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Fitness Theory and Practice. CrossFit's rationale & foundations. Who is fit? What is fitness?

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Old 09-16-2009, 09:59 AM   #1
Peter Nathan
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Exercise intensity and cognitive function

A recent article(http://well.blogs.nytimes.com/2009/0...-smarter/)(wfs) in the N.Y.Times reviews an experiment in which two groups of mice are allowed either to run on a wheel at a self selected pace, or are forced to run at a pace selected by the investigators. The two groups are then measured in tests of thier learning skills and memory. The scientists observed that the mice who were forced to run faster showed better cognitive function, and had more extensive changes in brain structure. Although the investigators compared easy rodent wheel running to forced minitreadmill running, they concluded that different types of exercise induce different changes in brain structure. A more appropriate conclusion would be that the more intense the exercise bout, the more profound the cognitive adaptations.

The article cites another experiment (The Effect of Acute Aerobic and Resistive Exercise on Working Memory) published in the April '09 of Medicine and Science in sports and Exercise, in which three groups of college students are given a cognitive function test after either aerobic exercise, weight training, or quiet rest. The group that performed aerobic exercise (jogging) out-performed the other groups. Thus, the scientists concluded that aerobic exercise induces changes in cognitive function, while weight training does not.

Why do I have a problem with this? Lets look at the exercise protocols. The aerobic group ran on a treadmill for 30 minutes at 60 - 70% of VO2 Max. This would be a moderate intensity workout. The weight training group performed 3 sets of 8 to 12 reps at ~ 80% of their 1 RM for each of the seven major muscle groups on a Body-Solid EXM3000S multistation gym. They were given a one minute rest between sets and a minute and a half rest between exercises. So, these untrained college students followed a isolated body part protocol while seated on a machine. They completed a total of seven minutes of seated exercise (30 mins minus 23 minutes rest). While this may be what most people think of as weight training, it is far from what a crossfitter would term intense exercise. If, as the first study implied, intensity is the key to inducing cognitive changes, the second study is seriously flawed.

More interesting would be a study of cognitive function after Fran, Diane, Grace, etc. Or, how about comparing a 4 X 400 meter workout with Fran? Perhaps we could compare a 4 X 800 meter workout to a 3200 meter jog? It seems to me that differences in cognitive function after exercise may depend more on intensity of effort than on artificial distinctions between exercise types.
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Old 09-16-2009, 10:11 AM   #2
Katherine Derbyshire
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Re: Exercise intensity and cognitive function

It would be interesting to do the same test on people who did olympic lifting or gymnastics. Is the benefit from the intensity of exercise, from the cognitive demands of the exercise itself, from the metabolic effects, or some combination of both?

My money is on a combination:
* intense exercise releases a flood of endorphins and other happy brain chemicals with well-known cognitive benefits
* exercise that demands agility and coordination improves proprioception and spatial awareness. Would make sense for that to improve performance on purely cognitive tasks involving spatial relationships.
* aerobic exercise promotes efficient functioning of the cardiovascular system, which would tend to improve the flow of blood and oxygen to the brain.

Katherine
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Old 09-16-2009, 10:15 AM   #3
Tony Black
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Re: Exercise intensity and cognitive function

Quote:
Originally Posted by Peter Nathan View Post
Why do I have a problem with this? Lets look at the exercise protocols. The aerobic group ran on a treadmill for 30 minutes at 60 - 70% of VO2 Max. This would be a moderate intensity workout. The weight training group performed 3 sets of 8 to 12 reps at ~ 80% of their 1 RM for each of the seven major muscle groups on a Body-Solid EXM3000S multistation gym. They were given a one minute rest between sets and a minute and a half rest between exercises. So, these untrained college students followed a isolated body part protocol while seated on a machine. They completed a total of seven minutes of seated exercise (30 mins minus 23 minutes rest). While this may be what most people think of as weight training, it is far from what a crossfitter would term intense exercise. If, as the first study implied, intensity is the key to inducing cognitive changes, the second study is seriously flawed.
Id tend to think your right on that one....

Quote:
More interesting would be a study of cognitive function after Fran, Diane, Grace, etc. Or, how about comparing a 4 X 400 meter workout with Fran? Perhaps we could compare a 4 X 800 meter workout to a 3200 meter jog? It seems to me that differences in cognitive function after exercise may depend more on intensity of effort than on artificial distinctions between exercise types.
Hahah i have trouble drooling after Fran!

But id be very interested in hearing results of said test - also interesting to hear the results for seasoned crossfitters - intermediates and newbies....
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Old 09-16-2009, 12:15 PM   #4
John Harris
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Re: Exercise intensity and cognitive function

Below quote is from page 4 of this link: Link deleted. You must indicate whether your links are Work and Family Safe (WFS)

Quote:
Physical Fitness Helps Maintain Cognitive Function
Physically fit adults are more likely to maintain their level of cognitive
function as they get older, compared with adults who are less
fit, a study in the Journal of the American Geriatrics Society shows. The
study findings suggest, but do not prove, that regular physical activity
helps prevent dementia.
Investigators studied the aerobic capacity of 349 people, age 55
and older, who were free frommajor diseases and cognitive impairment.
At the beginning of the study, the volunteers underwent a
treadmill exercise test to determine their peak oxygen consumption,
the length of time they could exercise, and how efficiently
they used oxygen. Cognitive function was tested at the study’s beginning
and six years later.
People with the highest levels of aerobic capacity at the study’s
onset were the ones most likely to maintain their initial cognitive
scores when retested six years later. Those who performed poorly
on the treadmill test were more likely to have experienced cognitive
decline over the six years.
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Old 09-16-2009, 05:02 PM   #5
Dave Winchester
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Re: Exercise intensity and cognitive function

Quote:
Originally Posted by Peter Nathan View Post
A recent article(http://well.blogs.nytimes.com/2009/0...-smarter/)(wfs) ... they concluded that different types of exercise induce different changes in brain structure. A more appropriate conclusion would be that the more intense the exercise bout, the more profound the cognitive adaptations.
Besides the fact that mice were used, the relationship between intensity and cognitive function probably isn't linear.

Quote:
If, as the first study implied, intensity is the key to inducing cognitive changes, the second study is seriously flawed.
Given the context it might not be because that weight training session was appears less intense than the aerobic session.

I agree that the conclusions are flawed (if it the wording was indeed that general).
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