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Fat Could Make you Faster, Science Says

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We took a stab at debunking one myth – dehydration and exercise and performance. Time to take a swing at another. Fat burning at high exercise intensity.

To steal a phrase from our New Zealand colleagues, WTF? (What The Fat)!?

Our question: could fat burning be more critical for high-intensity performance than previously thought?

Background

Physiologists have long known that fat fuels us at rest and even for low to moderate exercise intensities. Beyond this point, however, we’ve been told that fat’s contribution diminishes towards negligible values as exercise approaches maximum levels – when we’re in the ‘red zone’.

The classic textbook shot here (below) for reference. This is what we teach and learn.

For high-intensity exercise performance, it makes sense that carbohydrate oxidation is essential. Put simply, we get a higher rate of ATP (energy) per unit of oxygen uptake per unit of time. More energy means better performance capacity.

The question: is fat oxidation at high exercise intensity really negligible? Does it actually turn off? Does it play a negligible role for athletes competing in short (<8min) high-intensity Olympic-type sports?

To answer, we need to get at more detail to understand the issues. As a starting point, I’ve shown Figure 1 from Jeukendrup & Wallace (2005), which takes various studies to show nicely the different factors (training status, exercise mode, gender and diet) that influence the relative degree of carb and fat oxidation with exercise intensity (x-axes).

The most important point that we usually take from these examples is that which is shown from the textbook example above; that calculated fat oxidation becomes negligible at high exercise intensities, reaching zero it seems once exercise intensity reaches values ranging from 75-90% of VO2max. Right at the spot where most athletes need to compete.

Is that really the case? Is it all about carbohydrates for high-intensity exercise, or is it possible that fat oxidation could also be important? How do we begin to get insight into the question?

If you want to follow what we’ve done in the forthcoming study, we need to dive into more detail.

Indirect Calorimetry Substrate Estimates

Substrate oxidation (carb and fat burning) is estimated using gas exchange measurements from a metabolic cart (right) and stoichiometric equation calculations. This technique, known as indirect calorimetry, is thought to be the gold standard technique for measuring this.

Let’s take a basic look at how it is calculated.

Inside the cells of the body needing energy, we know that the reactions converting the substrates carbohydrate (glucose) and fat (palmitate).
Glucose oxidisation:

 

 

Palmitate (fat) oxidisation:

 

 

We’ll skip a few details to get to the heart of the matter, but basically, because the oxidation of those substrates have different O2 and CO2 inputs and outputs, it winds up that the CO2 you exhale relative to the O2 you take in, gives us a ratio (VCO2/VO2) number from our metabolic cart data ranging from 0.70 to 1.00, termed the RQ (respiratory quotient), or RER (respiratory exchange ratio). When that ratio number reads 0.70, it tells us we are burning pure fat. When it reads 1.00, it tells us we are burning pure carbohydrate. So by using this method, we can estimate the relative quantities of carbohydrate and fat being oxidized at a given exercise intensity. That’s how the various graphs above shown by Jeukendrup & Wallace (2005) are being calculated.

Limitations

But this estimation has one important limitation related to the current topic. While it’s mentioned in the Jeukendrup & Wallace paper and others, I don’t believe this point has been well-discussed or researched to date. The point is this: When we exceed our threshold intensity (maximal lactate steady state), a shift in acid-base balance occurs. With increased required carb burning (anaerobic glycolysis), lactate accumulation in the contracting muscle moves into the blood and increases the acid content [H+] (likely related to that burn you feel with hard exercise), which is buffered predominantly by the main buffer in your blood, bicarbonate [HCO3-] (see schematic from Marieb, 2009). This excess (non-oxidative) CO2 is then added to the total VCO2, making our VCO2 amount larger than it would have been had the acid not been added to the mix when we crossed the threshold.

The regulation of this buffering system and its various players are shown.

 

How does the Acid Load Affect the RQ and Carb/Fat Determination with Exercise?

As you’ve probably gathered, the higher lactic acid-induced production of CO2 [through HCO3- buffering] has a large influence on the calculation of carbohydrate and fat oxidation. It creates an overestimation of the carb burning amount and an underestimation of the fat burning. The estimation of fat use with these equations goes so low in fact that it often becomes zero, and then negative. Of course, we can’t report a negative number, so scientists typically present their data up to the point where it becomes zero, and not beyond. See again those Jeukendrup & Wallace (2005) examples above.

