27 May 2014

Nutrition, carbohydrates and mountain ultramarathon running

Summer finally came to Sweden with temperatures in the high 70’s F (25°C) the past week. As there were some heavy afternoon rains last week in between the sunshine it became unusually green and flowery at once and it has been a treat to run even through the city on my way to work with the blossoming Chestnut trees along the river through Uppsala. I also had a good last week with regards to both volume, as I passed 100 km (60 miles), and speed as I had two good hill repeat sessions.

Chestnut trees in blossom along Fyrisån in Uppsala

I long to race now, but I have decided to focus all my training this year on Petite Trotte à Léon (PTL) in August. Not only has the training for PTL gone well, but I and Otto are also good in our planning and preparations also for the logistics of this long race. One thing we still have to plan further is nutrition. In PTL, which is over 300 km and 28,000 D+ vertical meter and consequently will take well over 100 hours, there are only five aid stations/life bases; at Champex after 56 km, at Bourg St Pierre after 100 km, at Morgex after 170 km, at Col du Petit Saint Bernard after 236 km and Col du Joly after 270 km. No aid is allowed in between these stations, but you are allowed to make use of the local infrastructure of refuges and villages to buy your own food and fluid. Planning a good nutrition strategy will be key to finishing this race and it will differ a lot from “normal” mountain ultramarathon races were you can rely on the aid stations to a great extent. Also, the more technically demanding terrain and the strenuous climbs will make the pace much slower than in a normal ultramarathon and thus the energy demands both in terms of total energy expenditure and rate of energy expenditure will be different. Not surprisingly, there is not much written that can guide our planning specifically, but some guidance can be found in the surprisingly vast amount of literature existing about nutrition for ultramarathon running and I will in this post describe some of the recent findings and recommendations in this area.

The first question I asked was how important the gastrointestinal (GI) function is for finishing an ultramarathon race? That it is important for marathon races and other endurance activities have been known anecdotally for a very long time and Bill Rogers once said that “More marathons are won or lost in the porta-toilets than at the dinner table”. My own personal experience is that it is really important, the closest I have come to a do not finish (DNF) in a race was actually due to severe GI problems with vomiting, perhaps due to inexperience with the sport drink they served at the aid stations, and I was lucky the cut-off times were really generous as I walked most of the later parts of the race. I do not think I now ever in the future will be able to even smell Perpetuem from Hammer Nutrition without becoming nauseated. I am not alone in having had this experience and a study found that 90% of ultramarathon runners feel that nutrition has an influence on overall race performance (Kruseman et al “Nutrient intake and performance during a mountain ultramarathon: an observational study” Eur J Appl Physiol 2005; 94: 151-157).

Looking at the realincidence of GI problems at ultramarathon races it is indeed staggeringly high.   Nausea, vomiting, abdominal cramping and diarrhea have been reported in 37-89% of runners participating in 67-161 km long races (Baska et al “Gastrointestinal bleeding during an ultramarathon” Dig Dis Sci 1990; 35: 276-279; Rehrer et al “Physiological changes and gastro-intestinal symptoms as a result of ultra-endurance running” Eur J Appl Physiol 1992; 64: 1-8; Glace et al “Food and fluid intake and disturbances in gastrointestinal and mental function during an ultramarathon” Int J Sport Nutr Exerc Metab 2002; 12: 414-427; Hoffman & Fogard “Factors related to successful completion of a 161-km ultramarathon” Int J Sports Physiol Perform 2011; 6:25-37; Stuempfle et al “Association of gastrointestinal distress in ultramarathoners with race diet” Int J Sport Nutr Exerc Metab 2013; 23: 103-109; Costa et al “Compromised energy and macronutrient Intake of ultra-endurance runners during a multi-stage ultra-marathon conducted in a hot ambient environment”  Int J Sport Sci 2013; 3: 51-62). In a study of the 100 mile (161 km) Western States Endurance Run (WSER), Hoffman and colleagues found GI problems to be the most common reason given for not finishing the race (23%) and the second most common problem impacting race performance among finishers (37%) (Hoffman & Fogard “Factors related to successful completion of a 161-km ultramarathon” Int J Sports Physiol Perform 2011; 6:25-37). That the GI distress can be really severe is evidenced by the several reports of blood in the stool (feces) following endurance running probably due to mucosal erosions and ischemic colitis causing epithelial surface changes in the lower GI tract (reviewed in Prado de Oliveira et al “Gastrointestinal complaints during exercise: Prevalence, etiology, and nutritional recommendations” Sports Med 2014; 44: S79-S85). There might be a number of causes of the GI problems after ultramarathon running including effects on the gut function (splanchnic hypoperfusion, decreased gut motility, decreased absorption and gut permeability), mechanical causes, nutritional causes and adverse effects of non-steroid anti-inflammatory drugs (NSAIDs) often used by athletes. A good recent review of the possible causes was recently published by Prado de Oliveira and colleagues (Prado de Oliveira et al “Gastrointestinal complaints during exercise: Prevalence, etiology, and nutritional recommendations” Sports Med 2014; 44: S79-S85). It is important to mention that nausea, vomiting and GI problems also might be caused by more serious medical conditions like altitude illness (AMS), exercise-associated hyponatremia (EAH) and heat illness.

