An Introduction to Time-frequency Low-pass Filter Methods in Biomechanics

Dr. Neal Smith & Dr. Simon Augustus

In a variety of human movements, ranging from walking to running, landing to kicking, we will attempt to apply some kind of mathematical filter to our kinematic (and kinetic) data, reducing the inherent noise within the signal that propagates errors in further calculations. However, the extent to which these body collisions alter the frequency content of the signal has remained relatively unknown. Once this information is identified, it is plausible to optimise the use of contemporary low-pass filter techniques that vary the magnitude of noise reduction over different phases of a task (i.e., transitions from aerial to ground contact). This workshop will explore the theory of the frequency content of these types of collision, along with practical demonstrations, and involvement of the audience with pre-prepared data sets. Participants will require a working version of MATLAB to participate in the workshop.


Dr Neal Smith is a Reader in Biomechanics at the University of Chichester, UK. His research interests are mainly centred around the biomechanics of football, with a focus on collisions.

Dr Simon Augustus is a Lecturer in Sport Biomechanics at Kingston University, London, UK. His PhD investigated the mechanics of ball kicking and he used a time-frequency (fractional Fourier) low-pass filter to better understand the nature of foot-to-ball collisions as part of this work. He is now applying the time-frequency method to different movement tasks involving collisions (e.g. foot-to-ground contact during locomotion) to: a) help improve researcher's abilities to precisely estimate kinematic and kinetic parameters, and b) contribute to enhancing sports performance and reducing injury.