Given these challenges, the contribution of fat metabolism to energy demand during high-intensity exercise is less studied.

Our Study

What did we do? Or more accurately, what did our Norwegian colleagues that ran the study do? The details are for all to read in our recently published open access BMJ article. This research group, Ken Hetlelid, Eva Herold, and Stephen Seiler, took nine well-trained male runners with big engines (VO2max 71 ± 5 ml/kg/min) and compared their substrate oxidation responses during interval training with nine recreationally trained runners (VO2max 55 ± 5 ml/kg/min).

Methods

The recreational runners were active in a variety of sports, performing endurance-type training 2-4 times per week, while the well-trained running group included regional level distance runners and national level orienteers training 6 to 10 sessions per week. All runners were using typical western diets (relatively high carb).

Both groups of runners performed a high-intensity interval training (HIT) session, and indirect calorimetry, as described, along with heart rate, blood lactate and rating of perceived exertion (RPE) were measured. The HIT session, performed on a treadmill up a 5% gradient, was self-paced and consisted of six, 4-min work bouts separated by 2-min recovery periods.

Results

Both groups of runners performed the HIT session at the same level of RPE and blood lactate level. That means generally that the effort felt the same for both groups. The self-paced HIT session was, of course, run faster for the well-trained guys (15 vs. 11 km/h roughly), and that difference in running speed (figure right) was explained by higher absolute and relative oxygen uptake levels (figure below), and calculated energy expenditure. You’d expect that.

 

But if we dig a bit deeper, let’s uncover WHY it was faster, and WHY the well-trained guys were able to get at more energy. Check out the data below.

 

Here’s why…

It wasn’t the carbohydrate oxidation. That was identical in both groups (unclear; right), just like its end product (lactate) was.

It was the fat…

The fat oxidation, at those high exercise intensities, was nearly 3 times greater in the well-trained runners compared to the recreationally trained (right and above figures). It wasn’t zero, or negligible, as we are often told, but in fact accounted for 33% of the total energy expenditure in the well-trained guys over the sequence of high-intensity intervals.

Not only was fat oxidation 3 times greater – Fat oxidation at high intensity looks like it was the key discriminating factor explaining performance in the interval set between the two groups. It was the main why. Something happened with training it seemed to allow more fat oxidation at high exercise intensities.

 

 

The new findings didn’t end there…

Fat oxidation didn’t just explain HIT performance. It also explained VO2max – that gold standard marker of fitness and performance we often hear about. When we lined up all the subjects in the study and compared their VO2max with their average carbohydrate and fat oxidation rates during the HIT session, it was the average fat oxidation rate during the HIT session that very highly explained VO2max. Carbohydrate rate, though unclear, actually trended the opposite direction.

Considerations

Our study brings forth a number of points we need to consider.

  1. Typical less trained response. First observation. Check out the fat oxidation line for both groups of runners as they progress through their interval session. Notice how the less trained group has the typical response we see reported (typical volunteer subject group doing university degrees). Notice their negative fat oxidation values, especially during the recovery phases, as bicarb buffers the sugar-burning acid release. But certainly a different response for our better fat burning well-trained guys.
  2. Underestimation, not an overestimation of fat oxidation. Recall the bicarb issue previously mentioned. That blood buffer creates its bias towards the overestimation of carbohydrate oxidation and the underestimation of fat oxidation. So fat oxidation at the muscle level is likely higher than what we report here. You can’t say our study is not valid because of the bicarb issue – it biases our estimates in favour of carbs, not fat.
  3. Self-paced HIT session vs. completely all out. It’s important to appreciate that we have a self-paced intermittent high-intensity exercise situation, and not a near all-out 2K rowing race that might be performed at an even higher exercise intensity. So our situation gives us more potential for greater fat utilization. Both groups performed their prescribed intervals just above the second ventilatory turn point (VT2) identified during preliminary testing. But this is a high intensity right around the range that many scientific spokespersons (usually supported by an industry we all love) are claiming no benefit of fat oxidation.

But no benefit? Negligible?

To us, it doesn’t make much sense that fat oxidation would become zero at high exercise intensities. I remember giving first-year lectures in my days and we often started with a video called “All systems go”. Its not the most exciting piece of work, but can be seen here.

