So myosin basically grabs the act and it pulls on it. So it walks on it and this creates our contraction of the muscle cell. Now, microfilament contain a negative end as well as a positive end. So let's suppose this is the negative end and this is our positive end and the actin essentially grows beginning from our positive end. And the negative end is attached to some type of structure within the cell. Now, as our actin grows from the positive end of our microfilament eventually it pushes against some type of structure within the cell, for example, the cell membrane.