2009 Studies & Research Blog

Note: The following study was performed with SciVation Xtend as the source of BCAAs.

A randomized, double-blind study was performed to evaluate the efficacy of consuming a supplement containing branched-chain amino acids (BCAAs) during an eight-week resistance-training program.

Thirty-six strength-trained males with a minimum of two years resistance-training experience (25.5 yrs, 177.7 cm, 85.2 kg and 9.3 % body fat) were randomly assigned to receive either 14 grams of BCAAs (n=12), 28 grams of whey protein (n=12), or 28 grams of carbohydrates from a sports drink (n=12) while performing an eight-week resistance-training program.

Participants followed a periodized, whole-body training program that involved training all major muscle groups once per week using a four-day training split. Subjects body weight, body composition, and 10-rep max on the bench press and squat were determined before and after the eight-week training program. Subjects followed a standardized diet while following the program.

All groups had a 100% compliance with the study protocol. The BCAA group experienced a significantly greater gain in body weight than the whey group (2 ± 1 kg vs. 1 ± 1 kg; p < 0.02) and the carbohydrate group (2 ± 1 kg vs. 1 ± 1 kg; p < 0.01). For lean mass, the BCAA group gained significantly greater lean mass than the whey group (4 ± 1 kg vs. 2 ± 1 kg; p < 0.01) and the carbohydrate group (4 ± 1 kg vs. 1 ± 1 kg; p < 0.01).

The whey group also gained significantly more lean mass than the carbohydrate group (2 ± 1 kg vs. 1 ± 1 kg; p < 0.02). BCAA group decreased their percent body fat significantly more than the whey group (2 ± 1 % vs. 1 ± 1 %; p = 0.039) and the carbohydrate group (2 ± 1 % vs. 1 ± 1 %; p < 0.01).

Muscular strength was significantly greater in the BCAA group on the 10-RM bench press than the whey group (6 ± 3 kg vs. 3 ± 2 kg; p < 0.01) and the carbohydrate group (6 ± 3 kg vs. 2 ± 2 kg; p < 0.01). For the squat, the BCAA group gained significantly more strength on their 10-RM than the whey group (11 ± 5 kg vs. 5 ± 3 kg; p < 0.01) and the carbohydrate group (11 ± 5 kg vs. 3 ± 2 kg; p < 0.01).

Ingestion of a supplement containing BCAAs while following an 8-week resistance training program resulted in a greater decrease in percent body fat, an increase in lean mass, and 10-RM strength gains on the bench press and squat vs. ingestion of a whey supplement or a sports drink. In addition, the ingestion of a whey protein supplement resulted in greater lean mass gains than ingestion of a sports drink.

Check out Bodybuilding.com’s full line of BCAAs right here.

Those familiar with the supplement industry are aware that most supplements are grouped into general categories, according to their supposed effects.  A few of the most popular groups are supplements intended to increase lean mass, those intended to decrease body fat, and those to increase strength.  And while many supplements concern themselves with one or maybe two of these categories, a multi-purpose supplement that targeted all three would be ideal.  According to recent research, that supplement might be HMB.

You’re probably wondering - what is HMB?  Good question.  HMB stands for beta-hydroxy-beta-methylbutyrate, which is a metabolite of leucine, an essential amino acid.  While it does naturally occur in certain foods, including alfalfa and catfish, some have surmised that supplementing HMB might be beneficial (1).

The first study investigating the effects of HMB on body composition and strength in conjunction with exercise was conducted in 2000.  While the study only lasted four weeks, the benefits of HMB were clear.  Groups receiving HMB supplementation experienced two times the reduction in body fat that the placebo group experienced.   The HMB group also experienced greater lean mass gains and strength.  The researchers concluded that "regardless of gender or training status, HMB may increase upper body strength and minimize muscle damage when combined with an exercise program" (2).

A study published this month in the Journal of Strength and Conditioning Research took the prior research a step further, investigating HMB’s effects throughout a nine-week exercise program.  The researchers noted that earlier research had not considered the effects on "resistance-trained" individuals, which may have accounted for the impressive results in past studies.  To counter this, the study participants were required to have at least one year of weight training experience.  The average level of experience was 3.9 years, suggesting that any growth from the study would be a direct result of the HMB, rather than so-called "noob gains" (3).

