Several studies show that the dominant arm in baseball throwers have increased external rotation and decreased internal rotation compared with their non-dominant arm. (4,5) This loss of internal rotation on the throwing arm compared to non-throwing arm is defined as GIRD, or glenohumeral internal rotation deficit.
For measurements of glenohumeral internal rotation, the athlete is placed in the supine position with the humerus abducted to 90 degrees. A towel roll was placed under the distal aspect of the humerus maintaining the humerus parallel to floor. The elbow is flexed to 90 degrees and the humerus is internally rotated until the coracoid begins to move. The measurements are made using a goniometer with a bubble level indicator. Please consult with a qualified medical professional in order to obtain results from this objective test (Figure 1).
There is a big debate in the sports medicine field regarding GIRD and it being caused by capsular, muscular, and osseous (bony adaptation) or a combination of all three adaptations. Due to these stresses placed on the shoulder during the throwing motion, previous studies have revealed that adaptive changes occur within the humerus know as humeral retroversion. This allows for greater shoulder external rotation and less internal rotation as compared to the non-throwing shoulder. (8)
We, as athletic trainers/physical therapists, can affect motion if caused by either capsular or muscular tightness. Some believe that a posterior inferior capsular contracture.gunnertechnetwork.comelops due to repetitive distraction causing micro-trauma in tension during the follow-through phase of throwing. This occurs due to Wolf’s law, the SAID principle, as glenohumeral distraction force is equal to or greater than the pitcher’s body weight. (6) Others believe that due to the high eccentric activity of the posterior cuff during the follow-through phase of throwing, this may cause a rise in muscular tension and an associated loss of internal rotation range of motion. (7) Competitive overhead throwing athletes perform at the extremes of glenohumeral motion and place tremendous repetitive stresses on the shoulder.
Regardless of what causes this deficit, this contracture produces altered glenohumeral kinematics that may lead to injury. There is also debate on how the humeral head is altered due to GIRD. One theory, due to the posterior shoulder tightness, the humeral head translates anteriorly during end range cocking phase applying stress to the posterior rotator cuff. This may also place increased stress on the anterior capsule causing symptomatic anterior instability. In contrast, others believe the posterior capsular contracture with decreased internal rotation does not allow the humeral head to rotate externally into its normal postero-inferior position in the late cocking phase of throwing. The decreased internal rotation caused by this posterior capsular contracture causes a posterior superior obligate migration of the humeral head in maximum external rotation. The posterior superior shift causes the SLAP lesion via the peel back mechanism. This may predispose the thrower to an internal impingement type injury. Continued internal impingement leads to deepening of the tear and extension of delamination. Further microtrauma, or continued throwing, may produce a full thickness rotator cuff tear. (1)
What we, the San Francisco Giants Medical Staff are doing are measuring all athletes at the beginning of spring training as well as the end of the season. If athletes have a GIRD of 20 degrees or more (Figure 2), we mandate them receiving hands-on stretching at the beginning and the end of each day. If an athlete has a GIRD of 18-20 degrees, we have them perform the sleeper stretch regularly and then re-measure in 3 weeks time. If their GIRD is less than 18 degrees (Figure 3), they are no longer required to stretch regularly, just perform the self sleeper stretch. Over the past 2 years, our organization has decreased our shoulder surgeries by 76% by implementing a more regimented, required stretching program.
We have noticed that new draftees signing with the Giants organization, from either college or high school, have increased GIRD measurements. A regimented stretching program for baseball players with greater than 18 degrees of GIRD to be stretched prior to throwing as well as after throwing at the collegiate and high school level may prove to decrease career ending injuries to the shoulder. It is our goal to not allow an athlete to throw until his GIRD measurement is less than 18 degrees.
A recent study published in the American Journal of Sports Medicine, notes that GIRD maybe associated with elbow valgus instability as well. That being said, an internal rotation stretching program at the high school and collegiate levels may also assist in preventing the epidemic of ulnar collateral ligament injuries. Their has been a big push by sports medicine specialists limiting pitch counts, not allowing curve balls to be thrown at the little league level, etc. I would like to see a shoulder internal rotation stretching program at every high school and college training room in order to allow our young athletes to stay healthy and dream big. O
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Please email Ben Potenziano with any questions at firstname.lastname@example.org.
- Lintner, David, Mayol, Magdiel, Uzodinma, Obinna, Jones, Rex, and Labossiere, David. Glenohumeral Internal Rotation Deficits in Profressional Pitchers Enrolled in an Internal Rotation Stretching Program. The American Journal of Sports Medicine. 2007; volume 35, No. 4: 617-621.
- Dines, Joshua S., Frank, Joshua B., Akerman, Meredith, and Yocum, Lewis A. Glenohumeral Internal Rotation Deficits in Baseball Players with Ulnar Collateral Ligament Insufficiency. The American Journal of Sports Medicine. 2009; Volume 37, No. 3: 566-570.
- Reinold, MM, Wilk, KE, Macrina, LC, et al. Changes in Shoulder and Elbow Passive Range of Motion After Pitching in Profressional Baseball Players. The American Journal of Sports Medicine. 2008; Volume 36: 523-527.
