Monday, 19 December 2011

A Holiday Treat (From: Science)

Well my friends, its that time of year again!  Regardless of what holiday you celebrate, I think it is safe to say that most of our diets take a little bit of a dive in the month of December.

Take me for instance; yesterday I ate cookies and milk for breakfast followed by leftover chips and cheeses for lunch.  Then, logically enough, I consumed chips, cheese and cookies for dinner while watching this movie.  A classic film for a classic holiday season diet.

All of these treats reminded me of something my mom always used to tell me growing up (and still does to this day), "chocolate is good for you."  Yes, when I felt completely full and unable to ingest more Christmas chocolate, my mom would cheer me on with encouraging phrases such as, "eat it, it's good for you," or "it's cocoa, eat it."  So I would.  

Was she right all along?  I decided I had to go to the literature and find out.


In my search I came across this study published in 2008 in the American Journal of Clinical Nutrition.  Luckily for all of you, this one is available in full text for free online-it's a Christmas miracle!  Enjoy this nice holiday read as a gift from me to you!

One of the historically accepted benefits of chocolate involves its impact on the cardiovascular system.  Specifically, the active ingredient within cocoa (flavanoids) are thought to improve endothelial function.  What is endothelial function?  Well, the endothelium is the internal layer of your blood vessels.  If it is functioning well, you will be less likely to have high blood pressure, and less likely to experiencing blood clotting.

So, by having an impact on your endothetlial function, the flavanoids in cocoa could potentially decrease your blood pressure and the odds of developing a clot - that is what this study looked at.

How it was done:

In the study, there were two phases. During each phase, subjects were randomly assigned to consume either:

  • 74g chocolate containing 22g of cocoa
  • 74g placebo chocolate containing 0g cocoa
  • 22g of sugar free cocoa
  • 22g of sugared cocoa
  • placebo (no cocoa)
Then, the researchers measured parameters including blood pressure (BP) and flow-mediated dilation (FMD).  FMD is essentially a measure of the diameter of the blood vessel and therefore one way of measuring endothelial function.

What they found:

Here are the main conclusions the researchers reached: 

  1.  FMD and BP improved after eating chocolate compared to the placebo group in Phase 1.
  2.  FMD improved after eating both the sugared and sugarless cocoa compared to the placebo group in Phase 2.
  3. BP improved after eating the sugarless cocoa compared to the placebo group in Phase 2.
What does this mean?

My mom was right.  Again.

But really, I thought this study was fascinating.  With ingestion of chocolate containing cocoa, or pure cocoa itself, the subjects consistently showed better endothelial function.  The researchers attributed these changes to the cocoa flavanoids rising in concentration within the blood.  This study also shows that while both sugared and sugar free cocoa can have a positive impact on endothelial function, the sugar free option has an even more significant impact.

Nevertheless, there are a few things you should keep in mind when analyzing these results.  First of all, these changes were measured only once, not over a period of time.  So, even though these benefits were seen at the initial point of measurement, that does not mean they will persist days or even hours later.  Secondly, it is also important to keep in mind that these measurements were taken after eating cocoa once.  Perhaps the vascular response would not have been as profound if the individuals consumed cocoa on a regular basis.   

Either way, this study does show that a one time episode of cocoa ingestion will have an acute, positive impact on endothelial function.  Based on that, you can enjoy your dark chocolate a little more guilt free!

Happy Holidays!

Thursday, 1 December 2011

Elliptical VS Treadmill

As some of you may know, I decided to run a marathon at the beginning of November on very little training.  In fact, my longest run prior was about 18 km, while the marathon itself is 42.2 km.  So, I almost did half of the distance beforehand- that's good enough, right?  WRONG!

Not the smartest training strategy, and definitely not what I would recommend.  Nevertheless, I had a lot of fun, and the race was actually not that painful.  If you ever want to try a really fun and fast marathon (or half), give the Road2Hope Hamilton Marathon a shot!

So, while the race itself did not rank overly high on the pain scale, I soon after realized that my lack of training would come back to haunt me.  The recovery has been slow- including abnormal walking of 7-10 days duration, which has been followed by a few random, slow, awkward, painful runs.  Note to self- "do long runs in training prior to marathon."  If  only it were as simple as this guy made it seem.

In desperation to get some exercise in, I have resorted to something I never thought I would: the elliptical machine.  Laugh if you want, the machine is actually great; it gets my heart rate up, and my legs feel amazing as I do it (amazing= not quite as injured).  I just hope I don't turn into this guy.


Naturally, I started to wonder how effective the elliptical is as a replacement for running.  In my search of the literature, I came across this study published in the Journal of Strength and Conditioning Research.

In the study, 18 subjects aged 19-24 were put through a series of tests on both the treadmill and elliptical machines.  The study measured the following parameters: oxygen consumption, energy expenditure and heart rate at a set level of perceived exertion.

What they found:

This is what they researches found when comparing the elliptical and treadmill trials:

1) No difference in VO2 max (measure of maximum oxygen consumption)

2) No difference in TOTAL oxygen consumption

3) No difference in energy expenditure (measured in kcal)

4) Interestingly, the elliptical trials resulted in a higher average heart rate then the treadmill trials in both females and males.

So, in other words, these people were sucking up just much oxygen and burning just as many calories regardless of which machine they were on.

So what does all this mean?

Overall, as you can see based on these results, the elliptical is undoubtedly a great way to cross train for running, at least from a cardiovascular standpoint.  The most interesting component to these results, however, is that at a set level of perceived exertion, the subjects were able to push themselves harder on the elliptical resulting in a higher heart rate.

Why would this be?  Well one idea stems from the subjects themselves.  The population was noted as being healthy, but also not committed to any regular exercise program.  So one possibility is that the elliptical's non-impact and fluid motion allowed the people to push themselves harder at the same level of perceived effort when compared to the jarring and uncomfortable nature of running.  I think it would be really interesting to repeat this same study with trained runners to see if they would get more out of the treadmill workout compared to the elliptical (if I had to guess, I would say they would). 

Another obvious possibility mentioned by the authors is that the elliptical does include arm movements that are more exaggerated then that of the average runner. This could also account for the increased metabolic demand without increasing the perceived level of effort. 


