October 12, 2012
Effects of Dehydration during Cycling on Skeletal Muscle Metabolism in Females

Exercising in a dehydrated state can hurt performance.  That really is nothing new.  However, what is not known is how dehydration can effect substrates being used by the  muscle during exercise, particularly in women.  So, this one is for you ladies.

Introduction:  Did you know that a 2% loss in body mass because of dehydration can elevate HR, core temperature, and the osmolarity of blood plasma?  Did you also know that it is said that women thermoregulate less effectively because of a higher core temperature during the same exercise load as men?  In fact, females usually experience a quicker rise in core temperature during exercise.  Depending on core temperature during exercise, the body can switch between using muscle glycogen or fat.  Therefore, you could say that depending on hydration status (which effects core temperature) the body will switch between these two fuel sources as well.  But which one?  The hypothesis in this study states that women will rely more heavily on whole body carbohydrate oxidation as well as the breakdown of glycogen from muscle during dehydrated exercise.

Methods:  Nine women underwent cycling at 65% VO2peak for 120 min.  Some received fluids during the exercise and the others did not.  It is important to note that before the exercise trial, both groups were properly hydrated.  Thus, this study is just examining the consequences of not drinking water during prolonged endurance exercise.

Results: One way to measure whether or not you are using carbohydrates or fat during exercise is by a method called indirect calorimetry, which can provide you with a RER.  RER, as I’ve described before, is the respiratory exchange ratio.  A RER of 1 means you are using primarily carbohydrates and a RER closer to 0.75 means you are using primarily fat.  With that said, the RER of the dehydrated group was significantly higher than the hydrated group, meaning that they were using more carbohydrates during exercise.  Likewise, carbohydrate oxidation and total body carbohydrate oxidation was higher in the dehydrated group whereas fat oxidation was lower.  The dehydrated group had a significantly higher core temperature and heart rate as well.

Discussion:  At this point you would probably like to know why being dehydrated makes the body rely more on carbohydrates rather than fat.  There currently is no answer to that; however, the authors suggest three theories behind it.

  1. An augmented nervous system response from the adrenal glands leading to activation of an enzyme that uses glycogen.
  2. Low energy levels that are sensed in cells
  3. Higher intramuscular temperature (which appears to be the primary mechanism)

My input:  It is now being understood a little more why dehydration causes performance deficits.  Clearly, if you are going to tap into your muscle glycogen faster, you will not be able to perform as long as if you were using primarily fat, which is very energy rich.  Still, more needs to be done to understand the exact mechanism for the switch.

Logan-Sprenger et al Med Sci Sports Exerc. 2012 Oct;44(10):1949-57.

September 17, 2012
Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism.

Maximize your muscle protein synthesis after weight training, bros.  I’ll highlight for you a recent review, which the scientist nerds can read entirely for free here, from Dr. Stuart M. Phillips.  I encourage you to take the time to read this one.

Introuction:  When scientists talk about muscle protein synthesis they are referring to accruing muscle proteins in an overall net positive balance.  That is to say, taking the most basic form of proteins, amino acids, and eventually creating structural muscle (aka hypertrophy).  Normally, this is done by adding to already existing contractile machinery of the muscle cells.  Researchers suggest that muscle protein synthesis (MPS for now on) is controlled by certain factors including dose, food source, and timing.  Let’s see what Dr. Phillips has to say about each of these areas.

"The anabolic window" -Timing

It’s like the holy grail of muscle growth for bros.  ”You can’t miss the window or you ruined the entire workout.”  Well, that’s a bit exaggerated.  Phillips states that, "It is now unequivocal that immediate post-exercise amino acid provision is an effective nutrition based strategy to enhance MPS above rates observed with exercise alone.”  Early post-exercise ingestion of amino acids or protein comes from studies that showed that exercise induced increases in rates of MPS are greatest right after exercise; approximately 100-150% above basal rates.  However, it may not be that big of a deal if you miss this window.  If you look at the figure below, the increase in MPS is in fact greater after exercise but can remain elevated for up to 48 hours.  Phillips suggests that consuming protein during these later times as well can be just as beneficial as ingesting protein directly after exercise.