 

The gist of the video was that all energy systems contribute to ATP production all the time. In this example, we were talking the ATP-PC system, anaerobic glycolysis, and the aerobic system. Not on and off like a light switch, but all on in different proportions, at different times. Likewise, isn’t it logical to think that the lipolytic (fat) system would still be functioning in the background to contribute to ATP provision during high-intensity exercise as needed? Our study, albeit just one, suggests this may be the key factor that changes with training status.

Why does our Study Matter?

Interpretation of science to date has been that carbohydrate oxidation dominates and is the only substrate of importance for high-intensity exercise. Practice in nutrition logically follows. As an example, we recently attended the ECSS Congress and watched a Gatorade-spokesperson tell us that fat metabolism at high exercise intensity is not discussed, because “it doesn’t play a role during high-intensity exercise”. Let’s hope our study is the beginning of further work in this area.

To summarise, the new findings from our study are

  1. Well-trained and recreationally trained athletes performed a HIT session with similar levels of RPE, blood lactate, and carbohydrate oxidation.
  2. Well-trained runners oxidized nearly three times more fat than recreationally trained athletes during their HIT session.
  3. Fitness (i.e., VO2max) and the capacity to perform high-intensity intermittent work was mostly explained by the higher fat oxidation rates at high-intensity.

In our next post, we’ll talk about why it makes sense that fat oxidative capacity at high exercise intensity should be a key high-intensity performance factor.

Having been involved in elite competitve triathlon from a very early age, the area of performance and individual improvement has always intrigued me. As I've grown and gone through various experiments on myself and in the lab, I've realised that much of what we've been taught is false.

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Training

How to Build Strength on the Bike

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Taking a break from triathlon over the winter months? Put this time to good use and learn how to build strength and power on the bike.

How do I build strength on the bike? This is probably the question I get asked the most as a coach, and it’s the toughest to answer – especially when dealing with time-poor athletes, as biking is so time-consuming and few of us have the time to tap out two-to-three hour rides in the hills each day to gain the necessary strength needed to improve our ironman or half-ironman bike time.

As a pro athlete, it’s quite easy to lay down a strength-specific bike block to top things up if needed, which generally takes four-to-five weeks of specific work, provided the athlete has a good five-year base behind them. As an age grouper though, a 600-kilometre strength-focused week is not realistic. So, how do you build strength from a 200-kilometre bike week?

This is a tough proposition, but here are a few tips to increase your strength and hopefully improve your bike time. I am not saying that you will be pushing a 58-tooth chainring and riding at 45km/ph, but even if we’re just squeezing a small amount of juice from the orange, we are still getting somewhere.

Hill reps

This is probably the best way to increase strength. It is the most used and the most uncomfortable – but generally, the sessions that you find the most uncomfortable are the most beneficial. I see hill reps as the paddles/band session you do in swimming converted to cycling. Both sessions add specific stress on certain muscle groups of the body that are critical to the areas that need to be worked.

Much like this swim session will add stress to the shoulders/back/core, strength sessions on the bike will increase the work on the glutes and hamstrings, which is where the main power on the bike comes from. In saying this, when doing strength efforts it’s important to stay seated and place the chain ring in a large gear (one that is hard to pedal). If you have a cadence meter on your bike computer you will want to see around 60-to-70 RPMs on it while you are in the saddle. A gradual climb of around two-to-three kilometres is perfect for this session and should be completed two-to-three times with a submaximal heart rate of around 70 percent of your maximum. This effort should not be a lung-busting torture test, as it’s not designed to stress the cardio system but to build the muscular and central nervous system.

Gym

Hit the gym for an extended period of time during a break in racing and focus on specific muscle groups like the glutes, hamstrings and lower back. Not only will this assist with the increase in power development but also, perhaps, more importantly, it will help in the prevention of injury through strengthening the associated tendons and connective tissue around the muscle groups. This type of program should only be attempted after a consultation with a qualified coach or PT who can guide you through these exercises and ensure they are done correctly. I am a big believer in the benefits of a well-constructed and consistent weights program periodised with a structured program within the training phases.

Trainer sessions

Most people refer to these as the Devil. They are widely detested, particularly by athletes with sadistic coaches who program two-to-three hour solo sessions on the machine. As for strength benefit, these sessions are great as strength endurance sessions and can be added in if you find it hard to get to the hills. Just drop the gear down, stay in the saddle, and get the heart rate into the zone that you need.

