Answer:
According to the sliding filament theory, the myosin (thick) filaments of muscle fibers slide past the actin (thin) filaments during muscle contraction, while the two groups of filaments remain at relatively constant length.
Step-by-step explanation:
The sarcoplasmic reticulum stimulated to release calcium ions.
Calcium ions bind to troponin. ...
Cross bridges (on myosin) pull on actin (power stroke) ...
Cross bridge detaches from binding sites on actin.
Muscle fiber lengthens & relaxes.
Calcium ions actively pumped back into sarcoplasmic reticul