Shoulder-Abduction Angle and Trapezius Muscle Activity During Scapular-Retraction Exercise


KARA D., HARPUT G., DÜZGÜN İ.

JOURNAL OF ATHLETIC TRAINING, vol.56, no.12, pp.1327-1333, 2021 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 56 Issue: 12
  • Publication Date: 2021
  • Doi Number: 10.4085/1062-6050-0053.21
  • Journal Name: JOURNAL OF ATHLETIC TRAINING
  • Journal Indexes: Science Citation Index Expanded, Scopus, Academic Search Premier, BIOSIS, CINAHL, EBSCO Education Source, EMBASE, MEDLINE, SportDiscus
  • Page Numbers: pp.1327-1333
  • Keywords: electromyography, scapula, resistance train-ing, superficial back muscles, ELECTROMYOGRAPHIC ACTIVITY, ACROMIOHUMERAL DISTANCE, SERRATUS ANTERIOR, ACTIVATION, KINEMATICS, ELEVATION, REHABILITATION, STRENGTH, POSITION

Abstract

Context: Scapular-retraction exercises are often prescribed to enhance scapular stabilization. and UT/LT ratios during scapular-retraction exercises with elastic resistance at different shoulder-abduction angles. Patients or Other Participants: Thirty-five asymptomatic individuals. was used to evaluate UT, MT, and LT activities during the scapular-retraction exercise at 0 degrees, 45 degrees, 90 degrees, and 120 degrees of shoulder abduction. Results: The mean muscle activity ranged from 15.8% to 54.7% maximal voluntary isometric contraction (MVIC) for UT, 30.5% to 51.6% MVIC for MT, and 21.4% to 25.5% MVIC for LT. A significant muscle x angle interaction was found (P < .001). Post hoc analysis revealed that the MT was more activated than the UT and LT during both retraction at 0 degrees (P < .001 and P= .01, respectively) and 120 degrees (P = .03 and P = .002, respectively). During retraction at 45 degrees and 90 degrees, the LT generated less activity than the UT (P = .02 and P = .03, respectively) and MT (P < .001 and P = .002, respectively). Further, UT/MT and UT/LT ratios during retraction at 0 degrees were lower than at 45 degrees (P = .03 and P = .001, respectively) and 90 degrees (P < .001 and P < .001, respectively). Retraction at 90 degrees resulted in a higher UT/LT ratio than at 45 degrees (P = .004) and 120 degrees (P = .004). Conclusions: Due to less UT relative to MT activity, retraction at 0 degrees, 45 degrees, and 120 degrees can be preferable in early shoulder training or rehabilitation. Additionally, retraction at 90 degrees was the most effective exercise in activating all parts of the trapezius muscle.