Showing posts with label recovery drinks. Show all posts
Showing posts with label recovery drinks. Show all posts
Friday, August 20, 2010
Cocoa drink reduces DOMS. Really? Well, Maybe...
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What if cocoa in a drink of protein and carbs could mitigate DOMS - delayed onset muscle soreness? This is what researchers in a newly published Aug 2010 study have explored. And thank goodness, since most of us have struggled with DOMS at one time or another - new routine and next day or next few days our muscles pay for it. We walk like cowboys coming off a long jaunt in the saddle. Could Cocoa with your recovery beverage of choice be the winner? Let's remember, there are very few approaches that have been shown to help reduce the signs of DOMS - those are detailed in this 2parter here - and as Mike T Nelson comments how we measure DOMS is pretty important when making claims about what is actually reduced in the DOMS experience. Just to recap
Now in a way, there have been a couple kinda similar studies: one that looked at chocolate milk vs something like cytomax (all carbs) and something like endurox (4:1 carb to protein) for recovery, not DOMS. In that study chocolate milk was shown to be as good as a carb beverage and better in a *certain test condition* than protein + carbs well all of us cheer that low-fat chocolate milk option. Except for the tons of folks for whom milk is not a happy thing, from lactose intolerance to immune responses with dairy. Intriguingly various dairy interests supported the research.
Just The Cocoa Facts, Sir. The question has been bound to come up well, what if we ditch the dairy and just look at the chocolate bit, or in this case, the cocoa bit? Especially if this time the research is supported not by a dairy but a chocolate company. Hershies in this case. The researchers who did the reesarch also decided not to look at the big picture of recovery but to focus on DOMS reduction. Why? Because, they argue, we seem to see free-radical release go up conincident with the muscle damage of exercise, so perhaps, putting an anti-oxidant like cocoa into the system may help mitigate those effects and possibly reduce the DOMS experience. Interesting. And there's no small challenge they say in trying to measure anti-oxidant effect:
Starting from Scratch. So thar ya go: the researchers will put together their own drink and compare it with water for effect on DOMS. They are going to use TWO of the four markers for DOMS described above: the biomarkers like CK and LEFS - Lower Extremity Functional Sacle. In LEFS, participants report on a scale of 0-4 the perceived difficulty of carrying out a physical task (actual survey here, pdf). So one biological test and one subjective scoring test. It is SUCH a drag that DOMS tests are not standardized! And asking someone to reflect *about* how they'd find getting out of a car if they haven't gotten out of a car, for instance, is yup pretty durn subjective. Interesting, but subjective when there are measures like ROM and force production also available, and even perceived soreness from pressure.
Findings about Cocoa in Particular? That aside, what did the authors find? Not too much. The drink had no effect on the biomarkers of damage. So they didn't mitigate its biological effects. The authors think however that their use of LEFS rather than the usual in DOMS studies VAS is a step up because LEFS asks about daily activities rather than just how a poke feels. And as to their results with LEFS checked at 24 and 48 hour intervals?
Here's personally where i'd actually like to see the raw data just to confirm that the direction of change for the non-drink group WAS that their scores went down (got worse) rather than up. We have to trust the authors' reporting. And i hate that.
The authors also spend considerable time speculating over why their form of cocoa rather than dutched may be a better use of cocoa to what's in chocolate milk
Concludium
This is why science is so cool: after an entire paper of data, experimental set up, discussion, yada yada yada, this is what we get
Related Work. Interestingly, a previous study by Green and company that states rather categorically in its title that Carb or Carb/Pro drinks have no effect on DOMS is set aside by the present researchers. They suggest that really, Green's study didn't actually elicit anything with which to have a response to mitigate:
So all the more reason for the the authors to have studied a similar drink without the cocoa, rather than water, or along with water, they would have a stronger basis to assert that it's their anti-oxidant/flavonoid cocoa that's the Special Sauce for toning down DOMS. So why mightn't the authors have done something so obvious? I'd speculate something like the following.
