Lumbopelvic control and pitching performance of professional baseball pitchers.

Chaudhari AM, McKenzie CS, Borchers JR, Best TM.J Strength Cond Res. 2011 Aug;25(8):2127-32.

Baseball is a game that is unique for a variety of reasons, all of which capture our attention. One item unique to baseball is the repeated overhand throwing motion, which produces massive forces and angular velocities generated throughout the body. During the overhead throw the pitchers consistently use a single leg stance to deliver the pitch. Therefore, pelvic control is an important aspect of the throwing motion and deficits can disrupt the kinetic chain leading to decreases in performance and even injury. Identifying and addressing these deficits, understanding how they affect the kinetic chain and improving performance could collectively mean the difference between a team getting the win or the loss. The purpose of this study was to determine the relationship between (LP) control and the success of elite level pitchers. For this study a specific device called the “Level-Belt” was created. It consists of an accelerometer-based sensor on a belt situated at the height of the ASIS and PSIS. The device then captures AP pelvic tilt relative to the horizon. All subjects self-identified their neutral LP position, which included their weight being evenly distributed across both feet. Each subject then lifted their stride leg foot approximately 10 cm off of the ground, held that position for 2 seconds, and then returned to the start position. In order to eliminate a learning effect, each subject performed only one trial unless they stumbled on their first attempt. This study examined the following variables and their relationship to LP control: walk plus hits per inning pitched (WHIP), innings pitched (IP), batting average against the pitcher (BAA), strikeouts/inning (Kin), walks/inning (Bbin), and injures during the season. For this study 48 male minor-league baseball players (mean age 22.5+2.1 years) were identified as candidates during the final week of spring training over 2 consecutive seasons. In an effort to eliminate skewed results based upon a lack of competition, all subjects were entered into the study by virtue of having pitched 50 or more innings. The median score (absolute value) was 7° of pelvic tilt and this was used to split the subjects into 2 groups: subjects with greater than 7° of tilt and subjects with less, than 7° of pelvic tilt. Interestingly, there was a significant relationship between WHIP and IP. The group with less than 7° of tilt demonstrated superior accuracy WHIP and endurance IP. While there wasn’t statistical significance for any of the other categories, the group with superior LP control trended towards having better results in all of them (BAA, Kin, BBin and injury incidence).

This study is important to us as clinicians for a handful of reasons. The use of the Level-Belt and the task that the athletes performed are very functional. While other tests are out there to asses LP control, none of them are done in a standing position. Trying to examine LP control in a supine position does not translate well to something as dynamic as the baseball pitch. Based on the results of the study, subjects with better LP control were able to locate their pitches more accurately (WHIP) making them more efficient (IP), which in turn allowed the completion of more innings. An area of interest that is going to require further investigation is motion in other planes. This study only looked at sagittal plane motion, but the baseball pitch is a highly dynamic activity occurring in multiple planes. While much work still needs to be done, this study does a great job at initiating and determining the effect LP control might have on the baseball pitch. What are your thoughts on pelvic control in overhead athletes? Is it as important as we think? How do you assess it? How do you incorporate it into rehab?

Written by: Mark Rice
Reviewed by: Stephen Thomas