sliding filament hypothesis

noun

slid·​ing filament hypothesis ˈslīd-iŋ- 

: a theory in physiology holding that muscle contraction occurs when the actin filaments next to the Z line at each end of a sarcomere are drawn toward each other between the thicker myosin filaments more centrally located in the sarcomere by the projecting globular heads of myosin molecules that form temporary attachments to the actin filaments and become detached when the actin filaments move in the opposite directions toward the ends of the sarcomere

called also sliding filament theory

see crossbridge