The next question I asked was if it would be possible to reduce the incidence of GI distress by following a good nutritional strategy? And how should that strategy look like? From fellow runners I have heard opinions as diverse as “in order to avoid GI distress you should only eat fat and nuts during an ultramarathon” and “only carbohydrate gels, water and salt tablets should be taken during a race”. The truth is, as always, completely individual and the one thing all scientific articles in the area seem to agree on recommending is that there is a need for the individual runner to find what works for her or him through empirical testing during training and racing. That said, it is clear that there are some general recommendations to be made based on nutritional studies in ultramarathons (for reviews see Peters “Nutritional aspects in ultra-endurance exercise” Curr Opin Clin Nutr Metab Care 2003; 4: 427-434; Getzin et al “Nutrition update for ultraendurance athlete” Curr Sport Med Rep 2011; 10: 330-337; Knechtle “Nutrition in ultra-endurance racing – aspects of energy balance, fluid balance and exercise-associate hyponatremia” Med Sport 2013; 17: 200-210; Jeukendrup “A step towards personalized sports nutrition: carbohydrate intake during exercise” Sport Med 2014; 44: S25-S33).

Firstly, ultramarathon running almost invariable will induce an energy deficit as it will be difficult to replenish the consumed calories through nutrition. The total energy expenditure during a 100-mile mountain ultramarathon trail race appears to be in the range of 13,000 to 16,000 kcal (Davies & Thompson “Estimated aerobic performance and energy cost of severe exercise of 24 h duration” Ergonomics 1979; 22: 1249-1255; Fallon et al Nutritional and fluid intake in a 100-km ultramarathon. Int J Sport Nutr 1998; 8: 24–35; Cuddy et al “Total energy expenditure, body water turnover, hydration status, and blood composition during the Western States 100” Med Sci Sport Exercise 2009; 41: S336; Dumke et al “Indirect alorimetry during ultradistance running: A case report” J Sport Sci Med 2006; 5: 692-698). There is thus a theoretical need for an exogenous energy intake of 500-800 kcal per hour and as it for most persons only possible to ingest between 200 to 300 kcal/h a massive energy deficit is unavoidable. There are some indications that ultrarunners might increase the ability to take up calories (Kreider “Physiological considerations of ultraendurance performance” Int J Sport Nutr Exerc Metab 1991; 1: 3-27), but no good studies really prove this. It appears thus very important to achieve as high energy intake as possible in order to avoid going completely “empty” and experiencing fatigue and nausea due to hypoglycemia, in particular at a higher running pace. Undernutrition might furthermore contribute severely to mood deterioration during prolonged endurance activities. Also for multiple stage ultramarathons over several days it appears difficult to avoid a negative energy deficit (Clark et al “Nutritional strategies of mountain marathon competitors – an observational study” Int J Sport Nutr Exerc Metab 2005; 15: 160-172; Costa et al “Compromised energy and macronutrient intake of ultra-endurance runners during a multi-stage ultra-marathon conducted in a hot ambient environment” Int J Sport Sci 2013; 3: 51-62; Costa et al “Perturbed energy balance and hydration status in ultra-endurance runners during a 24 h ultra-marathon” Br J Nutr. 2014; 13:1-10.).

Secondly, there appears to be consensus that the majority of the energy during an ultramarathon race should come from carbohydrates. Even though the exercise intensity during an ultramarathon in general is lower than 70% VO2max and most of the fuel utilization is from utilization of stored fat and free fatty acids, there is evidence that exogenous carbohydrates clearly is beneficial as a fast energy source for the muscles to enhance the use of stored glycogen (Jeukendrup et al “Exogenous carbohydrate oxidation during ultraendurance exercise” J Appl Physiol (1985). 2006; 100:1134-41).  However, a small recent study in 15 runners of the 100-mile race Javelina Jundred show that a race diet with higher percentage of fat at a higher fat intake rate gave some protection against GI distress, so clearly not all energy should likely come from carbohydrates (Stuempfle et al “Association of gastrointestinal distress in ultramarathoners with race diet” Int J Sport Nutr Exerc Metab 2013; 23: 103-109). With regards to carbohydrates, most studies show comparable rates of GI distress in runners with high and low carbohydrate percent intake and rate (Glace et al “Food and fluid intake and disturbances in gastrointestinal and mental function during an ultramarathon” Int J Sport Nutr Exerc Metab 2002; 12: 414-427; Pfeiffer et al “The effect of carbohydrate gels on gastrointestinal tolerance during a 16-km run” J Sport Nutr Exerc Metab 2009; 19: 485-503; Stuempfle et al “Association of gastrointestinal distress in ultramarathoners with race diet” Int J Sport Nutr Exerc Metab 2013; 23: 103-109; Mahon et al “Macronutrient consumption prior to, and during, a mountain marathon” Am J Sport Sci 2014; 2: 5-12). The recommendations with regards to the rate of carbohydrate needed during has recently been revised upwards as data indicate that intakes up to 90 g/h might be beneficial, see figure below (International Olympic Committee “IOC consensus statement on Sports Nutrition 2010” J Sport Sci 2011; 29: S3-S4; Jeukendrup “A step towards personalized sports nutrition: carbohydrate intake during exercise” Sport Med 2014; 44: S25-S33). In order to achieve intestinal absorption of this high rate of carbohydrates multiple transportable carbohydrates (i.e. a mixture between glucose and fructose) should be ingested (reviewed in Jeukendrup 2014). There appears to be a dose-response in many studies, in particular during endurance cycling and triathlon events, between high carbohydrate intake and performance, but there are of course no good large controlled studies performed in ultramarathon running. Interestingly, in experiments of running bouts of 2.5 – 3 hour intake of carbohydrates have been shown to reduce the exercise induced inflammatory reaction, in particular rise of the IL-6 and IL-1ra, in plasma (Nehlsen-Cannarella et al “Carbohydrate and the cytokine response to 2.5 h of running” J Appl Physiol 1997; 82: 1662-1667; Nieman et al “Carbohydrate ingestion influences skeletal muscle cytokine mRNA and plasma cytokine levels after a 3-h run” J Appl Physiol 2003; 94: 1917-1925; Miles et al “Carbohydrate influences plasma interleukin-6 but not C-reactive protein or creatine kinase following a 32-km mountain trail race” Int J Sport Nutr Exerc Metab 2006; 16: 36-46).
         


