When a skeletal muscle fiber contracts during an isotonic concentric contraction, the distance between the Z bands of a sarcomere increases. True / False.

False

Explanation:

The Z-line is a structure formed between adjacent sarcomeres and is found at each end of the sarcomere in striated muscle and defines the lateral boundaries of the sarcomere, its function is to give anchorage to titin and to the outer ends of the thin filaments. Due to this anchoring function, the Z-lines are responsible for force of transmission and during contraction, as the sarcomere shortens, the distance between Z lines lessens

Answer: False

Explanation: as the muscles shortens due to contraction, the actin filaments from opposite ends of the sarcomere approach each other. So the two Z bands come closer with reduction in length of the sarcomere