Rotational strength, range of motion, and function in people with unaffected shoulders from various stages of life

BackgroundDifferent measurements are used to assess shoulder function, including range of motion, strength, functional performance and self-report function. To understand disablement, it is necessary to understand the relationship between impairments and function in persons without shoulder problems. This study was conducted to enhance existing comparative data in subjects without upper extremity pathology, and to assess the relationships between impairments (range of motion, strength) and self-reported or measured function/disability. The impact of age, gender and dominance was determined.MethodsTwo-hundred ninety-four subjects with unaffected shoulders were recruited. The subjects (mean age: 37 years old) were divided into three subgroups, 18–39, 40–59, and over 60 years of age. During a single session, at least two of the following variables were measured: self-reported function (shoulder disability scales), range of motion, isometric rotational strength, or upper limb functional performance (FIT-HaNSA). Two-way analysis of variance was used to determine, for each variable, the effects of age and gender. The relationship between the outcomes was established using Pearson product correlations.ResultsMen were significantly stronger than women for all age categories. There was an age-related decline in strength in men in the over-60 age category. Significant negative correlations between strength and range of motion were demonstrated (-0.22