Question

what percentage of the resting length of a sarcomere is ideal for producing maximal tension because it maximizes the overlap of actin-binding sites and myosin heads?

a.) 160%-220%
b.) 80%-120%
c.) 40%-80%
d.) 120%-160%

Explanation:

Identify the physiological principle of the length-tension relationship

The length-tension relationship of a muscle fiber dictates that maximal active tension is produced when there is optimal overlap between the thin (actin) and thick (myosin) filaments.

Determine the optimal resting length percentage

Physiologically, the optimal sarcomere length for producing maximal tension is close to its normal resting length, which is defined as 100%. The range that maintains near-maximal overlap and tension generation is approximately 80% to 120% of this resting length.

Evaluate the given multiple-choice options

• a.) 160%–220%: Sarcomere is overstretched, reducing filament overlap and tension.
• b.) 80%–120%: Represents the optimal range for maximal cross-bridge formation and tension.
• c.) 40%–80%: Sarcomere is overly compressed, causing filament interference and reducing tension.
• d.) 120%–160%: Sarcomere is moderately overstretched, decreasing tension.

Answer:

• a.) 160%–220%
• b.) 80%–120% (Correct answer)
• c.) 40%–80%
• d.) 120%–160%