“Come on, last one!” I mutter as I hype myself up to start the last interval. It would be only 30 seconds up that hill, but those 30 seconds seemed as impossible now as winning a 24-hour race once seemed. While I had accomplished the latter just a few months before this hill workout, I knew I needed to improve my speed as an ultrarunner.
That last interval was done, and I jogged down, feeling the unique mixture of exhaustion and accomplishment that only a good speed session can deliver. As I jogged home, I reflected on how these sessions had transformed my running—not just my race times but my overall confidence and enjoyment of the sport.
Why Ultrarunners Need Speedwork
I finished my first ultramarathon without doing any structured speedwork. After all, I had only 8 months to go from not running at all to finishing a 61 km trail race. During these 8 months, getting mileage while staying injury-free was the top priority.
Finishing the race as 3rd female was a surprise. I was faster than I thought I’d be. However, I knew I needed to include regular speedwork in my ultramarathon training if I wanted to progress further and develop as an ultrarunner.
And if you’re reading this wondering if you, too, could benefit from regular speedwork in your training, then the answer is yes.
Every ultrarunner needs to include some fast running throughout a training cycle, and here’s why:
1. Speed Makes Everything Easier
When you can run fast, slower running feels more manageable. It’s simple math: if your 5k pace is 4:00 min/km, maintaining a 6:00 min/km pace for hours will feel more comfortable than if you’re already struggling to hit 6:00 min/km at your fastest. Improving your top-end speed creates more buffer for those long hours on the trail.
2. Less Time on Your Feet Means Less Stress
The ability to maintain a faster, comfortable pace doesn’t just mean better finish times – it means less overall stress on your body. When you’re faster, you:
- Spend less total time on the course
- Reduce overall impact on your joints and muscles
- Have more energy for technical sections
- Maintain better form throughout the race
3. Build Mental Toughness Through Intensity
Every speed session is a lesson in mental fortitude. Those moments when you’re pushing through your last hill repeat when your legs are burning, and your mind is screaming to stop – that’s where you build the mental strength that will carry you through the tough spots in your ultra. Speed workouts teach you to:
- Push through discomfort
- Stay focused when tired
- Build confidence in your capabilities
Building this mental toughness through speedwork is invaluable, but there’s even more to the story. As I progressed in my ultra journey, I became fascinated by how speedwork creates these improvements in our running. The science behind it reveals something surprising about one of running’s most discussed metrics: VO2 max.
VO2-max and Ultra Performance: What You Need to Know
What is VO2 max, and why should you care? Simply put, VO2-max describes how much oxygen your body can use during intense exercise. And the more oxygen your body can utilize, the more energy it can produce aerobically.
A higher VO2-max will allow you to sustain higher intensities for extended periods. Athletes with a high VO2 max will, therefore, have a higher potential to perform well in endurance events (including ultrarunning) than athletes with a lower VO2 max.
That’s why, in the past, VO2max was often considered the “gold standard” for assessing one’s potential for endurance performance, and researchers and coaches alike placed great emphasis on this single metric.
While elite athletes often have high VO2max values (for example, Kilian Jornet sports an impressive 92ml/min/kg)
, today we understand that VO2max is just one piece of the performance puzzle, and other factors like lactate threshold, biomechanics, neuromuscular efficiency, and mental toughness play crucial roles.
That is good news for those not blessed with impressive VO2max values because VO2max isn’t highly trainable, especially in experienced runners. It’s primarily determined by genetics and naturally declines with age.
However, this doesn’t mean we should skip VO2max training. While these sessions might not significantly improve your actual VO2max number, they provide crucial adaptations that make you a better ultrarunner:
1. Lactate Processing
These sessions enhance your body’s ability to process lactate, which becomes crucial during the later stages of an ultra when you need to handle tough sections while fatigued.
2. Power Output
VO2max-intensity work, especially on hills, improves your ability to recruit muscle fibers efficiently and generate force. This is particularly valuable when you must power up a steep climb 80 kilometers into your race or maintain good form on technical terrain when fatigue sets in.
3. Running Economy
These sessions improve how efficiently you use your oxygen capacity. Think of it like upgrading your car’s engine – even with the same size gas tank, you can go further by improving the engine’s efficiency.
Running economy, unlike VO2max, is highly trainable at any age.