So is the elliptical a good way to compliment running training?  Absolutely.  This is especially true for people (like myself) who are injured, and want to maintain some fitness while they recover.  On a scale of  "doing nothing" all the way to "running," these results show that the elliptical is much closer to the "running" end of the spectrum.

BUT, can the elliptical machine replace the treadmill as a means to train for running?  No.  If you want to get better at running, the obvious thing to do is run.  The elliptical undoubtedly will help from a cardiovascular standpoint, but from a biomechanical and muscular standpoint, running is best.  I suspect that if you train hard on the elliptical, you will potentially turn into a decent runner...but surely an amazing elliptical-er (such as Tony Little).

Wednesday, 23 November 2011

Sprint Interval Training vs. Endurance Training

As some of you reading this article may know, I lead an interval running group out of Runners' Choice Waterloo.  All I keep telling this great group is that intervals are the most efficient use of your time- if you want to get fit and fast this is the most efficient way to go!! 

Then I started thinking to myself, "hmm, maybe I better check this out just to make sure I am 100% right."

In my search of the recent literature, I came across an article published in January 2011 out of the Journal of Medicine & Science in Sports & Exercise

This article proved exactly what I expected: sprint intervals (the awesome and fun workouts my group does), with a much lower time commitment, induced identical performance and physiological improvements compared to longer bouts of endurance training (long boring runs that regular people do not always have time for).

Study Design:

This is a breakdown of how the study was completed.  20 healthy subjects were divided into 2 groups.  Both groups would undergo 3 training sessions per week for 6 consecutive weeks.  This is what each group did:
  • Group 1: Endurance Training:
    • 30 minute runs (for first 2 weeks), 45 minute runs (weeks 3 and 4), and 60 minute runs (weeks 5 and 6).  All runs were done at 65% of their maximal effort.
  • Group 2: Sprint Interval Group:
    • 30 second maximal effort bouts with 4 minutes active recovery.  They would complete 4 sets in weeks 1 and 2 and up to 6 sets in weeks 5 and 6.
As you can see based on these numbers, the endurance group was working 30-60 minutes per session.  By contrast, the sprint interval group was only working a total of 18-27minutes (where most of that time was spent recovering). 


The improvements seen in both groups were measured in a number of ways (ranging from body fat percentage to 2000m Time Trial time).  Despite the sprint interval group spending less than half the amount of time running compared to the endurance group by the final weeks of the program, they still showed equivalent levels of improvement:

  • 2000m Time Trial: 
    • Both the endurance group and the sprint group showed about a 30s improvement throughout the 6 week program.  I was especially excited about this parameter because a ~2km TT is how we measure progress in the Runners' Choice group!
  • VO2 max:
    • This is the measure of the maximum amount of oxygen your body can consume per unit of time per kg of body weight.  Again, both groups showed similar levels of improvement (about 12% with each).
  •  Body Composition:
    • This one is interesting!  Both groups gained about 1.0% lean mass (muscle), which again is a positive sign for both groups.  However, the interval group lost 12.4% body fat, while the endurance group lost only 5.8% body fat.  While there is no significant difference in this study, these results are consistent with other studies on interval training.  Bottom line: you lose more fat in less time with intervals!
  • Cardiac Output:
    • This is the measure of how much blood your heart can pump throughout your body.  Interestingly, the endurance group showed a 9.5% increase, while the interval group showed none.  This shows that while interval training is extremely useful, it cannot 100% replace all forms of training. 
Bottom Line:

As you can see, interval training is an absolutely crucial component of training.  In approximately half of the total training time you can achieve:

  • The same improvements in your race times
  • The same improvements in your VO2 max
  • The same increases in lean body mass
  • Higher levels of fat loss
The only downside is that intervals are hard and painful!  So make sure you join a group or get together with some friends who can push you- otherwise your 100% maximal effort will quickly turn into 70% or less (or at least mine would).

A Few Additional Thoughts (after the fact):

Also, keep in mind that while you cannot replace long runs with intervals, by the same token you cannot eliminate the need for intervals with long runs.  Other parameters such as how your body produces and manages lactic acid were not measured in this study- something that interval training will have a more significant impact on compared to endurance runs.  

At the end of the day, best case scenario, doing both is ideal.  However, if you are limited by time, go with the interval workout.

Click here for the article

Monday, 31 October 2011

The Pose Method of Running

Here it is, just as promised, the Pose method of running.  Originally I was planning on outlining exactly what it entails in words, but then I started confusing even myself (and I already KNOW what it's all about).  So, I figured the best way to learn about this method of running is to watch it:

Go to about 1:25 into the video to get straight into the explanation of what this style of running entails.

The Basics:

So, as you can see from the video, this running style incorporates a few changes to the "traditional" way us North Americans typically run.  Rather than driving our thighs forward and extending our feet in front of our torso, the Pose method involves striking the ground with the foot directly beneath the hips.  Instead of propelling ourselves forward using our quads and gluts, the Pose method suggests we simply snap our feet backwards by activating the hamstrings.

Why Does it Work?:

The researchers suggest this style of running is more efficient for two major reasons.

(1) You are not fighting gravity by trying to propel yourself into the air.  Rather, you are leaning forward and using gravity, as this is more of a method of "controlled falling."  Your legs are simply landing underneath you before you actually fall. 

(2) By keeping the foot directly underneath the torso at point of impact, this prevents the subtle deceleration that is induced when the foot is extended directly in front of the body at the point of impact (with a heel strike).  See this video to visualize exactly what I am talking about.

Does it Actually Work?:

Well, the logic seems there, but I have not been able to identify any high quality independent studies proving that this is the MOST efficient way to endurance run.  Does anybody else know of any?

If you're curious if it will work, give it a shot, and see what happens.  Just make sure you give your body sufficient time to adapt to the new style (i.e. don't start out by running 20km with the technique, get injured, and then quit).  Start by mixing in 1km of Pose running into your weekly long runs, and progress by 1-2km per week for the first 2 months. 

The Undervalued Strength of Pose Running:

Aside from potentially being more efficient, there is another reason you may want to consider using the Pose method.  In this relatively recent study, the biomechanics of Pose running in relation to two longer strides was investigated.  The study found that:

 "Pose running was associated with shorter stride lengths, smaller vertical oscillations of the sacrum and left heel markers, a neutral ankle joint at initial contact, and lower eccentric work and power absorption at the knee than occurred in either midfoot or heel-toe runninng."

