Essentials: Improve Flexibility with Research-Supported Stretching Protocols

Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today, we are going to discuss the science and practice of flexibility and stretching. The important thing that I'd like you to know is that flexibility and the process of stretching and getting more flexible involves three major components, neural, meaning of the nervous system, muscular, muscles, and connective tissue. Connective tissue is the stuff that surrounds the neural stuff and the muscular stuff, although it's all kind of weaved together and braided together in complicated ways. Stuff and the muscular stuff, although it's all kind of weaved together and braided together in complicated ways. So, here's a key thing that everyone should know, whether or not you're talking about flexibility or not. Your nervous system controls your muscles. It's what gets your muscles to contract. So within your spinal cord, you have a category of neurons, nerve cells that are called motor neurons. Those neurons release a chemical. That chemical is called acetylcholine. The release of acetylcholine from these nerve cells, these neurons, onto the muscles causes the muscles to contract. And when muscles contract, they are able to move limbs by way of changing the length of the muscle, adjusting the function of connective tissue like tendons and ligaments. Now, within the muscles themselves, there are nerve connections, and these are nerve connections that arise from a different set of neurons in the spinal cord that we call sensory neurons. These spindle connections within the muscle that wrap around the muscle fibers sense the stretch of those muscle fibers. So, now we have two parts to the system that I've described. You've got motor neurons that can cause muscles to contract and shorten, and we have these spindles within the muscles themselves that wrap around the muscle fibers and that information is sent from the muscle back to the spinal cord. It's a form of sensing what's going on in the muscle. Now, why would that be useful? Well, what this does is it creates a situation where if a muscle is stretching too much because the range of motion of a limb is increased too much, then the muscle will contract to bring that limb range of motion into a safe range again. Okay? So, just to clarify, this whole thing looks like a loop, and the essential components of the loop are motor neurons contract muscles, sensory neurons that we call spindles are sensing stretch within the muscles, and if a given muscle is elongating because of the increased range of motion of a limb, those sensory neurons send an electrical signal into the spinal cord such that there is an activation of the motor neuron, which by now should make perfect sense as to why that's useful. It then shortens up the muscle. …