Carbohydrate intake recommendations (From Jeukendrup 2014)
 
There are neither any good studies showing particular performance benefits of certain gels, sport drinks and bars containing various mixes of multiple transportable carbohydrates and other nutrients. It is actually quite scary to see some of the claims of sport drink and gel manufacturers with regards to the efficacy of their products. Compared to the standards for pharmaceutical drugs all studies in this area appear to be small studies of very low quality lacking controls, blinding, quite often employing wrong statistical methods and use of poor surrogate endpoints and many studies even lack a primary endpoint and are only descriptive (Henegan et al “Forty years of sports performance research and little insight gained” BMJ 2012; 345:e4797; Thompson et al “How valid is the European Food Safety Authority’s assessment of sports drinks? BMJ 2012; 345: e4753).  Henegan and colleagues state as a conclusion in their survey of the evidence behind (or actually lack thereof) sports drinks that “people should develop their own strategies for carbohydrate intake largely by trial and error”. General consensus appear however to not recommend gels and sport drinks with too concentrated carbohydrate contents and osmolalities over 500 mOsm/L as these appear to be associated with higher GI distress and to balance the intake of carbohydrate gels and drinks with intake of other fluids. I think it also important to stress completely personal features like taste and texture preference of the gel and sport drinks (I know a lot of ultrarunners who have Perpeteum as their favorite race drink while I cannot even smell it without being nauseated as mentioned above). I have found two good overviews of various energy gels at IRunFar (http://www.irunfar.com/2008/12/energy-gel-comparison.html) and Fellrnr (http://fellrnr.com/wiki/Comparison_of_Energy_Gels); they have been helpful for me and appear to still be quite accurate despite being a couple of years old.

Thirdly, there are a number of interesting nutritional strategies were there appear to be growing evidence for benefical effects for shorter running exercises, but were there still is no good data in ultramarathon running. There is much talk about the train low, race high concept with regards to energy and carbohydrates (Hawley & Burke “Carbohydrate availability and training adaptation: effects on cell metabolism” Exerc Sport Sci Rev. 2010; 38: 152-60). I adapt this quite often myself not eating any lunch and have noticed an improvement in running in a low energy state over the past year, but have no study in ultramarathon performance to back up any claims of benefit with this. Another controversial issue is whether to employ carbohydrate loading, in particular with low glycemic index carbohydrates and/or modified starches, or a high fat diet immediately pre-race for an ultramarathon. Again, there are no controlled studies of this in ultramarathon running, although there are small studies suggesting positive effects of both carbohydrate loading and high fat diets for shorter endurance activities (Ormsbee et al “Pre-exercise nutrition: the role of macronutrients, modified starches and supplements on metabolism and endurance performance” Nutrients 2014; 6: 1782-1808). Personally I have always performed best with a short 1-2 day carbohydrate loading regimen before an ultramarathon where I use in particular low glycemic index carbohydrates to fill my stores of glycogen – I know that the scientific rationale for this is almost completely lacking for a race lasting several days, but why not at least start with a completely full tank? Carbohydrate mouth rinse have been shown to be beneficial in shorter races (for reviews see de Ataide e Silva et al “Can carbohydrate mouth rinse improve performance during exercise? A systematic review” Nutrients 2013; 6: 1-10; Jeukendrup “Oral carbohydrate rinse: placebo or beneficial?” Curr Sports Med Rep. 2013; 12: 222-7), but for longer ultramarathons I would be really cautious until it has been shown to at least not be unsafe. Another controversial issue is the ingestion of caffeine and other ergogenic substances in ultramarathons. I will come back to this and discuss this specifically in a later blog post, but personally I noticed the benefit of caffeine in its full extent during TDG last year and it will certainly be an integral part of the strategy for PTL this year. In planning the strategy for such a long race I have also glanced a little on nutritional recommendations for adventure racing as it is so extreme and might not be applicable to “normal” 100-mile mountain ultramarathons (Ranchordas  “Nutrition for adventure racing” Sports Med. 2012; 42: 915-27; Enqvist et al “Energy turnover during 24 hours and 6 days of adventure racing” J Sports Sci 2010; 28: 947-55). The advice common to all ultramarathons over 6-hours appear will anyway be: “Get as much energy into the body as possible without inducing too much GI distress”.

