The effect of scapular protraction on isometric shoulder rotation strength in normal subjects

Jay Smith, Christopher T. Dietrich, Brian R. Kotajarvi, Kenton R. Kaufman

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

To measure the effect of scapular protraction on isometric shoulder rotation strength, 20 normal subjects completed 2 maximal isometric internal and external rotation contractions in 2 scapular positions (scapula neutral [SN] and scapula protracted [SP]) from 3 arm positions (90° internal rotation [IR], 45° internal rotation [MR], and 90° external rotation [ER]). Scapular protraction reduced shoulder rotation strength in 5 of 6 test positions (P < .0004), with significant interactions between scapular position and arm position (P < .001) and between scapular position and contraction type (P < .0001). Protraction significantly reduced IR strength by 13% to 24% relative to SN. The effect of SP on ER strength was more position-dependent, increasing strength by 6% in the IR position and decreasing it by 7% in the MR position and 20% in the ER position. In conclusion, acute changes in scapular position affect shoulder isometric IR and ER strength. The potential adverse effects of scapular protraction on shoulder rotation strength should be considered during the evaluation and treatment of shoulder pain.

Original languageEnglish (US)
Pages (from-to)339-343
Number of pages5
JournalJournal of Shoulder and Elbow Surgery
Volume15
Issue number3
DOIs
StatePublished - May 1 2006

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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