual twitches leads to a tetanic contraction, provided the output is constant. When the optimal rate of electrical stimulation of a muscle fiber is achieved, the muscle exerts the maximum tension, which leads to maximum tetanic tension. Emission of action potential at a faster rate also causes tetanic contraction.

Tetanic contraction is considered normal when performing activities that require a higher muscle tone ( like holding a box for a long duration).