Effect of Excessive Contralateral Trunk Tilt (HS Pitchers)

[Can_of_corn]

I am not going to pretend I understand the totality of the article but I figure some of the folks here would appreciate it.

http://ajs.sagepub.com/content/early/2013/07/24/0363546513496547.abstract?rss=1

Purpose: To investigate the effects of excessive contralateral trunk tilt, a common technique identifiable by video observation, on pitching biomechanics and performance in high school baseball pitchers. The hypothesis was that this strategy is associated with greater joint loading and poor pitching performance.

[weams]

I don't understand it either, but you know I did the Biomechanics stuff.

[Tony-OH]

Appears to be math involved. I'm out and will wait on the Cliff notes version.

[Can_of_corn]

Appears to be math involved. I'm out and will wait on the Cliff notes version.

Main reason I posted was to get someone to explain it to me.

[weams]

and experienced a greater elbow proximal force

"That is all Ye know on earth, and all ye need to know."

[TGO]

I hope the full text has diagrams.

[24fps]

I'm going to make a guess (emphasis on guess)

I think contralateral means if a pitcher's hips are rotating counter-clockwise, his shoulders are rotating clockwise. Perhaps in this article it could also mean that during the downward phase of the pitching motion his hips could be rotating left while his shoulders are still rotated right (in the case of a RH pitcher) for a part or most of the throwing motion and this is a contributor to excessive joint loading. Imagine a rod extending down the center of his spine (serious golfers will recognize the mental image) acting as a rotational axis. "Contralateral trunk tilt" might mean that imaginary rod is bent - probably left or right in relation to the pelvis.

I wonder how many people on the planet actually understand this based on the language and math alone. I really wish some diagrams were included because I bet a lot of people here would understand this well enough in that case.

I would love it if somebody who actually knows what he's talking about would weigh in because this is interesting.

[cmurter]

Interesting article, but left much to be desired IMO.

First of all, contralateral is the anatomical term for "opposite" side of the body (in contrast, ipsilateral means the same side). Therefore, contralateral trunk tilt is simply the shoulders of a RHP being oriented to the left side of the pelvis, and vice versa for LHP when the ball is pitched. This figure from the full text of the article (free on campus:thumbsup1:) explains it:

What this paper looked at is the average velocity and the proximal joint loading (the amount of force applied across the shoulder and elbow joints) of pitchers who used this type of delivery versus those who did not. In this study, 31/72 pitchers had contralateral trunk tilt, while 41/72 did not. What they found was that pitchers who pitched with contralateral trunk tilt achieved a consistently (but not statistically significant) higher velocity (about 3.3 mph). They also found that this conferred a statistically significant increased load on both the shoulder and elbow joints (about 10% greater force).

The author made a point of noting that they did not correlate these findings with injury risk, but merely performance parameters. Now, one might assume that greater joint loading correlates with a greater injury risk, but this is not necessarily true, and it is a much harder study to perform with a number of additional confounding variables. That said, it is also the point at which this data becomes relevant to amateur pitching coaches and team trainers/doctors.

If you guys have any other questions about this article, I'd be happy to answer them.

[Tony-OH]

Interesting article, but left much to be desired IMO.

First of all, contralateral is the anatomical term for "opposite" side of the body (in contrast, ipsilateral means the same side). Therefore, contralateral trunk tilt is simply the shoulders of a RHP being oriented to the left side of the pelvis, and vice versa for LHP when the ball is pitched. This figure from the full text of the article (free on campus:thumbsup1:) explains it:

What this paper looked at is the average velocity and the proximal joint loading (the amount of force applied across the shoulder and elbow joints) of pitchers who used this type of delivery versus those who did not. In this study, 31/72 pitchers had contralateral trunk tilt, while 41/72 did not. What they found was that pitchers who pitched with contralateral trunk tilt achieved a consistently (but not statistically significant) higher velocity (about 3.3 mph). They also found that this conferred a statistically significant increased load on both the shoulder and elbow joints (about 10% greater force).

