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

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Old 03-08-2007, 03:35 AM   #1
John Tuitele
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link to research article is family and work safe.

http://www.medscape.com/viewarticle/506930

This article compares acute and chronic response to resistance exercise when a rest is imposed mid set vs. no rest mid set. Helps to answer the question in my mind about the effect of higher intensity during exercise.
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Old 03-08-2007, 07:45 AM   #2
Matt DeMinico
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Looks like a pretty good article that backs up what CF has been saying, thanks.
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Old 08-25-2007, 07:34 AM   #3
Corey Duvall
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Re: Interesting research article re: exercise intensity. FS/WS link.

This brings up a few good talking points. 1) What role does the For Time stimulus play on the effect of the exercise? The thought comes up once in a while as to whether taking each set to fatigue (if that means you can get 15 out of 21 reps) and then resting and performing the rest of the set, or whether one should perform less than a maximal effort (11 of the 21 reps, then getting the other 10) when perhaps the latter would result in a better time. I have most often gone to full fatigue in each set, rested, then attempted again. Sometimes i don't do that, whether I'm not mentally there or feel my technique would suffer too much. What do others do?

2) The metabolic stresses are not incurred much in the 5RM and below according to the article's sources. What then are the positive effects of working at that intensity? Is it a more neurological change that occurs in this realm; increasing the ability to fire more motor units at once? Perhaps this then carries over to when you're feeling greater fatigue in the higher RM range, you have the ability to fire more motor units and get the last few reps when a majority of your fibers are fatigued? If this is the case, I would then say Crossfit still has it correct: Our specialty is not specializing. Getting the most out of the body. Does anyone know of any sources relating to such ideas, or have any ideas of their own?
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Old 08-25-2007, 09:17 AM   #4
Brandon Oto
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Re: Interesting research article re: exercise intensity. FS/WS link.

That link demands an account login for me. Can you cite the particulars (name, date, researchers, etc) of the study, so I could find it through a database I have access to?
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Old 08-25-2007, 02:49 PM   #5
Steven Low
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Re: Interesting research article re: exercise intensity. FS/WS link.

I can't read it either.

Corey:

1. Resting vs. going all out have their merits. Discussed at least 3x in threads in WOD forum.

2. 5 RM and lower generally tend to be strength repetitions. Here's a nice chart from Rippetoe's Starting Strength that should give you an idea (w/f safe):

http://www.****************.com/files/sample200.pdf
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Old 08-25-2007, 06:41 PM   #6
David Wood
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Re: Interesting research article re: exercise intensity. FS/WS link.

Medscape does require registration, but it's free, and they don't spam you much. They put out a weekly newsletter called "The Business of Medicine" which is both enlightening, and sometimes alarming.

Here is the reference:


From Medicine and Science in Sports and Exercise



The Impact of Metabolic Stress on Hormonal Responses and Muscular Adaptations

Kazushige Goto; Naokata Ishii; Tomohiro Kizuka; Kaoru Takamatsu

Abstract

Purpose: The purpose of this study was to examine the impact of exercise-induced metabolic stress on hormonal responses and chronic muscular adaptations.
Methods: We compared the acute and long-term effects of an NR regimen (no-rest regimen) and those of a WR regimen (regimen with rest period within a set). Twenty-six male subjects were assigned to either the NR ( N = 9), WR ( N = 9), or control (CON, N = 8) groups. The NR regimen consisted of 3-5 sets of 10 repetitions at 10-repetition maximum (RM) with an interset rest period of 1 min (lat pulldown, shoulder press, and bilateral knee extension). In the WR regimen, subjects completed the same protocol as the NR regimen, but took a 30-s rest period at the midpoint of each set of exercises in order to reduce exercise-induced metabolic stress. Acute hormonal responses to both regimens were measured followed by a 12-wk period of resistance training.
Results: Measurements of blood lactate and serum hormone concentrations after the NR and WR regimens showed that the NR regimen induced strong lactate, growth hormone (GH), epinephrine (E), and norepinephrine (NE) responses, whereas the WR regimen did not. Both regimens failed to cause significant changes in testosterone. After 12 wk of resistance training, the NR regimen caused greater increases in 1RM ( P < 0.01), maximal isometric strength ( P < 0.05), and muscular endurance ( P < 0.05) with knee extension than the WR regimen. The NR group showed a marked increase ( P < 0.01) in muscle cross-sectional area, whereas the WR and CON groups did not.
Conclusion: These results suggest that exercise-induced metabolic stress is associated with acute GH, E, and NE responses and chronic muscular adaptations following resistance training.



When you get down to it, this looks like pretty much the quintessential "validation of CrossFit" study . . . the "no rest" group (who still took a 1-minute rest between sets, just didn't rest "within" their sets) were better on pretty much every metic we're interested in than the "with rest" group.

It's not exactly "CrossFit" yet. Still only doing 3 sets of 10. Still using isolation machine exercises. But they're getting there . . .

Last edited by David Wood : 08-25-2007 at 06:46 PM.
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Old 08-25-2007, 06:43 PM   #7
Corey Duvall
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Re: Interesting research article re: exercise intensity. FS/WS link.

I think I decided today during my workout to do the normal WOD's attempting to get as many reps strung together as possible even if it decreases my time. The named WOD's I'll do for time efficiency in order to guage my progress. If I can hammer out 35-45 pullups in an effort, doing the 21 for fran won't be intimidating at all. But if I constantly drop down to reduce my rest time it will take that much longer to progress to that many pullups.
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