What variables influence ultramarathon performance ?
There have been a number of studies on this which are listed in the bottom of the notes to this video.
Lets look at the main findings of these studies
1)“ Effects of training and anthropometric factors on marathon and 100 km ultramarathon race performance”
Beat Knechtle , 2015, Open Access Journal of Sports Medicine
Performance was correlated to volume and training pace ( but greater correlation to volume ) Interestingly they also found lower body fat also helped but once it got below 15% performance could be predicted solely on the basis of training metrics
2) Performance Determinants in Trail-Running Races of Different Distances
Pastor et al, 2022 , International Journal of Sports Physiology and Performance
Performance in SHORT races ( < 50km ) was explained by maximal oxygen uptake and lipid utilization at 10 km/h
. Performance in MEDIUM races ( 50-100km ) was determined by maximal oxygen uptake, maximal isometric strength, and body fat percentage
. in long races > 100km, velocity at Vo2 max was the only factor that correlated to performance
3) “Physiological Determinants of Ultramarathon Trail-Running Performance”
Coates et al ,2021 International Journal of Sports Physiology and Performance
They found velocity at V02 max was a good predictor of 50km performance , in 80km race less so and in 160km none of the determinants measured ( running history, aerobic fitness, running economy, body mass loss, hematocrit alterations, age, and cardiovascular health ) were correlated to performace
4) Performance Factors in a Mountain Ultramarathon
Balducci et al International Journal of Sports Medicine 2015
Performance time was correlated with Maximal aerobic speed , fraction of MAS (FMAS) sustained , knee extensor force.
5) “Predictors of Athlete’s Performance in Ultra-Endurance Mountain Races”
Pedro Belinchón-deMiguel , 2021 , Int J Environmental Res search Public Health
Ultra-endurance mountain athletes competing in longer races (>90 km) have more experience and follow harder training schedules compared with athletes competing in shorter distances.
For races between 45 and 90 km, training intensity and volume were key predictors of performance.
6) “Different Predictor Variables for Women and Men in Ultra-Marathon Running—The Wellington Urban Ultramarathon 2018”
Emma O’Loughlin, 2019 , Int J Environmental Res search Public Health
For women, the volume of running during training per week (km) and personal best time (PBT) in 5 km, 10 km, and half-marathon (min) were all associated with race time. For men, age, body mass index (BMI), years running, running speed during training (min/km), marathon PBT, and 5 km PBT (min) were all associated with race time
7 ) “Ultra Trail Performance is Differently Predicted by Endurance Variables in Men and Women”
Ignacio Martinez-Navarro , Int J Sports Med 2022
“peak speed and maximal fat oxidation together were able to predict 66% of male performance; while peak oxygen uptake was the only statistically significant variable explaining 69% of the variation in women’s race time”
8)“Predictor Variables for A 100-km Race Time in Male Ultra-Marathoners”
Beat Knechtle, Jounral of Perceptual and Motor Skills, 2010
showed that training speed , mean weekly running kilometers , and age had the best correlations for a 100-km race .
9) VO2max and Velocity at VO2max Play a Role in Ultradistance Trail-Running Performance
Frederic Sabater-Pastor , International Journal of Sports Physiology and Performance, 2023
velocity at VO2max predicted 65% of the variability in performance while a model combining VO2max and cost of running combined predicted 62% of the variability
10 Downhill Sections Are Crucial for Performance in Trail Running Ultramarathons—A Pacing Strategy Analysis
Matteo Genitrini et al , Journal of Functional Morphology and Kinesiology, 2022
“ running downhill sections at higher relative speeds, most likely due to less accentuated fatigue effects, as well as minimizing performance decrease in the later race stages in downhill sections, appears to be a hallmark of the better finishers.”
11) “Multidisciplinary Analysis of Differences Between Finisher and Non-finisher Ultra-Endurance Mountain Athletes”
Belinchón-deMiguel Pedro et al , JOURNAL=Frontiers in Physiology, 2019
“Finishers presented lower systolic blood pressure, weight, body mass index, half marathon time and fluid intake before competition day compared to non-finishers. In addition, body mass index, pre-race hydration, and performance in lower distance races were predictors of performance in these ultra-endurance mountain races. ”
So some common themes amongst all of that are
- training volume and intenisty
- velocity VO2 max
- muscle strength of quads to tolerate eccentric load of downhill running
- performance in shorter races
Also mentioned were
- body fat ( although it seems once you get to a certain level having less is not predictive of performance )
- Fat Metabolism
- Maximal Aerobic Speed and % of that one can sustain
A few studies mentioned slight differences between predictive factors between men and women ( and we will discuss in detail the differences between the sexes and how that effects training in another video )
It should be noted that in many of these studies, the factors discussed could only account for approx 60% of ultramarathon performance. The remaining 40% are as yet unknown and the longer the race the less correlation the assessed fitness variables had on performance prediction.