So, in other words, the pose method puts less stress on your hips and knees.  So, if you find you are suffering from recurring hip or knee injuries, then shortenning up your stride and giving the Pose method a try is definitely worthwhile.

By contrast, because of the shorter stride and forefoot strike associated with the Pose method, there is a resulting increased stress put on the Achilles tendon and soleus (calve) muscle.  Therefore, the Pose method may save the knees and hips at the expense of these structures lower down on the leg.  So, if you are suffering from injuries in the calve or Achilles tendon, lengthening out your stride and staying away from the Pose may be worth a shot.


The Pose method of running involves a shorter stride and a forefoot strike which occurs directly underneath the runner's hips.  This results in more of a controlled fall rather than propelling yourself forward.  It might be more efficient than conventional North American running, and more importantly, will help to dissipate some of the stress going through your knees and hips.

Reduced eccentric loading of the knee with the pose running method.

Wednesday, 5 October 2011

Your Brain on Excercise

Welcome back to yet another enthralling addition to my blog!  We all know that exercise is good for the body.  However, recent research has shown that  exercise is good for the brain too (surprise, surprise).  But, maybe not in the way you're thinking.  I am not talking about that temporary and somewhat fleeting runner's high you get after a tough workout.  Instead, I am referring to recent research which has proven exercise to have a much more profound impact on the brain- an effect that results in long lasting and extremely positive changes in brain function. This is exactly what we will be exploring with today's article.

Just to forewarn you, we will have a little change of pace with this post as I was fortunate enough to interview Jeremy Walsh on the subject matter.  I say fortunate for two reasons: (1) Jeremy is conducting novel research in the field, and thus has a great understanding of the topic and (2) it saves me from having to read up prior to writing an article.  Maybe I should do more interviews!

In any case, here is a brief background on Jeremy before we get into the interview:

Jeremy Walsh
  • Completed a Hon. BA in Kinesiology at WLU (Psychology minor)
  • Thesis: "The Influences of pulsed magnetic fields on indices of muscle damage and repair"
  • Currently studying in the Human Vascular Control Lab at Queen's University
  • Ontario Graduate Scholarship recipient 
Question #1: Thanks for taking the time to do this Jeremy.  So you are currently studying the connection between brain physiology and exercise.  How, exactly, has exercise been shown to influence our brains?

"In a nutshell, as we age, our brains deteriorate in a predictable fashion.  The size of our brains shrink, there is a decrease in blood flow to the brain, and functions such as memory and processing speed decline.  Fortunately,  exercise has the power to positively change blood flow, structure (size) and the function of the adult brain at any age!  This is really exciting stuff because the brain used to be regarded as a rigid structure, unable to change. Only within the last 15 years have people really started paying attention to the fact that the brain is 'plastic' or able to change.
So how does it do this? 

1) Exercise increases brain blood flow. This provides an increase in the delivery of oxygen and nutrients which are vital for maintaining healthy brain cells.  With prolonged, regular exercise, new blood vessels are formed in the brain which elevates brain blood flow... even at rest; this provides a perfect environment for cells to thrive and grow. 

2) Exercise increases the release of important hormones and growth factors.  Specifically, exercise increases Insulin-like growth factor-1 (IGF-1), brain derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF).  These growth factors work together to improve learning and memory, increase the connections between neurons (faster processing = faster thinking), and actually stimulate the growth of new neurons (vital for storing new memory and improving capacity to do work)." 

Question 2: So, what type of practical applications are we looking at here?  Is the impact of exercise significant enough to help the average person maintain their cognitive function longer in life?  Is there the potential to help with neurological disorders such as Alzheimer's? 

"There is definitely a huge potential for this to be applied to both healthy aging (maintenance of cognitive function) as well as preventing the onset of neurological disorders.  Studies have found that exercise training at any stage of neurological disease  progression (ex. early or middle stages of dementia) can slow and in some cases stop, the progression of the disease.

For the average person, participation in regular physical activity extends their cognitive function by years.  Exercise (with regards to brain function) is not like a drug where once you stop taking it, the effects wear off.  Regular exercise has a profound impact on the brain years removed from training.

Practical application is simple and clear - benefits can be garnered by staying active and finding ways to keep moving... the more active you are, the more your brain will benefit."

Question 3:
Has the research shown what type of exercise is best?  Is it long bouts of cardio?  Interval training?  Resistance training?

"The research on exercise type is starting to expand.  For the most part, aerobic training has been at the forefront of this research, mainly because it is easy to measure the amount of work being done and it is easy for an individual to adhere to the training.  Resistance training, however, has also been shown to improve cognitive function and studies show that it has a GREATER impact on the brain than aerobic training.  I would speculate that this is because of the increases in growth hormones and the changes in body composition associated with resistance training.  What I find to be really cool is that aerobic training and resistance training COMBINED has an even GREATER effect on cognitive function than do either training modality alone.

I have not read any studies that directly measured brain function with interval training, however, interval training has a positive effect on the release of growth hormones (IGF-1) and this is directly linked to brain function.  I hypothesize that interval training (provided it's a sufficient stimulus) would have a positive effect on brain function. 

At the end of the day, exercise, regardless of type, will improve brain function.  The take home message remains - stay active, keep moving, and find something that YOU enjoy because motivation and enjoyment are key to positive changes in the brain."

Question 4: How about for the recovery from traumatic brain injuries, such as a concussion?  Or, recovery from a stroke?  Would exercise help?   

"Exercise is quickly being recognized as a key component to recovery from various traumatic brain injuries.  Animal studies have shown that exercise BEFORE a stroke helps protect the brain from potential damage during a stroke.  Exercise AFTER a stroke is key to successful rehabilitation.  It all comes back to the increase in blood flow and growth factors... these events act as 'miracle grow' for the brain. 
Regarding concussions, active (exercise) rehab is an integral part of post-concussion recovery; however, exercise should only begin once the person is free of their symptoms. The response to exercise will be completely based on the individual. Improving brain blood flow and increasing growth factors will aid in the healing of the injured tissue."  

Question #5: So what is your current research geared toward?

"I cannot fully disclose this part as I am still in the process of writing my proposal, however, we will be examining how exercise in combination with a mental task (cognitive training) will work to enhance brain function beyond that of exercise or cognitive training alone."

