Richard Baker

03-16-2000, 02:47 AM

In calculating the total amount of work done on the basis of the movements

of body segments, during gait for example, it is common (Winter 1979,

Pierrynowski 1980, Viswanath 1999) to consider the potential energy, the

translational kinetic energy and the rotational kinetic energy. In

calculating total work done the translational and rotational energy terms

are treated as separate. Is this justified?

It is my understanding that there is just one scalar quantity, kinetic

energy, and that the translational and rotational "components" are simply a

means of calculating this total. Given this surely the total kinetic energy

for each segment should be treated as a single term for the calculation of

total work.

Whilst we are on this subject, there is at least one series of papers which

talks of the forward, lateral and vertical components of translational

kinetic energy (although the use of the terms does not affect the

mathematical analysis). Surely kinetic energy is a scalar and there is no

physical meaning to these "components"?

Am I right? Right, but overly pedantic? Plain wrong?

I'd be interested in anyone's comments.

Richard

Richard Baker PhD

Gait Analysis Service Manager

Musgrave Park Hospital, Stockman's Lane, Belfast, Northern Ireland, BT9 7JB

Tel: +44 2890 669501 ext 2155 or 2849

Fax: +44 2890 382008

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of body segments, during gait for example, it is common (Winter 1979,

Pierrynowski 1980, Viswanath 1999) to consider the potential energy, the

translational kinetic energy and the rotational kinetic energy. In

calculating total work done the translational and rotational energy terms

are treated as separate. Is this justified?

It is my understanding that there is just one scalar quantity, kinetic

energy, and that the translational and rotational "components" are simply a

means of calculating this total. Given this surely the total kinetic energy

for each segment should be treated as a single term for the calculation of

total work.

Whilst we are on this subject, there is at least one series of papers which

talks of the forward, lateral and vertical components of translational

kinetic energy (although the use of the terms does not affect the

mathematical analysis). Surely kinetic energy is a scalar and there is no

physical meaning to these "components"?

Am I right? Right, but overly pedantic? Plain wrong?

I'd be interested in anyone's comments.

Richard

Richard Baker PhD

Gait Analysis Service Manager

Musgrave Park Hospital, Stockman's Lane, Belfast, Northern Ireland, BT9 7JB

Tel: +44 2890 669501 ext 2155 or 2849

Fax: +44 2890 382008

---------------------------------------------------------------

To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl

For information and archives: http://isb.ri.ccf.org/biomch-l

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