There were also a number of factors the studies didnt mention including
- amount of vertical per week
- lactate threshold
- aerobic threshold
- how long the long run is and how many long runs were done
- how training intensity was distributed throughout the week
So what does all this mean in terms of how we should approach training plans for ultramarathon athletes ?
The two most common and highly correlated factors were velocity VO2 max and training volume. So you could argue that developing velocity at VO2 max should be a key focus. But before we rush out and set our athletes VO2max workouts I think it’s important to step back and look at the bigger picture.
What are the fitness attributes that a good ultramarathon runner has?
- Fatigue resistance. This is a subject of ongoing research but it can be defined as how much your physiological metrics deteriorate throughout a race. The less they deteriorate the less you slow down later in a race.
- Velocity at < 90% of Threshold. Ultramarathons are run at intensities less than 90% of Threshold often 70-80%. An athlete with a faster velocity at that intensity will perform better
- Good eccentric strength in knee extensors to handle the downhill running.
- Good technical skills ( if race has technical trails )
- A stomach that can handle 40+grams of carbs per hour for the duration of the race
Of course there are mental attributes an ultra runner should have but if we just look at the physical characteristics if you have those five you are going to perform well.
So now if we go back to the studies you will note that few of them mentioned what one might deem as the optimal physical characteristics of an ultra runner.
The traditional fitness metrics used in studies may not assess the attributes needed to perform well in Ultras. We are looking at Ultramarathons through the lens that we look at shorter races and maybe we need a different lens.
A good example of this is running economy. In road races running economy is a hugely important factor but in ultras it isn’t. Why? The majority of tests on running economy are performed on treadmills and although we see a good correlation between flat and uphill running economy, running on a treadmill is not running on a trail. There have been some studies that show that ultra runners sacrifice running economy to preserve muscle damage and other studies that running economy actually improves after an ultra.
The relationship between running economy on a treadmill and running economy on trails is not well established so whilst running economy as measured on a treadmill may not have much relationship to ultra performance, running economy on trails might do.
This doesnt mean we just ignore the studies , they do help paint a picture but it’s an incomplete picture
Lets look at the picture they do paint
1. Velocity VO2 max and VO2 max.
These can be improved two main ways – high intensity workouts and or lots of easy running. So this links to higher volume helping performance. Ie if doing high volume then it’s likely you will be increasing your VO2 max.
We will talk in detail about VO2 max and how it can be trained in another video.
- Training Volume and intensity
It comes as no surprise that more running helps. There is a reason that even 1500m, 3000m track runners run relatively high mileage. Lots of easy aerobic running helps and the same applies to Ultras. How much mileage and the balance of easy runs to harder runs we will talk about in another video
- Muscle strength of Knee extensors
One may argue strength training could be an important part of an ultra runner’s training based on this. However assessment of knee extensors is typically done with the knee at 90 degrees and measuring the peak isometric force one can produce over a few seconds. Clearly, one’s ability to produce a maximal 2-second effort sitting on a machine with leg bent to 90 degrees is quite dissimilar to the load on the knee extensors in running ( in running the knee is bent to around 20 degrees at foot strike and 40 degrees at mid stance ). Yet there was still some correlation between knee extensor strength and performance. Assessing knee strength in a way that is more reflective of the demands of an ultra might show an even greater correlation to performance
- Performance in shorter races
We know that velocity VO2max, training volume and intensity are significant predictors of performance in shorter races and they are also partly predict performance in ultras. Hence it makes sense that how fast you are in shorter races partly predicts how fast you are in ultras. The important thing to remember here is shorter races ( and all the other factors ) only partly predict performance in ultras. If we could account for 80+% of ultra performance one could argue that training for ultras should be similar to training for shorter races but given using traditional fitness metrics we can only account for around 60% ( at best ) of ultra performance it suggests that training for ultras although having many similarities should be different to training for shorter races.
So where does that leave us in terms of what are the training goals when training ultra runners? We will discuss that in part 2
Lets go back to our ideal fitness attributes an ultra runner would have and look at how we might train them
- Fatigue Resistance
If we test someone’s V02max or Threshold at the start of a race and then test again after several hours of running there will be a decline in the numbers. How much decline is a measure of one’s fatigue resistance.
The less the drop in fitness metrics , the greater ones fatigue resistance and the less you slow down later in your race.
How do we develop greater fatigue resistance ?
