Final answer:
When a muscle is loaded with more weight, it takes longer for the muscle to begin to shorten and the muscle shortens less.
Step-by-step explanation:
When a muscle is loaded with more weight, it takes longer for the muscle to begin to shorten and the muscle shortens less. This is because the force needed to move a heavier load is greater, which requires more muscle fibers to contract. The more fibers that contract, the stronger the force generated by the muscle. When the load is heavier, it takes more time for all the sarcomeres in the muscle fibers to shorten, resulting in a longer time for the muscle to begin to shorten and a smaller amount of shortening overall.