And once the concentration increases to a very high value, basically when this time elapses, then only then do we have our contraction actually taking place. So, in skeletal muscle, the action potential leads to the opening of the calcium channels on the sarcoplasm reticulum. And as the calcium ions begin to flow into our sinoplasm, that increases the concentration. And only when the concentration is high enough, when this time actually passed, does the muscle contraction actually take place, because only then do we have enough calcium to actually bind to the actin of our thin filament and initiate that contraction between the thin filament and the thick filament inside the sarconer of our muscle cell. So this is our description of the skeletal muscle contraction. So this is known as the latent period.