Increasing fatigue resistance is very much part of the art of coaching rather than the science. A lot of the studies into fatigue resistance look at the ability of cyclists to sprint at the end of a race or runners to kick for home. The bigger the kick the athlete has the higher their fatigue resistance must be. However, in an ultra it is more about slowing down the least not unleashing a kick for the line. How exactly we train to slow down as little as possible is the million dollar question. With so many aspects that go into ultra running, developing fatigue resistance in ultras is still a topic for debate with no clear evidence on the best way to improve it.
If we want to increase VO2 max we have very good evidence on the best way to do this , same goes for lactate threshold. But increasing ultra fatigue resistance is a case where coaches are driving the knowledge further rather than science guiding our coaching practice.
From a coaching perspective I believe there are a number of training methods that will improve fatigue resistance
1.1 . Volume .
Its no co-incidence that elites tend to run more miles than non elites and that volume does feature as a predictor of ultra performance. How much volume an athlete can handle and how that volume should be made up we will discuss in future videos.
1.2 . Density of training
Volume alone is not sufficient to build specific ultra endurance, volume density must be considered . To understand this take these two examples
Two athletes with the same fitness start a training program both running 84km a week
Athlete 1
Monday – easy 12km
Tuesday – Speed session 12km
Wednesday – easy 12km
Thursday – easy 12km
Friday – hard hills session 12km
Saturday – easy 6km
Sunday – 18km long run
Athlete 2
Monday -day off
Tuesday – Speed session 12km
Wednesday – easy 10km
Thursday -day off
Friday – hard hills session 12km in the evening
Saturday – 30km long run – early morning
Sunday -20km easy
Even though both athletes are running the same distance and same intensity it’s not hard to see that Athlete 2’s training is likely to have them far better prepared for an ultra than Athlete 1.
The combination of Friday Saturday Sunday means a higher training load and greater training adaption.
How the weekly volume is distributed throughout the week can make a big difference to the training response.
2. Velocity at < 90% Threshold.
It makes sense that if two runners are running at 80% of their threshold and one runner is running at a faster speed then they will perform better in races ( all else being equal )
So how do we improve our pace at slower intensities ?
2.2. Volume
Most of our running is performed at low intensity but a higher volume of low intensity running will improve both our slower speed and our faster speed. A lot of low intensity running improves our base aerobic fitness , increases mitochondria density and function which improves our ability to covert the food we eat into energy , and also our ability to re-use lactate for energy. Hence we improve both our fast and slow speeds.
You can think of this as pushing our fitness up from below.
2.3 Speed work
Speed work lifts our fitness up from above. Improving ones 5km or 10km speed means a corresponding increase in ones marathon and longer speed.
The exact type of speed work we will discuss in detail later.
3. Good eccentric strength in knee extensors to handle the downhill running.
There are three main methods of developing eccentric strength in the legs
- More volume – we keep coming back to more volume as it has so many benefits
- Downhill running – the more downhill runing we do the better conditoined our legs become at withstanding the loads placed on them running downill . There is a whole video just on downhill running later in the course to discuss how best to implement downhill running into a training plan
- Strength exercises – A well-designed strength program can significantly improve the legs ability to tolerate high eccentric loads Especially if one does not have access to suitable hills in training. Exercises that focus on quads and eccentric loading are optimal ( with the caveat that less specific exercises may be needed to begin with to condition the legs for the harder eccentric exercises)
4 Good technical skills ( if race has technical trails )
Speed on technical terrain doesnt come with fitness. Take a 2:10 road marathoner and race him against someone like Kilian Jornet down a steep technical descent and the road marathoner will come a distance second.
Technical descending is a skill and like all skills take practice to improve.
Coaches need to determine the technical demands of a race, the current skill level of their athlete and the training environment the athlete has to train in and then devise training sessions to improve technical skills.
Hiking uphill is also a skill and if the race is likely to include a lot of hiking this should be a key part of the training plan.
5. A stomach that can handle 40+grams of carbs per hour for the duration of the race
A forgotten part of a training program is testing nutrition and training ones stomach. If you cant fuel your body it doesnt matter how fit you are you wont be able to perform to the level of your fitness. Stomach issues make up a large percentage of the reasons given for DNF’s or poor performances.
Coaches need to implement nutrition strategies in long runs to test what calories sources an athletes stomach can tolerate well and to train the athlete’s stomach – the nutrition section will cover how to do this in detail
Key Take Homes
Factors that influence ultra marathon performance are not well defined and the longer the race goes the less we can say for sure what factors are important
Factors that studies say are likely important are , VO2 max, velocity VO2 max, training volume , training intensity , knee strength , speeds at shorter distances , greater ability to run downhill when fatigued, maximal aerobic speed
Other factors that are likely more important include , fatigue resistance, speed at < 90% threshold , strong quads to handle large eccentric loads, good technical skills , well training stomach.