You’re correct, InnerAthlete … perhaps my language was a bit clumsy.
Synovial fluid indeed lubricates the joints. It also provides much-needed nutrition to the interior areas of the joint capsules. But from where does this nutrition come? The blood stream. And where do waste products from the joint capsules go? The blood stream.
But there is no direct blood supply to the joint capsules themselves. In the end joints get nutrition from the blood stream via diffusion through several layers of tissue, beginning with the capillaries, and all this happens thanks to movement. The heart itself will not pump blood out of the capillaries into surrounding tissues. Movement causes contraction of the capillaries, which opens tiny valves, freeing fresh blood supply, which then diffuses nutrients into the joints and waste products out.
Quoting the book, Management of Common Musculoskeletal Disorders:
“Intermittent compression and distraction of joint surfaces must occur for an adequate exchange of nutrients and waste products to take place … The three primary machanisms by which synovial joints undergo normal compression and distraction are the following: 1) Weight bearing in lower extremeties and spinal joints, 2) Intermittent contraction of muscles crossing a joint, and 3) Twisting and untwisting of the joint capsule as the joint moves toward and away from the close-packed position.”
The joint mobility work indicated in a program like CST, and an effective combination of strength training (particularly movements like the squat, the deadlift, etc.) and mixed-mode yoga posture practice are in my humble opinion, the best way to maintain comfortable stability for life.
Glad to have found this thread …