Application of sensors to investigate tennis racquet dynamics

The need to understand more about the behaviour of tennis racquet strings beyond initial tensioning and after hammer impacts led to tests being conducted by Cross et al, in 2000, which produced information on single-string dynamic properties. In another study by Cross, the effect of string-bed damping on boules was tested for providing COR data from which a damping coefficient can be approximated. Developing further understanding of the string-bed's dynamic properties through information on an actual response to a ball impact was considered here. A method of measuring the string-bed's full response to a ball impact with a linear variable displacement transducer (LVDT) was investigated. The recordings from an a.c. LVDT and a high-speed camera HSC were compared, and it was found that the LVDT's measurement of overall frequency for the complete oscillations after the ball had left the strings was 98.2% in agreement to that recorded by the HSC.