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.
This is often due to the tendons and bursae in the joints. Tendons are bands of thick tissue that attach muscles to bone but they lack elasticity, and can be easily pulled during movement. Tendonitis is the inflammation or irritation of the tendon(s); the condition can vary and may result in aches, pain and stiffness.