233409 Bullies, 3876 online  
  • Register
Our Sponsors:

Results 431 to 440 of 486
Page 44 of 49 FirstFirst ... 344041424344 45464748 ... LastLast
Sponsored Links Spacer Image
  1. mkornecki is offline

    Registered Member

    Join Date
    Jun 2009
    Location
    MD
    Posts
    36

    Posted On:
    6/15/2009 2:00pm


     Style: Bjj

    --
    Hell yeah! Hell no!
    Quote Originally Posted by SifuJason View Post
    I can't speak to horse jockeys or the anthropological studies, other than making assumptions based on my theories, so I shall refrain.

    As for the papers, I can try and regurgitate more later, but the abstracts are sufficiently telling, and don't simply focus on initial bone growth (especially the dentistry one). The net conclusion from these and the thousand other studies I found talking about compressive forces and bones is that both compressive and tensile forces affect bone growth and remodeling (remodeling and growth being very, very similar processes in bone tissue).
    Wait a minute. We're talking about an increase in bone density, not just mass.

    You're saying you read thousands of artilces? Well, a huge bunch of the hits I received were about analytical models and/or simulations. Those certainly don't have much to say about reality.

    Quote Originally Posted by SifuJason View Post
    I can't say which is more important without doing a lot of research, and I am not sure if it matters for this discussion, since both are significantly important. Gravity, as War Wheel pointed out, may provide some clues, and I am inclined to agree with his assessment.
    I'm not sure what his assessment is. I pointed out that gravity provides loads that provides tensile strains on muscles and bone. Do you disagree with this?

    Certainly astronauts exercise to prevent bone loss in outer space. I.E. they provide tensile loads on muscles and bone. They do not put themselves in a vice and squeeze.
  2. mkornecki is offline

    Registered Member

    Join Date
    Jun 2009
    Location
    MD
    Posts
    36

    Posted On:
    6/15/2009 2:04pm


     Style: Bjj

    --
    Hell yeah! Hell no!
    Quote Originally Posted by War Wheel View Post
    I just read the paper. The study only looked at adolescent girls. I would argue that the bone remodeling in a growing person precludes any (or most) adaptive changes from stress, and would probably mask any effect one might see in full grown adults.
    The fact that they matched participants in age, removes such an argument.

    They didn't compare kids to old people or anorexics to fatties or midgets to basketball players. They matched participants in age,weight, height, to remove such variables.
  3. Matt Phillips is online now
    Matt Phillips's Avatar

    NOTE TO SELF - MOAR GRAPPLE - GET A NORMAL HAIR CUT - REPEAT

    Join Date
    May 2002
    Location
    Bahstun
    Posts
    9,756

    Posted On:
    6/15/2009 2:06pm

    supporting member
     Style: Submission Grappling

    --
    Hell yeah! Hell no!
    Quote Originally Posted by mkornecki View Post
    The fact that they matched participants in age, removes such an argument.

    They didn't compare kids to old people or anorexics to fatties or midgets to basketball players. They matched participants in age,weight, height, to remove such variables.
    I got that. My point was that the bone remodeling machinery will be maxed out while the bone is actually still growing to its mature size.
    Now darkness comes; you don't know if the whales are coming. - Royce Gracie


    KosherKickboxer has t3h r34l chi sao

    In De Janerio, in blackest night,
    Luta Livre flees the fight,
    Behold Maeda's sacred tights;
    Beware my power... Blue Lantern's light!
  4. mkornecki is offline

    Registered Member

    Join Date
    Jun 2009
    Location
    MD
    Posts
    36

    Posted On:
    6/15/2009 2:29pm


     Style: Bjj

    --
    Hell yeah! Hell no!
    Quote Originally Posted by War Wheel View Post
    I got that. My point was that the bone remodeling machinery will be maxed out while the bone is actually still growing to its mature size.
    Yes, but that systematic bias should be removed by age matching.