The Gritty Realities of Reseasrch on a Shoe string - or Little Hershies Kiss
When one is designing a study, Saul Greenberg once suggested an heuristic to me about research i live by: think about the optimal outcomes of the study proposed. What will the best results be? Is that optimal outcome significant? If the authors of this paper had run that exercise what would they have said: the BEST we will be able to say if our results have an effect is that we will (a) see a difference in biomarkers and (b) see a difference in perceived soreness. And givent that, what will be be able to say about cocoa? Nothing. The best we will be able to say is that cocoa was in the mix and maybe it contributed to decreased DOMS, so best case: it's worth doing the next study to isolate this out.
Why not do the full study the first time? It would take either longer or would take more participants. There are costs to that. So, given that the authors didn't see any A but they did get some B which is sufficient to say "maybe" cocoa plays a role, i hope Hershies is sufficiently keyed up by this "maybe" to fund the next study that would compare the two formulations. Which will be the longer or bigger trial anyway. That could have been done from the start. But maybe Hershies said "what can you do with X dollars? if we like what you do maybe we'll give you X*y" - and so there we are. Maybe. I speculate wildly.
Well what can i tell ya? What can i possibly say?
All we do know from the data is that taking the drink before exercise rather than after exercise had no real effect on DOMS; taking the drink afterwards, the authors suggest based on their 24-48 hours DOMS increasing, shows it does.
So maybe maybe something in the composition and timing of the beverage that helped. What bit is a rather open question. One might say ah yes but there are other studies comparing say c.milk with carb/protein and the c.milk did better so it must be the C for Chocolate? Maybe. Maybe maybe and more maybe.
Might be a fun personal experiment: next time a new routine is in the offing, blend in those whole cacao beens and go nuts! you may even feel better for the next 24-48 hours. It's chocolate! how could it hurt?
Citations
Related
What if cocoa in a drink of protein and carbs could mitigate DOMS - delayed onset muscle soreness? This is what researchers in a newly published Aug 2010 study have explored. And thank goodness, since most of us have struggled with DOMS at one time or another - new routine and next day or next few days our muscles pay for it. We walk like cowboys coming off a long jaunt in the saddle. Could Cocoa with your recovery beverage of choice be the winner? Let's remember, there are very few approaches that have been shown to help reduce the signs of DOMS - those are detailed in this 2parter here - and as Mike T Nelson comments how we measure DOMS is pretty important when making claims about what is actually reduced in the DOMS experience. Just to recapLet's review what's measured in assessing DOMS in the literature.
Study Designing: So if one were to see if cocoa were effective how would we do it? Normally in an experimental condition, there's the thing being tested - in this case cocoa - and then there's a control - like water to see what happens without any intervention - and sometimes - in fact often - there's an alternative protocol, so you can see not just if the thing you're interested in has an effect but if it's the same or better than some usual standard - like a carb or protein+carb drink.Caveat Emptor
- what's in the blood: usually there are markers in the blood like creatine kinase and LDH - these are markers of muscle damage - we may have the same CK levels and have very different responses to soreness
- then there's the subjective measures of soreness themselves using rating scales.
- then there's the more objective bits: Range of motion and force production.
B2D buddie Mike T. Nelson of extremehumanperformance.com asks the question: is the experience of soreness directly correlated to a drop in performance? Mike in conversation makes the point that pain perception being a brain thing is going to be pretty individual. So how DOMS success is measured is something to bare in mind when looking at the studies following that claim to be effective against DOMS - are we talking DOMS pain reduction (always nice) or performance in a DOMS state?
