Biodynamics and Human Performance Center

 Computerized Instrumented Shoulder Model Intra-tester Reliability for Quantification of Forces


Authors: King, JE, Cunningham, TC, Jacobs, CA, Davies, GJ

Institution: Biodynamics and Human Performance Center. Armstrong Atlantic State University. Savannah, GA.

 

King, E, Davies, GJ, Cunningham, TC. Intratester reliability for quantification of forces with accessory and physiological movements using computerized instrumented shoulder models (Research Poster accepted at APTA-CSM, San Diego, CA., 2013) (Nominated for one of the top Orthopaedic Section poster abstracts; Nominated for Grand Prize for best research poster) JOSPT. 43(1):A89 (Abst.-OPO2224), 2013

Abstract


Purpose: The purpose of the study was to determine the intra-tester reliability for quantification of forces of accessory and physiological movements using computerized instrumented shoulder models. We hypothesized the results would demonstrate good reliability.

Methods: 45 physical therapy students (16 Males, 29 Females) 25.2 ± 3.25 years of age, 67.7 ± 3.24 in. height, 153 ± 27.85 lbs weight, performed two trials of movements on a shoulder model, instrumented with transducers calibrated to measure forces applied, in randomized order: anterior glide (AG), posterior glide (PG), internal rotation (IR) and external rotation (ER). The examiner demonstrated each of the techniques before the subjects performed their initial testing. Subjects were permitted a 10 second practice trial before performing the 10 second test trial of Maitland’s Grade IV (IV) and Grade II (II) mobilizations; subjects returned within 24-72 hours to repeat tests.  Transducer signals were captured at 30 Hz, exported to Matlab v2009a (Mathworks, Natick MA) wherethe mean of the last 7 seconds was calculated.

Results: Test-retest reliability was assessed using Intraclass correlation coefficients (ICC’s) of the means using SPSS v17(IBM, Armonk NY). Calculated ICC’s for the test movements are listed in the table.

 

PGII

PGIV

AGII

AGIV

ERII

ERIV

IRII

IRIV

ICC’s

0.486

0.750

0.556

0.614

0.857

0.889

0.754

0.881

Mean

2.296

5.246

2.969

7.141

6.021

14.412

8.495

16.744

stdev

2.631

4.085

2.563

3.747

5.103

8.419

5.003

7.646

 

Conclusion: Portney and Watkins describe ICC’s greater than 0.75 represent good reliability and less than 0.75 reflect moderate to poor reliability. The results showed physical therapy students demonstrated good intra-tester reliability during posterior glide grade IV, external rotation grades II and IV, and internal rotation grades II and IV. All other movements demonstrated moderate to poor reliability.

Clinical Relevance: Physical therapists perform joint mobilizations on patients on a daily basis, but there is no evidence to quantify the forces that are used when these mobilizations are performed. The computerized shoulder model captured the forces during mobilizations applied by first, second, and third year physical therapy students and ICC’s were run using SPSS. The results show that physical therapy students are consistent in some mobilizations, but inconsistent in others. This can be used as biofeedback for these students to try to achieve more consistency in the forces applied during various joint mobilizations. More research is needed to further quantify forces with inter-tester reliability and forces used among practicing clinicians.

 

National Meeting Presentations:

Davies, GJ, King, E, Cunningham, TC. Intratester reliability for quantification of forces with accessory and physiological movements stratified between first, second and third year SPTs using computerized instrumented shoulder models (Research Poster accepted at APTA-CSM, San Diego, CA., 2013). JOSPT. 43(1):A90 (Abst.-OPO2225), 2013

King, JE, Davies, GJ, Cunningham, TC. Using a Computerized Instrumented Shoulder Model to Determine Intra-tester Reliability for Accessory Movement Forces. Research presentation at Alpha Eta National Allied Health Honor Society Student Symposium. Orlando, Fl., October, 2012

International Presentations:

Davies, GJ, King, JE, Cunningham, TC, Jacobs, CA. Computerized Instrumented Shoulder Model Intra-tester Reliability for Quantification of Forces. Research Platform Presentation. 4th International Congress of Shoulder and Elbow Therapists. Nogoya, Japan, April 11-13, 2013

Davies, GJ., Tankovich, MJ., King, JE, Jacobs, CA, Riemann, BL. Manual therapy techniques of the shoulder; objective quantification of forces. Research Platform Presentation. 4th International Congress of Shoulder and Elbow Therapists. Nogoya, Japan, April 11-13, 2013