When to Hike and When to Run with Jackson Brill⎮KoopCast Episode 24

what's going on trail and ultra runners welcome to another episode of the KoopCast i hope this podcast finds you well whether you are out on the trails running you're in your car during a commute or you just happen to be getting ready for work or the day in general i appreciate everybody tuning in to this episode on today's podcast we have the young the up-and-coming the incredibly incredibly stylish with his soon-to-be trademark bandana that i am sure is going to hit the paris fashion runways by storm this coming summer jackson brill who is a student at the university of colorado and he is also a solomon runner and he is also one of our former interns one of the better interns that we've ever had and i've actually had a lot of them but the real reason that we wanted to bring jackson on the podcast today is because he has done a unique piece of research in conjunction with his undergraduate honor study studies at the university of colorado where he looked at this confounding question that trail and ultra runners all over the world have to confront on almost every single run that they do and that is is it better to walk or is it better to run up this hill and to be frank with

everybody we don't have really good answers for that the research hasn't really uncovered a good answer to when you should walk and when you should run should you base it off a heart rate should you base it off of grade should you base it off of speech you base it off of just dumb luck we honestly really don't we really don't know we know what that means in a flat level condition researchers have studied that for decades but we don't know what that means in an uphill condition which is extremely relevant for trail and ultra runners and so he happened just happened to do some research during his undergraduate studies to better explain and to better illuminate this very topic and we dive into a lot of that on this very podcast so you guys listen up buckle down here we go here's my conversation with jackson brill about should you run or should you walk that hill in front of you let's kind of kick things off because i think what you've been like the problem that you've been trying to solve in your in some of your undergraduate honors uh studies is a kind of a common problem with a lot of ultra runners out there is they're trying to determine like when it's better to run and when it's better to walk on the uphills and we've all had this experience where we're in a big race and there's a lot of people around and you're climbing up some climb and you can look ahead of you behind

you to the left and to the right and half the people are walking and half the people are running but they're all going the same speed and i think inevitably whenever when anybody does this the more and more people look around the more and more people start intuitively walking because they look they look to their left and say oh this guy or this girl's walking i might as well start to walk and they look up the up the mountain they're like oh that person ahead of me is walking what i should be walking as well but how like how did you initially kind of become interested in studying this yeah so as as you know and i guess hopefully the listeners will now know i i live in boulder uh colorado and we've got a lot of steep climbs where uh in a lot of cases walking is the most efficacious gate to choose uh you know some of the steep climbs like fern canyon and shadow canyon up some of the peaks and uh and then you know there's some some more moderate stuff where yeah it's it's not super well known which which you should do and you know you'll go out for a run with a friend and i might be running and they might be walking or vice versa and inevitably it leads to conversation and uh yeah i think i think this is a the conversation of you know when should you run when should you walk oh do you run that climb or do you walk this climb it's a conversation i think most of us have had yeah and i i can tell that you have been studying and thinking about this a lot because you intentionally use the word efficacious

and not i know you're laughing because you know where i'm going with this and you didn't use the word efficient or economical and this this starts this this becomes a really good like launch point into what you were specifically studying why don't we kind of broadly give a broad overview to what we know about the run to walk transition and these two these kind of two different points that you initially started to look at which is the preferred walk to run transition which is which what people just naturally start doing and then the well you can describe that you can describe the second one since you uh since since you've studied it and i think it i think it i think it uh also is related to the like the specific phraseology you were earlier using yeah so there's been a lot of research done on flat terrain uh about uh when it's best to switch what speed it's best to switch from walking to running at uh and you know and as you mentioned that's the preferred transition speed or one of the transition speeds is the preferred transition speed and that's that's the speed at which slower than on average people prefer to walk and faster than people prefer to run and up until i some like somewhere in the the 1980s or early early 90s people just assume that that preferred transition

speed was also the speed uh that was most economical to switch at so slower than the preferred transition speed walking would have a lower energy cost than running and faster than the preferred transition speed running would have a lower energy cost but then then in the late 80s early 90s they started realizing that there's actually a difference between when people preferred to switch gates and when it was actually the most economical to do so so the preferred transition speed is is there's you don't really have to uh you know measure anything in a lab in the sense that you don't have to measure you know anyone's oxygen or uh carbon dioxide uh but but there but so yeah preferred transition it's just based on it's an observational study i think is what you're getting at and they've done it all over the world they've gone to different you know corners all almost all six out of seven continents and just observed people walking down the street walking through malls walking kind of to church or wherever and they can measure their speed while they're doing that and aggregate all of this data and as you mentioned it's not a physiological phenomenon that they're looking at they're they're simply looking they're simply observing people in what speeds they prefer to walk at in the transition with which they start to they start to become they start to actually run right and yeah so so that preferred transition speed in the 1990s some of the researchers began realizing that's different than

the speed that it's energetically optimal to switch at so there's this disconnect between the preferred transition speed in humans and the energetically optimal transition speed in humans yeah so on on flat train the preferred transition speed is about a 13 and a half minute mile so slower than 13 and a half minutes per mile people would generally prefer to walk and faster than a 13 and a half minute mile humans would generally prefer to run but if your goal is to minimize how much energy uh you're burning if your goal is to just conserve energy then the act then the speed that you should switch at is a 12 minute mile so there's this there's this disconnect where you know let's say you're you're moving forward at a uh a 13 minute mile uh most people would prefer to be running at a 13 minute mile despite the fact that running is actually the more expensive gate yeah it's interesting that it's interesting uh again the way that you phrase that because a lot of times in biomechanics and physiology research we tend to oversimplify concepts with bioenergetics and we tend to look at things like running and locomotion economy as this sole driver of what humans do and so much so that it becomes i i my personal opinion is i think it