Now in a way, there have been a couple kinda similar studies: one that looked at chocolate milk vs something like cytomax (all carbs) and something like endurox (4:1 carb to protein) for recovery, not DOMS. In that study chocolate milk was shown to be as good as a carb beverage and better in a *certain test condition* than protein + carbs well all of us cheer that low-fat chocolate milk option. Except for the tons of folks for whom milk is not a happy thing, from lactose intolerance to immune responses with dairy. Intriguingly various dairy interests supported the research. Just The Cocoa Facts, Sir. The question has been bound to come up well, what if we ditch the dairy and just look at the chocolate bit, or in this case, the cocoa bit? Especially if this time the research is supported not by a dairy but a chocolate company. Hershies in this case. The researchers who did the reesarch also decided not to look at the big picture of recovery but to focus on DOMS reduction. Why? Because, they argue, we seem to see free-radical release go up conincident with the muscle damage of exercise, so perhaps, putting an anti-oxidant like cocoa into the system may help mitigate those effects and possibly reduce the DOMS experience. Interesting. And there's no small challenge they say in trying to measure anti-oxidant effect:
Although various experiments have been conducted to investigate the effect of antioxidant dietary supplementation on biomarkers of skeletal muscle damage and oxidative stress, the results are often equivocal and difficult to compare because of considerable variations in sampled populations and exercise protocols (18). Moreover, the practical application of antioxidant supplementation research studies has been considerably limited because of an overwhelming failure for measuring and reporting functional indices of exercise-induced muscle damage such as soreness (18). Therefore, the purpose of this pragmatic experiment was twofold: first to investigate the overall effectiveness of a welldefined custom manufactured cocoa-based protein and carbohydrate prototype drink on skeletal muscle cell damage and inflammatory biomarkers and perceived soreness associated with exhaustive exercise and secondly to assess if drink consumption before exercise offered additive effects. We hypothesized that the cocoa-based protein and carbohydrate prototype drink would decrease skeletal muscle cell and inflammatory biomarkers and perceived soreness compared to water, a standard fluid often consumed during exercise bouts.We also hypothesized that consuming the test drink before exercise would elicit further reductions in oxidative stress markers and perceived soreness.
Starting from Scratch. So thar ya go: the researchers will put together their own drink and compare it with water for effect on DOMS. They are going to use TWO of the four markers for DOMS described above: the biomarkers like CK and LEFS - Lower Extremity Functional Sacle. In LEFS, participants report on a scale of 0-4 the perceived difficulty of carrying out a physical task (actual survey here, pdf). So one biological test and one subjective scoring test. It is SUCH a drag that DOMS tests are not standardized! And asking someone to reflect *about* how they'd find getting out of a car if they haven't gotten out of a car, for instance, is yup pretty durn subjective. Interesting, but subjective when there are measures like ROM and force production also available, and even perceived soreness from pressure.
Findings about Cocoa in Particular? That aside, what did the authors find? Not too much. The drink had no effect on the biomarkers of damage. So they didn't mitigate its biological effects. The authors think however that their use of LEFS rather than the usual in DOMS studies VAS is a step up because LEFS asks about daily activities rather than just how a poke feels. And as to their results with LEFS checked at 24 and 48 hour intervals?
For those trials where the test drink was ingested after exercise we noted significantly less of a reported change from 24 to 48 hours by the participants. This indicated a decrease in perceived DOMS and therefore less difficulty in performing various physical tasks 48 hours postexercise.Why does less change between 24-48 hours mean decreased DOMS?
DOMS gradually increases 24 hours postexercise and typically peaks 48 hours postexercise before beginning to decline (16).Now i'm a bit annoyed that for this to be the BIG RESULT, we only get a couple summative values for the questionnaire rather than the raw data for lets face it, only 13 participants. Here it is
Consuming the test drink after exercise resulted in a mean change of 2.6 plus or minus 6 compared to 13.7 plus or minus 10 for the control.In LEFS, the total score is out of 100, with a 90% confidence interval. What this suggests is that the scores changed by about 6 times as much in the non-drink case, which the authors suggest means that DOMS didn't get much worse in the drink case.
Here's personally where i'd actually like to see the raw data just to confirm that the direction of change for the non-drink group WAS that their scores went down (got worse) rather than up. We have to trust the authors' reporting. And i hate that.
The authors also spend considerable time speculating over why their form of cocoa rather than dutched may be a better use of cocoa to what's in chocolate milk
Concludium
This is why science is so cool: after an entire paper of data, experimental set up, discussion, yada yada yada, this is what we get
Based on the findings of our experiment we conclude that a recovery drink composed of a carbohydrate-to-protein ratio of 3.5:1 with the addition of flavonol-rich cocoa may (emaphasis mine -mc) decrease perceived muscle soreness after exercise.There is nothing in the results to show that any one of the elements in this drink - the protein, the carbs or the chocolate - has any particular effect on mitigating DOMS. Indeed, one previous study that said cocoa is fine for ldl, but not for reducing inflamation, which would kinda suggest that cocoa mayn't help with DOMS. The authors say that while there results show a similar lack of change in biomarkers, maybe it's the combination of protein/carb/cocoa that's having the effect. That is the subjective response.
