Category: Triathlon Training

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Endurance Training – Avoiding the no man’s land

endurance training - Endurance Training - Avoiding the no man's landLatest research indicates that over 90% of our endurance training should be done at a pace so slow that we feel almost “guilty”, with only around 3% going really hard and very little in the so called “tempo”  (no man’s land) zone… Mike

How a train low, train high approach can lead to increased performance

endurance training1 - Endurance Training - Avoiding the no man's land

In recent years, the ‘middle way’ has been a popular mantra of politicians. However, as Joe Beer explains, when it comes to training intensity in endurance sports such as cycling and triathlon, the middle way is most definitely not the most effective route to elite performance

Professional elite athletes know how to train because they have access to the best coaches and a because of the Darwinian process that ‘kills off’ bad methods and keeps good ones thriving! However, until very recently, the amateurs have never had access to the facilities and coaching backup of elite performers, so more often than not they have tended to source information from the best athletes they know locally and/or the group ethos prevailing in their particular training group or environment. The problem with this approach is that the ‘sheep mentality’ of merely doing what everyone else does is not especially effective. And let’s be honest, sheep don’t win many athletic medals!

Peaks in the clouds

Athletes used to look to the top of the sports mountain, shrouded in the clouds of greatness, and wonder what went on up there. Take, for example, the secret regimes of the 1980s ‘doctors’  behind the Iron Curtain, possessed of the ability to increase team performances in track, field and cycling. Nowadays, we have greatly increased transparency with more and more data from individuals, teams and countries, and from journals and interviews. From 4km cycling powerhouses (1) to elite junior rowers (2), as well as many others, data is published for all to see. Thankfully, we can now see that the gains are less about pharmacology and more about the analysis of training, outcomes and lessons learned.

For example, the prologue ride of cyclist Bradley Wiggins in this year’s Tour De France was online within days so that cycling fans could swoon over the his super-human effort – an average power output of 442 watts. Wiggins also published blood test data to counter any suspicion that he must have been on ‘something special’ to get fourth place overall. However, that’s a separate article entirely about champion genetics, weight loss and superb equipment choices.

Fortunately, this new openness gives sports scientists, coaches and amateur athletes the chance to see how the best actually train, and most importantly for you, it allows a trickle down of certain ‘golden nuggets’ of information from upon high. Think of it in the same way that steering wheel control paddles trickled down from rallying and F1 racing to your family car.

So it was fascinating when recent data were presented in the International Journal of Sports Physiology and Performance on 36 elite junior rowers’ actual training data(2). These data will rock the training methods of some and give the thumbs up to what others are already doing. What they suggest in a nutshell is that the ‘Goldilocks’ approach to training (not too hard, not too easy) is detrimental for optimum performance, resulting in a no man’s land of not much progress.

endurance training2 - Endurance Training - Avoiding the no man's land

Standing on the shoulders of giants

Researchers in Germany have looked at the training and competition data of elite rowers with national, world and Olympic rowing performance capabilities. Over a 37-week period, training was quantified methodically using heart rate monitoring, assessment of lactate threshold points (the point at which fatiguing lactate begins to accumulate rapidly in the blood) and performance outcomes. The rowers (14 of whom went onto Olympic finals), were lab tested to find critical points of blood lactate concentration in order to define certain training zones. These have been discussed previously in PP (see issue 239) and are shown below:

While you probably won’t have a blood lactate tester to hand, it’s quite easy to get a feel for the 2 and 4mmol/L levels. Below 2mmol/L of lactate, there’s no burning sensation and heart rates are around 60-75% of maximum. Between 2 and 4mmol/L, blood lactate builds and declines, never quite bringing you to your knees but you definitely get a sense of a ‘workout’. Above 4mmol/L, (sometimes referred to as the ‘lactate or anaerobic threshold’), exercise feels very hard, and in fact rowing data suggests that 6-8mmol/L is often reached in training by elite rowers. This high-intensity effort is such that once under way, you hope it ends very quickly! Typically, it involves from around 40 seconds to 8 minutes of maximal effort (2).