becomes a an overly narrow focal point for coaches and physiologists to like boil down things like performance and you know and and and the whole host of like battery of aspects that we're working on with athletes and that's not to say that running and walking economy is unimportant but it's not the solely important thing so needless to say the discrepancy between the preferred uh run to walk transition and the energetically associated run to walk transition those are different and that points out that there are other things that are going on within this run to walk transition that are not related to the bioenergetics or the energy cost so why don't you go ahead and explain what some of those things that i guess the the right way to put this would maybe because it's not fully you know it hasn't been fully flushed out in the research quite yet yeah no and i think you you bring up a good point where i think definitely on the practical side of things coaches and athletes very much look at at training and stuff from this this energetic lens you know i think we're all familiar with terms such as vo2 or vo2 max you know lactate threshold you know running economy and we're maybe less uh as a as a as a broad statement like we understand less about the biomechanics of of of locomotion and of of performance so so yeah i think you bring up a good point that yeah a lot of people do look at this mainly from this

energetic lens and the fact that there is this disconnect between what people prefer to do and what's energetically optimal shows that um shows that just looking at things from this energetic lens is is a little too um simple so so yeah when um so yeah because there's this disconnect between those two uh speed transition speeds um a lot of researchers have looked at the the biomechanics of uh of running walking to see if if that can explain the difference so there's been a lot of research done on differences in muscle activity and the way different muscles are activated and the patterns of when muscles are on and off they've looked at uh how joints move uh they've looked you know the the joint forces ground reaction forces they've looked at uh joint velocities and joint accelerations so looking at these more biomechanical parameters that aren't looking at the energy cost from this global whole body perspective but looking at it more centered around a specific muscle or a specific joint and and there's been again like you mentioned that there isn't a scientific consensus on flat train what's triggering the the um gate transition to occur at the speed that it does but uh there's been a lot of evidence it's more of a biomechanical phenomena yeah and some of the theories that get thrown around as you mentioned might be due to specific muscles but also this overall biomechanical load is the way

that i'm gonna is that i'm the way that i'm gonna actually describe it that there's some phenomenon as you mentioned around the joints around the musculature that signals to the brain hey you better start running versus walking right now because it's easier for us even though it's not energetically optimal that's part of the theory at least right so there's uh the tibialis interior which is the the muscle at the front of the shin there's been a lot of research uh that finds that that's a lot more active in walking than in running so uh a lot of the research that's been done has concluded that you're basically that chin that muscle at the front of the shin that tibialis interior is overexerted when you're walking at fast speeds and that the reason why we switch to running is because then the front of your shin that muscle is is less uh less active and thus um isn't in a state of overexertion once you switch to running so it's so that'd be almost like a limiting factors approach right there's a muscular limiting factor to that form of locomotion to where your body says hey listen this one this one specific action with this one specific muscle is going to get overloaded past a certain speed and then therefore that is signaling to your brain to transition to a run even though it's more energetically expensive which is kind of an interesting kind of an interesting hypothesis right that that one specific muscle or the power around one specific joint could control

things so that it would drive you to a less economical form of locomotion locomotion right yeah and if we if we keep looking at at that specific um tibialis interior muscle it's not a large muscle right so uh that's that's kind of one of the reasons why it it wouldn't be contributing to the energetic the global whole body energetic cost is because okay even if it's even if we could look at um the energetic cost of that specific muscle and see that it's a lot higher in walking than running you know it's such it just doesn't have as much muscle mass as some of the muscles like the glutes and the quads and the hamstrings so um which are going to contribute to the overall energetic cost uh of locomotion more so like let's let's say and there's been some research that shows this the quadriceps you know this big muscle uh that's that contribute a lot to to energetic cost let's say they're two percent more active in running than walking but the tibialis interior is 20 percent more active in walking than running that that small difference uh in the quadriceps is going to potentially have a larger contribution to the energetic cost than that really large difference uh in the tibialis interior and that's that's been one of the one of the thoughts as to why there's that disconnect is maybe these big muscles are a little more active in running than walking but the difference is so small it doesn't contribute to your feeling of uh of fatigue and exertion while that big difference in the smaller muscle um is is

you know you you can recognize that discomfort in walking yeah so it it's this this area has been fascinating to me because we've been describing two points right we've been describing this preferred walk to run transition speed where humans just instinctively prefer to run versus walk and we've been and we've been describing this uh more energy uh energetically uh favorable run to walk transition which is the which is the energetically optimal transition speed uh as defined in the research but really when we think about it if we think about it as athletes and coaches there's really a third variable or there's really a third speed that takes into consideration not only those two points but also a whole host of ones and that's really the strategic transition point for an athlete to actually use while they're out there in the field and that has a little bit to do with energetics it has a little bit to do with biomechanics it has a little bit to do with strategy and probably 30 other variables that we could eventually tease out if we had enough time and resource to actually do so and this third transition speed that you're talking about there's no research on it we have no idea uh what speed is the correct speed to um to transition gates at uh if the goal is to just go as fast as you can because it you know we don't know if what people are preferring to do will make them go the fastest we

don't know if uh if what makes people the most energetically um if yeah like the most economical is the uh results in the best speed or if it's somewhere in between or if it's somewhere even slower even faster than either of them so uh yeah the way that i normally boil it down to a practical standpoint though is one way to look at it is through the energetics like if your goal of part of your overriding strategy in an ultra marathon type of event is to minimize the energetic cost of going from point a to point b mile one to mile 50 mile one to kilometer 100 mile one to 100 if that's a big overarching strategy you sure as heck would be well served to steer towards this energetically optimal transition speed whatever that is at whatever grade but if part of your overarching strategy is to essentially essentially preserve the musculature and to try to spread the load around which is not a really scientific term but a lot of people understand that they want to be able to spread the load around then this run to walk transition as we're going uphill it it takes on a little bit of a different context because you're using it to spare the local fatigue at the level of the muscles even at the expense of in a lot of cases even at the expense of extra energy extra oxygen extra calories and things

