1 2 Energy - related optimal control accounts for gravitational load : comparing 3 shoulder , elbow and wrist rotations . 4 5 6 Abbreviated title : Gravity force integration in movement planning
نویسندگان
چکیده
25 We permanently deal with gravity force. Experimental evidences revealed that moving 26 against gravity strongly differs from moving along the gravity vector. This directional 27 asymmetry has been attributed to an optimal planning process that optimizes gravity force 28 effects in order to minimize energy. Yet, only few studies have considered the case of vertical 29 movements in the context of optimal control. What kind of cost is better suited to explain 30 kinematic patterns in the vertical plane? Here, we aimed to further understand how the CNS 31 plans and control vertical arm movements. Our reasoning was the following: if the CNS 32 optimizes gravity mechanical effects on the moving limbs, kinematic patterns should change 33 according to the direction and the magnitude of the gravity torque being encountered in the 34 motion. Ten subjects carried-out single joint movements, i.e., rotation around the shoulder 35 (whole arm), elbow (forearm) and wrist (hand) joints, in the vertical plane. Joint kinematics 36 were analysed and compared to various theoretical optimal models predictions (minimum 37 absolute work-jerk; jerk; torque change; variance). We found both direction-dependent and 38 joint-dependent variations in several kinematic parameters. Notably, directional asymmetries 39 decreased according to a proximo-distal gradient. Numerical simulations revealed that our 40 experimental findings could be attributed to an optimal motor planning (minimum absolute 41 work-jerk) that integrates the direction and the magnitude of gravity torque and minimizes the 42 absolute work of forces (energy related cost) around each joint. Present results support the 43 general idea that the CNS implements optimal solutions according to the dynamical context of 44 the action. 45 46
منابع مشابه
Energy-related optimal control accounts for gravitational load: comparing shoulder, elbow, and wrist rotations.
We permanently deal with gravity force. Experimental evidences revealed that moving against gravity strongly differs from moving along the gravity vector. This directional asymmetry has been attributed to an optimal planning process that optimizes gravity force effects to minimize energy. Yet, only few studies have considered the case of vertical movements in the context of optimal control. Wha...
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