[QUOTE=NO HYPE;72440923]
It appears as though the availability of intramuscular ribose is the limiting factor for the rate of resynthesis of ATP.....
[/quote]
this is of course a limiting factor, and oral ribose supplementation - even at high doses - can barely increase intramuscular ribose levels to a degree that would suffice to increase ATP synthesis at a rate that would translate into better performance.
[quote= NO HYPE][color=blue][B]The effects of four weeks of ribose supplementation on body composition and exercise performance in healthy, young, male recreational bodybuilders: a double-blind, placebo-controlled trial[/B][/color]
Accepted 22 May 2002. Available online 1 October 2002.
Background: Ribose is a pentose sugar that is present in ribonucleic acids, riboflavin, nucleotides, and adenosine triphosphate. Whether exogenous ribose administration affects skeletal muscle concentrations of total adenine nucleotides is unknown. Whether supplementation with ribose positively affects body composition or exercise performance in recreational bodybuilders also is unknown.
Objective: The purpose of this double-blind, placebo-controlled trial was to determine the effects of 4 weeks of ribose supplementation on body composition and exercise performance in healthy, young, male recreational bodybuilders.
Methods: [B]Healthy, male recreational bodybuilders aged 18 to 35 years were recruited and randomized to a ribose-supplemented group (10 g/d in powder formulation) or a placebo group (dextrose). Each subject participated in a heavy-resistance training program designed to increase skeletal muscle mass.[/B] Body composition (ie, body weight, body fat, lean body mass, fat mass, and bone mineral content) was assessed using dual-energy x-ray absorptiometry analysis. Muscular strength (as measured by a 1-repetition maximum-strength [1-RM] bench press) and total work performed (as measured by total repetitions for 10 sets of bench presses before muscular failure; 1-minute resting interval between sets) to muscular failure at a submaximal load (100% of pretest body weight) were ascertained. In addition, 24-hour dietary recalls were obtained before and after the study.
Results: Twenty men (mean age ? SE, 23.9 ? 1.4 years) were enrolled; 19 subjects completed 24-hour dietary recalls and exercise performance testing; 12 subjects completed the study (24-hour dietary recalls, exercise performance, and body composition). No baseline differences were found between the 2 groups for any of the measured parameters. [B]The ribose-supplemented group experienced a significant pretreatment-to-posttreatment increase in the total work performed, whereas the placebo group did not change significantly[/B] (24.5 ? 7.6 to 29.3 ? 7.5 repetitions; 19.6% ribose [P = 0.028] vs 34.1 ? 8.6 to 38.2 ? 8.0 repetitions, 12.0% placebo). [B]In addition, the ribose-supplemented group experienced a significant increase in 1-RM bench press strength, whereas the placebo group did not change significantly[/B] (114.1 ? 13.6 to 117.7 ? 14.0 kg, 3.2% ribose [P = 0.008] vs 129.6 ? 14.2 to 131.8 ? 14.5 kg, 1.7% placebo). No pretreatment-to-posttreatment within-group or between-group differences were found for any of the measures of body composition or the 24-hour dietary data.
[B]Conclusion: The results of this study indicate that supplementation with ribose 10 g/d for 4 weeks resulted in significant increases in muscular strength and total work performed in recreational bodybuilders in this study, although no significant changes in body composition or 24-hour dietary data were found.[/B] [url]http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VS8-46WMB3X-2&_user=10&_coverDate=08%2F31%2F2002&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=83e162e3cb6fd8eeb7744ad9d6aa94de[/url][/quote]
O.K., are you guys familiar with my main critique on many studies that investigate the effects of a supplement on performance?
what I have always criticised (e.g. in the Baylor studies done on arachidonic acid and on ecdysterone) is that the two gropus (treatment and placebo group) are apparently not appropriately matched!
please look at the numbers in this study now!
Number of repetitions in pretest:
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Ribose-Group: 24.5 +/- 7.6 repetitions
Placebo-Group: 34.1 +/- 8.6 repetitions
1-Rep-maximum (bench press) in pretest:
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Ribose-Group: 114.1 +/- 13.6 kg
PLacebo-Group:129.6 +/- 14.2 kg
Please note that the subjects in the placebo-group had on average an 39% higher rep number and 13.6% higher 1-rep maximum strength than the subjects in the ribose-group.
I can't help myself, but the baseline performance appear to not have been equal in the both groups.
