Introductory intervals - how to get started on boosting your endurance with indoor training

Coach Deena Blacking talks through a key session in getting you started with indoor training

This article is produced in association with Zwift

The days are short and – let’s face it - the weather is dismal. ‘Tis the season to ride indoors. Luckily Zwift can promise an endless supply of indoor workouts; the tricky part is knowing which one. Zwift offers more than 1000 structured sessions, and it can be overwhelming to know how to pick the one that’s best for you. Luckily Coach Deena Blacking of is here to help you answer the question, how do I choose a session that’s right for me?

For this series of articles we asked Benjamin Bathurst, Rouleur’s digital marketing manager, to be our guinea pig. Ben’s only time to ride is often after work. Rather than ride in the dark (and cold and rain), Ben chooses to ride indoors on a stationary trainer with Zwift: “Zwift provides me a way to switch off after work with the side benefit of having a great work out. You just log on and your training plan is there waiting for you all loaded up”.

To pick a workout that fits your needs, be clear about what you need before you start the searching. Here are four key questions to ask yourself:

(1) What do you want to achieve? i.e. Are you training for an event or fitness goal? (2) How much time do you have? (Per week and per session?)
(3) How much variety do you need in a workout to stay motivated? i.e. Are you happy with long static efforts, or will you be more engaged by workouts which change it up frequently?
(4) And finally, the most important question of all… how difficult do you want it to be?

This week we are looking at sessions for a rider who is new to structured training, wants to train for a long sportive, doesn’t have a lot of time, and wants to work hard but not kill themselves. The four-week Fondo plan, which is rated ‘beginner’ is a great place to start.

Ben and I selected ‘Introductory Intervals’ from week two of the plan. It’s a 55-minute workout that does exactly as the title describes - the session comprises intervals between two and four minutes in length, each duration at a different level of difficulty. It’s a fantastic workout because it gives you several benefits at once:

1. Develops your endurance fitness at a moderate level of effort
2. Keeps your engaged by providing structure and variety
3. Trains your ability to deliver consistent power output

Develop your endurance fitness at a moderate effort

There’s a reason the pros clock up 20+ hours a week - miles mean smiles! Unless you’re a track sprinter, your cycling fitness is founded in endurance. However, if time is limited, you need to be clever about how to develop your endurance. Indoor structured workouts on Zwift are a very smart solution.

Read more: How should I fuel for indoor training? Advice from a nutrition specialist

In this 55-minute session, you will clock up 31 minutes of moderate to reasonably difficult interval work, as well as the recovery pedalling in between. It won’t leave you for dead, but it will build your endurance base. The workout is also progressive in effort level, which is perfect for the relative newcomer to structured training.

“The workout had two pyramids of intervals, which gave a clear build up and down. My body felt ready for the harder pushes,” said Ben.

The moderate demand of this workout is also ideal for times when you can’t simply pass out on the sofa afterwards e.g. you need to be able to use your brain at work or do chores at home etc. Zwift rates it as ‘easy’ or two out of five. However, if it’s your first foray into structured training, you’re entitled to feel that it’s closer to a three!

Stay engaged with workouts that offer structure and variety

The best athletes are the ones who turn up every day. Consistently. Sadly, consistency can also be boring, especially in endurance training. A Zwift workout helps you to achieve consistency (and fight the boredom) by engaging you with structure and variety. In ‘Introductory Intervals’, the pace changes every few minutes throughout the entire workout. You are never doing the same thing for more than four minutes at a time. “The hour went really fast when compared to just wandering around Zwift,” explained Ben. “Since the session was broken into bitesize chunks, I could count down every time.”

Train your ability to deliver consistent power output

Imagine that you had 100 matches for 100 kilometres. The most efficient way to use those matches is to burn one every kilometre. But most amateurs don’t ride like that; instead, we burn through the box in a random fashion, running out of spark somewhere in the second half of the ride. By contrast, the most skilled riders, especially time triallists, will have honed this to a t, knowing how to deliver consistent power output so they can go as fast as physically possible for a given amount of energy. Whether you’re training for your first 100-kilometre event or aiming for the pro ranks, holding consistent power – knowing how to manage your energy - is a vital skill for cyclists. In Introductory Intervals, Zwift asks you to hold steady power at three different intensity levels (percentages of your functional threshold power or FTP). You do this two or three times for each level of effort. By the end of the workout, you will have a good idea of what they feel like and how they differ.

A final pro tip

If you want to level up your workout gains, turn the controllable function off and learn how to regulate your power output based on your own sensations. Ben admitted after this session: “I noticed that I was awful I was at trying to keep to zone one or two on the undulating terrain compared with the pre-controlled zones by trainer.” 

As a coach, I always recommend that an athlete tries to do most of their workouts without the controllable trainer function. Give it a go and let us know on social how you get on and share your experience. It might be tougher to begin with but if you continue to follow this process, over time you might become as steady as Ellen van Dijk or Filippo Ganna.

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