Membership Spotlight: Alek Diffendaffer

Alek Diffendaffer is from Colorado and currently works at the American Sports Medicine Institute as a Sports Biomechanist. In his current role, he runs the motion capture lab and leads the data capture, data processing, and data interpretation for athletes injury prevention and performance enhancement. He is passionate about baseball and sports, and feels very fortunate to tie his education with it.

His favorite place to travel is Bar Harbor, Maine and his favorite food to eat is Mexican. If he could cook anything, it would be Pork Green Chili. His favorite movie is Gone in 60 seconds and if he could have any animal as a pet, it would be an elephant! If allowed to pick any superpower, he would want to fly. Outside of baseball, he likes to partake in lawn care activities and his favorite holiday is Christmas.

MLB Membership Spotlight: Ethan Stewart

Following in the steps from last week, this membership spotlight is also a member of the Major League Baseball community.

Ethan Stewart is the Player Performance Facilitator for the Baltimore Orioles. Along with wortking a full-time job, he is also finishing his PhD. Ethan is currently a doctoral candidate in Neuromechanics/Biomechanics from Mississippi State University.

“While this spring training has definitely been different than most, it has been really good to be back working on the field with our athletes, coaches, and all player development staff. COVID has brought about new challenges in completing the job, but we as an organization, have excelled at adapting to the new “normal”. I am excited to see how our players do as they leave this spring training camp, and I am excited to welcome more of our athletes and staff as the next wave of spring training begins. The tide is rising in the Orioles organization and I am excited to see where it takes us.”

Ethan was born and raised in Kentucky, leading to a life-long love of the Kentucky Wildcats. He was fortunate enough to receive his Bachelors and Masters degree from The University of Kentucky in Kinesiology and Health Promotion. In his role as the Player Performance Facilitator, Ethan is in-charge of data collection and analysis of sports science tools. Along with data-collection, he is in constant communication with athletes, coaches, and all player development staff. His favorite part about the job is the integration of sports science into the daily lives of athletes to help increase their performance on the field and decrease their risk of injury. His love of baseball biomechanics comes from not only his time as a baseball player, but also from his advisor Dr. Robert Shaprio.

If Ethan could travel anywhere, he would go to Jamaica with his wife, Megan Stewart. His favorite thing to eat is boneless chicken wings, while his favorite food to cook is frozen pizza. If he is going to get fancy, he will cook salmon and asparagus. The Other Guys is his favorite movie and Brooklyn 99 is his favorite TV show. If he could have any animal as a pet it would be a Husky, which he already has (Skyler). Given the opportunity to have any superpower, Ethan would choose to have the ability to fly, so he could quickly see his family around the demanding schedule of working in the MLB.

Outside of baseball, Ethan enjoys spending time with his family, being outdoors, or playing a sport (in non-COVID times). His favorite holiday is Christmas, because he loves to give gifts to others. Ethan is lucky to call Megan Stewart his wife, even if she does work for a competing Major League Baseball Organization, the Milwaukee Brewers.

MLB Membership Spotlight: Will Vandenberg

As Major League spring training is coming to a close, we wanted to highlight a member of ABBS who also works in the MLB. To start off this membership spotlight, here is a quote from Will on how spring training has been going.

“Spring training has been unusual this year for sure. In a normal year I spend all of spring training at our facility in Arizona, but this year, given the reduced numbers in camp, our Performance Science team has had to split who’s in person and who’s remote, so I am working from home during major league camp and will be heading down to AZ at the end of the month for minor league camp. I’m looking forward to seeing all of our coaches and players and live baseball for the first time in over a year. Despite most of us being remote during major league camp, it has been really productive. Those of us that are remote have been doing a lot of the computer work, research, and data analysis while our teammates that are in person are having the conversations with the coaches and delivering that information. We’ve also been able to have a lot of the meetings that are normally in person over zoom for the people not in AZ”.

Will grew up in New York and currently works for the Los Angeles Dodgers as a Research Scientist. In his role as a Research Scientist he analyzes biomechanical data to improve player performance of major league and minor league players. He is interested in biomechanics because the body is the perfect machine. He finds it fascinating to analyze how everything is connected and how the laws of physics govern the movement of the body. Wil has always loved baseball, so being able to apply biomechanics to baseball has been the perfect combination of his two passions. The nature of the game also creates two very discrete and specific movements, the pitch and the swing, that are perfect for biomechanical analysis.

His favorite place to travel is Italy and his favorite food is pasta. If he could cook anything, it would be meatballs. His favorite move is V for Vendetta and if he could have any animal as a pet, it would be a dog. His favorite holiday is Christmas. When given the opportunity to have any superpower, Will would choose teleportation. Even in a post COVID world, you would be able to live wherever and still work anywhere! Outside of baseball, Wil likes music. He even got a turn table during quarantine and he has been enjoying the ability to build out his record collection.