MPS after resistance exercise

More importantly, Philips discusses the importance of actual exercise intensity and how it relates to muscle failure.  This is in lines with a study I touched upon in the past.  Looking at yet again another figure below, you can see that groups that take resistance exercise to failure, regardless if they’re using heavy load and low volume, or a light load and high volume had an enhanced amino acid sensitivity to muscle protein synthesis.  Let me say that again, IRREGARDLESS OF HOW MUCH WEIGHT YOU USE, as long as you are taking the muscle to failure, you will increase your rates of muscle protein synthesis more than loads not till failure. 

High vs low load

Protein source


Let it be noted that whey, egg albumin, soy, casein, and beef have all been shown scientifically to be able to stimulate MPS.  However, the Philips group has shown in the past that whey and milk can increase MPS greater than soy products following resistance exercise (this could be due to differences in amino acid profiles and/or digestion kinetics).  Why is whey fast-digesting and casein slow-digesting?  Every one knows that or will tell you that but do they even have an explanation why?  Phillips drops a knowledge bomb with one sentence, Whey protein is acid soluble and is associated with a very rapid, large, but transient increase in postprandial amino acid availability,  while casein coagulates and precipitates when exposed to stomach acid and the resultant dairy curd is slowly released from the stomach resulting in a much more moderate but sustained rise in plasma amino acids.”  I love knowledge bombs.

Dose

It is still accepted that in young healthy individuals, approximately 20-25g (which corresponds to approximately 8-10g of essential amino acids) of a rapid digesting protein source (whey or milk) can help maximize stimulation of MPS after resistance exercise. 


There you have it.  Now, I’m off to eat some beef.

September 12, 2012
Aerobic Exercise Alters Skeletal Muscle Molecular Responses to Resistance Exercise

Weight training and some form of aerobic in the same session.  Does it hurt or help?

Introduction:  Exercise scientists use the term concurrent exercise when referring to resistance training and aerobic exercise being performed in the same session.  These two modes of exercise are different in regards to skeletal muscle profiles and therefore may not be compatible with one another on the cellular level.  This is noted as an “interference effect” between the different signals occurring in the muscle.  The purpose of this study was to see the effects of a short bout of aerobic exercise on the molecular responses that are supposed to control exercise-specific muscle adaptations to resistance exercise.

Methods:  The subjects (9 men) underwent one-legged aerobic exercise in the morning followed by four sets of resistance exercise six hours later.  One leg received both aerobic and resistance exercise while the other volunteer’s leg served as a control and only received resistance exercise.  Standardized meals were given the day before and the day of to each person and muscle biopsies were taken.

Results:  The leg that underwent both aerobic and resistance exercise decreased in muscle glycogen more than the leg that just did resistance (makes sense).  A well-known marker of mitochondrial biogenesis was higher in the leg that underwent both training modes.  Another marker or muscle size regulation (myostatin) was significantly lower in both the resistance trained leg and in the leg that underwent both modes.  Finally, a marker of protein synthesis was higher in the leg that underwent aerobic plus resistance training than the other leg.

Discussion/conclusion:  From this study, the authors conclude that concurrent exercise may in fact enhance the skeletal muscle anabolic environment although it is important to note that these differences between legs were modest.  An interesting finding is that the well-known marker of mitochondrial biogenesis which is usually increased from endurance training also increased from the resistance trained leg as well.  Myostatin inhibits muscle hypertrophy and the finding that both legs decreased myostatin levels shows that both training modes could be effective at increasing muscle mass (although both legs did resistance and this very well may be the main reason for that).  In conclusion, the authors state that both exercise types can be scheduled on the same day without compromising important molecular signals in the muscle.  

My input: I’ve written about this previously on my blog.  This study has similar results to the other in that they conclude resistance training after aerobic training may in fact enhance muscle machinery and subsequently help with performance.  Although, the two studies are truly hard to compare due to the fact that this current one waited 7 hours later to do the resistance training, while the previous one I wrote about hit the weights immediately after.  A great strength of this study was using one leg for aerobic and resistance exercise and using the person’s other leg as the control that just received resistance exercise.  As far as a doing weights after cardio on the same day in the gym, there seems to be no immediate inference effect but this can not yet be extrapolated to more long-term sessions.

Lundberg et al Med Sci Sports Exerc. 2012 Sep;44(9):1680-8.

August 10, 2012
Protein Ingestion before Sleep Improves Postexercise Overnight Recovery

"Yo, you gotta take your casein before bed so you stay anabolic.  Steady flow of amino acids while I sleep." How many times have you heard that?  How many people have showed you a study validating it?  Finally, one exists.

