Tempo Hill Intervals: the best all round endurance hill running session?

Tempo Hill Interval Training

If you’re looking for a hill workout to develop aerobic and anaerobic endurance, muscular endurance, fatigue resistance and your lactate threshold, then you can’t get much better than tempo hill intervals.

Tempo hill intervals are one of my favourite hill sessions. In fact, they’re my go to hill workout in the build up to key endurance races.

Key benefits of Tempo Hill Intervals

  • Develops both lactate threshold and VO2max
  • Improves strength and muscular endurance
  • Enhances aerobic and anaerobic endurance
  • Can tolerate increased muscle acidity
  • Improved fatigue resistance

Whilst the main focus of this session is aerobic endurance, there’s actually a strong anaerobic component, making this one of the best all round hill sessions for endurance runners.

In this article, we’ll take a look at the training benefits of tempo hill intervals. And look at how I’ve used this key session in the build up to races.

So, what are tempo hills?

The simplest way to think of Tempo hills is, as an over/under version of hill training. If you’re unfamiliar with over/under training, it’s a type of interval training, where we alternate between running at intensities slightly above, and slightly below, lactate threshold intensity.

With tempo hills the over part (above lactate threshold intensity) is the uphill, and the under part (below lactate threshold intensity) is the downhill.

So with tempo hills we’re controlling the intensity of the downhill recovery as well as the uphill effort. By doing this we maintain a significantly higher average work rate, throughout the whole workout. In fact, the average intensity is very close to a tempo or threshold run. This works particularly well with short hills (~20-60seconds duration), run on a moderately steep incline (~4-6% gradient).

The recoveries are significantly shorter

The real difference with tempo hills is the recoveries…they’re significantly reduced.

Here, the recoveries should only take around 15-25% longer than the uphill section. As an example, if you’re running the uphill in 30seconds, then the downhill is run in 35-38seconds. The idea is that you are getting the minimum recovery period needed in order for you to maintain a good (above lactate threshold) pace on the up hills. In comparison; with short hill repeats, the recovery time can be more than twice the length of the effort. 

In this way, the average intensity of the combined uphill and downhill, is close to lactate threshold intensity. Making these ideal for lactate threshold training. The uphills also develop aerobic capacity as well as strength and muscular endurance.

Whilst this recovery sounds quite challenging, you do have the the assistance of gravity. And the gradient can have a significant impact – steeper gradients make the uphill more challenging but make it easier to run a fast descent.

How do tempo hills differ from Kenyan hills?

The main difference with tempo hills is the greater variation in intensity, between the uphill effort and the downhill recovery. Kenyan hills are more about maintaining a steady pace on both the uphill and downhill section.

With tempo hills we push the uphill section like you would during track based intervals. Then on the recovery, we reduce the intensity just enough to maintain the work rate of the uphills.

In this sense tempo hills are more like an interval session. And specifically an over/under interval session.

As your conditioning improves, you’ll find you can start to increase the intensity of uphills. And with consistent training, it’s possible to push the uphills at close to VO2max intensity, whilst running the downhills at just below threshold intensity. This allows you to maintain an average intensity that is close to threshold intensity.

How to run tempo hills

As always, start with a good warm up including mobility exercises, dynamic stretching, strides, accelerations and ideally some running drills.

Once fully warmed up you’re ready to start. All you need now is a hill with a moderate gradient (ideally 4-6%) and the willingness to push through the inevitable build up of fatigue.

For the tempo hills, run the hills continuously as either one continuous session (e.g. 20-30minutes), or broken into smaller interval blocks e.g. 2-3 x 10minutes of hills, separated by 3-5mins of easy running.

Alternatively you can run a set number of intervals rather than by time. As an example, sometimes I may run these as 3 sets of 10 x 30sec hills.

The intensity of the uphill should vary depending on your training focus, the length of the hill, your training experience and current fitness/conditioning level.

For longer hill tempos (50-60seconds duration – I wouldn’t go longer than this with this session!), the intensity for the uphill section should be in the region of 5/10k intensity (as a minimum).

Shorter hills allow a greater intensity

With shorter hills this intensity can be increased. The key is to find an intensity that you can sustain across all the hills.