Generally, trainer sets are a strength session in and of themselves as there is no freewheeling, no traffic lights and no downhills so you are constantly placing power down in a consistent manner. So, if you are time poor, increase your trainer sets during the week for a short block of time to increase strength. Double bike days are a good way of increasing your kilometres without having to utilise a three-to-four hour block of time. If you are crazy enough to double down and do two sessions in a day, then go for it as the benefits will show in your riding.

Block it up

Talk to your coach if you have one, or if not, plan a bike-specific block into your schedule. The only downside to this is that you might have to drop a few swim and run sessions. This is fine as long as they don’t drop off completely as the fitness will still be there from the increased bike mileage. This type of block should be done in the offseason for a few months. Don’t go overboard as a small increase in training of a particular discipline will have other effects on the other two disciplines – so plan it well and do it smart.

Use a power meter

This relatively new tool is great for monitoring power in training and providing a realistic target to attain and race to in a long-distance competition. It can be used in training for gradual goal setting and to set targets that are attainable and realistic for the athlete. By setting incremental power targets over a longer period of time, you should be able to hit an increased and ‘visible’ goal.

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How to Improve Your Running Drills

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Want to improve your run drills? The real benefits of drills are a result of how they are applied to training, writes Graeme Turner.

Coaches love drills. The Internet, magazines and books are all full of drills and every coach has their favourites. Drills are an important way for people who are learning how to run properly to develop the correct skills to run efficiently and avoid injury. As a coach, I use drills as part of the warm-up for my track sessions. I’ll share two of my favourites later.

Practising a skill develops the muscle memory to execute the technique. In the case of football, repeatedly passing the ball develops the correct technique to accurately deliver the ball to a teammate. In the case of running, drills develop correct run technique; for example, lifting the knee rather than pushing through the calves.

However, what football coaches ascertained is that a player doesn’t just stand there and pass the ball. They may be doing that while running at full speed. And they may be passing the ball running at full speed with a 100-kilogram opponent running at them at full speed.

3 stages of acquiring a skill

  1. Learn the core skill.
  2. Learn the core skill at speed.
  3. Learn the core skill at speed under game (or race) conditions.

You may notice now that if you watch a football practice session the drills are performed not standing in a line but with trainers running at them with padding trying to knock them over.

Most football players at the top level typically already have the core skill – they need to hone that skill under the intense pace and pressure of top-grade football. This is something that has changed over the last decade as coaches have learnt the criticality of developing skills under game pressure; however, in many ways running is still at stage 1 – Learn the core skill.

Incorporate the drill into a run

Running drills are typically practised during a session and then the run component of the session is executed. The assumption is that the skill will develop the muscle memory and this will then, via some form of osmosis, translate into actual running. However, the drills, like the old football sessions, are performed statically (in place) and not under pressure. Over time this skill may translate to the athlete’s run but, at best, this will take a great deal of time.

By adopting a football-style approach, the outcome of the drill can be reached more quickly and the skill becomes more resilient to the pressures of a race. Rather than practising a drill and then running, try incorporating the drill into a run.

Here’s what I do during running sessions

Run 100 metres starting at an easy pace. Once you reach the 50-metre mark, build up pace so that by the end of the run you are at about 85 percent of full pace. Note, for sprinters, the end pace may be closer to 100 per cent.

Now, do the same build but at the 50-metre mark start focusing on a key skill. For example, focus on lifting the knee rather than pushing off the ground. Keep this focus while building up the pace to the end of the interval. Performed statically, this is the traditional ‘marching drill’; however, we are focusing on the skill while running and progressively adding more pressure (pace).

Don’t expect to ‘get’ this straight away. It may take a few run-throughs to develop the skill. I actually do this when racing – focus on a drill for a while in a run as a way of not only ensuring good technique but also as a means of distraction.

Many other drills, such as ‘tunnels’ (keeping the head level), can also be practised this way, even the traditional ‘butt kick’ drill – probably the most commonly incorrectly performed drill – can be performed this way. Curiously, performing butt kicks while running typically means the runner performs this drill correctly with their knee pointed forward rather than straight down.

Two of my favourite drills

Hot Tin Roof

Ground contact represents deceleration. The greater the ground contact time, the greater the loss of momentum and energy. Picture the running track as a hot tin roof. As your foot is about to hit the hot tin roof, focus on pulling the foot up so that it spends the minimum amount of time being ‘burnt’.

