29 April 2014

The benefit of running short uphill repeats

It has been summer temperatures in the high 60’s (around 20 degrees Celsius) in Uppsala the past week and it feels a little like the spring just rushed by so I am almost looking forward (or not) to the snow which is expected here on Thursday.

Flower path on the way to the hill
The past week was absolutely great also from a running perspective – I focused on short hill repeats to build both muscle strength, aerobic capacity and to improve my so called energy cost of running. I believe it is really a good training form to improve all three of these factors. I ran a total of five short hill repeat trainings during the week each training lasting between 30-60 minutes with varying number of repeats of 1-2 minutes. My total vertical gain during the week was around 3000 meters (9850 feet), almost ridiculously little considering the D+ of over 28,000 meters (92000 feet), approximately ten times as much, waiting at Petite Trotte à Léon (PTL). However, I think that even short hill repeats are really beneficial. The science is a little bit ambiguous regarding the extent of the benefit, however, but as it really is a fun exercise and something I think directly applicable to the practice of running in mountains. Jill Homer just posted a very inspiring text about the fun of practicing bike riding and I guess I think the practice of running uphill as really fun, despite thepain when being close to or just over the lactate threshold.  

Regarding the evidence for the benefit of hill repeats I just read a great PhD graduate thesis entitled “Strategies to improve running economy in trained distance runners” written earlier this year by Kyle Barnes at Sports Performance Research Institute New Zealand at Auckland University of Technology (freely available at http://hdl.handle.net/10292/7125). In his thesis and an associated publication, Barnes demonstrate that already well-trained athletes can improve their running economy substantially with 2-6% through acute and chronic bouts of movement-specific resistance exercise performed by short duration near-maximal uphill sprints (Barnes et al “Effects of different uphill interval-training programs on running economy and performance” Int J Sports Physiol Perform. 2013; 8:639-47). In the study they let twenty well-trained runners (average 5-km race personal best time of 16.5 ± 1.2 min and average weekly training volume of 95 ± 25 km) perform aerobic and biomechanical test before and after a 6-week training period during which they were assigned to one of five uphill interval training programs (see figure below).

From Barnes et al 2014.
There were no clear optimum for time-trial performance (see figure below), but Barnes and colleagues conclude that runners can assume that any form of high-intensity uphill interval training will benefit 5-km time-trial performance. The results from Barnes are confirmed by recent findings by Ferley and colleagues of well-trained runners undergoing a 6-week treadmill training program, but they also find that normal interval training on flat surface leads to the same improvements (Ferley et al “The effects of incline and level-grade high-intensity interval treadmill training on running economy and muscle power in well-trained distance runners” J Strength Cond Res. 2014; 28:1298-309; and Ferley et al “The effects of uphill vs. level-grade high-intensity interval training on VO2max, Vmax, V(LT), and Tmax in well-trained distance runners” J Strength Cond Res. 2013; 27: 1549-59).

From Barnes et al 2014
There are no similar studies of hill repeats in mountain ultramarathon runners specifically, but I think the results would be even clearer and more directly applicable to the race situation. An interesting study of a runner wearing a portable metabolic unit during the first 64.5 km of Western States Endurance Run 100 not surprisingly reveals higher energy expenditure while running a trail in mountain terrain compared to energy requirements required by this individual when running in nonundulating terrain (Dumke et al “Indirect calorimetry during ultradistance running: A case report” J Sport Sci Med 2006; 5: 692-698). It has been hypothesized in  recent Norvegian study by Losnegard and colleagues that the optimal exercise economy can be achieved in an exercise mode where the athletes are highly skilled and that uphill running, compared to cross-country skiing, is good for this as the technical requirements is lower (Losnegard et al “Exercise economy in skiing and running” Front Physiol 2014; 5: 1-6). I think this is only partly true as in particular during some ultramarathons trails there will be some clear technical challenges that might improve running economy and it is important to practice this specifically – for instance running with poles can be a challenge from a technical standpoint if not tested before. Losnegard’s study was also conducted on a treadmill. Indeed, I have in a previous post discussed the findings by Vernillo and colleagues that runners of Tor des Géants during the race modified their uphill-running patterns for a more economical mechanics and lower energy cost of running uphill specifically (Vernillo et al "Influence of the world's most challenging mountain ultra-marathon on energy cost and running mechanics" Eur J Physiol 2014; 114: 929-939).

In summary, practicing short uphill repeats appear to be beneficial for running mechanics and decreases the energy cost of running, but more studies are needed to investigate if and how much they specifically can improve longer mountain ultramarathon performance.

24 April 2014

Predator attacks, pacers and ultramarathons

I am very happy that there have been some reactions on my post regarding pacers in ultramarathons. I just today got a great reply from Robert which puts the difference between the US and Europe into a better perspective . The reply is definitively worth sharing, not only as a comment to the post, but also here as it deserves better space. I am very grateful for being able to share his thoughts and copy the reply below. He points out that the original purpose with pacers in mountain ultramarathons in the US actually was protection against predators like the North American Cougar, and that such animals are not the same threat in Europe.  This was something not apparently clear to me and I can definitively understand and agree and think that safety of course is paramount in all competitions. I would definitively not like to be stalked alone on the trail by such an animal.

I am not familiar with the predators in the Alps, but here in Sweden and the Nordics we have, besides the Eurasian Lynx mentioned by Robert, and which is quite small and harmless, the Wolverine and Grey Wolf, but both are mostly trying to avoid humans and there are no reported attacks or deaths to my knowledge in recent years. However, in Alaska a young teacher was killed by a flock of wolves while out running alone ac ouple of years ago. More dangerous, in particular during this time of the year when they are waking from the winter hibernation and when the mothers are particularly protective of their cubs, are the Brown Bears. During 1977 to 2012 there were 31 humans injured and 2 killed during bear attacks in Scandinavia (figures found in Veronica Sahlén’s PhD thesis “Encounters between Brown Bears and humans in Scandinavia – contributing factors, bear behavior and management perspectives” from 2013 at Department of Natural Resource Management at Norwegian University of Life Sciences. It is freely available in English in a pdf format at the Scandinavian Brown Bear Research Project webpage). I am uncertain if there were any runners among those attacked by Brown Bears, but I would not think it unlikely.

A Scandinavian Brown Bear. This particular bear is not wild but living at Orsa Bear Park
I can also think pacers would be beneficial for safety of other reasons such as prevention of navigation mistakes in strenuous long ultramarathon races and avoidance of other objective dangers in technical mountain terrain. However, in those cases it might be better to organize the race as a team event, like what is done for Petite Trotte à Léon (PTL), one of the UTMB races. It is a new and very stimulating experience for me to plan for this year’s  race together with Otto Elmgart and it will be great to run this long and hard race together in particular as there are some glacier crossings and technical passages where I would have hesitated to be alone even in a non-sleep deprived and exhausted state.

The inspiration to my statement that pacer’s should not be allowed in “normal” ultramarathons was when I saw that there were pacers allowed in the Swedish 100 mile race Täby Extreme Challenge (TEC 100). There are certainly no predators or other dangerous animals present at this location just outside Stockholm, the capital of Sweden, and as the race consists of 16 laps of 10 kilometers and is rather flat without any technical passages there are no safety reasons for allowing pacers. Indeed, reading the race report from the winner of TEC 100 this year it is clear how helpful pacing was in particular during the last laps. I am concerned that having pacers like this is a trend not only in the US as Robert mentions, but also in Europe.