Introduction:  It is hypothesized that ingesting protein before sleep could be beneficial to increase plasma amino acid availability, stimulate skeletal muscle protein synthesis and increase whole-body protein balance during sleep.  Thus, this group took 16 recreationally active young men and after a single bout of resistance training gave them either casein protein or a placebo before bed.  This is the first study to look at the effect of ingesting casein protein immediately before sleep and subsequently seeing how it effects protein synthesis and protein balance overnight.

Methods:  All subjects received a standard meal the evening before the test and a standardized diet throughout the experimental day.  Tracers were implemented in this study which allows for measurements of certain molecule in the blood.  A tracer is a molecular that contains radioactive isotopes that can be measured by machines to see the overall flux of the molecule throughout the body.  In this study, the researchers traced radioactive amino acids (it’s safe because they are stable isotopes, trust me)throughout the night following the exercise protocol.  The protocol consisted of leg extensions and leg press and was performed three hours before bed.

Results:  After ingestion of protein before sleep, the total essential amino acid concentrations in the plasma increased rapidly and stayed higher throughout the night as compared to the placebo group.  For the tracer, the amount of protein available from the plasma-derived amino acids was 50% higher in the protein ingestion group at time 7.5hrs after sleep compared to the placebo.  Finally, whole-body protein synthesis rates were higher in the protein group versus the placebo group.

Discussion:  It is evident that the casein protein was in fact digested and absorbed normally throughout the night because the tracer used in this case came directly from the casein protein shake.   Not only did they observe and increase in whole-body protein synthesis with the blood plasma samples, but the group also showed an increase in synthetic rate by taking muscle biopsies as well.  Of course this could not be confirmed throughout the night but only before bed otherwise the person would not be able to sleep when the biopsy was being performed.  Also, it is important to keep in mind that this is an acute (one-time) bout of resistance training and not chronic (long-term).

Conclusion:

  1. Casein protein at bedtime is effectively digested and absorbed which would lead to an increase in available amino acids from blood plasma overnight
  2. Casein protein at bedtime stimulates muscle protein synthesis rates which would increase overnight protein balance.
My input: This study highlights the practicality and necessity of using tracers.  Without labeling the amino acid in the casein drink, it would be difficult to tell whether or not the amino acids in the plasma are coming from inside the body (endogenous) or what was ingested (exogenous).  The authors clearly show in the figures that the rise in the amino acids come from the isotope labelled casein source that they provided.  Now for the first time, you can all finally tell your friends it is a good idea to supplement with casein before bed because science suggested it.


Res et al Med Sci Sports Exerc. 2012 Aug;44(8):1560-9.

August 8, 2012
Simple but powerful thought of the week.

1kg (2.2lbs) of skeletal muscle contains approximately 650g of intracellular water.  Representing normally around 40% of body weight, skeletal muscle in the whole body contains 80 grams of amino acids in the intracellular pool.  The amino acids glutamine, glutamic acid, and alanine contribute approximately 80% to this pool.  

Bergström et al 1974

June 20, 2012
Sex-based comparison of protein synthesis following resistance exercise.

The title says it all.  Who is better able to recover following resistance training?  The results may surprise you (or even motivate you).

Introduction:  Researchers sought out to see whether men or women have higher rates of protein synthesis during the early (1-5) and late (24-48) hour recovery periods.  In addition to the resistance training, they also gave a dose of whey protein (25g) that is expected to induce maximal muscle protein synthesis.  A secondary aim of this study was to see if the large amount of testosterone released by men post-exercise (10 to 15 times higher in men than women) would have an additive effect on muscle protein synthesis that women would not be able to obtain.

Methods:  Eight men and eight women who were participating in regular physical activity took part in this study.  The bout of exercise was an intense bout with 5 sets of 10 reps at 90% of a persons 10 rep maximum on the leg press as well as 3 sets of 12 reps of leg extensions/leg curls supersets.  Upon finishing this workout, subjects were given 25g of whey protein.

Results:  Starting rates of protein synthesis were similar between men and women.  After exercise, protein synthesis increased in men and women at 1-3 hours and remained elevated at 26-28 hours after with no difference between the sexes.Testosterone was approximately 45 times greater in men than women fifteen minutes after exercise but did not have an effect on muscle protein synthesis more than that of women.

