# Conservation of angular momentum: Toes to Bar (TTB)

In physics, angular momentum (in simple terms) is the product of mass of an object (m), the distance of the object from the center of rotation (r) and the tangential velocity of the object (v):

L = m * r * v

Angular momentum is conserved unless there is external torque (force). In other words, m, r or v can change, but L will stay the same. Therefore when you decrease the radius of a rotating object, the velocity must increase to conserve angular momentum. If this doesn’t make sense, don’t worry, just trust me. This is why when a gymnast tucks their legs, they rotate faster and when a skater pulls their arms in, they spin faster.

So what does this have to do with CrossFit? Everything. Moving your body in space requires that you operate within the laws of physics; thus it is beneficial to know what the rules are. Let’s take toes-to-bar (TTB) for instance. When we “kip” (or arch and hollow in a pendular fashion) to do a TTB, we all know from experience that bending our knee joint makes our legs seem to go up easier. That is because you are decreasing the radius of our legs (r). Since angular momentum (L) is conserved and the mass of our legs (m) is constant, the velocity of our legs increases. So bent legs is better right? Only if you do it the right way.