Tendons may be classified as intrasynovial or extrasynovial based upon their anatomic location. We studied the physical properties of extrasynovial and intrasynovial tendons. Extrasynovial tendon has a rougher surface and higher friction than intrasynovial tendon. A number of carbodiimide derivatized biomaterials were developed to modify the irregular surface of an extrasynovial tendon to mimic the smooth surface of an intrasynovial tendon. We found that carbodiimide derivatized hyaluronic acid-gelatin (cd-HA-gelatin) chemically bonded to the extrasynovial tendon surface and optimally reduced gliding resistance in vitro. This biosynthetic, biomimetic modification of the extrasynovial tendon surface may prove to be a useful clinical product.