like that yeah i mean i think if we look at why people use poles and ultras uh it's generally not to be more economical it's to just keep their muscles from getting too tired uh you know as as yours or yeah so um so right it's you whether whether it's better to be more economical or to save certain muscles from being overexerted uh determining which is you know which will result in the better performances that's hard hard research to do i know exactly okay we're we're going to try to stay off of poles for a little bit we might be able to come back in another podcast and talk about that let's let's kind of let's let's leave it there and and and come to the consensus that the right or the correct run to walk transition and how you determine it in the arena of trail and ultra running is undetermined and it's a lot of it's a lot based on the individual let's dive in a little bit more into the research that you specifically did for your honors thesis what was the what was the primary question that you were trying to answer with the research that you did yeah so the primary uh yeah what we were primarily trying to do was determine how transition speed uh both preferred transition speed and energetically optimal transition speed how that was affected by incline uh because all the everything we've talked about up to this point uh has been mainly about uh when the transition on

flat terrain but if again looking at it from the practical point of view that's not really that interesting to to trail and ultra runners you know we're we're generally able to move fast enough that on flat terrain we're able to run uh so so i was more curious about looking at it in an incline um on on inclines because that's actually where trail and ultra runners will walk yeah so set the experiment up why don't you just describe the research protocol who you brought into the lab what it looked like and things like that and then we'll go over what you actually found out sounds good so uh we looked at four different inclines uh we looked at uh a flat so uh zero percent grade we looked at uh five degrees or uh eight point seven percent incline we looked at uh 10 degrees or 17.6 percent and then finally we looked at 15 degrees or 26.8 percent so i i'll keep it to percent from here on out uh for the for the sake of that's probably what most people understand uh intuitively so yeah uh zero zero percent nine percent eighteen percent and 27 percent grade and we were looking at uh subjects preferred transition speed and energetically optimal transition speed at each of those four inclines and uh because most athletes don't have the ability to determine their energetic cost uh in the field you

know i don't i don't think really any of us have just a spare portable metabolic cart that we you know take running with us so we also looked at heart rate uh to see if heart rate uh could serve as a good um proxy for either of these two transition speeds and you let's describe the experiment protocol first so describe the subjects that you brought into the protocol because i think this is actually important like important in terms of the protocol itself yeah so our subjects consisted of um 10 pretty elite uh male trail and mountain runners so uh the reason why we kind of kept it to the pointy end of the um of the field was because it's really hard to actually find people who are fit enough to to run fairly comfortably at that uh 27 percent uh percent incline so um that's why we ended up being a bit elitist in our uh in our subject pool which is i mean that's standard protocol for a lot of exercise physiology a lot of biomechanics studies where you're looking at elite males and i assume they're college age males too yeah i not necessarily college stage it was uh i was probably the youngest subject uh at 21 and the oldest subject was 40 okay so it was more just uh local local badasses i know in boulder yeah yeah boulder has this you know pretty good research subject group there just because of your populations okay so you had these four different you had these four different grades that

you were uh that you were studying runners at zero percent eight point seven percent seventeen point six percent and then 20 20 we'll round up to the nearest percent how's that yep and to give the listeners a little bit of a perspective on what those different inclines would be like in the real world zero percent obviously flat right track road bike path things like that nine percent your first your uh your first condition that would be that would be roughly like i think the way that you were describing it is is uh chapman drive or bear canyon there in boulder um it would be shallower than the pike's peak ascent which is about 11 or 12 percent so anyway a hefty grade not too serious but a hefty grade most most people will be running that grade uh in a shorter distance race or if the climb isn't that long that's a good that's another good perspective okay so your next uh your next condition roughly 18 percent what are we gonna what's our what's our analog for that yeah so uh 18 percent would be pretty steep uh i think what was the you have the um what i said was similar to it why don't you say that it's the front side of green mountain via ranger and gregory that's a that that most mere mortals is going they're going to

walk that yeah on a long on a long climb uh most people will will walk that are in the context of an ultra marathon they'll walk uh a grade that's steep but if uh if the climb is you know only a few minutes long or uh if it's a shorter race like maybe a a vertical kilometer or something like that yep as some people would still a fair amount of people would still be running okay and also for athletes that have done the leadville trail 100 it's almost it's almost as steep as the back side of hope pass 18 and 18 percent grade steeper than the front side front side has a little bit less climbing just because the way it's set up backside it's it's it's pretty darn close so that's your third condition hope pass green mountain via uh ranger or gregory your last condition this is where it starts to get hard so this is 20 27 grade and i'd have a hard time finding something that's a 27 grade but i think that uh uh the cunningham climb on the hard rock course in the clockwise direction so it's the very last climb with 10 kilometers to go that's about like a 30 or 28 grade depending upon where you're actually marking it from but my point with that is is the steeper parts of hard rock is going to be about a 27 28 30 grade which is your last condition almost in a in a real world situation hardly any runners are going

