Rocker outsole shoes and margin of stability during walking: A preliminary study

Rocker outsole shoes are commonly prescribed to diabetic patients to redistribute peak plantar pressures at high risk areas such as forefoot thereby decreasing risks of plantar ulceration. However, there are evidences of postural destabilizing effect of the rocker outsole shoes. Patients with diabetes, particularly those suffering from neuropathy, are at a higher risk of falling. Then, beside primary role of rocker outsole in offloading, it is essential to explore the effect of the rocker outsole on postural stability of these patients. The smaller base of support (BOS) of the rocker outsoles due to their specific geometry has been previously mentioned as a threat to postural stability. Margin of stability (MOS) appeared to be an appropriate method for measuring postural stability during walking by considering the dynamicity of BOS in its equation. MOS is defined as the distance between the velocity adjusted position of the centre of mass (COM) and the boundaries of the BOS which constantly changes during walking. Then, this study proposes how we can use MOS concept to investigate the impact of the rocker outsoles on dynamic stability. In this study the kinematic data from a single subject with diabetic neuropathy was used to explain the efficiency of the methodology. Conclusive results are expected after carrying out systematic tests using a statistically representative sample size.