    It would be nice if they did a study on all age groups etc, but perhaps the other variables (weight) are harder to control at advanced ages. or maybe they just worked with the group they had available.

    But regardless, you have to admit that the fact that jockeys do not have a demonstrably increased bone density is enough to raise a few eyebrows.

    IP practictioners (external) perform feats far greater than the average human. It seems to me that if the these extreme benefits were to be primarily attributable to an increase in bone density, then the bone density increase would likewise have to be extremely significant. Such a variation would be very noticeable to even a casual x-ray, I believe.

    I don't think that a .1% increase would do it.

    Additionally, why arent we persuing whether or not the bones in the forearm or wrist increase in density? After all, they receive a compressive force, admittedly less, from any impact that the hand undergoes.
    Last edited by mkornecki; 6/15/2009 2:34pm at .
  5. SifuJason is offline

    Senior Member

    Join Date
    Jan 2007
    Location
    NC
    Posts
    1,354

    Posted On:
    6/15/2009 2:31pm


     Style: WHKD (Kaju), Sub. Grapple

    --
    Hell yeah! Hell no!
    Quote Originally Posted by mkornecki View Post
    Wait a minute. We're talking about an increase in bone density, not just mass.


    I'm not sure what his assessment is. I pointed out that gravity provides loads that provides tensile strains on muscles and bone. Do you disagree with this?
    Yes, we are talking about density, not mass. As for his assessment, it was that gravity exerts compressive, not just tensile forces, which I agree with. Read his post.

    No I have not read thousands of articles. However, there were thousands of articles published on this topic, which leads to my general conclusion that scientists use compressive forces to alter bone remodeling, and thus compressive forces, as well as tensile forces, are involved.
  6. Matt Phillips is online now
    Matt Phillips's Avatar

    NOTE TO SELF - MOAR GRAPPLE - GET A NORMAL HAIR CUT - REPEAT

    Join Date
    May 2002
    Location
    Bahstun
    Posts
    9,756

    Posted On:
    6/15/2009 2:33pm

    supporting member
     Style: Submission Grappling

    --
    Hell yeah! Hell no!
    Quote Originally Posted by mkornecki View Post
    Yes, but that systematic bias should be removed by age matching.
    Yes, on the assumption that some non-growing age groups were represented. Which they are not.
    Now darkness comes; you don't know if the whales are coming. - Royce Gracie


    KosherKickboxer has t3h r34l chi sao

    In De Janerio, in blackest night,
    Luta Livre flees the fight,
    Behold Maeda's sacred tights;
    Beware my power... Blue Lantern's light!
  7. SifuJason is offline

    Senior Member

    Join Date
    Jan 2007
    Location
    NC
    Posts
    1,354

    Posted On:
    6/15/2009 2:34pm


     Style: WHKD (Kaju), Sub. Grapple

    --
    Hell yeah! Hell no!
    Quote Originally Posted by mkornecki View Post
    Yes, but that systematic bias should be removed by age matching.

    It would be nice if they did a study on all age groups etc, but perhaps the other variables (weight) are harder to control at advanced ages. or maybe they just worked with the group they had available.

    But regardless, you have to admit that the fact that jockeys do not have a demonstrably increased bone density is enough to raise a few eyebrows.

    IP practictioners (external) perform feats far greater than the average human. It seems to me that if the these extreme benefits were to be primarily attributable to an increase in bone density, then the bone density increase would likewise have to be extremely significant. Such a variation would be very noticeable to even a casual x-ray, I believe.

    I don't think that a .1% increase would do it.
    It won't be. Developing women aren't ideal for bone studies because of the role estrogen plays in bone growth and density. It's a confounder they can't control for.