Discussion/Conclusion:  This study shows that there are similar rates of muscle protein synthesis as well as anabolic cellular signaling events between men and women following resistance training plus a 25g dose of whey protein in the earl and late phases of post-exercise recovery.  Even though men had a far greater increase in testosterone than women post-exercise, it was not enough to increase protein synthesis more than women.  Therefore, the anabolic effect of resistance exercise clearly is working through some other mechanism other than spikes in testosterone levels.

My input:  So, men do not have it easier when it comes to weight training anabolic responses.  Both sexes are primed equally for muscle recovery.  The fact that they looked at testosterone comparisons really added to the quality of this study.  It is important to note that the authors are referring to muscle protein synthesis during a recovery phase and not muscle protein synthesis in a long-term muscle building sense.  However, recovery is the first step to adding muscle.

West et al J Appl Physiol. 2012 Jun;112(11):1805-13 

May 10, 2012
The 10-20-30 Training Concept Improves Performance & Health Profile in Moderately Trained Runners

Have a 5K coming up or a race in a track meet?  Would you like to improve your time in the event (wow, it sounds like I’m trying to sell something)?  Well, a group from Denmark just published a paper with an interesting endurance training method to help you reach your new time goal.  This one is for the runners and I assure you I’m not selling anything but exercise.

Introduction:  It is known that people who are already trained need to intensify their training protocols to continue to improve.  Training at maximal or near maximal intensities creates the muscular adaptations necessary for these improvements.  A popular method to do this is introducing 30 second sprint intervals into your training coupled with a short recovery period.  Normally, this is repeated 4-5 times.  However, it is uncertain whether training using just 10 second near maximal sprints has the same effect as the 30 second intervals. In addition, it is unclear whether training at this high of an intensity can affect the health profile of people who are previously trained.  Therefore, the 10-20-30 training concept is introduced and tested to see whether or not it can lead to endurance performance, increases in cardiovascular fitness, as well as health.

Methods:  Eighteen moderately trained individuals (12 males and 6 females) were divided into 2 groups, the 10-20-30 group or a control group.  For a period of 7-weeks, the 10-20-30 group trained with this method whereas the control group continued with their normal weekly training sessions (2-4 times per week, 27km and 137min total).  The 10-20-30 training concept consists of 3-4 x 5 min running interspersed with 2 min of rest.  During the 5 min running period, a person would run 1 min of an interval divided into 30, 20, and 10 seconds at an intensity related to <30%, <60%, and >90-100% of maximal intensity.  They performed this 3 times per week with a volume of 14 km per week.  To test differences in the training methods, the groups performed a 1500m race, a 5-K run, and a running test to exhaustion.

Results (after 7 weeks):

  • The 10-20-30 group improved performance by 6% in the 1500m and 4% in the 5-K run with no difference in the control group.
  • The 10-20-30 group increased their VO2max (maximal oxygen uptake) by 4% with no changes in the control group.
  • The 10-20-30 group lowered their total cholesterol and LDL cholesterol with no changes in the control group.
  • The 10-20-30 group’s systolic blood pressure was lower with no changes in the control group.

Discussion:  After a 7-week period, the 10-20-30 training method, lead to an increase in VO2max of 4% and decreased times on the 1500m by 21 seconds and on the 5-K by 48 seconds.  In regards to health, this training concept also decreased LDL cholesterol as well as resting systolic blood pressure.  This all occurred even though the volume of training reduced by 54%.  One explanation for this by the authors is that high cardiac stress (the max effort 10 second sprints) coupled with a reduction in training volume is sufficient enough to increase VO2max because the group that did the 10-20-30 spent approximately 40% of training time spent above 90% of maximal heart rate whereas the control group spent 0% of training at this level.  For health parameters, the authors also state that the 5 mmHg decrease in systolic blood pressure is of clinically significant because a decrease such as this can reduce the risk of cardiovascular death by 10-15%.