The author made a point of noting that they did not correlate these findings with injury risk, but merely performance parameters. Now, one might assume that greater joint loading correlates with a greater injury risk, but this is not necessarily true, and it is a much harder study to perform with a number of additional confounding variables. That said, it is also the point at which this data becomes relevant to amateur pitching coaches and team trainers/doctors.

If you guys have any other questions about this article, I'd be happy to answer them.

Finally, something I can understand. Thanks for breaking that down and the picture helped as well. Rep your way.

[TGO]

That's awesome, thanks so much for posting.

One of the main reasons for tilting away from the arm side is to allow for a more "over the top" delivery, right?

[cmurter]

That's awesome, thanks so much for posting.

One of the main reasons for tilting away from the arm side is to allow for a more "over the top" delivery, right?

Sort-of. In fact, the authors noted that this allowed for a more "upright" delivery:

pitchers with excessive contralateral trunk tilt demonstrated less forward flexion of the upper torso at stride foot contact and utilized more trunk movement in the frontal plane and less movement in the transverse plane during the arm-cocking and acceleration phases of pitching.

For reference, the planes discussed above are as follows:

I also found this comment interesting as far as a reason for developing this type of delivery:

trunk movement in the frontal plane (contralateral flexion) is assisted by the gravitational force, whereas trunk movement in the transverse plane (rotation) is mostly generated using the hip and trunk musculature. It is possible that excessive contralateral trunk tilt is a compensatory pattern adopted by pitchers who cannot produce trunk rotation because of previous injuries or weakness of the hip and abdominal musculature.

[mark_beckens]

http://www.spts.org/assets/files/Special%20Interest%20Groups/2011%20Shoulder%20SIG%20Winter%20Newsletter.pdf?AspxAutoDetectCookieSupport=1

I found this much easier to read and understand. Very interesting study.

[mark_beckens]

Interesting article, but left much to be desired IMO.

First of all, contralateral is the anatomical term for "opposite" side of the body (in contrast, ipsilateral means the same side). Therefore, contralateral trunk tilt is simply the shoulders of a RHP being oriented to the left side of the pelvis, and vice versa for LHP when the ball is pitched. This figure from the full text of the article (free on campus:thumbsup1:) explains it:

What this paper looked at is the average velocity and the proximal joint loading (the amount of force applied across the shoulder and elbow joints) of pitchers who used this type of delivery versus those who did not. In this study, 31/72 pitchers had contralateral trunk tilt, while 41/72 did not. What they found was that pitchers who pitched with contralateral trunk tilt achieved a consistently (but not statistically significant) higher velocity (about 3.3 mph). They also found that this conferred a statistically significant increased load on both the shoulder and elbow joints (about 10% greater force).

The author made a point of noting that they did not correlate these findings with injury risk, but merely performance parameters. Now, one might assume that greater joint loading correlates with a greater injury risk, but this is not necessarily true, and it is a much harder study to perform with a number of additional confounding variables. That said, it is also the point at which this data becomes relevant to amateur pitching coaches and team trainers/doctors.

If you guys have any other questions about this article, I'd be happy to answer them.

I would think 72 is too small a sample size to determine much about speed variations. Also to get a true speed difference

you would have to have a pitcher throw both ways and then see what the difference is.

[bobmc]

So Tillman is good right - Gausman?

[cmurter]

I would think 72 is too small a sample size to determine much about speed variations. Also to get a true speed difference

you would have to have a pitcher throw both ways and then see what the difference is.

Right, the sample was relatively small, which is why the velocity findings, while consistently higher were not statistically significant. Given a larger sample size, it is likely that the difference would then become statistically significant.

To their credit, the authors noted that the two groups did not significantly differ in age, height, weight, or years of pitching experience, to keep the study as even as possible. The American Journal of Sports Medicine thought it was a good enough study to "see what the difference is", though