“Hi Peter,

I agree with your sentiment with respect to utilization of pacers in ultramarathons. Here in the US there are real concerns about safety in some ultramarathons (mostly the mountainous, remotes ones in the Western US) as it concerns predators. Predators were exterminated in the Alps sometime after about 1800 and have only recently (1990's) been reintroduced. Even so, there have never been nor are there now any large cats (cougars) in the Alps. The Slovenian Alps have successfully reintroduced the Eurasian Lynx but this cat is not considered a real threat to human life as is the North American Cougar (Puma concolor couguar). There were 5 confirmed human killings in the decade 2001-2010, including a cross country skier just outside Canmore AB (site of the 1988 Olympic Cross country Skiing events). There were dozens of non-death injury reports as well and probably thousands of sightings. So we take interaction with this animal very seriously. Most attacks upon humans are of solo individuals as is the preference of such a predator. Numbers really matter when dealing with such a large dangerous animal, even just two will have a much better chance of scaring the thing off than a lone individual. Read this harrowing account by Joe Grant when he was stalked for 5 miles on a solo 100 miler in Washington state a couple of years ago:

There are many ultramarathons in the US where such safety issues are either non-existent or so minimal as to not be considered a risk, yet pacers are encouraged by race directors. I find this unfortunate but seemingly cultural for US ultramarathons. Karl Meltzer is one US-based runner who eschews pacers and is quite vocal about it- he has had nary a dent in the practice. I think that pacers should be allowed when there is a documented safety concern, otherwise they should not be allowed or at least have different classes where the real winner is the one who do not use a pacer. Interestingly, USA Track and Field do not allow pacers (or music) in their ultramarathon championship events.”

22 April 2014

Pain and ultramarathon running – Exercise induced hypoalgesia and pain perception following acute or chronic running

The sun and warmth came with force to Uppsala this past Easter weekend and it has been temperatures in the mid 60s Fahrenheit (around 18 degrees Celsius) in the shadows. The snow has almost finally disappeared from the local ski piste Sunnerstabacken and I went for this year’s first real hill repeat training. Usually, I try to do these exercises with my trekking poles, as I will use the poles during mountain races where I think they are really beneficial I consider it appropriate to also train with them, but this time I for some reason left them at home. I do not know if it was due to this I experienced quite severe pain in my quadriceps already during the training or if it simply is my lack of serious hill repeat training during the winter. I am now experiencing a rather pleasant delayed onset muscle soreness (DOMS) as well.

Some patches of snow still lingering

As it was the muscle pain rather than my lungs or heart that put the limit on my hill repeats I wondered about how ultramarathon runners perceive pain. Is the sensitivity to pain different among ultramarathon runners in general? What about pain sensitivity during and immediately following races and training? Looking into the literature for studies I found not so many on pain (also called nociception) and ultramarathon running, but more on endurance training and running in general. There is plenty of evidence that exercise not only in itself often is rather painful, but that it also induces a transient decreased sensitivity to pain, so called exercise-induced hypoalgesia (EIH), lasting about half an hour after most types of exercise (reviewed in for instance Dannecker & Koltyn “Pain during and within hours after exercise in healthy adults” Sports Med 2014; Epub ahead of print; Janal “Pain sensitivity, exercise and stoicism” J R Soc Med 1996; 89:376-381). There was recently a meta-analysis published on the subject by Naugle and colleagues (Naugle et al “A meta-analytic review of the hypoalgesic effects of exercise” J Pain 2012; 13: 1139–1150). In this meta-analysis, a total of 25 studies,  consisting of a total of 437 healthy volunteers,  using a repeated measures design to examine the effect of acute isometric, aerobic, or dynamic resistance exercise on pain threshold and pain intensity measures were included were included. The results suggest that all three types of exercise reduce perception of experimentally induced pain in healthy participants, with effects ranging from small to large depending on pain induction method and exercise protocol. The mean effect size for aerobic exercise was moderate, while the mean effect sizes for isometric exercise and dynamic resistance exercise were large.

The mechanism behind EIH is at least partly mediated by endogenous central opioid mechanisms, as some of the effects are reversed by treatment with the opioid agonist naloxone as shown in several studies (see for instance Janal et al “Pain sensitivity, mood and plasma endocrine levels in man following long-distance running: effects of naloxone” Pain 1984; 19: 13-25). A very interesting study by Scheef and colleagues used functional magnetic resonance imaging (fMRI) to study which areas of the brain that were activated and to what degree during a painful thermal heat-pain challenge before and after 2 hours of running or walking in 20 trained athletes. Pain activation levels were elevated after walking, but decreased or unchanged after running, in particular in the periaqueductal grey (PAG) pathway in the brain (Scheef et al “An fMRI study on the acute effects of exercise on pain processing in trained athletes” Pain 2012; 153: 1702-1704). Running, but not walking, also reproducibly elevated beta-endorphin levels in plasma indicating an involvement of the opioidergic system. The interesting with the study by Scheef and colleagues was also that the pain sensitivity was tested after a rather strenuous running bout of two hours, in contrast to most studies which employ much shorter tests for aerobic “endurance” exercise. It is still unclear what the intensity threshold is for aerobic exercise-induced hypoalgesia, although it appears that there might be a dose-response and more vigorous exercise will produce larger EIH (Naugule et al “Intensity thresholds  for aerobic exercise-induced hypoalgesia” Med Sci Sports Exerc 2014; 46: 817-825). This is a controversial issue and some studies indicate that even non-painful exercise can induce EIH and that conditioned pain modulation (CPM) therefore is not the primary mechanism behind EIH (Ellingson et al “Does exercise induce hypoalgesia through condition pain modulation?” Psychophysiology 2014; 51: 267-276).

While it since long has been clear that the pain sensitivity is decreased through EIH immediately following exercise it is more unclear whether pain perception in general is different in athletes compared to normal healthy controls. A recent meta-analysis included fifteen studies, with a total of 899 subjects, where pain perception was compared between athletes and normally active controls following experimentally induced pain (Tesarz et al “Pain perception in athletes compared to normally active controls: a systematic review with meta-analysis” Pain 2012; 153: 1253-1262). The main outcome measures were pain tolerance and pain threshold. The meta-analysis showed that athletes possess higher pain tolerance compared to the controls (Hedges’g =0.87; 95%CI 0.53 -1.21; p < 0.00001), whereas the available data on pain threshold were less uniform.  Looking specifically at running, Scheef and colleagues followed up their study of acute pain modulation with fMRI discussed below with a study of 39 healthy non-trained male volunteers that were assigned to either six-months running exercise or non-exercise controls. 28 individuals completed the study (15 exercise and 13 controls) (Boecker et al “Antinociceptive effects of physical exercise: Inducations for chronic pain modulation in endurance runners” Klin Neurophysiol 2014; 45: P96). Pain related activation was studied with fMRI before and after the 6 months intervention together with pain perception thresholds and physiological variables. The analysis was done with no exercise at least 48 hours prior to the MRI. There were pain related activity in right insula and left mesial/lateral premotor cortex and post-hoc within group analysis revealed relative decreases of insular activity in the exercise group and relative increases of premotor activity in the control group. The findings indicate that there are chronic adaptive changes in the brain function regarding pain processing associated with regular exercise training. These functional brain imaging findings are supported by previous studies of marathon runners showing chronic reduction of pain perception, for instance by Johnson and colleagues (Johnson et al “Marathon runner’s reaction to potassium iontophoretic experimental pain: pain tolerance, pain threshold, coping and self-efficacy” Eur J Pain 2012; 16: 767-774).