This improvement in efficiency comes from various adaptations, such as better biomechanics, stronger muscles that can generate force more efficiently, and enhanced neuromuscular coordination (your brain and muscles working better together).
And just like two cars with the same size gas tank can travel different distances based on their engine efficiency, two runners with the same VO2 max can perform very differently based on their running economy.
For example, Runner A might need a lot of oxygen to maintain a 5:00 min/km pace, while Runner B might use significantly less oxygen to run at the same speed. This means they’re working at a lower relative effort level at that pace, which has several benefits:
- Their body is under less stress at the same speed
- They’re using less energy (both oxygen and glycogen) to maintain the pace
- They’re producing less metabolic waste
- Their muscles experience less strain
All these factors combined mean they can sustain faster paces for longer and recover more quickly. Think of it like driving two cars at 100 km/h – the more efficient car isn’t just using less fuel, it’s also putting less strain on its engine while maintaining that speed.
How to Include VO2-max Training in Your Ultra Preparation
Now that we understand why VO2-max training is valuable (even though we’re not trying to improve our actual VO2-max number) let’s look at how to include these sessions in your training.
The goal is to trigger those beneficial adaptations – improved running economy, better lactate processing, and enhanced power output – while staying healthy and maintaining our ability to handle high training volumes.
Before we dive into the workouts, a quick note about intensity. I’ll reference RPE (Rate of Perceived Exertion) throughout this article to describe how hard these sessions should feel. I’ve explained RPE in detail in an earlier article in this series, but for quick reference, here’s the scale we’ll be using:
For speedwork, we’ll work in the RPE 9-10 range. This high intensity triggers those VO2 max-range adaptations we discussed earlier. Now, let’s discuss how to incorporate these sessions into your training.
Why Hills Are Your Best Friend
While there are many ways to do VO2 max-intensity training, I advocate starting with hill work, especially for ultrarunners. Here’s why:
- Intensity Control: Hills automatically limit how hard you can push. Unlike flat intervals, where you might be tempted to sprint all-out, hills force you to work at a more controlled intensity, perfect for developing running economy and power.
- Reduced Impact: The uphill grade means less pounding on your joints than flat speedwork. This is crucial for ultrarunners who must maintain high training volumes without injury.
- Specific Strength Benefits: Hill work develops the exact strength and power you’ll need for your ultras—whether you’re up a steep climb at mile 50 or maintaining form on technical terrain when fatigue sets in.
Start Here: The 30/30 Hill Workout
My favorite speed workout – and a great introduction to VO2 max work if you are new to it – is the 30/30 hill workout.
Find a hill that is long enough for you to be able to run hard uphill for 30 seconds. Run hard uphill for 30 seconds, then recover for 30 seconds going down. You repeat this for the number of sets prescribed for that training session. How hard should these feel? Very hard. If you’re training by RPE (which you should learn), each repetition should require 10/10 effort.
How many repetitions you do in a workout depends on where you’re at in your training plan and whether you are a beginner or an experienced runner.
When I started, I would do five sets per workout. Then, I started adding more sets until I could do 15. Then, I added a second round of 30/30s after a short recovery break of around 3-5 minutes. Currently, a typical 30/30 workout looks like this:
After a warm-up of around 20 minutes, I prepare my body for the hill sprints by doing 7 rounds of strides (short accelerations that turn over the legs but are not sprinting). After a brief recovery of 5 minutes, I go into the main set of the workout, which consists of 4 sets of 10 X 30/30. Between each set of 10, I recover for 5 minutes by jogging at an easy pace. A short cooldown of around 11 minutes concludes the workout.
Please note that you shouldn’t jump into such a demanding workout. If you are a beginner runner or have never done any VO2 max work, you must gradually build up your body’s ability to handle this amount of high-intensity training.
Beyond the Hills: Other VO2-max Sessions for Ultrarunners
While 30/30 hill repeats are my favorite way to introduce (and perform) VO2max training, varying your speed training workouts provides additional benefits and keeps training interesting.
The following two workouts are a staple in my VO2max workout rotation.
Structured Speed: The 400m Workout
These can be done on the road or trail (if you fancy, even on the track). However, if you are running trails, ensure it’s not too technical. Remember, these sessions aim to develop your top-end speed so you don’t limit yourself by navigating highly technical terrain with roots, rocks, or layers of ice.