After posting this I got a tip that during Petite Trotte à Léon (PTL) we need to try Léon's blueberry pie in Champex. I already look forward to this; I love blueberry pie, blueberries are indeed beneficial (see my previous blog post), and if we are lucky we will meet the person behind the race, see the video below at http://www.dailymotion.com/video/xt41b0_2012-ultratrailtv-leon-lovey_sport:

 

2012 ULTRATRAILTV - LEON LOVEY by UltraTrailMontBlanc

16 May 2014

Exercise-associated collapse in ultramarathon runners

When starting to write this post, on Friday May 16, it is the warmest day of the year in the UK, where I am currently traveling. I hear that the summer temperatures have finally arrived back home in Sweden as well today and I certainly look forward to not having to run with gloves and a winter hat any longer. I am usually not bothered by warm and hot conditions when running, on the contrary I recorded for instance my personal best half-marathon time on an exceptionally hot day. One common misunderstanding is that heat and dehydration is what causes athletes to collapse at the finish line. I recently read some articles on this subject and was surprised this collapse often is a benign condition named exercise-associated collapse (EAC) that actually has been shown to not be caused in most cases by either heat or dehydration.  In this post I will discuss what is really causing this, often quite scary, “downed runner” phenomenon and how common it is in ultramarathon running. I am also asking the question how to distinguish between non-serious benign causes of collapse and life-threatening sinister conditions requiring immediate medical treatment?

The broad definition of exercise associated collapse is often described as any athlete who is unable to stand or walk unaided during or at the completion of an athletic event. This broad condition should be distinguished from the more narrow definition of benign EAC that is “Collapse in conscious athletes who are unable to stand or walk unaided as a result of light headedness, faintness and dizziness or syncope causing a collapse that occurs after completion of an exertional
event or stopping exercise” (Roberts  “Exercise-associated collapse care matrix in the marathon” Sports Med 2007; 37: 431–3). This distinction is quite interesting as it appears that more sinister and severe cases of EAC often occur during a race, but benign EAC tend to happen in close association with the finish line (St Clair Gibson et al “Crawling to the finish line: Why do endurance runners collapse” Sports Med 2013; 43: 413-424). The reason for this is unclear, but it has been postulated by St Clair Gibson and colleagues that benign EAC might be associated with the pacing strategy and psychological and mental factors, see also for instance my previous blog post about pacing in MUT running. This type of benign EAC quite often follow a dramatic movement pattern in what St Clair Gibson and colleagues name The Foster dynamic collapse positions, see figure below, when the runner is struggling to reach the finish line in what looks almost like a primordial automated survival mode.

The Foster Dynamic Collapse Positions associated with EAC. From St Claire Gibson et al 2013

There are no good studies of how frequent both benign and severe EAC is in endurance events in general, but some estimate is from between 1/5000 to 1/20,000 in persons participating in athletic events so it is not that uncommon. There are even figures claiming EAC affects so many as 1-4% of ultramarathon runners (Hoffman et al “Medical services at ultra-endurance foot races in remote environments: Medical issues and consensus guidelines” Sports Med 2014; Epub ahead of print). The incidence of the most serious cause of EAC, sudden- death is less well known in ultramarathons, but appear to be around 1/50,000-1/259,000 in marathons (Maron et al “Risk for sudden cardiac death associated with marathon running” J Am Coll Cardiol 1996; 28: 428-431 59; Kim et al. “Cardiac arrest during long-distance running races” New Engl J Med. 2012; 366: 130–40; Webner et al. Sudden cardiac arrest and death in United States marathons. Med Sci Sports Exerc 2012; 44: 1843–5). I would think the risk for sudden cardiac death to be lower in ultramarathon runners who often are better trained and prepared than many novice marathon runners, but good studies are still lacking here.

Besides sudden death, most often due to cardiac arrest or arrhythmia, other serious causes of EAC include exercise-associated anaphylaxis [EAA] (Povesi Dascola & Caffarelli “Exercise-induced anaphylaxis: A clinical view” Ital J Pediatr. 2012; 38: 43),  exercise-associated hyponatremia [EAH] (Rogers & Hew-Butler “Exercise-associated hyponatremia: overzealous fluid consumption” Wilderness Environ Med 2009; 20: 139-43), hypoglycemia (Holtzhausen &  Noakes “Collapsed ultraendurance athlete: proposed mechanisms and an approach to management” Clin J Sport Med 1997; 7: 292-301), dehydration (Kenefick &  Sawka ” Heat exhaustion and dehydration as causes of marathon collapse” Sports Med. 2007; 37: 378-81), exertional heat stroke (Noakes “A modern classification of the exercise-related heat illnesses” J Sci Med Sport. 2008; 11: 33-9; Casa et al “Exertional heat stroke: new concepts regarding cause and care” Curr Sports Med Rep. 2012; 11: 115-23), hypothermia (Roberts “Heat and cold: what does the environment do to marathon injury?” Sports Med. 2007; 37: 400-3), sickle-cell haemoglobinopathy (Loosemore et al “Sudden exertional death in sickle cell trait” Br J Sports Med 2012; 46: 312-4), rhabdomyolysis (Szczepanik et al “Exertional rhabdomyolysis: identification and evaluation of the athlete at risk for recurrence” Curr Sports Med Rep 2014; 13: 113-9), exercise-induced bronchospasm (Bussotti et al “Respiratory disorders in endurance athletes - how much do they really have to endure?” Open Access J Sports Med. 2014; 5: 47-63) and a number of other rare disorders. Trauma in mountain ultrarunning is also rather common and should definitively be ruled out; see my previous post about this.