But what about ultramarathon runners? First, an interesting study from Martin D. Hoffman’s laboratory of 21 runners finishing the 100-mile mountain trail race Western States Endurance Run (WSER) in 2005, compared with 11 control subjects, looked at acute pressure pain perception after an ultramarathon (Hoffman et al “Pain perception after running a 100-mile ultramarathon” Arch Phys Med Rehab 2007; 88: 1042- 1048). Surprisingly, only the fastest runners in showed a mean reduction in pain ratings after the race (-15±20 mm on a 100-mm visual analogue scale) (p < 0.05), whereas there was no change for the slower runners or controls. The authors speculate that it is possible that an extreme bout of exercise of this nature might “exhaust” the systems responsible for EIH in all but the most well-trained runners, or that these systems were not activated as the slower runners were unable to maintain a high enough exercise intensity during the later stages of the race. From personal experience, not being one of the fastest runners, I clearly believe more in the exhaustion theory.

Secondly, Freund and colleagues looked at cold pressure (CP) pain tolerance in 11 runners completing the 4478 km (2789 mile) long TransEurope FootRace 2009 (TEFR09) and compared them with 11 age, sex and ethnicity matched controls without marathon experience during the past 5 years (Freund et al “Ultra-marathon runners are different: Investigations into pain tolerance and personality traits of participants of the TransEurope FootRace 2009” Pain Practice 2013; 13: 524-532). They also performed the 240 item trait and character inventory (TCI) as well as the general self-efficacy (GSE) test. TEFR09 participants had a highly significant greater cold pain tolerance in the CP test than controls (p < 0.00002). There were no differences in the GSE test, but the TEFR09 participants appared less cooperative and reward dependent, but more spiritually transcendent, than the controls in the TCI test. The authors conclude that low pain perception may predispose an individual to become an ultramarathon runner, however, it remains unclear whether low pain perception is a cause or consequence of continuous extreme running exercise.

From Freund 2013. Time course of mean pain intensity ratings during immersion of left hand in ice water. The x-axis shows the time of immersion, the y-axis the pain rating (NRS from 0 - 10). Error bars denot the SD. Asterixes are placed over measurements with significant differences among the groups.
From Freund 2013. Comparison of personality traits between TEFR09 participants and controls using the TCI test and correlation with cold pressor (CP) pain scores  

In summary, ultramarathon running training and racing is clearly associated with pain and it is therefore not surprising that most studies of runners show both acute and chronic decreased sensitivity to pain. This has been found also in other endurance trained athletes, for instance triathletes (Geva et al “Enhanced pain modulation among triathletes: A possible explanation for their exceptional capabilities” Pain 2013; 154: 2317-2323). I think that if you cannot endure, and even in some way thrive on, pain you will not continue run ultramarathons and the first preliminary studies of pain in long endurance running indicate that the positive effects of running, like Runner’s High, might be complemented by enhanced direct pain suppressive mechanisms. I am concerned that the widespread use of non-steroid anti-inflammatory drugs (NSAIDs) in runners, see for instance the widely debated recent study published by Küster and colleagues in British Medical Journal (Kürster et al “Consumption of analgesics before a marathon and the incidence of cardiovascular, gastrointestinal and renal problems: a cohort study” BMJ Open 2013; 3: e002090) might be a dangerous shortcut to replacing these endogenous mechanisms of pain regulation. Not surprisingly, use of NSAIDs was higher among finishers (60.5%) than non-finishers (46.4%) of the 2009 WSER and Vermont 100 Endurance Race (p =0.006) (Hoffman & Fogard “Factors related to successful completion of a 161-km ultramarathon” Int J Sport Physiol Perform 2011; 6: 25-37). I do not think stronger analgesics like some NSAIDs, even though still allowed, has any place in ultramarathon races. Ultramarathon running is really as much about pain management as about lung capacity and muscle strength and endurance.       

16 April 2014

Is it possible to compare mountain ultramarathons? Calculations of the equivalent flat distance as a function of the elevation gain and comparisons of past course record times and speeds

This past weekend the largest Swedish 100 mile trail race, Täby Extreme Challenge (TEC) 100, was held just outside Stockholm. I followed the live race reports on the net and it was thrilling to see the competition fold out between Andreas Falk,   Elov Olsson and Johan Steene. The winner Andreas finished with a great time of 13 hours 34 minutes 31seconds. Still, it was more than one hour slower than Jonas Buud’s really great course record of 12:32 from 2010. Looking at this race record, giving a record speed of 12.9 km/h I started to think about if it would be possible to compare this with record times and speeds on mountain ultramarathons with a higher positive altitude difference (D+). I have previously in a blog post compared a number of mountain ultramarathons with regards to D+/km and noted that Barkley Marathons with a D+/km of 112 really stands out. Among the more famous 100 mile mountain ultramarathon races, most have a D+/km of between 55 to 65, with the exception of Western States Endurance Run (WSER) and Leadville 100, which both have a D+/km or around 30. TEC100 has an even more modest D+/km of 11.3.

Looking in the literature for ways to compare mountain trails with varying climbing distances I came across two different ways to adjust for the climbs and to calculate the equivalent flat distance of mountainous trails with varying elevation profiles. The first method (Method A in figures below) I found is described in Saugy’s paper entitled “Alterations of Neuromuscular Function after the World’s Most Challenging Mountain Ultra-Marathon” comparing Tor des Géants (TDG) with UTMB published in PLoS ONE 2103; 8: e65596. They used the formula flat-equivalent distance = distance (km)+  positive elevation change (meters)/100 and this yields a value of 570 km for the full TDG course and 264 km for UTMB. I have not found the reference for this formula and whether it has been validated or used before.

The second method (Method B in figures below) I found was the so called Naismith's rule, invented by the Scottish mountaineer William W. Naismith already in 1892. According to this rule 3 miles (=15,840 feet) of distance is equivalent in time terms to 2000 feet of climb. In other words, 1 meter of ascent is equivalent to 7.92 (=15840/2000) meters of horizontal distance so time would be a linear function of ascent and distance.  Obviously, Naismith’s rule has been widely used for long time and has been proven useful for walking in particular in hilly terrain with moderate slopes and not too technical terrain. A recent publication tested whether if it would be applicable in shorter fell running competitions and found a good correlation between time and flat equivalent distance using the correction (see figure below) (Scarf “Route choice in mountain navigation, Naismith’s rule, and the equivalence of distance and climb” Journal of Sports Sciences 2007; 25: 719 – 726).
From Scarf 2007
However, in Scarfs study there were only distances up until 80 kilometers included and for the longer races the correlation seemed less good. Another weakness was that the gradients of the races were not compared and that the difficulties with not only uphill, but also downhill, running at steep slopes were not considered. In Naismith’s rule running downhill is the same as running on level ground, something which is clearly not the case in most mountain environments. A third problem is the varying ground terrain and the technicality of the trails. The model has consequently been challenged and in an elegant paper entitled “Pace and critical gradient for hill runners: An analysis of race records” by Kay published in Journal of Quantitative Analysis in Sports. 2012; 8: 1559-0410 (Online) clearly shows that for steeper gradients the Naismith’s rule is clearly not applicable. Based on data from 82 uphill and 14 downhill races he proposes a quartic model where pace can be predicted based on gradient (see figure below). However, again, there are no longer races included in Kay’s analysis either.
From Kay 2012. Pace versus gradient

I have looked at some of the more popular and well-known mountain ultramarathon trail races over 100 miles in order to see whether the method found in Saugy’s paper (Method A) or Naismith’s rule (Method B) can be applied also in longer distances. Not surprisingly, the course record times of 100 mile races varied quite extensively from just under 15 hours to over 25 hours (see table below).

