During muscle twitches sarcomeres shorten maximally How can

During muscle twitches sarcomeres shorten maximally. How can you explain the difference in the amount of movement of the finger when just the frequency of stimulation changed?

Solution

During muscle twitches sarcomeres shorten maximally. The difference in the amount of movement of the finger when just the frequency of stimulation changed due to change in the amount of motor unit recruitment, & if the tension in the muscle increases from 40 to 50 msec is leading to high twitch contraction whereas it the tension is lesser then the lower twitch contraction of finger muscle. The process of simultaneous activation of muscle fibers by active force generated through threshold voltage finally this active force attains a plateau stage (can be detected trhough myogram) this is referred as maximum voltage irrespective of muscle fiber activation associated with spike. The finger muscle fibres are mainly white-fast-twitch muscle fibers & these muscle fibers referred as fast glycolytic muscle fibers and they possess \"higher ability to produce stronger contractions if the frequency of stimulation changed\" when compared to the normal type II skeletal muscle fibers. This is because these finger-muscle fibers highly adapted to generate quick responses and these muscles are rich in muscle phosphogen to produce efficient stronger contractions when subjected to stronger cholinergic stimulus from autonomic ganglia. They possess higher surface expression of muscarinic and nicotinic receptors to act for the” stimulus intensity produced by active force” followed by generation divalent calcium from sarcoplasmic reticulum rapidly to generate contraction (8ms per one twitch).