Posted by: Mike Myers (mike.myers@bellnexxia.com) on Mon Jan 5 23:15:31 2004

Jack,
>
> >>> I believe Coach's contention is the upper torso and arms, in unison, provide tremendous torque, which ultimately drive loose legs and hips with inertia.
>
> He suggests, by tensing the legs, one can only introduce possible impedance to loose lower swivel motion. Leg action, in this sense, is explained as an indirect result of hip swivel, and small balance tuning.
>
> There is some validity, if one can assert leg muscle power is simply too slow/underdeveloped to assist in hip drive, and that attempts to do so reduce fluid motion.
>
> From my experience, however, the optimal approach is to heavily utilize the massive higher leg muscles (upper thighs and groin). These should -snap- initially. Lower muscles (calfs and ankles) are loose and provide only light balance.
>
> This allows one to benefit from the most powerful leg muscle, while limiting concerns for timing of other loose connected tissue.
>
> (Ideally, if one were fast enough, one could recruit all leg muscles - but transfer timing would be difficult. In order for all muscles to contribute maximally to batspeed, they must be fired and unfired at at high speed, and in a sequence directly related to transfer distance from bathead.) <<<
>
> Hi Mike
>
> You stated, “There is some validity, if one can assert leg muscle power is simply too slow/underdeveloped to assist in hip drive, and that attempts to do so reduce fluid motion.” – Is this a miss-print or do you actually believe this? If you do believe it, how do you justify your next statement. –“ From my experience, however, the optimal approach is to heavily utilize the massive higher leg muscles (upper thighs and groin).”
>
> Why would you think the calf muscles are slower to react than the thigh muscles? Do you (or Coach C) have any evidence (published) to support these contentions?
>
> Jack Mankin
>
Jack,

My explanation is simple. I believe powerful leg drive is a fundamental component of the successful baseball swing.

The question is: How does one recruit leg muscle fibres to maximally drive hips (and overall resultant batspeed)?

In my experience, lower leg muscles (calves, and particularly ankles) are simply too small and remote to contribute significant power to the bat at the time it is required. Rather, employing these muscles strenuously has a dampening effect on overall power transfer since inertia must pull more rigid mass (lower limbs) in a circular arc.

My theory is similar to your loose wrist theory, where you debunk direct wrist muscle flexing as an unwarranted impedance to overall power transfer through the joint. I believe the small lower leg muscle group is best suited for fine balance control, but little more.

However, I am flexible, in that I respect we are all in various states of muscle development. I can envision one with exceptionally strong calves being able to utilize these muscles efficiently. This depends somewhat on the individual, however, I am less convinced of ankle muscle contribution. This grouping is just too small and remote to significantly drive the bathead.

Calf and ankle muscles are necessarily slower to react than thigh muscles since they are located approximately 25% further from the brainstem.

See http://www.rwc.uc.edu/koehler/biophys/4d.html

This article suggests the speed of propogation for mammalian motor neurons is 10-120m/s. Assume maximum speed, and calf and thigh are 0.5m apart. Then it takes 0.5/120=4.2ms longer for the calf to receive the signal. For a 90mph (40.2m/s) fastball, thats 0.17m.

A signal delay in which a pitch travels 17cm is fairly significant.

Regards,
Mike.