The variation in course records appeared to be at least partly a function of the amount of elevation gain (D+) and both methods to adjust for this appeared actually quite good (see figure below where blue denotes original distance, red distance adjusted to method A and green distance adjusted to method B [Naismith’s rule]).

Just looking at the original record speed as a function of the elevation gain (D+) shows surprisingly good correlation among the races around 100 miles (again, blue original speed, red speed adjusted by method A and green speed adjusted to method B [Naismith's rule]).

There are not many races even longer than 100 miles, but adding Tor des Géants (TDG) to the calculations appear to make the methods less predictable, but still quite good  (in the figures below the same color coding applies to WSER, UTMB, Hardrock100 and TDG). I have not added Barkley Marathons to any of the figures as that race with its extreme course profile and conditions really is an outlier.  
Comparison of WSER, UTMB, Hardrock100 & TDG

Comparison of WSER, UTMB, Hardrock100 & TDG
In summary, when comparing mountain ultramarathons positive elevation gain (D+) appears to be a very important factor in order to determine course record times and speeds. I have done some preliminary calculations of two methods to determine the equivalent flat distance of some of the well-known races and found that both methods are quite good albeit there is certainly room for improvement taking into account for instance average slope of climbs, technical passages and ground conditions, the average altitude over sea level etc. Furthermore, the course record time might not reflect how non-elite runners will perform and how the adjustment method would work for them. Nevertheless, regardless I think that this exercise shows the obvious that if you are planning to run a mountain ultramarathon it is very important to collect climbing distance.  

09 April 2014

Running on snow and sand – the importance of the ground surface for training and racing

It is snowing again today in Uppsala and it took an unusually long time to run to work, not only due to the wet and cold northerly winds blowing in my face, but also due to the slippery ground surface. If this had been November I would have been thrilled by the snowfall, but in April it is only depressing as the snow will anyway not linger long. It clearly hampered my run today and made me think about how much more difficult it would be to run on snow than on asphalt and gravel roads for instance. I looked for literature on the subject, but could not find any studies on the subject. It appears that you should not run on snow, but rather ski, something humans apparently has done since at least 2000 BC (Formenti et al “Human locomotion on snow: determinants of economy and speed of skiing across the ages” Proc R Soc B 2005; 272: 1561-1569).

How I feel about the first snow of the season. Picture from the Whatisultra webpage (http://whatisultra.tumblr.com)

How I feel about snow in the middle of April. Picture from the Whatisultra webpage (http://whatisultra.tumblr.com)  

If there is no data on running on snow there is plenty of data on running and training on sand (“beach running”). A good recent review on the subject is Binnie et al “Sand training: a review of current research and practical applications” J Sports Sci 2014; 32: 8-15. The energy cost of running and walking on sand is clearly higher, approximately 1.5 times higher, than running or walking on grass or firm surfaces (see for instance Zamparo et al “The energy cost of walking or running on sand” Eur J Appl Physiol Occup Physiol. 1992; 65:183-7; Lejeune et al “Mechanics and energetics of human locomotion on sand” J Exp Biol. 1998; 201: 2071-80; Pinnington &  Dawson “The energy cost of running on grass compared to soft dry beach sand” J Sci Med Sport. 2001; 4: 416-30; Pinnington et al “Kinematic and electromyography analysis of submaximal differences running on a firm surface compared with soft, dry sand” Eur J Appl Physiol. 2005; 94: 242-53; and Davies & Mackinnon “The energetics of walking on sand and grass at various speeds” Ergonomics. 2006; 49: 651-60 ). The higher energy cost when running on sand might be due to reduced recovery of elastic energy through decreased efficiency of positive work done by the muscles and tendons and higher mechanical work done (for instance through greater hip and knee range of motion compared with firm surface running). Compared to running on harder surfaces sand will give rise to lower impact forces and this can limit muscle damage and muscle soreness and running on sand is therefore often recommended in rehabilitation training. There exists also plenty of very interesting data on the effects of running on uneven ground and I will discuss this in a later blog post. Both uneven ground and plenty of sand is now currently facing the runners of the 29th edition of Marathon des Sables (MdS) now going on in Sahara. It is now in stage 4 and a good coverage after each stage is posted by Ian Corless at Talk Ultra Podcast 

Running in sand dunes at MdS 2014. Picture from http://iancorless.org


08 April 2014

Should pacers be allowed in ultramarathons? On pacing and the benefit of the anonymous second runner

I grew up running middle distance track and field and shorter cross-country races. Although competing for a club, it was clearly not a team sport as you were completely alone against your competitors and against your personal record times out on the race track. It was great camaraderie though and I very much enjoyed that we all in the club challenged each other’s to improve and do better and we became great friends in the process. I therefore felt at home when starting with ultra- and trailrunning – great camaraderie around the races, but when out on the track I was alone and it was my own physical and mental fortitude that made a difference how I would perform. I have previously written a blog post about my viewpoint on whether to DNF a raceor not and I think one of the major challenges with running an ultramarathon is that you are alone in the fight to endure and not to listen to the voice in your head that says that you should take the easy way out and drop-out at the next checkpoint. I also think one major challenge is to keep up the pace when being alone during a long race, it is so easy to slow down for just a short while, perhaps when you have a difficult period, and thereby really lose much time. When discussing this with some American friends I was quite surprised that almost all mountain ultramarathons in the US allow pacers (also called “pacemakers”, “pace-setters”, “rabbits”), taking away much of these challenges and thereby also taking away the experience received when completing the race alone. I also think it will be difficult to compare racers with each other as having a good pacer really could influence your race time. Furthermore, some runners appears to be really dependent on pacers for even completing ultramarathons. I therefore do not think pacers should be allowed in ultramarathon competitions in order to make them fairer.

Description of a runner's reaction when the pacing crew is not turning up at the aid station. From the American website Whatisultra (http://whatisultra.tumblr.com)  
Do I have support for the hypothesis that pacers are beneficial for running an ultramarathon and influence race time and experience? The answer is no, there are no good studies of pacers in running longer ultramarathon distances to my knowledge.

I could only find a small study of eleven non-elite male athletes running five 5 km time trials either alone (trial 1 and 5) or in the presence of a second runner running behind, beside or next to the runner (Bath et al “The effect of a second runner on pacing strategy and RPE during a running time trial” Int J Sport Physiol Perform 2012; 7: 26-32). The drawback with this study, besides the short running distance, was that the runners did not know that the second runner was a pacemaker. Still surprisingly, there were no changes in pacing strategy (where the running speed declined from the 1st to the 4th kilometer), performance times, heart rate or rate of perceived exertion (RPE) when a second runner was present. These results are partly in contrast to what I would expect, for instance as rhythmical movement appears to influence running (see my recent blog post on the effects of rhythm and music on ultramarathon running). After the trials, however, 9/11 runners perceived it to be easier to complete the 5 km trial with another runner in comparison with running alone indicating at least a social function of running together. It would of course be interesting to do the study with real pacing, involving support and encouragement to push the runner to perform better. In general, emotions appear to play a role in pacing in particular during longer endurance events (reviewed in for instance Baron et al “The role of emotions on pacing strategies and performance in middle and long duration sport events” Br J Sports Med. 2011; 45: 511-7).

