Determination of the Cutoff Frequency of Smoothing Filters for Center of Pressure (COP) Data via Kinetic Energy in Standing Dogs

This article investigates the determination of the optimal cutoff frequency of smoothing filters for motion data based on kinetic energy. The underlying hypothesis is that an upper limit of kinetic energy can serve as a basis for setting the cutoff frequency. To illustrate this, postural sway in standing dogs was analyzed based on the movement of their center of pressure (COP). The method was tested on 12 clinically healthy dogs that met specific inclusion criteria. The results show that a cutoff frequency of 6 Hz, derived from an individual kinetic energy calculated from the COP velocity of 5 cm/s, provides the best representation of postural sway, while 10 Hz filtered data was sufficient in only 6 of 12 dogs, and unfiltered data unsuitable in 12 of 12 dogs. The study highlights that the choice of cutoff frequency is crucial for data quality and proposes a biologically motivated method based on kinetic energy. This method could lead to more precise and meaningful results in motion analysis.