- Crocket, HC, Gross, LB, Wilk, KE, et al. Osseous Adaptation and Range of Motion at the Glenohumeral Joint in Profressional Baseball Pitchers. The American Journal of Sports Medicine. 2002; Volume 30: 20-26
- Reagan, KM, Meister, K, Horodyski, MB, Werner, DW, Carruthers, C, Wilk, K. Humeral Retroversion and its Relationship to Glenohumeral Rotation in the Shoulder of College Baseball Players. The American Journal of Sports Medicine. 2002; Volume 30: 354-360.
- Morgan, Craig. Presentation at ASMI Injuries in Baseball course 2003.
- Reinold, MM, Wilk, KE, Macrina, LC, Sheheane, C, Shouchen, D, Flesig, GS, Crenshaw, K and Andrews, JR. Changes in Shoulder and Elbow Passive Rom of Motion After Pitching in Profressional Baseball Players. The American Journal of Sports Medicine. 2008. Volume: 36; 523-527.
- Crockett, HC, Gross, LB, Wilk, KE, Schwartz, ML, Reed, J, O’Mara, J, Reilly, MT, Dugas, JR, Meister, K, Lyman, S, and Andrews, JR. Osseous Adaptation and Range of Motion at the Glenohumeral Joint in Profressional Baseball Pitchers. The American Journal of Sports Medicine. 2002. Volume: 30; 20-26.
What to do with GIRD information?
The previous overview provides coaches, players and athletic trainers with more information on how they can assist their players. The coaches should assist their players with an intervention plan of sleeper stretches as well hands on stretching if an Athletic Trainer is available.
The San Francisco Giants stretch all their players that are red flagged. These players are stretched by the Athletic Trainer or Physical Therapist on staff. Those players that have been noted as being tight are taught how to perform the sleeper stretches on their own. We advise them to stretch prior to stretching and after their session. The sleep stretch in our opinion is a valuable component of our overall shoulder program. We have seen a decrease in shoulder injuries since implementing the program throughout the system. The Giants medical staff believes this is an important part of a throwing program for a high school athlete to a professional baseball player.
There are several stretches that we perform and the Internal Rotation Sleeper Stretch will be the first that is shown. The athlete performs this stretch while he/she are lying on their dominant throwing side. Let’s assume this player is right handed. They would lay on their right side with their arm at 90 degree with their body over their shoulder. They would push their wrist downward. Be sure to hold the stretch for a minimum of 20 seconds and a minimum of 5 times/day. The athlete should feel the stretch in the posterior shoulder. I have included the photos so you can see exactly how these stretches are performed.
The other stretches that have been added are the Pectorals Minor and Major stretch. We also include an elbow stretch which you will see in the final two pictures. They are Elbow Extension stretch which can be done with a bat and a dumbbell. The dumbbell stretch should be done with a towel under the elbow. The dumbbell should not weigh more than 5-10 lbs.
The San Francisco Giants Medical Staff has been applying these stretching methods throughout our system and have seen significant gains.
We recommend an Athletic Trainer or Physical Therapist perform these stretches.
If you were told you have tight internal rotation of your shoulder, perform the following stretches and follow-up with us for new measurements in 2 weeks to track your progress. If you have any questions regarding proper form, please ask a trainer to assist.
Internal Rotation Sleeper Stretch In side lying position with arm up in range of 75 -110 degrees with elbow bent to 90 degrees with body leaning over shoulder, push wrist down with opposite hand. Hold stretch for 20 seconds and perform minimum of 5 times/day. (Especially important to perform before and after each throwing session)
Pectoralis Minor stretch Place half foam roll on table, line up foam roll with spine and lay on top allowing your shoulders to wrap around roll. Lay there for 5-10 minutes every day.
Pectoralis Major Stretch Stand in doorway and place front of shoulder and inside of bent arm on surface of wall. Position bent elbow around the same height of shoulder, lean into wall allowing shoulder to be pushed back. Hold stretch for 20 seconds and perform minimum of 3 times/day
If you were told you have limited elbow extension, perform the following stretches and follow-up with us for new measurements in 2 weeks to track your progress. If you have any questions regarding proper form, please ask a trainer to assist.
Elbow Extension Stretch In sitting position with towel roll just above elbow joint, grasp end of bat and push into elbow extension with other hand holding opposite end of bat. A variation of this stretch would be to hold a 5-10 lbs weight and allow to extend elbow. Hold stretch for 20 seconds and perform minimum of 3 times/day.
Ben Potenziano, M.Ed, ATC, CES Strength and Conditioning Coach
Ben Potenziano has been with the San Francisco Giants for 6 seasons. This is his fifth as the team’s strength and conditioning coach. Currently in his second stint with the Giants organization, he had spent five seasons overall in the club’s minor league system. He has previously served as head athletic trainer in the San Francisco system at short-season, single-A, double-A and the club’s affiliate in the Arizona Rookie League. He is a member of the Professional Baseball Athletic Trainers Society and National Strength and Conditioning Association and the National Athletic Trainers Association. Ben is a graduate of the University of Maine at Farmington with a bachelor’s degree in Community Health Education and a Masters of Physical Education with a concentration in Exercise Science from the University of Maine at Orono.
Article provided by Performance Conditioning Baseball/Softball www.performancecondition.com/baseballsoftball the Official Publication of the Professional Baseball Strength and Conditioning Coaches Society