So, there you have it, yet another reason to exercise!  Thanks to Jeremy for taking the time to answer my questions.  If there is anything you are curious about, feel free to e-mail me and I will direct any questions toward Jeremy.

Next week we will be looking at an (apparently) more efficient way to run: The Pose Method.

Wednesday, 28 September 2011

Part 2: Sweat, Salt and Minerals

What originally sparked interest in creating this 2 part series was the then-upcoming Centurion race in Collingwood.  As you may have noticed, I strategically posted only the 1st part prior to the race.  Shockingly, this strategy did not work as lots of fast guys still destroyed me.  Maybe they have race secrets they should be blogging about!  Nevertheless, a great day on the bike.  Check out Larry Bradley's race report to get a sense of what it was like to participate in the event.

When you ride for almost 5 hours over the course of 172km, fluid and salt balance undoubtedly play a vital role in maintaining performance.  The easiest way to waste valuable training is to refrain from taking in adequate amounts of either.  Last week's blog addressed how to maintain proper fluid balance, while today we will look at the salt.


This is the mineral that is lost the most as we sweat.  As with everything else, there is obviously variation between athletes, but on average we lose about 1500mg per 1L of sweat lost.

So what happens if we lose too much sweat?  Well, the sodium outside of our cells will eventually be at a much lower concentration than the electrolytes inside our cells.  As a result, our body tries to balance things out, allowing water to travel into our cells.  As the cells fill up with too much fluid, early symptoms such as disorientation and shortness of breath can take place leading to more serious complications such as coma and even death.

As a general rule of thumb, you should consume 1g of sodium for every 1L of fluid you consume.

Fortunately, sports drink companies typically have this figured out, and their products meet this criteria.


Contrary to what a lot of information out there shows, potassium is not an absolute requirement during athletic events.  It is easily replenished via the regular consumption of fruits, vegetables or fruit juices. 

While sodium is the main electrolyte located outside of cells, potassium is the main electrolyte within cells.  This is essentially why it is lost to a much lesser degree while sweating.  Potassium debt is a rare occurrence, and it is typically only seen in those who are malnourished or who are suffering from chronic diarrhea or related conditions.

Other Minerals

Just because we are on the topic, I would also like to remind people to keep a close eye on three very important minerals: calcium, magnesium and iron.  While these minerals are not lost in sweat, athletes who undergo strenuous training are much more susceptible to developing deficiencies.  Calcium and magnesium are both imperative for building and maintaining strong bones, while iron is a key component of the oxygen-carrying hemoglobin within our red blood cells.  Low levels of any of these three minerals can therefore result in osteopenia and anemia.

To prevent this from happening, ensure that you are consuming at least 1000mg of calcium per day (depending on your age and gender) with at least 600 IU of vitamin D.  Magnesium is found in an array of foods including nuts, grains and green leafy vegetables.  The recommended daily allowance is about 400mg/day, and a well balanced diet is usually sufficient in achieving this.  Iron balance is a more complicated issue due to the variation seen based on age and gender, but a well balanced diet high in meat or meat substitutes will help ward off its deficiency.  For more details on iron, see the National Institute of Health website.  In general, you should pay attention for symptoms such as chronic fatigue and stress fractures as a mineral deficiency may be at play. 


So, in the end, the only mineral you really need to worry about on race day is sodium.  A healthy, well balanced diet plays an important role in maintaining adequate mineral levels within your body on a more long term basis.  BUT, on race day, remember:

1g of sodium for every 1L of fluid you consume.

Next time we will be switching gears a little bit, and will be looking at the effects of exercise on the brain.  Until then!


1) Frissell, RT, et. al., 1986. Hypoenatremia and ultramarathon running. JAMA. 255: 772-774.

2) National Institute of Health: Office of dietary supplements. Accessed Sept 27th, 2011

3) Nutritional Aspects of Athletic Performance, Dr. James Meschino D.C., M.S., ND, 2008, Pages 20-24

Friday, 16 September 2011

Part 1: Sweat, Salt and Minerals

Hello all!  Well, after a three week hiatus, we are back in action.  Sorry for the delay on this post- I recently started working from two great clinics (Price Health Centre and New Hamburg Wellness) which have taken away from my precious blogging hours.  Apparently, to my surprise, working two jobs takes up more time than not working at all.  

Stuff On Sweat

Today's blog is in light of the fact that I, along with a number of fellow riders, are going to attempt to do a 160+ km bike race this Sunday in Collingwood.  This race will surely be a great deal of fun, in a "I can't wait until it's over" kind of way.  However, one thing that many of my fellow riders have been discussing is how to handle their fluid and salt balance during a 5+ hour event such as this.  So, today's blog will be a summary of the basics behind keeping yourself hydrated, while Part 2 will discuss how to maintain your salt balance.  

How Much?

It has been shown that on average, athletes sweat at a rate of 1-2L/hour.  There is obviously a huge variability here, and it has actually been shown that in some more extreme cases, an athlete can lose 4L of sweat per hour.  Nevertheless, a general rule of thumb to follow, as recommended by the American College of Sports Medicine is:

Athletes participating in events lasting more than 40 minutes should consume 5-8 ounces of fluid for ever 15 minutes.  

Google tells me that is about 150-240 mL for every 1/4 hour you are competing. This protocol seems pretty basic, and easy to follow.  However, during a race or any other type of athletic event, it is easy to get caught up in the moment and forget to ingest adequate fluids.

Dehydration happens all the time, even to pros.  Sure, you will always drink some liquid- but maybe your 15 minute drinking intervals turn into a 20 minute intervals.  Now, you are consuming 15 ounces per hour instead of 20 ounces.  This may seem insignificant at the time, but it is quite the opposite.

How Important IS Water?

