Posts tagged anatomy
Skeletal System - Anatomy 101 Refresher
Front View (Anterior)
Back View (Posterior)
(via: yogapractice)
What Happens When We Stretch?
This is great!
What exactly happens when we stretch? We all know something gives. The longer we reach for our toes, the easier it is to grasp them.
What we’ve learned through science is that it isn’t just one thing. Stretching is actually pretty dang complicated.
First the Anatomy
Each muscle fiber is wrapped up in fascia, a material a little like the plastic wrap you could see surrounding a leftover chicken leg in the fridge. Each individual muscle fiber wrapped up in its fascia is then collected into a group with another coating of fascia holding the group together. Then several of those groups of muscle fibers are bundled together in one big group of muscle surrounded by a bigger, thicker layer of fascia.
As the muscle nears a bone, it thins and becomes tapered. The fascia covering each fiber as well as that surrounding the groups of fibers continues and becomes a tendon that forms the connection of muscle to bone. Scientists call this entire structure the muscle-tendon complex. It’s considered one unit because muscle and connective tissue (fascia and tendons) are so intimately connected and intertwined that studying only one or the other is difficult. Having said that, they’ve been able to tease out what is happening to each of them when we stretch.
The Muscle Component
Stretching muscle causes a reflex mechanism in the spinal cord– sort of like the reflex a doctor elicits when she taps your knee and your leg jerks. Sensitive receptors known as muscle spindles are located throughout the length of the muscle. Muscle spindles note a change in muscle length during a stretch as well as how fast the stretch has occurred. They send this information to the spine. That triggers the stretch reflex which attempts to resist the change in muscle length by causing the stretched muscle to contract. The more sudden the change in muscle length, the stronger the muscle contractions will be. (And that is one reason you want to go slowly into a stretch without any rapid sudden movement.) This reflex helps to maintain muscle tone and upright posture and to protect the body from injury. The longer you hold an asana and stretch the muscle, the less the muscle spindles can do their job. They only work for a short while. After time, their effect goes away. When that happens, you get a little more length during the stretch because the muscle stops contracting.
