View Full Version : moments of joints

Rosemary Reid
06-30-1997, 12:18 AM
Dear Biomch-L,
Ref: Capozzo et al. (1975) A General Computing method for the analysis of
human locomotion. Journal of Biomechanics Vol. 8 pp 307-320

I have been trying to recreate the graphs shown in this paper of the moments
about the ankle, knee and hip over time using the equations in the paper.
However the graphs I have are not the same as in the paper. The main factor
in the ankle moment equation is the ground reaction force, in the knee it is
the ankle moment and for the hip the knee moment. But in the equations
printed there is a typing inconsistency wherein the arithmetic symbols don't
match up. If the Rz (ground reaction force) value is negative then the
values for the ankle moments are correct. In both the hip and knee equations
the graphs also don't match unless the ankle moment (for the knee) and the
knee moments for the hip are also negative. Having checked and rechecked
the values for the constants such as the thigh mass then the only other
option is the differentiation of the joints angles which I have defined as
the difference in the angle theta i+1 - theta i over the differnece in time.

Does anybody out there know the present whereabouts of the authors or
whether or not my equation for differentiation of the angles is usable and
lastly whether or not the changes in the equations would be fair?

Thank you in advance for your help and I look forward to any replies.

Yours sincerely,

Rosemary Reid
Department of Mechanical Engineering
Loughborough University
LE11 3TU
tel 01509 223748