What is the connection between joint hypermobility and tendonitis?

Overstretching tendo: With increased ability for joints to move more than the normal range, the tendons (muscle to bone connectors) and ligaments (bone to bone connecters) get over stretched causing micro tears and inflammation from the excessive range of motion. This is the connection between hyper mobility and inflamed tendons.

Sort of: There is some evidence that those with hypermobilty are at increased risk of sprains and strains, although there also exists some evidence to the contrary. Pathophysiologically speaking, I am not aware of any studies implicating changes in the structure of tendons among individuals with hypermobility. With that said, over stretching and hence injury to tendons theoretically makes sense.