The findings of the study in regard to strength gains were curious; while one-repetition maximum in the leg extension increased by 9.1 percent on average, its effect on upper body strength was negligible.  The researchers did note, though that it was "possible that the 9-week study period was not long enough to establish the effect of HMB on gains in strength" (3)

The HMB supplementation seemed to have a greater effect in regard to body composition, though, as the HMB group members experienced a mean decrease in body fat percentage of 7 percent, while the placebo group only had a 1 percent decrease.  Additionally, the HMB group experienced greater gains in lean body mass than the placebo group (3).

So is HMB the ultimate supplement?  Not quite.  While it did boost strength it some lifts, it generated only negligible differences in others.  But it also had a positive effect on lean mass and body composition, so it may still be worth a look.  The researchers also noted that HMB seemed to be "more efficacious to individuals initiating resistance training programs and, possibly, also in less well-trained muscle groups," so more experienced lifters may not see the same benefits (3).

SOURCES:

1. HMB Supplement Review - BodyBuilding For You: http://www.bodybuildingforyou.com/supplements-reviews/hmb-supplement-review.htm

2. Panton, Lynn B., et al. Nutritional supplementation of the leucine metabolite ?-hydroxy-?-methylbutyrate (hmb) during resistance training.  Nutrition, 2000; 16(9): 734-739

3. Thomson, Jasmine S., Waston, Patricia E., and Rowlands, David S. Effects of Nine Weeks of ?-hydroxy-?-methylbutyrate Supplementation on Strength and Body Composition in Resistance Trained Men.  The Journal of Strength and Conditioning Research, 2009; 23(3): 827-835

Getting the right exercises, total set number, and number of reps in your workout is going to be vital so that you see continued results.  Far too often though people overlook the factor of tempo.  How fast or how slowly you lift a given weight will have a direct influence on how you progress as well, as it will factor into the total intensity of the weight lifting program.

As you may have already found out for yourself if you’ve experimented with different tempos, lifting a weight at a much slower pace does tend to be significantly more difficult than lifting it at the typical moderate pace instead.

Recently, researchers out of the Waseda University wanted to assess tempo and the resulting hormonal responses different protocols obtained.

The design of the study was set up so that nine men would perform knee extension exercises.  On one occurrence they would perform these at a low-intensity with a clow concentric contraction, with a rate of 5:1 seconds on the concentric to eccentric phase.  

On the second occurrence they would perform similar low-intensity exercise with slow eccentric contractions, reversing the ratio to 1:5 seconds for the up and down motion.

On the third trial, they were to maintain similar timing for both the eccentric and concentric contractions, with a 3:3 ratio.  

Finally, on the fourth trial they performed high-intensity exercise at the normal velocity of 1:1 for contraction speed.

After each trial the subjects were tested for lactate concentration, plasma ephinephrine, serum growth hormone, and free testosterone levels.  

The results of the study indicated that the lactate concentration in the body was significantly higher after the 5:1 exercise compared to the 1:5 exercise.  The slow movement exercises also showed a much higher level of serum growth hormone and free testosterone concentration compared to the faster paced tempo.  One interesting thing to note was that serum cortisol level was higher after the 5:1 tempo compared with the 1:5 or 1:1 tempo.

From this data we can conclude that there are some positive muscle building correlations between performing slower weight lifting contractions, however to avoid higher cortisol levels throughout the body you would be better off not just focusing on slowing down the concentric portions of the movement.

Reference:
Goto, K, et al. (2009) Hormonal and metabolic responses to slow movement resistance exercise with different durations of concentric and eccentric actions.  European Journal of Applied Physiology. May 10.

Whenever you perform a resistance training workout, there is going to be some degree of development of blood lactate levels in the body. When lactic acid develops in the muscle tissue in response to high intensity activities, feelings of fatigue begin to set in and very often exercise performance will cease (when the situation is extreme enough).