When the researchers analysed the 37-week data, their findings were very interesting. One of the most important of these was that internationally successful junior rowers performed 95% of all specific rowing training at a heart rate corresponding to a blood lactate concentration under 2mmol/L (see figure 1).

endurance training3 - Endurance Training - Avoiding the no man's land

Within the average 12-14 hours of training per week the athletes logged over the scrutinised period, this meant six hours of actual rowing in Zone 1 (Z1). Two to three hours were spent resistance training, two hours doing alternative steady state aerobic training, and one hour doing warm-up/flexibility work. Given that this data covered the competition period, it is very, very important to note that the athletes did just 30 minutes a week of very high intensity work.

The real world

Many endurance athletes do events that, in the real world, typically last from 15 to 20 minutes and upward. These include 5K road races, 10-mile time trials and sprint triathlons. Few actually compete in events as short as the rowers tested, though anyone in an event lasting over 40 seconds is really an endurance athlete. Many people are now entering ultra-endurance triathlons such as the Ironman where finish times are 9 to 17 hours. Similarly, sportive cycle events lasting 4 to 10 hours are attracting record numbers. How should these athletes train?

From earlier work on rowers (3), the importance of training below the anaerobic threshold has been steadily gaining attention; and anaerobic thresholds are increasingly being used as a diagnostic tool rather than a training method. In short, the anaerobic threshold is not the Mecca of training effort; it’s merely one of the many ways used to measure an improvement or decline in fitness capability. Trying to train at threshold is not the way to train: you are working too hard to be easy and too easy to be properly hard!

As respected cycling journalist and coach Fred Matheny put it almost 15 years ago in an article in Bicycling: ‘NML (no man’s land) workouts provide a kinaesthetic sense of working hard but expose the rider to too much stress per unit gain. Instead most base training should be guilt-producingly easy, and the top end, high-intensity-training (HIT) should be very mentally hard, not sort of hard’ (4).

Rowing quality sessions

Lets look at what the rowers in this study did for quality (3). Over the study period, they averaged just 2-3% of their time performing very high intensity efforts. In distance terms they did 73km in the tempo zone (Z2) but just over 3200km in Z1. Although 2000m rowing requires just 6-7 minutes of maximal effort, they still focused on ‘very easy’ or ‘very hard’.

Examples of these high-intensity sessions included:

  • 2-3 x 3-10 mins @ 90% HRmax – 10-20 mins recovery between;
  • 2-8 x 40-120 sec @ maximal effort – 5-15 mins recovery between.

In order to be ready for this very high level of effort, you need to ensure you’ve done your base sessions in a controlled manner. The priority is being ready to do the hard work, not making endurance sessions harder than they need to be. Far too many athletes try to push the base and then fail to go really hard for their HIT training.

Why does train low, train high work?

How is it that large amounts of low-intensity work can develop base conditioning, aid recovery from HIT sessions yet not turn an athlete into a ‘plodder’, churning out ‘junk miles’? Well, first off if you do your base work in the 60-80% HRmax zone, you will get as fit and efficient as your genetics will allow for that particular training mode.

However, you can’t turn base work into quality – it can be good quality technical work and it can be good quality tempo of movement, but it can’t be harder than the Z1 upper threshold. If you train in Z1 consistently, allow recovery and have no major health issues, your body will reach around 90% of its potential – no tempo work, no HIT and relatively little effort. Although you may feel guilty, easy training can get you 9/10ths of the way to your peak potential!
You can train excessively in the tempo ‘no man’s land’ zone for years. But while it gives you a buzz from your workouts and gets reasonable performances, the inputs verses the outputs never match up. For example, if you train over 15 hours per week but include more than 25% of your training in Z2 ‘no man’s land’, you’ll fail to get better despite logging more time than others who do mostly Z1 and are improving. Remember the phrase ‘guilt-producingly easy’ for more than 90% of your week, especially if you’ve been someone who has always trained too hard up until now. Figure 2 shows how elite athletes across a range of sports spend most of their time in zone 1.

endurance training4 - Endurance Training - Avoiding the no man's land

For many athletes, the ‘train low, train high’ mantra requires a mindset change, forcing them to think about things differently. Perceptions such as ‘base is easy now’, ‘I can relax knowing I don’t have to keep up with other people’ or ‘It’s now more enjoyable but also more effective’, are typical when people finally get what the elites already know.

