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. This is when our calcium concentration increases. This is known as the contraction period, and this is known as our relaxation period. So now let's move on to our cardiac muscle contraction.