Water plays a number of roles in the body.  During exercise, one of the key functions that it is used for is heat dissipation via evapostranspiration (which is essentially me trying to sound smart- but heat is carried via water from within muscles and other deep tissues to the skin's surface, where it can evaporate). In fact, this process of sweating is one of the reasons why our ancestors made such  great hunters, which you can read about in my article on persistence hunting.  However, as we lose water while we sweat, we also lose are ability to cool off, and eventually our ability to perform:
  • With a 2% loss in water, we start to lose the ability to regulate our body temperature (but performance is ok)
  • With a 3-4% loss in water, some studies have shown up to 30% impairment of muscle performance
  • With a 6+% loss in body water, heat stroke starts to occur (body temperature going over 42 degrees, internal organs starting to "cook," overall not a healthy thing)
Two More Tips

While any water is better than no water, it has been shown that there are a few tricks to enhance how quickly water is absorbed into your system.
  • Research shows that cold water is absorbed more efficiently than water at room temperature.
  • Your sports drinks should NEVER contain more than 8% sugars.  If higher than 8%, there is a significant decrease in how quickly water is absorbed from your intestines into your blood stream.

So, that is all for Part 1 on maintaining your salt and water balance.  Overall, it is a fairly straight forward topic, but also very important for obvious reasons.  The key things to keep in mind include:
  • Drink 5-8 ounces of fluid every 15minutes                                                                                           
  • Cold water is best
  • Never more than 8% sugar in your sports drinks
With the next post, we'll get to the salt.


Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC Jr. et al. American College of Sports Medicine position stand: Exercise and fluid replacement. Med Sci Sports Exerc 1996; 28(1): 1-7

Nutritional Aspects of Athletic Performance, Dr. James Meschino D.C., M.S., ND, 2008, Pages 20-24

Thursday, 25 August 2011

Caffeine and Athletic Performance

Remember last post, when I promised I would go over protein and athletic performance?  I lied.  Well I didn't think I did, but protein will have to wait because I just came across a very interesting study from 2010 published in the Annals of Nutrition and Metabolism.  If you don't feel like reading my entire article, I'll give you the 11 word summary: drink some coffee before a race, and you might go faster.

Is Caffeine Actually Allowed?

First, before we get into the the details of why and how to use caffeine, we have to establish if its use constitutes cheating.  Well, prior to 2004, if you had a certain amount in your urine, then you would have been accused of using a performance enhancing substance.  However, since then, it has been entirely taken off the World Anti-Doping agency's list of prohibited substances:

"The following substances included in the 2011 Monitoring Program (bupropion, caffeine, phenylephrine, phenylpropanolamine, pipradol, synephrine) are not considered as Prohibited Substances." -2011 Prohibited List, International Standard, World Anti-Doping Agency

So, if you decide to drink an extra cup of coffee to see what happens, you will not be breaking any rules by doing so.

Does it Actually Work?

For endurance activities, the short answer is yes.  A large number of studies referenced in the review below have shown that caffeine can improve performance in sport specific endurance events including running, cycling and cross-country skiing. 

By contrast, for high power/strength related tasks (such as sprints), there is no evidence showing that caffeine will help.  However, there is no evidence showing that it has a negative impact on performance either.  Essentially, (to coin scientists' favourite statement), more research is needed.

How Much?

So, you're an endurance athlete, and you're trying to decide how much to take.  This is the basic rule of thumb:
  • 2–6 mg per kg of body weight 1 hour before exercise
          • OR
  • 0.75–2.0 mg  per kg of body weight during exercise
These numbers come from the caffeine levels a majority of the studies used when showing caffeine had a positive impact on performance.  However, as you can see, there is quite a range, and thus it is very important to play around within these ranges to see what works best for you.  If you are a habitual coffee drinker, you will likely be at the upper end of the spectrum (6mg/kg) while if you rarely consume caffeine, you will be close to the 2mg/kg.

How Much is 1 mg??

Yeah, 1mg of caffeine does not mean anything to me either.  Here are some common dietary sources, and the amount of caffeine they contain:
  • Coffee 250 ml
    • Brewed100–150mg
    • Drip125–175mg
    • Instant 50–70mgTea
  • Tea 250ml 
    • Green (medium) 25–40mg
    • Black (medium) 40–60mg

  • Cola drinks 355 ml 35–50mg
  • Chocolate 50mg
    • Dark 20–40mg
    • Milk 8–16mg
So, how do you apply these numbers?  Well, for me, I am about 70kg.  If I were to attempt to use caffeine within the middle range of recommended doses, I would want to consume about  3mg of caffeine per kg of body weight.  Thus, I would want to consume 70kg(3mg/kg)= 210 mg total.

Thus, 1 hour before competition, somebody my size could attempt ingesting 210mg of caffeine, and could do so by drinking about 500ml of brewed coffee.  Not bad, many of us drink that much coffee to begin with anyway!

How Does it Work?

Disclaimer: This is the scientific section, I will not be offended if you skip it (this time). 

The classic studies on the beneficial effects of caffeine pointed toward the positive effects being related to caffeine's role as an adenosine receptor antagonist.  Adenosine receptors are found in a number of cell types throughout the body.  Speaking very generally, once they are activated, they have an inhibitory effect on the cell in question.  So, if we are talking about a heart cell, then the rate of contraction of that cell will decrease.  If we are talking about a cell containing fat, then it will cause that cell to retain and store more fat.

As a adensoine receptor antagonist, caffeine essentially will stop the adenosine receptor  from triggering the effect it is supposed to trigger.  In other words, it will stop that inhibitory influence from happening.  So, if we are talking about the fat cells again, caffeine will cause fat release into the blood stream and also discourage fat storage.  It was, therefore, thought that this would provide more fat readily available to be used to energy during exercise, sparing our carbohydrate stores.

However, more recent studies have shown that this may not be the case.  While it is true that caffeine will increase fat mobilization and decrease fat storage, these newer studies also show that this has no impact on saving our carbohydrates.  So, something else must be going on to account for the increased performance.

Looking beyond caffeine's influence on our fuel sources, one very prominent theory as to why caffeine works to improve performance is its direct impact on our nervous system.  A number of studies have shown not only that caffeine ingestion will result in a decreased perception of exertion during an endurance activity, but that it can also decrease how much pain an athlete experiences.  In other words, your central nervous system is wired, and you are less susceptible to mental fatigue.

My Thoughts

First of all, it is clear that caffeine at the ranges listed above likely does have a positive impact on performance in endurance events.  However, as you probably noticed, I did not mention how much of an impact it will have.  The reason for this is simple:  we do not really know.  The evidence is all over the place, some showing caffeine will have a drastic impact, lots showing it will have a minimal positive impact, while some showing that it will have an equivocal effect on performance.