Practicality:  If you were wondering approximate running speeds in case you want to try this out on the treadmill, the 10 second intervals were at speeds >20 km/h, the 20 second intervals were between 10-14 km/h, and the 30 second intervals were <10 km/h.  For those still having trouble understanding the 10-20-30 principle I will give an example:  You would run a warm-up of 5 min at a very low intensity, following this you would begin the 5 minutes interval which is divided into 10-20-30 seconds for each minute.  You run <10 km/h for 30 seconds then right away increase the speed to 10-14 km/h for 20 seconds then again immediately increase the speed to >20 km/h (or as fast as you can run for 10 seconds).  After repeating this another 4 (to make 5 minutes) times you would then have a recovery period of 2 min at a low intensity before repeating the 5 minute intervals 2 or 3 more times.  For those who have tight time schedules, this is practical because all of these improvements with this technique can be accomplished in just 30 minutes.  The authors also state that 10-20-30 is also applicable for anyone who is sedentary up to elite running levels.

Gunnarsson and Bangsbo J Appl Physiol. 2012 May 3

April 26, 2012
Resistance Exercise Load Does Not Determine Hypertrophic Muscle Gains

The Phillips group is back at it again with another great muscle paper that just came out about hypertrophy (gaining muscle mass).  It is not nutrition oriented this time, but instead discusses the amount of weight necessary to stimulate an increase in muscle size.

Introduction:  It has been shown that under an acute exercise bout, using 30% of a person’s 1 rep max (1RM) to the point of muscle fatigue (failure) was equally as effective at stimulating muscle protein synthesis in the muscle fibers as that of loads lifted at 90% of 1RM (also lifted to failure).  This was shown previously by this same group.  Even more intriguing, they found the 30%-1RM condition resulted in a more prolonged muscle protein synthetic response with a greater rise in muscle protein synthesis than the 90% 1RM group 24 hours post-exercise.  Furthermore, other than a relative training load (weight), another important variable for resistance training is volume or the amount of work performed.  The Phillips group also showed before that 3 sets at 70% of 1RM to failure led to greater and a more prolonged muscle protein synthetic rate in the fibers as compared to a single set condition.  However, as I stated, these are all under short-term conditions.  Thus, this new study wishes to see if these hold true under long-term conditions.

Methods:  Eighteen healthy young men underwent 10 weeks of one leg knee extension resistance training where each leg was randomly assigned to one of the three training conditions:  1 set performed to voluntary failure at 80% of 1RM (80%-1), 3 sets performed to the point of fatigue at 80% of 1RM (80%-3), or 3 sets performed to the point of fatigue at 30% of 1RM (30%-3).

Results:  After 10 weeks of training, quadriceps muscle volume increased significantly in all groups and average type I and type II muscle fiber area increased with training (irrespective of training condition with no significant differences between groups).  All three groups also increased their 1RM but it was increased greatest in the 80%-1 & 80%-3 groups.  Total work that could be completed with 80% of the subect’s 1RM increased in all groups and the number of reps that could be performed with 80% of their current 1RM increased in all groups.

Discussion:  The main outcome from this paper is that there was no difference in the magnitude of quadriceps muscle hypertrophy (determined by MRI and muscle fiber area) between legs trained at 30% or 80% of 1RM after 10 weeks of knee-extensor exercise.  Furthermore, there was no statistical difference in the degree of hypertrophy between the 80%-1 and 80%-3 group even though the 3 set group gained a little more volume than the 1 set group.  More interestingly, the 80%-3 and 30%-3 showed more than double the average hypertrophy of the 80%-1 condition.   This adds to the mounting evidence that lifting lighter loads, so long as fatigue is induced, induces roughly equal hypertrophy gains.  It is important to note that both type I and type II fibers increased equally between the heavy and light loads meaning that both fiber types were recruited during the training to an almost equal amount. 

My input:  I can’t preach it enough or put it in bold enough; fatigue, fatigue, fatigue.  Train your muscles till failure.  Don’t worry about the weight on the bar or saving yourself for that last all out set.  Take every set to muscle failure, even beyond with partial repetitions and forced repetitions (if you have a spotter).  I have written it in the past but it needs reemphasized; when training for hypertrophy, the muscle does not “know” the weight on the bar, all it knows is fatigue.  Check your ego, men.  Women too, who use 5 lb dumbbells and do unlimited numbers of reps (you know who you are), aren’t accomplishing anything.  I think it is also important to mention that this study pushes for a volume principle whereas the two groups that completed 3 sets instead of 1 had more muscle volume after the 10 weeks than the group that did only 1 set till failure.  The next plausible step is to see if there is in fact a threshold where doing more sets than 3 will lead to an even greater increase in muscle size (future PhD thesis for anyone that wants to take it).  I would also like to see this study repeated with subjects that are weight trained to eliminate the possibility of a first-time adaptive response to training (another future PhD thesis for anyone that wants to take it).  That could have been the reason why the 1 set to failure condition saw an increase in muscle hypertrophy due to the fact they have not weight trained in over a year.  On the strength side, it also lends to credence to specificity of training in that the leg conditions that used 80% of their 1RM increased their strength more than the group that used only 30%.  If you want to solely increase your strength, focus on using heavier weight, duh.  More long-term studies are needed because a lot of questions can still be asked, but this is already off to a great start when looking at chronic resistance training responses in muscle.