Again, I use Strides to wake up the legs after an easy warm-up. The main set is three times four sets of 400 m intervals with 45 seconds of recovery after each interval.
I love to do this workout in my local park. For the warm-up, I use the slightly undulating terrain and do Strides uphill before moving to a flat section where I can perform the 400 m repeats on a soft, non-technical path.
As with all VO2 max sessions, the effort during the intervals should be hard—or 10 out of 10 on the RPE scale.
Fartleks: Adding Play to Your Speed Training
Besides short hills and longer intervals, fartleks offer another effective way to include VO2 max training in your ultra preparation. While ‘fartlek” means speed ‘play’ in Swedish, and you can go as structured or unstructured as you want, I prefer to structure these workouts to ensure we hit the right training intensity. Here’s a simple session:
After a 15- 20-minute warm-up, the main set consists of 10-12 one-minute surges with one-minute easy jogging between each surge. Run at 9-10 on the RPE scale during the surge. The recovery minute should be an easy jog, enough to catch your breath before the next surge.
I like to do these workouts in a hilly area where I can surge up the hills as I encounter them and use the flats or downs for recovery. Not all surges will coincide with me running up a hill, but that is fine. The focus is on having fun and using the terrain as it is. Some intervals will be uphill, some downhill, and others might be a mix of both. This variety keeps the workout engaging and helps to develop the ability to change pace quickly, whether you’re uphill, downhill, or running on flats.
However, these, too, should be done on terrain that’s not too technical. The goal is to hit those high intensities that stimulate VO2 max development while staying smooth and controlled.
Another important point to stress is keeping the right intensity during these workouts.
When doing fartleks for VO2max development, be careful not to let the surges become too long or the intensity drop too low. If your “hard” sections last longer than 2-3 minutes or feel more “comfortably hard” than” truly hard, you’re drifting into threshold training territory – which, while valuable, won’t have the same VO2max training stimulus we aim for here.
What About Threshold Training?
While we’ve focused on high-intensity speedwork in this article, you might wonder about tempo runs and threshold training. Are these considered speedwork? Not exactly – and here’s why: true speedwork, like our 30/30 hill repeats, long intervals, and structured fartleks, involves running at very high intensities (RPE 9-10) for short periods.
In contrast, threshold training is performed at a “comfortably hard effort” (RPE 7-8) that you could maintain for about an hour. Think of it as the pace where you’re working hard but can still speak in short phrases.
However, just because threshold training isn’t technically speedwork doesn’t mean it’s not useful for ultrarunners. It’s an essential part of a well-rounded training program because:
- It improves your ability to run efficiently at moderate intensities
- It helps your body process lactate more effectively
- It builds endurance without the high stress of true speedwork
Think of it this way: If speedwork builds your top-end speed and power, threshold training bridges the gap between that top-end speed and your ultra-race pace. Both types of faster running serve different but complementary purposes in making you a more complete ultrarunner.
Building Speed Into Your Ultra Training
Throughout this article, we’ve explored why speedwork matters for ultrarunners, examined the science behind VO2 max training and discovered various ways to include quality speed sessions in your training.
While it might seem counterintuitive to run hard 30-second hill repeats when preparing for an event that could last 24 hours or more, these high-intensity efforts create adaptations that benefit us across all running speeds and distances.
Remember that consistency is key, as with all aspects of training. Start conservatively with one weekly speed session, focusing first on hill work before progressing to other types of VO2 max training. Pay attention to recovery, maintain your easy running base, and gradually build your workouts and intensity.
Whether aiming for your first ultra finish or improving your race times, regular speedwork will make you a more robust, efficient, and confident ultrarunner.
Just as it helped me progress from completing my first 61 km race to winning a 24-hour event, structured speed training can help you reach your ultra-running goals while adding variety and excitement to your training routine.
Note: This is part V of the Ultrarunning for Beginners series. The previous articles in this series can be found here:
Part I: So You Want to Run an Ultra-a Guide to Getting Started
Part II: Building Your Ultra-Training Foundation: From Plan to Practice
Part III: Beyond Easy Miles: Understanding Different Types of Training Runs
Part IV: Understanding Easy Runs for Ultra Distances: A Scientific and Practical Guide to Building Your Ultra Engine