Research Review #1: Instrumented-Assisted Soft Tissue Mobilization for Baseball Players with Loss of Shoulder Motion

Bailey LB, Thigpen CA, Hawkins RJ, Beattie PF, Shanley E. Effectiveness of manual therapy and stretching for baseball players with shoulder range of motion deficits. Sports Health: A Multidisciplinary Approach. 2017;9(3):230-237. doi:10.1177/1941738117702835.


Baseball players with shoulder range of motion (ROM) deficits are up to 6 times more likely to sustain an injury1, 2.  Structural osseous adaptations and soft tissue impairments have been implicated as sources for these ROM deficits into both internal rotation (IR) and horizontal adduction.  The purpose of this particular study was to compare self-stretching exercise targeting shoulder ROM deficits to instrument-assisted manual therapy and self-stretching in baseball players.

Study Population

  • Inclusion criteria:
    • Males 15 years or older (n=60)
    • Pitcher or position player on an organized baseball team
    • 15-degree loss of total arc of rotation motion compared to non-throwing shoulder (with at least a 15-degree deficit in IR) and/or a 15-degree deficit in horizontal adduction.
  • Exclusion criteria
    • Shoulder pain within the last 3 months
    • Previous shoulder surgery
    • Not actively participating in organized baseball
    • >30% disability on Penn Shoulder Score or the Functional Arm Scale for Throwers.

Dependent Variables

  • ROM measurements were assessed immediately before and after the intervention session. Assessors were blinded to treatment group.
    • Shoulder IR, ER and total arc of motion Assessment:
    • Shoulder Horizontal Adduction Assessment

Independent Variables

  1. Self-Stretching Group: The sleeper stretch and side-lying cross-body adduction stretch were performed for two repetitions of one minute each.
  2. Self-Stretching plus Instrumented Manual Therapy: The same two stretches were followed by instrument-assisted soft tissue mobilization in the prone position targeting the infraspinatus and teres minor for two minutes each.

Key Results

  • Participants in the instrument-assisted group achieved significantly greater improvements in IR (12.1 vs. 7.2 degrees), total arc of motion (14.0 vs. 8.4 degrees), and horizontal adduction (13.5 vs. 6.9 degrees) compared to the stretching only group.
  • Neither group showed significant changes in ER ROM.

Study Limitations

  • Research participants were asymptomatic baseball players
  • Outcomes were assessed only immediately following a brief 10-minute intervention with no long-term follow-up
  • The instrument-assisted group received a disproportionate amount of treatment time compared to the stretching only group

Practical Implications & Additional Thoughts

This study supports the role of instrument-assisted soft tissue mobilization plus stetching to the posterior shoulder for achieving immediate within-session improvements in shoulder ROM in baseball players.  Shoulder ROM deficits have been shown to be risk factors for injury in baseball players.  The players included in this study were asymptomatic but did present with these injury risk factors.

It is important to keep in mind that all participants in this study presented with deficits in total arc of motion compared to their non-throwing side.  Applying these findings to players without deficits in total arc of motion may be inappropriate based on the concept that these changes are the result of osseous, not soft tissue, adaptations.  A detailed assessment of the athlete’s ROM profile is important before prescribing any manual therapy or self-stretching program for overhead athletes.

Deficits in shoulder ER and flexion have also been associated with shoulder and elbow injury in baseball players3, 4.  Therefore clinical decisions for baseball players should be based on a detailed assessment of the following shoulder motions: ER, IR, total arc of motion, flexion, and horizontal adduction.  Players without total arc of motion deficits but with side-to-side asymmetries in IR will likely not require a comprehensive stretching or manual therapy intervention.  However, a player presenting with a 20-degree side-to-side asymmetry in total arc of motion will likely benefit from an individualized manual therapy and self-stretching program.

Instrument-assisted soft tissue mobilization was used as an intervention in this study.  However, it is my experience that the same level of immediate improvement can be achieved by using proprioceptive neuromuscular facilitation techniques directed to the shoulder or thrust manipulation to the thoracic spine.   The specific manual therapy intervention is likely not all that important.  Use what you and your athlete are comfortable with, reassess, and then move on to the rest of your program whichshould include a solid foundation of resistance exercise.


  1. Shanley E, Rauh MJ, Michener LA, Ellenbecker TS. Incidence of injuries in high school softball and baseball players. J Athl Train. 2011;46(6):648-654.
  2. Wilk KE, Macrina LC, Fleisig GS, et al. Correlation of glenohumeral internal rotation deficit and total rotational motion to shoulder injuries in professional baseball pitchers. Am J Sports Med. 2011;39(2):329-335. doi:10.1177/0363546510384223.
  3. Wilk KE, Macrina LC, Fleisig GS, et al. Deficits in glenohumeral passive range of motion increase risk of shoulder injury in professional baseball pitchers. Am J Sports Med. 2015;43(10):2379-2385. doi:10.1177/0363546515594380.
  4. Wilk KE, Macrina LC, Fleisig GS, et al. Deficits in glenohumeral passive range of motion increase risk of elbow injury in professional baseball pitchers: A prospective study. Am J Sports Med. 2014;42(9):2075-2081. doi:10.1177/0363546514538391.

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