muscle twitch

http://lessons.harveyproject.org/development/muscle/twitch~1.htm

we don't need to kill frogs now in order to know and understand muscle twitch. sometime we wasted frog's life then learned nothing from it. that's tragic!
playing with muscle twitch in this website, we should have the picture of the myofilamints in our minds. it would also help if one will go back to the topic of skeletal muscle contraction which was posted here somtime ago.
the role of calcium ion is highlighted by this experiment.