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Prone Shoulder External Rotation From 90 Degrees of Abduction

The Prone Shoulder W

Ronai, Peter M.S., RCEP, CEP, CSCS-D, FACSM

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doi: 10.1249/FIT.0000000000000345
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Prone shoulder external rotation from 90 degrees of abduction, the prone shoulder W.


The prone shoulder W is part of a group of upper body exercises known as the T-Y-I-W series. As the name indicates, it is typically performed in a prone position and is intended to activate and strengthen posterior shoulder girdle muscles.


Supraspinatus, infraspinatus, teres minor, deltoid (middle and posterior fibers), trapezius (middle and lower fibers), rhomboids, and levator scapula (Figure 1).

Figure 1
Figure 1:
Muscles activated during the prone W.


The prone W exercise activates muscles that provide dynamic stability, optimal muscle length and tension, and proper positioning of the scapula and shoulder complex on the thorax during upper extremity activities (2,3,10–12). Unlike the previously discussed prone Y exercise (July/August 2016), the humerus or upper arm does not move above shoulder height. The prone shoulder W also is known as prone shoulder external rotation from 90 degrees of abduction (W) (2,10) and will be described in a subsequent section.


Exercises to promote shoulder girdle stability are integral components of strength and conditioning and rehabilitation and postrehabilitation exercise programs for persons who perform repetitive overhead motions during sports or occupational activities (2,3,8–12). Functional imbalances between the upper trapezius and the lower trapezius, middle trapezius, and the serratus anterior muscles have been associated with conditions like shoulder instability and subacromial impingement syndrome, which can cause shoulder pain and dysfunction (2–4,6–10). The prone W exercise has been shown to elicit high muscle electromyographic activity in primary stabilizers of the shoulder complex as well as favorable ratios of muscle activation between the upper and lower trapezius (UT:LT) and between the upper and middle trapezius (UT:MT) (2–4,6–10). The shorter lever arm created by flexing the elbow and the relatively lower angle of humeral elevation (abduction) distinguish it from the prone Y exercise and can be a good precursor to performing it.

As with the prone Y and prone T exercises, the prone W can be performed on either a matted floor, (treatment) plinth table, or a multipurpose training bench. Plinth tables typically enable clients to place their faces within a cutout hole that facilitates breathing and in-line stabilization of the cervical and thoracic (neck and upper back) spines. Videos of the prone W from a plinth can be viewed here and A small pillow placed under the top of the pelvis and hips can provide additional alignment and support to the lower back. Clients also can place their foreheads on a small hand-rolled towel and place a small pillow under their waist and hips to achieve similar alignment if they are lying prone on the floor. The use of the floor or a plinth table provides the shoulder girdle with additional extrinsic support and reduces the distance which the arms must be lifted from the starting position as compared with a multipurpose training bench (9,10). Exercise intensity can be increased by progressing from a supportive surface like the floor or treatment table to a multipurpose training bench where the arm is raised by performing a rowing motion first and lifted through a greater range of motion. A video of the prone W from a training bench can be viewed here Clients should exhale during the lifting phase and inhale during the lowering phase of each exercise. External loading should never prevent clients from performing each exercise in a controlled manner.

This article is not meant to help readers diagnose or treat shoulder pain or injuries. Clients should be free of shoulder or upper extremity injuries and related pain before performing these exercises. The onset of injury-related pain warrants termination of exercise and immediate client consultation with a physician, physical therapist, or other health care provider.



Clients lie prone and maintain a straight line position between their head, neck, and spine with their elbows flexed 90 degrees and with their upper arms (humerus) resting on either the floor or plinth table in approximately 90 degrees of abduction. The arms hang down perpendicularly with the floor if the exercise is performed on a multipurpose training bench and must be elevated against gravity in a rowing motion by retraction and horizontal abduction of the scapula and glenohumeral (shoulder) joint, respectively, to begin the exercise (2–4,10) (the starting and ending phase positions appear in Figures 2A, B).

Figure 2
Figure 2:
A. Prone W exercise starting and finishing positions from a plinth table upward phase position. B. Prone W exercise starting and finishing position from a training bench.Photos courtesy of Peter Ronai.


By concentric actions of the lower trapezius, rhomboids, infraspinatus, and teres minor, the scapulae are retracted and posteriorly tilted and the upper arms (humerus) are externally rotated until they are almost parallel with the floor. The scapula and arms are held in this position for a count of three. Clients are prompted not to raise either their elbows, arms, or forearms behind their torsos. This position can increase stresses on the anterior shoulder joint (6,7,9,10) (the upward phase position appears in Figures 3A–D and Figures 4A, B).

Figure 3
Figure 3:
A. Prone W exercise first part of upward phase from a plinth table. B. Prone W exercise second part of upward phase from a plinth table. C. Prone W exercise first part of upward phase from a training bench. D. Prone W exercise second part of upward phase from a training bench.Photos courtesy of Peter Ronai.
Figure 4
Figure 4:
A and B. The upward phase from a training bench.Photos courtesy of Peter Ronai.


The arms and scapulae return to the starting position in a controlled manner by eccentric actions of the trapezius, rhomboids, infraspinatus, and teres minor (2–4,8–10).

Exercise load and intensity selection can be based on the individual goals of each client (10). Although lighter loads and higher repetitions have typically been recommended for scapulohumeral stability exercises, results from a few studies suggest that it might not be necessary to limit the amount of weight used with these exercises if performed by healthy individuals without a history of shoulder pathology (1,5,10).


The prone shoulder W exercise is part of the (T-Y-I-W) series intended to improve scapulothoracic and glenohumeral joint muscle function and shoulder complex stability. Exercises can be performed without external loading in clients who are either unaccustomed to doing them or are deconditioned. External resistance can be added in the form of dumbbells or cuff weights as tolerated by clients and as their strength and endurance improve.


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Recommended Reading:

  • Ekstrom RA, Donatelli RA, Soderberg GL. Surface electromyographic analysis of exercises for the trapezius and serratus anterior muscles. J Orthop Sports Phys Ther. 2003;33(5):247–58.
  • McCabe RA, Orishimo KF, McHugh MP, Nicholas SJ. Surface electromyographical analysis of the lower trapezius muscle during exercises performed below ninety degrees of shoulder elevation in healthy subjects. NAJSPT. 2007;2(1):34–43.

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