Final answer:
A muscle stretched to 150% of its resting length produces less force due to the decreased overlap of actin and myosin filaments, which results in fewer cross-bridges, compromising the length-tension relationship crucial for muscle contraction.
Step-by-step explanation:
When a muscle is stretched to 150% of its resting length, it produces less force due to the decreased overlap of the actin and myosin filaments within each sarcomere. Muscle contraction depends on the formation of cross-bridges between these filaments, facilitated by the sliding filament mechanism. At the ideal sarcomere length, which is between 80% and 120% of the resting length, there is an optimal overlap that allows for the maximal number of cross-bridges to form. Stretching a muscle beyond this range decreases the overlap, leading to fewer cross-bridges and, hence, reduced muscle tension and force production.
Furthermore, when a muscle is excessively stretched, as would be the case at 150% of its resting length, the length-tension relationship is compromised. This relationship describes the strength of a muscle contraction as being directly related to the muscle's length at the time of contraction. Beyond the optimal length-tension range, muscle fibers produce less tension, which translates to less force, because the potential for cross-bridge interaction is significantly reduced.