And that in turn increases the thickness, increases our diameter of each one of these myofibrils. And over time, because our thickness of each of these myofibrils is increased the entire thickness and diameter of the muscle cell will increase as well. And because it's the actin and the myosin that basically move along each other to produce our force, it's these that create the force in the first place. A thicker muscle cell means we're essentially producing a larger force. So when we exercise often we increase the thickness of the individual myofibus down inside each muscle cell by increasing the number of actin and myosin in those myofibus. This in turn increases our thickness, our diameter of that muscle cell.