Recently researchers wanted to look at how the factor of time under tension impacted the blood lactate response during different types of resistance training protocols with regards to the degree of muscle size and strength that was developed.

They had 12 recreationally trained young men perform four variations of workouts using the knee extension machine, with the four different workout protocols consisting of:

1 – super slow training: one repetition performed over 60 seconds with 30 seconds for the concentric portion and 30 seconds for the eccentric portion

2 – functional isometrics: one five second maximal contraction with the knee fully extended

3 – adapted vascular occlusion: 20 second maximal isometric contraction with the knees fully extended and then immediately going into a normal rep procedure

4 – a set of 10 RM

The results of the study indicated that all the protocols produced significant increases in blood lactate levels, however the response during workout variation 2 was higher than variation 1.  

The researchers also noted that time under tension was highest for group 1, 2 and 3 compared to those performing the 10 RM.  

From these results, researchers concluded that the super slow training protocol may not be your best bet if you want to achieve a high metabolic stimulus, but instead the functional isometrics training method (group 3) is a better option.

Reference:

Bottaro, M. et al. (2006) Time under tension and blood lactate response during four different resistance training methods.  Journal of physiological anthropology. Sep;25(5):339-44.

Across the world of fitness, it is widely accepted that nutrition plays a key role in the success of any body transformation plan, whether it is to gain muscle or lose fat.  Of particular interest is the post-workout period, often referred to as the "anabolic window," or the "window of opportunity."

Both supplement companies and scientific studies concentrate on the intake of nutrients after the completion of a workout.  The actual dimensions of this window are under constant construction, with some arguing that immediate feeding is imperative, while others claim that waiting a certain amount of time is preferable.

With all this fuss about the post-workout period, though, it almost seems as if no other meal matters.  This is an assumption that can have costly consequences.  The body recovers and builds muscle around the clock, not just during an effervescent window of anabolism directly following a workout.  In fact, several studies have suggested that pre-workout nutrition may even be more important than post.

In a study that featured a mix of healthy young men and women, researchers compared the effects of whey protein supplementation either immediately before exercise or after the workout.  While one of the popular justifications for the importance of post-workout nutrition is the insulin spike that supposedly drives protein into muscle cells, the researchers found there was not a significant difference between insulin levels of the pre-workout group and the post-workout group (1).

But that wasn’t the only myth of post-workout nutrition superiority busted in this study.  The researchers also investigated the anabolic response in each of the groups.  Contrary to what most might expect, the anabolic response to the whey protein ingestion did not differ significantly between the groups.  Additionally, intra-cellular amino acid concentrations and amino acid uptake levels did not suggest an advantage to either of the ingestion periods (1).

In effect, the study suggests that in regard to pertinent factors, consuming protein during the "anabolic window" is not the be-all and end-all of workout nutrition.  However, it should be noted that the study did not indicate that post-workout nutrition was not beneficial.

For many, eating post-workout provides a valuable source of calories to contribute to the surplus needed for muscle growth.  Additionally, data from this study showed that amino acid delivery was higher compared to rest for in both pre- and post-workout groups (1), so it is unlikely that a post-workout feeding is going to do more harm than good.

SOURCES:

Tipton, Kevin D., et al. Stimulation of Net Muscle Protein Synthesis by Whey Protein Ingestion Before and After Exercise.  American Journal of Physiology - Endocrinology and Metabolism, 2007; 292: 71-76

In the realm of pre-, intra-, and post-workout nutrition, many athletes tend to argue over the effectiveness of carbohydrates and protein, but often place the two macronutrients in opposition to one another.  A common belief is that heavy concentrations of pre- and intra-workout carbohydrates are only appropriate for endurance sessions, while protein should be the primary concern of shorter bouts, usually those consisting of resistance training.  Even many supplement companies seem to follow this line of thinking, offering pre- or intra-workout supplements consisting of either primarily carbohydrates (often with an energy booster such as caffeine) or protein (in the form of EAAs or BCAAs).  While those arguments may have logical foundation, scientific data points to a different conclusion - that the combination of carbohydrates and protein are more effective than either in isolation.

