Degrees of freedom

[Bruno Straiotto]

Dear Biomech-L,

In our Lab we are discussing how to quantify operational degrees of freedom (DOF) in complex, whole-body movement patterns such as those for someone moving over an obstacle course. Whilst I am aware that a lot of research has been done involving variability in movement patterns, I am wondering whether any members have done about, or know of, a method for defining specific task-related DOF? I would be grateful if anyone could offer opinions/suggestions/idea in approaching this area


Thanks,

Bruno

Lsbu

[Paul S Glazier]

Re: Degrees of freedom

Hi Bruno,

You may find this article to be of use: http://journals.humankinetics.com/Ac...tItem/6162.pdf

Best Regards,

Paul

[Zheng Wang]

Re: Degrees of freedom

Hi Bruno,
Another useful analysis method could be: http://www.sciencedirect.com/science...67945713000997

Regards,

Zheng

[Natalia Dounskaia]

Re: Degrees of freedom

Most existing methods are based on DOF’s kinematics. We argue that DOF’s kinematics is a by-product of control strategies driven by movement dynamics. Multi-joint movements are performed by actively accelerating/decelerating a single (leading) joint and using the mechanical effect of this motion for rotation of the other (trailing) joints. To understand the role of each joint in movement production, we use inverse dynamics equations to compute the active and passive components of the moments at each joint and analyze, for each joint, whether muscle moment contributes to net moment or net moment is mainly generated by passive effects. Some other researchers suggest using the induced acceleration analysis for similar purposes. Both ways allow deciphering the general control strategy and the role of each joint in it. The results are especially amazing for movements with a large number of DOFs because the control often turns out to be very simple, with a single joint/muscle group producing almost entire movement. I have anecdotal evidence for this with respect to alpine skiing. It has turned out to be so simple! Review articles of the theory can be found here:

http://www.ncbi.nlm.nih.gov/pubmed/20871237

http://www.ncbi.nlm.nih.gov/pubmed/16132966

Natalia Dounskaia