 Now, this is the counterintuitive part. The weird thing is, in order for a muscle to relax, you actually have to cock your myosin heads. You can't relax if they're in this position because if they're in this position, they're actually attached. The only way to be in this position is to be attached to an actin molecule and to have already done the power stroke. So if you want to relax, you have to go back to a cocked position and the only way to do that is to put ATP into the mix. Now, I'm going to let you think about why. Number one, how weird is that? It requires energy to relax a skeletal muscle. To not contract your skeletal muscles requires ATP. You have to put in ATP to make it happen. And then use that information to analyze, like what is rigor mortis? What is rigor mortis? The rigor, the stiffness that happens when you die. I'm going to let you think about that because after that last little section, you deserve to think about it. And I'll talk to you later. What's up? Okay, seeing class. Bye-bye.