How to improve your running endurance?

There is both good news and bad news in the answer to this question.

The good news is that our bodies have been programmed for thousands of years to adapt gradually to a change in 'physical load' and thus improve our endurance. Running a marathon seems like a very ambitious goal for many people, until one day, with a lot of training, you manage to do it and you're surprised by your body's ability to adapt. And without going as far as a marathon, our body will always adapt to a repeated physical load and will gradually become more enduring. It will tire less quickly and will be able to 'endure' a sustained physical load, an effort over a longer and longer period of time as it keeps training.

When I ran my first half-marathon, I thought the distance was already quite long, and during the race I even said to a friend with whom I was running the marathon: 'just imagine, for a marathon, you'd have to run a second half-marathon now'. It seemed really difficult and long. I couldn't imagine that a few years later, after having already run a dozen marathons, I would one day start a marathon during a long-distance triathlon (Ironman format) after more than 7 hours of effort in swimming and then on the bike. With training and motivation, anything is possible, thanks to the extraordinary ability of our bodies to adapt and our minds to prepare us to become resilient.

The bad news, or the other side of the coin if you like, is that it requires effort (with some training sessions being particularly demanding and difficult), resilience and patience over time, and discipline to place and carry out the training sessions. You don't always feel like it every day. Neither are the weather conditions, and it sometimes takes a lot of determination, especially in the morning, to get up and go out anyway. It takes a certain amount of courage, but the physical fitness that comes gradually with training also has many advantages, such as giving us a much higher level of energy on a daily basis.

Improving your endurance is therefore beneficial not only in sport but also in everyday life.
So how can you improve your endurance, and what exactly is endurance?

What is endurance?

Before going into detail about how to improve your running endurance, it's important to define what endurance is.

Endurance is our ability, thanks to the beneficial effects of training, to resist fatigue better and better when we make a sustained physical effort. This ability to resist fatigue is both physical and psychological. In this article, we're going to talk mainly about the physical capacity of the human body, but the capacity for psychological resistance is just as important, especially when we experience difficult moments. There's an expression that I've heard ultra-distance runners use to describe these difficult moments. They talk about moments when they find themselves in the 'pain cave'. This expression is colourful enough to make you realise that it's not the best part of the race.

To go back to the concept of endurance, it can also be defined as our body's ability to renew the energy it consumes over time during exercise. And what training helps us to do is to improve our 'energy' output, like an engine. And our engine is both our cardiovascular system and our muscle mass (the third ingredient being our mind, our motivation).
To better understand the concepts of endurance and energy efficiency, it's important to introduce a number of concepts, including VO2 max.

VO2 max

Our VO2 max is our body's maximum capacity to use the oxygen we breathe to release the energy our body needs to sustain a prolonged physical effort such as running. If we try to run faster and faster, there will be a moment, depending on our individual abilities and level of training, when our body reaches its maximum capacity to consume oxygen. At that point, we have reached our VO2 max and our maximum aerobic speed or MAS.

Economy of movement or running form

The second key concept is that of economy of movement or running form. An efficient runner is one who expends less energy for a given distance at a given speed. If two athletes have the same MAS but one has a more efficient running technique, that runner will have more endurance. By generating fewer parasitic movements and converting his energy into speed more efficiently, he will be able to last longer. It's a bit like calculating energy consumption per kilometre at a given speed. Both runners start with the same reservoir of energy, but the most efficient runner will consume less energy per kilometre at the same speed and will therefore last longer (assuming both runners eat and rehydrate in an appropriate and comparable manner).

Recovery

The third concept is recovery. Increasing your VO2 max and acquiring a highly efficient running technique are not enough to become and remain an enduring runner. Without adequate recovery, injury or a drop in performance is guaranteed. Simply because our body needs this recovery time to regenerate itself. The optimum recovery time will depend on the intensity and duration of each session. It could be 12, 24 or even 48 hours. After particularly demanding events such as a Marathon or an Ironman, recovery will not be counted in days but in weeks, and the resumption of training will also need to be very gradual.

To become more enduring, we need to work on several fronts, namely improving our VO2 max, developing an economical and efficient running technique and constantly ensuring that we recover well.

