Justin,
Compressive stress can increase bone strength in normal bone that remodels correctly. If it is too high it can deform/fail the bone, if it is too low (including 0 as in space labs; and the opposite direction as in tension) the bone strength can decrease. It is my understanding that typically the forces applied by muscles are much greater than any external weight (with the possible exception of power lifters), as example consider that walking can produce ground reaction forces several times body weight versus most people who will typically weight train a loads less than their own body weight.
People with osteoporosis obviously do not have normal bone. I would question the benefit of your program design given your basic questions and think you may be opening yourself up to some serious liability issues here, not to mention that you could seriously hurt someone following a program that fails to correctly negotiate the complexities of these issues.
Bryan Kirking
Research Engineer
Department of Orthopedic Surgery
Baylor College of Medicine
Houston, Texas
-----Original Message-----
From: Justin Keogh NHS [SMTP:Justin.Keogh@nhs.gu.edu.au]
Sent: Thursday, June 25, 1998 10:47 PM
To: BIOMCH-L@NIC.SURFNET.NL
Subject: osteoporosis and resistance training
Hi,
I am currently designing some resistance training programs for some
clients who suffer from mild to moderate degrees of osteoporosis. I
undertsnd that like muscle, bone tissue responds to the loads imposed
on it by getting bigger (denser) and/or stronger. Do these "loads"
have to be a compressive force applied through the bones eg during a
squat the vertebrae is compressed by the weight of the barbell and
upper body; or is it just a fact of the contracting muscles placing
stress (primarily a tension force) on the bones comprising the
articulating joint?
Yesterday on a science chat show on a national radio station, some
doctor (I think) rang in and said that compressive forces stimulate
osteoblast activity and hence increase the laying down of new bone
tissue, while tension forces will increase osteoclast activity and
hence breakdown bone tissue.
If these statements are correct, then exercises such as squats,
pushups and bench presses would be advisable for osteoporosis
sufferers due to the compressive loading of the bones, while chinups,
lat pulldowns and seated rows would be inadvisable due to the tension
forces through the bones.
I would appreciate any comments on these statements, as well as any
references or practical experience anyone has had in this area.
Yours sincerely,
Justin Keogh.
__________________________________________________
Justin Keogh BHMS (Hons)
justin.keogh@nhs.gu.edu.au
Griffith University, Gold Coast
School of Exercise Science
Room 3.32 NHS
07 5594 8941 (W) 0419 714 921 (M)
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Compressive stress can increase bone strength in normal bone that remodels correctly. If it is too high it can deform/fail the bone, if it is too low (including 0 as in space labs; and the opposite direction as in tension) the bone strength can decrease. It is my understanding that typically the forces applied by muscles are much greater than any external weight (with the possible exception of power lifters), as example consider that walking can produce ground reaction forces several times body weight versus most people who will typically weight train a loads less than their own body weight.
People with osteoporosis obviously do not have normal bone. I would question the benefit of your program design given your basic questions and think you may be opening yourself up to some serious liability issues here, not to mention that you could seriously hurt someone following a program that fails to correctly negotiate the complexities of these issues.
Bryan Kirking
Research Engineer
Department of Orthopedic Surgery
Baylor College of Medicine
Houston, Texas
-----Original Message-----
From: Justin Keogh NHS [SMTP:Justin.Keogh@nhs.gu.edu.au]
Sent: Thursday, June 25, 1998 10:47 PM
To: BIOMCH-L@NIC.SURFNET.NL
Subject: osteoporosis and resistance training
Hi,
I am currently designing some resistance training programs for some
clients who suffer from mild to moderate degrees of osteoporosis. I
undertsnd that like muscle, bone tissue responds to the loads imposed
on it by getting bigger (denser) and/or stronger. Do these "loads"
have to be a compressive force applied through the bones eg during a
squat the vertebrae is compressed by the weight of the barbell and
upper body; or is it just a fact of the contracting muscles placing
stress (primarily a tension force) on the bones comprising the
articulating joint?
Yesterday on a science chat show on a national radio station, some
doctor (I think) rang in and said that compressive forces stimulate
osteoblast activity and hence increase the laying down of new bone
tissue, while tension forces will increase osteoclast activity and
hence breakdown bone tissue.
If these statements are correct, then exercises such as squats,
pushups and bench presses would be advisable for osteoporosis
sufferers due to the compressive loading of the bones, while chinups,
lat pulldowns and seated rows would be inadvisable due to the tension
forces through the bones.
I would appreciate any comments on these statements, as well as any
references or practical experience anyone has had in this area.
Yours sincerely,
Justin Keogh.
__________________________________________________
Justin Keogh BHMS (Hons)
justin.keogh@nhs.gu.edu.au
Griffith University, Gold Coast
School of Exercise Science
Room 3.32 NHS
07 5594 8941 (W) 0419 714 921 (M)
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