Will would like to leave us all with this message, “Just because something is statistically significant does not mean that it is real world significant. And question everything, not everything that applies to other sports applies perfectly to baseball. Other sports can provide ideas and directions to investigate, but things do not translate perfectly from one sport to another”.

Membership Spotlight: Taylor Cortright

Taylor Cortright grew-up in Buffalo, NY and is currently a Physical Therapist at UBMD. For her current role as a Physical Therapist, she treats functional mobility impairments in an outpatient orthopedic setting. Her love of baseball came from her husband, who was a professional baseball pitcher for the Baltimore Orioles and Miami Marlins organizations and is currently a collegiate coach. From years of watching countless games she inherited a strong appreciation for the game and athleticism required to perform it well.

Her favorite place to travel is Siesta Key. She loves to eat pancakes, but her husband does most of the cooking at home! Her favorite movie is Breakfast at Tiffany’s, and if she could have any animal as a pet, it would be a Penguin!! If she could have any superpower, it would be to heal anything. Outside of baseball she likes to play card games and board games. Her favorite holiday is Christmas!

Taylor believes that treating functional mobility impairments and/or improving performance is a fully holistic task. As individuals we must take care of our bodies, minds and spirits if we want the best outcomes.

Membership Spotlight: Tina Stefanovic

Tina was born in Serbia, which is a small country in Eastern Europe, in a city called Cacak. Although she spent most of her childhood there, she moved to the US right after high school. Thanks to an athletic and academic scholarship, She got the opportunity to play volleyball and pursue her undergraduate studies at New York Institute of Technology. She is currently a student at Point Loma Nazarene University pursuing her Master’s degree in Kinesiology and Sport Performance.

She is currently involved with biomechanics research as well as being a teaching assistant and sports science intern. As a biomechanics TA/RA she has enjoyed providing support for the undergraduate and graduate biomechanics lectures and laboratories. She also participates in pitching biomechanics research under Dr. Aguinaldo. This includes setting up and running the MoCap system, collecting the data, and post-processing it. Most of their research focuses on professional MLB teams.  With the Sports Science Internship she conducts athlete monitoring and performance testing using sports science technology for the purposes of performance and injury surveillance as well as work-out optimization

She is really interested in understanding the role biomechanics play in baseball player performance and injury prevention. In her future career, She hopes to implement evidence-based recommendations and biomechanical data to develop models for baseball player evaluation, injury risk assessment, and improvement of on-field movement.

Her favorite place to travel is anywhere in Europe, and she love all kinds of food. Home-made, Serbian food is the best though! She does not have the opportunity to eat a lot of home-made Serbian meals, so she tries to prepare them whenever she can. Her favorite meal to cook would be “sarma” – cabbage leaves stuffed with a mixture of ground meat, rice, and spices. She does not have a favorite movie – She is more of a series kind of person! But she loves watching Serbian movies and getting educated on her country’s history. If she could have any pet, she would have a DOG! Her superpower would be the ability to heal others. Outside of baseball, she loves to coach volleyball! her favorite holiday is Christmas!

Here are some fun facts:
Her dad played professional basketball in their home country and is now a successful basketball coach. He’s the reason why she decided to pursue a collegiate playing and later on coaching career in volleyball.

She played in the NCAA women’s volleyball national championship in 2015.

She had a knee injury that required 2 surgeries.

After graduating with a BS in biomedical engineering, She worked in an orthopedic research lab for 2 years while also working as a program manager for USC women’s volleyball team. These experiences opened up the doors to her master’s program, where She fell in love with biomechanics research!
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Member Updates and Information

Hello Everyone,

We have received some questions regarding the posting of the video from the ISBS/ABBS Baseball & Softball session. We are currently waiting for ISBS to send us the link. Once we have the link we will notify everyone that it has been posted on our website.

Just a reminder, the SABR virtual conference is next week (March 11-14th). We are excited to have a panel of ABBS members discussing the role of biomechanics in MLB.

The ABBS career board is posted on the website and we encourage everyone to post any baseball biomechanics jobs on the page.

We have begun posting the Membership Spotlights weekly on the website and social media accounts. The survey is still open and if you would like to be included in this opportunity, please fill out this Survey Monkey link.

We are continuously adding content and information to our WebsiteFacebookTwitterInstagram, and LinkedIn accounts. Be sure to follow us. If you would like to have your work featured on our social media be sure to send Megan Stewart an email at

Thank you,


ABBS State of the Society

What a dull year 2020 has been. Nothing unusual.

