Dear Rebecca,

in my opinion the normalization of the free moment depends on the purpose of
your analysis, that is the reason why the normalization is necessary. If it
is necessary for comparing the dynamics of or collecting data from different
subjects, then the solution of using both Weight and Height should be
adopted, like in Benedetti MG, 1997 doi: 10.1016/S0268-0033(97)00041-7

Again, if the purpose is to compare your results with some reference graphs
provided by other authors, their technique of normalization must be adopted
to perform the visual comparison.

I want to underline that the problem you submitted still exists for another
aspect related to dynamics: what about the normalization of joint powers?
Apparently it is far to be consistent among the researchers.


Pietro Garofalo M. Eng.
Ph.D. Candidate
INAIL Prosthesis Centre - Research Area
Via Rabuina 14
40054 Vigorso di Budrio, Italy
Ph: +39 0516936602
Mobile: +39 3934144631
Mobile in Holland: +31 0621294335

2009/7/15 Rebecca Fellin

> Free moment, or the torsional loading between the foot and the ground, has
> been studied on a limited basis for gait analyses. Cavanagh and Holden
> proposed normalizing free moment to bodyweight (BW) and height in their 1991
> paper about free moment. For joint moments, it is generally accepted that
> they need to be normalized to account for differences in height, through
> overall height or length of a particular segment. However, as free moment is
> in essence a moment without a reference segment, perhaps it would be better
> to only normalize it to BW.
> A cited reference search on Web of Science turned up 16 citations of
> Cavanagh and Holden, 1991. Of those, 12 papers calculated free moment for
> activities ranging from standing to running and jumping. Six normalized to
> BW and height as Cavanagh and Holden did. Two normalized to BW and leg
> length, two did not normalize, and two did not state their normalization
> technique.
> I am curious what thoughts the biomechanics community has about appropriate
> normalization parameters for free moment. I will post a summary of replies.
> Rebecca Fellin, MS
> ASB Student Representative
> Research Assistant
> Biomechanics and Movement Science
> University of Delaware
> Newark, DE 19716
> W:302-831-4646
> ---------------------------------------------------------------
> Information about BIOMCH-L:
> Archives:
> ---------------------------------------------------------------