If you are curious about how caffeine can help you, the best thing you can do it play around with different levels within the given ranges during training.  Experiment with what works best for you and your specific event, and stick to it.  Also, always pay close attention to side effects (such as rapid heart beat, tremors, upset stomach).

Before you decide to use caffeine, I also recommend thinking about why you are using it.  If caffeine works by stimulating your central nervous system, do you really need it, and do you really want to rely on it?  There are definitely other ways to get yourself pumped up and excited before and during a race (such as music, people cheering for you, and creating internal goals/sources of motivation).  But, either way, it might be a cool thing to experiment with! 


World Anti Doping Agency, 2011 Prohibited List, International Standard:

Ann Nutr Metab 2010;57(suppl 2):1–8

Tuesday, 9 August 2011

Nutrition and Athletic Performance: Part 1

What about Pizza?
Recently, I have had quite a few people ask me about various components of nutrition and its role in athletic performance.  The good news is that there is a huge amount of research on this topic, and the basic principals are very well understood.

Proper nutrition is extremely important in any sport, but undoubtedly becomes more important the longer the event lasts.  When I think back, it is almost comical when I count the number of races and training sessions that I have struggled through due to poor nutrition.  For instance, once during my cross-country days in university, I was busy with school and thus made the incredibly intelligent decision to skip eating to save time.  Then, when 3:30pm rolled around, I suddenly realized that,  "hey, I will need some calories to get me through the 4:00pm workout."  Well, my then 18 year old brain analyzed the situation, and came up with a seemingly flawless solution: 2 slices of greasy pizza (with copious amounts of dipping sauce, of course), and a coke.  Needless to say I bonked hard, barely finished the workout, and was left baffled.  Why did this nutrition strategy not work nearly as well as anticipated? 

Fortunately, since then I have learned exactly what it takes to optimize performance, especially in endurance sports.  Since it is a complicated issue, today I will talk about only one important component: carbohydrates.

How Much Should I Eat?
For endurance activities, carbohydrates are vital as they function as your primary source of fuel.  The amount of carbohydrates you consume during a regular training regimen is obviously quite variable depending on the training volume.  A general rule of thumb though is that you should ingest 6-10 grams of carbs per kg of body weight per day.    So, for me, I am about 71kg, so I need to ingest up to 710grams of carbohydrates per day.  That is about 32 pudding cups- delicious!

To get a more specific idea of how much and when you should be eating, first let's go through where your energy is coming from.   

When You Use What
Disclaimer: If you're bored by science, skip this section! 
It is important to understand that depending on how long your sport lasts, you utilize different sources of energy from within your body.  Here is a breakdown of when each fuel source kicks in: 
  1. Activities lasting 1-3 seconds (i.e. golf swing): Your body uses ATP already present.  ATP is essentially energy waiting to happen, ready to be used virtually instantly.
  2. Activities lasting 4-7 seconds (i.e. short sprint): You body again uses ATP along with the help of creatine phosphate (which basically helps to replenish depleted ATP levels)
  3. Activities lasting 10-30 seconds (i.e. hockey shift): Again ATP and creatine phosphate is used, but this time fast glycolysis is also used.  Fast glycolysis is the process of breaking sugar down that is readily available in your blood.
  4. Activities lasting 1-3 Minutes (800m run): Now your body not only utilizes sugar already in the blood, but it also taps into your glycogen stores.  Glycogen is essentially chains of sugar stored in your muscles and liver, waiting to be mobilized and used for energy.
  5. Activities lasting 3 minutes or more: You still are using sugar and glycogen, but you also start to tap into fat stores.  I will talk about this more in a future blog.

How To Eat Carbs Days Before
From above, it is clear that for any activity lasting more than 10 seconds, carbohydrates are extremely important.  In addition, any activity lasting over a minute, glycogen becomes a valuable source of energy.  For longer events (i.e. vigorous activity lasting 40-150 mins), about 70% of your energy comes from glycogen.  Thus, it only makes sense to pack as much glycogen into your muscles as possible prior to a competition.  This is the best way to do it:
  1.  During regular training, consume carbohydrates at a proportion of 60-70% of your daily caloric intake (this may go up to 80% if you train very long hours, i.e. for cycling).
  2. 4 days prior to competition, exercise to exhaustion while consuming a low carb diet (i.e. force yourself to completely deplete your carb stores).  This will not be fun!
  3. In the next 3 days, train easily, and consume a carbohydrate rich diet (up to 80% of your total diet).
  4. Do not train the day before competition.
This method has been shown to induce a phenomenon called super-compensation.  By implementing this method of carb loading, research has shown that the muscles are effectively able to hold 200% of the glycogen they normally contain.  Thus you have more glycogen, more energy, and as a result a longer lasting level of high performance.

How to Eat Carbs on Race Day
So after you have completed the perfect carbohydrate load by following the sequence above, now the question becomes; how do I eat the morning of a competition?  While there are many different things to consider, the one universal rule that should be followed is: eat your last large meal at least 3 hours prior to competition.  So, if your race is at 8am, make sure you are done breakfast by 5am.  Here's why:
  1. When you eat, the hormone insulin is released into your blood.
  2. Insulin's job is to signal the body to store the food that was just ingested (either in fat or glycogen).
  3. This is BAD for performance, because we need to access those energy sources as quickly as possible, but insulin is working against us, trying to store that food.
  4. However, in 2.5-3 hours post meal, the levels of insulin drop off, and the hormone will no longer inhibit your ability to access the carbohydrates 

So again, eat at least 3 hours prior to competition.  Well, at least now we know it was not my fault for being terribly slow was entirely insulin's fault.

How to Eat Carbs During
During an endurance activity, muscle breaks down carbohydrates at a rate of about 1g per minute.  Thus, consuming 30 g of carbs every 30 minutes is ideal.  Great sources of carbohydrates include sports drinks and power gels.  The reason why these sources are so effective is because they are composed of simple sugars that are quickly absorbed and subsequently utilized.  This is the one time in your life where sugar is the best thing you can possibly have, so take advantage of it.  It is important to stay away from fibre and fat as they both slow intestinal absorption of food, while fibre encourages water retention in the intestinal tract.

