Bone, not adrenaline, drives fight or flight response

by Columbia University Irving Medical Center
"The research revealed that the skeleton releases osteocalcin, which travels through the bloodstream to affect the functions of the biology of the pancreas, the brain, muscles, and other organs.

A series of studies since then have shown that osteocalcin helps regulate metabolism by increasing the ability of cells to take in glucose, improves memory, and helps animals run faster with greater endurance."

Muscle Pain: It May Actually Be Your Fascia

by John Hopkins Medicine
"Fascia is a thin casing of connective tissue that surrounds and holds every organ, blood vessel, bone, nerve fiber and muscle in place. The tissue does more than provide internal structure; fascia has nerves that make it almost as sensitive as skin. When stressed, it tightens up."

Does Stretching increase flexibility?

by Tia Ghose
"...making a habit of stretching will not create a sustained lengthening of the muscle or fibers. Muscle tissue attaches at fixed points in the bone, so the entire muscle complex can't get permanently longer. And if one likens muscle tissue to a rubber band, it would not be a good thing for the muscle to get permanently stretched out, as that would mean a decrease in its elasticity."