What kind of training programme is necessary to improve our endurance?

There are, of course, a plethora of training programmes to choose from, depending on the race distance you are aiming for, from 5km to 10km, half-marathons, marathons and ultra or trail running, from short distances (under 20-25km) to medium distances (between 20-25km and 40-50km) to long ultra-trail distances (over a marathon).
However, there are certain constants or key points to take into account in your training programme if you want to improve your endurance. We've listed ten of them below:

1. Run three times a week

The improvement in VO2 Max increases with the frequency of training. This is particularly true up to a frequency of 3 days a week. Beyond a weekly frequency of 3 sessions, you can still gain in endurance, but the gains diminish. Beware, too, of the risk of overtraining after three or four days. You should increase the frequency very gradually, always listening to your body to avoid overtraining leading to injury. It should also be noted that below 2 days training per week, there is generally no significant increase in VO2 max. For beginners or those returning to running after a long break, here are a few more key tips to follow to avoid injury.

An additional point of attention for beginners: the risk of injury increases if you train more than 3 days a week and the duration of your sessions exceeds 30 minutes. So if you're just starting to train in running, it's advisable not to exceed 1h30 of cumulative running per week and 30 min per session for at least a month. It is also advisable to start strength training at the same time.

2. Include a high-intensity interval training session

These sessions have the greatest impact on aerobic improvement. On the other hand, they are demanding. They 'hurt' and the last few repetitions are increasingly difficult. These sessions include a 10-15 minute warm-up at a moderate pace, followed by high-intensity interval repetitions, such as 30sec/30sec, 1min/1min, 45sec/15sec or potentially 400m/800m track repetitions, etc., each time repeating a sustained effort at high speed followed by a recovery at low speed. It is these repetitions that make up the intervals and split the session into a series of fast and then slow runs, hence the name interval training. The end of the session should include a gradual return to calm at low speed. Depending on the intensity and duration of the interval training session, you should allow adequate recovery time. For example, you shouldn't plan two high-intensity sessions on two consecutive days if you're planning two high-intensity sessions during the week.

3. Plan a weekly long run

To improve our endurance, we also need to get our body used to running for long periods. This is the role of the weekly long run. Unlike the interval training session, this one should be run at a lower intensity than the target race pace. For example, if you're preparing for a marathon, the long session should be run at between 10% and 20% slower than your target marathon pace. Another way of defining the target running intensity for a long run is in relation to your MAS (maximum aerobic speed) or MHR (maximum heart rate). The target is to run at an intensity equivalent to :
- 65-70% of MAS
- 70-75% of MHR
Ideally, there should be no heart rate drift at the end of the long session. The heart rate should be the same as at the start of the race (after the warm-up).

The reason why a long run is necessary to improve endurance is that it allows the body to give priority to using lipids as source of energy. For long sessions, our body needs energy either from carbohydrates or from fats (lipid). The largest reserve of energy in the body is fat. A long run causes the body to dip into this fat or lipid reserve. This goes hand in hand with a lipid-rich diet.

One last point on the long run, it should be longer than an hour and last roughly between 1h15 and 2h30 max (for marathon training).

4. Plan a low-to-moderate intensity recovery session

This third type of session is the weekly recovery session. It's a run at a low-to-moderate intensity. You should be able to maintain a conversation during the session. The target pace range is around 55-70% of MHR or 50-65% of MAS. For beginners, this session can last between 30 and 40 minutes, while more experienced runners can aim for between 45 minutes and an hour. This recovery session can be scheduled after a high-intensity session or after a rest day. It promotes blood circulation and eliminates metabolic waste from the muscles. It also helps to prevent muscle soreness and maintain muscle flexibility. It's a form of active recovery. Alternatively, a session of swimming, cycling or yoga/stretching can also be programmed to vary the pleasures or in addition to three running sessions.

