This is a classic session used by many coaches for riders competing in events such as criteriums, track races or road races where the level of effort required changes frequently due to changes in peloton pace, attacks and sprints out of corners.

It consists of 10 x 20 seconds of intense effort, followed by 40 seconds of easy recovery. Then rest for 10 minutes before repeating the first block again.

These intervals can be incorporated into an indoor cycling session of less than an hour and are therefore quite manageable to fit even a busy schedule with limited training time.

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If you are looking for an outside alternative, click here to jump to that section of the page.

Due to the very intense nature of the very hard 20 seconds, your heart rate response to these efforts for the 10 minute block will be more like a sweet spot or sub-threshold effort – even with those 40 seconds of rest. For some, that’s easier than making a solid 10-minute threshold.

Golden Rule

20-second efforts should not be performed at the maximum from the start. If you do that, then halfway through the 10 minute block, you’ll start to really feel it and regret it. Your potency will also start to decrease and you will not get the full benefits of the session.

Consistency is the key. So stick to the prescribed effort level of 140-150% of critical power and the intervals will get harder and harder as the session progresses.

Another thing will be to get into the right gear for the efforts. In ERG mode this is easily done, but if you are doing the session in Level mode or outdoors, gear selection is key. Choose one that you can start pedaling from, perhaps a cadence of around 80 rpm, then increase as the effort continues.

Simply explained

The main benefits of this session are that it will help you increase the amount of power you can deploy above your threshold, helping you improve your climbing on hard-hitting climbs and tracking attacks on the run. It will also increase the repeatability of those efforts, helping you stay up hill after hill and turn after turn.

Let’s go geeky…

Another way to explain why these intervals are so good for events like crits is that they help improve your ‘Watts Prime (W’)’. It is the amount of energy above the critical power (CP) that we can use and recharge. Basically, if ‘W’ is a battery, these efforts can help increase the size of that battery. Critical Power is an alternative to FTP for evaluating progress, find out how to get your numbers and use them in our Critical Power explainer here.

They also help to strengthen the resistance to fatigue generated by the production of inorganic phosphate (Pi). This happens with changes in pace from easy intensity to more difficult intensity. As the initial power boost uses the phosphocreatine (PCr) pathway to produce energy quickly, your aerobic and anaerobic pathways will then provide the rest of the energy.

The problem is that using the PCr pathway leaves behind metabolites – in this case Pi – that can affect the contractile function of muscles, and therefore our ability to contract muscles and produce energy. But by training like this, we can increase our ability to eliminate Pi and thus experience less fatigue.

Additionally, active recovery (easy rotation) was found to be more effective at removing Pi from muscles and resynthesizing it into phosphocreatine than no pedaling. So one way to make this session harder would be to not pedal during the 40 second rest.

Sunny ? What would you say…

The image shows a cyclist exercising outdoors.

(Image credit: future)

As the boulders only last 10 minutes, they can be done fairly easily outdoors in most locations. Ideally, you want a flat or undulating stretch of road with minimal sharp turns and no junctions.

These can be done uphill, but keep in mind that the recovery will likely be at a higher power output due to the uphill, making the session more difficult and possibly limiting power output during efforts of 20 seconds.

As with any outdoor endeavor, it is good to know the stretch of road well so that you are aware of hazards such as potholes or gravel corners. For riding outdoors, you can also increase the warm-up and cool-down time around exertions, as well as the 10 minutes of easy riding between blocks. The main thing is to get the 10 minute blocks of 20/40 on the spot.

Stay tuned for next week’s session, we’ll be bringing you a new workout every Monday.

In the meantime, you can find others indoor cycling workouts for turbo training here, sessions specifically if you don’t have 30 minutes free to train here and training plans for beginners, intermediates and runners here.