Reading the popular literature and blogs about pacers in particular in ultramarathon events it is clear that emotional support is a major part of their role. It appears to be an art to be a good pacer and to select a good pacer is of importance according to several posts and articles, for instance by Theresa Daus-Weber, Ian Torrence, Jason Robillard and Carilyn Johnson. Sadly, the pacer is seldom recognized and I am embarrassed that I when writing this blog post for instance did not remember the name of Scott Jurek’s long-time pacer despite having read his book “Eat and Run” quite recently. His name is Dusty Olson by the way and an interview with him inOutsideonline is quite telling with regards to how it must feel to be “the second runner” in the shadow of the real runner. Some of the descriptions in the book clearly show Dusty’s importance in both avoiding DNF and in the maintenance of speed.

For competitive racers, it is the maintenance of a high constant speed during the later stages of the race that appears to be the most winning pacing strategy. Two recent studies of a large number of competitors in the last year’s world cross country championships clearly indicate that best runners had a more even pace in relation to the rest of the finishers (Esteve-Lanao et al “Running World Cross Country Championships: A Unique Model for Pacing Study” Int J Sports Physiol Perform 2014 [Epub ahead of print]) and used a strategy of running close to the front from an early stage, but did not separate themselves from other top finishers until halfway with the eventual medal positions decided even closer to the finish (Hanley “Senior men's pacing profiles at the IAAF World Cross Country Championships” J Sports Sci. 2014; 32:1060-5). Following ultramarathon races it appears very similar to most top finisher’s strategy and it would be interesting to see how important pacers are in maintaining this even high pace.

A very interesting recent article by Marty Hoffman of the pacing of the winners during 1985 to 2013 of the most famous trail ultramarathon, the 100 mile (161 km) long Western States Endurance Run(WSER), indeed show that the winners had a lower mean coefficient of variation (CV) of 12% compared with the other top-five finishers (14-15%) (p < 0.01) (Hoffman “Pacing by winners of a 161-km mountain ultramarathon” In J Sport Physiol Perform 2014 [Epub ahead of print]). CV in speed was clearly related (r = 0.80, p = 0.006) to finish time for the fastest ten finish times at the WSER. The CV appeared to be influenced by the maximum ambient temperature and also calendar year as the winning finishing times have decreased over time to the current phenomenal record of 14 hours 46 minutes and 44 seconds set by Timothy Olson in 2012. In summary, reducing speed fluctuations appear to be a winning concept in both shorter cross-country races and in longer ultramarathons such as WSER. It would be very interesting to see how influential pacers are in particular for the ultramarathon competitions and whether the variation in speed is higher in a race without pacers, such as for instance UTMB.

Mean segmental speeds for top-five WSER finishers for different race segments. Lead runners are represented by dashed lines, first finishers by thich solid lines and second through fifth place finishers by thinner solid lines. From Hoffman 2014 in Int J Sport Physiol Perform

Relationship of coefficinent of variation (CV) in speed with finish time for the ten fastes finish times at WSER. From Hoffman 2014 in Int J Sport Physiol Perform
So far, however, I have to my knowledge no scientific support that pacers influence performance in ultramarathon competitions. My viewpoint that they should not be allowed is therefore only personal. It is interesting that pacers appears to be mostly allowed in American races and not European. This could reflect either a higher degree of competitiveness, if you think that pacing is beneficial. It could also reflect another degree of risk awareness perhaps from a different cultural and legal framework in the society in general. That pacers are needed in order to minimize risks for the runners is an argument that is often brought forward by (American) race organizers. I agree fully that I think a pacer would reduce the risks due to fatigue and exhaustion, perhaps not so much for elite runners of 100 mile races, but for slower runners like myself. When finishing Tor des Géants last year I would clearly have benefited by having a pacer during the last part of the race, when I literally fell asleep running on the small mountain single track. The borderline is difficult, however, and I think that if the risks become too high that rather than allowing pacers you should make it into a team event like La Petite Trotte à Léon which I will run in a Swedish team later this year. All longer endurance adventure races are for the same reasons team events. If pacers continue to be used in “normal” mountain ultramarathons I think we will see the same development as in endurance cycle races with teams supporting lead competitors. It is not wrong, but clearly a different type of sport and far from yourself racing against the mountain track. The recent rise of fastest known time (FKT) attempts might be another sign of wishes to return mountain ultramarathon running to its basic form.

07 April 2014

The motivational board

Monday morning and a cold persistent rain poured down on my run to work. It can certainly be hard to motivate oneself on days like these. However, just a quick glance beside my office desk at my “motivational board”, which I have had now since over one year for both TDG in 2013 and PTL in 2014, makes me full of spirit again. Note the pictures of Hannibal crossing the Alps - this year's Petite Trotte à Léon (PTL) will pass in the area of some of the candidate crossings and I have as so many others before me become fascinated by this historical adventure and the enigma of which way he and his army really took over the Alps.

04 April 2014

Runner’s High – Does it exist? Is ultramarathon running addictive?

It is Friday, the sun is back and it is one of those clear crisp cold spring days here in Uppsala. Tomorrow the trail race season in Sweden will really start with Ursvik Ultra, a 75 km (47 mile) night race starting in the middle of the night between Saturday and Sunday. It is the 15th time the race is held and it has grown tremendously in the past years and there are over 100 registered runner’s for this year - there is really a running boom of shorter trail and ultra trail races like this in Sweden. I elaborated for a long time whether I should run Ursvik Ultra, I really feel strong now, but decided to do like last year and focus all my training on the year’s overreaching goal and not be distracted by races early in the season, however tempting it may be. Last year my goal was Tor des Géants in the beginning of September and this year it will be La PetiteTrotte à Léon (PTL) in the end of August.

Feeling the urge to run and race, and realizing that I share these feelings with an increasingly large number of people in the “running boom”, made me think about the similarities between running and addiction and whether you can become dependent on running. I have previously mentioned in a blog post that if I used the normal diagnostic criteria for a substance use disorder according to DSM-5 and changed the word substance to running I clearly scored high (fulfilling 9/11 criteria) in having a “Running Use Disorder” and thus be dependent on running. I will in a later blog post review the various scales, besides DSM-5 which actually does not contain a term for exercise dependence or exercise use disorder, that have been used in the literature to define “Exercise Addiction”. The term “exercise addiction” appears to be well established and there have been a number of scientific articles published on the area (reviewed in for instance Landolfi “Exercise addiction” Sports Med. 2013; 43: 111-9; Berczik et al “Exercise Addiction: Symptoms, diagnosis, epidemiology, and etiology” Subst Use Misuse. 2012; 47: 403-17; Kerr et al “Exercise Dependence” 2007 (Book) Routledge, New York, NY, US).

