Stress reaction, Stress Fracture, and full on Fracture; These injuries are the topics of todays solo episode.
Bone is a metabolically active tissue with many functions. The obvious function is its structural function; providing our bodies with support and giving a framework for our contractile tissues, muscles, to act upon. But bone does far more than this. Our bones are major storage sites for calcium, magnesium, and a major production site for red blood cells. The storage aspect is a very relevant aspect in relation to injury from repetitive stressors like running. Running not only stresses our bones physically, but metabolically as well because of the many roles that calcium plays in the body.
Bone Stress Injury:
- Bones are continuously evolving structures with multiple functions.
- Structural function: scaffolding of the human body upon with our contractile tissues such as muscles operate
- Storage function: storing minerals such as calcium, magnesium, phosphorus, and other vital minerals. We also store energy in the form of fat with yellow bone marrow
- Regulation: regulation of calcium occurs with bones as a storage site. When calcium levels in the blood drop, specialized bone cells called osteocytes reabsorb bone to release the stored calcium, thus maintaining blood levels of calcium
- Reason being that calcium is responsible for many functions in the body besides its most widely known role as what helps us build strong bones. It is also is vital to proper functioning of nerves and muscle tissue.
- Production function: production of red blood cells within our red bone marrow.
- There is a continuous process of bone mineralization, and resorption that is occurring
- These processes are based on available nutrients and energy availability, as well as stimuli applied to bones
- If we do not have the foundational components necessary for bone mineralization, bone will not be mineralized appropriately. Conversely, if bone has all of the necessary nutrients and ingredients necessary, but does not receive adequate stimuli, bone will not be mineralized appropriately.
Why Bone stress injury happens:
- Repetitive microstrain due to loading cycles (i.e. running) leading to microdamage formation
- Osteoclasts come in a debride the damaged bone
- Followed by osteoblasts laying down new bone
- The gap between these is when bone stress injury happens
- Low energy availability reduces activity of osteoblastic cells, thus increasing the size of the gap between osteoclast resorption and osteoblast bone formation
- Internal vs external forces
- Peak impact forces were previously associated with bone load
- However internal forces generate much more force than external forces
Let us know via email at artofprevention.info@gmail.com if you would like the show notes or references for anything from the episode!
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