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.
95 mph is considered a plus fastball velocity, and +97-98 mph  a plus, plus velocity.    the 90 range is a good speed for an mlb pitcher. some pitchers do  pitch in the high 80s though.real good pitchers pitch 100mph too   Randy Johnson threw a 103 mph fastball.k, soo a good softball speed for 12-13 is 50 mph the really good pitchers throw around 55. When you turn 16-17 your goal should be 55 mph. Collage is high 60 to low 70. I thi â¦ nk high school the really good pitchers will throw around the 60 mph.