It is tempting to speculate that there might be similar neuropsychological and neuropathophysiological mechanisms in dependence to running or substances. A very interesting recent study tested the hypothesis that exercise is associated with lower frequency (incidence and prevalence) of psychiatric disorders (Dakwar et al “Exercise and mental illness: results from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC)” J Clin Psychiatry 2012; 73: 960-6). Data were collected from 2001 to 2005 as part of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) and the sample consisted of 23,505 nondisabled US adults aged between 18 and 65 years. Contrary to the hypothesis,  individuals who engaged in vigorous exercise were significantly more likely than were nonexercisers to be diagnosed with a current psychiatric disorder (adjusted odds ratio [AOR] = 1.22, 95% CI, 1.12-1.34 for the nationally recommended amount vs no exercise), significantly less likely to attain remission from a psychiatric disorder between waves (AOR = 0.77, 95% CI, 0.65-0.91), and significantly more likely to relapse or be newly diagnosed with a psychiatric disorder between waves (AOR = 1.15, 95% CI, 1.02-1.30). Alcohol dependence and bipolar II disorder were the disorders most strongly associated with exercise. The authors speculate that this surprising finding may be due to reward-related factors that influence both exercise engagement and the expression of certain psychiatric disorders, but that further studies are needed. Similar conclusions can be drawn from a review by

Interestingly, the findings by Dakwar and others give support to the hypothesis that exercise can serve as a reward that is particularly reinforced in individuals who have vulnerabilities in reward-related neurocircuitry and that treatment thus can be used as a treatment for substance use disorders. The benefit of exercise as a treatment for psychiatric disorders and substance use disorders have recently been reviewed by Zschucke and colleagues (Zschucke  et al “Exercise and Physical Activity in the Therapy of Substance Use Disorders” Scientific World Journal 2012; 2012: 901741; Zschucke  et al “Exercise and Physical Activity in Mental Disorders: Clinical and Experimental Evidence” J Prev Med Public Health.  2013; 46: S12–S21). Another mechanism besides the reward-related might be effects on underlying depression in both disorders. That exercise in general, and specifically running, has anti-depressive effects in both mice and men has been shown in many studies (reviewed in for instance Helmich et al “Neurobiological alterations induced by exercise and their impact on depressive disorders” Clin Pract Epidemiol Ment Health. 2010; 30; 6:115-25; “Running is rewarding and antidepressive” Physiol Behav. 2007; 92: 136-40).

I think one common mechanism in both cases might be the benefical psycophysical effects exercise and in particular indurance training can induce, such as stress reduction (Rosch “Exercise and stress reduction”. Compr Ther. 1985; 11: 10—15), anxiolysis (Morgan “ Affective beneficence of vigorous physical activity” Med Sci Sports Exerc. 1985; 17: 94—100), mood elevation (Janal et al “Pain sensitivity, mood and plasma endocrine levels in man following long-distance running: effects of naloxone” Pain. 1984; 19: 13—25) and reduced pain perception (Janal et al “Pain sensitivity, mood and plasma endocrine levels in man following long-distance running: effects of naloxone” Pain. 1984; 19: 13—25). There are numerous reports in both popular and scientific press regarding a state of euphoria associated with in particular running, often referred to as “Runner’s High” (Wagemaker & Goldstein “The runner’s high”  J Sports Med Phys Fitness 1980; 20: 227—229; Partin 1983 “Runner’s ‘‘high’’” JAMA. 1983; 249: 21). A number of studies have attributed runner’s high to changes in central opioidergic transmission caused by increased levels of endorphin’s in the brain, the so called “endorphin hypothesis”. This hypothesis has however been questioned as it was based mainly on elevated levels of endorphins in circulating peripheral blood and not the brain (Dietrich & McDaniel “Endocannabinoids and exercise” Br J Sports Med. 2004; 38: 536—541). In addition there are other neurotransmitters implicated in Runner’s High, such as endocannabinoids (Raichlen et al “Exercise-induced endocannabinoid signaling is modulated by intensity” Eur J Appl Physiol 2013; 113: 869-75).

A seminal study providing support for the existence of “Runner’s High” and that it is at least partly caused by endogenous opioids in the brain was published in 2008 where 10 trained male athletes ran for 2 hours before undergoing positron emission tomography (PET) analysis of opioid receptor occupancy and scoring of euphoria (Boecker et al “The runner's high: opioidergic mechanisms in the human brain” Cereb Cortex 2008; 18: 2523-31). Reductions in opioid receptor availability were identified preferentially in prefrontal and limbic/paralimbic brain structures. The level of euphoria was significantly increased after running and was inversely correlated with opioid binding in prefrontal/orbitofrontal cortices, the anterior cingulate cortex, bilateral insula, parainsular cortex, and temporoparietal regions. That short term running influences brain biochemistry is further corroborated by the findings of brain changes and plasticity after a long term ultrarunning exertion in participants of the 4500 km long Trans Europe Foot Race project, which I previously have posted a blog post about (Perrey & Mandrick “Evidence from neuroimaging to explore brain plasticity in humans during an ultra-endurance burden” BMC Med 2012; 10: 171).
From Boecker et al “The runner's high: opioidergic mechanisms in the human brain” Cereb Cortex 2008; 18: 2523-31

Finally, a very interesting recent study by Raichlen and colleagues tested the hypothesis that it is neurobiological rewards, i.e. runner’s high, that motivate human endurance exercise in general from an evolutionary perspective. They studied endocannabinoid signaling (eCB) in in humans, dogs (another cursorial mammal) and ferrets (a non-cursorial mammal) before and after treadmill exercise to test the hypothesis that neurobiological rewards are linked to high-intensity exercise in cursorial mammals. They show that humans and dogs share significantly increased exercise-induced eCB signaling following high-intensity endurance running. eCB signaling does not significantly increase following low-intensity walking in these taxa, and eCB signaling does not significantly increase in the non-cursorial ferrets following exercise at any intensity. The study thus indicate that inter-specific variation in neurotransmitter signaling may explain differences in locomotor behavior among mammals. The authors speculate that the fact that “running, and endurance exercise in general, remains an enjoyable and psychologically beneficial recreational activity for tens of millions of humans today suggests that we still may respond to a neurobiological trait that evolved early in our lineage”. Time to go out running and get high.

02 April 2014

Music and ultramarathon running – can music enhance running performance? And has the human ability to run created our rhythmical talent and musicality?

The effects of music on exercise

The sun was back today this morning when I ran to work and so were the birds singing in the trees. Influenced by their song I felt stronger and probably ran a little bit too fast. It also made me think about the strong effect I think music can have on athletic performance. However, what is the scientific evidence that music really can improve running performance and in particular ultramarathon endurance? One of my strongest personal memories of how music could affect my mood and perceived rate of exertion when running was when I left Rifugio Sogno di Berdzé on the second evening of Tor des Géants 2013. The race had been going on for approximately 36 hours and I had been running for 117 kilometers and just climbed over 1000 meters from the last life-base in Cogne. Leaving the Rifugio I worried about some pain in my calves and Achilles tendons and I felt quite alone in darkness and cold that surrounded me. In my misery I decided to put on some Italian pop music and suddenly it felt like a surge of power hit me and in a blink I was at the Col Fenetre di Champorche, having actually run up the last part of the climb. It was probably the first time I really discovered the power of music when running.

