Measurement and application of bouncing and jumping loads using motion tracking technology

Abstract

State-of-the-art facilities for measuring bouncing and jumping ground reaction forces (GRFs) comprise typically equipment for direct force measurement, i.e. single or multiple floor-mounted force plates. Artificial laboratory conditions and constraints imposed by the direct measurement systems, such as small measuring area of a force plate, can have a strong influence on human ability to bounce and jump, naturally yielding unrepresentative force data. However, when dealing with issues like vibration serviceability assessment of real full-scale structures, such as floors, footbridges, staircases and grandstands, there is a growing need to estimate realistic GRFs under a wide range of natural conditions. This paper presents a novel method in the civil engineering context utilising 'free-field' measurement of human bouncing and jumping forces recorded continuously in time using motion capturing technology transferred and adapted from biomechanical research. Results showed that this kind of data can be used successfully in studies of human-structure dynamic interaction, specifically negative cue effect of a perceptibly vibrating structure on GRFs and energy flow and power in the human-structure system, as well as synchronisation between individuals when bouncing/jumping in groups on more or less perceptibly moving structures.