Summary

Whatever endurance athlete type you are, train low, train high can work for you. This does not mean ‘go easy, we don’t want to push ourselves do we?’ Inclusion of the very high intensity (Z3) work is absolutely critical. However, for long-term success, you need to construct your training so that the body can evolve in a very patient way. Many athletes, even with the best coaching, only see on average a 2 to 8% improvement in a given year, especially those who’ve got several racing seasons under their belts already. If you’ve been struggling in no man’s land and not making much progress, try using train low, train high approach and set realistic improvements of say 5% (not 10 or 15%) faster for 2010. And if you remember the valuable three golden nuggets above, better times are ahead.

Joe Beer is an endurance coach working with cyclists, triathletes, duathletes and runners through his company JBST.com. He is also the author of ‘Need to Know Triathlon’ (Harper Collins)

References

1. Med. Sci Sports Exerc. (2002) 34, 6, 1029-1036
2. IJSPP (2009), http://tinyurl.com/kwe26d (in press)
3. Int. J Sports Med. (1993) 14, S3-S10
4. Bicycling Oct (1995) p.90
5. J Strength Cond Res. (2007) 21, 3, 943-949
6. Scand J Med Sci Sports (2004) 16, 49-56
7. Scand J Med Sci Sports (2004) 14, 303-310
8. Med. Sci Sports Exerc. (2005) 37, 3, 496-504
9. Scand J Med Sci Sports (2003) 13, 185-193

This article was taken from the Peak Performance newsletter, the number one source of sports science, training and research. Click here to access these articles as soon as they are released to maximise your performance


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Triathlon Training – Managing Arrhythmia Part 3

The final piece of the puzzle drops into place…

racing saddle - Triathlon Training - Managing Arrhythmia Part 3Well listen up guys and dolls, this is serious stuff that effects all of you! Your sexual health could be at great great risk because of the saddle you use!

On an annual basis, bicycle riding involves several hundred million people worldwide. Studies have linked perineal pressure caused by straddling traditional bicycle seats to numbness, urinary tract and yeast infections, prostate inflammation and impotence.

For male riders, in addition to the discomfort and numbness associated with a traditional saddle, there is an increased susceptibility to restricted blood flow, which can lead to arterial occlusion and permanent erectile dysfunction.

For women, the restricted blood flow and hardening of the genital arteries can lead to an inability to reach orgasm. It has been found that as little as 11% of a person’s body weight can compress the genital artery!

So what has  a bike saddle got to do with my arrhythmia?

This perineal pressure and it’s damaging effect, is far greater for triathletes in the aero position, and although I have had minor prostate issues for many years, it was under control and only became severely aggravated after I started triathlon training and riding a bike just over two years ago.

As outlined in my earlier blog post Triathlon Training – Killing Six Birds With One Stone, it is my enlarged prostrate that prohibited the emptying of my bladder, which then got me up every hour at night to go to the loo, which then prevented me getting sufficient rest to recover from training, which then lead to my being in an overtrained state, which then lead to severely aggravated heart arrhythmia!

…so amazingly it actually all started with the bike saddle!

The traditional bike saddle shape has in effect changed very little since the original “Penny Farthing” of yesteryear, but thank goodness at least one innovative manufacturer has at last taken the matter seriously enough to do the necessary research and develop a new design that completely handles the problem:-

adamo saddle - Triathlon Training - Managing Arrhythmia Part 3ISM Adamo Saddles

Here’s an interesting read on the health benefits of no nose saddles vs. traditional saddles.