So, there is no wonder that the noob-group (=the ribose gropup, with the low baseline performance) will benefit relatively more (percentage-wise) from a 4-week training than the more advanced group.
again, look at the numbers:
The noob-group (ribose-group) increased on average by 4.8 reps while the placebo group increased on average by 4.1 reps. so, both groups gained the same number of repetitions after a 4-week training.
similar thing with the 1-Rep bench-press: The ribose-people increased by 3.6 kg while the placbo-people increased by 2.2 kg. the ribose people gained relatively more, but don't forget that they started from a different baseline.
I wonder what kind of freaky statistics they did when they claim that at baseline (=pretest) the groups did not differ in any measured parameter.
Come on, 40% more reps in the placebo group at baseline and no difference? This sounds more than fishy to me.
You all know: never trust a statistics that wasn't tweaked by yourself.
let me illustrate this a little bit what apparently happened in this study:
let's say Jay Cutler takes Placebo and I take Ribose. We both do a 4-week strength training. after these 4 weeks, I have increased my reps and 1-rep max by 30% (10%) and Jay Cutler increased his reps and 1-rep maximum by only 3% (1%). YAY!!! ribose works!!!!! Ahhhmmm..., well...?
[quote=NO HYPE][color=blue][B]Ribose administration during exercise: Effects on substrates and products of energy metabolism in healthy subjects and a patient with myoadenylate deaminase deficiency[/B][/color]
Received: 27 June 1990 Revised: 26 October 1990 Accepted: 20 December 1990
Summary [B]Nine healthy men[/B] and a patient with myoadenylate deaminase deficiency were exercised on a bicycle ergometer (30 minutes, 125 Watts) with and without [B]oral ribose administration at a dose of 2 g every 5 minutes of exercise.[/B] Plasma or serum levels of glucose, free fatty acids, lactate, ammonia and hypoxanthine and the urinary hypoxanthine excretion were determined. [B]After 30 minutes of exercise without ribose intake the healthy subjects showed significant increases in plasma lactate (p<0.05), ammonia (p<0.01) and hypoxanthine (p<0.05) concentrations and a decrease in serum glucose concentration (p<0.05). When ribose was administered, the plasma lactate concentration increased significantly higher (p< 0.05) and the increase in plasma hypoxanthine concentration was no longer significant.[/B] The patient showed the same pattern of changes in serum or plasma concentrations with exercise with the exception of hypoxanthine in plasma which increased higher when ribose was administered. [url]http://www.springerlink.com/content/ul100240544177g2/[/url]
[color=blue][B]Effect of ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans[/B][/color]
Submitted 30 May 2003 ; accepted in final form 24 September 2003
[B]The effect of oral ribose supplementation on the resynthesis of adenine nucleotides and performance after 1 wk of intense intermittent exercise was examined. Eight subjects performed a random double-blind crossover design.[/B] The subjects performed cycle training consisting of 15 x 10 s of all-out sprinting twice per day for 7 days. After training the subjects received either ribose (200 mg/kg body wt; Rib) or placebo (Pla) three times per day for 3 days. An exercise test was performed at 72 h after the last training session. Immediately after the last training session, muscle ATP was lowered (P < 0.05) by 25 ? 2 and 22 ? 3% in Pla and Rib, respectively. In both Pla and Rib, muscle ATP levels at 5 and 24 h after the exercise were still lower (P < 0.05) than pretraining. [B]After 72 h, muscle ATP was similar (P > 0.05) to pretraining in Rib (24.6 ? 0.6 vs. 26.2 ? 0.2 mmol/kg dry wt) but still lower (P < 0.05) in Pla[/B] (21.1 ? 0.5 vs. 26.0 ? 0.2 mmol/kg dry wt) and higher (P < 0.05) in Rib than in Pla. [B]Plasma hypoxanthine levels after the test performed at 72 h were higher (P < 0.05) in Rib compared with Pla.[/B] Mean and peak power outputs during the test performed at 72 h were similar (P > 0.05) in Pla and Rib. [B]The results support the hypothesis that the availability of ribose in the muscle is a limiting factor for the rate of resynthesis of ATP.[/B] Furthermore, the reduction in muscle ATP observed after intense training does not appear to be limiting for high-intensity exercise performance. [url]http://ajpregu.physiology.org/cgi/content/abstract/286/1/R182[/url][/QUOTE]
so, again, no effects of ribose on performance!
and why is there an apparent contradiction between study 2 and 3 with regards to hypoxanthine levels? doesn't study 2 say that the after ribose hypoxanthine was lower than without ribose? and doesn't study three say that in the ribose group the hypoxanthine levels were higher?