In-vivo Measurements of Force and Humeral Movement During Inferior Glenohumeral Mobilizations

• Subject Demographics
  • Age (Mean (Standard Deviation), Range): 23 (2.3), 22-30
  • Gender: 15 F, 8 M
  • Height (cm): 175.3 (12.2), 152.0-202.0
  • Weight (kg): 72.4 (16.3), 48.5-121.1
  • BMI (kg/m²): 23.8 (4.4), 18.9-34.8

• Characteristics of the Study:
  • Experimental procedure
    • Each subject was positioned supine, with the shoulder in the "open-packed" position (55° of abduction, 30° of horizontal adduction), which was measured using a universal goniometer. The scapula was stabilized by the subject's bodyweight.
    • A 40 mm linear transducer of an ultrasound machine was positioned in the frontal plane over the suprahumeral joint space allowing visualization of the lateral aspect of the acromion and the superior aspect of the humeral head.
    • A "rest" picture was taken with the ultrasound machine prior to mobilization.
    • A single examiner with over 25 years of experience performed three different grades of mobilizations in consecutive order, verbalizing the grade to another examiner who was recording the data from the ultrasound machine. The mobilizations were defined as follows:
      • Grade 1 - "A loosening movement that nullified joint compressive forces and produced slight joint movement."
      • Grade 2 - "A tightening movement that tightened shoulder tissues until the examiner felt a marked resistance."
      • Grade 3 - "A stretching movement after all tissues were taut in which movement was maximal and resistance to movement had increased rapidly."

    • In order to record the force required for each grade of mobilization, the examiner administered the technique through a handheld dynamometer at the proximal humerus. The clinician was blinded to the amount of force being used during each grade of mobilization and did not have the ability to view the ultrasound imaging during the mobilizations.
    • Ultrasound images were recorded after the therapist verbalized the grade of mobilization.
    • The clinician rested for 30 seconds after each trial, with a total of three repetitions per shoulder. The procedure was repeated for both shoulders (dominant and non-dominant).
    • The order of testing on the dominant and non-dominant shoulder was randomized prior to the start of data collection.

  • Measuring the Degree of Inferior Glenohumeral Translation
    • A single examiner utilizing ImageJ software measured the degree of inferior glenohumeral translation.
    • For each image, the examiner drew a horizontal line at the level of the superior aspect of the acromion and a second line tangent to the superior humeral head. The distance between the two lines were measured for each grade.
    • The translation measurements were made by subtracting the initial distance between the humeral head and the superior aspect of the acromion from the distance measured during each grade of mobilization.

  • Statistical Analyses
    • Statistics were calculated for the movements and forces recorded during each grade of mobilization.
    • Intraclass coefficients (ICCs) were calculated for movement and force values for each grade of mobilization.
    • Standard error of measurement (SEM) was also calculated for humeral movement and for mobilization force.
    • A One-way ANOVA was done to investigate the relationship of repetition, mobilization grade, and hand dominance on dependent variables of mean humeral head movement and mean mobilization force.

• Inclusion Criteria:
  • Between the ages of 18-55
  • No current or past history of upper extremity or spine pain, surgery, or injury

• Exclusion Criteria:
  • Any current or past musculoskeletal or neuromuscular conditions related to the shoulder, arm, or neck
  • Pregnant
  • Did not speak English
  • Current or past history of connective tissue disorders
  • History of hypermobility or hypermobility-related conditions
  • Currently taking steroids

• Intraclass correlation coefficients (ICCs) for humeral head movement and force values for each grade of mobilization
• Humeral head movement and force recorded during each grade of mobilization
• Relationship of repetition, mobilization grade, and hand dominance on humeral head movement and mobilization force

Results Table 2. -From Witt DW, Talbott NR. In-vivo measurements of force and humeral movement during inferior glenohumeral mobilizations. Manual Therapy. 2016. 21: 198-203.

Caption: Witt DW, Talbott NR. In-vivo measurements of force and humeral movement during inferior glenohumeral mobilizations. Manual Therapy. 2016. 21: 198-203.

Table 3. - From Witt DW, Talbott NR. In-vivo measurements of force and humeral movement during inferior glenohumeral mobilizations. Manual Therapy. 2016. 21: 198-203.

Our ConclusionsThe Kaltenborn grading system may be used reliably in a rehabilitation settings for inferior glenohumeral joint mobilizations . Future studies are needed to determine the effect inferior glenohumeral joint mobilizations have on shoulder flexion and abduction range of motion and/or pain.Conclusions of the Researchers A single clinician can reliably produce Kaltenborn grades 1-3 inferior glenohumeral joint mobilizations with significantly different movement and forces occurring with each mobilization grade. Forces, but not humeral head movement, were significantly different when the clinician was mobilizing with the dominant versus non-dominant hand. Future research is needed to elucidate the reason for this discrepancy.

Caption: The common position manual therapists use to assess the shoulder joint. This is commonly referred to as the "open-packed" position of the shoulder.

The common position manual therapists use to assess the shoulder joint. This is commonly referred to as the "open-packed" position of the shoulder.

