Shoulder Joint Range of Motion in Healthy Adults Aged 20 to 49 Years

Abstract

Studies of adults aged 50 years and older have shown that shoulder range of motion (ROM) is significantly less than the norms reported by the American Academy of Orthopaedic Surgeons (AAOS) and decreases with age. However, there has been little investigation of the shoulder ROM of younger adults. The aims of this study were to measure the ROM of healthy younger Australian adults aged 20 to 49 years to (1) pool with data on healthy older Australian adults aged 50 years and older from the study by McIntosh et al (2003) to provide shoulder ROM values across the adult life span; (2) compare their shoulder ROM with AAOS norms; and (3) determine the effect of background factors (age, gender, body mass index [BMI] and current activity level) on active shoulder ROM. Goniometric measurement of bilateral passive and active shoulder flexion, abduction, internal rotation and external rotation of 72 participants was compared with the AAOS norms using one-sample t-tests. The effect of the background factors on shoulder ROM was analysed using univariate General Linear Models. Significantly lower active and passive ROM (p≤0.001) for all movements compared with AAOS norms was found. Active shoulder flexion, abduction and internal rotation were not significantly affected by any of the background factors. Decreased active external rotation was found for males (p = 0.020) and for older (p = 0.048) and less active (p = 0.048) participants. This study highlights the inaccuracies of the AAOS norms for younger adults aged 20 to 49 years and shows that age, gender, BMI and current activity level do not consistently have an impact on active shoulder ROM in this age group. The relevance of the AAOS norms to other joints needs investigation.