Which statement is NOT true about striated muscle fiber contraction?

I want to tell you 2 is the answer. There is time during a muscle contraction known as absolute refractory period. This occurs during the contractile phase and does not allow for another contraction even if the muscle receives another nerve impulse. This is very important in the heart because you want your heart to go through the entire cardiac cycle so you continue to pump blood. Short answer is cardiac muscle does not reach tetanus. The refractory period in skeletal muscle is much shorter so you are able to achieve wave summation and build to tetanus. This is why 1 is not the answer. 3 and 4 are true, so lets talk about 2. A single muscle fiber when told to contract will contract maximally. Force production is a product of motor unit recruitment. That means if we want to create more force we recruit more muscle fibers but each fiber contracts maximally when it receives the neural signal.