When you think about it, this shouldn’t seem like a difficult concept to believe.  The powerful combination of carbohydrates and protein is widely accepted as the most effective means of post-workout nutrition, even for those following low-carbohydrate diets.  And just this year, researchers have found experimental evidence that the one-two punch of carbohydrates and protein is optimal for intra-workout nutrition as well.

The study compared the performance of athletes, supplied with either a carbohydrate beverage or a carbohydrate and protein beverage, during two 60-km time trials.  The average time for completion was significantly lower in the carbohydrate and protein group, with the time difference usually supplied by superior performance in the final 20 km (1).  But this study did more than indicate that the carbohydrate-protein combination was effective for endurance activities.

Levels of plasma creatine phosphokinase, a marker of muscle breakdown also decreased in the carbohydrate-protein group.  Additionally, the researchers noted that "muscle-soreness ratings increased significantly" following the carbohydrate only trial, while this trend was not apparent in the carbohydrate and protein trial (1). Such measures would surely be of interest to those performing resistance exercise.

While more research on this subject could undoubtedly provide some additional information of interest, the existing literature does indicate that combining carbohydrates and protein in intra-workout nutrition is beneficial.  What a great example of teamwork.

SOURCES:

1. Saunders, Michael J., et al. Carbohydrate and Protein Hydrosylate Coingestion’s Improvement of Late-Exercise Time-Trial Performance.  International Journal of Sports Nutrition and Exercise Metabolism: 2009; 19: 136-149

Common sense, as well as scientific studies, have established that pre- and post-workout nutrition are essential components to a training program.  Supplying your body with the fuel and the nutrients it needs before any type of exercise allows you to perform at a higher level.  Likewise, re-fueling tired muscles, reversing catabolism and initiating anabolism with a post-workout feeding benefits the pursuit of muscle mass.

Recently, intra-workout supplementation has gained popularity in the bodybuilding community.  The consumption of Branched Chain Amino Acids (BCAAs), as well as Citrulline Malate and even whey protein during lifting sessions is now commonplace.  However, it seems that intra-workout carbohydrate supplementation is less popular.  This is a shame, because carbohydrates can have beneficial effects when taken during training.

One study analzyed the performance of cyclists with or without the supplementation of carbohydrates.  The researchers found that cortisol levels were reduced, and time-trial performance improved, during trials with carbohydrate supplementation.  Interestingly, fat oxidation was significantly increased when carbohydrates and caffeine were supplemented together during the trials (1).

Critics of intra-workout carbohydrate supplementation argue that it reduces the body’s ability to burn fat during exercise.  However, research has shown that this is not necessarily the case.  Levels of fat oxidation were not significantly different and researchers concluded that during "moderate-intensity exercise," the feeding didn’t "suppress fat oxidation" (2).

Additionally, carbohydrates play a vital role when supplementing amino acids during exercise.  Researchers have noted that carbohydrates assist in "potentiating protein balance" and can help "meet the fuel needs of the working muscles."  Furthermore, carbohydrate consumption, with or without BCAA supplementation, "provides an effective strategy against both peripheral and central mechanisms of fatigue" (3).

Still, many critics will point out that the majority of the studies on this subject relate to endurance exercise.  However, research on carbohydrate supplementation has been tested in other athletic events, such as soccer, as well (3).

If you do choose to supplement carbohydrates during training, dosage is an important consideration.  Obviously, consuming too many calories during any kind of exercise will counteract the effects of the activity.  However, studies have indicated that 20 grams of carbohydrates can be oxidized in one hour of exercise.  While you may still be skeptical of carbohydrate ingestion for shorter workouts, researchers advised that during longer training sessions, there is "no doubt" that carbohydrates should be supplemented (4).

In the end, the decision whether or not to take in carbohydrates during training is up to you.  You should consider how these calories will fit into your overall fitness plan, and whether the duration and intensity of your training calls for additional nutrition.

SOURCES:

1. Slivka, Dustin, et al. Effects of Caffeine and Carbohydrate Use on Exercise Performance, Substrate Oxidation and Salivary Cortisol. Medicine & Science in Sports & Exercise, 2008; 40(5): S361.

