Question

multiple choice question which statement explains why a muscle fiber that is overly stretched generates less force than a muscle fiber at optimal length? there is too much overlap between thin and thick filaments so limited additional overlap can occur. stretching prevents calcium ion channels from fully opening, so some actin filaments cannot form cross - bridges. there is less overlap between thin and thick filaments so fewer myosin heads can bind to actin. need help? review these concept resources. rate your confidence to submit your answer. high medium low reading © 2025 mcgraw hill. all rights reserved.

Explanation:

Muscle contraction force depends on the interaction between thin (actin) and thick (myosin) filaments. When a muscle fiber is overly stretched, there is reduced overlap between these filaments. Fewer myosin - heads can bind to actin, resulting in less force generation. The first option is about excessive overlap (not the case in over - stretched fibers), and the second option about calcium ion channels is not the main reason for reduced force in over - stretched fibers.

Answer:

There is less overlap between thin and thick filaments so fewer myosin heads can bind to actin.