5. Increase the distance gradually and according to your goal

As we're talking here about a programme of at least three weekly sessions, be careful to increase the distance covered per week gradually. An easy rule to remember is not to increase the weekly distance covered by more than 10% per week. If you are on a pace of 30 kms covered in three sessions, you should take care not to programme more than 33 kms the following week. This means that for three sessions, your sessions should increase by an average of no more than 1 km per session. This gradual approach is key to giving our bodies time to adapt (muscles, ligaments, tendons and our cardio-muscular system). It also helps improve our performance and, above all, reduces the risk of overtraining and thus preventing injury. The maximum total distance of a weekly training plan will depend on the objective being pursued. To give you an idea, depending on the race you're preparing for, the maximum cumulative distance outside of very experienced runners should be between 20 and 40 kms for a 10K, 40 and 60 kms for a half-marathon and between 60 and 100kms for a marathon. Please note: this is a maximum or peak training distance over a week and not an average over the duration of the training plan.

6. Improve your running technique

Running technique is the key to becoming an energy-efficient runner. Here are a few principles to bear in mind if you want to improve your efficiency and adopt a good running technique:
- an upright posture (a straight back and eyes straight ahead, not on the ground),
- relaxed shoulders and hands
- head-shoulders-hip alignment
- a light, fluid stride without excessive arm movement
- a fairly high cadence of 160 to 180 steps per minute
- land your feet in the middle or front of the foot, if possible, rather than on the back of your heels*.
- breathe regularly and deeply to maximise oxygen intake.

* Caution: if you try to correct your stride, it should be very gradual, starting with a correction of a few minutes per max session and then lengthening the correction very gradually. If you don't give your body time to adapt, injury is almost certain, particularly to the tendons.

7. Core strengthening for a stable foundation

Strengthening your core, particularly the abdominal muscles and the backbone, is key. It will help to improve your posture, balance, running economy and endurance. Your pelvis and torso will be more stable, allowing energy to be transferred efficiently from your upper body to your lower body. You'll avoid any compensatory movements that can over time have an impact on your lower back, hips or knees. Finally, you'll delay the onset of fatigue and be able to maintain efficient running mechanics for longer. Strengthened abdominal muscles and back muscles are a key component of an economical and effective running technique.

7. Watch your nutrition and hydration

It's obvious: proper nutrition is essential if you want to train effectively and improve your endurance.
A balanced diet will provide you with the nutrients (carbohydrates, fats, proteins) you need for your training sessions, so you can replenish your energy reserves.
Good hydration is essential for maintaining your body's water balance and regulating its temperature during exercise via the sweating process. It also enables nutrients to be transported and metabolic waste to be eliminated. Conversely, the onset of dehydration is synonymous with reduced performance, greater fatigue and an increased risk of injury.

9. Plan adequate recovery & rely on quality sleep

Recovery and sleep allow the body to repair and regenerate itself. Muscle tissue damaged (micro-tears) during exercise has time to repair itself. Regeneration is not just physical. It is also mental. Rest helps to restore cognitive functions such as concentration and coordination, which are key ingredients in athletic performance. It also plays a major role in maintaining motivation and the energy you need to train over the long term.
On the basis of training 3 or 4 sessions a week, it is advisable to plan at least one or two days of total recovery (a day of rest with no sporting activity) and several days of active recovery (sessions of low-intensity physical activity: light running, swimming, cycling, yoga, walking, etc.).

10. Be patient

Even if you follow all the advice above, improving your endurance will take time. It will be very gradual. You will need to be patient. Improvement will take months or even years rather than just a few weeks. Between my first marathon and my best marathon, I was able to improve my time by almost 50 minutes. That's quite a significant improvement for an amateur runner. But it took several years, at the rate of two marathons a year, before I achieved this gain in performance and improved my endurance.
If you're a beginner runner, if you don't do any other endurance sport regularly and if you're already tempted by long-distance running, you'll need to be patient and plan at least 6 months to a year before taking part in a half-marathon and at least a year before doing a marathon.

With patience and diligence, the effort will eventually pay off and you'll become more resistant. The icing on the cake is that you'll have more energy not only during your running sessions but also in everyday life. This hard-won endurance will benefit you far beyond your sporting activities. And it is ultimately in the level of energy we get in everyday life that the greatest benefit of improved endurance lies.