Re: Re: Re: Re: Re: Re: F=MA by Steve
Posted by: SteveT (
) on Tue Jan 11 08:25:24 2000
Here is the abstract from an old study on grip. I don't have the entire article, but I will soon. Until then, the only speculation I can give is that the trampoline effect is lost without a grip (the al. Bats performed worse than wood without a grip.) Yes, the ball is on an aluminum bat longer, and the resonant frequency is different. It is possible that the difference is enough so that the wave reaches the hands before the ball leaves. But I would caution against assuming that today's bats would perform the same. There is some work going on right now on exit velocity (sorry- can't reveal my sources.)
Med Sci Sports Exerc 1989 Apr;21(2):199-205
Effects of bat composition, grip firmness, and impact location on postimpact ball velocity.
Weyrich AS, Messier SP, Ruhmann BS, Berry MJ
J.B. Snow Biomechanics Laboratory, Department of Health and Sport Science, Wake Forest University, Winston-Salem, NC 27109.
The purpose of this investigation was to examine the effects of bat composition (aluminum and wooden), impact location [center of percussion (COP), center of gravity (COG), and end of the bat (E)], and grip firmness [tight (T) and no tension (NT)] on postimpact ball velocity. With the bats placed alternately in NT and T conditions, baseballs were delivered at a speed of 27.1 m.s-1 from a pitching machine positioned 1.5 m from the bat. High-speed photography (400 fps) was performed using a Locam camera positioned 7.54 m from and perpendicular to the principal plane of ball movement. A three-way ANCOVA revealed significant (P less than 0.01) differences in postimpact ball velocity between the three impact locations, with the COP yielding the greatest values, followed by the COG and E. Moreover, there was a significant (P less than 0.01) grip vs bat interaction. A simple-effects procedure revealed the following results: 1) the T grip produced greater (P less than 0.01) velocities than the NT grip across the aluminum (Al) bat; 2) there was no difference (P greater than 0.01) between the T and NT grips across the wooden (W) bat; 3) the W bat produced greater (P less than 0.01) velocities than the Al bat across the NT grip; and 4) there was
no difference (P greater than 0.01) between the Al and W bats across the T grip.
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