Ninjas

A common mistake runners (and coaches) make is focusing on the drill and not the outcome. Butt kicks are a great example of how focusing on the drill itself can create the wrong outcome. ‘Ninjas’ is an example of a drill where the focus is on the outcome, which ultimately is what every runner seeks. At the 50-metre point, focus on running silently – like a ninja trying to sneak up on somebody. This is a great drill to do with a partner as you can compete to see who can make the least noise. Like the hot tin roof drill, this facilitates a much shorter and lighter ground contact time and also tends to mean the runner becomes less flat footed. I could call this running quietly, but ninjas sounds much cooler.

Rather than make drills a separate part of your session, incorporate them into the run itself. Not only will you learn the skill faster but the skill becomes less likely to break down under race conditions.

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Strength Training for Age-Group Triathletes

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Strength is important for endurance athletes and takes time to generate, but there are a few tricks, that will help you maximise your training time.

I drive my coach crazy asking to train more, but I am slowly learning that training smarter is better than training harder. There are many days when the body just isn’t up to the task of training, and sitting at your local cafe will be of more benefit than flogging a dead horse, so to speak.

For the majority of age-group triathletes who have full-time jobs and a family, it is important to make the most of any training time. While it is important to do long, slow sessions to build endurance, there are a few tricks of the trade’ that I have picked up over the years to build strength endurance without having to swim endless laps of the pool, ride for hundreds of kilometres and run for hours on end. Here are a few for your consideration.

Swim

Swimming strength is important, as, come race day, it will allow you to combat choppy seas and the whitewater of a mass swim start. A big part of my swimming involves using a band to hold my ankles together with a pull buoy and hand paddles to build strength. Doing a one-kilometre swim of 10 times 100-metre efforts with just five seconds rest will give you the same strength workout as swimming 1.5 kilometres.

Bike

Long rides are great to build up strength and muscular endurance; however, for those wanting to improve, big-gear hill repeats can also replicate the aforementioned training effects. Triathletes have been using this type of session for years, as doing seated climbing in a big gear (usually 60-to-70 cadence) helps to build leg strength, which usually only comes from long hours out riding.

Run

A great way to get more out of your run is to add interval repeats. These are great to do on the treadmill and help to improve your speed and leg turnover. A simple speed session of 10 times one-minute on and 30 seconds off at just over race pace speed will help you to run faster come race day.

Recovery

The biggest part of endurance sports training is doing the right recovery. Your ability to recover plays a big role in injury prevention and how well you can back up for your next session. Stretching, sleeping and hydration are the key points to focus on. If you are feeling particularly tired, then often a simple stretch session will be much more beneficial for you than a training session on an already tired and fatigued body. Often the hardest thing for any triathlete is knowing that you might just need a day or two off in order to help the body recover and refocus.

The important message is that more is not always better. If you can learn to train smarter and make the most out of every session, then you will see big gains. After all, everyone can do the work but it is those who train smarter who see the biggest improvement.

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How to Tackle Hills on a Triathlon Bike (TT)

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For many newbie triathletes, climbing can represent one of the greatest challenges when it comes to riding. Once that road in front of you starts to rise, it can be a struggle to maintain rhythm and remain comfortable. Apart from clocking up serious hours riding on mountainous roads (which of course is great for building bike strength), I’ve put together a few pointers that should make you faster and more efficient when riding up hills. When climbing, it is important to be smart about the amount of energy you expend and to choose the best position on the bike relative to your terrain.

There are three climbing positions that you can adopt on the bike. Each position comes with its own pros and cons, so it is important to understand when to adopt which position and why.

Aero bars

If it’s a short climb or it has a shallow incline, it’ll likely pay to stay on the aero bars for as long as possible. While racing, a general rule is that the more time you can stay in the aero position, the faster you will be over the duration of the ride.

Managing exertion

Keeping your power output on the bike as stable as possible is usually the best way to approach the bike leg. Big spikes in power, caused when climbing or pedalling out of tight corners, is the easiest way to increase leg fatigue. When climbing during races, you should only increase your power output by at most 10 percent compared to riding on the flat. Using a power meter on your bike is by far the best way to monitor how much power you’re putting out during any stage of a race. It’ll help you keep your effort at a steady rate. Alternately, a heart rate monitor is another great tool that’ll help you keep your effort as even as possible – particularly when climbing.

