Scapular-focused exercise treatment protocol for shoulder impingement symptoms: Three-dimensional scapular kinematics analysis

Highlights

• Specific exercises for treatment of shoulder impingement syndrome are proposed.

• Protocol included neuromuscular and strengthening exercises applied for 8 weeks

• The exercises proposed in protocol change the kinematics of the scapulothoracic joint.

Abstract

Background

The present study aimed to describe the effects of a periscapular strengthening and neuromuscular training protocol in three-dimensional scapular kinematics and resting positioning in participants with shoulder impingement symptoms. Self-reported function was also evaluated.

Method

The study group comprised 50 subjects with shoulder impingement syndrome (control group, n = 25; treatment group, n = 25). The treatment group underwent 8 weeks of neuromuscular training and periscapular strengthening. Scapular kinematics was measured using an electromagnetic tracking device, and the Brazilian version of the Shoulder Pain and Disability Index (SPADI-Br) questionnaire was carried out before and after the treatment.

Findings

In the resting position, treated subjects had lower (p < 0.01) internal rotation of the scapula compared to the control group, with a large effect size (2.4). On the coronal plane, the treated group had less scapular upward rotation (p < 0.01) and less internal rotation (p < 0.05), with a medium effect size. On the sagittal plane, the treated group had less internal rotation (p < 0.01), less upward rotation (p < 0.05), and less scapular anterior tilt (p < 0.01), with a medium effect size. On the scapular plane, a reduction in upward rotation (p < 0.01) after the intervention was observed, with a large effect size. Moreover, a reduction in the total SPADI-Br score was found, with a mean difference of 32.4 [24.4; 40.4] points (p < 0.01) after the implementation of the protocol and a large effect size (2.0).

Interpretation

The results provide biomechanical support for the clinical rationale for indicating therapeutic exercises focused on the periscapular muscles to improve scapular dynamics.

Introduction

People with shoulder impingement syndrome (SIS) present differences in movements of the scapula when compared with asymptomatic individuals (Graichen et al., 2001, Hébert et al., 2002, Lawrence et al., 2014, Lin et al., 2005, Ludewig and Cook, 2000, Lukasiewicz et al., 1999, Warner et al., 1992), and these changes can contribute to impingement (Phadke et al., 2009, Schmitt and Snyder-Mackler, 1999). Patients with SIS report disability, especially during overhead movements, which may hinder activities of daily living and for some sports gestures (Moezy et al., 2014).

The presence of impact symptoms has been demonstrated by several electromyographic studies to initiate changes in periscapular muscle activity, such as an increase in upper trapezius muscle activity (Lin et al., 2011, Ludewig and Cook, 2000) and reduction in lower trapezius (Cools et al., 2007, Lin et al., 2011) and serratus anterior activity (Lin et al., 2011, Ludewig and Cook, 2000). Changes on the scapula movement can be observed via reducing the upward rotation in the frontal and scapular plane, between 30° and 60° of arm elevation (Lawrence et al., 2014), and reduction of the posterior tilt (Borstad and Ludewig, 2002, Endo et al., 2001, Lawrence et al., 2014) and reduction of external rotation in the arm elevation and lowering (Lopes et al., 2015) when compared with healthy subjects.

Evidence exists on the effectiveness of exercises designed to restore sensorimotor mechanisms in the shoulder to treat SIS through the use of feedback, because they promote coordinated activation of the muscles involved (Myers and Oyama, 2008, van Vliet and Heneghan, 2006). Therefore, the focus of treatment for the syndrome is on performing exercises, including stretching, strengthening, and neuromuscular control exercises (Dong et al., 2015, Escamilla et al., 2014, Ginn et al., 1997, Haik et al., 2016, Hanratty et al., 2012, Kromer et al., 2009).

Studies have assessed the effects of neuromuscular control and scapula-focused exercises on the scapular kinematics of individuals with shoulder impingement syndrome (Roy et al., 2009, Worsley et al., 2013). Worsley et al. (2013) examined the effect of scapular motor control training in a group of 16 individuals with shoulder impingement syndrome who underwent a 10-week treatment compared to a healthy control group. After treatment, the individuals from the SIS group had less pain, improved function, and increased posterior tilt of the scapula. However, in this study, manual therapy was included as part of the motor control program, and a small sample size was used, considering kinematic variables. Roy et al. (2009) assessed the effect of motor control training of only 8 subjects with SIS, and an improvement of function and pain and increase in posterior tilt of the scapula were found. However, this study did not assess the scapular muscle strength. Thus, evidence related to the effect of neuromuscular control and scapula-focused exercises on the scapula kinematics is limited.

A recent systematic review of clinical trials validated a moderate evidence for muscle strengthening in the treatment of patients with shoulder impingement. However, the evidence is conflicting with regard to the effectiveness of scapular-focused treatment approach for scapular positioning measure, pain, and shoulder function (Reijneveld et al., 2017). Therefore, the primary objective of the present study was to assess the effect of a combined protocol for the periscapular muscle strengthening and neuromuscular training during the scapular resting position and kinematics. The secondary objective was to evaluate the effectiveness of this protocol in the increase of periscapular muscle strength and improvement of shoulder pain and function. We hypothesized that a treatment protocol would generate changes in scapular kinematics, including an increment of upward rotation, posterior tilt, and external rotation of the scapula and improvement of periscapular muscle strength, pain, and shoulder function.