Influence of body weight or composition on clinical, biomechanical and muscular condition of individuals with patellofemoral pain: a prospective study

Abstract

The increase in body weight is a public health problem associated with several musculoskeletal disorders. Recently, a systematic review reported that individuals with patellofemoral pain (PFP) have a higher body mass index (BMI) compared to asymptomatic individuals. Recent studies from our group have also reported that women with PFP have higher percentage of body fat and less muscle mass compared to controls; and that a higher percentage of body fat and a lower percentage of lean mass are associated with worse functional capacity and lower torque of the knee and hip muscles in individuals with PFP. The increase in body weight is commonly associated with a decrease in the physical activity level and can influence several factors that are altered in individuals with PFP, such as pain, function, psychological factors, quality of life, muscle torque, and biomechanical parameters. However, no longitudinal studies have been performed to investigate the influence of body weight, body composition, and physical activity level on the long-term clinical, biomechanical, and muscular condition of men and women with PFP. Therefore, this project aims to investigate the influence of body weight, body composition and physical activity level on pain, function, quality of life, psychological factors, objective function, muscle torque of the knee and hip muscles, and patellofemoral stress in individuals with PFP over a 3-year period. Men and women with PFP and aged between 18 and 35 years will be recruited to participate in this study. Self-reported data (ie, pain, function, quality of life, kinesiophobia, pain catastrophism, level of physical activity), anthropometric measures (ie, body weight, height, skinfolds), body composition, performance in functional tests such as the single leg hop test, maximum torque of the knee extensors and flexors and hip abductors, and biomechanical data will be obtained, with the latter being used to calculate patellofemoral stress. Statistical tests will be used to compare the variables of interest after 3 years (baseline x follow up). Linear regressions will be performed to investigate how changes in body weight, body composition and physical activity level explain changes in the clinical, biomechanical and muscle capacity of men and women with PFP. For those individuals who had no clinically important change in body weight (less than ±7% change in body weight), linear regressions will be calculated to investigate how much body weight and body composition after 3 years explain clinical, biomechanical, and capacity muscle of men and women with PFP. (AU)