2. Civitarese, Anthony E., et al. Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes. American Journal of Physiology, Endocrinology and Metabolism, 2005; 289: E1023-E1029.

3. Burke, Louise M. Branched-Chain Amino Acids (BCAAs) and Athletic Performance. International Sports Medicine Journal, 2001; 2(3): 1-7.

4. Dennis, S.C., et al. Nutritional strategies to minimize fatigue during prolonged exercise: Fluid, electrolyte and energy replacement. Journal of Sports Sciences, 1997; 15(3): 305-313.

One problem that plagues many athletes, especially those who are participating in longer endurance running events is that of muscle cramping, particularly in the abdominal region.  Some people refer to these as ‘side stitches’ other simply call them cramps – whatever you want to call them though, one thing is certain and that is that they can severely debilitate your performance.  In most cases, they will actually cause you to cease movement and you may have to walk or just stand until the cramp goes away.

But, what causes these cramps in the first place? One common thought is that ingestion of fluids will increase your likelihood of developing stomach cramps, and because of this, many people find themselves staying away from drinking too much before they go out for a run. Is this necessary?

Researchers out of the Avondale Centre for Exercise Science in Australia had a look at this exact issue in a study they conducted that investigated the effect of ingested fluid composition on abdominal pain.

They had forty subjects who had previously complained about cramps during exercise complete four different treadmill exercise trials.  These trials consisted of a no-fluid trial, a flavoured water trial (no carbohydrate content, 48 mosmol/L, pH 3.3), a sports drink trial (6% carbohydrate, 295 mosmol/L, pH 3.3), and finally, fruit juice (10.4% total carbohydrate, 489 mosmol/L, pH 3.2).

After each beverage was taken and the corresponding exercise completed, the measures of gastrointestinal disturbances, with particular attention being paid to bloating were assessed.

The results indicated that the fruit juice had a much higher chance to cause muscular cramps in the abdominal region as well as bloating in comparison to the other three test trials, with no difference being seen between the no-fluid, flavoured water, or sports drink beverages.

These results then indicate that if you’re looking to avoid stomach cramping problems during exercise, it would be a smart idea to avoid fruit juices or other beverages that have a higher carbohydrate content and osmolality before you partake in physical exercise.

Reference:

Aragon-Vargas LF, et al. (2004). Effect of ingested fluid composition on exercise-related transient abdominal pain. Int Journal Sports Nutrition and Exercise Metabolism. April; 14(2):197-208.

With all the many different training methods available, there are plenty of options with regards to how you can go about designing your training program.  Depending on your individual goals, certain exercises will be much more beneficial than others, so it’s always vital to look at programs within the context of your goals.

If your goal happens to be speed-strength or sprint oriented one technique that is starting to gain some attention as a training mechanism is whole body vibration training.  Recently, researchers out of the Faculty of Health and Environmental Sciences in Auckland, New Zealand looked at whether vibration training could enhance strength, power, or speed of athletes using it.

In their study, they noted that the vibration training did cause an increase in the g-forces acting on the muscles, which increased the loading parameters of the exercise.  Due to this increased loading, they concluded that this should also help to increase the total muscle hypertrophy and could possibly even increase neuromuscular potentiation.

One thing the authors of the study did notice though was that the vibration training did not seem to do a great deal for the speed of the athletes, so the effects seen were more noticed with regards to maximal speed and power.

Another previous study that looked at whole body vibration training was published in the International Journal of Sports Medicine back in 2005. During this study, twenty experienced sprint trained athletes were randomly assigned to a whole body vibration training group or a control group during a 5 week training period.  All the athletes kept up with their regular workout programs however the vibration training group also underwent a three times a week vibration training protocol, consisting of unloaded static and dynamic leg exercises on a vibration platform.

The vibration training consisted of unloaded static and dynamic leg exercises on a vibration platform along with pre and post isometric and dynamic knee extensor and flexor exercises on a motor-driven dynamometer.  

