Soft tissue motion during impact
This research aims to look at violent impacts and the kinetics of such impacts with a view to their potential to cause injury. In these cases non-rigid body motion is obvious and contributes to the overall injury potential and patterns. As a first step the effects that incorporating the motion of the soft tissue of a body segment relative to each limb segment would have on the gross kinetics of the whole system via a wobbling mass model was examined. To this end, a combination of tissue mechanical properties, in vivo soft tissue motion, and behaviour of wobbling mass models needed to be studied. Measurements were taken of the soft tissue of body segments while they underwent impacts with different muscular tensions. An array of 28 surface markers was used to examine the magnitude and frequency content of the marker motion. A 2-D wobbling mass model was developed to simulate landing from a drop. Subject specific anthropometric parameters were calculated for both the rigid links and the wobbling masses. Magnitude and frequency response of the soft tissue of the subject to impulsive loading was measured and used as a control for the wobbling mass motion. The model successfully reproduced the vertical ground reaction force for the first 80 ms of the landing and demonstrated a marked decrease in joint reaction forces and torques over a rigid body model. When examining human impacts the influence of intra-segmental soft tissue motion should not be ignored as it significantly changes the kinetics of the system. The selection of the human-environment interface needs to be carefully chosen in light of the model that is used so as not to reproduce or exclude force-producing elements.
Publications
- Pain, M.T.G. and Tsui, F and Cove, S., 2008. In vivo determination of the effect of shoulder pads on tackling forces in rugby, Journal of Sports Sciences, 26 (8), 75 – 82.
- Challis, J.H. and Pain, M.T.G. 2008. Soft tissue motion influences skeletal loads during impacts. Exercise and Sports Science Reviews, 36 (2), 71-75.
- Pain, M.T.G. and Challis, J.H. 2006. The influence of soft tissue movement on ground reaction forces, joint torques and joint reaction forces in drop landings. Journal of Biomechanics 39, 119-124.
- Pain, M.T.G. and Challis, J.H. 2004. Wobbling mass influence on impact ground reaction forces: a simulation model sensitivity analysis. Journal of Applied Biomechanics 20, 309-316.
- Pain, M.T.G. and Challis, J.H. 2002. Soft tissue motion during impacts: their potential contribution to energy dissipation. Journal of Applied Biomechanics 18, 231-242.
- Pain, M.T. and Challis, J.H. 2001. The role of the heel pad and shank soft tissue during impacts: A further resolution of a paradox. Journal of Biomechanics 343, 327-333.
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