Isometric shoulder strength: Normative Australian population data and associated factors

Background: Age and sex are known predictors of isometric shoulder strength and therefore must be accounted for when noting strength values or administering assessments such as the Constant Score. Given the popularity of the Constant Score, it is important to ensure protocols and values remain clinically relevant and are representative of the intended population.

Method: Isometric shoulder strength was recorded for 511 participants without shoulder pathology using the Chatillon^TM hand-held dynamometer. Data were stratified by age and sex for comparison with published normative strength series. Other demographic variables were evaluated using linear regression models.

Results: Normative values for shoulder strength were generated. Age (p = .003, $r^2=.010$ ) and sex (p < .001, $r^2=.026$ ) were significant predictors of shoulder strength. Height (p = .03, $r^2=.010)$ was a significant predictor of strength in females and weight was a significant predictor of strength in males (p < .001, $r^2=.017$ ). Hand dominance was also significant, with non-dominant shoulder strength associated with higher strength in females (p < .001, $r^2=.081$ ) and lower strength in males (p < .001, $r^2=.154$ ).

Conclusion: This study generated normative shoulder strength values for a sample of the Australian population and provided a comparison between other normative scores. Significant demographic predictors in addition to age and sex were identified.

Level of evidence: III.