Shoulder Flexion Deficits May Lead to Elbow Injuries in Baseball Pitchers

It’s no secret that elbow injuries are a big problem in baseball. A study released in 2017 used injury data to examine 750 Major League Baseball (MLB) and 7500 Minor League Baseball (MiLB) players over the course of four seasons (2). This data showed that elbow injuries were the 4th most prevalent type of injury at both the MLB and MiLB level. Although they are the 4th most prevalent type of injury, they account for the highest number of days missed (2-5). In fact, Conte and colleagues found that 22% of days spent on the injured list are the result of an elbow injury (3).


The most common of these injuries are to the medial elbow, specifically the ulnar collateral ligament (UCL), flexor-pronator mass, ulnar nerve, and posteromedial fossa. Of particular importance are UCL injuries, as a UCL surgery can result in a significant number of games missed. Although UCL surgeries are on the decline in MLB players, they continue to rise dramatically at the youth, collegiate, and MiLB level (4). There are several factors that can contribute to a medial elbow injury in baseball players, such as a hip internal rotation deficit (learn more here) or inadequate support from the flexor-pronator mass (learn more here). Another factor that deserves attention is a shoulder flexion deficit.


Correlation Between Shoulder Flexion Deficits and Elbow Injuries


Dr. Christopher Camp and colleagues published a study in 2017 as well that was able to demonstrate how a lack of shoulder mobility could actually lead to an increased risk of elbow injury in professional baseball players (1). Prior to each season, the training staff for a professional baseball team would perform a comprehensive physical examination on each of their pitchers. Range of motion measurements consisted of supine shoulder flexion, horizontal adduction, external rotation, and internal rotation as well as elbow flexion and extension (all measurements were taken passively). Player demographics were also recorded, including age, height, weight, and body mass index. Pitchers were then prospectively followed over the course of the season and injuries were catalogued. During the study period, from 2010 to 2015, a total of 28 elbow injuries were recorded for pitchers in the organization (1). This accounted for about 21% of all pitcher injuries during this time. Of all the variables recorded prior to the season, a shoulder flexion deficit was found to be the greatest predictor of elbow injury.

A shoulder flexion deficit is defined as a flexion deficit of more than 5 degrees in the throwing arm when compared to the non-throwing arm (1,6). This means if we are examining a right-handed pitcher who possesses 180 degrees of left shoulder flexion, we want to see at least 175 degrees of right shoulder flexion. If the right shoulder flexion was less that 175 degrees, this study found that the risk of sustaining an elbow injury increased by 2.83 times (1). In addition, the risk of elbow injury increased by 9% for each additional degree of decreased shoulder flexion.



Kevin Wilk and colleagues had similar findings in a previous study (6). They too performed a preseason physical examination and collected injury data from 2005 to 2012. During this time 49 elbow injuries occurred, and once again, shoulder flexion was found to be an important predictor. In this study, 25% of players with shoulder flexion deficits suffered an elbow injury, which was found to be a statistically significant relationship since only 11% of players without shoulder flexion deficits suffered an elbow injury (6). What’s interesting is they also came to the same conclusion that pitchers with shoulder flexion deficits were 2.8 times more likely to be placed on the injured list for an elbow injury.


Implications


These statistics are a bit alarming, as elbow injuries to pitchers can have a significant impact on, not only the player, but also the team. As mentioned earlier, numerous studies have reported that elbow injuries account for the highest number of days missed in professional baseball (2-5). Ciccotti et al. found that pitchers who were treated non-surgically missed an average of 33.2 days (2). This study, however, did not include season ending injuries because of the difficulty in quantifying days missed. In their study, 24.1% of elbow injuries involved the ulnar collateral ligament (UCL), 40.8% of which required season ending surgeries (2). This means that the 33.2 average days missed may actually be a gross underestimate of the actual time missed after sustaining an elbow injury in baseball.


UCL surgeries require the longest recovery out of all baseball injuries. It takes an average of 12-16 months for an MLB pitcher to return to their previous level of performance after UCL reconstruction (4). If the player’s injury only requires a UCL repair, the average recovery decreases to 6-9 months. Camp et al. included season ending injuries in their study and found that elbow injuries resulted in an average of 184 days missed (1). This number increased to 332.8 days missed when the injury was to the UCL.


Regional Interdependence


In physical therapy school, we are advised to not only look at the joint that is symptomatic, but to also look at the joints above and below because they may be contributing to the primary complaint. This is a concept known as regional interdependence and was brilliantly illustrated in a blog written by Mike Boyle in 2007 (click here). In short, stiffness at one joint can create accessory motion at an adjacent joint. Shoulder flexion deficits leading to elbow injuries in professional baseball players is an example of this occurring in real life. In this example, the elbow is the victim and the shoulder is the culprit. If we would have only focused our attention on the elbow, we may have missed this finding.

One theory for limited shoulder flexion leading to elbow injuries is that the elbow may be experiencing increased workloads and forces and, in turn, increased injury risk in an attempt to overcome deficiencies at the shoulder (1). This theory lends support to the concept of kinetic linking, where force and energy are transferred from our more proximal muscles to the more distal segments. Restrictions in range of motion cause energy leaks and compensations that may expose other segments to undo stress. Another baseball example of this occurring is hip internal rotation deficits leading to low back and abdominal injuries (4) as well as elbow injuries (click here).