Seated climbing

As the road starts to get steeper, the aero benefits of remaining in an aero position become negligible. It’s time to sit up and put the power down. Climbing while seated should be adopted when the climb you face is such that you feel you need to break from the aero position – but not so steep that you feel you need to get out of the saddle. Staying seated while climbing will also help keep your heart rate lower than when standing. This means you’ll be using less energy.

Cadence

For most triathletes, a cadence of between 80-to-95 RPM is ideal for racing. Once you hit a climb, try to keep your cadence roughly the same as you employ on the flat. Cadence is similar to power output in that you should aim to keep it as consistent as possible. If you are standing to climb and are pushing hard with a low cadence, the level of muscular fatigue will increase. Alternately, climbing while out of the saddle with a cadence of 110 RPM or more will see your heart rate skyrocket.

Gearing

When I am setting up my bike for a major race, I always take a good look at the course profile a few weeks out from the event. I make sure my bike is rocking a rear cassette that I know will give me a good range of gearing options for that particular course profile. For example, if it’s a hilly course that’ll require a lot of climbing, I fit a rear cluster of 11/25 to ensure that I have the gears I need to maintain a good cadence through the climbs.

Standing – out of the saddle

When racing, it’s important to remain as aerodynamic as possible. However, on steeper climbs you will find that you are not able to generate the power needed down on the aero bars. Standing up on the pedals will give you more power as you’re using your body weight to put power into the cranks. This comes at a cost, though. Standing while you pedal will lead to increased heart rate as you’re employing more of your upper body to generate power. Climbing out of the saddle should be saved for mountain goat terrain.

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Polarised to Pyramidal Training Intensity Distribution: The Principle of Specificity is Key

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A new blog post has been a long time coming (we’ve been busy!; me doing some training, work and the addition of a little girl and Prof writing a book), and with Ironman NZ behind us for another year, it’s given me the chance to write something I’ve been wanting to express for some time.

I love a bit of social media interaction. Whilst I’m not the most vocal, I do enjoy keeping an eye on the latest hot topics in the world of endurance sports and Ironman Triathlon. Over the past few months or so, “polarized training” has become a real buzz word in the triathlon training world. Particularly Ironman. But is this really the best way to train when considering an event like Ironman? Here is a spin on it from Plews and Prof.

Training intensity distribution and polarised training

When we refer to training intensity distribution (TID), we are talking about how much of the time we spend in low, moderate and high training intensity zones.

Figure 1: Training zone demarcation using the classic three zone model.

Figure 1 shows a great illustration of the zones we’re talking about from the father on the topic for us, Professor Stephen Seiler, which I’ll use throughout this essay. Have a read of his 2009 paper if you want to really geek out. In a nutshell, there are generally two main models of TID that have dominated the literature. These are namely the polarised (1) and the threshold (2) models of training.  The polarised model was first described within the training performed by the East German system from 1970-80, whereby a high volume of low-intensity training appeared balanced against regular application of high-intensity training bouts (~90% to >100% VO2max). This was partially confirmed in 2004 by Fiskerstrand & Seiler (1), who showed a “polarized” pattern of training also when they explained the training and performance characteristics of 28 international Norwegian rowers developing across the years 1970-2001. This polarised model is said to be described as performing about 75-80% of your training at a low intensity (<2 mM blood lactate), 5% at threshold intensity (~4 mM blood lactate), and 15-20% at high intensity  (>4 mM blood lactate) (3). This training organization contrasts the classic threshold model (~57% low intensity, 43% threshold, 0% high-intensity (4)) of endurance training, whereby large volumes of mid-zone threshold work is thought to be optimal (2). This former study on world class international rowers provided evidence to support the importance of the polarized training model for endurance athletes striving to be the best in the world, and subsequently has been largely adopted by athletes across many endurance sports. (5,6)

Iron distances races: Racing in the black hole

What’s very interesting about the polarized training method as it relates to Ironman, is that most of the research has been carried out in sports where race pace intensity is above the second (“anaerobic”) threshold. Sports like rowing 7 for example, (where much of the TID research has been done), is closer to VO2max intensity. To illustrate, Figure 2 shows an example of the typical intensity breakdown over a 2 km rowing race (split into the three-zone model), where the majority of time spent during the 6-8 min race is above the heart rate associated with the anaerobic threshold. Even in a cycling road race there would be substantial amounts of time spent in the low intensity bandwidth (below the first aerobic threshold, whilst sat in the peloton), alongside shorter times spent above the second threshold (closing gaps, making breaks etc.).

