Question about studies

Grassroots082

Grassroots082

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Every since I joined up AM, I have slowly been learning to use Pubmed. I saw Bobo's posts and even though its hard to understand everything (hard to understand 3/4 of it, need a ****ing webster's), it seems like alot of the studies that I have found contradict themselves.

For instance, today I was searching on pubmed (on my day off :think: ) about HMB supplementation in resistance training. I came upon a plethora of studies.

PRO HMB:

Effect of dietary supplements on lean mass and strength gains with resistance exercise: a meta-analysis.

Nissen SL, Sharp RL.

Department of Animal Science, Iowa State University, Ames 50011, USA. [email protected]

The purpose of this study was to quantify which dietary supplements augment lean mass and strength gains during resistance training. Peer-reviewed studies between the years 1967 and 2001 were included in the analysis if they met a predetermined set of experimental criteria, among which were at least 3-wk duration and resistance-training 2 or more times a week. Lean mass and strength were normalized for meta-analysis by conversion to percent change per week and by calculating the effect size for each variable. Of the 250 supplements examined, only 6 had more than 2 studies that met the criteria for inclusion in the meta-analysis. Creatine and beta-hydroxy-beta-methylbutyrate (HMB) were found to significantly increase net lean mass gains of 0.36 and 0.28%/wk and strength gains of 1.09 and 1.40%/wk (P < 0.05), respectively. Chromium, dehydroepiandrosterone, androstenedione, and protein did not significantly affect lean gain or strength. In conclusion, two supplements, creatine and HMB, have data supporting their use to augment lean mass and strength gains with resistance training.
[/QUOTE]

Creatine and beta-hydroxy-beta-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program.

Jowko E, Ostaszewski P, Jank M, Sacharuk J, Zieniewicz A, Wilczak J, Nissen S.

Institute of Sport and Physical Education, Biala Podlaska, Academy of Physical Education, Warsaw, Poland.

We investigated whether creatine (CR) and beta-hydroxy-beta-methylbutyrate (HMB) act by similar or different mechanisms to increase lean body mass (LBM) and strength in humans undergoing progressive resistance-exercise training. In this double-blind, 3-wk study, subjects (n = 40) were randomized to placebo (PL; n = 10), CR (20.0 g of CR/d for 7 d followed by 10.0 g of CR/d for 14 d; n = 11), HMB (3.0 g of HMB/d; n = 9), or CR-and-HMB (CR/HMB; n = 10) treatment groups. Over 3 wk, all subjects gained LBM, which was assessed by bioelectrical impedance analysis. The CR, HMB and CR/HMB groups gained 0.92, 0.39, and 1.54 kg of LBM, respectively, over the placebo group, with a significant effect with CR supplementation (main effect P = 0.05) and a trend with HMB supplementation (main effect P = 0.08). These effects were additive because there was no interaction between CR and HMB (CR x HMB main effect P = 0.73). Across all exercises, HMB, CR, and CR/HMB supplementation caused accumulative strength increases of 37.5, 39.1, and 51.9 kg, respectively, above the placebo group. The exercise-induced rise in serum creatine phosphokinase was markedly suppressed with HMB supplementation (main effect P = 0.01). However, CR supplementation antagonized the HMB effects on serum creatine phosphokinase (CR x HMB interactive effect P = 0.04). Urine urea nitrogen and plasma urea were not affected by CR supplementation, but both decreased with HMB supplementation (HMB effect P < 0.05), suggesting a nitrogen-sparing effect. In summary, CR and HMB can increase LBM and strength, and the effects are additive. Although not definitive, these results suggest that CR and HMB act by different mechanisms. -------Basically we have no ****ing idea and this study was useless as ****------------
Over-the-counter supplements and strength training.

Joyner MJ.

The group from the Exercise Science Department at Iowa State University and their colleagues in other departments at Iowa State have conducted two outstanding studies on human responses to resistance training. These have focused on the extent to which products that have been purported to enhance the responses to resistance training in humans (that are available over the counter to the public) actually work. One compound, androstenedione, seemed ineffective under the conditions studied; the other, HMB, seemed to enhance increases in lean body mass and strength in response to resistance training. These studies were well designed and well controlled and should serve as models for those interested in evaluating the impact of various interventions on body composition and strength in humans.
CON HMB:

Beta-hydroxy-beta-methylbutyrate (HMB) supplementation does not affect changes in strength or body composition during resistance training in trained men.

Slater G, Jenkins D, Logan P, Lee H, Vukovich M, Rathmacher JA, Hahn AG.

Sports Medicine Sports Science Division of the Singapore Sports Council, National Stadium, Singapore.

This investigation evaluated the effects of oral beta-hydroxy-beta-methylbutyrate (HMB) supplementation on training responses in resistance-trained male athletes who were randomly administered HMB in standard encapsulation (SH), HMB in time release capsule (TRH), or placebo (P) in a double-blind fashion. Subjects ingested 3 g x day(-1) of HMB or placebo for 6 weeks. Tests were conducted pre-supplementation and following 3 and 6 weeks of supplementation. The testing battery assessed body mass, body composition (using dual energy x-ray absorptiometry), and 3-repetition maximum isoinertial strength, plus biochemical parameters, including markers of muscle damage and muscle protein turnover. While the training and dietary intervention of the investigation resulted in significant strength gains (p < .001) and an increase in total lean mass (p = .01), HMB administration had no influence on these variables. Likewise, biochemical markers of muscle protein turnover and muscle damage were also unaffected by HMB supplementation. The data indicate that 6 weeks of HMB supplementation in either SH or TRH form does not influence changes in strength and body composition in response to resistance training in strength-trained athletes.
Effects of calcium beta-hydroxy-beta-methylbutyrate (HMB) supplementation during resistance-training on markers of catabolism, body composition and strength.

Kreider RB, Ferreira M, Wilson M, Almada AL.

Department of Human Movement Sciences & Education, The University of Memphis, TN 38152, USA. [email protected]

Calcium beta-hydroxy-beta-methylbutyrate (HMB) supplementation has been reported to reduce muscle catabolism and promote gains in fat-free mass and strength in subjects initiating training. However, whether HMB supplementation promotes these adaptations in trained athletes is less clear. This study examined the effects of HMB (as the calcium salt) supplementation during resistance training (6.9+/-0.7 hr x wk(-1)) on markers of catabolism, body composition and strength in experienced resistance-trained males. In a double-blind and randomized manner, 40 experienced resistance-trained athletes were matched and assigned to supplement their diet for 28 d with a fortified carbohydrate/protein powder containing either 0, 3 or 6 g x d(-1) of calcium HMB. Fasting venous blood and urine samples, dual energy X-ray absorptiometer-determined body composition, and isotonic bench press and leg press one repetition maximums (1 RM) were determined prior to and following 28 d of supplementation. HMB supplementation resulted in significant increases in serum and urinary HMB concentrations. However, no statistically significant differences were observed in general markers of whole body anabolic/catabolic status, muscle and liver enzyme efflux, fat/bone-free mass, fat mass, percent body fat, or 1 RM strength. Results indicate that 28 d of HMB supplementation (3 to 6 g x d(-1)) during resistance-training does not reduce catabolism or affect training-induced changes in body composition and strength in experienced resistance-trained males.
All the studies were performed w/in the past 5-6 years, nothing old. What gives?
 

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