to be running that except for the best of the best and that's when they're going hard right yeah so um headwaters ridge uh which is one of the steeper climbs at the rut is is similar a comparable grade to to that 27 so right yeah it's it's we're looking at very steep um that right in the context of a multi-hour race uh on technical terrain potentially at a higher altitude people are probably aren't going to be running that so so the lens that you're looking at this through with these four conditions zero percent is obviously runnable for almost everybody that's your first condition 8.7 percent is runnable but hard for for for almost everybody especially if the climb is a little bit shorter your third condition 18 that's like a coin flip you know should you run it should you walk it you know depends on how good the athlete is how long the climb is and things like that and then your last condition unless you're going as hard as you can almost everybody should be walking that is that is that kind of philosophically where you're setting those uh where you're set where you're setting those slopes yeah yeah i mean we're spanning the we're spanning the range of inclines between where nearly everyone's going to walk and are on flat train where nearly everyone's going to run and on steep train where nearly everyone's going to walk so yeah looking at that that practical range okay and i think this is a good point to interject here the lab that you guys have there at the

university of colorado is one of the few labs in the world that are that is that's capable of research like this and i'm not and i don't know how you obviously didn't max out your steep incline uh treadmill but there aren't a lot of other labs in the world that are set up to do these really steep incline studies because the equipment that the treadmill literally doesn't exist to go that high right yeah so our lab we boast the steepest treadmill in the world and we actually didn't use it for this study didn't oh okay no we used we actually just used uh an old treadmill from uh that's probably four or five times older than i am that's a bit of an exaggeration but uh but definitely this this pretty old treadmill um but yeah we we have another treadmill that has the ability to go up to a 45 degree um incline which is 100 grade where you're actually um you're climbing just as much as you're moving forward yeah okay but we but yeah we didn't we weren't looking that steep because you should probably just walk if it's that steep i guess it would be better to say the future of this research as you expand on how difficult you can make the research conditions would be contingent upon your steep inclined treadmill yeah i mean so the the research we were trying to do um this transition speed research on our third at 30 degrees on our steep treadmill and we just couldn't find anyone who was uh fit enough to to actually run um at a speed where uh it was more economical to do so so i there was one day

a few summers ago where they just put me on that treadmill and pushed me as hard as i could until i was on the verge of collapsing and uh and still i i wasn't fit enough to um to reach a fast enough speed where we're running made any sense okay so let's get back to let's get back to the research protocol first right we've got these four grades flat not very steep sort of steep super steep we'll call them that right we'll use a colloquial definition what did you take each of the subjects through to determine what these run to walk transitions looked like yeah so first uh we determined their preferred transition so just uh not doing any sort of fancy uh not doing any sort of fancy lab measurements but just determining the speed at which uh they just chose on their own to transition gates at so um to do that we uh we had to average their run to walk and walk to run transitions so um for the run to walk transition we started the treadmill at a very fast speed um that subjects you know undoubtedly preferred to run at and then we slowly lowered the speed of the treadmill until eventually they told us oh you know that's the speed that now i want to walk at and then we did the opposite for the walk to run transition start the treadmill very slow subjects wanted to walk incrementally increase the speed of the treadmill until eventually oh that's fast enough where now i want to run so we so we determined

that that preferred transition speed uh across all four of those uh inclines and then we did the same thing uh for their energetically optimal transition speed so uh to determine to determine their energetically optimal transition speed was a little bit more difficult we had to uh we had to have subjects uh both walk and run for five minutes uh at three different speeds uh and then we plotted the energetic cost of both gates for those three speeds and then we had to crunch crunch some numbers and do some math and uh you know create a an equation for how how the energetic cost of running and the energetic cost of walking changed as a result of speed and we had to do that then for each incline so we were plotting these linear regression uh lines for walking and running for all all 10 subjects all four inclines so 40 different total conditions uh and then the intersection point between walking and running uh for each of those 40 conditions uh you know was was the energetically optimal transition speed so we collected collected all those uh and then as part of those energetic trials we also uh collected heart rate data uh to see how heart rate uh to see if heart rate was um was a good proxy for energetic cost okay so so now you've got these three points right you've got the point across all of your different conditions right your flat condition your sort of steep condition your really steep

condition the super steep condition you've got the preferred run to walk to run transition across all just the preferred transition yeah the preferred the preferred transition speed thank you for correcting me that's correct the preferred transition this is why you're in school and i've been out of school for 20 years you have the preferred transition speed across all the conditions so that's the one where the where the subjects say hey listen i no longer want to walk i'm going to start running vice versa yep you have the energetically optimal transition speed which you've taken from a metabolic cart across all of those different conditions and then you also have the heart rate that's correlated to one or both of those conditions so so that i mean that's what we were testing so we we collected the the heart rate data at the same time as the energetic trials okay and then after the fact we're going to see um see how um the heart rate response compared to um to the other to the preferred and the energetically optimal transition speed perfect so we we've known let's try to summarize the old research and then your research we've known that the preferred transition speed and flat level walking is different than the energetically optimal transition speed we went through we went through that at the beginning yeah and that's extremely well established it's extremely well established does that extremely well established point or points hold true as according to according to the

research that you did as the grade change meaning are those points still apart or do they start to converge as the grade increases right so i think there's been maybe only there's only been one study in the past that looked at both preferred transition speed and energetically optimal transition speed on inclines and they they were looking at um less steep inclines uh so so yeah our research really was groundbreaking in terms of how steep uh how steep we're looking at um both the preferred and energetically optimal transition speeds so uh yeah zero degrees right we saw what we expected to the preferred transition speed was slower than the energetically optimal transition speed we continued to see that at uh at nine percent we continued continued to see that at 18 and then when we got to the 27 grade we actually saw that the average preferred transition speed and energetically optimal transition speed converged and there wasn't a difference between the two anymore uh on average so yeah so okay so rather interesting meaning and this would imply and i think we should add the caveat that small subject group first piece of research that's done that's been done at this uh type of uh at this type of incline that it needs more validation but it would appear to indicate that as the grades get steeper