On September 5, 2006 Steve Toll traveled to the University of Hamburg to have the new Adamo Road saddle and the Adamo Racing saddle tested by noted German urologist Dr. Frank Sommer. At the conclusion of the testing Dr. Sommer was pleased with the results and congratulated Steve on his design and achievements. Dr. Sommer stated, “A saddle where there is hardly any blood loss. Which is excellent to preserve sexuality and for preventing erectile dysfunction.”

While normal testing involves a 15-minute ride on a saddle, the test using the ISM™ was discontinued after 12 minutes.  Why?  Dr. Sommer commented, “It doesn’t get any better than this.”  In fact, blood flow in the perineum area remained at 100% throughout the test with the ISM™, a mark rarely seen in bicycle saddle testing.

In addition, Dr. Sommer’s prior research has indicated that some saddles restrict blood flow in the perineum area by as much as 95% within the first minute of a ride.  Other studies indicate that such restriction over a long period can result in permanent erectile damage.

The ISM™ is a first-of-its-kind seat.  If a family is in your future, or you’re simply tired of the pain and discomfort associated with a traditional saddle, rest your bones on the ISM™.  It’s medically better for you.

Adamo saddles are currently available from Troisport (best price), Wayne Pheiffer and Triangle Sports in South Africa, so get one now as besides anything else your butt is going to thank you big time!

I will never ride again with any other…

Articles

NIOSH (National Institute for Occupational Safety & Health) Update

National Geographic Adventure, April 2003 – Riding Rough: New Evidence Continues to
Link Biking to Impotence by Jim Thornton.

Bicycling Magazine, August 1997 – The Unseen Danger by Joe Kita

Other Research Studies: Available Through the National Library of Medicine

“Impotence and Nerve Entrapment in Long Distance Amateur Cyclist”
Andersen K.V., Bovim G.
Laboratory of Clinical Neurophysiology, Trondheim University Hospital, Norway.

“Does Bicycling Contribute to the Risk of Erectile Dysfunction?”
Goldstein I., Marceau L., Kleinman K., McKinlay J.

“Type of Saddle and Sitting Position Influence Penile Oxygen Pressure while Cycling“
Dr. Frank Sommer, Cologne University, March 2003.

“Pressure Distribution on Bicycle Saddles” (a comparison between normal “flat” saddles
with gel and saddles with a “hole” in the perineal area)
Renato Rodano, Roberto Squadrone, Massimiliano Sacchi, Alberto Marzegan
Centro di Bioingegneria, Milan, Italy – November 2002.

“Ergonomics of 2 Bicycle Saddles” (Pressure at the Pudendal Area in Women of a
Normal Saddle with Gel and of a Saddle with a Hole)
Dr. Ingo Froboese – Deutsche Sporthochschule, Cologne, Germany
Dr. Luc Baeyens – Centre Hospitalier Universitaire Brugmann, Brussels, Belgium.

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Sports nutrition – A training strategy for protein consumption

A comprehensive and well researched article for those who want to optimise their nutrition to maximise performance which could give them the edge over their competition. Mike.

There is more to protein intake than simply eating the right amount

There’s more to protein nutrition than just eating the optimum amount; the timing of consumption and the type of protein selected can both impact on nitrogen balance; and there are a number of nutritional ‘co-factors’ that are either essential or useful in promoting optimum protein metabolism within the body.

This is especially true where carbohydrate is concerned, because building or even maintaining lean tissue mass is an ‘energy-intensive’ process. Increasing protein intake at the expense of carbohydrate can be a bad strategy for athletes engaged in heavy training, because without sufficient carbohydrate the body simply switches to other fuels for energy, and amino acids from protein (particularly the branched chain amino acids, leucine, isoleucine and valine) provide a ready source of energy!