Related Work. Interestingly, a previous study by Green and company that states rather categorically in its title that Carb or Carb/Pro drinks have no effect on DOMS is set aside by the present researchers. They suggest that really, Green's study didn't actually elicit anything with which to have a response to mitigate:
Therefore, it may be possible that the protocol of Green et al. did not impose adequate skeletal muscle cell damage to induce substantial perceived postexercise muscle soreness in participants.This helps the authors to say it's not cocoa alone; not clear that it's really not protein/carbs alone.
So all the more reason for the the authors to have studied a similar drink without the cocoa, rather than water, or along with water, they would have a stronger basis to assert that it's their anti-oxidant/flavonoid cocoa that's the Special Sauce for toning down DOMS. So why mightn't the authors have done something so obvious? I'd speculate something like the following.
The Gritty Realities of Reseasrch on a Shoe string - or Little Hershies Kiss
When one is designing a study, Saul Greenberg once suggested an heuristic to me about research i live by: think about the optimal outcomes of the study proposed. What will the best results be? Is that optimal outcome significant? If the authors of this paper had run that exercise what would they have said: the BEST we will be able to say if our results have an effect is that we will (a) see a difference in biomarkers and (b) see a difference in perceived soreness. And givent that, what will be be able to say about cocoa? Nothing. The best we will be able to say is that cocoa was in the mix and maybe it contributed to decreased DOMS, so best case: it's worth doing the next study to isolate this out.
Why not do the full study the first time? It would take either longer or would take more participants. There are costs to that. So, given that the authors didn't see any A but they did get some B which is sufficient to say "maybe" cocoa plays a role, i hope Hershies is sufficiently keyed up by this "maybe" to fund the next study that would compare the two formulations. Which will be the longer or bigger trial anyway. That could have been done from the start. But maybe Hershies said "what can you do with X dollars? if we like what you do maybe we'll give you X*y" - and so there we are. Maybe. I speculate wildly.
Well what can i tell ya? What can i possibly say?
All we do know from the data is that taking the drink before exercise rather than after exercise had no real effect on DOMS; taking the drink afterwards, the authors suggest based on their 24-48 hours DOMS increasing, shows it does.
So maybe maybe something in the composition and timing of the beverage that helped. What bit is a rather open question. One might say ah yes but there are other studies comparing say c.milk with carb/protein and the c.milk did better so it must be the C for Chocolate? Maybe. Maybe maybe and more maybe.
Might be a fun personal experiment: next time a new routine is in the offing, blend in those whole cacao beens and go nuts! you may even feel better for the next 24-48 hours. It's chocolate! how could it hurt?
Citations
McBrier NM, Vairo GL, Bagshaw D, Lekan JM, Bordi PL, and Kris-Etherton PM (2010). Cocoa-based protein and carbohydrate drink decreases perceived soreness after exhaustive aerobic exercise: a pragmatic preliminary analysis. Journal of strength and conditioning research / National Strength & Conditioning Association, 24 (8), 2203-10 PMID: 20634742
Karp JR, Johnston JD, Tecklenburg S, Mickleborough TD, Fly AD, & Stager JM (2006). Chocolate milk as a post-exercise recovery aid. International journal of sport nutrition and exercise metabolism, 16 (1), 78-91 PMID: 16676705
Mathur S, Devaraj S, Grundy SM, & Jialal I (2002). Cocoa products decrease low density lipoprotein oxidative susceptibility but do not affect biomarkers of inflammation in humans. The Journal of nutrition, 132 (12), 3663-7 PMID: 12468604
Wiswedel, I., Hirsch, D., Kropf, S., Gruening, M., Pfister, E., Schewe, T., & Sies, H. (2004). Flavanol-rich cocoa drink lowers plasma F2-isoprostane concentrations in humans Free Radical Biology and Medicine, 37 (3), 411-421 DOI: 10.1016/j.freeradbiomed.2004.05.013
Green MS, Corona BT, Doyle JA, & Ingalls CP (2008). Carbohydrate-protein drinks do not enhance recovery from exercise-induced muscle injury. International journal of sport nutrition and exercise metabolism, 18 (1), 1-18 PMID: 18272930
Related
- Nutrient timing May make a difference for recovery
- Carbs or Protein before bed?
