Are you drinking enough?

Hello friends, welcome back!  I apologize for the long layoff since a unique article has been posted on the blog.  Today's hits close to home as I have spoiled many-a-races via thinking I am too tough to drink sufficient fluids.  

Believe it or not...that millisecond you lose when you slow down to drink is actually a millisecond well spent.

This is especially true when your legs completely fall off due to profound dehydration rendering you unable to do anything but crawl to the finish line (and by you I mean me..and by crawl I mean drop out).

How much to drink? 

The only issue is that the amount you need to drink is completely variable depending on factors such as how hot it is outside and even your genetics.

Humans typically sweat at a rate of 1-2 litres per hour during sustained exercise.  But even that range doesn't apply to everybody-  Alberto Salazar (an ok runner, completing a bunch of sub- 2:10 marathons among other things!) has been quoted to sweat up to 4L/hour.

The American College of Sports Medicine recommends, in general, 5-8 ounces of fluids, every 10-15 mins (depending on the ambient temp and humidity), for events lasting more than 40-60 mins.

Those numbers are great, but there are two issues; (1) they include a large range of fluid recommendations and (2) how do you know if you fall in the upper end, lower end, or totally off the entire spectrum of normal (like our friend, Alberto)?

Study

A 2010 study published in the British Journal of Sports Medicine tries to answer this question of how to know when you are dehydrated, and understanding when you need to drink.

The BEST way to see if somebody is dehydrated is to (a) take a blood sample and measure the plasma osmolality (is it too concentrated?), or (b) take a urine sample and find the specific gravity (is it too concentrated?).

Unfortunately, most of us don't have the fancy equipment handy required to make these measures.  The second best method is to just go by body weight!  The more water you lose, the less you weigh.  In this study, researchers stated that if you lose MORE than 3% of your body weight, then you are clinically dehydrated.

However, during a race situation (or even our day to day lives), we don't always have the time to weigh ourselves before, during and after a bout of physical activity.  So how reliable are the other signs of dehydration?  This is what they looked at:

• reduced skin turgur
• sunken eyes
• mucous membrane dryness
• dryness of the axillia (armpit dryness)
• inability to spit
• heart rate
• blood pressure
• respiratory rate
• thirst

So lots of things can change as you become dehydrated.  But which of these are reliable measures of how dehydrated you really are??

Results

In the study, 606 runners were evaluated during a marathon taking place in New Zealand.  This is what they saw:

• reduced skin turgor had the strongest link to percent of weight loss
• sunken eyes and thirst were also linked to percent weight loss
• inability to spit and dry mucous membranes were not linked to weight loss
• combining the individual signs of dehydration did not improve dehydration evaluation

But, MOST importantly:

• the above clinical signs, in general, were not able to reliably predict the 3% weight loss cutoff point

What does this mean?

In essence, this study shows that these objective measures of dehydration simply do not tell you if you are dehydrated.  Looking to see if your eyes are sunken, if your face is less puffy, or if you are thirsty is undoubtedly linked to your body requiring more fluids.  However, the best way to know for sure (and if you don't want to test your blood and urine) is to weigh yourself pre and post activity.

Practical Application

Fluid is important to make you perform at your best!  The hotter it is outside, the more you sweat, and the more you need to drink.  So how should you approach your fluid status?  Experiment.  Start with that 5-8 ounces every 10-15 minutes on a training day that mimics your race climate.

Weigh yourself before and after; if you are losing over 3% of your body weight, you need to drink more...and if you don't, you will end up looking like AND performing like this guy:

Me not following my own advice

Why leaning forward might be making your low back pain worse

Welcome back readers!  Today, let me start out with a brief representation of a typical conversation I have had with a few devoted fans of the blog (and by devoted fans I mean people who I force to read it).

These fans will say to me something along the lines of, "Hey Sean, you blog about sports and science and stuff."

Trying to sound as intelligent possible I say, "Yeah."

Then they say, "Yeah, but, you're a chiropractor?

Again, delving into the recesses of my advanced vocabulary, I reply with, "Yup?"

They say, "Yeah, so why do you never talk about stuff relating to backs?"

Time to sound intellectual, clever and calculated.  I say, "Ummmmm."

There you have it; I don't know why.  I guess it all comes down to which article I have most recently read that is interesting or novel.  OR the topics are based on "fan questions" (aka. my parents ask me something).

However, I can't disagree with the idea of throwing in some articles relating to the back.  So, I will work on compiling some new and interesting research on back pain.  In the meantime I have something to tide you over.

I also write for the New Hamburg Independent, and below is one of my articles which was published in a mid-May issue.  It touches on a part of back pain that is often neglected, and may be part of the reason why yours is not getting better.  It is a basic summary, but a good start nonetheless, enjoy!

 Why leaning forward might be making your low back pain worse

Low back pain is an extremely common disorder that affects 8 out of every 10 people at some point in their lives.   In fact, 26% of adults in North America report some form of low back pain every three months.

More often than not, this pain is a result of damage and irritation to the joints, muscles, and ligaments in the low back.  In these scenarios, a general exercise regime with an emphasis on strength and flexibility is undoubtedly crucial to making a speedy recovery.

However, when the intervertebral discs are involved, this general exercise regime must be much more restricted.

The intervertebral discs are soft tissue structures separating the vertebrae that make up your spine.  The outer layer of the disc is composed of tough connective tissue, but the internal component to the disc (called the nucleus pulposus) is more jelly-like. 

When a disc injury happens, the outer layer of that disc can become torn, and the inner layer can subsequently protrude outside of the disc.  The most common direction this protrusion occurs is backwards and to the side.  The damaged disc itself can cause pain, but more importantly, this protrusion can cause pain via putting pressure on the nerve roots branching from your spinal cord.

Symptoms of a disc herniation include pain with coughing or sneezing, electric or burning pain traveling down your leg, and pain aggravation with leaning forward.

If your low back pain is related to the muscles and joints, activity helps to flush out inflammation that has accumulated, keeps the muscles strong, and helps to increase blood flow which aids the healing process. 

By contrast, with a disc problem, your activities need to be much more limited.  Specifically, you need to avoid leaning forward at all costs.

Picture the intervertebral disc as a tube of toothpaste; when you squeeze the end of the tube, the toothpaste will come out of the top.

By the same logic, when you are leaning forward, you squeeze the front of your intervertebral discs which causes the nucleus pulposus to travel even further outside of the disc.  

A common mistake patients make when dealing with back issues is to stretch into the direction of pain, falsely thinking that they are creating mobility in tight tissues.  However, when the pain is originating from a disc issue, rather than creating mobility, they are actually making the issue worse, putting more pressure on the nerves, and slowing the heeling process.  

In addition, when pressure is put on the nerve roots branching from the spine, pain can be experienced as symptoms in the back of the thigh.  Another common mistake patients make is to perceive this as hamstring pain, and try to solve the issue by stretching this muscle group. 

This is another activity that must be avoided.  The stretch will not only encourage forward bending in the spine which worsens the disc issue, but will also put tension in the already irritated nerve, aggravating the leg pain.

So what can you do to help manage back pain relating to disc issues?  The answer is undoubtedly multifactorial, but avoiding bending forward at the low back is of the utmost importance. 

Run Group Information

Hello Readers!

I usually try to keep my posts strictly about the research behind health and performance.

However, I just wanted to take this opportunity to let you all know about the 3 major run groups that Health and Performance leads.  In the future, you can find group information on the Health and Performance Training Website.


(1) NEW Learn to run group

• A non-threatening way to introduce yourself to the sport of running
• 8 week program with weekly seminars on how to become a runner, and how to keep being a runner long term
• This program will set you up so that you are equipped to run 5km races 
• It will prepare you for the other two groups led by Health and Performance
• For more information about this group CLICK HERE

(2) Monday Night Interval Sessions

• Every Monday at 6:30pm at the Waterloo Rec Complex
• Free!
• Middle and long interval sessions on undulating terrain
• A mix of hill work
• High intensity, and a great way to improve your speed and fitness
• All levels welcome

(3) Wednesday Night Track Sessions

• Every Wednesday at 7:30pm now meeting at the Resurrection high school track (as of March 21st)
• Free!
• Shorter distance track workouts
• Stride drills and dynamic core work is sprinkled within the workouts
• A great way to improve foot speed and stride efficiency
• All levels welcome

There you have it!  So if you are looking to take your performance to the next level, or just starting to run for the first time, one of our run groups should work for you.  Each of the groups have a great team atmosphere, and we are all there to support each other regardless of your level.

If you have any additional questions about the groups, do not be afraid to e-mail me: seandelanghe@gmail.com 

Marathons and Knee Cartilage

Here we go again!  For my regular readers, as you know, I ran a marathon way back in November on not nearly enough training.  The race itself was great, but my knees tended to disagree with the decision for about 6 weeks after the race.

From that point on, I have been curious about the actual impact (pun intended) running has on knee cartilage.  Obviously some damage takes place over the course of 3+ hours of running, but is this damage irreversible?

Arthritis and Running

While studying at chiropractic school, it was made very clear to us that moderate levels of running are not associated with an increased incidence of knee arthritis.  Factors such as genetics, trauma, and BMI are much more strongly correlated with developing osteoarthritis of the knee.

However, the studies we reviewed in school were typically epidemiological in nature (they often looked retrospectively at these various risk factors in large populations, and then looked at the incidence and severity of knee arthritis in the same population).  These studies are great, but they fail to look prospectively at how a knee responds to a strenuous bout of running.

Because of this, I was still curious about how ONE marathon could impact the cartilage within a knee.  That's when I came across this study published in 2010 in the American Journal of Sports Medicine.  I should mention that I was exposed to the study via Research Review Service which is a great resource for all manual therapists.

The Study:

Past studies have looked at the acute impact of long distance running on knee cartilage using an MRI- some show no changes, others show some transient changes.

This 2010 article is so great because it used new methods of quantifying the cartilaginous changes that happen- the researchers were able to assign specific numbers to rate the changes that took place during the marathon.

Design:

10 runners were followed during this study.  They were selected based on a number of factors, two of which included the fact that they had never run a marathon before, and were active 30 minutes or less per day.  These subjects were not runners!

Without getting into the details, the two outcome measures used in this study included:

•  T1ρ- measures damage to the collagen-proteoglycan matrix (i.e. the protein and carbohydrates that link together and make up the structure of the cartilage)
• T2- collagen orientation and water content (i.e. is the protein in the right position, and is there enough water in the cartilage?)

The runners were tested before the marathon, 48 hours after, and then during a 3 month follow up.


Results:

• The T1ρ values (looking at damage to the protein and carbohydrates):
• Significant changes beneath the knee cap AND throughout the middle aspect of the knee
• These changes were seen at both the 48 hour and 3 month mark

• The T2 values (looking at collagen orientation and water content):
•  Significant changes beneath the knee cap AND throughout the middle aspect of the knee
• These changes were seen at the 48 hour mark
• The changes were seen to a much lesser degree at the 3 month follow up

The control group (i.e. same tests, no marathon run), showed absolutely no change in their T1ρ or T2 values throughout the study.

Explanation:

So what does this show?  Essentially, if you aren't trained, and you have never run a marathon before, you can expect to see some lasting damage to the cartilage in your knee.  This damage comes in the form of loss of water content as well as having a negative impact on the protein and carbohydrate structure of the cartilage.

This study also shows that while the damage to the proteins and carbohydrates persist 3 months later, the water content within the cartilage seems to return to baseline levels.

Limitations:

While very interesting, as with most research, there are limitations to this study.  It is important to keep in mind that these were untrained runners who ran a marathon, and then preceded to not train after the race.  Would the same degradation have taken place if they had trained properly beforehand?  Would the rate of recovery improve if they had continued to train after the race?  Would we still see the same changes 6 months or 1 year down the road?  These are all questions that this study fails to address.

That being said, it is a great preliminary round of research on the impact of marathons on knee cartilage.  It generates a plethora of questions that hopefully can be addressed in future, more comprehensive studies.

Take Home:

Running a marathon (and the training for it) definitely causes acute degradation of the articular cartilage in the knee.  This study also shows that there is a possibility that these changes persist long term.

Nevertheless, the health benefits of running for the general population (with no underlying conditions or risk factors) undoubtedly exceed the risks.  This study should not discourage you from running.  If anything at all,  this study should encourage you to incorporate a diversity of cross training to complement your running regime.

Core Strength and Run Performance

Hello readers!  Of "cores," it's that time again, welcome "back" (funny, I know)!  Before we get started, make sure you check out and like the NEW Health and Performance Facebook Page- I'll be using this page to post information on new run groups, race information, training tips, race pictures etc. 

Today I am looking into something that many endurance athletes ask me about- the importance of core exercise.  Does it really have a positive impact on performance, or is it a waste of time?  That's what I am taking a quick look at with today's blog.

The Research:

There are plenty of studies out there looking at the relationship between core training and running.  Many of these studies have a similar design- two groups of runners with small sample sizes doing a basic core routine along with a few running related outcome measures.  In my search, I came across this study published in 2009 in the Journal of Strength and Conditioning Research.

The study looked at a 6 week core routine consisting of 5 exercises conducted 4 times/week.  The outcome measures used in the study included:

•  Star Excursion Balance Test (testing balance)
• Ground Reaction Forces during different components of their gait cycle (i.e. is there more force during push off? more force during heel strike)?
• 5000m Time Trial

Results:

After the 6 week program, the authors noted that there was improvement in the balance test.  However, this improvement was seen to the same statistical significance in both groups.

In addition, the core training did not have a significant impact on the ground reaction forces observed throughout the runners' gait cycle.

Yet- the most exciting part- when the 5000m TT results were considered, the core training group showed a statistically significant improvement when compared to the control group.  In fact, the core training group improved by an average of 47 seconds compared to 17 seconds for the control group. 

What does this mean?

It's pretty obvious: do some simple core work, and you'll go faster.  There are a number of studies out there trying to deduce why this change happens.  Is it because it has an impact on running economy such as this 2004 study examines?  We're not completely sure.

While it would be nice to actually know WHY something works, at the end of the day it is more important to know if it works.  This study shows that core training may not significantly alter your biomechanics, and it may not have a significant impact on your balance (if you are already a trained athlete), but it will likely make you faster. 

Which to do?

In the study, the 5 exercises they conducted included:

1. Stability ball abdominal crunch
2. Back extension on a stability ball
3. Prone 1-arm, 1-leg raise
4. Hip raise on a stability ball
5. Russian twist on a stability ball

While these exercises are fine, they do have their risks.  Researchers have shown that the safest way to load the core (thus the low back) is when you are in a neutral position.  I'm sure many of you have heard this before, but if you lose that subtle curve in your low back, you are going to be putting unhealthy forces through your intervertabal discs (if you are leaning forward), or your facet joints and posterior elements (if you are leaning back).  You can definitely get away with some movement while doing your core work, but the safest course of action is to keep things rock solid in that neutral position.

3 great exercises proven to be effective, to complement each other well, and to be extremely safe are (click to see a video of the exercise):

1. Bird Dog
2. Front and Side Planks
3. McGill Crunch (go 1:25 into the video)

There are more advanced exercises that keep the spine neutral, but master these before you move on.  Feel free to comment or e-mail me if you're looking for suggestions that are safe.  Also, watch the man behind these exercises explain why they are healthy and effective, and why some of your conventional choices may not be: Stu McGill

Conclusion:

While the study I discussed IS only one study with a sample size of 20, what it does show is that by adding a simple core routine, you'll probably go faster.  Why does this happen?  I'm not sure, and the research isn't sure either.  But, at the end of the day, if speed is what you crave, then I wouldn't hesitate to add a regular core routine to your training schedule.

The Toronto 10km Saga

Hello readers!  Usually I blog about the science behind health, fitness and training.  Today I am writing about a topic that is somewhat different, but important in that it seems to be having a significant impact on our running community.  

For the past 26 years, there has been a Toronto 10km.  For the past 14 years of the race, it has been under the name, "Sporting Life 10km" as Sporting Life has been the key sponsor.  This year, things have changed.  There are now two races: The Yonge Street 10km and The Sporting Life 10km.  So which to chose?  And why is there a split?  With this blog, I am going to try to explain both sides of the story from an unbiased perspective.  Keep in mind, I am not a journalist, just a curious recreational runner.    

The Facts

The initiating factor in the split stems from the two marathons that are held in Toronto: the Scotiabank Toronto Waterfront Marathon and the Goodlife Toronto Marathon.  Originally both took place in the fall, but an agreement by both parties along with the city brought the Goodlife Toronto Marathon to the spring (early May).

This created conflict because the Toronto Waterfront Marathon is a Canadian Running Series (CRS) event as is the Yonge Street 10km (formerly Sporting Life 10km).  Part of the agreement was that while the Goodlife would move to early May, the CRS series would not hold another event within 2 weeks of the new Goodlife marathon date.  As a result, the 10km would have to be moved either to late April or later on in May. 

Sporting Life's Point of View

The main issue that Sporting Life publicly states is that they were not consulted with regards to this change of date.  

In an article published in the Toronto Star David Russel, co-owner of Sporting Life was quoted saying, "We were aghast that he would do that ... It was cavalier and put our race in jeopardy."

A statement on the Sporting Life 10km website echoes these sentiments. "Unfortunately, the agreement was made by CRS without the knowledge or agreement of either Sporting Life or Camp Oochigeas and without regard as to how this would impact fundraising for the charity."

In essence, Sporting Life felt blindsided by the move.  I can definitely understand these sentiments to some extent.  With 14 years of sponsorship and commitment to the CRS, feeling entitled to some control of the race does seem reasonable at first glance.  But, as you know, there are always two sides to a story... 

Canadian Running Series' Point of View

I had the pleasure of chatting with CRS director Alan Brookes online to clarify some of these issues.  I truly believe he gave me honest answers which revealed the underlying motivation for the split that stems far deeper than the marathons.  The split did not occur because of a simple date change, but from a constant struggle of differing opinions regarding the direction the race was headed long term.

Mr. Brookes made it clear to me during our conversation that the CRS is committed to producing events centered around a complete runners' experience along with encouraging elite runners to pursue excellence. 

In addition, there is also a strong charitable component to the CRS as Brookes told me that, "last year our races [and YOU runners!] raised over $6.5 million for 238 charities."

However, rather than pursuing running excellence in conjunction with strong ties to various charitable causes, Sporting Life wanted to make the race all about the charity with a lesser focus on the runners.  Essentially, their vision was a run for the cure. 

This is consistent with a statement on the new Sporting Life 10km website stating, "This year, for the first time, 100% of race net proceeds will benefit Camp Oochigeas."  

Why Does a 'Run for the Cure' Concern the CRS?

Does this mean that the CRS is anti-charity?  Not even close.  As you can see from the numbers above ($1.3 million raised at last year's 10km, $6.5 million last year total), the CRS not only values charity, but excels at contributing to these causes.  

Brookes told me, "My only concern with charity runs is that they can come and go - like Sunnybrook Run for Research or Baycrest 10K...we are all about the sport and putting on the very best events for the running community. We'll always be here for you."

So at the end of the day, Brookes sees the race as having a focus on running excellence and an exceptional race experience.  This will, in turn, lend to the lasting power of the event, and ultimately maximize the charitable donations.   

Other Motivations?

Is Sporting Life really doing this exclusively to fight for Camp Oochigeas?  Let me be clear, it is nothing short of incredible what the CRS and Sporting Life have done to contribute to this cause over the years.  If more corporations contributed this way, who knows how this could impact our society.  Yet, at the end of the day, Sporting Life is a business, and thus business oriented motivations are also at play.  

For instance, Brookes informed me that, "ourselves and New Balance wanted to move the packet pick up out of the Sporting Life store for more space, a mini-expo experience, and better race experience. Sporting Life didn't want that."

So CRS wanted a mini-expo for the runners, while Sporting Life wanted publicity for their store.  I really can't fault either side here (really, I think both sides have extremely valid motivations).  However, it just shows that (a) the CRS was fighting for the runners and (b) Sporting Life was fighting to optimize publicity for their business (why else would they be a sponsor?).

So is Sporting Life really all about the charity?  The work they do for the charity is amazing, nobody disputes that.  But, at the same time, working for a charity is great for PR...as is having the race kit pick up on site at the store.  

So Who Is Right?

After the split between the CRS and Sporting Life, there were a few things that transpired that are less then honourable.  However, the facts I revealed above show the motivation for the split, which really is all that matters in the end.

Sporting Life wants a great race all about charity that simultaneously works toward improving publicity for their company.  That makes sense to me; contribute to charity, have a great race, and improve your business at the same time.

Alan Brookes and the CRS, by contrast, wants to work toward an event centered around the runners and the race experience while still making significant contributions to charity.  That also makes sense to me; give a place for elite runners to compete, create a great race environment for all other runners, and still contribute to charities.

So who is right?  Well, at the end of day, it seems like both sides are pursuing noble causes.  However, it also is very obvious that both sides had very different goals, and when there is not enough overlap, then it only makes sense to part ways. 

My Biased Opinion

I am definitely not anti charity.  Are any of you?  I have volunteered at after-school reading programs for kids, Big Brothers of Canada, coached track teams, ran science programs, and the list goes on.  

However, I think Alan Brookes hit the nail on the head when he expressed his concern with the lasting potential of a 'run for the cure.'  If a charity finds a better way to make money, then the charity will take that route, and the race will be gone.  

I am happy to be part of a race that works toward a noble cause.  But to attract 15 000 people to a race annually, I believe more than a noble cause is required.  It needs to be fun and exciting.  I am excited to participate in an event where I can run 35:19 and still get beaten by over 7 minutes by two Canadian Olympic athletes.  How cool is that?  This runner's experience is what the CRS works hard to develop, and is why it will last (and thus, the benefits to charities will also last).  

Then again, there are lots of people out there who aren't running fans like myself.  Maybe their opinions would be much different!  

Which to Race?

So which race should you go with?  I don't really have an answer to that...how about to make it simple, everybody just does both.

Does Stretching Work?

I had a revelation today while partaking in my daily yoga routine- I am, by far, the most inflexible person in the world.  Hands down.  

Just kidding, I don't do yoga.  I really do not stretch either.  But, maybe I should...then I could be just as awesome as this guy.  I highly recommend you click on that link- the man is amazing!  If there are people like that in the world, then why can't I even touch my toes? 

Anyway, if you're like me, and you don't stretch, are we doing ourselves a disservice?

Well, the answer is a little complicated, but that is what I want to explore with today's blog.  Also, I should mention that I was first exposed to some of the articles referenced in this article at sweatscience.com (if you haven't checked it out, you should).

Does it help muscle soreness?

One of the most common reasons why people stretch is to reduce muscle soreness.  In preparation for (or to recover from) a hard workout, it is common practice to throw in some stretching to try and reduce how sore we feel the next day.  But, does this really work?

A 2011 study published in the Cochrane database  holds the answer to this question.  If you have never heard of the Cochrane database before, check it out- it is essentially where all the highest quality health care studies are pooled together to look for consistencies (or inconsistencies) in their results. 

In this review, 12 studies were included.  With a high level of consistency, the studies showed that pre-exercise stretching reduced soreness by about 0.5 on a 100-point scale.  In addition, post exercise stretching reduced soreness by a whopping 1 point on the 100-point scale.

So what does this show?  Well, if you are stretching acutely before or after an activity to reduce soreness relating to that specific activity, you are probably wasting your time.  That does not mean stretching is useless (we will get to that), but it just means that it does not fulfill this use.


How does stretching impact performance?

Well, it is widely accepted now that stretching decreases performance in power or strength oriented events (like jumping, shot put, power lifting, sprinting).

That being said, how many of you still stretch prior to participating in endurance events?  If you do, maybe you shouldn't.  Some relatively new research shows that stretching may also  decrease endurance performance.  This 2010 study looked at the impact of static stretching on endurance running.

In the study, collegiate runners were put through 2 separate 60 minute time trials; 1 with stretching before, and 1 without stretching.  The 60 minutes were separated into two components:

• First 30 mins: the running intensity was was kept at a constant (65% of their VO2 max)
• Second 30 mins: the runners were told to go as far as they possibly could

Interestingly, this study showed that on both accounts, the non-stretching trials out performed the stretching trials.

•  First 30 mins: the non stretchers burned significantly fewer calories than the stretchers (425 vs. 405 kcals) 
• Second 30 mins: during an all out effort, the runners went 3.4% further when they did not stretch

What does this show about stretching?  Well, if you do it before an endurance event, it will have a detrimental impact on your performance.  On a side note- keep in mind that this study was looking at static stretching only.

Does stretching reduce injury?

Stretching has to be good for something, doesn't it?  How about preventing injury?  This study, which is comprehensive review article, shows that the evidence is pretty inconsistent when it comes to the role of stretching and injury prevention.

This uncertainty arises because many of the individual studies referenced show that stretching has no impact on the frequency of injuries.  Check out this full text article which shows that among 1538 army recruits, their regular stretching regime had no impact on the frequency of injuries.

So does stretching help prevent injuries?  These studies suggest that in general, it does not.  However, there may be more to this than meets the eye.  So before you give up on stretching forever, keep reading...

My take on stretching and injuries: 

The above research does cast a shadow on the role of stretching in preventing injuries.  However, there is one key flaw that all of these studies fail to take into account: the cause of and the type of injury.


For example, there are many studies showing that stretching alone has very little impact on low back pain.  Does this mean that stretching is never good for low back pain?  No.

One thing that should be kept in mind when interpreting stretching and low back pain research is that there are a number of causes for low back pain. If your low back pain is originating from an instability (or too much motion), then why would stretching help? By the same logic, it would seem that the hypomobile painful back (stiff, not enough movement) may be more likely to respond to a stretching regime. Unfortunately, these two types of low back pain are not separated in the studies looking at stretching as an intervention.

So, some subjects might see benefit (probably the hypomobile individuals), and some subjects might feel worse (probably the overly flexible group).  Unfortunately, this averages out to the conclusion: stretching does not have an impact on low back pain.

The solution to this problem comes down to classifying injuries into different subsets before accurate conclusions about specific interventions can be drawn. This is where the research is headed, but we are still trying to figure the best classification system out.  For instance, check out this example for the classification of low back pain.

Conclusions:

Here are your takeaway points:

• Stretching does not reduce post exercise muscle soreness
• Stretching has a negative impact on both strength and endurance oriented activities
• Stretching is not good for ALL injuries (but is potentially very useful for some). 

At the end of the day, I hope this article helps prevent some of you from stretching for the wrong reasons.  But, I also want to make sure you are not scared to stretch- there are benefits (but maybe just not as many as we once thought)!  For instance: squeezing into a box.

Compressport

I'm looking forward to using some gear from compressport for the 2012 season!  They have lots of cool stuff, check out their site by clicking here.

But do compression socks (or other sources of compression) actually help enhance performance and/or recovery?  Stay tuned for my next blog!

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.

Study:

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:

PHASE 1

• 74g chocolate containing 22g of cocoa
• 74g placebo chocolate containing 0g cocoa

PHASE 2

• 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!

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.

Study:

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. 

Conclusion:

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).

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). 


Results:

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.

Reference:
Click here for the article

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:

The Pose Method of Running Video

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.

Conclusion: 

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.


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

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"
• Published Medicina Sportiva (2010)
• 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?


Jeremy:   
"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? 

 Jeremy:
"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?

Jeremy:
"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?   

Jeremy:
"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?


Jeremy: 
"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."


Closing:
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.

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.

Sodium

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.

Potassium

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. 

Closing 

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!

References:

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

2) National Institute of Health: Office of dietary supplements. http://ods.od.nih.gov/ Accessed Sept 27th, 2011

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



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.

Summary

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.


References:

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

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! 

Sources:

World Anti Doping Agency, 2011 Prohibited List, International Standard: http://www.usada.org/uploads/2011-full-prohibited-list.pdf

Ann Nutr Metab 2010;57(suppl 2):1–8

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 post-pizza...it 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.  

Conclusion

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).

References: 

 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