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I believe you should focus your attention on what happens in the flexed
leg. There, the extensor muscles can relax completely, and the load on the
foot can be decreased to almost zero.
Since almost all of the static load is on the other leg, I believe in
the hip and knee extensors on that "overloaded" side there must be a larger
postural activity than in the standard symmetrical standing posture. There
must also be much larger bone-on-bone forces at the joints. There might also
be activity in the hip adductors, together with ligament stretching. These
are all drawbacks.
In my opinion, there can't be any reason for overloading one leg so much
except that the extensor muscles on the other side can relax completely and
bone-on-bone forces can be almost zeroed.
Notice that in PROLONGED SYMMETRICAL STANDING the isometric postural
contraction may hinder blood flux, particularly venous return. Also,
bone-on-bone forces can reduce blood flux in the joint cartilages. Complete
relaxation on one side can help to reduce idrodinamic and idrostatic blood
pressure in the veins.
I practice free climbing. Often, when you hold your weight with both
hands on a rock and feel fatigued, it is convenient to leave one hand and
hold yourself for a while with the other hand only, so that the finger
flexors in the free limb can relax and recover from fatigue, due to larger
oxigenated blood flux with consequent removal of CO2 and lactic acid...
Weird, but it seems to work.
Regards,
Paolo de LEVA
University Institute of Motor Sciences
Sport Biomechanics
P. Lauro De Bosis, 6
00194 ROME - ITALY
Telephone: (39) 06.367.33.522
FAX/AM: (39) 06.367.33.517
FAX: (39) 06.36.00.31.99
Home:
Tel./FAX/AM: (39) 06.336.10.218
----- Original Message -----
From: "Inma"
To:
Sent: Tuesday, May 06, 2003 1:55 PM
Subject: question about the contraposto pose...
Hi all,
Maybe someone know the answer to a question I have. If you know someone
that could help me, please tell me.
I would like to know why people adopt the contraposto pose (like "David of
Michelangelo") while standing.
That is, a flexed leg and the body weight supported by the other leg.
I want to know it because I'm interested in generate postures automatically
and a standing person, sooner or later, will converge to this posture. I
would like the reason
that drive people to adopt this posture. In fact, my questions are:
do we adopt this posture due to we are trying to find passive torque in the
limit of the hip joint?
In other words, Is it related to passive elastic joint moments obtained in
the joint limit?
I've read that passive elastic joint moment is produced only by a assisted
movement (a second person
forces the movement). Is it true?
thanks in advance,
Inmaculada (inma@aut.uah.es)
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leg. There, the extensor muscles can relax completely, and the load on the
foot can be decreased to almost zero.
Since almost all of the static load is on the other leg, I believe in
the hip and knee extensors on that "overloaded" side there must be a larger
postural activity than in the standard symmetrical standing posture. There
must also be much larger bone-on-bone forces at the joints. There might also
be activity in the hip adductors, together with ligament stretching. These
are all drawbacks.
In my opinion, there can't be any reason for overloading one leg so much
except that the extensor muscles on the other side can relax completely and
bone-on-bone forces can be almost zeroed.
Notice that in PROLONGED SYMMETRICAL STANDING the isometric postural
contraction may hinder blood flux, particularly venous return. Also,
bone-on-bone forces can reduce blood flux in the joint cartilages. Complete
relaxation on one side can help to reduce idrodinamic and idrostatic blood
pressure in the veins.
I practice free climbing. Often, when you hold your weight with both
hands on a rock and feel fatigued, it is convenient to leave one hand and
hold yourself for a while with the other hand only, so that the finger
flexors in the free limb can relax and recover from fatigue, due to larger
oxigenated blood flux with consequent removal of CO2 and lactic acid...
Weird, but it seems to work.
Regards,
Paolo de LEVA
University Institute of Motor Sciences
Sport Biomechanics
P. Lauro De Bosis, 6
00194 ROME - ITALY
Telephone: (39) 06.367.33.522
FAX/AM: (39) 06.367.33.517
FAX: (39) 06.36.00.31.99
Home:
Tel./FAX/AM: (39) 06.336.10.218
----- Original Message -----
From: "Inma"
To:
Sent: Tuesday, May 06, 2003 1:55 PM
Subject: question about the contraposto pose...
Hi all,
Maybe someone know the answer to a question I have. If you know someone
that could help me, please tell me.
I would like to know why people adopt the contraposto pose (like "David of
Michelangelo") while standing.
That is, a flexed leg and the body weight supported by the other leg.
I want to know it because I'm interested in generate postures automatically
and a standing person, sooner or later, will converge to this posture. I
would like the reason
that drive people to adopt this posture. In fact, my questions are:
do we adopt this posture due to we are trying to find passive torque in the
limit of the hip joint?
In other words, Is it related to passive elastic joint moments obtained in
the joint limit?
I've read that passive elastic joint moment is produced only by a assisted
movement (a second person
forces the movement). Is it true?
thanks in advance,
Inmaculada (inma@aut.uah.es)
---------------------------------------------------------------
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For information and archives: http://isb.ri.ccf.org/biomch-l
---------------------------------------------------------------
---------------------------------------------------------------
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For information and archives: http://isb.ri.ccf.org/biomch-l
---------------------------------------------------------------