The results of this study were not quite the same in that no differences in vertical jump or sprint running velocity were seen.  

Therefore, the take home message for you is that you may want to look into trying different training methods to augment your goals such as whole body vibration training, but the most significant progress with results is still likely going to come from more traditional training techniques that have been proved time and time again to increase strength, speed, and jumping ability.

References:

Harris, N. et al. (2009) Vibration training: could it enhance the strength, power, or speed of athletes? J Strength Conditioning Research. Auckland, New Zealand. Mar; 23(2):593-603.

Dairy farmers have been saying it for years - milk does a body good.  The seemingly innocuous beverage, though, has touched off heated controversy in the bodybuilding community, with some swearing by it and others demonizing the drink.  While the average non-athlete may depend on milk for a boost of protein in perhaps a less than ideal diet, most bodybuilders consume more than enough protein on a daily basis to satisfy their needs.  So what’s the big deal with dairy?

According to recent research, there’s a lot at stake - specifically, improved performance and an accelerated metabolism.  Given these scientific results, it seems foolish not to incorporate some milk into your diet.

The main complaint with many studies, specifically those involving protein intake, is that they don’t relate to weight lifting or athletic performance in general.  This research is different.  The first study, published in [i]Applied Physiology, Nutrition and Metabolism[/i], dealt with the consumption of milk-based proteins in the post-workout period.  The participants were all athletes and divided into four groups.  All groups completed a bout of exercise and then were given one of four possible drinks: water, low-fat milk, a chocolate milkshake drink, or a sports beverage consisting of maltodextrin and glucose (similar to Gatorade).

Unsurprisingly, the groups that consumed the chocolate milkshake drink and the low-fat milk showed significantly higher levels of peak torque and total work capacity within 48 hours after exercise.  Interestingly, though, the protein content alone wasn’t the deciding factor of the effectiveness of the recovery beverage.  The chocolate milkshake, with 33 grams of protein, 118 grams of carbohydrates and 16 grams of fat, provided better recovery than the low-fat milk, which contained 34 grams of protein, 49 grams of carbohydrates and 17 grams of fat.  Also worth noting is that both drinks had significant levels of fat, which is usually frowned upon during the post-workout period.  Despite the fat content, peak torque and total work capacity did not suffer dramatically(1).

But milk’s positive effects aren’t merely limited to recovery.  Another study compared the effects of two diets with differing amounts of casein protein in them.  Casein has gained popularity in the bodybuilding community for being a slow-digesting protein source and is easily derived from milk.  But even though it digests slowly, casein appeared to play a role in speeding up subject’s metabolisms, as the study found that the group consuming 25% of their calories from casein had a greater energy expenditures, sleeping metabolism rates and feelings of satiety (2).  This indicates that milk can play a valuable role in dieting.

Whether one is trying to pack on muscle or shed fat, milk can be a very valuable, and cost-effective, supplement.  Bottoms up!

SOURCES:

1. Cockburn, Emma et al. Acute Milk-Based Protein-CHO Supplementation Attenuates Exercise-Induced Muscle Damage. [i]Applied Physiology, Nutrition and Metabolism[/i]. 33: 775-783 (2008)

2. Hochstenbach-Waelen, Ananda et al. Comparison of Two Diets with either 25% or 10% Energy as Casein on Energy Expenditure, Substrate Balance, and Apetite Profile. [i]American Journal of Clinical Nutrition[/i]. 89: 1-8 (2009)

For many people out there looking for fat loss, the low carb diet offers many promising benefits.  They experience decreased hunger, steadier levels of energy throughout the day, and often have a much easier time bringing their calories lower, hence they can see faster success while on the diet.

But, with low carb diets, one thing you need to be aware of is the fact that there are implications when it comes to exercise performance.  Since the body is primarily going to run on carbohydrates during exercise (stored muscle glycogen and glucose in the blood stream), when these are brought down very low, high intensity exercise is going to be harder to maintain, so measures need to be taken to adjust the workout program.

On top of that, there are also hormonal changes that will take place while on a lower carb diet, so making yourself aware of these will be important too.

