Reliability and validity of portable dynamometers in testing shoulder and shoulder girdle strength: A systematic review
Authors: Minder Ursina , Perret Claudio , Arnet Ursina , Bossuyt Fransiska M. 
Published: February 2024

Introduction
The prevalence of shoulder pain is high in overhead athletes and in wheelchair users with a spinal cord injury (SCI). Especially in the latter, shoulder pain can have detrimental consequences for an individual's mobility, participation, and quality of life. Shoulder problems have been associated with high and/or repetitive loads induced by for example overhead activities, as well as manual wheelchair activities (Leong et al., 2019; Morrow et al., 2011). Modifiable risk factors for shoulder pain are related to the capacity of the shoulder musculature and include the relative strength or lack of force in certain shoulder muscles (Mulroy et al., 2015). Although isokinetic dynamometers are considered the gold standard in assessing muscle strength, they are typically not available in a therapy or training setting. Strength measurements with portable dynamometers offer a more feasible and financially affordable alternative. To assess changes in muscle strength over time, reliable and valid shoulder and shoulder girdle muscle strength tests are required. Therefore, the aim of this study was to identify validated and reliable portable dynamometer protocols to assess changes in shoulder strength in the general population and wheelchair users with SCI over time.
Methods
A literature search was performed with defined terms from the three main concepts “shoulder joint”, “strength testing” and “reproducibility of results”. The electronic search strategy was developed with the help of a librarian and adapted for the following databases: PubMed (Medline), Cochrane Library (Central register of controlled trials), Web of Science (Core Collection), CINAHL. The population of interest was the general population (≥ 18 years) with and without shoulder pain with a special focus on wheelchair users with SCI. Title and abstract screening, full-text screening, quality assessment and data extraction was performed using Covidence.org. For quality assessment selected boxes from the “COSMIN Risk of Bias tool” were used. Data extraction was performed by two independent authors. The main outcome measures extracted where test-retest reliability (intraclass correlation coefficient, standard error of measurement and minimum detectable difference) and concurrent validity (intraclass correlation coefficient).
Results
Trough systematic search 8,020 studies were identified for screening. Initially 2,267 were excluded as duplicates and 5,647 were excluded for not meeting the inclusion criteria. 106 full-texts have been screened. As data extraction is ongoing the results of reliability and validity of portable dynamometer in testing shoulder strength will be presented at the conference.
Discussion/Conclusion
As data extraction is ongoing the discussion and conclusion will be presented at the conference.
References
Leong, H. T., Fu, S. C., He, X., Oh, J. H., Yamamoto, N., & Yung, S. H. P. (2019). Risk factors for rotator cuff tendinopathy: A systematic review and meta-analysis. Journal of Rehabilitation Medicine, 51(9), 627-637. https://doi.org/10.2340/16501977-2598
Morrow, M. M. B., Kaufman, K. R., An, K.-N. (2011). Scapula kinematics and associated impingement risk in manual wheelchair users during propulsion and a weight relief lift. Clinical Biomechanics, 26(4), 352-357. https://doi.org/10.1016/j.clinbiomech.2010.12.001
Mulroy, S. J., Hatchett, P., Eberly, V. J., Lighthall Haubert, L., Conners, S., & Requejo, P. S. (2015). Shoulder strength and physical activity predictors of shoulder pain in people with paraplegia from spinal injury: Prospective cohort study. Physical Therapy, 95(7), 1027-1038. https://doi.org/10.2522/ptj.20130606