If you’ve spent any time doing formal cycling workouts, then you’re no doubt familiar with zone 4, or “threshold” type workouts. The term “threshold” is generally synonymous with other common exercise physiology terms like lactate threshold (LT), anaerobic threshold (AT), and Maximal Lactate Steady State (MLSS) [1].

In general, these laboratory-based concepts make an attempt to pinpoint the deflection point where your body is no longer able to balance production and clearance of lactate in the blood, leading to an exponential rise in blood lactate [2].

Short on time? Check out our quick tips on Threshold workouts.

This image shows a typical blood lactate test in a laboratory setting. Our Y axis (vertical) shows blood lactate concentration while our X axis (horizontal) shows intensity in watts.

In this example a sample of blood is collected every minute at the completion of each stage (on each stage the intensity is bumped up by 5w).

On average, riders see an exponential increase in blood lactate in a wide ballpark of 4 mmol/L. In this example the riders power at lactate threshold would be 285w.


In an effort to more conveniently utilize laboratory-based measures of cycling physiology in training and racing, Dr. Andrew Coggan and others came up with the concept of Functional Threshold Power (FTP) [3].

FTP translates to the average power a cyclist can produce over a roughly sixty minute all-out effort. This functional application of the lactate threshold concept makes “FTP” a convenient and practical method for describing and prescribing cycling training [4]. FTP’s convenience, and reasonable accuracy at quantifying cycling fitness is the reason it is chosen as the anchor for most power based training systems.

In simple terms, when done accurately, and tracked consistently, the FTP concept does a great job of helping us describe larger changes in our fitness, while serving as a convenient method to prescribe various training intensities.

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Context

In a training context, threshold rides are designed to accomplish two things.

1. Progressively increase the amount of total time you can spend riding near your threshold.

2. Progressively increase the power you can produce while riding at your threshold. 

The threshold range of cycling intensity receives extra attention because sustained, high intensity riding often defines the most crucial aspects of competitive cycling events (like long climbs and time trials). Generally speaking, the more power you can produce while riding near your lactate threshold, the more competitive you’ll be across the spectrum of cycling performance [2].

Energy System Target

Threshold rides target the oxidative energy system drawing power mostly from carbohydrate. Threshold rides also aim to improve our ability to clear lactate from the blood while more efficiently using it as an energy source. 

Nutritional Considerations

Threshold workouts are where you’ll really begin to notice your body’s higher usage of carbohydrate to power your ride. Put simply, if you’re aiming to execute a high quality threshold ride in the afternoon, it will be helpful to begin thinking about fueling adequately with carbohydrate as early as your breakfast [5].


Pay close attention to fueling before any threshold workouts. For any longer threshold sessions adequate carbohydrate intake will be crucial for nailing a good workout.

You don’t need to overdo your carb fueling, but skipping meals, or avoiding carbs throughout the day will almost certainly crater any chance you have of executing a high quality threshold ride in the afternoon or evening. 

So what do you do if you’re trying to restrict carbohydrate or find yourself near the end of the day having not eaten very much? In this case you have two options. 

1. Forget about your power targets and switch your mind to RPE exclusively, give the ride your best effort, and call it a day.

2. Adust your power targets and shift the intensity down to the tempo range, in essence, an intensity that should require less carbohydrate to fuel your effort.

The takeaway of course is that the higher the intensity of your workout, the more strategic it pays to be with your carbohydrate fueling.

Pacing

With training zones one through three we don’t pay much attention to warming up before our workouts. In general I recommend athletes getting in whatever type of warmup (long, short, easy, or hard) that feels right. Once we cross over into threshold territory the specificity of our warmup becomes more important.

In short, for higher intensity (≥zone 4) workouts, research suggests that utilizing a short, higher intensity effort before your primary efforts can help to “prime the aerobic pump” of exercise, resulting in improved performance for subsequent hard riding. To read more about the science and theory behind a great warmup, check out this post over at our blog.


Warmup Template

If you prefer to jump straight to the goods, here’s a template for a science-backed warmup to execute before all (training or racing) your high-intensity efforts.

This template is for a 20m warmup. Fine-tune your intensity and rest duration before the start of the main set to see what works best for you.


Now that we’ve covered a good warmup to use before your threshold rides, lets take a look at the two primary methods we use to target your threshold range of training. The first and most popular is a continuous threshold ride.