- Kinds of protein for that recovery window?
- Supplement Curmudgeon - does that stuff do anything for you?
- Creatine and Beta Alanine for Aerobic Endurance?
- How about CoQ10 for endurance?
- would you like a heart rate monitor with that?
PDF
Saturday, October 3, 2009
Nutrient timing *may* make difference - for strength, body comp, muscle fiber...
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Could changing when you have a recovery drink have a significant effect on strength, body comp and other performance factors? It may be that simple. If you like your workout routine, but want it to produce better results, you may find that changing one thing has a not insignificant effect. There seems to be significant benefit to strength, muscle fiber, body composition and muscle glycogen uptake based simply on when nutrients are taken around a workout. Likewise this nutrient timing requires no other change to one's diet to have this effect.
A cool thing about this study is that participants were used to doing resistance work; they aren't newbies (as many studies use).
Here's what they had in their drinks:
Strength & Muscle gains What the above breaks down to show is that there was a statistically significant difference (only 5% likelihood that the finding is based on chance) in STRENGTH performance improvements with the group in things like the 1RM. Intriguingly, the cross sectional area of muscle went up (hypertrophy) more than the other group of the fast twitch fibers in particular - the ones uses especially in power/strength work.
Creatine and Hypertrophy. So, nothing too surprising in what the good stuff in the drinks is. If i could redo this study, i'd take out the creatine to study separately, as the consensus there has seemed to be that one can take it anytime to be valuable. That said, the authors here in the discussion suggest that there may be particular benefit to taking creatine around time of exercise.
Body Comp - another interesting finding is that the effect of timing on body comp (bf%, lean mass) was also significant.
Citation:
CRIBB, P., & HAYES, A. (2006). Effects of Supplement Timing and Resistance Exercise on Skeletal Muscle Hypertrophy Medicine & Science in Sports & Exercise, 38 (11), 1918-1925 DOI: 10.1249/01.mss.0000233790.08788.3e Tweet Follow @begin2dig
Could changing when you have a recovery drink have a significant effect on strength, body comp and other performance factors? It may be that simple. If you like your workout routine, but want it to produce better results, you may find that changing one thing has a not insignificant effect. There seems to be significant benefit to strength, muscle fiber, body composition and muscle glycogen uptake based simply on when nutrients are taken around a workout. Likewise this nutrient timing requires no other change to one's diet to have this effect.Bottom line: taking Creatine Monohydrate, Protein and Carbs "just before" & "right after" workout is a really cheap win to improving strength, body comp and muscle type improvements. The other group had taken the same fuel in the AM before any other food and late in the PM after anything else so fuel ups were at least 5 hours on either side of a workout.
Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy.
Exercise Metabolism Unit, Center for Ageing, Rehabilitation, Exercise and Sport; and the School of Biomedical Sciences, Victoria University, Melbourne, Victoria, Australia.
PURPOSE: Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program. METHODS: In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content. RRESULTS: PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content.
CONCLUSION: Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.
A cool thing about this study is that participants were used to doing resistance work; they aren't newbies (as many studies use).
Here's what they had in their drinks:
All participants were prescribed 1 g of the supplement per kilogram of body weight (1 g-1·kg-1 bw), to be consumed twice on training days only. The supplement contained (per 100 g), 40 g of protein (from whey isolate), 43 g of carbohydrate (glucose), < 0.5 g of fat, and 7 g of CrM and was provided by AST Sport Science (Golden, CO). This dose provided an 80-kg participant with 32 g of protein, 34.4 g of carbohydrate, < 0.4 g of fat, and a 5.6 g of CrM in each serving (a total of 1124 kJ). The chosen supplement dose was based on previously reported intakes of this population (18) and was similar to previous studies that had involved protein (1) or CrM (8) supplementation close to RE. The participants were instructed to maintain their habitual daily diet during the trial.