Benign EAC is an exclusionary diagnosis when the more serious causes of collapse have been ruled out (Roberts “Exercise associated collapse in endurance events: a classification system” Phys Sportsmed 1989; 17: 49-59; Holtzhausen et al “Clinical and biochemical characteristics of collapsed ultra-marathon runners” Med Sci Sports Exerc 1994; 26: 1095–101; Speedy et al “Exercise-associated collapse: postural hypotension, or something deadlier?” Phys Sportsmed. 2003; 31: 23–9). There are a number of good recent reviews about benign EAC and the treatment for this (Asplund et al “Exercise-associated collapse: an evidence-based review and primer for clinicians” Br J Sports Med. 2011; 45: 1157-62; Anley et al “A comparison of two treatment protocols in the management of exercise-associated postural hypotension: a randomized clinical trial” Br J Sports Med 2011; 45: 1113–8”; Childress et al “Exertional collapse in the runner: evaluation and management in fieldside and office-based settings” Clin Sports Med. 2010 Jul;29(3):459-76; Brennan & O'Connor ”Emergency triage of collapsed endurance athletes: a stepwise approach to on-site treatment” Phys Sportsmed 2005; 33: 28-35; Holtzhausen & Noakes. “Collapsed ultraendurance athlete: proposed mechanisms and an approach to management” Clin J Sport Med  1997; 7: 292–301). As mentioned, benign EAC is often occurring in close proximity to the finish line and is one of the more common reasons for being admitted to the medical tent after a marathon. It can also occur in association with the finish line and there are several Youtube videos available of quite scary episodes of EAC where the runner assume the Foster positions mentioned above.





The causes (etiology) of benign EAC is believed to be postural hypotension with reduced blood flow to the brain due to inadequate venous return necessary to maintain adequate blood pressure associated with a low heart rate and highly a activated symphatic and parasymphatic nervous system. The treatment is cessation of the exercise, when watching the videos below I am always surprised why the runner is not being taken out from the race immediately and helped, and lying the runner down in the supine position on his/her back and raising the legs/pelvis to facilitate blood flow to the brain (the so called Trendelenburg position), skin cooling and offering of moderate oral hydration. If the consciousness is not improved immediately, further evaluation with measurement of vital signs (pulse rate/ blood pressure/ temperature [rectal]/ saturation), heart auscultation, ECG if possible, and laboratory analysis (glucose, sodium, CPK, creatinine in particular). A possible diagnostic and treatment algorithm proposed by Asplund and colleagues is shown below, however, I think any standard emergency protocol that the medical service team at the race is comfortable with can be followed. In the case of benign EAC most runners can be released from the medical tent at the finish line within one hour. There are no good studies of the risk of a repeated benign EAC when having experienced it once, but the risk appears to be low and I am aware of a large number of both elite and amateur runners like myself who have had a scary example of an EAC only once in a long running career. There are speculations that lower-body compression garments might prevent against EAC, but there are no good studies of this.

Treatment algorithm of EAC. From Asplund et al 2011.

I have myself experienced an EAC a couple of years ago, not when I was running but after a tough indoor spinning cycle exercise. It was a real case of syncope as everything suddenly went black and I fell of the bike, luckily after I had clipped out my cycling shoes as it otherwise might have been quite painful (even though it hurt quite much anyway when I regained my conscience lying on the floor). I thought it was due to the heat in the room, but know now that it most likely was caused by postural hypotension when I stopped exercising too abruptly. So, in closing, do not stop immediately at the finish but continue to jog and walk for a while. And pace yourself reasonable.

12 May 2014

Fall weekend – ultramarathon injuries and medical care in remote environments

The past week it has felt like fall in Uppsala with freezing temperatures in the mornings and peak temperatures in the afternoons in the high 40’s (around 10°C). The spring has not completely stalled, however, just slowed down and it is becoming really green after all rains. I do not know if it is the weather, but I have felt quite tired the past week and it has reflected my training were I have fallen back to slower distance training runs.

The reason for the name of this post is however not the fall-like weather. Last Friday lunch I was out for the first real speed training Fartlek of around 15 km (10 miles) for a week. I was running on a rather technical trail along the local lake Mälaren, a wonderful path leading to hidden beaches and a normal spring day you would encounter both walkers and cyclists here, however, due to the pouring train I was running completely alone this day. I also frequently left the normal path, venturing out in the woods quite often to gain more elevation. It was real life quality and as it felt really great and I was really inspired I found myself gradually increasing my speed during my rushes - until I suddenly fell headlong with really strong force. When I lay gasping for my breath, as I had landed mostly on my chest, in a puddle of water I realized I had stepped on one of my shoelaces as an amateur. Luckily, I fell in an uphill section and landed rather softly and did not sustain any serious injuries.  It was however quite an humbling experience and, as my Iphone 5 once again had stopped working due to the cold and rain, I realized I would probably have been lying for quite some time before I was found if I had been severely injured. Certainly not like Aron Lee Ralston, but two take-home lessons from this episode are anyway: 1) always bring a functioning weather resistant mobile; and 2) let someone know where I am going running.
 
Running alone in the rain along the Lake Mälaren
I was also reminded about the risks of traumatic falls during trail running following Transvulcania at Irunfar this weekend and noticing Emelie Forsberg sustaining a rather severe fall requiring hand stitches and surgery. The medical care seemed to have worked excellently, as I think is the case for most races nowadays. I was really impressed by the medical care, even though I myself declined any despite the best interest of at least my feet, at Tor des Geants last year. A guideline for medical care services at ultra-endurance foot races was just published in Sports Medicine (Hoffman et al “Medical services at ultra-endurance foot races in remote environments:  medical issues and consensus guidelines” Sports Med 2014; Epub ahead of print). It is an excellent review of what the medical organization at a mountain ultramarathon might encounter and it sets the minimum standards for what a race organization should provide. The minimum level of medical services that each event should have in place is according to the article a plan for emergency transport of injured or ill participants, pacers, spectators, and event personnel to local hospitals or medical facilities.

