Final answer:
The tension developed during a twitch within a single muscle fiber depends on the number of cross-bridges formed between actin and myosin.
Step-by-step explanation:
The tension developed during a twitch within a single muscle fiber depends on the number of cross-bridges formed between actin and myosin. Cross-bridges can only form where thick and thin filaments overlap. If more cross-bridges are formed, more myosin will pull on actin, resulting in greater tension.