|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)|
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.