somehow those two points converge yeah if you took if you took that uh that difference being zero at face value yes that would appear that the two converge but yeah just to expand on on the caveats you said um only about half the subjects actually saw that convergence at at the steepest incline the other half of the subjects a few of them their preferred transition speed was uh greater than their energetically optimal and a few transition speed they're energetically optimal is greater than their preferred so it ended up averaging out uh to be zero but if you if you actually looked at the graph and and looked at how much variance there was uh i think it'd be a little irresponsible for me to say um you know we know for certainty that this convergence occurs uh you know in everyone and that's just the way it is so definitely some more research needs to be done on how on how the preferred and energetically optimal speeds um how the relationship between the two changes um on these steeper inclines jackson you've been schooled well because we we look at this all the time with different training interventions and it's anything with you know caffeine to a nutritional supplement to altitude anything that's kind of looked at as an ergogenic aid and when they're looking at these pools of people as you just very well described sometimes the average is two percent better one percent worse or whatever but then when you look at the individual subject data there can be one outlier

that influences that average or it can be a 50 50 split between the the number of subjects that improved versus the number of subjects that showed an actual decrement and what what i always kind of come back to is when you start to see those when you start to see those kind of like evenly split ergogenic in the in the ergogenic space when you start to see those type of evenly split results in the subjects you're just flipping a coin at that point and you don't know if this aid is going to work with this particular athlete or it's going to or it's going to make that worse we fell into that fallacy a lot in like the early 2000s with altitude training until we started to really scrutinize it a lot more and turns out half the people can get worse in an altitude camp so anyway good good that you pointed that out okay so let's start to talk about the heart rate data that you collected why don't you describe what that looked like what your hypothesis was of the heart rate data and then what you actually found out during the research right so uh heart rate in general does uh correspond fairly well with energetic cost um and again you know the heart rate does have you know some variability and uh and it's not this this perfect uh metric and as you've talked about in your book and articles and stuff i think um we know heart rate's not perfect but it it does generally do a pretty good job of estimating energetic cost so we wanted to see if um if that would hold true in on these on these inclines because

yeah if heart rate can tell you when when you should switch grades or when you should switch gates um to be the most economical like that would be really cool uh unfortunately uh heart rate had too much variability and um and wasn't uh an accurate enough uh guide or predictor for for the energetic cost so uh so we what we had hoped to see um was that at um was that at speed slower than the energetically optimal transition speed uh heart rate would be lower and walking uh and then faster than the energetically optimal transition speed it would be uh it'd be the heart rate would then be higher and in walking hopefully i i said that right um but basically we expected uh if we plotted heart rate in walking and running we expected to see this heart rate optimal transition speed to correspond with the energetically optimal transition speed and unfortunately we didn't see that um heart rate was kind of all over the place uh relative to the energetically optimal transition speed uh and thus you know it isn't going to if you're trying to use heart rate to tell you um when is the most economical uh speed to switch gates at uh you shouldn't it's not going to do a good job yeah and that's that was a surprise yeah i mean are we hypothesized that that uh yeah we hypothesized the opposite of

what we ended up finding yeah and and so when i looked at it and i haven't expressed this to you yet i know i you know i i attended your presentation and things like that but when i look at it from the bioenergetic standpoint one of the things that i take away from that and we can bat this around a little bit one of the things that i take away from that is the bioenergetics for somebody running on flat level ground as it correlates to heart rate is different than when they're than when you're climbing and different running and walking climbing meaning if we were just to say jackson your lactate threshold we go we go we measure in the lab your lactate threshold heart rate which would be a bioenergetic property right your lactate threshold heart rate is 168 beats per minute as we determine in the lab your lactate threshold heart rate running up a 20 incline is not going to be 168 beats per minute your lactate threshold heart rate hiking up a 27 incline is not going to be necessarily 168 beats per minutes as from a coaching standpoint though that was one of the things that i extrapolated from this initial piece of research and i'm wondering did you or did your professors have a similar or different extrapolation on that or did it wasn't even part of it uh yeah i don't think i've even thought about uh thought about that but but no i think you're you're spot on and saying that right the fact that

the fact that heart rate wasn't this good predictor of energetic cost uh in terms of gate transition yeah you could totally extrapolate from that that um you know you're using heart rate to define lactate threshold or view to max or whatever uh you know there's a good chance that's not gonna work uh on incline terrain if you know it was only measured on on flat train in the lab and i think you know even for if we you know take took another step forward with it you know if you have athletes doing schema races or something uh and you know you there is this new sport they aren't as comfortable with it you say oh okay just just go off of heart rate because we know this is your your heart rate in certain you know similar efforts on in running yeah it's not necessarily going to work very well well the now actually the analogy now that you think about it that i would take from it is that we would never say okay your threshold your heart rate ranges for cycling are a b and c we would never say that your heart rate your heart rate ranges in running are the exact same a b and c as they are in cycling the analog that we can extend from the research that you did is if we have heart rate ranges or if we're using heart rate ranges for running that are a b and c they don't necessarily translate to a b and c as the grade goes up and or as you switch from running to walking it's the exact same problem that we have when we

completely switch modalities from cycling to running or from running to schemo we don't blanketly apply the same heart rate ranges for a whole host of reasons but it's not as intuitive to take to take that same extension from running on flat level terrain to running and hiking uphill yeah i mean we we all know and understand that running and cycling or running in schema are different sports but but yeah i mean even running on flat terrain on roads is to an extent uh maybe not entirely a different sport but uh it's it's not the exact same as running or hiking um on steep you know uphill terrain so so yeah it's it's funny because the way i think about trail running is i think of it's a mix between backpacking and road running and you know backpacking and road running are entirely different sports uh and this you know this trail mountain running thing it's it's kind of like this halfway different sport than than this road running that uh that a lot of people kind of know and understand yeah anyway i mean i i've we've we've if i lean on my cycling coaching background you know 15 years ago or something like that we've always applied different heart rate and power ranges to to a certain extent in a in a climbing in a climbing situation versus a flat situation and it was for a while that was controversial to do because a watt is a watt is a watt right but we started to recognize that just from a

