Integrating Biomechanics and Health Psychology: Biophysical and Psychological Considerations for Spine and Shoulder Musculoskeletal Disorders

Musculoskeletal disorders of the spine, predominantly the low back, and shoulder are common, costly burdens that impact health, function, occupation, and quality of life. Therefore, the overall goal of this research was to integrate biomechanics with health psychology to explore biophysical and psychological considerations towards understanding the relationship between these two regions for improving ergonomics, clinical biomechanics, and rehabilitation research and practice. The pathways of inquiry were achieved through a description of historical and relevant literature complemented by Canadian work-related lost time injury claims data demonstrating consistent rates of shoulder and low back claims. A question of the functional relationship between the shoulder and spine was answered using a large lab based cross-sectional, on over 160 young adults to determine the ROM and curvature relationship between the shoulder and spine. Although a moderate relationship was found in an asymptomatic sample, there were selected biophysical and psychological modifiers related to previous injury and spine curvature that were suspected considerations. Consequently, previous injuries and current Kinesiophobia and fear-avoidance beliefs were measured in this group of young adults, where most individuals with previous shoulder/low back injury still had Kinesiophobia irrespective of length of time since injury. Concurrently with the lab-based study, body composition was a hypothesized biophysical modifier of interest, however, within a sample of >160 young adults, the range of body composition was small and within established body mass index cut-offs for normal weight. Therefore, a systematic review was conducted to evaluate the relationship between body composition and thoracolumbar spine range of motion and curvature reported in the literature. There was strong evidence to suggest a positive relationship between body mass index and thoracic kyphosis and lumbar lordosis when body mass index was greater than normal cut-offs, that is in overweight and obese ranges. This body of evidence reports that the shoulder and spine share a functional ROM and curvature relationship and that the biophysical consideration of body composition and the psychological consequence of Kinesiophobia after a previous injury are important modifiers in the measurement of the musculoskeletal function of the shoulder and spine.