Research Review By Dr. Stacy Irvine©

Date Posted:

September 2009

Study Title:

Current Concepts in the Scientific and Clinical Rationale Behind Exercises for Glenohumeral and Scapulothoracic Musculature

Authors:

Reinhold MM, Escamilla R, Wilk KE

Author's Affiliations:

Massachusetts General Hospital, Boston Red Sox Baseball Club, California State University, American Sports Medicine Institute.

Publication Information:

Journal of Orthopaedic and Sports Physical Therapy 2009; 39(2):105-117.

Background Information:

As more research and data become available about various rehabilitation exercises, it is increasingly important to understand how this research can lead patients to faster recovery from injury. In the shoulder girdle there are numerous exercise approaches, therefore allowing the existing literature to guide us is particularly important. To develop the most effective rehabilitation programs we need to interpret the data from various studies and apply it in a practical setting.

The goal of this study is to provide an overview of the existing biomechanical and clinical literature associated with rehabilitation of the glenohumeral and scapulothoracic musculature.

Pertinent Results:

For the purpose of organizing the vast amount of information in this paper, the shoulder and thoracic musculature was divided into three main areas:
  1. Rotator Cuff Muscles
  2. Deltoid
  3. Scapulothoracic Muscles
According to the authors, the importance of the rotator cuff muscles is determined by their ability to effectively stabilize the dynamic movements of the shoulder joint. Most important with relation to injury, is their ability to prevent superior translation of the humeral head and minimize the chance of subacromial impingement. Joint laxity and instability have been shown to lead to abnormal firing patterns of the rotator cuff musculature. Depending on the injury, the function of each muscle should be considered in an effective rehabilitation program.

The main portion of this article outlines recommended exercises for the various muscles included in the above groupings. These recommendations are based on anatomical, biomechanical and clinical concepts and literature. In several cases EMG data were used to determine effectiveness of a particular exercise, along with force predictions based on 3-D biomechanical shoulder models. The following list is the first exercise shown for each specific muscle group and represents the exercise suggested to be the most effective by the authors of the study:

Supraspinatus: Full can
  • elevation in the scapular plane with humeral external rotation (thumb up)
  • this exercise has shown slightly superior EMG results and in theory allows proper clearance of the greater tuberosity under the acromion during the exercise
Infraspinatus and Teres Minor: Side lying external rotation
  • with patient in side lying position, place a towel or roll between the elbow and ribcage to reduce capsular strain
  • patient then externally rotates the arm with the elbow in 90° of flexion
  • the authors note that standing external rotation with the arm in the scapular plane (at 45° of abduction) is a viable alternative (be aware of proper scapular positioning with this exercise)
Subscapularis: “Diagonal exercise”
  • shoulder starting position is 90° of abduction and external rotation in the coronal plane
  • using tubing or a pulley (behind the patient) – the arm is then internally rotated and horizontally adducted simultaneously, with a slight downward diagonal path
  • the authors also point out that the push-up plus, dynamic hug, D2 PNF, and scapular clock exercises all have high subscapularis EMG levels
Deltoid:
  • data suggest that the three heads have different roles during different should movements
  • exercises should be tailored to the individual patient depending on their injury
  • it appears that the middle deltoid has the highest impact on superior humeral head migration, therefore exercises that preferentially activate this part of the deltoid (ex. the empty can) should be minimized for most patients
  • conversely, activity of the posterior deltoid does not seem to impact abduction or superior humeral head migration, therefore exercises such as the prone full can, which has high levels of posterior deltoid and rotator cuff activity, should be safe for most patients
Serratus Anterior: Push-up Plus (with feet elevated)
  • this is a standard push-up with a “plus” of scapular protraction at the end range
  • some evidence suggests that elevating the feet (making it a decline push-up) can increase EMG activity while keeping the arm out of higher elevations that can aggravate impingement syndromes
  • there are other good options too such as the dynamic hug and scapular punch at 120° (jabbing protractions using tubing or a cable) exercises
Lower Trapezius: Prone Full Can
  • keeping the fiber orientation in mind, this exercise is performed prone – the patient elevates their arm in the scapular plane (45°) with the thumb pointing up
  • prone horizontal abduction with the arm at 90° and externally rotated can also be useful
Middle Trapezius: Prone Row
  • with patient prone and holding dumbbells or tubing, the elbows are drawn posteriorly (kept close to the torso) – squeezing the scapulae downward and backward
Upper Trapezius: Shrug
  • imparts scapular control without any arm elevation
  • overall goal of trapezius exercises is to create an appropriate ratio of LOWER/middle fiber activity compared to upper
Rhomboids and Levator Scapulae: Prone Row
  • see above
  • prone horizontal abduction with the arm at 90° and externally rotated can also be useful
An important recommendation by the authors was that clinicians carefully consider and emphasize posture and scapular retraction when performing all rehabilitative exercises. Finally, a common recommendation of limiting the amount of weight used when performing rehabilitative exercises seems to be unnecessary based on the results of two recent EMG studies. These findings indicated that lifting heavier weights will not compromise the effectiveness of the exercise, thus the weight selection should be based on the goals and performance requirements of the patient.

Clinical Application & Conclusions:

Understanding the biomechanical factors associated with normal shoulder movement is not a simple task. This paper highlights the main areas that need to be understood by clinicians and therapists prescribing exercise programs for shoulder rehabilitation. The recommended exercises can be useful for anyone working on shoulder rehabilitation with athletes or the general population. Experience using the exercises listed by the researchers is important to the readers’ ability to understand the concepts being presented. These exercises are not well defined or explained completely in the paper (we have supplemented the descriptive information above where necessary), although they are exercises common to most shoulder rehab programs.

Study Methods:

The authors of this study reviewed the existing literature pertaining to shoulder biomechanics, along with EMG data and their clinical experience to determine the most effective rehabilitation exercises for the glenohumeral and scapulothoracic musculature. The researchers chose commonly used exercises for shoulder rehabilitation and chose, based on the above information, the exercises they felt were best for each muscle.

Study Strengths / Weaknesses:

A comprehensive review of shoulder related research done by experienced clinicians can be used as a valuable tool for any practitioner. A weakness of this type of study is that the format often alternated between research review and clinical opinion. It would have been helpful to have a standardized format, used in most literature reviews, comparing the research that was included for reference. There is little information provided about how the EMG data was obtained and the conclusions, or in this case, exercises chosen were often based on this information.