Inverse dynamics on rock climbing with and without measurement of contact forces
Résumé
Rock climbing involves complex interactions of the body with the environment. It represents an interesting problem in Biomechanics as multiple contacts in the locomotion task makes it an underconstrained problem. In this study we are interested in evaluating how a climber transfers weight through the holds. The motivation of this study is also technical as we are developing an inverse dynamics method that automatically estimates in 3D, not only the usual torques at joint angles, but also the wrenches at contacts. An artificial climbing wall has been equipped with force and torque sensors at six holds for short performance along a 2.5 m height course. Six subjects have been studied on various hold configurations. Kinematics data of the whole body have been recorded with an optical marker-based system (Optitrack). We use the inverse kinematics software of this system to deliver trajectories for joint angles. We compare the results for force contact estimation of our inverse dynamics method with ground-truth measurement from the sensors on the wall. Once contacts are known, torques at joint angles can be deduced. We also compare the results of our method for torque estimation at joints with results from the OpenSim software. In order to complete the validation, we plan to compare these results with EMG measurement of corresponding muscles.