Medical Definition of Z LINE. : any of the dark bands across a striated muscle fiber that mark the junction of actin filaments in adjacent sarcomeres.Britannica.com: Encyclopedia article about Z line.efinition of Z LINE. : any of the dark thin bands across a striated muscle fiber that mark the junction of actin filaments in adjacent sarcomeres. ADVERTISEMENT.
The average fb speed in the MLB is 91-92ish. Catchers compete with this when trying to throw down a runner at 90ish. The average throw speed from third base is 80 MPH. As for the rest of the positions I am not sure of the exact average, but it is not as fast or faster than pitch speed.
Exit speed is generally faster than bat speed. A 20% variance would be a very rough rule of thumb. The formula is exit speed=q*(pitch speed) + (1+q)*(bat speed) where q is roughly 0.2 for a wood bat. Average MLB fastball speed is 91 mph out of the hand, and 83 mph at the plate. Example: MLB average exit speed is 103 mph, bat speed ranges roughly from 70-85 mph. Wood bats generate a lower exit speed than a non-wood bat.