When I run these, I prefer to use shorter hills that take ~30-35secs to run up. This allows a higher intensity on the uphills. It also means the length of the recovery is shorter (35-40secs, compared with 60-65secs for a longer 55-60sec hill), which helps to maintain a higher average intensity.

There’s also a less significant drop in heart rate during the recovery.

For me, the uphill intensity is run between 1500m/3km intensity, whilst the downhill is run at an intensity that is slightly below marathon intensity. However, since analysing the data from these sessions it’s clear that the true intensity is actually higher than this. Making these sessions far more effective than you would expect.

How to control the intensity of tempo hills

Controlling the intensity of the tempo hill intervals, and recoveries, is key to getting the most out of these sessions.

As with any short repeated efforts this can be challenging. So what’s the best way to control the intensity?

Here, we have a number of ways to control/monitor the intensity: 

  • Pace
  • Lap Times
  • Heart Rate
  • Running Power
  • Perceived Effort

Each has their own advantages and limitations.

Running Pace

Whilst running pace can be useful during longer intervals, these hills are too short for it to be effective. Pace (whether it’s measured with GPS or a footpod) is generally a little too erratic, to be useful when intervals are this short.

Lap Times

Keeping a check on lap times for the uphill and downhills can be useful, especially if you have lap data from previous sessions. You can then try to consistently hit the target lap times for the uphill and down hill sections. This can then be adjusted as the session goes on, if these feel too easy.

Heart Rate

Heart rate gives an indication of the actual level of physiological stress during the hills. 

With heart rate the response is slightly delayed, and any rise in heart rate, occurs several seconds after the increase in work rate. Heart rate is therefore less effective for controlling intensity during individual intervals. However, it can be used to monitor the effort level across the session.

In particular, it can be a useful indicator of whether intensity is too high, or low. This is particularly useful at the start of a session – when intensity is too high at the start of the session, the intensity suffers over the second half. 

In this way, heart rate monitoring can be used to keep intensity in check.

We also need to consider cardiac drift – where heart rate continues to rise even if intensity is maintained. To take account of cardiac drift you need to ensure heart rate doesn’t rise too quickly over the first half of the session.

Running Power

If you use a running power meter you can monitor intensity in real time to control work intensity. I use this to monitor the average power of the intervals as well as the the average power for the session (combined uphills and downhills).

Although power provides useful, additional information, these hills are really a bit too short for power to be an effective way, to control the intensity during individual intervals. Having said that, it gives us additional information that can then be used along with heart rate, lap times and perceived effort.

As we’ll see in a minute, average power doesn’t represent anywhere near the true intensity of these hills.

Perceived Effort

Ultimately, if you can master perceived effort – the awareness of how hard an activity or exercise is – you will find this session a lot easier to control. In fact, it’s key skill to master as a runner!

With perceived effort we bring our awareness to our perception of how hard the interval is. Allowing us to consider the following questions: how intense is the effort? Is the effort sustainable across the whole session? Am I pushing the recoveries too much? Could I push myself a bit harder on the uphills?

This awareness allows you to control the intensity more effectively. But to master this you really have to be prepared to step away from complete reliance on technology, and risk having faith in your own ability to control intensity yourself.

Sure, you will get it wrong a few times on the way. However, mastering this key skill is vital to getting the most from these sessions, as well as for maximising your running performance and ability. It really is worth setting time aside to practice this.

How I control the intensity during tempo hills

My preference is to focus most attention on perceived effort. But I still take into account heart rate, and running power using the Stryd footpod.

I also check lap times for the uphill and downhill sections to maintain consistency.

An important note on heart rate

Whilst heart rate is less effective for controlling effort during individual intervals, it still has a purpose for controlling intensity across a session. In particular, heart rate gives you a measure of the actual physiological stress you are experiencing during the workout. It also accounts for daily variations in fitness and fatigue. And can be an early warning if something is not quite right.

As mentioned earlier, pushing the intensity too much over the first half of these sessions, can negatively impact intensity over the second half of the session. With tempo hills it can be really useful, to deliberately go a bit easier over the first few intervals. In this regard, we can use heart rate to keep intensity in check: if your heart rate rises too quickly over the first few intervals, back off slightly until this settles down.

