I think every runner has asked themselves one of the following questions at least once: When should I run uphill? Is it worth trying to run or is it more efficient to walk? Is there a certain speed at which I should transition from running to walking and vice versa? Or, is there a certain slope gradient at which running starts to be ineffective? At what point can walking be more effective than running?
Mountain running involves an interesting combination of parameters that have an impact on the energy needed to move. Energy requirements, both walking and running, increase as you move over uneven terrain, soft surfaces or uphill.
When you run uphill, your running speed drops considerably. This is mostly because you have to add vertical velocity to horizontal velocity. The qualities to create horizontal speed and vertical speed are different, even though they are basically very similar.
When talking about flat running speed, basically 3 concepts are considered: VO2Max, lactate threshold and running economy. VO2Max (the maximum oxygen an athlete can consume while running) represents engine size, lactate threshold (the point at which lactic acid in the muscles accumulates in a greater amount than the body can handle using it as energy) represents the ability to maintain a certain speed for a certain time, and running economy (efficiency) is the body's ability to run with as little energy consumption as possible (both through cardiovascular and muscular training and through biomechanics, form and posture.)< /p>
All 3 are important for flat running but also for downhill running, but in different percentages. While running economy is one of the most important factors in endurance running (not only technique and biomechanics, but also intra and intermuscular connections + muscle adaptations) it loses importance when you start climbing, especially at a gradient of over 20%. On the other hand, VO2Max will be much more important for hill running where weight/strength is crucial and therefore leg strength or endurance is also a key quality.
Transition from walking to running. Basic information
When it comes to locomotion, walking usually requires less energy than running at speeds below 2m/s (or about 08:20 minutes per kilometer) and can be distinguished by a lack of flight phase . This means that one foot is always on the ground at any given time. Running is usually more economical at higher speeds because tendons are extremely efficient and have the ability to act like springs - storing and releasing energy. Running can be visually distinguished from walking by identifying a flight phase or a moment when both legs are in the air. However, if you run at a low enough speed, the flying phase can disappear. This type of running is called "grounded running".
Usually, a person will naturally transition from walking to running at an optimal metabolic rate (about 2 m/s or 08:30 min/km), but this rate can vary depending on body size.< /p>
The easiest way to feel this transition phase is to run on a treadmill. The speed of the belt will gradually increase and you will start running when you feel that walking is no longer comfortable.
What happens when we run uphill?
Running up steep slopes is never easy, but researchers at the University of Colorado Boulder have discovered a series of slope gradients that would allow an athlete to climb the fastest.
This university is home to one of the steepest running tracks in the world, capable of reaching slopes of 45 degrees (100% incline).
The University's biomechanics department is spectacular and has been pushed to the forefront of the scientific community largely through the research of Professor Rodger Kram.
Whether running or walking, slopes between 20 and 35 degrees require almost the same amount of energy to climb a hill at the same vertical speed - Rodger Kram. Interesting, right? Who would have thought of that?
The extreme slopes of vertical competitions inspired Kram and his colleagues to design a specialized treadmill that can reach inclines of up to 45 degrees. Standard treadmills in gyms reach a maximum incline of about 9 degrees, while a typical black diamond ski slope reaches about 25 degrees.
Kram summarized the findings with an analogy: Imagine you're standing in Colorado at a trailhead where the base elevation is 2,740m. Your friend challenges you to run to the top of the mountain, which rises to 3740m, which is 1000 positive elevation. There are several different routes to the top. All are quite steep and some are extremely steep. One route has an average gradient of 10 degrees (17.6%) and the sign says it has a 5.8km long. A second route averages 30 degrees, (57.7%) but is only 2km long. A third route averages 40 degrees (85.9%), but is only 1.6km long. To get to the top the fastest, which route should you choose and should you walk or run?
Based on research, it has been found that choosing the second route (30 degrees) and going as fast as you can in your aerobic capacity is the fastest way to get to the top as quickly as possible.
The study focused on a vertical speed of just over 1 step per second, a pace that high-level athletes could sustain aerobically during testing. At that speed, walking used about nine percent less energy than running. So intermediate athletes can climb very steep climbs faster by walking rather than running.
The study examined 15 competitive mountain runners as they ran and walked on a treadmill at seven different angles ranging from 9 to 39 degrees. The speed of the treadmill was set so that the vertical rate of ascent was the same. Thus, treadmill speeds were slower at steeper angles. Athletes were unable to balance at angles greater than 40 degrees, suggesting a natural limit to the feasible slope for a VK competition.
Very few people walk or run on such steep slopes, but by going to the extremes, we broaden our horizons and investigate the limits of human performance," Kram said.
The results of this study also indicate that you can still get a good aerobic workout simply by walking very steep slopes.
When is it recommended to run on the slopes and when to walk?
