Measuring Lower Limb Loading during Dynamic Sporting Actions: Reducing Errors from Soft Tissue Interference and Filtering

When determining lower limb loading (LLL) sources of error include the vibration of kinematic marker plates and how the motion and force data are digitally filtered. This study examined LLL during dynamic actions with reduced marker vibration using a tibial plate (TP) and two different levels of filtering severity (15 Hz and 35 Hz cut-offs). The increase of the filter cut-off frequency for the TP led to significantly higher LLL compared to the normally used soft tissue mounted plate. Especially for a cut task, the TP was able to track the high frequency movement components and a higher filter cut-off frequency allowed these to be maintained in the dataset. This suggests that the peak magnitudes of variables linked to the risk of lower limb injury can be underestimated in the literature and there is likely to be a lack of sensitivity in determining ‘at risk’ individuals.