Influence of pelvis rotation styles on baseball pitching mec


#1

Interesting read, not an easy read though. Am I interpreting this correctly that the last statement suggests that the more your hips are open at foot plant the lower the velocity?

Ed :?:

Sports Biomech. 2004 Jan;3(1):67-83.

Influence of pelvis rotation styles on baseball pitching mechanics.
Wight J, Richards J, Hall S.

Department of Health, Nutrition, and Exercise Sciences, University of Delaware, Newark, Delaware, USA.

Efficient, sequential timing is essential for upper level pitching. Interestingly, pitchers vary considerably in timing related elements of pitching style including pelvis rotation, arm cocking, stride leg behaviour, and pitch delivery time. The purpose of this study was to determine whether relationships exist among these elements by examining the overall style of pitchers exhibiting different pelvis rotation patterns. Pitching styles were defined by pelvis orientation at the instant of stride foot contact. Pitchers demonstrating a pelvis orientation greater than 30 degrees were designated as ‘early rotators’, while pitchers demonstrating a pelvis orientation less than 30 degrees were designated as ‘late rotators’. Kinematic and temporal differences were associated with the two styles. During the arm cocking phase, early rotators showed significantly greater shoulder external rotation at the instant of stride foot contact, earlier occurrence of maximum pelvis rotation angular velocity, and shorter time taken to complete the phase. However, by the instant of maximum shoulder external rotation, early and late rotators appeared remarkably similar as no significant difference occurred in pelvis and arm orientations. Therefore, it appears that early and late rotators used different methods to achieve similar results, including throwing velocity. Significant differences in throwing arm kinetics were also found for 10 of the 11 measures in the study. As the pelvis assumed a more open position at stride foot contact, maximum kinetic values were found to both decrease in magnitude and occur at an earlier time within the pitch.


#2

yes because you can rotate your hips faster against a braced front leg. What I do is let the weight transfer from my back leg to the front, when I do that the back leg lightens up enough for me to roll over my laces (rotate my hips). Also, waiting until the moment I land helps me keep my shoulders closed.

Now all this happens within milliseconds, its all feel and timing…as soon as I feel my back foot lighten up I know its time to roll over my foot, then my upper body uncoils fast to square up with the hips.

Starting to rotate the hips right before the instant the front leg braces is ok as long as you can keep your shoulders closed. Somebody without the abdominal strength or flexibility can easily create a habit of opening the shoulders a little bit before landing and just that little bit can be the difference in velocity vs somebody who keeps their shoulders closed into landing and rotates “late”.


#3

I think the last statement is basically saying that early hip rotation into foot plant robs you of energy to put into the baseball. If you can’t make up for that with your arm then, yes, lower velocity is the result.

But I’m not sure I agree with the premise that a more open pelvis orientation at foot contact automatically indicates the timing of the rotation because that would seem to imply equal flexibility among pitchers and equal pelvis rotational velocity. If you open more by foot contact, does that mean you opened earlier? Or faster? If you open less, does that mean you opened later? Or slower? Or at the same time but your lack of flexibility limited how far you could rotate?


#4

Well think about it…the idea is to get rotational force aka torque. The more open you are before weight transfer (brace the front leg) the less there is to rotate. More mass to rotate would create more force. Less mass to rotate, less force.

Does that make any sense?


#5

[quote=“Roger”]I think the last statement is basically saying that early hip rotation into foot plant robs you of energy to put into the baseball. If you can’t make up for that with your arm then, yes, lower velocity is the result.

But I’m not sure I agree with the premise that a more open pelvis orientation at foot contact automatically indicates the timing of the rotation because that would seem to imply equal flexibility among pitchers and equal pelvis rotational velocity. If you open more by foot contact, does that mean you opened earlier? Or faster? If you open less, does that mean you opened later? Or slower? Or at the same time but your lack of flexibility limited how far you could rotate?[/quote]

Roger

Do you think this is related to what Tom House refers to as different guys with different ways to create velocity? He terms some guys “big hips little shoulders” and others “little hips big shoulders”? At foot strike Clemens’ pelvis is rotated significantly more (big hips) than Sabathia (big shoulders) yet both achieve similar degrees of hip and shoulder separation and similar velocities. Their timing is just different and unique to their motion.


#6

[quote=“tonyjh34”]The more open you are before weight transfer (brace the front leg) the less there is to rotate. More mass to rotate would create more force. Less mass to rotate, less force.[/quote]Hip rotation isn’t about so much about mass, rather about the creation of the stretch in the torso and the subsequent unload of that loading process, fueling shoulder rotation. Timing is crucial in all of this. If you open too early, you risk losing the benefits of the Stretch Shortening Cycle (SSC) and the elastic nature of connective tissues. This points back to what Roger said about various pitchers having differing flexibility. The point is not so much on the amount of hip to shoulder separation there is but on the fact that you get to your particular body’s effective amount for transfer of energy into the torso and then the shoulders. The timing of this, as I noted above, is crucial.


#7

[quote=“JP”]Roger

Do you think this is related to what Tom House refers to as different guys with different ways to create velocity? He terms some guys “big hips little shoulders” and others “little hips big shoulders”? At foot strike Clemens’ pelvis is rotated significantly more (big hips) than Sabathia (big shoulders) yet both achieve similar degrees of hip and shoulder separation and similar velocities. Their timing is just different and unique to their motion.[/quote]

Yes, I do. The article above doesn’t seem to take into account these differences between pitchers.


#8

Great explanation, DM.