Strength & Muscle gains What the above breaks down to show is that there was a statistically significant difference (only 5% likelihood that the finding is based on chance) in STRENGTH performance improvements with the group in things like the 1RM. Intriguingly, the cross sectional area of muscle went up (hypertrophy) more than the other group of the fast twitch fibers in particular - the ones uses especially in power/strength work.
Creatine and Hypertrophy. So, nothing too surprising in what the good stuff in the drinks is. If i could redo this study, i'd take out the creatine to study separately, as the consensus there has seemed to be that one can take it anytime to be valuable. That said, the authors here in the discussion suggest that there may be particular benefit to taking creatine around time of exercise.
it could be suggested that supplement timing promotes more efficient Cr accumulation within muscle and, therefore, greater strength gains and muscle hypertrophy during RE training. However, this aspect was not examined directly. Based on the results obtained, further investigations are warranted to examine dose responses and the extent of Cr accumulation during RE, and to fully elucidate the contributions of both CrM and whey protein to chronic adaptations during training.
Body Comp - another interesting finding is that the effect of timing on body comp (bf%, lean mass) was also significant.
A group×time interaction (P <>
Muscle Glycogen. Higher in the Pre/Post group too - and at that 10 weeks after the trial finished. The authors propose an argument for this finding.
Therefore, it could be suggested that PRE-POST supplement timing not only promoted more efficient CrM accumulation within muscle, but that this strategy may have also promoted more efficient muscle glycogen restoration during the RE program. In turn, these benefits may have enabled greater work capacity during subsequent workouts, thus helping to promote greater strength improvements and muscle hypertrophy. Although work capacity was not assessed, the significantly greater hypertrophy responses (in three of three assessments) and 1RM strength improvements (two of three assessments) demonstrated by the PRE-POST group after the program support this theory.Other studies have looked at taking on board fuel close to RE, but the authors of this study claim that the unique thing here is that no one changed their diet: they just added the supplement drink. The authors write:
In conclusion, although there has been a sound theoretical basis for expecting a beneficial effect from supplement timing, this is the first study to clearly demonstrate that this strategy results in greater strength and body composition improvements (i.e., a gain in lean mass and a decrease in body fat percentage) as well as muscle hypertrophy, compared with supplementation at times outside of the workout period. Unlike previous work that has examined chronic adaptations from nutrient consumption close to RE, a significantly greater muscle hypertrophy response from supplement timing was evident at three different levels (i.e., a greater increase in LBM, hypertrophy of the type IIa and IIx fibers, and contractile protein accrual). Additionally, these results were obtained with participants maintaining their normal eating patterns throughout the program. Therefore, we conclude that supplement timing represents a simple but effective strategy to enhance the adaptations that are desired from RE training.This study is from 2006. It may be that other studies since then that i've yet to find qualify these results differently. Likewise, the authors didn't use a total control group - a group that did no extra supplementation at all - it would be interesting to see if that outside RE time supplementation had ANY benefit at all.
That said, it does seem pretty compellingly simple, as the authors suggest, that just by putting pre/post protein/cho/CrM drinks around RE workouts is an Easy Win for supporting strength.
Related Posts
- A minute with mike 1: bcaa, leucine, whey: which when and why?
- A minute with mike 2: post workout recovery window
- nutrition in general: eating is a habit, and change is pain. here's help (inside p90x article)
- free 40+ page overview of approach that uses this nutrient timing stuff (precision nutrition)
Citation:
CRIBB, P., & HAYES, A. (2006). Effects of Supplement Timing and Resistance Exercise on Skeletal Muscle Hypertrophy Medicine & Science in Sports & Exercise, 38 (11), 1918-1925 DOI: 10.1249/01.mss.0000233790.08788.3e Tweet Follow @begin2dig
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