Mitchell et al J Appl Physiol. 2012 Apr 19.

"The last three or four reps is what makes the muscle grow. This area of pain divides the champion from someone else who is not a champion. That’s what most people lack, having the guts to go on and just say they’ll go through the pain no matter what happens."

-Arnold Schwarzenegger

April 18, 2012
H.I.T. and Continued Running Show Similar Skeletal Muscle Responses

You’ve heard the debate before, you know you have.  High intensity interval training (HIT) versus continued steady state running.  Which is better?  A new article has been published showing that when it comes to the two, they may in fact be more similar than we initially thought.

Introduction:  When we talk about adaptations to endurance training, we’re talking about muscle mitochondria.  These adaptations are thought to be turned on by increases in molecular responses from the onset of contraction (e.g. increases in the AMP/ATP ratio, calcium levels, reactive oxygen species, lactate, reduced glycogen availability, etc).  All of these lead to activation of proteins called kinases which phosphorylate targets such as transcription factors or transcriptional coactivators.  Okay, I know, too much science.  It’s gross for you.  Basically, what this means is that these signals increase markers responsible for allowing the mitochondria to adapt to the endurance training and subsequently, you become a better athlete.  However, it is uncertain if there is an optimal exercise stimulus to create these adaptations.  Therefore, the aim of this study was to see the whether or not the signals of these molecular responses after an acute bout of either HIT or continuous running increase greater for one mode of exercise or the other.  The primary hypothesis is that HIT will increase these signals responsible for adaptation to a greater level than that of continuous running.

Methods:  The study recruited 10 recreationally active males who underwent both the HIT and the continued running protocol.  For those unfamiliar with HIT, the protocol was 3-min running at 90% of one’s maximal oxygen uptake followed by a recovery period of 3-min at 50% maximal oxygen uptake (this was repeated 6 times).  The group in the continued running ran the entire time at 70% maximal oxygen uptake.  Muscle biopsies were taken pre-exercise, post-exercise, and 3 hours after exercise.

Results:  Muscle glycogen decreased by 30% in both groups but there was no difference between HIT and continuous running (CONT).  There were increases in all of the molecular markers of mitochondrial content (AMPK, p38MAPK, PGC-1a) in both HIT and CONT but again, no differences between the two modes.

Discussion/Conclusion:  This is the first study to demonstrate that both HIT and continuous running induce comparable responses of molecular markers in muscle.  The authors state that this could be due to both protocols being relatively intense since there is only a difference of 20% maximal oxygen uptake between the two groups.  Another first-time discovery of this study was an increase in stress proteins in response to HIT training indicating a stress response on the body (although this was not significant).

My input:  The main power of this study is that the even though the 2 groups performed different types of endurance training, the researchers matched the groups to perform the same intensity, duration, and work performed.  Without doing that, it would have been very difficult for them to conclude that HIT and continuous running show similar molecular responses.  It bothers me that the intervals were not the usual ones prescribed for exercise protocols in studies (4-6 times of 30 seconds all out cycling/sprinting).  My only critique comes with the time.  When matching for time, the HIT group exercised for 18 min of sprinting and 18 min of recovery plus a warm up and cool down period totaling 50 min.  The continuous running group did 50 minutes without a warm up and cool down.  If they took the biopsies after the sprints were finished and not after a cool down, they may have seen responses similar to what they hypothesized.  It is also worth mentioning that this study is short-term and it is not yet known the responses to long-term endurance training of this variety.  Other than that, this is the first study to show that following a short bout of endurance exercise, there are similar responses in the mitochondrial of muscle between both HIT and continuous running.  It seems that for now, both are sufficient in making you a better athlete.  

