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Paolo De Leva, P.e. Institute,rome - Sport Biom.
05-28-1993, 04:31 AM
Regarding the expression "contact forces", suggested by some
subscribers as a name for non-muscular joint forces (Hinrichs' F2),
I think it does not convey the right concept, because of two reasons:
1) If you think (as I do) that "contact" means zero distance
between two separate objects (underlining SEPARATE), then only
bone-on-bone forces are "contact forces"> And since bone-on-bone forces
are just a component of the non-muscular joint forces, then the name
in inadequate.
2) If you think that contact does not involve only separate objects,
but also two ideal surfaces within a single body, defined by a
plane passing through it,
then also ligament forces are included (and that's what we want), but
unfortunately, muscle forces are not excluded (and that's not what we
want).

In conclusion, whatever is the meaning of the word "contact",
it doesn't fit with the concept we need to express.

I am very happy that my answer to Rick's request provoked
such a lively and interesting debate. I also received private replies,
and I'll try to convince those who sent me those messages to post a
copy to the biomch-l list.

With warmest regards,

Paolo de Leva
Istituto Superiore di Educazione Fisica
Biomechanics Lab
P. Lauro De Bosis, 6
00194 ROME
ITALY

Tel: 39-6-5743523
FAX: 39-6-3613065

e-mail address: DELEVA@RISCcics.ing.uniRoma1.IT