Review & Commentary:

This 2016 study was the first study of its kind to quantify the amount of force and humeral head displacement during Kaltenborn grades 1-3 mobilizations using ultrasound technology. The results of the current study lay the foundation for future research on clinical outcomes utilizing inferior glenohumeral joint mobilizations and its effect on individuals with shoulder pathologies.

The study had many strengths, including a strong methodology for analyzing the data, use of live subjects, and the novel nature of the study results. In order to accurately measure humeral head displacement and the force applied by the clinician during each grade of mobilization, the authors paired hand-held force dynamometery with real-time ultrasound technology. These technologies enabled precise measurements of the amount of humeral head movement and applied force for each grade of mobilization. The methodology of the study also blinded the clinician to the real-time ultrasound feed and hand-held dynamometry force recordings. Clinician blinding reduces interviewer bias, which occurs when a clinician is aware of the results of the outcome variables of interest (humeral head displacement and applied force) during the experimental procedure. Inclusion of a power analysis also strengthened the results of this study. A priori power analyses determines the minimum amount of subjects needed in an experiment to achieve a statistically significant effect of the intervention. The use of live subjects increases generalizability of the results to the clinical setting. Previous research on inferior glenohumeral joint mobilizations have been done on cadavers (2), which obviously do not have functioning neuromusculoskeletal systems. Other studies have shown that during distraction and posterior glenohumeral joint mobilizations in live subjects, the rotator cuff generates electromyographic activity (3). Last, this study provides objective data showing that an experienced clinician can reliably produce Kaltenborn grades 1-3 mobilizations in live subjects.

Weaknesses that should be noted prior to clinical integration of the findings include the absence of assessing muscle guarding, the use of a healthy population free of shoulder pathologies, and the clinician's experience. Muscle guarding could influence the amount and degree of humeral head translation and/or the force needed to mobilizethe joint. Electromyographic measurements could aid in determining the relationship between shoulder muscle activation, humeral head migration, and the force applied by the clinician during each grade of mobilization. The subjects in this experiment were healthy, young, and free of shoulder pathology. This limits generalizability to the populations where this technique is commonly practiced. Last, a single examiner conducted the inferior mobilizations. This clinician had 25 years of orthopedic clinical experience. It is unknown whether similar reliability measures would be obtained in individuals with less experience. Further, this research does not provide any data regarding inter-tester reliability - whether various clinicians practicing in the same clinic would use similar force during similar techniques on various individuals.

How This Study is Important:

Professionals working in rehabilitation settings commonly use glenohumeral joint mobilizations with their clients/patients to improve joint mobility and range of motion (ROM) into shoulder flexion and/or abduction and/or to reduce pain. The current study is the first of its kind to show that a clinician can reliably reproduce Kaltenborn, grades 1-3 inferior glenohumeral joint mobilizations in-vivo. Each grade of mobilization performed by the clinician was shown to produce different amounts of motion (inferior glide) using significantly different forces.

How the Findings Apply to Practice:

The results of the study suggest that it is possible for individuals to reliably reproduce Kaltenborn grades 1-3 mobilizations on live subjects. However, as this was the first study of its kind, the focus was to objectively quantify the different amplitudes and forces needed for each grade of mobilization. Additional studies are needed to determine clinical effectiveness of this technique on shoulder range of motion and/or pain.

How does it relate to Brookbush Institute Content?

As with all interventions, effectiveness will be determined by appropriate usage. The Brookbush Institute suggests using joint mobilizations in individuals with range of motion restrictions when muscular interventions (such as foam rolling, release techniques, stretching ) are not effective.

To determine intervention's effectiveness clinically, the Brookbush Institute recommends "assess, intervene, and re-assess." In the case of shoulder range of motion restrictions, recording shoulder flexion and/or abduction range of motion using a goniometery prior to joint mobilization can provide objective data on the efficacy of the intervention. Human movement professionals (DPT, DCs, ATCs) whose scope of practice includes manual therapy can utilize inferior glenohumeral joint mobilizations to improve joint range of motion. Future videos will be released on manual mobilization techniques including inferior glenohumeral joint mobilizations. Other human movement professionals can utilize self-administered general shoulder joint mobilizations with their clients to accomplish similar goals.

The following videos are commonly used assessment techniques and interventions to treat shoulder range of motion restrictions.

Brookbush Institute Videos

Shoulder Flexion Goniometry

Shoulder Internal Rotation Goniometry

Self-Administered Posterior Shoulder Release

Self-Administered Shoulder Mobilization

Posterior Shoulder Stretch (Sleeper Stretch)

References:

1. International Maitland Teachers association. A tribute to the life and work of G.D.Maitland 1924-2010. Manual Therapy. 2010; 300-301
2. Hsu AT, Ho L, Hedman T. Immediate response of glenohumeral abduction range of motion to a caudally directed translational mobilization: a fresh cadaver simulation. Arch Phys Med Rehabil. 2000; 81(11): 1511-1516.
3. Swanson BT, Holst B, Infante J, et al. EMG activity of selected rotator cuff musculature during grade III distraction and posterior glide glenohumeral mobilization: results of a pilot trial comparing painful and non-painful shoulders. J Man Manip Ther. 2016 February; 24(1): 7-13.

© 2016 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -