Enjoy your fitness

My brain is pretty lucky.  It gets to ride around in my head while my legs take us to wonderful places.  For example, running up Long’s Peak to Chasm Lake in Colorado last year was physically painful, but the visual pleasure achieved as well as the emotional rewards of the task easily outweighed the challenge.   It was a simple case of my body being strong enough to take my mind to wonderful places.  Perhaps that is one of the most rewarding parts of ultrarunning, I call it enjoying my fitness. 

Beyond the visual and auditory stimulation my brain enjoys from extreme physical challenges, the brain is also rewarded by a “running high.”  It is amazing how great my brain gets to feel after a good long run.  This happened last weekend after meeting up with a group of runners who are all preparing for the North Country Run.  As the herd of us moved through the woods with our headlamps shining, I could already tell that it was going to be a fun day.  There is something special about starting in the dark and watching the sunrise.   Sure, there were parts of the run that were absolutely terrible, mostly during the part when we were attacked by clouds of hungry deer flies.  In fact, half our group decided it was too much and headed out to finish their run on the roads.  But this is where the fun started.  With a smaller group, now moving more quickly, we logged another 16 miles in just a touch over 3 hours AND the flies never came back!  I think it had something to do with running through the trails at sunrise that made them so vicious.  Towards the end of the day Jason Robertson and I decided to race up every hill we could find.  According to Jason these were “uphill death races” although I felt like a small child goofing around with my friends. 

When the run was over I got an incredible adrenaline rush and just let out a cry of pure joy.  Not only had we overcome the insanely painful flies, but had pushed ourselves hard when we were most tired.  This run, together with some other runs I have had recently has really made me appreciate what amazing machines we can build our bodies into.  Ultrarunners in particular have to deal with a tremendous amount of pounding, burning through thousands of calories which has to amount to incredible amounts of metabolic stress, and just general abuse from doing what we love.  But then you get rewarded as this lump of tissue in your skull (your brain) becomes soaked in endorphins while the legs keep on taking step after step after step. 

Enhancing Fatty Acid Oxidation in Skeletal Muscle

PPAR attention to this!

In this blog I hope to discuss training practices used by athletes in order to maximize the results seen from hours upon hours of aerobic training.  Both running and cycling coaches often suggest occasionally training in the fasted state to their athletes.  Also, several nutrition companies suggest very small meals or skipping breakfast on race day in order to maximize fatty acid oxidation during endurance racing.  Thus my goal is to discuss the reliability of these suggestions, as well as propose an exciting potential mechanism.

During endurance exercise contracting muscle fibers rely on a mixture of metabolic substrates to provide energy.  Different types of muscle fibers rely more heavily on different fuel sources.  Glucose serves as the preferred energy source in type IIa (fast twitch) muscle fibers, while type I (slow twitch) muscle fibers rely more heavily on lipid metabolism (1).  Submaximal endurance exercise in particular recruits mostly type I fibers, indicating that there is the potential to rely on fatty acid oxidation as an energy source for endurance sports (2).  Intramyocellular triacylglycol (IMTG), lipoprotein-derived triacylglycerol (TG) and plasma free fatty acids (FFA) are proposed to be the source of lipids oxidized by type I fibers (3).  Indeed, trained athletes accumulate IMTG and rely more heavily on fatty acids to provide energy if exercise is performed in the fasted state, rather than the postprandial state (1, 4). 

Training in the fasted or glycogen depleted state has the potential to alter the metabolic machinery within type I muscle fibers.  Several studies indicate that consistent training in a glycogen depleted state generally results in increased capacity of muscles to oxidize fatty acids through changes in enzyme activity, fatty acid transporter proteins, and gene expression resulting in increased fatty acid oxidation by mitochondria (1, 5).  Interestingly, athletes utilizing carbohydrate depletion training methods also show improved ability to resynthesize muscle glycogen post-exercise (1).  The implications to athletes are substantial, considering that this training may also facilitate glycogen sparing when carbohydrates are consumed during a race (6).  Thus not only would an athlete start a race with optimal muscle glycogen content, but also be able to protect these stores until race conditions demand their use, such as a sprint finish.

Perhaps the most interesting studies examining the impact of increased fatty acid oxidation capacity on endurance exercise were performed using transgenic mice expressing a constitutively active form of the nuclear transcription factor peroxisome proliferation-activated receptor (PPAR) δ.  These mice have been affectionately named “marathon mice” due to the fact that they are able to run twice as far and twice as long as their wild type littermates (7).  PPARδ, also known as PPARβ, is the least studied of the PPAR isoforms, but is the predominate isoform expressed in muscle tissue and its expression is thought to be linked to increased capacity to oxidize fatty acids by mitochondria (7, 8).  Most highly expressed in type I muscle tissue, targeted overexpression of this transcription factor in muscle leads to muscle fibers switching to a type I phenotype.  Furthermore, treatment of wild type mice with a PPARδ agonist induces changes in gene expression similar to targeted overexpression of an active form of the transcription factor (8). 

Endurance training as well as fasting has also been shown to upregulate PPARδ expression and in both mice and humans, resulting in increased capacity to metabolize fatty acids by skeletal muscle (7).  This interesting PPAR provides at least one potential target to increase endurance capacity in both amateur and elite athletes as well as in individuals suffering from metabolic syndrome.  PPARα and PPARγ agonsists are already used in the treatment of hyperlipidemia as well as insulin resistance, respectively.  Interestingly, “marathon mice” are protected from high-fat-diet induced obesity and exhibit improved glucose tolerance compared to wild type controls.  Because of the ability of PPARδ to induce a type I muscle fiber phenotype and enhance skeletal muscle fatty acid oxidation, pharmacological activators have the potential to be an “exercise pill” that can enhance beneficial metabolic gains acknowledged to be a result of endurance training.

Works Cited

1.         De Bock K, Richter EA, Russell AP, Eijnde BO, Derave W, Ramaekers M, Koninckx E, Leger B, Verhaeghe J, Hespel P. Exercise in the fasted state facilitates fibre type-specific intramyocellular lipid breakdown and stimulates glycogen resynthesis in humans. J Physiol. 2005 Apr 15;564:649-60.

2.         van Loon LJ, Greenhaff PL, Constantin-Teodosiu D, Saris WH, Wagenmakers AJ. The effects of increasing exercise intensity on muscle fuel utilisation in humans. J Physiol. 2001 Oct 1;536:295-304.

3.         van Loon LJ, Koopman R, Stegen JH, Wagenmakers AJ, Keizer HA, Saris WH. Intramyocellular lipids form an important substrate source during moderate intensity exercise in endurance-trained males in a fasted state. J Physiol. 2003 Dec 1;553:611-25.

4.         van Loon LJ, Koopman R, Manders R, van der Weegen W, van Kranenburg GP, Keizer HA. Intramyocellular lipid content in type 2 diabetes patients compared with overweight sedentary men and highly trained endurance athletes. Am J Physiol Endocrinol Metab. 2004 Sep;287:E558-65.

5.         Van Proeyen K, Szlufcik K, Nielens H, Ramaekers M, Hespel P. Beneficial metabolic adaptations due to endurance exercise training in the fasted state. J Appl Physiol.  Jan;110:236-45.

6.         De Bock K, Derave W, Eijnde BO, Hesselink MK, Koninckx E, Rose AJ, Schrauwen P, Bonen A, Richter EA, Hespel P. Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake. J Appl Physiol. 2008 Apr;104:1045-55.

7.         Ehrenborg E, Krook A. Regulation of skeletal muscle physiology and metabolism by peroxisome proliferator-activated receptor delta. Pharmacol Rev. 2009 Sep;61:373-93.

8.         Wang YX, Zhang CL, Yu RT, Cho HK, Nelson MC, Bayuga-Ocampo CR, Ham J, Kang H, Evans RM. Regulation of muscle fiber type and running endurance by PPARdelta. PLoS Biol. 2004 Oct;2:e294.

Salomon Fellcross Review Preview

Being a huge fan of the Salomon Speedcross 2, I was hugely excited for the updated Speedcross 3, especially since Salomon has reduced the heel to toe drop in the SC3.  Upon doing research for the SC3 I stumbled upon an intriguing new shoe being built by Salomon.  Enter the Fellcross.  Similar in design to the super successful Speedcross, the Fellcross builds upon a very similar platform.  The Fellcross is advertised to be built for fell racing, a type of trail running popular across the pond that from what I understand consists of lots of mud, as well as steep ups and downs.

Awesome traction from this heavily lugged outsole

What really caught my eye about the Fellcross was the 6mm heel-toe drop advertised by Salomon and confirmed by runningwarehouse.com.  This shoe seems to maintain the solid build that Salomon shoes are known for, yet still carries very little weight (10.2oz).  It feels super durable, and while the lugged outsole is similar in appearance to the Speedcross, it seems to be made from a firmer rubber that seems to wear more slowly than the Speedcross.  To be honest, I only got these shoes yesterday, but I am already very impressed.  After signing up for Oil Creek this week I decided that I needed a more protective, cushioned shoe to use in a rugged 100 mile trail race, I still love my mt101s, but after getting knocked around a bit on some rocky descents last weekend I decided I wanted a little more shoe for rugged terrain.

I can't fold my Speedcross2 like this!

Yesterday I took the Fellcross to my local training grounds and ran 15 miles while jumping on top of roots I usually avoid and trying to find sharp rocks to step on.  A little masochistic I know, but I wanted to test the protective nature of these shoes.  I did the same 15 mile loop today and was again very impressed with the amount of protection afforded by the Fellcross.  They handled everything I could throw at them, but I will take them to the Potawatomi for the true test.  I hope to update this review once that is complete.  I can already tell this shoe EXCELS at providing excellent traction in sand as well steep climbs on rocky trail. 

***  I have put in just over 100 miles in the Fellcross now and I am still very happy with my purchase.  Longest run so far has been 27 miles and I never felt irritated.  I have even taken them climbing on the treadmill!  Much more comfy ride on the treadmill compared to the speedcross 2.  Only new complaint is that they quicklace system must be tucked tightly behind the tongue as the tongue is much more compact than the speedcross***

Compared to the Speedcross 2 the Fellcross is much much more flexible, and importantly for my gait, allows a much cleaner forefoot/midfoot landing to promote a quick cadence.  This is the shoe that the Speedcross 2 should have been.  Even with the low heel to toe drop these shoes still bomb downhills like the Speedcross 2, but due to the firmer rubber lugs, dont have quite the amount of cushion.  I think they might run a little large, but I am comfy with a small amount of room to spare in my normal size 10.5.

Crease forms that can rub the arch the wrong way.

My only complaints about this shoe is that if the Salomon quicklace system is pulled too tightly a crease develops between the midfoot overlays that caused me to blister slightly, this was remedied after loosening the shoes a little.  I always quicklace my Salomon shoes too tight :).  The biggest downside to the shoe is the pricetag.  Being in Salomon's S-LAB series, this shoe retails at 160$$$$.  I picked my pair up for 115$ using the runblogger discount from runningwarehouse.  I guess in the shoe business you can pick any 2 of the 3.  Light, Comfortable, and Cheap.  The Fellcross gets the first two!

*****  My Fellcrosses lasted all summer and all fall.  In total I think I put around 1200 miles on them.  The upper and outsole are still in great shape.  I did notice that the midsole became a little bit softer over the miles and the lack of a rockplate began to be noticed.  Sadly, after a supremely muddy woodstock 50 mile in them, one of the "eyelets" where the quicklace system pulls through began to tear which was followed by fraying in the quicklace kevler.  Suffice to say, these shoes are about done.  I have since duct taped them to me feet on days that I really want a mud specific shoe, which certainly works.   *****

Torn quicklace

Well over 1000 miles on this pair

OPSF 50 Mile Race Report (Nov 6th 2010)

A race report I sent out to a group of friends that I figured I would post here since it gets into the racing and fueling I believe make for a successful outing.

Ive had a heck of a trail running fall (2010), starting at the end of August I ran my first 50 mile race in Manistee national forest in Michigan, followed two weeks later by a 50k (31 miles) race on the Potowatami, followed 3 weeks later with another 50k race in Chattanooga Tennessee.   When this was all said in done I realized I had a month to put in some really solid training before I was signed up to run another 50 miler.  With the cooler temps I was really putting in high mileage and happy with my training.

So last Friday I loaded up the Toe-riffica (my pacifica) with my sleeping bag, 3 diff pairs of running shoes, 3 jugs of water, my headlamp, hydration pack and about 25 gu's.  The park was in southern Indiana on the border with Kentucky, some tiny town known as Spencer, in.  After driving 6 hours I was glad to find the park.  I laid out my sleeping bag in the back of my car watched a couple episodes of 30 rock on my laptop and passed out.

Woke up at 5am to eat breakfast, it was cold, like 24 degrees cold.  I like to have 2 hours to digest before the race starts.  -  Breakfast was a banana with peanut butter, a couple bites of a baked potato and a 20 oz pepsi.  breakfast of champions. 


The race:  Owen Putnam State Forest 50 mile was a loop race.  Runners start out running something called a powerline loop which was essentially bushwacking up a big hill for 2.5 miles, then running back down.  After the powerline loop runners begin a 13.4 mile loop on horse trails through the state park.  The hills were steep and rocky, very hard to run up or down because of the technicality.  That means you gotta go fast when its flat and do ur best to get up and down the hills.  Run this loop 3x and then go back and do the powerline again (ouch).

The 50 mile started at 7am and it was still very dark.  Luckily I had expected this and was wearing my petzl tikka 2 plus headlamp that my girlfriend bought me for my birthday.  It worked great I am happy to say.  As soon as the race started I saw 3 or 4 guys take off, I decided to let them go and settled in to chat with some people.  We worked together to stay on the trail and navigate the brush while we were doing the powerline loop, friendly conversation ensued and I learned that I was running with some experienced ultrarunners!

As we finished up the powerline loop I decided to start popping gels.  Early in the race I do 2-3 gels per hour about 200-300 cal/hour.  I was a little worried because my hands were so cold I could barely move my fingers and the skin on my arms was getting numb.  To warm up i decided to run a little harder so I left the guys I was running with and decided to make an attempt to move up in the standings.  Its really important early in these long runs to keep the calories coming early on so I kept eating gu's every 30 minutes. 

After finishing the first 18 miles in about 3 hours and 15 minutes, I had moved up to 4th place, so when i started the 2nd 13 mile loop i wanted to keep the pace up, however I was starting to smell ketones in my breath, meaning I was running low on blood glucose (bonking).  When I came to the next aid station I ate 2 gels at once and chugged two cups of HEED (gatoraide like stuff) and some more pepsi.  I tried to get running again and almost barfed, even worse, my vision was getting hazy...  It was like there was a fog over everything.  I took this as a sign to rest considering i was closing in on 4 hours of running and wasnt half way done yet.  When I need to rest i walk for 2 minutes.  Its usually enough time to digest.  To clear up my vision I decided I had become hyponatremic because I had been drinking mostly water and no salts.  I carry salt pills for this exact reason and took one.  I had to continue this intervention everytime my vision went hazy but it seemed to work.

The rest of the second loop went very well and I passed another person ahead of me to move into 3rd.  As I finished up the 2nd loop I saw the race leaders starting their 3rd loop and decided that I would change shoes and socks and then do my best to catch up.  BAAD idea.  I changed out my MT101 racing flats for a pair of Salamon Speedcross 2 shoes which are heavily cushioned but dont have a rock plate.  No rock plate meant my feet were shredded during that third loop.  There was one section in particular that was about a mile of rocky trail covered literally covered in rocks that you would find on train tracks.  That was the most miserable I was during the entire race.

Coming in to the last aid station of the 3rd loop I noticed one of the volunteers was eating McDonalds.  Never in my life, no matter how much I have had to drink, have I ever wanted french fries so badly.  He offered me some, and i grabbed a few and headed off into the woods.  Finally done with the loops I came back to the race start and realized I was going to have to run the powerline loop again.  At this point (45 miles 8 hours and 15 minutes) I had lost the ability to run fast and was forced into a strange shuffle clomp run.  I pulled out the magic potion.  Mountain Dew.  chugged half a bottle and tore off down the gravel road.  About a mile out i realized I had no idea where I was going.  When we ran this section in the morning it was so dark that nothing looked familiar.  I turned around completely demoralized thinking I would have to head back to the race start and get directions.  Just then the Race Directors wife drove by in a pick up, I flagged her down and asked if I was headed the right direction.  YES I was almost to the trail head.  However I had lost my mtn dew high and was forced back into my shuffle clomp as I started the long climb up the powerline trail.  Just then the race leader, Scott Breeden, came down the hill, I estimated 30-40 min ahead of me.  He warned me that there was a dog loose ahead.  Shit, last thing I needed was to try to run away from a dog.

Turns out it was a German Shepard and really liked to run and bark.  At first I tried to run but I was no match.  As soon as I started to walk the dog calmed down a lot.  I picked up a big rock just in case.  After it stopped chasing me i focused again on the task ahead and picked my way up the powerline.  There is one point where you have to climb up a 20 foot embankment into a briar patch.  I remember it sucked when i was fresh, now pretty tired i grabbed a stick and helped propel myself up the cliff.  At this point I didnt even care about the briars and just let them stab me.  I knew it was all downhill to the finish.  Again I started my strange shuffle and forced down another gel.  The rest of the race just kinda floated by, I knew i was going to finish and was sure i had 3rd locked in.  As soon as I crossed the line the race director came over and congratulated me, handed me some brownies and said there was beer and fried chicken in the race tent.  Chilled by the fire for an hour or two eating and drinking.  

Mtn. Dew high is wearing off...

All in all a great race.  Finished up 3rd overall, final time of 9 hours and 18 minutes.  A time i was thrilled with given the difficultly of the trails.  Some of the other runners who I had beat were very experienced guys who had been doing ultras for years.  All in all my fueling strategy worked great, and liked the pop for breakfast and at the end. 

Maximize Sugar Absorption

Seeing as this is my first entry I am going to begin with a blog that I wrote for the American Society for Nutrition.

I am an endurance junky.  I love endurance sports, particularly running, but also have done my share of long distance biking and swimming. 

One of the most interesting facets of this type of sport is that it heavily involves nutrition and metabolism before, during and after running.  Indeed, I have learned a good deal from my mistakes involving fluid intake, fuel choices, and electrolyte replacement during races and after races; I hope to cover many of these topics in future blogs.  Perhaps the best way to introduce the nutritional considerations that occur during these types of activities is to use my own experience. 


Last weekend a friend (Jason) and I went on a 6 hour (5:22 running time) 31 mile "fun" run on the Potawatomi Trail in Pickney, Michigan.  Check it out sometime.  Its brutal.  My HR monitor reported 3500 calories burned, any exercise requiring beyond 3000 calories and done at a reasonable pace requires additional carbohydrates due to limited glycogen stores (1).    During training runs I aim to consume 200 calories/hour to sustain my running, but at race pace I try to take in upwards of 300 calories/hour.

    My preferred source of fuel during long runs are gel packets which in my opinion offer the advantage of allowing easy tracking of energy intake to avoid the dreaded bonk (exhaustion) and have been shown to be as effective as sports drink when used properly (2).  Sports nutrition companies have formulated these products very specifically, yet include simple instructions that allow these products to be used with little to no knowledge of the nutritional paradigms behind them.  Carbohydrate gel products often include the simple instruction, “consume 1-2 packets for every hour of exercise,” but offer little to no explanation as to why you should use this amount.  They typically contain 100-120 calories, mostly in the form of carbohydrate (20-25 grams carbohydrate) and some contain fats and amino acids.

During this run I consumed 5 clif shots, 1 hammer gel, one pack of clif blocks, 1/2 pack of powerbar chews, 1 bottle of Succeed! Ultra and one bottle of Succeed Amino, 3 Scaps, and about 120 oz of water.  These fuels are mostly maltodextrin, a glucose polymer that is readily digested during strenuous exercise (3); however they also contain some fructose.  I hadn't fully understood the purpose of including fructose in these gel packets, however, recent literature suggests concept of combining multiple sugars in carbohydrate gels or drinks may be beneficial for performance (4).  It is estimated that the maximal glucose absorption rate in the gut is between .8-1.7 grams/min (4), mainly through sodium-dependent glucose cotransporters (SGLT1) (5) while intake exceeding 3 grams/min can lead to gastric distress (3).  Fructose on the other hand, is absorbed mainly via GLUT-5 facilitative transporters, resulting in minimal competition with glucose for absorption (6). Thus, it is thought that maximal exogenous carbohydrate absorption can be achieved by utilizing a combination of glucose and fructose in solution.

These studies have several ramifications for runners.  Most importantly, they indicate that by incorporating fructose into fuel choices during events that demand exogenous carbohydrate consumption may allow the runner to increase the number of calories consumed compared to maltodextrin alone.  These studies also report that the use of a combination of glucose and fructose results in reduced gastric distress (1, 4).  For many people participating in endurance events the goal is to simply finish the event, and often this is dependent on the ability of the athlete to continue to consume fuel.  While there are many variables that contribute to the gastric distress, this research gives insight into a way to both increase fuel intake and maintain a happy gastrointestinal tract.

Works Cited

1.    Jeukendrup AE, Moseley L, Mainwaring GI, Samuels S, Perry S, Mann CH. Exogenous carbohydrate oxidation during ultraendurance exercise. J Appl Physiol. 2006 Apr;100:1134-41.

2.    Pfeiffer B, Stellingwerff T, Zaltas E, Jeukendrup AE. CHO oxidation from a CHO gel compared with a drink during exercise. Med Sci Sports Exerc.  Nov;42:2038-45.

3.    Jeukendrup AE, Jentjens R. Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, guidelines and directions for future research. Sports Med. 2000 Jun;29:407-24.

4.    O'Brien WJ, Rowlands DS. Fructose-maltodextrin ratio in a carbohydrate-electrolyte solution differentially affects exogenous carbohydrate oxidation rate, gut comfort, and performance. Am J Physiol Gastrointest Liver Physiol.  Jan;300:G181-9.

5.    Ferraris RP, Diamond J. Regulation of intestinal sugar transport. Physiol Rev. 1997 Jan;77:257-302.

6.    Shi X, Schedl HP, Summers RM, Lambert GP, Chang RT, Xia T, Gisolfi CV. Fructose transport mechanisms in humans. Gastroenterology. 1997 Oct;113:1171-9.