Looking into the literature I found a vast amount of scientific articles on the effects of music on exercise. That music may have an effect on athletic performance has been studied for over 100 years and the probably first publication on the topic was published already in 1911 (Ayers “The influence of music on speed in the six day bicycle race” Am Phys Educ Rev 1911; 16: 321-325). A good recent comprehensive review of the research in this area is Karageorghis and Priest “Music in the exercise domain: a review and synthesis (Parts I & II)” Int Rev Sport Exercise Psychol 2012; 5: 44-66 and 67-84. The British Association of Sport and Exercise Sciences (BASES) has recently published an expert statement on the use of music in exercise (Karageorghis et al “The BASES Expert Statement on use of music in exercise” J Sports Sci. 2012; 30: 953-6 Also available online at http://www.bases.org.uk/Music-in-Exercise). They determine that research evidence (which mostly is generated by themselves so this is obviously a weakness of the statement) demonstrate that music has consistent and measurable effects on the behaviour and psychological states of exercise participants. When music is selected according to its motivational qualities, the positive impact on performance (e.g. increased endurance) and psychological states (e.g. enhanced affect) are even greater. Their salient recommendations are that music should be:

   Congruent with the socio-cultural background and age group of listeners (i.e., reflect familiarity and preferences).

   Functional for the activity (e.g., rhythm should usually approximate motor patterns involved).

   Selected with the desired effects in mind (e.g., loud, fast, percussive music with accentuated bass frequencies as an arousal-increasing intervention).

   Selected in consultation with participants using some form of objective rating method (e.g., Brunel Music Rating Inventory-2; Karageorghis et al., 2006).

   Characterised by prominent rhythmic qualities and percussion in addition to pleasing melodic and harmonic structures for repetitive aerobic and anaerobic exercise tasks. Harmony refers to sounding multiple notes together, giving music its emotional “colour” (e.g., happy, sad, ruminative).

   Within the tempo band of 125-140 beats per minute for most healthy exercisers engaged in repetitive, aerobic-type activity (slower music is appropriate for warm-up and cool-down).

   Imbued with motivating associations, conditioned either through the media or the personal experiences of the listener.

   Accompanied by lyrics with affirmations of movement (e.g., “run to the beat”) or generic motivating statements (e.g., “the only way is up”).

   Used in ways where safety is not compromised (e.g., exercisers should not use music when running or cycling on the roads). 

Conceptual framework from Terry & Karageorghis "Psychophysical effecs of music in sport and exercise: An update on theory, research and application" in M. Katsikitis (Ed) (2006)

The effects of music on running and walking

To summarize the effects of music specifically on running and walking most studies show beneficial effects. The running experiments have, however, mostly been conducted with healthy volunteers running short distances on a treadmill (see articles below).

·         Baldari et al “Effects of music during exercise in different training status” J Sports Med Phys Fitness. 2010; 50: 281-7.

·         Barwood et al “A motivational music and video intervention improves high-intensity exercise performance” J Sport Sci Med 2009; 8: 435-442

·         Bood et al “ The power of auditory-motor synchronization in sports: Enhancing running performance by coupling cadence with the right beats”. PLoS ONE 2013; 8: e70758.

·         Brownley et al “Effects of music on physiological and affective responses to graded treadmill exercise in trained and untrained runners” Int J Psychophysiol. 1995; 19: 193-201

·         Copeland & Franks “Effects of types and intensities of background music on treadmill endurance” J Sports Med Phys Fitness. 1991; 31:100-3.

·         Crust “Effects of familiar and unfamiliar asynchronous music on treadmill walking endurance” Percept Mot Skills 2004; 99: 361–368.

·         Debarnot & Guillot “When music tempo affects the temporal congruence between physical practice and motor imagery” Acta Psychol 2014; 149C: 40-44 [Epub ahead of print]

·         Edworthy & Waring “The effects of music tempo and loudness level on treadmill exercise” Ergonomics 2006; 49: 1597–1610.

·         Karageorghis et al “Psychophysical and ergogenic effects of synchronous music during treadmill walking” J Sport Exerc  Psychol 2009; 31: 18–36.

·         Lima-Silva et al “Listening to music in the first, but not the last 1.5 km of a 5-km running trial alters pacing strategy and improves performance” Int J Sports Med; 2012; 33: 813–818

·         Savitha et al “The effect of vocal and instrumental music on cardio respiratory variables, energy expenditure and exertion levels during sub maximal treadmill exercise” Indian J Physiol Pharmacol 2013; 57: 159-68

·         Szmedra &  Bacharach “Effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running” Int J Sports Med 1998; 19: 32–37

·         Terry PC et al “Effects of synchronous music on treadmill running among elite triathletes” J Sci Med Sport 2012; 15: 52-7.

There are not many studies of music when not running on a treadmill and I only found a few, again mostly looking at the effects on shorter distances like 400-meters (Simpson & Karageorghis “The effects of synchronous music on 400-m sprint performance” J Sports Sci 2006; 24: 1095–1102) or around in a circle with 15-meter diameter in a sports hall (Leman et al “Activating and relaxing music entrains the speed of beat synchronized walking” PLoS One. 2013; 8: e67932). There was one study investigating the effects of music on mood and emotions during normal running exercise (Lane et al “Effects of music interventions on emotional states and running performance” J Sports Sci Med. 2011; 10: 400-7), and another investigating in 19 healthy runners whether peak locomotion frequency of ~3 Hz during outdoor running is synchronized with different intrinsic and extrinsic frequencies using accelerometer and  electroencephalography measurements (Schneider et al “Exercise, music, and the brain: is there a central pattern generator?” J Sports Sci. 2010; 28: 1337-43).

The effects of music on other exercise forms

Most studies of music as an ergogenic aid to facilitate physical performance has been performed on aerobic exercise and with predetermined music. Above I have mentioned some of the studies with running, but there exists many similar studies of indoor cycling on a trainer. There have also been some studies on strength training recently published and one cross-over study of twenty healthy males performing resistance strength and explosive exercise in the form of bench press and squat jump showed that self-selected music improved in particular the explosive squat jump performance and lowered RPE and improved the mood state (measured with the profile of mood states [POMS] scale) (Biagnini et al. Effects of self-selected music on strength, explosiveness, and mood J Strength Cond Assoc 2012; 26: 1934-1938). These findings are supported by a recent study by Fritz and colleagues of 52 volunteers showing that musical feedback, so called musical agency, during use of exercise machines improved mood (Fritz et al “Musical feedback during exercise machine workout enhances mood” Front Psychol  2013; 4: 921).  A similar study also by Fritz and colleagues was recently published in the prestigious journal PNAS where they also showed clear beneficial effect of musical agency, compared with passive music listening, on rate of perceived exertion (RPE) in 62 participants performing strenuous exercises on fitness machines. For instance, very interestingly, oxygen consumption as acquired with spirometry showed that, although exhibiting no differences in total force under both conditions, the oxygen consumption was lower during musical agency than during passive music listening. It thus rather appears that participants were able to apply a comparable amount of force using less oxygen. An effect with music on oxygen consumption has previously been shown on treadmill running  (Szmedra &  Bacharach “Effect of music on perceived exertion, plasma lactate, norepinephrine and cardiovascular hemodynamics during treadmill running” Int J Sports Med 1998; 19: 32–37).