Restoring Range of Motion


A common culprit to limitations in shoulder flexion in baseball pitchers is the latissimus dorsi, or lat muscle. The primary job of the lat is to extend and internally rotate the shoulder, the same motion that occurs during the action of throwing a baseball. Because of the size and strength of the lat muscle, elite level pitchers rely heavily on this muscle to generate power. The repetitive utilization of the lat can lead to a functional shortening of the muscle if enough attention is not paid to maintaining its extensibility. This shortening can lead to a decrease in shoulder flexion and external rotation. Interestingly, a deficit in external rotation at the shoulder was found to be the second greatest predictor of elbow injury in Dr. Christopher Camp’s study referenced previously (1).


To restore the extensibility to the lat muscle, we will follow a simple formula that consists of soft tissue, mobility, and motor control. One soft tissue option for addressing lat extensibility is foam rolling. Start by lying on your side with a foam roller resting just behind your arm pit. Lift your hips up and slowly roll from your arm pit to about 6 inches below. Repeat this motion for about 8-10 repetitions. If you find a tender spot, pause on that spot for about 10 seconds before performing 8-10 arm raises, as detailed in the video below, to pin the lat muscle down and take it through a gentle stretch. This exercise serves to decrease tissue tone so the lat is more willing to lengthen when we move to our next step, mobility drills.



Now that we have decreased tissue tone, we will try to lengthen the lat muscle by performing mobility drills. There are a couple options I really like for achieving this. The first one is the single arm foam roller lat stretch. Start in a quadruped position with a foam roller angled in front of one hand. With your palm facing up, reach across your body with the opposite arm, using the foam roller for assistance. Exhale at end range before returning to the starting position. Repeat 8 times.



Another great option, which I first learned from the staff at Cressey Sports Performance, is the T-spine bench mobilization. Start by kneeling with your elbows resting on an elevated surface and hands holding a dowel with your palms facing you. Next, sink your butt towards your heels, take your chest towards the ground, and curl your hands behind your head. Exhale and return to the starting position. This is also a great exercise for improving thoracic extension and triceps mobility, both of which are important for achieving full shoulder flexion and external rotation. Repeat 8 times.



Once we have increased the length of the lat muscle, we need to teach our body how to control this newly acquired range of motion. This is a concept known as motor control. There are a ton of options for this, but I find myself continuing to come back to a few in particular; the first of which is a wall slide with a lift off. Start by standing in a split stance with your pinkies resting on the wall in front of you. Slide your hands up the wall, lift off, and hold for 5 seconds. Return your hands to the wall then return to the starting position. Repeat 5 times.



Another one of my favorite options is the half kneeling KB windmill. Begin in a half kneeling position. Whichever foot is forward, the same arm will start with the kettle bell overhead. Sink your hips back towards your rear foot while reaching for the ground with the free hand. After palming the ground, return to the starting position. Repeat 8 times.



A third option is the waiter carry. Start by pressing a dumbbell or kettle bell overhead in one of your arms. While maintaining an upright posture, start walking. Not only is this a great exercise for overhead stability, it is also a great option for training core stability. I will typically program this exercise for one set of 30 seconds in each arm.



Other options for improving shoulder flexion include optimizing thoracic extension (click here) as well as scapular mechanics, which I will address in future blogs.


Summary


Preventing injuries is an inherently difficult task. As we continue to gain access to more data, we are able to begin to identify trends that can give us insights into markers that put an athlete at an increased risk for injury. In baseball, attempting to prevent elbow injuries has become a priority, as elbow injuries account for more games missed than any other injury in the sport (2-5). There are several factors to consider when attempting to protect the elbow joint, such as hip range of motion and flexor-pronator mass strength and tissue quality. Restrictions in shoulder flexion are also critically important. This is because a shoulder flexion deficit increases the risk of elbow injury by 2.8 times in baseball pitchers (1,6). Shoulder flexion is only one piece of the puzzle, but it is clearly an important one that deserves our attention. In order to give ourselves the best possible chance of mitigating the risk of injury, we must stop looking at the site of the injury for all the answers; we must continue to examine the athlete as a whole.



References:


1. Camp CL, Zajac JM, Pearson DB, Sinatro AM, Spiker AM, Werner BC, Altchek DW, Coleman SH, Dines JS. Decreased Shoulder External Rotation and Flexion Are Greater Predictors of Injury Than Internal Rotation Deficits: Analysis of 132 Pitcher-Seasons in Professional Baseball. Arthroscopy. 2017 Sep;33(9):1629-1636.

2. Ciccotti MG, Pollack KM, Ciccotti MC, D'Angelo J, Ahmad CS, Altchek D, Andrews J, Curriero FC. Elbow Injuries in Professional Baseball: Epidemiological Findings From the Major League Baseball Injury Surveillance System. Am J Sports Med. 2017 Aug;45(10):2319-2328.

3. Conte S, Requa RK, Garrick JG. Disability days in major league baseball. Am J Sports Med. 2001 Jul-Aug;29(4):431-6.

4. Cressey, E. (Host). (2020, October 22). Managing baseball injuries with Dr. Christopher Camp. (No. 77). [Audio podcast episode]. In Elite Baseball Development Podcast. Cressey Sports Performance. https://ericcressey.com/csp-elite-baseball-development-podcast-managing-baseball-injuries-with-dr-christopher-camp.

5. Posner M, Cameron KL, Wolf JM, Belmont PJ Jr, Owens BD. Epidemiology of Major League Baseball injuries. Am J Sports Med. 2011 Aug;39(8):1676-80.

6. Wilk KE, Macrina LC, Fleisig GS, Aune KT, Porterfield RA, Harker P, Evans TJ, Andrews JR. Deficits in glenohumeral passive range of motion increase risk of elbow injury in professional baseball pitchers: a prospective study. Am J Sports Med. 2014 Sep;42(9):2075-81.