In the same study, it was found that at slopes above 15.8 degrees, it was more than 8% more efficient for athletes to walk. Walking conserved a lot of energy compared to running at the same speed on these extreme slopes. An explanation for this could be that in these steep guards, even though the participants were trained to run, one foot was always on the ground, like walking, but at a faster frequency and shorter stride length than walking. The typical mechanics associated with running and walking are not relevant when running uphill. Running on very steep slopes does not have a typical flight phase like running on flat ground. This means that the tendons are not loaded as they are during flat running and it is not an efficient means of locomotion.
In general, walking is recommended on slopes greater than or equal to 15 degrees (27%), especially when moving at speeds lower than the walking transition speed (08:30min/km). Running will be more efficient when moving at a higher speed.
But it's not just about the metabolic economy of running.
The transition point from running to walking should be based on gradient, speed, perceived exertion, distance and strategy. It is always a combination of the 5 parameters above.
Too often, runners and coaches focus on running economy (the rate at which you consume oxygen at a given speed) as a determinant of improvement and a predictor of performance. While running economy is important, it is also important to remember that long-distance running performance is not as related to power and aerobic economy as other endurance events (such as 5k, 10k, or vertical races ). Localized neuromuscular fatigue, supraspinal input (the brain sending signals to the rest of the body), muscle damage, and a host of other indicators outside of the cardiovascular system will also impact performance. Some can have a much bigger impact than running economy.
As for the answer to the question "When should I run uphill?", it's this: It's multifactorial. The point at which walking is more economical than running (you consume less oxygen walking at the same speed as running) will differ from person to person depending on the conditions. And also fatigue, race length, potential muscle injuries and other strategic considerations must be taken into account. It may seem economical and you can feel good on a climb at the beginning of a race, but along the way, due to accumulated fatigue and sometimes lack of energy, you cannot maintain a certain pace throughout the race.
Probably many of the amateur runners have never run uphill, they transition to walking as soon as they reach the base of the climb. Many do this out of fear of running out of energy or simply because they have never trained for it. But given that in a trail race most of the time is spent uphill, any small improvement will be noticeable.
How can you train to improve your uphill speed?
Focus on cardiovascular and respiratory capacity. VO2Max is the main limiting factor why you can't run uphill or why you tire very quickly when you try to do it. how do you do that Through training with high intensity intervals, preferably on a slope. Don't have a slope? You can successfully use a treadmill. Don't have tape? It simply integrates flat intensity interval training.
I introduce strength exercises into your training routine that can help you improve your running economy and endurance in both walking and running. Some simple examples: Lunges, Step-Ups, Split Squats, Single Leg Squats.
Practice walking in training. Trying to run every climb can be inefficient, especially in ultramarathon races with long climbs and a lot of difference in level. Walking should be part of your race strategy. Like nutrition, hydration or equipment, it should be simulated in training. I'm one of those runners who prefers walking to running on the longer or slightly steeper climbs. There were not a few instances where I overtook runners who were running uphill with a higher energy consumption and slower speed than I was walking. Thus, you also save quite a lot of energy for the descents and the flat sections.
Dose your intensity based on perceived exertion (RPE). As I said above, the transition from walking to running and vice versa is affected by a number of factors. Walk when the perceived exertion becomes too much and run when you can keep the RPE in the desired range. It's simple, but it's not easy. That's why you need to simulate and test each strategy separately. Effort in an ultramarathon should be maintained at 6/10 to finish well, while in a vertical kilometer or race of up to two hours it can be taken to an RPE of 9/10.
Take into account the cardiovascular effort, the respiratory effort, the muscular effort but also for how long you have to maintain that effort.
If you're indecisive and don't know whether to run or walk a climb, walk if the run or isolated climb is longer and run if the run/climb is shorter. With shorter climbs and/or runs, you can take more risk and maintain a higher effort on the climb, knowing there's a descent close enough to recover from.
If you want to see even more clearly where your weak points are in terms of climbing, I propose an interesting test.
This test was proposed by a successful Spanish runner and coach. His name is Pablo Villalobos, so you know who you're cursing during the test.
It calculated the relationship between positive level difference accumulation and flat running speed. He calls this concept kilometer effort, or as the people at Coros call it, Effort Pace.
This concept is similar to the same one used by ITRA to calculate each runner's coefficient, applying a linear relationship between kilometers and accumulated positive elevation (100m vertical = 1km linear).
The test consists of a 21-minute treadmill run, starting at an intensity below your personal threshold, your seminar pace or 10k on the flat.
Increase the incline by 1% and decrease the speed every minute for 21 minutes without a warm-up routine. This way you can identify at which speed and on which slope gradient you feel more efficient in running. It's a very good test to identify the point at which you reach the threshold in the climb and thus establish a race strategy as correct as possible for the following competitions.
If you don't have a treadmill that goes up to 20% incline you can only go up to 15%, you will collect enough data to identify potential weak points.