Synchronisation and Differentiation: Two Stages of Coordinative Structure

While motor skill acquisition process is regarded as development of coordination, typically regarded as synchronisation among joint movements, we found another phenomenon which we call differentiation as a consequence of synchronisation. The synchronised movement established is decomposed into several sections or modulated to be executed on different timings without breaking the coordination among them, resulting in the gain of efficiency or flexibility. In the acquisition of skills, the coordinative structure thus goes through two stages: synchronisation and differentiation. We verify in this paper our observation through our experiments and dynamical analysis of the kneading of ceramic art and playing the shaker in samba

Global Dynamics: a new concept for design of dynamical behavior

The global dynamics, a novel concept for design of human/humanoid behavior is proposed. The principle of this concept is to exploit the body dynamics and apply control input only where it is necessary. Within the phase space of the body dynamics, there are many stable and unstable mani-folds coexist. Then if we analysed its structure and obtained a map in sufficient resolution, it may be possible to realise a motion by exploiting stable regions for reducing control input and unstable regions for switching between stable regions. Also, we expect an emergence of symbols within the dynamics, as the series of points where control input should be adopted. This feature realises higher level description and makes adaptation behavior easier. We are studying from two aspects, the motion capture experiment and dynamical simulation of simple elastic robot. The former supports that above assumption and the latter supports the exploiting the dynamical stability is useful

Non-traumatic Atypical Peri-implant Femoral Fracture at the Distal Screw after Short Femoral Nail Fixation for a Pertrochanteric Fracture

This is the second report of an atypical peri-implant femoral fracture occurring at the distal screw after intramedullary nail fixation of a pertrochanteric fracture. A 94-year-old Japanese female with a 5-year history of alendronate intake presented with prodromal pain in her right thigh after intramedullary nail fixation. Plain radiographs showed an incomplete noncomminuted transverse fracture at the distal screw, suggesting an atypical peri-implant femoral fracture. The pathogenesis of an atypical peri-implant femoral fracture could be a combined systemic bone metabolism disorder and repetitive overloading at the screw, similar to the pathogenesis of an atypical periprosthetic femoral fracture around stem implantation