Bartlett et al J Appl Physiol. 2012 Apr;112(7):1135-43

April 12, 2012
That would be whey better than leucine. Supplement companies aren’t going to like me.

Whey protein or leucine post-workout to increase muscle protein synthesis (MPS)?  The Phillips group just published an article trying to answer this question. 

Introduction:  You all are probably aware that ingesting amino acids stimulates an increase in muscle protein synthesis even without resistance training.  Leucine has been toted to best stimulate MPS by activating components of a signalling cascade known as mTOR.  There is still controversy though as to whether or not leucine can enhance MPS following leucine infusion or by simply adding more of it to a post-workout protein drink.  This group previously reported the the optimal dose of protein post-workout to stimulate MPS was 20g and that anything below this is not sufficient and anything above this number (40g) does not increase MPS further.  Therefore, the aim of this study was to see if taking a “sub-optimal” dose of whey (6.25g with approximately 0.75g of leucine) protein and supplementing it with leucine or a mixture of essential amino acids without leucine would have an effect on MPS at rest and after acute resistance training.  This will be compared to a dose of whey (25g with approximately 3.0g of leucine) which is sufficient to induce maximal stimulation of MPS after resistance exercise.

Methods:  Twenty-four adult males were randomized to one of three groups that either ingested a whey protein drink, a leucine drink, or an essential amino acid drink.  Prior to ingestion, the volunteers completed an acute bout of unilateral resistance exercise (knee extensions).  Muscle biopsies were taken at the time of ingestion and at time points 1 hour, 3 hours, and 5 hours post-exercise.

Results:  After whey protein ingestion, blood leucine, branch-chain amino acids, essential amino acids, and total amino acids were all highest as compared to the groups that ingested leucine or EAA (without leucine).  Blood leucine was only higher initially after ingesting the leucine drink but stayed elevated longer by ingesting whey.  Rates of MPS remained increased for 3-5 hours at exercise recovery above those volunteers who did not ingest anything, versus the groups who ingested leucine or the EAA drink.

Discussion:  A dose of whey protein that has been previously shown to be less than maximally effective to stimulate MPS after resistance exercise, when supplemented with leucine, resulted in an early (1-3 hour post-exercise recovery) increase in rates of MPS equal to that of ingesting 25g of whey.  Also, the same was found by supplementing a low dose of whey with essential amino acids void of leucine.  However, MPS was sustained longer (3-5 hours post-exercise) only with the group that ingested whey protein.  These differences occurred despite the fact that blood amino acid levels returned to baseline after 3-5 hours but MPS still continued.  Therefore, the authors state that peak activation of MPS does not appear to be driven by increasing leucine in the blood and that amino acid transport across the sarcolemma (plasma membrance of the muscle cell) and intracellular amino acid availability may be important in the regulation of MPS.

Conclusion:  Leucine stimulates MPS post-exercise equal to that of whey protein, despite only containing 45% of the total EAA content of the whey.  However, similar increases in MPS were observed in the EAA ingestion group that did not contain leucine.  Thus, the authors speculate that in young healthy individuals, the leucine content provided by approximately 6.25g (approximately 0.75g of leucine) of whey protein seems adequate to maximally stimulate MPS if sufficient amounts if the other EAA are provided (approximately 8.5g EAA).  Also, the whey protein ingestion group was the only group that sustained MPS 3-5 hours post-exercise.

My input/practicality:  What if I were to tell you I can make a 1lb bag of whey protein last me 3 months?   Well I can, and I do, and I’ve been doing it for years.  I only use a half scoop of whey protein post-exercise.  Never a full scoop.  Never a “heaping” scoop.  Why do you even think they use the word heaping? It’s all about the dolla dolla bill y’all.  This study shows that only 6.25g of whey is necessary to maximally stimulate protein synthesis as long as it contains approximately 750mg of leucine and 8.5g of the other 8 essential amino acids (which are histidine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine).  Make sure you check on the labels of your favorite whey protein because it usually lists the amount of leucine and the other essential amino acids on it.  One scoop of whey is usually on average around 20g of protein so if you use a half scoop like me it is around 10g (still a little over from what this study suggests).  Supplement companies are going to hate this study (like they read them anyways) as well as me for posting this but you’ll love it/me for saving you money.

Churchward-Venne et al J Physiol. 2012 Mar 25.