We all wish that were the case, but of course Covid-19 turned our world upside down. I hope you and your family are doing well this holiday season. Here’s wishing for a better year in 2021 for us all. The purpose of this email is to share the first annual State of the Society with you for the American Baseball Biomechanics Society (ABBS). Specifically, I will share some highlights of 2020 and vision for 2021.

With the growth of biomechanics in baseball, I emailed an interest form in January 2020 to biomechanists involved with baseball. Dozens of people expressed interest in joining a society, including 11 who showed strong interest in creating the society. A founding group was formed comprised of these 11 biomechanists: Anthony Brady, Dr. Glenn Fleisig, Ben Hansen, Dr. Bryson Nakamura, Dr. Gretchen Oliver, Dr. Hillary Plummer, Dr. Robert Shapiro, Dr. Jonathan Slowik, Dr. Matt Solomito, Ethan Stewart, and Megan Stewart. During the next few months, this founding group created the society’s name (American Baseball Biomechanics Society), logo, bylawswebsite, and Facebook page. The society also applied for and received 501(c)(3) nonprofit status from the IRS.

The founding group assumed the positions as the Board of Directors in accordance with the bylaws. Glenn Fleisig (President), Gretchen Oliver (Treasurer), Hillary Plummer (Secretary General), Megan Stewart (Vice President of Social Media), and Bryson Nakamura (Vice President of Conferences) were set as the society’s officers. The Board decided to set society membership as free without dues for the first year. Eleven companies provided financial support as founding sponsors: DARI Motion (title sponsor), KinaTraxBertecQualisysAMTIViconDriveline BaseballRapsodoDiamond KineticsProPlayAI, and SMT.

Thanks to the ABBS social media committee, we now have over 1,000 followers on Twitter and Instagram. If you are not yet following ABBS, we encourage you to do so. If you have something you would like tweeted or retweeted by ABBS, tag ABBS or contact Megan Stewart.

The inaugural ABBS conference was held online in July, thanks to the hard work of the board and particularly the conference committee. 949 people registered. This three-day event featured presentations on broad topics like technology and careers in baseball biomechanics and specific studies such as the kinetics of pitching and hitting. Videos of all presentations are archived to view.

By August, ABBS had 150 members. The first annual business meeting for ABBS was held online in August, in conjunction with the annual meeting of the American Society of Biomechanics. The bylaws were ratified and the acting executives and directors were officially elected. A call for two more directors was announced and 10 members were nominated in the nomination period. An election was held online and Dr. Kristen Nicholson and Dr. Ming-Sheng (Matt) Chan were elected onto the board.

baseball biomechanics career board has now been created. If you have a job, internship, academic position, or other opportunity, please post it on this board. This board is specifically for baseball biomechanics positions with MLB organizations, universities, technology companies, institutions, and others.

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Borrowing a biomechanics term, we plan to carry our momentum forward into early 2021. ABBS has partnered with a number of other societies with upcoming meetings. In January, the ASMI Injuries in Baseball Course will include an “ABBS Challenge” with a panel of ABBS members analyzing and discussing the biomechanics of sample baseball pitchers. In February, ABBS will host a baseball biomechanics session as part of the mid-year symposium for the International Society of Biomechanics in Sports. In March, ABBS will host a panel on baseball biomechanics in Major League Baseball at the SABR Analytics Conference. More courses and events will follow during the year for ABBS, alone and with other organizations. In addition, ABBS social media and career board should strengthen the bonds within our community.

So as you can see, it’s been a remarkable first year for ABBS. Biomechanics is becoming more and more vital for baseball players and organizations to maximize performance and minimize the risk of injury, and we look forward to working with you to improve our great game.

Glenn Fleisig, Ph.D.

Role of Lumbo-pelvic Control in Pitching

By: Hillary Plummer, PhD, ATC

It is no secret that elbow injuries have become exceedingly prevalent in baseball pitchers. Specifically, ulnar collateral ligament (UCL) tears continue to increase. UCL injuries that require reconstruction result in significant time-loss from baseball participation and rates of return to competition range from 68% to 94%.1-6 Despite increased awareness in injury prevention and load management measures for pitchers, injury rates do not appear to be decreasing.