It is important to note that after your race begins, you should wait 30-40 minutes prior to ingesting any carbohydrate containing foods or liquids.  The reason for this, once again, is related to my arch-nemesis: insulin.  Essentially, if you eat too soon, your body will act as if it is in a fed state, and thus be reluctant to release glycogen and fat stores.  

The key things to remember from this article include:
  • Exercise to exhaustion and then carboload to maximize glycogen stores for competition
  • Do not eat within 3 hours of competition
  • After the first 30-40 minutes, consume 30g of carbs every 30 minutes during activity
  • A delicious greasy pizza consumed 30 minutes before training may feel right at the time, but apparently science says it is quite the opposite
There will be more to come on nutrition and athletic performance, next week I will discuss the importance of protein (probably).


 Burke L.M.  et. al. 2006. Energy and carbohydrate for training and recovery. J Sports Sci. 24:675–85. 

 Meschino, J.,  2010. Nutritional Aspects of Athletic Performance. Pages: 1-10

Saturday, 30 July 2011

Part 2: Getting Rid of Tendinosis

No Inflammation?

Last week's blog took a look at the main differences between a more acute tendon injury (tendinitis) vs. a chronic tendon pain (tendinosis).  How exciting was that?

In case you missed it, or are too lazy the go back and read it (which I would be), the key difference to keep in mind is that while tendinitis is associated with inflammation, tendonosis is not.  Therefore, your typical icing and anti-inflammatory medication will simply not do the job with a chronic tendon injury.   

Then how do you get rid of your pain?  To get this answer, we will go back to our 2005 study published in the Journal of Medicine and Science in Sports.

This study took into consideration one of the most common types of chronic tendon pain- Achilles tendinosis.  A typical conservative treatment protocol for this type of injury often includes eccentric loading of the tendon.  Eccentric loading simple means taking your calve muscle from its shortened position to its longest position while under a load.  In other words, you would use your uninjured side to bring yourself onto your toes, and then slowly lower your heel to the ground using the injured side.  

 Here is a video of eccentric Achilles tendon loading:
This pilot study looked at 15 people who had not responded to previous conservative treatment (including rest, anti-inflammatory medication, orthotics, change in shoes, physical therapy).  Each of these individuals were so desperate that they were on a waiting list for surgery.  While they waited for their surgery, they completed one last ditch effort to rehab the painful tendon.  This is the protocol they followed:
  • 3x15 repetitions of the eccentric Achilles tendon exercise 
  • Repeated twice per day, 7 days a week, for 12 weeks 
  • Did not avoid going into pain 
  • If no pain was experienced, the number of reps were increased to create pain

After these 15 subjects completed the 12 week program, this is what they found:
  • There was a significant decrease in pain  (81.2 to 4.8 on the VAS- a pain scale) 
  • All 15 subjects were satisfied with their progress 
  • In a long term follow up, only 1 subject showed recurrence and subsequently required surgery

These are absolutely amazing results.  While medication, changes in shoes, and physical therapy could not touch the pain, this simple 12 week exercise program almost entirely eliminated it.  These results were consistent with what was observed in the author’s clinic as 90/101 painful Achilles tendons showed positive response to this protocol. 

Why Eccentric Loading?

First of all, why is it important to eccentrically load the tendon?  Why can you not concentrically load it (i.e. just stress the tendon by going up on your toes) instead?  In a recent study referenced within this article, it was shown that:
  •  81% of subjects were satisfied with their progress while eccentric loading
  • 38% of subjects were satisfied with their progress with concentric loading
So, to get the best results, go with eccentric.  If you try it yourself on your healthy Achilles tendons, even you will see that the concentric motion is smooth and easy when compared to the shaky motion of eccentrically loading the tendon.   

How does Eccentric Loading Change Tissue?
There is no definitive answer to how eccentric loading changes tissue.  There is, however, three theories:
  1. Increasing Tendon Strength:  The first logical theory is that by stressing the tendon, it will result in a stronger tendon.  However, if this is the reason why it works, then why would concentric loading not work?
  2. Decreasing the Perception of Pain: This theory makes a little more sense than the previous idea.  As mentioned in my previous article, one interesting difference associated with a chronically painful tendon is that there is an apparent lack of inflammation, and high levels of a neurotransmitter for pain- glutamate.  Thus, it leads to the idea that the tendon may no longer be damaged, but your nervous system is still interpreting pain originating from this area.  With the stepwise increase in repetitions with the eccentric loading protocol, you are consistently training your tendons to tolerate more loading and more pain.  This theoretically trains your nervous system to recognize and process only normal levels of pain from that tendon.
  3.  New Blood Vessels:  The final theory is associated with what is going on with blood vessels surrounding the chronically injured tendon.  As you may remember from my last article, there is an apparent decrease in blood flow within chronically injured tendons.  However, this also means that there is an increase in new blood vessels trying to penetrate the tendon along with associated nerves.  It is thought that these new nerves sprouting may be what is responsible for transmitting the inappropriately high levels of pain.  The theory is that the eccentric training regimen traumatically damages the blood vessels and subsequently decreases the amount of new nerves traveling into the tendon.
To test the 3rd theory, the sclorising agent Polidocanol was injected into the injured tendon.  This drug is normally used to treat itching, pain, and even varicose vessels.  It works by damaging blood vessels and causes them to shrink.  Thus, theoretically, if new blood vessels and the subsequent nerves were responsible for the pain experienced with tendinosis, then Polidocanol should stop the pain.  And, believe it or not, this is what was observed- both in the short and long term follow ups!
Not for Everybody 

First of all, it is important to note that this rehab protocol only seems to be effective when the painful portion is close to the muscle.  If it is close to the boney attachment, eccentric loading my not be helpful.  In this study, it was found that only 10 of 31 patients with insertional Achilles tendon pain were pain free and satisfied after their 12 weeks of rehab.  So, make sure you know what type of chronic tendon pain you have before you put your faith in eccentrics!


First of all, keep in mind that the tissue and cellular biology behind the rehab of chronic tendon pain is in its infancy.  This article simply outlines ideas with some interesting yet nonetheless limited supporting research.  So take it all with a grain of salt.

