THE BOOK--Playing The Percentages In Baseball

I always felt like my swing was smoother because I played so much wiffleball when I was a kid.  My older brother would bat left handed when we played to make it more even, and he ended up with a much nicer looking, smoother left handed swing. 

I don’t know if this is at all related to the study.

I remember a long while back a very similar bit circulated around my golf circles that taking full speed practice swings with your driver caused you lose a small amount of distance, which seems directly related to this. It sounded totally believable, and I’ve always taken smooth/floaty practice swings and not used donuts/weights in the on deck circle ever since.

Good luck telling MLBers not to use their weights though. Haha…

Dr. Coop DeRenne’s book echoes these findings as well; he’s done tons of studies on them.

This is known in weightlifting circles and has to do with training your recruitment of muscle fibers.  Moving weight at fast speeds is useful for both slow and fast movements (think power cleans and snatches) while moving weight at slow speeds is mostly useful for slow movements (think deadlifts).  The weight of the bat in this case merely controls how fast you can move it.  By swinging it more slowly (even with max effort) you are training the slower movement. 

I’d be interested to see a study where the same bat was swung at different speeds.  That would add additional evidence to my claims above.

A common bat speed training drill among rec league softball players involves alternating full-effort swings with a heavier-than-normal bat and a lighter-than-normal bat (and then finishing the session with the regular weight bat).

A typical routine is described here (see the bottom of the page):

http://www.bigcat844.com/increasing_bat_speed.html

These studies assume that certain basic strength requirements are met. So when you see someone say their little boy Johnny benefited from swinging weighted bats, the range of explanations is a). Johnny did not get better, b). Johnny was a weakling, or c). another factor(s) is responsible.

I hate seeing people training with overweighted equipment because it just doesn’t make any sense. All you have to do is stop and think about it for a moment to realize it’s illogical.