Muscle tissue is a relatively rich source of branched chain amino acids (BCAAs), and tends to undergo breakdown during periods of highenergy demand, when carbohydrate and/or the amino acid pool becomes depleted. Furthermore, carbohydrates stimulate the release of insulin, a highly anabolic hormone, which helps to drive both glucose and amino acids into muscle cells. Any athlete seeking to optimise his or her protein metabolism should therefore ensure a carbohydrate intake commensurate with training volume.

Protein-carbohydrate mixes

The role of carbohydrate in enhancing endurance during long events and accelerating post- exercise recovery is undisputed, and new research (highlighted in PP 194, March 2004) indicates that carbohydrate feeding before and during high intensity exercise can limit the amount of stress hormone release, thereby reducing the risk of post-exercise immune suppression. However, research suggests that protein has a role to play, too. A study on resistance training examined hormonal responses to water, carbohydrate, protein or a carbohydrate/protein mix, given immediately and then two hours after a training session. As expected, those fed the carbohydrate and carbohydrate-plus-protein mix drinks showed an increased insulin response.

However, those fed the carbohydrate-protein mix also showed a modest but significant increase in growth hormone levels, suggesting that protein combined with carbohydrate following resistance training may create a more favourable hormonal environment for muscle growth.

Post-exercise protein feeding seems to be beneficial for endurance athletes also. In a study on 40 swimmers given either water or water-plusglucose during training sessions and then either water, sucrose or a sucrose-plus-milk protein mix after training, the subjects receiving the posttraining sucrose-protein mix exhibited lower levels of creatine phosphokinase (a marker of muscle damage) than the others. Moreover, creatine phosphokinase levels returned to baseline levels more rapidly in this group, indicating that the ingestion of protein with carbohydrate accelerates recovery.

A study on ultra-endurance athletes, published just a few months ago, showed that a carbohydrate-protein mix maintained a positive nitrogen balance during and after a six-hour training session (five hours of cycling and one hour of running), while a straight carbohydrate drink did not.

The consensus of scientific opinion now is that, following intense exercise, athletes should ingest a carbohydrate and protein mix (around 1 gram per kg of body mass of carbohydrate and 0.5g per kg of protein) within 30 min of completing exercise, as well as consuming a high-carbohydrate meal within two hours. This nutritional strategy has been found to accelerate glycogen resynthesis as well as promoting a more anabolic hormonal profile that may hasten recovery.

Research carried out over a decade ago indicated that ingesting a light carbohydrate/ protein snack 30-60 minutes before exercise is also beneficial. In these studies it was shown that 50g of carbohydrate and 5-10g of protein, taken before a training session, could increase carbohydrate availability towards the end of an intense exercise bout and also enhance the availability of amino acids to muscles, thereby decreasing exercise-induced catabolism (breakdown) of protein.

This research appears to be backed up by a very recent study carried out on 15 trained cyclists, who cycled to exhaustion on two rides 12-15 hours apart, the first at 75% and the second at 85% of VO2max. During the test, riders were split into two groups and given either a 7.3% carbohydrate drink (1.8ml per kg every 15 minutes), or the same drink with protein added at 1.8%. After 7-14 days, the test was repeated and the drink protocol reversed.

The results showed that riders taking the carbohydrate-plus-protein rode for 29% longer than the carbohydrate-only group during the first (75% VO2max) ride and 40% longer during the second (85% VO2max) ride! Furthermore, peak levels of creatine phosphokinase were 83% lower when carbohydrate plus protein was taken. Since the carbohydrate plus protein drink contained 25% more calories overall, further studies are needed to see how much of this effect is due to higher energy intake. However, it seems reasonable to assume that a carbohydrate-protein drink taken during training provides for increased protein concentration outside the cell, which can potentially enhance protein synthesis and repair.

The concept of different glycaemic indexes (the rate at which digested carbohydrate is released into the bloodstream as glucose) for different carbohydrates is now well accepted. However, different proteins display different rates of breakdown into their amino acid building block constituents, and hence uptake into the body.