Altered lumbo-pelvic control may be a contributing factor to upper extremity injuries. Pitching is a dynamic movement that requires coordinated sequencing of the kinetic chain. Optimal sequencing in which force is generated by the legs during the wind-up and transferred to the trunk, upper extremity to maximize ball velocity. Altered force transfer up the kinetic chain can result in compensations at the shoulder and elbow to make up for any lost force and may contribute to injury.7-10 Chaudhari et al11 examined the role of lumbo-pelvic control during a single-leg raise task on injury in MiLB pitchers. Anterior-posterior deviation of the pelvis was measured using a Level Belt. Pitchers rated as having poor lumbo-pelvic control had a high likelihood of missing more than 30 days during the season (p = 0.023). Anterior-posterior deviation scores were also divided into tertials and pitchers in the highest tertial were 3 times more likely to miss at least 30 days than those in the lowest tertial. It is possible that pitching biomechanics contributed to injury in their sample of pitchers. Recent work by Laudner and colleagues12 examined lumbo-pelvic control during a single-leg balance test and shoulder and elbow kinetics during pitching. No significant relationships with the stride leg lumbo-pelvic control and kinetics were observed. A relationship between lumbo-pelvic control on the drive leg and maximum shoulder abduction torque (r= 0.44, p= .003) and elbow varus torque (r= 0.46, p= .002) were observed. Over time, greater shoulder and elbow kinetics may contribute to injury.

There is also evidence to suggest that lumbo-pelvic control is related to pitching performance. Chaudhari et al13 used the same single-leg raise task to assess the role of lumbo-pelvic control on pitching performance. Pitchers with better lumbo-pelvic control (score of <7° of lumbo-pelvic movement) had lower walks plus hits per inning pitched (1.4 ±  0.3 vs. 1.6 ±  0.36, ES = 0.79, p = 0.013) and a greater number of innings pitched during the season (78.9 ± 38.7 vs. 53.4 ±  42.5, ES = 0.64, p = 0.043) compared to pitchers poor lumbo-pelvic control.

These studies highlight the role of lumbo-pelvic control on injury and performance in baseball pitchers. Prospective studies examining lumbo-pelvic control and pitching biomechanics and injury throughout a season are needed. Clinicians who work with pitchers should monitor and target any deficits in lumbo-pelvic control in pitchers to improve performance and reduce injury.

1. Thompson WH, Jobe FW, Yocum LA, Pink MM. Ulnar collateral ligament reconstruction in athletes: Muscle-splitting approach with transposition of the ulnar nerve. J Shoulder Elbow Surg. 2001;10(2):152-157.

2. Dodson CC, Thomas A, Dines JS, Nho SJ, Williams RJ, Altchek DW. Medial ulnar collateral ligament reconstruction of the elbow in throwing athletes. Am J Sports Med. 2006;34(12):1926-1932.

3. Rohrbough JT, Altchek DW, Hyman J, Williams RJ, Botts JD. Medial collateral ligament reconstruction of the elbow using the Docking Technique. Am J Sports Med. 2002;30(4):541-548.

4. Dines JS, ElAttrache NS, Conway JE, Smith W, Ahmad CS. Clinical outcomes of the DANE TJ Technique to treat ulnar collateral ligament insufficiency of the elbow. Am J Sports Med. 2007;35(12):2039-2044.

5. Paletta GA, Wright RW. The modified docking procedure for elbow ulnar collateral ligament reconstruction: 2-year follow-up in elite throwers. Am J Sports Med. 2006;34(10):1594-1598.

6. Erickson BJ, Bach BR, Jr., Cohen MS, et al. Ulnar Collateral Ligament Reconstruction: The Rush Experience. Orthop J Sports Med. 2016;4(1):2325967115626876.

7. Chu SK, Jayabalan P, Kibler WB, Press J. The kinetic chain revisited: New concepts on throwing mechanics and injury. Physical Medicine and Rehabilitation. 2016;8(35):S69-77.

8. Davis JT, Limpisvasti O, Fluhme D, et al. The effect of pitching biomechanics on the upper extremity in youth and adolescent baseball pitchers. Am J Sports Med. 2009;37(8):1484-1491.

9. Kibler WB, Chandler JB, Shapiro R, Conuel M. Muscle activation in coupled scapulohumeral motions in the high performance tennis serve. Br J Sports Med. 2007;41:745-749.

10. Lintner D, Noonan TJ, Kibler WB. Injury patterns and biomechanics of the athlete’s shoulder. Clin Sports Med. 2008;27(4):527-551.

11. Chaudhari AM, McKenzie CS, Pan X, Onate JA. Lumbopelvic control and days missed because of injury in professional baseball pitchers. Am J Sports Med. 2014;42(11):2734-2740.

12. Laudner KG, Wong R, Meister K. The influence of lumbopelvic control on shoulder and elbow kinetics in elite baseball pitchers. J Shoulder Elbow Surg. 2019;28(2):330-334.

13. Chaudhari AM, McKenzie CS, Borchers JR, Best TM. Lumbopelvic control and pitching performance of professional baseball pitchers. J Strength Cond Res. 2011;25(8):2127-2131.