Threshold (continuous)

A typical continuous threshold intervals workout would be a set of 2 X 20m efforts at 98% of your threshold)


The second type of workout designed to target your threshold uses intermittent intervals. These are usually a series of shorter intervals broken up with short periods of rest.


Threshold (intermittent)

An example of an intermittent threshold workout would be 2 X 30m of (30s on/30s off) efforts. 


Which method is better? I think the best threshold workout is the one that produces the greatest improvement in performance alongside the lowest increase in RPE.

Do continuous threshold intervals make you want to quit riding the bike? Then an intermittent approach might make more sense, even if it results in a slower rate of improvement. 


Screen for Threshold rides

Threshold rides are where it can help to bring more immediate feedback to your computer screen. You can see in our example, our focus is narrowed to the duration of our interval, the average power of the interval, and a current reading of the power fueling our overall lap effort. In this instance, you have everything you need to focus on the effort at hand.


One final thought. Threshold workouts often fall victim to over-precision. While power meters have introduced an incredible ability to be hyper specific with our interval targets, they’ve also introduced an unhelpful emphasis on precision. Does it matter if you execute a threshold workout at 300w as opposed to 295w? 

Probably not. Give yourself the flexibility to utilize a range in your threshold intervals. On days where you feel great, commit to maximizing your threshold rides and pushing the upper end of your range. On more challenging days, allow yourself to do less, shifting your pacing strategy to prioritize RPE over the razor sharpness of a power target. 

Threshold workouts are a great training grounds for developing the mental flexibility to take advantage of the days when you feel great, while staying in the game and be consistent on days you’re not at your best. If you’re constantly expecting a best effort every time you saddle up for a threshold workout, you’re committing to a path of self destruction on the bike. 

Reducing RPE

Threshold workouts are hard, and the subsequent cost in RPE can be significant. For this reason it makes sense to develop your own strategy to actively reduce your RPE as much as possible for your threshold workouts. 

Here are four ways I’ve found to help lower RPE on threshold workouts.

1. Listen to music. Safely of course. Research has confirmed what anyone who has ridden hard on the bike already knows. Listening to music can take a significant sting out of riding hard [6]. I’ve found for any intervals above a Tempo intensity, queuing up some hard driving music is an absolute necessity. Some may argue that since you can’t listen to music during an event, you should practice riding hard without music but I think this advice is misguided. If you can turn down RPE even a small amount, for the same power output when training, music is a worthy investment if it works for you.

2. Lean on carbs. We already discussed some nutritional considerations but they’re worth mentioning again in relation to RPE. Trying to nail a threshold workout without being properly fueled with adequate carbohydrate is a loosing proposition. Not only will the quality of your workout suffer, you’ll needlessly make your workout feel harder. Restricting carbs blows up your RPE, don’t do it.

3. Utilize caffeine. This can get tricky if you’re primarily riding in the afternoon where caffeine might crater your sleep, but if you’re lucky enough to ride in the morning, caffeine can provide a significant reduction to your ride RPE.

4. Be mindful of heat. If you’re trying to nail high quality threshold intervals in the blazing heat, you’re going to be frustrated. If possible, opt instead for riding during the cooler temperatures of the morning. If you can’t ride when it’s cooler, commit to a systematic cooling strategy during your ride and adjust your expectations while shifting to RPE as your training target. 

References

  1. Klitzke Borszcz, F., A. Ferreira Tramontin, and V. Pereira Costa, Is the Functional Threshold Power Interchangeable With the Maximal Lactate Steady State in Trained Cyclists? Int J Sports Physiol Perform, 2019. 14(8): p. 1029-1035.
  2. Kenney, W.L., J.H. Wilmore, and D.L. Costill, Physiology of sport and exercise. 2020, Champaign, IL: Human Kinetics.
  3. Allen, H.C.A.R.M.S., TRAINING AND RACING WITH A POWER METER. 2019, [Place of publication not identified]: VELOPRESS.
  4. McGrath, E., et al., Is the FTP Test a Reliable, Reproducible and Functional Assessment Tool in Highly-Trained Athletes? International journal of exercise science, 2019. 12(4): p. 1334-1345.
  5. Cornford, E. and R. Metcalfe, Omission of carbohydrate-rich breakfast impairs evening 2000-m rowing time trial performance. European Journal of Sport Science, 2018: p. 1-8.
  6. Stork, M.J., et al., Music enhances performance and perceived enjoyment of sprint interval exercise. Med Sci Sports Exerc, 2015. 47(5): p. 1052-60.