The value of the vertical jump is that it show's a player's ability to burst off the line of scrimmage with lower body strength. That's why the drill is important for linebackers and defensive linemen despite the fact that they, in theory, are not jumping around much trying to defend passes.
Wrist tendonitis, also called tenosynovitis, is a common condition characterized by irritation and inflammation of the tendons around the wrist joint. Many tendons surround the wrist joint. Wrist tendonitis usually affects one of the tendons, but it may also involve two or more.
Tendons normally move smoothly within a tendon sheath with motion of the wrist and fingers. When tendons swell in patients with tendonitis, there is friction between the tendon and the overlying sheath which could lead to swelling and a painful catching sensation and even locking. Ganglions or cysts above the wrist can occur without any trauma.