Researchers out of the Department of Applied Physiology in Warsaw, Poland conducted a study where they assessed what types of implications occurred when a severely carbohydrate restricted diet was introduced with respects to exercise intensity as well as the hormonal response to exercise itself.

The researchers set out to study the changes in plasma adrenaline, noradrenaline, growth hormone, testosterone, and blood lactate levels while the subjects were to perform incremental exercise until exhaustion for three days in a row.  During this time, they followed either a very low carbohydrate diet, consisting of less than 5% of total energy coming from carbohydrates, or else followed an isocaloric mixed diet.  

The results of the study indicated that in the subjects following the L-CHO diet, the basal plasma adrenaline, noradrenaline, and growth hormone concentrations were increased, but testosterone and blood lactate levels were decreased.

During the exercise session all the hormones were increased, but the pattern of hormone changes in the body were not altered by the low carb diet apart from noradrenaline, which was decreased.

So, the overall results of the study indicated that low-carbohydrate diets are mostly going to exert their effects on decreasing the noradrenaline threshold, which will cause an increase in the sensitivity of the sympathetic nervous system when exercising.  This then could potentially alter the basal and exercise levels of hormones that determine whether the body is in a catabolic or anabolic state.

Therefore, the take home message for you is that while low carbohydrate diets may pose to be a good idea when trying to lose fat, for muscle building, you should likely reconsider.

Reference:
Kaciuba-Uscilko, H. et al. (2001). The effect of low-carbohydrate diet on the pattern of hormonal changes during incremental, graded exercise in young men.  International Journal of Sports Nutrition and Exercise Metabolism. Jun;11(2):248-57.

In the pursuit of muscle, body builders are constantly on the lookout for new ways to increase the intensity of their workouts.  After all, pushing the limits of what the body is capable of is what this sport is all about.  As a result of this mindset, performing exercises until failure is a popular way attempt to maximize mass.  Some studies have shown, though, that this method is not appropriate in all circumstances.  When used effectively though, it can help you propel your physique to the next level.

As the name implies, training until failure is an exhausting undertaking.  So if you’re going to make use of it, you’ll want to make sure you’re getting the most out of it.  It’s important to note that short-term failure training is not always preferable.  This discovery was made during an 11-week study of a group of men, each with at least four years of recreational lifting experience.  The subjects were divided into two groups, with a "Failure" group performing three sets of the leg curl, leg extension and squat until failure, while the "Nonfailure" group performed four sets of these exercises, never reaching failure.

The results were somewhat surprising.  While both groups experienced significant increases in strength throughout the study, there were no differences between the groups in terms of 15-repetition max or total work performed.  The researchers noted that the "total volume of training" appeared more important in regard to muscular endurance than "whether workout sets are performed to failure."  Moreover, they concluded that "when intensity and volume are equated, failure or nonfailure training results in similar gains (1)."

But training to failure is far from useless.  In fact, the lead author of the aforementioned study suggested that such training protocol could be very effective in programs "structured for increases in strength and hypertrophy."  He noted that failure training could be the key to breaking through plateaus. This conclusion was based upon research in which failure training was incorporated occasionally.

When the technique was adopted as part of a six-week cycle, it "resulted in superior increases in strength and hypertrophy in both untrained subjects and elite athletes."  The success of failure training lies in its ability to induce greater stimulation in the highest threshold fast-twitch muscle fibers.  It should be noted that in contrast, the "highest threshold motor units may never be fully recruited" through non-failure training (2).

Obviously, training to failure is very strenuous on the body and should not implemented all of the time.  When used sparingly, and strategically, though, this technique can promote growth unlike any other.

SOURCES:

1. Willardson, Jeffrey M., et al. Effect of Short-Term Failure Versus Nonfailure Training on Lower Body Muscular Endurance. International Journal of Sports Physiology & Performance: Sep 2008, Vol. 3 Issue 3: p279.

2. Willardson, Jeffrey M. The Application of Training To Failure in Periodized Multiple-Set Resistance Exercise Programs. Journal of Strength & Conditioning Research: May 2007, Vol. 21 Issue 2: p628.