The image below shows how starting at a lower intensity over the first few intervals can allow you to maintain a more consistent effort (see running power) over the rest of the workout.

You can also clearly see the effects of cardiac drift – where heart rate continues to rise throughout the tempo hills session – even though power remains fairly consistent.

Tempo Hills - running power and heart rate

Why are tempo hills so effective?

For me, tempo hills have always proved to be highly effective for improving running fitness and performance. But why are they so effective?

In short, this is because they combine the benefits of interval training, with an average intensity that’s very close to threshold intensity.

By exercising above and below lactate threshold intensity, we combine the benefits of aerobic and anaerobic training, lactate threshold and VO2max training, and also gain the benefits of downhill running as well as uphill running.

In fact, as it turns out the uphills can be run at an intensity that’s significantly above threshold.

Let’s breakdown why they are so effective:

#1 The average intensity is very close to lactate threshold

Once you’ve run this session a few times, you’ll find that your average intensity will increase. And with consistent training, it’s possible to maintain an average intensity (uphills + downhills) that’s very close to lactate threshold intensity. Making this a great session for lactate threshold development.

In the image below you can see power data from a tempo hill session, consisting of just over 25minutes of continuous tempo hills. I’ve highlighted threshold intensity – in terms of running power – so you can see, how running power oscillates from above threshold (uphills), to below threshold (downhills).

Tempo Hills Threshold Power

Here you can see how running power alternates between short periods above threshold (uphill efforts), with short periods below threshold (downhills).

The average power for the 25mins of tempo hills was 334w – just 4w (~1%) below threshold power. In fact, during the workout, 64% of the total training time was spent at a running power that was at or above the threshold training zone – only 36% of training time was below threshold intensity.

Because the spikes in power are quite significant (we’ll look at this shortly) you’re getting more than just the benefits of training at threshold intensity. You’re also working significantly above threshold for large parts of the workout.

#2 We also develop aerobic capacity (VO2max)

Running at threshold intensity is great on its own for developing aerobic fitness.

However, by pushing the uphills above threshold intensity we also work maximal aerobic capacity.

The data from my tempo hill sessions, shows that 41% of total training time was spent at a power equivalent to or above the VO2max training intensity zone.

The interesting thing here, is that if we were just looking at the average power for the intervals, we significantly underestimate intensity. In fact, the average power for the uphill intervals was below VO2max power.

However, there were large periods where power was significantly above VO2max intensity.

So why does average power not reflect the true intensity of the intervals? The reason here is mainly due to the lower power at the start of each interval (acceleration phase). Here the recorded power was around 40% lower over the first 5 seconds of every interval. This pulls the average intensity down significantly. But it also tell us that the average power for the remainder of the interval must be significantly higher.

Clearly it’s important to look beyond averages, when analysing data.

So as if training at an average intensity equivalent to lactate threshold wasn’t enough. We now know 64% of total training time, was at or above threshold training intensity. And ~41% of the total training time (or ~10.5minutes) was spent at an intensity equivalent to or above VO2max running power!

So as well as training the lactate threshold we’re also training aerobic capacity.

And if that wasn’t enough…

Improved anaerobic endurance and conditioning

The most surprising part – when I looked at the power data – was just how effective these hills were for hitting the anaerobic training zone.

Surprisingly, 22% (~5.5minutes) of the total training time, was spent at a power that was in the anaerobic training zone.

So not only are these hills great for lactate threshold development and maximal aerobic capacity (VO2max), they are also great for training anaerobic endurance and anaerobic conditioning.

Often there is a concern that reducing the recovery length, can negatively affect the work intervals. Clearly, recovery is important, but in this case a high work rate can still be maintained with a relatively short recovery.

Whilst the shorter recoveries mean you won’t hit quite the same intensity on the uphills. They do give us the combined benefits of training the lactate threshold, aerobic capacity and anaerobic endurance and conditioning. It’s also beneficial for both cadence and stride length.

Develops running cadence and stride length

Tempo hills are also great for working both running cadence and stride length. Both cadence and force per foot strike are slightly lower than when using longer recoveries. However, as this is combined with a strong endurance component – repeated efforts with short recoveries – we are improving our ability to maintain both a fast cadence and good force per foot strike.