practical standpoint athletes could produce more power climbing than they could on flat level terrain and therefore their heart rate ranges were a little bit higher climbing than they were on flat level terrain for cycling it's easy for somebody to say oh well of course you're running not cycling they're different sports so we're going to do things differently but it's not as intuitive for most people to say hey listen running uphill especially the steeper the uphill gets those same heart rate ranges and things like that might not be the same indicators of of uh economical cost or the bioenergetics that are actually going on as compared to flat level training that part to me is actually quite fascinating and like i said i've hypothesized that for years but i've never outside of just like personal trials and trials with my athletes and things like that where we're just dorking around the treadmill we really don't have anything to point to it other than just anecdote yeah so okay let's get back down to brass tacks here so why don't we first why don't we first kind of go since there's all this like stuff that we now you know it's like once you do a study you find out like 10 things you're like oh man now i want to know this and now i want to know that it's the proverbial rabbit hole right what what are the proverbial research rabbit holes that you want to go down next based on this initial research that you did and then what we're going to do is we're going to come back to like the broad recommendations for athletes right yeah and uh and yeah as you say you know there's there's 10 different places i could

go here but i'm going to limit myself to because you know next year you know i'm in the lab uh you know getting my master's uh next year you know i can't do 10 studies i'm only going to do one so uh so yeah maybe this will this will help me figure out which one i want to do but i think i think looking at the um investigating further this preferred transition speed and energetically optimal transition speed convergence or just the relationship between the two on these steeper inclines that warrants further investigation um to see if our our finding at our steepest incline that the two were the same uh was just kind of a result of of dumb luck or if that's actually um actually like a legitimate um a legitimate finding that is just uh a fact that's just i guess um so so yeah just to see how if if the preferred transition and the energetically optimal transition speeds converge on these steeper inclines and there's intuitively it makes sense that they would because uh you know the fitness required and the exertion required to um to run right at these steeper and steeper inclines gets harder and harder you know we can all run on flat terrain you know most of us can run at a moderate incline and then very few can run at these super steep inclines so because energetics uh energetic cost is higher um at the at or near the transition speed on these steeper inclines it would make sense then that we need to

um we need to uh care more about economy and energetic cost uh and maybe even less about biomechanics because at these steeper inclines if you're running energetic cost becomes this large limiting factor so investigating if that theory um if that theory holds any you know holds water uh that would be one thing we want to do uh i'd say the the second thing um that i i really at the forefront i really want to do um would be just getting back to the performance um the performance side of things uh you know as you mentioned pretty early on okay we have this preferred transition speed we have this energetically optimal transition speed and we really have no idea uh you know which one will whether switching gates at one or the other will allow us to um to perform better to get up that hill faster so uh if if it makes sense to um transition speeds when we prefer to do so uh or let me let me phrase it a different way uh i think one thing we want to do is perform time to exhaustion tests between running and walking at the energetically optimal transition speed because we could we could put people on a treadmill 15 degrees we know um we know approximately or we could even determine their their energetically optimal transition speed uh and then we could see in which at the same speed which gate um allows them to to go for longer uh and let's you know because that energetically optimal transition

speed uh i guess at uh at the more moderate inclines is is greater than the preferred transition speed you you could you could it makes sense that then uh um you would last longer running at the energetically optimal transition speed than walking because you know that preferred transition speed is lower so you would think subjects hate to walk at that energetically optimal um transition speed so then they'll they'll crap out earlier walking so um yeah investigating and that'll kind of start to answer that question uh okay should we transition closer to our preferred or should we transition closer to energetically optimal transition speed and then that kind of would give some practical uh application to okay i'm hiking up this hill you know is it better for me to switch to running or you know is it better to stay walking because right now right now we don't know and and actually my advisor uh dr roger crom and i we kind of have a different hypothesis on what we expect to see from uh from that uh future study that's to be to be really frank with you that's the money study like that's the one that you're going to get the most bang for your buck like coaches i could take that i could take the results of that and if it were you know replicated in some form or fashion across different labs and i could directly apply it to athletes and a whole host of situations by extrapolating the the data from the trials and then what i know about my individual athletes and what their threshold is and you know things like

that that one so if if you were getting a nudge from me do like do that one because i can implement it i i'm reminded of um this this this company that's now owned by training peaks called best bike split where they have this mathematical model that's based off of physics that will give you a cycling pacing model for any course out there based on power and the problem and the problem that that cyclists have with time trials is that it's not always in their best interest to evenly pace a time trial based off of power because of this cuboidal res uh uh relationship between wind resistance and speed so as you go as you try to pedal harder and you go faster the amount of wind resistance that you actually are in uh encountering is disproportionately uh uh related to the amount of power that you actually have to produce and so and so the practical outcome of that is the slower you're going the more advantageous it is to produce a little bit more power to squeak out speed gains versus when you're going 50 miles an hour and you you know it needs you need 20 more power to squeak out an extra tenth of a mile per hour you could take that same and so anyway the outcome of that has been kind of like these like power heat maps that um that coaches have produced for different races ironman races time