Figure 2: The typical heart rate intensity distribution of a 2 km rowing race. 24% at low intensity (it takes time for HR to rise), 34% at a moderate intensity (still rising) and 42% at a high intensity.

Comparatively, the intensity distribution of Ironman racing is vastly different, with most of the time being spent in the moderate intensity bandwidth. Figure 3 shows my HR distribution during the Taupo 70.3 event in December 2017. From this, its clear that most of the ~4h race duration is spent at a moderate exercise intensity. To take this a step further, we can look at my race for Ironman New Zealand 2017, where there is even more time spent in the moderate intensity heart rate bandwidth (Figure 4).

Figure 3: Time in Zone 70.3 Taupo bike (top: 2 hr 14 min) and run (bottom: 1 hr 18 min). Bike includes 2% low intensity, 72% moderate intensity and 26% high intensity. Comparatively, running includes 0% at low intensity, 54% at moderate intensity and 46% at high intensity.

When looking at Figures 3 and 4, keep in mind that the moderate intensity training bandwidth is quite large (145-160 b.min-1 cycling and 150-165 b.min-1 running). The Ironman distance mostly happens in the low end of this bracket (average and max HR for bike and run respectively = 145/157 and 151/163 b.min-1) while the 70.3 distance occurs near the top (154/161 and 164/176 b.min-1)

Figure 4: Time in Zone for full ironman (2017 Ironman NZ) bike (top: 4 hr 58 min) and run (bottom: 2 hr 55 min). Bike includes 25% at low intensity, 74% at moderate intensity and 0.2% at high intensity. Comparatively, running includes 4% at low intensity and 96% at moderate intensity and 0% at high intensity.

Pyramidal Model of Training Intensity Distribution

More recently, a number of retrospective studies have put forth another model of TID for cycling, (8) running, (9) and triathlon, (10) termed the “pyramidal” model. Here, most training is still carried out at low intensity, however there are decreasing proportions of threshold and high-intensity training performed. This is a model less discussed that many might not be familiar with. Indeed, we often assume that an athlete who is not polarized in their TID must be in the “threshold” model by default. However, published research has revealed this middle-ground model that we need to appreciate.

Exact defining percentage breakdowns of the Pyramidal model have yet to be clearly established, however this general implies ~25-30% and 5-10% of TID at moderate and high intensity training levels, respectively, with the balance being low intensity training (50-70%). (3) As such, within the pyramidal model of TID, we expect to see less training time at a low and high training intensity, and more time at moderate training intensity. From a specificity standpoint, this middle ground training is much closer to the demands of ironman racing (Figures 3 and 4). Thus, when race day approaches, and training sessions become more “specific” and closer to race intensity, it stands to reason that perhaps the Pyramidal model may particularly suit long course triathletes.

Figure 5: 1 week of training (7 January until 13 January). 64% <LT1, 25% LT1-LT2 and 11% >LT2

Figure 5, shows my TID during one week in the month of January 2018 (competition phase) before the New Zealand National Middle-Distance Champs. As we can see, my TID certainly fell in line with the Pyramidal model.

Take home points

For Ironman distance racing, or any sport preparation for that matter, we have to consider the principle of specificity. For Ironman, as we are still working in an aerobic event, building aerobic endurance is of key importance. Thus, however you’re skinning it in your Ironman training, a fundamental principle needs to be an aerobic foundation. Ideally, we should be working within a range of TID, that span across the polarized (80/20) and pyramidal (60/40) models, depending on the phase of the training cycle. For example, early season training might look more polarized, while pyramidal may appear to form, as we get closer to racing.

One final point, it that we must also acknowledge the role of athlete health (11) and the stress that training places on the autonomic nervous system (12,13) when substantial amounts of training time are performed above VT1. Thus, future research may want to consider describing the optimal durations of pyramidal and polarized training phases in the diets of Ironman athletes.