A study into whey protein and casein (two types of protein supplements that are popular with athletes and bodybuilders) examined the speed at which one of the amino acids (leucine) appeared in the bloodstream after ingestion of a meal of each kind of protein (containing identical amounts of leucine). The researchers found that whey led to a dramatic but short-term increase in plasma amino acids, while casein induced a prolonged plateau of moderately increased levels.

They concluded that the differences were probably explained by the slower gastric emptying of casein. Whey protein is a soluble protein whereas casein clots into the stomach, so delaying its gastric emptying. Likewise, soy protein appears to be digested more rapidly than milk protein, resulting in a higher but more transient peak of plasma amino acids.

The implications are obvious: an athlete seeking to supply a post-training or mid-training boost to the amino acid blood pool would be best advised to consume a fast-release protein, such as whey or soy. However, when a prolonged period of recovery is in store (eg at bedtime) a slowerreleasing casein protein drink, such as milk, would be better. Another implication of this study is that, providing a meal or drink supplies the same quantity of the essential amino acids, one type of protein is not necessarily ‘better’ than another. Of more importance is that its release rate is matched to the timing of ingestion.

The situation also appears to be complicated by age. A recent study, which looked at the effects of protein retention in young men (mean age 25 years) fed protein meals containing either slow-releasing casein proteins or rapid-releasing whey proteins, found a greater retention (ie uptake into muscles) after casein. However, when the same researchers studied protein retention in elderly subjects (mean age 72 years), their findings were reversed, with whey protein producing a significantly higher uptake of amino acids than casein.

The researchers surmised that amino acid availability may limit muscle synthesis in older subjects, and that the higher amino acid peaks produced by whey prevented this from happening. The implication seems to be that ingesting fast-releasing proteins mid- or postexercise may be more important for older athletes than their more youthful counterparts.

‘Free form’ amino acids

The process of digestion releases the amino acid building blocks from ingested protein. However, as we’ve seen, this release rate is variable and the process of digestion itself actually consumes energy. This has prompted some investigators to ask whether the use of ‘free form’ amino acids before, during or after training could be a rapid method of providing athletes with optimum amounts of amino acids exactly when they’re needed.

Particular interest has been shown in the branched chain amino acids (BCAAs), which are readily oxidised for energy and therefore in greater demand when energy output is high. In theory, BCAA supplementation might help to minimise protein degradation, thereby leading to greater gains in fat-free mass, or at least minimise lean tissue loss when training volumes are high.

BCAAs and body composition

There is some evidence to support this hypothesis; for example, a study conducted on trekkers at altitude found that taking 10g of BCAAs per day during a 21-day trek increased fat-free mass by approximately 1.5%, while controls on placebo experienced no such change. Meanwhile, another study found that 30 days of BCAA supplementation (14g per day) promoted a significant increase in muscle mass (+1.3%) and grip strength (+8.1%) in untrained subjects.

These findings suggest that BCAA supplementation may have some impact on body composition. Moreover, some recent evidence suggests that BCAA supplementation can decrease exercise-induced protein degradation and/or muscle enzyme release (an indicator of muscle damage), possibly by promoting an anticatabolic hormonal profile(. However, despite the persuasive rationale, the effects of BCAA supplementation on short- and long-term exercise performance are somewhat mixed, with some studies suggesting an improvement and others showing no effect. More research is needed, therefore, before firm conclusions can be drawn.

Having said that, there is good evidence that BCAAs administered during training can reduce the perception of fatigue, while improving mood and cognitive performance. A study on seven male endurance-trained cyclists with depleted glycogen stores examined the effects of BCAA supplementation (versus placebo) on mental fatigue and perceived exertion. The subjects exercised at a work rate corresponding to approximately 70% VO2max for 60 minutes, followed by another 20 minutes of maximal exercise.