However, what you can conclusively know from this research is that if your tendon pain has not resolved with the normal rest and anti-inflammatory measures after an extended period of time, then:
  1. It is likely that your tendon is hurting for a reason other than inflammation (so it is time to lay off the rest and NSAIDs)
  2. Conducting an eccentric loading protocol that stresses the tendon into a point of pain is definitely worth trying (especially before you consider surgery) 

Alfredson, H. 2005. The chronic painful Achilles and patellar tendon: research on basic
biology and treatment. Scand J Med Sci Sports. 15: 252–259

Wednesday, 20 July 2011

Is Your Achilles Tendon (or other Tendon) Your Achilles' Heel?

The Painful Tendon

A tendon is a portion of connective tissue that links your muscle to bone.  These bands of tissue are prone to injury, and it is highly likely that you have experienced some form of tendon pain in your life.  Overuse shoulder injuries, tennis elbow, patellar tendinitis, and Achilles tendinitis are all common types of tendon pain that you may have encountered.  

RICE Principle- May not be effective for chronic tendon pain
But what exactly is going on with these damaged tendons?  Why do some symptomatic episodes get better in a matter of weeks, while others linger for months?  The answer comes down to what is happening at a cellular level, and where your pain is actually originating from.  These answers will not only surprise you, but it will drastically alter how you look at your injuries and how you manage them.  Surprisingly, your good friend, the “RICE” principle (Rest, Ice, Compress, Elevate), may not be as effective as you once thought. 

The Fallacy of Overuse

It is a well known fact that tendon pain originates from overuse, right?  The avid tennis player suffers from tennis elbow because he plays too much- it’s common sense.  It is common sense that appeals to my logic, but unfortunately it’s wrong (sometimes). 

In a 2005 review article published in the Journal of Medicine and Science in Sports, it was shown that the origin of chronic tendon pain likely does not come from overuse.  This paper references studies which described individuals who suffer from chronic tendon pain and who are also entirely inactive.  In addition, another study shows that physical activity was not correlated with the typical cellular changes that are associated with tendon pain.  The authors suggest, “that physical activity could be more important in provoking the symptoms than being the cause of the actual lesion” 

Thus, physical activity and overuse plays less of a roll than we once thought.  So should you be resting your injuries?  Maybe not, especially if it is a chronic problem.  

The Fallacy of Inflammation 

Popular consensus regarding the origins of tendon pain is as follows: the tendon is used so much that it becomes injured, inflammation follows, and subsequently pain is experienced.  This cascade is, in fact, fairly accurate, but for only half of the story.  While this sequence does describe what likely happens with an acute tendon injury, new research shows that chronically painful tendons show no signs of inflammation. 

The same 2005 paper describes how when histological studies were conducted on chronically painful tendons, normal levels of the inflammatory mediators called prostaglandins were found.  If inflammation was occurring, these prostaglandins would have been observed at high levels, but they were not.  In addition, genetic studies showed that there was no upregulation of the genes responsible for producing inflammation.  In other words, there were no signs of inflammation, and no signs of triggers for inflammation. 
These may be of no help with chronic tendon pain

Another more practically applicable study referenced in this paper looked at the use of piroxicam, an anti-inflammatory medication, in the treatment of chronic Achilles tendon pain.  Interestingly, it showed similar results to placebo, and now we know why!  There was no inflammation for the piroxicam to get rid of, so of course sugar pills were just as effective. 

This also brings us back to the “RICE” principal.  The ice, compression and elevation components are all designed to decrease inflammation.  But, if piroxicam was ineffective in treating a chronically painful tendon, it seems that these methods would also provide little help for the same reason. 

Tedinitits vs. Tendinosis 

If you have experienced some form of tendon pain and sought a diagnosis from a healthcare practitioner (or Dr. Google), it is likely that you have been labelled with tendinitis.  It is funny because generally speaking, medical jargon has a habit of labeling a patient’s affliction by simply restating what they experience- only in a fancy way.  So, if a patient comes in saying that they injured their tendon and they feel like it is inflamed, the healthcare practitioner would give them the diagnosis of tendinitis.  However, this tremendously insightful diagnosis literally means tendon inflammation (“tendin-” means tendon, “-itis” means inflammation).

 However, as we just learned, in a chronically painful tendon, there is no inflammation involved, so tendinitis is no longer appropriate.  To take the place of tendinitis, tendinosis is now used. 
Suffer from chronic wrist pain?  Inflammation may not be involved!

What’s Going on with Tendinosis 

Glutamate Molecule- the primary suspect with tendinosis pain
Research is somewhat in its infancy in understanding tendinosis, but there have been a few key discoveries.  First of all, the study referenced below shows that glutamate levels were much higher in chronically painful Achilles tendons compared to normal tendons.  Glutamate is a neurotransmitter that is highly associated with the perception of pain.  So, if you’re hurt, and you feel pain, glutamate is playing a role in getting that single from your injury to your brain.  So it seems with these cases of tendinosis, even though the chemical inflammation is gone, there still seems to be some form of neurological inflammation sending the perception of pain to your brain. 

A second interesting finding noted in this article is that there was higher levels of lactate in chronically painful tendons compared to normal tendons.  Lactate is what you accumulate in your muscles when you strenuously exercise.  This happens because there is not enough oxygen reaching the muscles to meet the imposed demands.  So, in the case of tendinosis, it is speculated that the high levels of lactate indicate decreased levels of oxygen reaching the area as a result of reduced blood flow. 

So, in summary, two things may be going on with tendinosis: (1) your painful tendon may not be getting enough blood flow and/ or oxygen, and (2) your brain may be getting a pain signal from the tendon despite a lack of inflammation. 

 What does this do to Treatment?

What these pieces of evidence show, first of all, is why you should not get discouraged if you currently have a chronic tendinosis.  If you have been resting, and trying to control the inflammation with medication and ice, it is no surprise that you have experienced limited success.  This paper shows us why the tried and true RICE principle of treatment for acute injuries simply does not apply to cases of tendinosis. 

So what can you do to help these cases of tendinosis?  The details will be in next week’s blog, but the answer almost seems counter-intuitive.  The two keys of treatment include; (1) increasing specific exercises that stress the damaged tendon (rather than resting), and (2) conducting the exercises into pain (rather than avoiding pain).  Stay tuned!


Alfredson, H. 2005. The chronic painful Achilles and patellar tendon: research on basic
biology and treatment. Scand J Med Sci Sports. 15: 252–259