Emelie Forsberg having sustained a hand injury at Transvulcania 2014. Picture from Irunfar
 
Most race organizations today, however, are expected to provide more comprehensive level of medical support and care and the article about Hoffman and colleagues discusses some of the legal and organizational ramifications with this. Paradoxically, having medical support at a race might expose the race organization and the medical personnel to litigation as no waiver advising participants of risks and their assumption of those risks absolve from responsibility for gross negligence and the definition of this is most often determined through a litigation process. There is currently a debate ongoing about this in Sweden and the advice from for instance the Swedish Medical Association to all Swedish physicians is actually to not provide health care at an event unless you are willing to assume full legal responsibility as a care giver. This is a major issue and the Swedish Ministry of Health and Social Affairs is therefore actually currently investigating how the laws could be changed to more readily enable physicians and other licensed health care professionals to give care during sports events. Good Samaritian-type legislation is clearly not providing protection for volunteer athletic events in either Sweden or other countries such as the US (Ross et al “Action in the event tent! Medical legal issues facing the volunteer event physician” Sports Health 2013; 5. 340-345).

On a smaller personal level for me as a physician this creates some uncertainties and thoughts about what I for instance should bring for the first aid medical kit at Petite Trotte à Léon in the form of equipment and medication. Should I bring epinephrine and other medicines and a laryngeal mask or endotracheal tubes for cardiopulmonary resuscitation? Medicines and equipment for wound stitching? Where is the border between giving care for an acute life threatening condition and to give general medical care? Regardless of the legal ramifications I am probably aiming to bring enough equipment so that I can take care of most acute situations that my teammate Otto and myself can encounter between the aid stations. And, to have a telephone working in rain and cold.  

 

06 May 2014

Tapering in mountain ultramarathon running

The mountain ultramarathon race season is now certainly here, both with big races like the upcoming Transvulcania this weekend, but also with an increasing number of local races when more and more of the winter snow is disappearing. I have still not decided if, and when, to race before this year’s main event for me, Petite Trotte à Léon, in the end of August. One thing that makes me hesitate is the disruption in my training that preparation before and recovery after the race will cause. I could of course just run a race like a longer training run, but that would most likely be too stressful and lead to even longer need for recovery, so some kind of tapering before the race would most likely be needed. I just came across an interesting blog post about tapering written in Swedish by Johan Renström. It is written from a personal perspective and not focused on ultramarathon running specifically, but it inspired me to look at what is known about tapering for endurance running. First, there are different definitions of what tapering is, but the scientific definition appears to be “a progressive nonlinear reduction of the training load during a variable period of time in an attempt to reduce the physiological and psychological stress of daily training and optimize sports performance” (Mujika & Padilla “Scientific basis for precompetition tapering strategies” Med Sci Sport Exerc 2003; 35: 1182-1187).

In his blog post, Renström refers to the probably best quoted study about tapering in recent years which is a metaanalysis of the effects of tapering on athletic performance by Bosquet and colleagues (Bosquet et al “Effects of tapering on performance: A meta-analysis” Med Sci Sports Exerc 2007; 39: 1358-1365). In this metaanalysis 27 out of 182 potential studies of tapering on competitive athletes were included and there was for instance eight studies of swimmers (number of athletes [N] = 249), six studies of cyclists (N = 80) and nine studies on runners (N = 110). The overall results show a maximal, albeit still small to moderate, gain of a tapering intervention of 2-weeks duration where the training volume is exponentially decreased by 41-60%, without any modification of either training intensity or frequency (see Figure below). The mean improvement was 1.96%, clearly of relevance for competitive athletes as such an improvement in for instance Olympic swimming or track and field running is larger than the difference between the gold medalist and fourth place in general.

The effect of tapering (From Bosquet et al 2007)
The strength of this meta-analysis is the amount of data included. However, this is also the weakness as my main critique of the study that it is difficult to draw conclusions regarding tapering for a specific sport based on data from a lot of very different sports. In my teens I competed rather seriously in military pentathlon, a sport containing heavy elements of both swimming and running, and my own personal experience is that tapering for swimming is clearly different than for running. The authors also clearly state this in the paper and discuss the differences between sports, but in the interpretation of the study afterwards the general findings are those that are applied whatever sport. There are clear differences between swimming, running and cycling (see Figure below), and although the numbers are too small to draw conclusions with certainty, it appears that for running the optimal taper duration appear to be 8-14 days and that the optimal decrease in training volume is somewhere between 21-60%.
 