trials and things like that that are basically telling the athletes what the optimal power range is to produce the best result the analog and trail running could be essentially when to run when to walk based on that particular athlete and and the course profile that's almost what i'm seeing could be developed out of something like this yeah no i completely agree it's um it is this uh you know money study as as you put it um you know doing this uh time to exhaustion comparison between running and walking and not only is uh i i not only is yet it really applicable for coaches and athletes but it's also um it also will give us a a good understanding of what to do in the future for research because right now we don't know is it better to chase looking at biomechanical differences at the preferred transition speed or is it better to you know you know look at uh you know look at metrics more at this energetically optimal transition speed because ultimately i'm doing this research because i want to know you know when should i walk when should i run to race faster so uh you know this uh you know doing a performance specific study is important to kind of figure out you know where do we where do we go from here so yeah i i'm taking your your vote into into consideration for sure as to what we do next year you'll you'll have you'll have uh you'll have the first competitive advantage because you'll know the research before it's published

right totally selfish on your part well yeah it's it's it's funny because uh i did a 50k in the fall and uh the person i was running with was switching between walking and running based off of what i was doing and i don't i don't think he knew that i'd you know done any of this research but i was like damn i gotta be i gotta be careful because you know people if it gets out that i'm doing this research everyone's just gonna look look to what i'm doing and assume that i know best which i i don't think i i don't uh we're still a long way from knowing uh or at least we don't know yet uh you know uh which which is the best yeah best speed to tune or what best speed to tune yeah it's not going to be magic right one study is never magic but i do think that the initial stuff kind of uncovers a lot to to to go off of i mean we still we still lean on research from the 30s 40s 50s 60s 70s and 80s you know to apply sound training principles to what we do now even though there's been further research to to dial down on any particular topic so the initial type of research always has a big influence on what's to come um so let let's let's leave the listeners jackson with what are the what are the practical recommendations that they should be taking with them out on trails if they don't have you to follow into mimic like how can runners actually take this and go okay what's the what are the reasonable ways that i can determine the best transition between walking and running and back again

yeah you should time stamp this in the podcast so everyone can just skip straight to it but yeah so uh i think i think one of the yeah i think uh one of the the big takeaways is uh there's no magic speed and there's also no magic incline at which you should switch you know i've i've read plenty of articles uh you know out there that say at x incline this is when you should start walking or if you're moving slower than x speed this is when you should start walking and it's not that simple it's this transition speed because all both transition speeds that we measured we're getting slower with incline it's some combination between incline and speed that determines determines when you should transition gates so uh if you're just looking at your watch um or you know if you if you're measuring if you know how steep these inclines are and you're using and that's the only thing you're using to determine whether you should walk that's not a good approach because it's it's this relationship between speed and incline um in terms of yeah figuring out uh yeah when when you should switch sorry do you want to say something no well what i was gonna say this is a failure of audio here i was like i was kind of throwing my hands up in the air a little bit and indicating that i was gonna jump it but um so we we do this a lot in coaching we're like okay this says to not do this right i mean

so you've got the research that says that you're you're absolutely right there's no magic speed there's no magic grade but what people want to know is not only what not to do right not to focus on speed and or grades specifically but what to actually do so what do people actually what like what is going to tell them what can they actually use in the field since we're saying don't use the grade and if you can determine the grade in the field great but you can certainly determine the speed right you can turn your watch over and say okay i'm doing you know 20 minute miles 24 minute miles or whatever since since we're not advocating for that either and as your research indicates heart rate doesn't indicate either one of those what's the reasonable solution yeah so uh you know it's not sexy but um going off of you know rate of perceived exertion going off of your gut you know what what just what feels the best because you know we've done this research you know we could probably create this you know multiple regression type equation uh with four or five different variables telling you okay you know optimizing these this is when you should transition gates but your brain can run this multiple regression type analysis for hundreds of hundreds of variables so um if walking feels feels good that's what you should be doing if running feels feels like it's faster that's what you should be doing and and really kind of going off of off of rpe um you know based on based off of what what your brain's telling

you is you know it's not sexy and it it may be it's unfortunate that despite all this research we've done it's it still is that simple but um but yeah there's really not uh there's really not anything better out there right now and and i definitely think we should think about it uh and and really be uh be present when we're um you know when we're climbing these these hills and and you know maybe transitioning back and forth uh you know throughout throughout uh um you know training sessions to kind of uh get a feel for um for for the differences you know that we're we're picking up on between gates um but yeah it's pretty simple just just trust your gut and uh and that's probably the best thing out there right now it's interesting though because you know a lot of athletes aren't that intuitive and there's probably some nuance like when you're looking at your little sphere of people around you you know the five or six people around you in the example that i mentioned earlier half of them are going to be running and half of them are going to be walking yet they're all kind of traveling the same speed but we also know and like i said there's nuance in that right and we could probably tease apart okay that person should actually be running and those two people should actually be walking and these people should be walking half the time and running half the time but sometimes from a coaching perspective we're we're we're trying to avoid the bigger negatives the times where you should clearly

not be running and clearly be walking you're trying to tease out like subtle nuances right like the difference and i think this is important to to point out the the difference between the energetically preferred transition speed and the preferred sorry the energetic the energetically optimal transition speed and the preferred transition speed is how much it's uh i mean it's dependent on incline speed and everything but ballpark ballpark yeah it's uh probably between one and three minutes per mile okay uh on on most inclines okay so we'll split the difference right let's just say it's two minutes per mile so the difference between like 18 minutes and 20 minutes per mile we still know some people and everybody sees these people out there on the trails that are running at or trying to run this is dependent upon your biomechanical definition of running they're trying to run at 28 30 minutes per mile they've got the little shuffle step going on so clearly there's some sort of like wiring that is going awry with those people trying those people that are thinking that a run is better for them than walking yeah so i think a lot of people maybe come and a lot of the people that you're describing they come to the sport from this road running or track running background uh and they're they're scared