 

References

1.    Fiskerstrand A, Seiler KS. Training and performance characteristics among Norwegian international rowers 1970-2001. Scand J Med Sci Sports 2004;14:303-10.
2.    Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform 2010;5:276-91.
3.    Stoggl TL, Sperlich B. The training intensity distribution among well-trained and elite endurance athletes. Front Physiol 2015;6:295.
4.    Neal CM, Hunter AM, Brennan L, et al. Six weeks of a polarized training-intensity distribution leads to greater physiological and performance adaptations than a threshold model in trained cyclists. J Appl Physiol (1985) 2013;114:461-71.
5.    Laursen PB. Training for intense exercise performance: high-intensity or high-volume training? Scand J Med Sci Sports 2010;20 1-10.
6.    Seiler KS, Kjerland GO. Quantifying training intensity distribution in elite endurance athletes: is there evidence for an “optimal” distribution? Scand J Med Sci Sports 2006;16:49-56.
7.    Plews D, Laursen PB. Training intensity distribution over a four-year cycle in Olympic champion rowers: different roads lead to Rio. International Journal of Sports Physiology and Performance 2017;In Press.
8.    Lucia A, Hoyos J, Pardo J, Chicharro JL. Metabolic and neuromuscular adaptations to endurance training in professional cyclists: a longitudinal study. Jpn J Physiol 2000;50:381-8.
9.    Esteve-Lanao J, San Juan AF, Earnest CP, Foster C, Lucia A. How do endurance runners actually train? Relationship with competition performance. Med Sci Sports Exerc 2005;37:496-504.
10.    Neal CM, Hunter AM, Galloway SD. A 6-month analysis of training-intensity distribution and physiological adaptation in Ironman triathletes. J Sports Sci 2011;29:1515-23.
11.    Maffetone PB, Laursen PB. Athletes: Fit but Unhealthy? Sports Med Open 2015;2:24.
12.    Plews DJ, Laursen PB, Kilding AE, Buchheit M. Heart-rate variability and training-intensity distribution in elite rowers. Int J Sports Physiol Perform 2014;9:1026-32.
13.    Seiler S, Haugen O, Kuffel E. Autonomic recovery after exercise in trained athletes: intensity and duration effects. Med Sci Sports Exerc 2007;39:1366-73

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Runners’ Toenail Problems: Do Triathletes Even Need Nails?

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Quick summary: If you’ve spent a lot of time training for triathlons, you may have experienced problems like black, thickened, or ingrown toenails. You may have lost toenails now and then as well. These issues affect the big toe most of all. Some runners and triathletes avoid these problems by having them surgically removed. Is that a smart idea? Do you really need your toenails?

Causes of toenail problems for triathletes

  • Ingrown toenails are caused by repeated stress that drives the toenail into the soft flesh of the toe, combined with growth of either the toenail or the skin of the toe. This can cause a lot of pain and a few visits to the doctor.
  • Black toenails are caused by repeated contact between the toenail and the shoe. This causes bleeding, and it may turn the toenail black. The blood can cause the toenail to separate from the toe, opening you up to bacterial and fungal infections before another toenail grows in its place.
  • Permanent toenail thickening occurs when damage to the root, or “matrix”, of the nail causes it to become deformed. The nail will grow according to the new shape of the root. It will often grow thicker and look grey or yellow, like a fungal infection. This condition is permanent and can harm your triathlon performance.

What happens if you have your toenails surgically removed?

The flesh underneath your toenails is very sensitive. However, if you have your toenails removed, the flesh normally grows thicker, tougher, and far less sensitive. If you have cosmetic concerns, you can add nail polish to this area. People won’t be able to tell the difference unless they’re near you. The doctor will use either a laser or a chemical, and the procedure is painless.

On the other hand, there are some people whose toes won’t create that protective layer of skin. You could be one of them. The only way to find out is to have your nails removed.

The verdict: Whether you have toenails or not won’t affect your running ability. An ingrown toenail will until you have it treated. A permanently thickened nail will also affect your speed and endurance, and that’s not treatable.

Your two options are prevention and surgery. As a triathlete, you’re going to have cosmetic issues. That’s just a fact. If you’re not into the idea of surgical removal, there are some steps you can take to minimize damage to your toenails.

  • Wear the correct size shoes. A shoe that fits well will prevent all the microtrauma that can cause bleeding under the nails.
  • Keep the nails well trimmed. If they’re even a little bit too long, they can cause shoe-related trauma on the inclines and declines.
  • Use skin lubricant. This will prevent a lot of soreness, bruising, and other problems caused by accumulated trauma. This is a method Dr Christopher Seglar, a San Francisco sports medicine podiatrist and triathlete, uses on long runs of 30 kilometres or more. His toes are fine on shorter runs. However, if you train a lot, you may want to use skin lubricant for those, too.

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