The effect of tapering in different sports (From Bosquet et al 2007)
The studies included are all focused on short running performances and it is unclear whether the results could be applied to longer ultramarathon distances and whether for instance longer tapering would be more beneficial for longer distances. However, results from a large new review from the same authors involving training cessation shows measurable negative effects on muscular performance already after 15 to 28 days (Bosquet et al “Effect of training cessation on muscular performance: A meta-analysis” Scand J Med Sci Sport 2013; 23: 140-149). The data with regards to mid-distance running is somewhat conflicting both with regards to duration as some studies indicate that training can be reduced for as much as 15 weeks without loss of endurance performance (Hickson et al “Reduced training duration effects on aerobic power, endurance, and cardiac growth” J Appl Physiol 1982; 53: 225-229). With regards to volume reduction some studies indicate that low-volume tapering is better than moderate-volume (Shepley et al J “Physiological effects of tapering in highly trained athletes” Appl Physiol 1992; 53: 706-711; Mujika et al “Physiological responses to a 6-day taper in middle-distance runners: influence of training intensity and volume” Med Sci Sports Exerc 2000; 32: 511-517) and that the 21-60% found to be beneficial in Bosquet’s study would be a too small reduction. There are some studies indicating that progressive tapering (either linear or exponential [see figure below]) might be more beneficial than step (Zarkadas et al “Taper increases performance and aerobic power in triathletes” Med Sci Sports Exerc 1994; 26:34-39; Houmard et al “Reduced training maintains performance in distance runners” Int J Sports Med 1990; 11-46-52). This appears to be the case not only for aerobic capacity, but also muscle power (Brännström et al “Effects and mechanisms of tapering in maximizing muscular power” Sport Art 2013; 1: 18-23). A new computer simulation of tapering schemes indicate that increasing the training load by 20 to 30% during the final three days of the taper my even optimize performance so there is clearly a need for more research with regards to this (Thomas et al “Computer simulations assessing the potential performance benefit of a final increase in training during pre-event taper” J Strength Cond Res 2009; 23: 1729-1736).

Different types of tapering (From Mujika et al 2003)

Other limitations of the meta-analysis by Bosquet and colleagues is that in most studies included there were only men so it is unclear whether the results could be applied directly also to women. The physiology and metabolism between men and women has in several studies been shown to be different. The effect of age is also unclear, as is the athletes training status before the taper, whether they were overtrained/overreached or not, jet-lag and pre-competition travel, altitude acclimatization, heat/cold acclimatization, hydration and nutritional status (i.e. carbohydrate loading of glycogen stores) are also possible co-founders.  The physiological and molecular effects of tapering are still unclear, even though there is starting to appear some mechanistic studies in for instance runners (Luden et al ” Myocellular basis for tapering in competitive distance runners” J Appl Physiol  2010; 108: 1501-9).

One very interesting finding in Bosquet’s meta-analysis is that the training load should not be reduced on the expense of training frequency or intensity. Several studies have found that reducing training intensity during tapering is negative and leads to a decrease in performance (reviewed in for instance Mujika et al “Physiological changes associated with the pre-event taper in athletes” Sports Med 2004; 34: 891-927 and Smith “A Framework for understanding the training process leading to elite performance” Sports Med 2003; 33: 1103-1126). It is important to retain a very high intensity of over 80-90% VO2max. One variant of a tapering scheme with volume reduction, but not training intensity is the Magness-Salazar taper, also mentioned in Renström’s blog post. In this scheme, the last week is focused on short fast intervals on hard surfaces. There are no scientific studies of the tapering scheme, but for track and field running it appears winning as it is employed by for instance Mo Farah and Galen Rupp (gold and silver medalist on 10000 meters in the 2012 Olympics in London). It is unclear whether this is relevant for mountain ultramarathon running, however, as such short training and at such high intensity might not be relevant for these distances and this kind of terrain. Personally, I tend to replace some of my volume trainings with short hard Fartlek in technical terrain, it is fun and inspiring for both the legs and the brain and I did this even before the really long Tor des Géants last year.
 
Mo Farah & Galen Rupp in London Olympics
There are almost no studies of multiple peaking during the competitive season. However, there are some recommendations found in recent reviews (Pyne et al “Peaking for optimal performance: research limitations and future directions” J Sports Sci 2009; 27: 195-202; Le Meur et al “Tapering for competition: A review” Sci & Sport 2012; 27: 77-87). They include prioritization of only 2-3 major races each season with prolonged >1 week tapering periods, with at least 2 months of training blocks between these events. For other events only short period (~4-7 days) tapers should be employed and the recovery period also kept short to allow quick restoration of the training load.

A new venue of research appears to be monitoring of the tapering through continuous analysis of the cardiac autonomic function, by following for instance post-exercise heart rate recovery (HRR) or heart rate variability (HRV) and this is possible for most athletes today through pulse watches with heart rate monitoring (reviewed in Buchheit “Monitioring training status with HR measures: do all roads lead to Rome?” Fron Physiol 2014; 5: 1-19). This is potentially very interesting and I look forward to the findings from research in this area in the coming years.

Again, there are no specific taper studies in ultramarathon athletes to my knowledge and I think the general advice to find a method that works for oneself is perhaps the best. Looking at other blog posts about tapering for ultramarathon runners, for instance by Torrence at Irunfar,  Bleakman at Ultra168 and Elson at Centurion Running, they also come to the same general conclusions.

02 May 2014

Should I run straight or in zigzag up steep mountain ascents?

