Investigation of the Correlation between Factors Influencing the Spectrum of Center of Pressure Measurements Using Dynamic Controlled Models of the Upright Stand and Subject Measurements

Measuring of the center of pressure (CoP) is one of the most frequently used quantitative methods for quantifying postural performance. The aim of the study is to describe differentiation criteria in the CoP-track for the clinical picture of chronic unspecific back pain. In this study, dynamic models loaded with multi-variable controls are used to determine whether biomechanical questions for upright posture can be answered. These models are particularly well suited for investigating the kinematics and the influence of the influencing disturbance variables. These investigations are extended by power density spectrum (PSD) analyses of CoP measurements on 590 subjects with and without chronic non-specific back pain. Pain patients show an average of 0.5 Nm2 more area under the spectrum than the pain-free reference group. In the power density spectrum different frequency ranges can be assigned to specific body oscillation. Among others, the frequency range between 0.5–0.8 Hz corresponds to the hip movement. In the range around 0.2 Hz, the movements are reflected in the upper body. Patients with back pain experience less activity in certain, individual areas.