Here, we’re not developing cadence and stride length in the same way that we do during hill sprint workouts and anaerobic capacity hills. We’re not pushing the upper limits of cadence and stride length. Instead, we’re developing our ability to sustain a good cadence and stride length, over prolonged periods and when our legs are fatigued.

Tempo Hill Workouts

Hopefully by this point you’re looking to give these sessions a try.

A word of caution first, these hills can be very intense and fatiguing. It’s important that you are well conditioned, and have completed a significant amount of base training. Ideally, complete  preparatory hill training, such as longer hills, before attempting tempo hills.

When you first introduce these, start at a lower intensity and don’t push the uphills too intensely. After a couple of sessions you’ll start to find these easier, and be able to increase the intensity of both the uphills and downhills.

Initially, split the intervals into smaller intervals, and overtime progress these towards running these as one continuous tempo hill session.

Basic tempo hills Progression:

The following examples show how to progress tempo hills (TH) – from easier to harder sessions.

  • 4 x 5 mins TH, 2-3mins recovery between sets
  • 4 x 6 mins TH, 2-3mins recovery between sets
  • 3 x 8mins TH, 3-4 mins recovery between sets
  • 2 x 12mins TH, 3-5 mins recovery between sets
  • 3 x 10mins TH, 3-5mins recovery between sets
  • 1 x 25-30mins TH

Advanced tempo hill variations:

Below are some more advance tempo hill variations.

Advanced Tempo Hill Session #1:
10min Tempo Run + 3-5mins easy + 10mins TH + 3-5mins easy + 10min Tempo Run

Advanced Tempo Hill Session #2:
10mins TH + 3-5mins easy + 10min Threshold/Tempo + 3-5mins easy + 10min TH

Advanced Tempo Hill Session #3:
10mins TH + 3-5mins easy + 10min Threshold/Tempo + 3-5mins easy + 10min TH + 3-5mins easy + 10min Threshold/Tempo

Advanced Tempo Hill Session #4:
20mins TH + 20min Tempo

Advanced Tempo Hill Session #5:
10min TH + 4-5mins easy + 6 x (30 sec Hills – hard efforts, 2-3min recoveries) + 4-5mins easy + 10min TH

How To Incorporate Tempo Hills Into Your Training

Tempo hills have that unique combination of a high average intensity combined with a strong aerobic and anaerobic component. On top of this there is increased muscle fibre recruitment which places greater stress on the nervous system.

Taken together this makes these intervals very effective for training, but also very fatiguing.

Because of this we need to be cautious with when and how often we use these sessions. Especially if we really push the intensity.

From my own experience, 2-3 of these sessions during a 8-12 week training block can be very effective.

When to incorporate these?

I find the training adaptation from these hills is fairly quick. And often, just 2-3 weeks (sometimes quicker) is enough to see a progression. However, due to the intensity of these sessions, we don’t want to use these too close to key races.

A good approach is to Include 2-3 of these sessions, 3-6weeks before a key race. As always this is not the same for everyone.

You can see examples of how to incorporate these in the following 10k training plans, that I’ve put together:

Elite 10k Running Training Plan
Advance 10k Running Training Plan

How hard to push these?

It really depends on your current run fitness, ability to recover between intervals, and ability to push through the fatigue, when that inevitably sets in. 

For me, I push the uphills at between 1500m and 3k intensity. However, when I first reintroduce these into a training block, the intensity will be lower (~3k/5k intensity).

If you haven’t done these before start at a lower intensity and see how that goes. Then look to increase the intensity over subsequent sessions.

When it comes to getting the most out of the session. Always run the first few at a slightly easier intensity. And gradually increase each one until you feel like you’ve reached an intensity that you can sustain across all of the remaining intervals. You can see an example of this in the earlier image showing “running power and heart rate during tempo hills”.

What about the intensity of the recoveries?

I like to think of the recoveries as a steady intensity, that’s just below marathon intensity. It should feel like you’ve eased off the gas slightly, but are still running at a decent “steady” down hill pace with the assistance of gravity.

If you want to read more about different types of hill training, you can view the related articles below.

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