Zigzag path in the Aosta Valley at Tor des Geants
I have written a lot about hill running in the last few posts. However, running up the hills around Uppsala is clearly different from going up a real mountain. I was clearly made aware of this when I read a mail from the race director of Petite Trotte à Léon (PTL) Jean-Claude Marmier earlier in the week. In his mail to all PTL 2014 runners he emphasizes the importance of following the rigourous regulations for safety reasons and also announces some new measures:

“After the Col du Petit Saint Bernard at KM 243, you will have to cross the Col de l’Argueray 2853 meters, a superb passage between France and Italy. This pass was on the 2012 PTL® itinerary. Unfortunately, its crossing had to be cancelled due to particularly unfavorable conditions.  This pass is protected on its north face by a miniscule glacier (free of crevasses) with a slope of 25°. Covered in snow this crossing is not a problem. At the end of the season, it could be sheet ice and become a sure obstacle for the trail-runner. This year, putting the odds in our favor, we have decided to add an anti-slip system to the obligatory equipment which allows safe progression on gentle snow-packed or icy slopes”

The icy slope through a glacier at Col de l'Argueray at 2853 meters
It will certainly be a formidable challenge to cross Col de l’Argueray and it will now be, as Col Malatra was during Tor des Géants, my mantra during the race as I think it might be the last really difficult pass before the finish line (although I think I will have to “eat my own words” [not sure if this is also an English expression – quite frequently used in Swedish] many times during the last 50 kilometers after this pass). I have never run a race in crampons, and neither trained in them either, and the first time will probably be during PTL if there is ice. Nevertheless, I become encouraged watching Anton Krupicka in his latest film “In the High Country”,  where he puts on crampons and effortlessly run up Long’s Peak covered in ice and snow.
 
Anton Krupicka putting on crampons in the film In the High Country 
There appears also be some really light crampons specifically designed for trail running from for instance Hillsound, Snowline and Kahtoola.
 
Crampons on trail running shoes
The light weight of the crampons will most likely not be so important for it enables fast running, I will walk and not run up Col de l’Argueray and its 25° slope, but as it adds more weight to the backpack during this long race. I am not sure of the paths up the pass either, but I expect it not to be a straight line but involving some zigzagging and traversing the slope. When I previously wrote about comparisons between different ultramarathon races the gradient of the slopes along the path was not specifically considered in the equation and an interesting mathematical, physical and physiological problem is at what gradient it becomes more advantageous to run in zigzag rather than straight up the slope.  This critical angle at which this transition should take place is of course, as so much else in mountain ultrarunning and life in general, something subjective and influenced by a number of factors and I do not think one should think so much about it but rather follow the path and when there is a choice feel what is right at that particular moment, much like what Sam Robson so eloquently says in his latest blog post. However, I could anyway not stop thinking about this problem and looked into what was written in the literature about it. I will only discuss going uphill and come back to downhill running in a separate blog post later on.

An often referred study is by Llobera and Sluckin from a couple of years back (Llobera & Sluckin “Zigzagging: theoretical insights on climbing strategies” J Theor Biol 2007; 249: 206-217). In this study they build a semi-quantitative theoretical model of the behavior of humans walking on terrain with relief by minimizing the metabolic energy cost per unit of distance and the structure is according to the authors resembling the Landau Theory of Phase Transitions. They find that hairpin bends (switchbacks) and shortcuts appear as efficient strategies for downhill walkers, and switchbacks are retained also in uphill walking. For weakly inclined slopes, the best strategy is to walk/run directly downhill and uphill, while for sufficiently steep slopes, depending on the terrain, the best strategy would be to transition to a “broken symmetry solution corresponding to the switchback trail patterns typical of rugged environments” i.e to zigzag down- or uphill. The gradient at which this transition should occur in this model is at an angle of 16° (28.7% slope).

In classical studies based on volunteers running on treadmills with various slopes, Margaria and colleagues (Margaria et al “Energy cost of running” J Appl Physiol 1963; 18: 367-370) and Davey and colleagues (Davey et al “Running uphill: an experimental result and its applications” J Opl Res Soc 1994; 45: 25-29 and Davey et al “Speed, gradient and workrate in uphill running” J Operational Res 1995; 46: 43-49) determine the angle to be around 20° (36.4 % slope) when it is more efficient to walk or run in zigzag rather than run straight up the hill from an energetic perspective. Data from Minetti and colleagues in their treadmill tests of 10 elite athletes practicing endurance mountain racing rather than normal healthy controls indicate critical gradient for transition of around 15.5° (27.6 % slope) (Minetti et al “Energy cost of walking and running at extreme uphill and downhill slopes” J Appl Physiol 2002; 93: 1039-46).

Antohony Kay at the Department of Mathematical Sciences at Loughborough reviews these studies in greater detail in his paper “Route choice in hilly terrain” which is freely available on the web at http://www.academia.edu/2876712/Route_choice_in_hilly_terrain. Another freely available paper discussing this is Ulrich Leuthäusser’s “About walking uphill: time required, energy consumption and the zigzag transition” where he recalculates the critical gradient according to the formula below and find it to be 13.8° (24.6% slope). Surprisingly it is in his model very robust between 13° - 16° regardless of power (i.e. how fast one is moving uphill). His paper is available at http://sigmadewe.com/fileadmin/user_upload/pdf-Dateien/Bergaufgehen_engl.pdf .

The formula for the critical gradient in Leuthäusser's paper
Quite interestingly, looking at different terrains the paths appear to both go straight up at slopes greater than this, but also in many cases to go in zigzag at slopes lower than this. For safety reasons, and in respect of the nature, I think that in most cases one should anyway follow the path present and not take shortcuts even though it might not be the fastest way up from a race pace perspective. When running (or walking when it comes to most uphill sections) PTL I expect the path to frequently be non-existing and, at least with crampons, the route choice will most likely be straight even though the slope might be higher than mathematical critical gradient of around 15° (26.7%) as outlined above.