The effects of music on ultramarathon running

There are no published scientific articles on music on ultramarathon running performance. However, I came around a great PhD dissertation thesis from 2012 entitled “Effects of synchronous music in sport and exercise: a meta-analytic review and field studies of ultra-distance athletes” on the topic by Michelle Louise Curran from University of Southern Queensland in Australia in Professor Peter C Terry’s laboratory. It is freely available at http://eprints.usq.edu.au/23670/ . In the thesis she performed a meta-analysis of 86 published research studies of general effects of music on athletic performance showing, albeit small to moderate, clear statistically significant positive effects of music on performance, feelings, heart rate, oxygen utilization (VO2) and rate of perceived exertion (RPE). In the thesis there is also an interventional study specifically of two ultra distance runners completing a 20 km training session on four occasions listening to synchronous motivational music, synchronous neutral music, an audio book, or no music. Motivational music provided the two runners with significant benefits compared to no music and audio book conditions. In a second interventional study in the thesis the same interventions was studied in nine ultramarathon runners completing ultra-distance races of 6, 24 and 48 hours duration and showed, quite interestingly, superiority of motivational music over other interventions during in particular the 18-24 hour period. In general, that music can influence fatigue is supported by the central governor model advocating the effects of not only biochemical reactions in the muscle, but also the central nervous system in endurance activities (Noakes “Fatigue is a brain-derived emotion that regulates the exercise behavior to ensure the protection of whole body homeostasis” Front Physiol 2012; 3: 1-14).
From Noakes 2012. The central governor hypothesis of fatique

What music to listen to during running?

The BASES recommendation states that synchronous music  (i.e., when an exerciser consciously moves in time with a musical beat) in particular has been shown to provide ergogenic and psychological benefits in repetitive endurance activities. For example, motivational synchronous music used during treadmill walking improved time to voluntary exhaustion by 15% compared to motivationally neutral and control conditions in 30 participants waling on a treadmill (Karageorghis et al “Psychophysical and ergogenic effects of synchronous music during treadmill walking” J Sport Exerc  Psychol 2009; 31: 18–36). BASES also suggest that synchronous music may increase rhythmicity of movement, resulting in an efficiency gain that is associated with lower relative oxygen uptake. However, in the metaanalysis performed in Curran’s thesis there was limited difference in outcome benefits between synchronous and asynchronous music. Other findings indicate that, among young adults, preferred music tempo generally falls within a narrow band (125-140 beats per minute) regardless of exercise intensity (Karageorghis et al “Revisiting the exercise heart rate music tempo preference relationship”  Res Quart Exercise Sport, 2011; 82: 274-284). Contrary to theoretical predictions, the relationship between exercise movement and heart rate and preferred music tempo was found to be nonlinear, characterized by a series of inflections.

A very interesting recent study investigated the relative effects of auditory-motor synchronization and the motivational impact of acoustic stimuli on running performance (Bood et al “The power of auditory-motor synchronization in sports: Enhancing running performance by coupling cadence with the right beats”. PLoS ONE 2013; 8: e70758). In this cross-over study, 19 participants ran to exhaustion on a treadmill in 1) a control condition without acoustic stimuli, 2) a metronome condition with a sequence of beeps matching participants’ cadence (synchronization), and 3) a music condition with synchronous motivational music matched to participants’ cadence (synchronization + motivation). As expected, time to exhaustion was significantly longer with acoustic stimuli than without, but unexpectedly, however, time to exhaustion did not differ between metronome and motivational music conditions, despite differences in motivational quality. Thus, acoustic

stimuli may have enhanced running performance because runners worked harder as a result of motivational aspects (most pronounced with motivational music) and more efficiently as a result of auditory-motor synchronization (most notable with metronome beeps). The authors conclude that the findings imply that running to motivational music with a very prominent and consistent beat matched to the runner’s cadence will likely yield optimal effects because it helps to elevate physiological effort at a high perceived exertion, whereas the consistent and correct cadence induced by auditory-motor synchronization helps to optimize running economy. Similar findings that the motivational qualities of music may be less important than the prominence of its beat and the degree to which participants are able to synchronise their movements to its tempo was also recently found in a study by Terry and colleagues of 11 elite triathletes running on a treadmill (Terry PC et al Effects of synchronous music on treadmill running among elite triathletes J Sci Med Sport 2012; 15: 52-7).

Quite interestingly, some music appear to be activating as it can entrain the speed of beat synchronized walking, supporting the hypothesis that recurrent patterns of fluctuation affecting the binary meter strength of the music may entrain the vigor of the movement (Leman et al “Activating and relaxing music entrains the speed of beat synchronized walking” PLoS One. 2013; 8: e67932). This may be attributed to an attentional shift, a subliminal audio-motor entrainment mechanism, or an arousal effect, but further research is needed to study this further.

In summary, there is still no clear evidence that one type of music is preferably over another when running. Quite interestingly, looking at the playlists of elite ultrarunners, compiled by Daniel Rowland, it is indeed a great variety of music.

The motivational effects of music versus video on exercise performance

There have recently been some studies looking at the effects of both music and video during exercise. A small cross-over study was performed on six healthy male volunteers by Barwood and colleagues investigating the effect of motivational music plus video intervention on running distance during a 30-minute exercise bout on a treadmill in warm (~26°C) and moist (~50% RH) conditions in the presence of motivational music and video, non-motivational intervention, or control conditions with no intervention (Barwood et al “A motivational music and video intervention improves high-intensity exercise performance” J Sport Sci Med 2009; 8: 435-442). Despite the small number of participants, they found that motivational music and video increased the running distance and led to higher blood lactate concentration, but that the peak rating of perceived exertion (RPE) did not increase (P < 0.05). The motivational ergogenic music used in the experiment rated high on the so called Brunel Music Rating Inventory (BMRI)-2 and -3 by the participants and included a high beat (>120 bmp) and a strong rhythm. In order to “psych up” (arousal regulation), shift attention focus (association to dissociation) and to encourage psychological skills usage (positive mental imagery) videos of influential sporting feats that the participants were likely to have seen in the media previously was also shown. The non-motivational intervention consisted of 30 minutes of public speaking from a recent political trial in the USA.  The study opens up for more research with regards to the relative importance of the music and the video intervention. It becomes little of a theoretical question as when running a mountain ultramarathon I am absolutely convinced that breathtaking scenery and the mountain surroundings in itself is highly motivating.

Has the human ability to run created our rhythmical talent and musicality?

Lastly, when I reviewed the scientific literature for the effects of music on running I came across a set of recent articles forming a very interesting hypothesis that running, or more correctly the bipedal locomotion of humans, has influenced our evolution of rhythmic abilities. It appears rhythmic entrainment (beat-based timing) is specific to humans among primates and not found in for instance macaque monkeys (Merchant & Honing “Are non-human priamtes capable of rhythmic entrainment? Evidence for the gradual audiomotor evolution hypothesis” Front Neurosci  2014; 7: 274). These findings based on new cross-species research generates a challenging view questioning Darwin’s hypothesis that our capacity for musical rhythm reflects basic aspects of brain function broadly shared among animals (Patel “The Evolutionary Biology of Musical Rhythm: Was Darwin Wrong?” PLoS Biol 2014; 12: e1001821). One very interesting hypothesis, formed by the Swedish physician Matz Larsson, is that human locomotion and ventilation generates sounds that needs to be masked by synchronization of locomotion when humans walk and run in groups and that thus bipedal gait and the associated sounds of locomotion influenced the evolution of human rhythmic abilities (Larsson ”Self-generated sounds of locomotion and ventilation and the evolution of human rhythmic abilities” Anim Cogn 2014; 17: 1–14). This is a virgin research area that I think will be very interesting to follow in the coming years. I like the idea very much though and I will when running home today try to listen to not only the birds but also the rhythm and music of my own body when moving.

From Merchant & Honing 2014. Auditory stream in the brains of non-human primates and humans