11/06/2025
Tendonitis is really a piece of work. It lingers way longer than you think it should and it comes on so much easier now that you’re older.
A stiff tendon will not stretch, so the muscle attached to that tendon will experience more eccentric loading (lengthening under tension), often resulting in muscle injury and tendinopathies.
Tendon injuries can be acute or chronic, and caused by intrinsic or extrinsic factors.
Tendinopathy is an overactive, failed healing response, with haphazard and weird tenocytes, the cells truly change!
Tendons that have tendonitis have an increased rate of matrix remodeling, which makes a mechanically less stable tendon that is a total we**ie. It literally is stiff, but weak.
Now here’s the weird part: inflammation is really only at the beginning of the process. That’s why steroids and NSAIDs aren’t working.
So how do we fix it? The best thing we know at this time is: eccentric exercise. Eccentric exercises have the most evidence of effectiveness in the treatment of tendonitis.
What is eccentric strengthening?
An eccentric muscle contraction is when a muscle lengthens under tension, typically as an external force overcomes the muscle’s resistance. The muscle gets longer while it’s still generating force - so for your bicep curl, it’s when you lower the weight back down. For calf raises, it’s when you lower back down.
Focusing on that is one important piece. I still think there is something we don’t understand at the cellular level with tendinitis. I almost acts like it is metabolic related to some extent. We don’t fully understand the tendons and muscles like you think. We spent decades on arthritis and ACLs.
