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Tuesday, June 6, 2023

The Effect of Stretching and Strengthening Exercises on Three-Dimensional Scapular Kinematics

Brent Brookbush

Brent Brookbush


Research Review: The Effect of Stretching and Strengthening Exercises** on Three-Dimensional Scapular Kinematics**

By Jill Wosmek, MA, ATC

Edited by Brent Brookbush, DPT, PT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Wang, C., McClure, P., Pratt, N., Nobilini, R. Stretching and Strengthening Exercises: Their Effect on Three-Dimensional Scapular Kinematics. Arch Phys Med Rehabil. 1999 vol. 80, 923-929 - ABSTRACT

Scapular Motion - http://bmsi.ru/_uf/image/5555(80).gif

Why is this relevant?:

This study adds to the growing body of research regarding altered scapular kinematics and shoulder pathology. Further, this study demonstrated that exercise-based intervention may result in positive changes in scapular motion. Evidence to support conservative treatment options, including corrective exercise/therapeutic exercise is of interest to all practicing human movement professionals. This research review looks scapular kinematics from an injury prevention component and attempts to quantify their treatment plan specifically.

Questions: Can a practitioner visually identify asymptomatic upper body dysfunction and forward head posture and implement a program that can affect the scapula positioning specifically? Can visual identification of this dysfunction result in a specific exercise plan that correlates with statistical change in scapular position? Let’s take a look!

Study Summary

Study DesignStudy Design: Repeated measures design, pre and post 6-week program
Level of EvidenceType IIB - Quasi-experimental Design
Subject Demographics
  • Subject Demographics: 20 asymptomatic subjects with forward shoulder posture
  • Age: mean age 30.1
  • Gender: 9 men, 11 women
  • Characteristics: asymptomatic shoulder, forward shoulder posture according to a plumb line assessment
  • Inclusion Criteria: no subject had been treated for shoulder dysfunction or had engaged in shoulder exercises in the previous 3 months
  • Exclusion Criteria: if they had an overt shoulder trauma or surgery, had symptoms resulting from cervical or other neural problems, had acute pain around the shoulder area or were younger than 18 years old
Outcome Measures
  • All measurements using the Metrecom were completed by the same investigator throughout the study.
  • Isometric strength measurements were completed on the right arm of all 20 subjects, regardless of handed-ness. Positioning and stabilization was similar to other well-documented EMG studies.
    • Shoulder rotation was measured at 90⁰  of abduction and 90⁰ of external rotation, with the elbow flexed and forearm oriented vertically.
    • Shoulder horizontal adduction and abduction strength was measured from the same position, but the resistance pad was placed on the humerus, just proximal to the humeral epicondyles.
    • Before the measured trials, one sub maximum and one maximum warm-up set were performed. During data collection, the subject was required to produce three maximal isometric contractions for five seconds each.

  • Orientation and position of the scapula was calculated based on the model shown below (Image 2).
ResultsAll data was measured using MANOVA .
  • The strength of horizontal abduction and internal and external rotation increased after exercise (p < .01).
  • The anterior inclination of the thoracic spine decreased, and the glenohumeral contribution to arm elevation increased (p < .01).
  • Resting scapular posture did not change.
  • As the arm was abducted to 90 degrees, the scapula showed less upward rotation and less superior translation after the exercise program (p < .01)
  • No significant change in ratio measurements of shoulder external/internal rotation or horizontal adduction/abduction strength.
  • Prior to the intervention the scapula maintained a position of internal rotation and/or an increase in internal rotation was noted throughout the entire range of shoulder abduction. Post exercise, the scapula internally rotated as the shoulder abducted from resting to 90⁰, and then externally rotated from 90⁰ of abduction to end range.
Conclusions Isometric shoulder external rotation, internal rotation and horizontal abduction force were increased by implementing a 6 week exercise plan in all subjects.  The exercise plan did not significantly alter the forward shoulder posture even though it promoted scapular stability and a relative increase in glenohumeral motion during elevation.
Conclusions of the ResearchersUtilization of a 6 week Theraband exercise plan may be beneficial for increased strength, but knowing the limitations with this study specifically the researchers are recommending additional work exploring a more dynamic strengthening plan and functional movement assessment.

Wang 3
Caption: Wang 3

Image from study, describing the kinematic relationships used to determine scapular and humeral motion.

The exercise program used in the study included the following:

  • Intensity: The color of Theraband was determined after the evaluator cued the subject for 5 reps; categorizing them into green , blue or black resistance groups. The color of the theraband correlated to loads between 2.6 kg to 15 kg (depending on exercise).
  • Frequency: All subjects were required to perform a standardized home exercise program three times per week for 6.
  • Progressive Load: One set of 10 reps/session of each exercise for the first 2 weeks, with five more reps added to each set set for each 2 week period that followed. The Theraband intensity did not change.
  • Exercise Type:
  1. Bilateral scapular retraction
  2. Unilateral shoulder shrugging/elevation
  3. Unilateral shoulder abduction
  4. Unilateral shoulder external rotation from a neutral position

The stretching portion of the program included the following:

  • “Corner stretching” was the term used to describe the pectoralis stretch. The subjects were instructed to lean into the corner of a wall with their shoulder and elbow in the 90/90 position for 10 seconds, for 10 repetitions. Five additional reps were added every 2 weeks.

