More tension is developed during twitch summation than during a single twitch because the duration of elevated cytosolic Ca²⁺ concentration increases during summation, thus increasing the availability of cross-bridge binding sites.

Question

Quizplus · Accepted Answer

During twitch summation, multiple action potentials lead to an increased release of Ca²⁺ from the sarcoplasmic reticulum, resulting in a longer duration of elevated cytosolic Ca²⁺ concentration. This allows for more cross-bridge cycling, leading to greater tension development compared to a single twitch.

More Tension Is Developed During Twitch Summation Than During a Single