During the 60-minute section, the subjects’ ratings of perceived exertion were 7% lower and mental fatigue 15% lower when they were given BCAAs. In addition, cognitive performance in the ‘Stroops Colour Word Test’ performed after exercise was improved when BCAAs had been ingested during exercise. Interestingly, however, there was no difference in physical performance in the final 20-minute segment of the ride between the placebo and BCAA groups; the amount of work performed during this section was the same regardless of which supplement was taken.

These findings on BCAA supplementation, mental fatigue and perceived exertion were replicated in a study on runners given carbohydrate-plus-BCAA drinks or carbohydrateonly drinks (placebo) during a 30k cross-country run. Subjects on BCAAs improved their postexercise performance in the above-mentioned Stroops test by an average of 3-7% compared with those on placebo. The BCAA group also maintained their performance in two more complex mental tasks (shape rotation and figure identification) after exercise, while the placebo group showed a 25% and 15% reduction respectively in these tasks.

Researchers believe that this cognitive effect may be due to the ability of BCAAs to compete with and therefore reduce the uptake of another amino acid, tryptophan, across the blood-brain barrier and into the brain. Tryptophan is the precursor to a brain neurotransmitter called 5- hydroxytryptamine (5-HT – more commonly known as serotonin), which is involved in fatigue and sleep and is believed to contribute to the development of central/mental fatigue during and after sustained exercise. During exercise, the concentration of tryptophan in the blood relative to other neutral amino acids seems to rise. But supplementing with BCAAs seems to help block this effect, which would, in turn, reduce levels of 5- HT in the brain.

Is leucine a ‘special-case’ BCAA?

Leucine is the most studied of the BCAAs, partly because leucine and its metabolites have been reported to inhibit protein degradation (22). In the body, leucine accounts for about 4.6% of all amino acids and is involved in many important roles in the body, such as regulating protein metabolism by inhibiting degradation and stimulating synthesis .

Of particular interest is the fact that leucine can be oxidised to a compound known as acetylCoA in muscles at a higher rate than the other BCAAs (valine and isoleucine). This is important because acetylCoA is an ‘entry point’ into the citric acid cycle, one of the main energy-producing pathways in the body, and itself the gateway to aerobic metabolism, which explains why the demands for leucine rise substantially during periods of high energy expenditure. Studies have also shown that leucine oxidation is increased under catabolic conditions, such as depleted muscle glycogen.

Some researchers believe that the current leucine requirement, set at 14mg per kg of body weight per day, should be increased to 30mg in people who regularly participate in endurance activities. This argument is supported by research that suggests endurance athletes can actually burn more leucine than they take in through the RDA of protein.

One of the best-known leucine metabolites is a compound called ß-hydroxy ß-methylbutyrate, Is leucine a ‘special-case’ BCAA? more commonly known as HMB, which is popular with bodybuilders and athletes as a muscle/strength building supplement. But what is the evidence that it actually works? Recent research indicates that 1.5-3g per day of HMB supplementation can increase muscle mass and strength, particularly in untrained subjects beginning training and in the elderly. The muscle mass gains in these studies are typically 0.5-1kg greater than for controls during 3-6 weeks of training.

There is also recent evidence that, in athletes, HMB may reduce the catabolic effects of prolonged exercise. In one study, 13 runners were split into two groups, one taking 3g of HMB per day and the other a placebo. Both groups continued with their normal training for six weeks, after which they completed a 20k run. Before and after the run, creatine phosphokinase and lactate dehydrogenase levels (both measures of muscle damage) were measured, with the HMB group showing much smaller increases in both than the placebo group, indicating significantly reduced muscle damage.

However, the long-term effects of HMB supplementation in athletes are less clear. Most studies conducted on trained subjects have reported non-significant gains in muscle mass(34-36), but further research is needed to clarify whether HMB really does enhance training adaptations in athletes.