Pectoralis Major and Minor Static Stretch (Wall Stretch):

The exercise selection was based off two previous EMG studies, with the goal of reducing muscle activity in the glenohumeral internal rotators and the horizontal adductors . Wang et al. hypothesized that changes noted in gleno-humeral internal rotation strength may have been due to the eccentric load placed on these muscles during stretching.

Review & Commentary:

The strength of this study includes careful pre- and post-test measurements with high reliability, using the same device, set-up and evaluator. The sample size was small, but the selection of a healthy asymptomatic population with Upper Body Dysfunction UBD , may be evidence that an exercise intervention is effective, even in the absence of pain, in a population that may be more susceptible to developing shoulder pathology in the future. If future research, does in-fact support the notion that UBD leads to shoulder pathology (a widely held belief, based on clinical experience and similar research on other joint systems - Knee & Core ), this study would be evidence that an exercise based intervention may be effective for preventing injury.

This study is not without limitations. Eluded to before, the sample size is small (20 subjects). There was no specific reason noted in the article for the limited sample size; especially, considering this is a commonly seen posture in our society. Additional limitations include the method in which strength was measured; as activities of daily living and sport are not exclusively related to isometric strength. Further, the authors of this review believe a more sophisticated intervention may have produced better results. Want et al. did mention their intent to develop research that related alterations in scapular kinematics to "functional activities," and "dynamic strength" in the future.

Why is this study important?

Studies like this one, showing a correlation between intervention and intended changes in motion, provide clinicians with evidence-based information for improving practice in both rehabilitating and preventing injury. Further information may be provided by Reinold et al.'s work exploring exercise selection and EMG analysis specifically designed to reduce forward shoulder posture, demonstrating the muscle activation associated with specific exercises. The exercises used in this study were effective for certain clinical goals (increased strength of stabilizers), but less effective for others (changes in resting position of the scapula and thoracic spine). This may imply that these exercises are a good start, but leave room for improvement.

How does this study affect practice?

The ability to assess static and dynamic postural dysfunction/movement impairment , including the forward shoulder posture used as inclusion criteria in this study, may provide additional information for the development of rehabilitation and prevention programs. The Upper Cross Syndrome defined by Dr. Janda has been systematically reviewed for years, and the model of Upper Body Dysfunction (UBD) used by the Brookbush Institute is built upon this model with the addition of current concepts in human movement science, additional research and clinical findings. This study provides evidence that exercise intervention may have an affect on Upper Body movement impairments, even in those individuals who have yet to develop significant pathology and/or pain.

How does it relate to Brookbush Institute Content?

This study demonstrates that an exercise intervention, similar to those demonstrated in the article Upper Body Dysfunction Sample Routine and Corrective Exercise , may lead to positive changes in scapular and gleno-humeral kinematics in those individuals with Upper Body Dysfunction . Further, this may be true for symptomatic and asymptomatic individuals. Although, the Brookbush Institute does not necessarily recommend the specific exercises used in this study, the concepts and intent of the study are similar to the approach discussed in the article hyper-linked above. More research is desperately needed to determine the effectiveness of an integrated intervention model, and whether that model has the potential to prevent and/or reduce the occurrence of injury. Studies like the one reviewed in this article provide one more piece to a puzzle, that when completed, will reveal a complete picture of the human movement system.

Sample Shoulder External Rotator Activation Exercises:

External Rotator Isolated Activation

External Rotator Isolated Activation Progression

External Rotator Reactive Activation

External Rotator Kinesiology Taping


  1. Wang, C., McClure, P., Pratt, N., Nobilini, R. Stretching and Strengthening Exercises: Their Effect on Three-Dimensional Scapular Kinematics. Arch Phys Med Rehabil. 1999 vol. 80, 923-929.
  2. Manchester-Bedford Myoskeletal:Upper Cross Syndrome photo cred. http://www.mbmyoskeletal.com/online-courses/online-courses/learning/the-crossed-syndromes/
  3. Page, P., Frank, C., Lardner, R. Assessment and Treatment of Muscle Imbalance: The Janda Approach. Benchmark Physical Therapy Inc., 2010.
  4. Sahrmann, S. Diagnosis and Treatment of Movement Impairment Syndromes. Mosby Inc., 2002.
  5. Reinold, M., Escamilla, R., Wilk, K. Current Concepts in the Scientific and Clinical Rationale Behind Exercises for Glenohumeral and Scapulothoracic Musculature. J of Ortho & Sports Phys Therapy. 2009 vol. 39, 105-115.

© 2015 Brent Brookbush

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