Posted by: tom.guerry (tom.guerry@kp.org) on Sun Dec 2 12:55:42 2001

Jack made some extremely illuminating posts last month (as usual?).See especially driving leg and arm/handstrength(with rql) and the posts related to contact point and staying inside the ball.I think I am starting to understand the linkage and shoulder turn concepts better.

Contact point-

Timing is most important in determining contact point.This is a key point.I believe the rotational swing is the best biomechanical solution for hitting successfully because TIMING is of the essence.Timing errors are minimized by the shortest path from launch to contact and by travelling this path as quickly as possible.The body's motor system can anticipate the duration of the movement more accurately at maximum batspeed because the duration of the swing from launch to contact is more consistent/predictable.This argues for optimizing the blend of short swing,maximum batspeed.

Driving leg-

Reinforcing rql's description of how to use both legs to set up a stable axis of rotation from launch to contact.

Staying inside the ball-

Importance of shoulder rotation all the way to contact.This is equated with "staying linked " to body rotation all the way to contact.My interpretation is that this is mainly accomplished by maintaining the circular handpath.For "linkage" think "circular handpath"/avoidance of "premature extension" which would cause "loss of connection" which means you see premature extension drain all energy prematurely out of the torso with the shoulder turn stopping 1 to 2 frames before contact.In this case,the energy goes into casting the hands and pushing the knob of the bat rather than driving the turning/angular acceleration of the bat.This limits batspeed.

Jack's initial response about staying inside the ball also gives vital information about how adjustments are made (11/19):"...for the rotational hitter the amount of shoulder rotation determines how wide the hands are cast--Full shoulder rotation at contact+ a tight hand path--Less shoulder rotation and allowing the lead arm to cast away from the chest = a wider path".My interpretation of this is that these are equivalent to the "low load"(tight hand path) and "high load"(wider handpath)situations.The body rotates faster with less drag(low load) when the mass is closer to the center of rotation as in the case of the spinning figure skater(conservation of angular momentum).I believe what Jack has observed is that thee simplest way for the body to make the full range of load adjustments to cover the range of pitch location/velocity is by initiating the swing with top hand torque,then controlling the "load" of the swing by when(timing) torso turn is started("launch").When the inside location is recognized,the hips start decelerating early which starts the torso driving the hand path while the mass of the bat is close to the body(center of rotation).When the outside location is recognized,tophand torque proceeds longer before "launch" creating a higher load situation(bathead further out) and less torso turn by contact.This brings up the question of "When do the hands/lead arm cast away from the chest?" In the "high load"/"top hand torque"/outside location situation,I think it is still important to maintain the circular handpath("keep the hands in") until the bat head has fired almost to extension.Then when the lead arm/hands cast,the final draining of energy out of the torso(torso turn stops)will create more batspeed(angular velocity of bathead) and not be wasted pushing the knob of the bat out.Instead,the bat will pull the hands with it to extension resulting in further bathead acceleration until the arms are fully extended.

Theoretically,this fairly consistent method of adjustment would create fewer automatic/ballistic motor programs(more similar set of learned motor program patterns with same relative timing) for the body/brain to master,further reducing the hitter's reaction time(hitter can function better in spite of reduced reaction time since he has fewer choices to match).

Arm hand strength-

Need the ability to apply hand torque(maintain timing accuracy) and maintain the circular handpath(stay linked) as lots of energy flows through.

Criticism appreciated.