to walk you know they've uh in the the context of you know that this road running sport you know you you run every step so um so yeah i think encouraging athletes um to get away from that mentality of running so of that they need to run everything uh is is a is definitely a good thing to do because yeah uh there's especially in the context of our sport of trail trail and uh mountain running there's going to be times where it's better to walk for sure i've sometimes given people governors and say listen and i know you're not advocating for a specific pace but like ridiculous governors like if you're seeing 28 minutes per mile on your watch i don't care what grade you're at you need to be walking you need to be walking on flat level ground at a 28 minute mile and every other inclined after that right unless they're killian who can run up you know a 40 degree uh slope you know that 28 minute mile you know probably is best to best for people yeah yeah yeah but you know outside of the five people that could actually accomplish that on the face of the earth tell him when when he should be running and walking no he's got it he's got he's got it wired but i do i mean i do find that from a practical perspective as a coach as much as as much as i like to lean on intuition and rate of perceived exertion and hone it intentionally through the training process and make athletes think about hey what are you running when you walking what's your you know what's your rpe during

this climb this to stand i mean that's a big part of my coaching philosophy i still have athletes that when i go out to the races and i'm standing on the side of the trail and i see them running at a 30 minute mile i'm just like god you're like you need to hike this hill how can you not figure that out yeah and i think it's one of those things that gets better with practice like when i first moved to you know moved to boulder and started started college you know i was fresh off of high school cross country you know i didn't i didn't walk i was a runner uh and you know slowly through i think my first two or three years in boulder you know originally i would just try to stubbornly run every step of every climb and you know eventually i would try to start walking and you know sometimes i'd look at the watch realize i was getting up these climbs faster even though i was walking more um so yeah it's definitely something that i think you get better uh you get better with practice at um and just just once you realize it's okay to walk uh and give yourself permission to walk then it's then it becomes easier to tease out um when it's you know actually when you should be doing one over the other uh but yeah for people coming from uh you know from the midwest or whatever who don't have these monster climbs to practice on uh yeah they're it's probably pretty hard for them to to know if they're doing western states or hard rock or something and haven't been able to train on similar terrain it's probably hard for them to to know which one is best so uh yeah i guess i guess i would just advise you know don't be scared of walking because there's definitely going to be

a lot of times in a lot of races especially as we move slower and and as we move slower in these ultras or as we move steeper uh that it's that walking is going to be more efficacious well and to that point for the athletes that i work with that do live in more mountainous terrain i'm typically encouraging them to walk more in training so that they have the experience to feel out what that transition point is because another problem that we're always faced with in ultra marathoning is that the intensity that we're doing almost every single race at is less than the intensity at which we're going out for a normal endurance run with and so as a byproduct of that you're typically overrunning in training and you're walking a bigger proportion of the race as compared to the training that you're doing so my point with that is is that the underdeveloped skill walking is the underdeveloped skill and so you have to intentionally take steps in training to develop that to the extent that you're actually going to need them during the race and one of the ways that you do that is just encourage more walking and so you can kind of like feel out that what the right transition point for you is on a variety of different grades yeah for sure okay so we're gonna leave it at that walk more and walk more in training and be deliberate about it when you're actually going through these walk to run transitions and training because it'll help you feel it out during the race yeah don't don't be

scared of walking i think there's i i'm almost certain there's going to be listeners out there who who are who are scared of walking and and i'm just yeah it's probably good for them to hear don't be scared it's it's it's okay to do it uh in the right situation cool all right jackson we'll let you go get you back to your studies or to spring break or whatever you've got going on we're we're recording this in march in the middle of the covet 19 pandemic so who knows what's going on uh before we go though uh two things where can people reach you on social and what does your calendar look like the rest of the year yeah i mean like the covid is definitely throwing a wrench into into calendar stuff um so yeah well we'll see when races are going to be held again but um i'll if if races aren't going to be held for the next couple months i'll find some local adventure stuff um out the back door that that are hopefully fun unless they close the trails which that would be terrifying but uh hopefully they don't do that um and then i guess on social media my name is jackson brill so i can probably find me on instagram and i'm probably most active on strava pun intended brilliant all right man thanks for your time thanks for the research that you've been doing tell roger i said hi and uh you know what my vote is for what comes next yeah yeah and uh i appreciate it yeah that's my two cents it's probably worth a penny all right see you later all right okay trail runners i hope this issue of should you run or should you walk is a whole lot more clear

and the answer to it is is if you feel like you're going to go faster running run if you feel like you're going to go faster walking walk that's about how it boils down to or if you're trying to conserve yourself if you feel like you need to conserve yourself more by walking walk if you feel like you need to conserve yourself more by running run that's kind of the answer but you can't come to that answer without deliberately training it throughout the course of the training process that you have. I hope everybody takes that away from it. And Jackson was really poignant when he mentioned that there is no magic grade. There is no magic pace for everybody that will indicate when to run and when to walk a particular time or up a particular hill. That's what I really meant to say, up a particular hill. There we go. In any case, thank you all for listening.

I really appreciate it. If you want to support the podcast, you can go and give it a rating on iTunes, give it a like on iTunes, or if you happen to have a little bit of extra time, really let me know what you think. Give a review, type some words down in the comment box. I'll certainly check that out at some point, but it helps the podcast a lot when we get those likes and we get those reviews. So go ahead and do it. You can also recommend this podcast to a friend. Yeah. If you really like it, recommend it to a friend. I would appreciate it a lot. Got a lot of cool content coming up in the next several weeks. I've had to jumble it around a little bit with the COVID-19 virus kind of spreading around like wildfire. The production calendar is quite frankly, kind of all over the place, but it'll all get sorted out soon. People, this will all be behind us at one point or another. Who knows whether it's going to be weeks or months from now, but life will return back to normal until then. I appreciate everybody listening.

And eventually at some point we will see you out on the trails.