Estimation of force during vertical jumps using body fixed accelerometers

A method of estimating force using an accelerometer is presented. This model is based on estimating the resultant acceleration of a body at its centre of mass using a triaxial accelerometer. A data set of ground reaction forces are gathered using a force platform, which is used as the control for this experiment. Signal processing techniques for resampling the accelerometer signals, along with a method of cross correlation to align the force platform and accelerometer traces are used. The purpose of this study was to compare force calculated using accelerometer data from the SHIMMER device, with force platform data on counter movement and drop jumps, for use in sports biomechanics. The method was validated using twelve physically active adults who performed 5 counter movement jumps and 5 drop jumps from a height of 0.30 m. An accelerometer was attached near the participant´s centre of mass and simultaneous force and acceleration data were obtained for the jumps. Minimum eccentric force and peak concentric force were calculated concurrently for countermovement jumps and peak landing forces were calculated concurrently for drop jumps. The results showed moderate to low levels of agreement in forces and a consistent systematic bias between the results from the force platform and accelerometer. However, good agreement between the accelerometer and force platform was observed during the eccentric phase of the countermovement jump.