Effectiveness of Manual Therapy and Stretching for Baseball Players With Shoulder Range of Motion Deficits

Abstract

Background: Baseball players displaying deficits in shoulder range of motion (ROM) are at increased risk of arm injury. Currently, there is a lack of consensus regarding the best available treatment options to restore shoulder ROM.

Hypothesis: Instrumented manual therapy with self-stretching will result in clinically significant deficit reductions when compared with self-stretching alone.

Study design: Controlled laboratory study.

Methods: Shoulder ROM and humeral torsion were assessed in 60 active baseball players (mean age, 19 ± 2 years) with ROM deficits (nondominant - dominant, ≥15°). Athletes were randomly assigned to receive a single treatment of instrumented manual therapy plus self-stretching (n = 30) or self-stretching only (n = 30). Deficits in internal rotation, horizontal adduction, and total arc of motion were compared between groups immediately before and after a single treatment session. Treatment effectiveness was determined by mean comparison data, and a number-needed-to-treat (NNT) analysis was used for assessing the presence of ROM risk factors.

Results: Prior to intervention, players displayed significant ( P < 0.001) dominant-sided deficits in internal rotation (-26°), total arc of motion (-18°), and horizontal adduction (-17°). After the intervention, both groups displayed significant improvements in ROM, with the instrumented manual therapy plus self-stretching group displaying greater increases in internal rotation (+5°, P = 0.010), total arc of motion (+6°, P = 0.010), and horizontal adduction (+7°, P = 0.004) compared with self-stretching alone. For horizontal adduction deficits, the added use of instrumented manual therapy with self-stretching decreased the NNT to 2.2 (95% CI, 2.1-2.4; P = 0.010).

Conclusion: Instrumented manual therapy with self-stretching significantly reduces ROM risk factors in baseball players with motion deficits when compared with stretching alone.

Clinical relevance: The added benefits of manual therapy may help to reduce ROM deficits in clinical scenarios where stretching alone is ineffective.

Keywords: baseball; glenohumeral internal rotation deficit (GIRD); instrumented manual therapy; posterior shoulder tightness (PST).

Figure 1.

Study design. Two hundred seventy-six patients were screened for study eligibility, and shoulder range of motion was measured immediately pre- and postintervention. The “ISTM & Stretch” group received 4 minutes of instrumented manual therapy plus 4 minutes of supervised posterior shoulder stretching; the “Stretching Only” group performed 4 minutes of supervised posterior shoulder stretching. ISTM, instrument-assisted soft tissue mobilization; PST, posterior shoulder tightness.

Figure 2.

Humeral torsion. Humeral torsion was assessed by a sonographer who rotated the participant’s, humerus until the apices of the tuberosities were oriented parallel to the plinth under ultrasound imaging. Once aligned, a second examiner recorded the relative rotation angle via a digital inclinometer.

Figure 3.

Supervised self-stretching. Athletes were supervised during the standardized performance of 2 stretches, which were both held for 1 minute each. Both stretches were performed with the athlete in a side-lying position and the shoulder elevated to 90° of flexion. (a) The sleeper stretch was performed by internally rotating the shoulder until a gentle stretch was felt in the posterior shoulder. (b) The cross-body adduction stretch was performed by pulling the throwing arm toward the ceiling until a gentle stretch was felt in the posterior shoulder.

Figure 4.

Posttest range of motion deficits. ISTM, instrument-assisted soft tissue mobilization; ROM, range of motion.*Indicates significant differences between treatment groups.