Effect of Adduction During Glenohumeral External Rotation Exercises in the Scapulohumeral Muscles

Claudio Bascour-Sandoval; Rubén Gajardo-Burgos; Germán Gálvez-García; Mauricio Barramuño-Medina

Abstract

SUMMARY: The effect of adduction during glenohumeral external rotation (ER) exercises on the scapulohumeral muscles is controversial. The aim of this study was to evaluate the effect of carrying out adduction during external rotation exercises in low and high shoulder positions on the electromyographic (EMG) activity of the infraspinatus (IS), middle deltoid (MD), and posterior deltoid (PD) muscles. EMG activity of the IS, MD, and PD muscles of 20 healthy participants was evaluated. Subjects performed 6 ER exercises that combined two factors: i) different adduction pressures according to biofeedback unit (0, 5 and 10 mmHg), and ii) low and high shoulder position. The pressure was controlled using a biofeedback unit. The low and high shoulder positions were 20? and 90? of abduction. In the low shoulder position, the activity of the IS muscle increased as the pressure on the biofeedback unit increased and the MD and PD muscles presented the highest activity at 10 mmHg. In the high shoulder position, the activity of the IS muscle was higher at 0 and 10 mmHg, the MD muscle presented higher activity at 5 mmHg, and PD muscle activity did not vary with the pressure. The addition of adduction at a pressure of 5 mmHg in the low shoulder position promotes is activity. Likewise, adduction at a pressure of 10 mmHg will promote activity of the IS, MD, and PD.

Más información

Título según SCIELO: Effect of Adduction During Glenohumeral External Rotation Exercises in the Scapulohumeral Muscles
Título de la Revista: INTERNATIONAL JOURNAL OF MORPHOLOGY
Volumen: 39
Número: 5
Editorial: SOC CHILENA ANATOMIA
Fecha de publicación: 2021
Página de inicio: 1316
Página final: 1322
Idioma: en
DOI:

10.4067/S0717-95022021000501316

Notas: SCIELO