07 February 2012

"Use it or lose it" - updated

Relatively few researchers have looked at how the muscles of masters athletes – individuals who exercise routinely – decline, or don’t, as they get older. To look at this cross-section of society, Wroblewski and his team took muscle and body composition measurements of 40 high-level recreational athletes.

The subjects, 20 men and 20 women, ranged in age from 40 to 81 years and practiced their sport, primarily running, biking and/or swimming, four to five times per week.

The results showed that mid-thigh muscle mass and lean mass did not increase with age. But it didn’t decrease either. And, the older athletes seemed to maintain their muscle mass even though their body fat increased, relative to the younger competitors in the study.

These observations suggest that body fat was accumulating in places other than within the muscles, which is better for maintaining muscle strength. Tests on the subjects’ quads strength also showed that it did not decline with age either.
Source: Wroblewski, A., et. al. Chronic Exercise Preserves Lean Muscle Mass in Masters Athletes. The Physician and Sportsmedicine. Volume: 39, No.3., via Bicycle Lab and Neatorama.


Addendum:  Reader Ran has made an important observation re the above set of images.  The second one - "74 year old and sedentary" - appears to show a shrinking of the muscle mass (and perhaps a lessening of femoral density).  However, a different web page, maintained by the University of Florida Muscle Physiology Laboratory, has this identical image, with the following explanatory caption:
"Cross-sectional T1 weighted MRI of the thighs from an obese elderly subject. Note the high amount of fat (in white) surrounding the small amount of muscle (in dark) due to sarcopenic obesity."
The image of the legs of the sedentary person has been scaled down to match the size of the bracketing images.  The reflex assumption by the viewer is that the sedentary person has a markedly shrunken muscle mass, whereas what he/she may have is a modestly reduced muscle mass surrounded by a large amount of adipose tissue. 

The important data are the actual measurements of the muscle mass (or the muscle cross-sectional area) of the second image.  The abstract of the original article indicates that the study by Wroblewski showed no loss of thigh muscle mass in "masters athletes."  Their study did not include untrained subjects, but rather compares their results to "the common observation that muscle mass and strength decline as a function of aging alone."

I would agree with reader Ran that inclusion of the second image is misleading.

9 comments:

  1. Look at the difference in the wall thickness of the femur as well. It's amazing how much bone you can lose over time if you don't exercise.

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    Replies
    1. I had the same thought about bone loss but there is no scale (nor indication on gender and height) to compare the three pictures (the second one showing smaller but closer bones).

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    2. http://mpl.phhp.ufl.edu/aging/

      I found this page that has the same 2nd image, but labels it as coming from an obese person, so it would be a much thicker leg scaled down to the size of the other two, which explains the thinner looking bones. The difference in muscle is exaggerated by the scaling. The arrangement of those three images is very misleading, and seems deliberately so.

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    3. Thank you, Ran! You're absolutely correct, and I totally agree. I've inserted an addendum in the post, and will bump it to the top of the queue tomorrow morning to update other readers.

      I used to review publications for academic journals, so I appreciate the time you took to search out this information and post your comment.

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  2. Causation v. Correlation. Perhaps one reason the 74 yearold fat guy is not disposed to excersize is because it's uncomfortable with clogged arteries. Hence people prone to that condition are not triathletes and not that the athleticism keeps the arteries clear.

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  3. It's strange that in a scientific paper there wouldn't be an asterisk or key explaining that the second image has been scaled down. Also strange that it would be scaled down at all as well as not showing an image from an obese person of the same age as the first image. I haven't come across any reason for bias but this paper would get me a B in class because of the aformentioned.

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  4. I thought the scale was obvious due to the diameter of the bones? Likewise, fatty's muscle looks like brisket - yuck.

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  5. I think in light of the revelation that the second picture comes from an obese person and is simply scaled down leaves this entry as "flawed" and it should be removed. You've added the addendum but I don't think everybody will scroll down and read it so I would categorize this as "mis-information".

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    Replies
    1. Right. But the post also serves as an instructional item on how appearances can be deceiving and how images can be manipulated to achieve an end. So I'm leaving it up as a teaching tool.

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