Essential amino acids

The BCAAs comprise just three of the nine essential amino acids (EAAs), the other six being histidine, lysine, methionine, phenylalanine, threonine and tryptophan. As mentioned, essential amino acids have to be obtained from the diet because they can’t be synthesised in the body from other amino acids. Although the six ‘straight chain’ EAAs are not so readily utilised as fuel, some researchers believe that giving all nine EAAs in a free form (ie as a mix of separate amino acids, not as protein), and in ratios that reflect the amino acid composition of muscle protein, is more beneficial for muscle protein synthesis than giving BCAAs alone.

In recent studies, scientists in Texas have found that ingesting 3-6g of EAAs before and/or after exercise stimulates protein synthesis. Moreover, this stimulation appeared to increase in a dose-dependent manner until plasma EAA concentrations are doubled, and was maximised when EAAs were administered to maintain this doubled concentration over a three-hour period. Adding carbohydrate seemed to enhance this protein synthesis, probably through the anabolic effect of insulin.

Although there has been very little research on EAA ingestion by athletes, studies on resistance training in healthy adults seem to confirm the potential benefits of EAAs; for example, muscle protein synthesis was increased 3.5-fold when 6g of a mixture of EAAs was given along with 35g of carbohydrate after resistance exercise.

In another study, three men and three women resistance trained on three separate occasions and then consumed, in random order, one of the following:

  • a 1 litre solution of mixed amino acids containing both essential and nonessential amino acids (40g);
  • a solution containing only essential amino acids (40g);
  • placebo.

Net muscle protein balance was negative after ingesting placebo but positive to a similar magnitude for both the mixed and essential amino acid drinks. The researchers concluded that: ‘it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise’.

A comprehensive protein strategy

Given the above findings, what reasonable steps can an athlete take to optimise his or her protein nutrition? Below is a ‘protein checklist’, which crystallises these findings into dietary recommendations:

  • Ensure an adequate intake of dietary protein – ie a minimum of 1.5g of high-quality protein per kg of body weight per day. Power/strength athletes, or those engaged in intense training, should consider increasing this to 2g per kg per day;
  • Ingest protein-carbohydrate drinks after exercise rather than protein alone. Ideally, consume a drink made up of about 1g per kg of carbohydrate and 0.5g per kg of protein within 30 minutes of training, and eat a high-carbohydrate meal within two hours;
  • Consume a light pre-exercise snack: 50g of carbohydrate and 5-10g of protein taken before a training session can increase carbohydrate availability towards the end of an intense exercise bout and also increase the availability of amino acids to muscles. However, make sure your snacks are low in fat to allow for rapid gastric emptying!
  • Use protein/carbohydrate drinks during very long events: a solution containing 73g carbohydrate and 18g protein per litre, consumed at a rate of 1ml per kg of body weight per minute, may delay the onset of fatigue and reduce muscle damage;
  • Consume quick-digesting proteins such as soy and whey immediately after training: this may be especially important for older athletes;
  • At other meals, consume a mix of proteins in order to promote a more sustained release of amino acids into the body;
  • Adding BCAAs to your normal protein intake may be useful for athletes undergoing prolonged or heavy training, and this may be particularly true for events/sports requiring large amounts of mental agility and motor coordination;
  • HMB supplementation, at 3g per day, may be a useful additional strategy for novice athletes, or those returning to training after a layoff;
  • Essential amino acid blends taken 1-3 hours after training may promote additional muscle protein synthesis, although this hypothesis is not proven in athletes;
  • Don’t forget to ensure that your overall diet is of high quality and as whole and unprocessed as possible: this will ensure adequate intakes of other nutrients essential for protein metabolism, such as zinc and the B vitamins.

Andrew Hamilton

References

  1. J Appl Physiol, 2003; 548P, 98
  2. J Appl Physiol, 2003; 94:1917-25
  3. J Appl Physiol, 1994; 76:839-45
  4. Eur J Appl Physiol Occup Physiol, 1992; 63:210-5
  5. Am J Physiol Endocrinol Metab 2004; 287:E712- E720
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