What's with the six week rule?

There's been a few people in my classes recovering from injuries and minor operations recently.  Then of course there's the mums who are recovering from childbirth - considered a trauma whatever experience they have had!  But despite the range of severity and site of injuries, there seems to be a six week rule - no returning to exercise until after six weeks .  What's so special about six weeks?

Stages of Wound Healing

The answer lies in the four stages of wound healing.  Tissue is the same no matter who you are or what has happened and it will go through the same process every time.

1. Haemostasis - this is all about stopping the bleeding and forming a clot.  It happens immediately
2. Inflammation - this is the stage of fighting infection and keeping the wound clean.  There is increased blood flow to the wound - resulting in redness and heat.  There is likely to be pain, swelling and possibly pus.  This lasts for 4-6 days.
3. Proliferation - new skin is formed over the surface, whilst tissue is rebuilding underneath. This pulls the wound closer. This starts after 3-5 days and can last for 2-3 weeks
4. Remodelling - changes to the tissue strength and number of blood vessels serving it.  This is when a scar starts to go paler and flatter.  The process starts 2-3 weeks after injury, once the wound has closed, and can last up to 2 years!

These stages are not distinct but  instead overlap, so there is some variation in healing times.  6 weeks means that all the early stages have completed and the remodelling phase is well under way. However, it will take up to a year and possibly longer to return to full strength and function.  And scar tissue is only 80% as strong as the original tissue.  This is worth bearing in  mind when you are returning to exercise after an injury and after childbirth.  At 6 weeks healing is not completed, so you need to begin gradually and listen to your body - don't try to get back to your previous level straight away!