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.
Pitchers in this age group are playing in the Majors division in Little League. The average fastball is between 50-60 mph. However, at this age the players may start to hit puberty, therefore it is not uncommon to see a pitcher throwing near 70 mph.0 Years Old and Younger. The average fastball velocity for pitchers 10 years old and younger is between 40-50 mph. The average change up speed for this age group is about 10 mph slower, putting the velocity between 30-40 mph. 11 and 12 Year Olds.