    As for jockeys, I am not sure how much impact in force their bones get compared to punching something (see the boxer study War Wheel posted which I notice you are ignoring). You ass has a lot of muscle around it, which may "dull" the impact your bones receive to induce remodeling.
  8. SifuJason is offline

    Senior Member

    Join Date
    Jan 2007
    Location
    NC
    Posts
    1,354

    Posted On:
    6/15/2009 2:35pm


     Style: WHKD (Kaju), Sub. Grapple

    --
    Hell yeah! Hell no!
    Quote Originally Posted by War Wheel View Post
    I think this pretty much settles it:

    Low body fat mass and menstrual irregularities have been associated with
    low bone mineral density (BMD). The aim of this study was to compare the
    relation between BMD, lean body mass, fat mass, physical activity energy
    expenditure (PAEE), and menstrual status in female boxers and in
    physically active females with low (C1) or average (C2) fat mass. Boxers
    (n = 11) and controls (C1, n = 16; C2, n = 17), aged 18-38 years, were
    assessed for BMD and body composition with dual-energy X-ray
    absorptiometry. Menstrual status and PAEE were determined from
    questionnaires. There was no difference in anthropometric measurements
    between boxers and C1 subjects, except that boxers had higher arm lean
    mass. However,both boxers and C1 subjects had a lower percentage of fat
    (p < 0.001) than C2 subjects (boxers, 14.6% +/- 2.0; C1, 15.5% +/- 4.2; C2,
    25.8% +/- 3.4%), and boxers had a higher (p = 0.002) lean body mass index
    (lean body mass/height2,where lean body mass is measured in kilograms and
    height is measured in metres) than C2 subjects. The PAEE of boxers was
    higher (p < 0.007) than that of controls (boxers, 5748 +/- 2284 ; C1, 2966
    +/- 2258 ; C2, 2714 +/- 1722 kcal.week-1). Oligomenorrhea was more common
    in boxers than in C1 and C2 subjects (boxers, 54.6%; C1, 18.8%; C2, 35.3%).
    Arm, leg, and spine BMD were higher (p < 0.008) in boxers than in C1 subjects,
    and arm BMD was higher in boxers than in C2 subjects. BMD Z scores were also
    higher (p < 0.05) in boxers (boxers, 1.1+/- 0.8, C1, 0.1 +/- 0.7; C2: 0.3 +/-
    1.1). High BMD in boxers, despite low fat mass, high PAEE, and an increased
    incidence of oligomenorrhea suggest that boxing has a positive effect on BMD.
    That pretty much settles it for me. Do you have a link so I can get the full article?
  9. mkornecki is offline

    Registered Member

    Join Date
    Jun 2009
    Location
    MD
    Posts
    36

    Posted On:
    6/15/2009 2:36pm


     Style: Bjj

    --
    Hell yeah! Hell no!
    Quote Originally Posted by SifuJason View Post
    Yes, we are talking about density, not mass. As for his assessment, it was that gravity exerts compressive, not just tensile forces, which I agree with. Read his post.
    No studies have been produced that show an increase in density.

    Quote Originally Posted by SifuJason View Post
    YesNo I have not read thousands of articles. However, there were thousands of articles published on this topic, which leads to my general conclusion that scientists use compressive forces to alter bone remodeling, and thus compressive forces, as well as tensile forces, are involved.
    Where's the beef? Or in this case, where's the bone density increase?
  10. mkornecki is offline

    Registered Member

    Join Date
    Jun 2009
    Location
    MD
    Posts
    36

    Posted On:
    6/15/2009 2:40pm


     Style: Bjj

    --
    Hell yeah! Hell no!
    Quote Originally Posted by War Wheel View Post
    Yes, on the assumption that some non-growing age groups were represented. Which they are not.
    What? There was no such assumption.

    They matched the participants in age weight and height to remove external factors. Statistical averaging would smooth out the effect of bias in any single data point.
Page 44 of 49 FirstFirst ... 344041424344 45464748 ... LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Powered by vBulletin™© contact@vbulletin.com vBulletin Solutions, Inc. 2011 All rights reserved.