Intervals.icu analyses your rides, runs, swims and other activities (with and without power).
It provides basic and advanced analytics and planning in an easy to use web interface with support for desktops, phones and tablets.
Intervals.icu is free to use, with additional features should you choose to subscribe.
Connecting Intervals.icu
Signup to create your Intervals.icuaccount.
To execute workouts, you’ll need to connect Intervals.icu to your watch, using one or more of the connections listed on the Settings page.
Building a structured workout
You can build your own workouts from the Activities page by clicking on the date where you want to create the workout, choosing your workout type (e.g. Run), then typing or copy/pasting your structured workout into the Description of the workout.
There’s a Workout builder help page explaining how to create or edit workout details.
Downloading planned workouts
Planned workouts can be downloaded to Garmin, COROS, Wahoo and Suunto watches.
Intervals.icu will automatically sync the next week of workouts, so that your workouts will be available when you start your run.
Due to restrictions on the destination platforms, Intervals.icu cannot download planned workouts to Polar and Apple watches.
Uploading completed workouts
Once you’ve connected Intervals.icu, completed workouts will be uploaded from your watch.
If you have an Apple Watch, you’ll need to use a 3rd-party app like HealthFit or Health Sync to upload completed workouts to Intervals.icu.
Reviewing second-by-second workout data
You can review second-by-second workout data using the Activities page.
Select your workout to view your metrics. You can choose which metrics you want to see, as well as summary and ‘per lap’ metrics.
Manual and automatic laps
Intervals.icu defaults to using the lap data from your workout file. If you want to view metrics per km or per mile it’s possible to do this using custom charts, or by using the interval editing commands (merge, split etc.)
Reviewing a workout range
You can also use the interval editing commands (merge, split etc.) to isolate specific workout ranges, and to restore the original laps (using Actions > Use Laps) when done.
Reviewing/Updating Threshold Power
When using Intervals.icu, Threshold Power is referred to as Functional Threshold Power (FTP) or Critical Power (CP), depending on the model you choose.
Auto-Calculated Functional Threshold Power
Intervals.icu can estimate your FTP/CP using data from the last 90 days of training, using your choice from four different calculations. You can choose which calculation to use in the Options setting on the Power page.
I found that, for me, ‘2 parameter CP’ aligned with calculations from other platforms, but any of the choices would be suitable as long as once you choose you continue to use that choice – don’t change your choice.
To ensure your FTP/CP is accurate, you should ensure you regularly run maximum efforts at a selection of durations. The calculation requires “2 maximal efforts, one of 3-5 minutes and another of between 10 and 30 minutes”, as described on the Model Power Curve page.
To ensure that no maximum efforts drop out of the 90-day window, you should run maximum efforts every 4-6 weeks (alternating across the durations).
Manual FTP
Intervals.icu offers the ability to manually set your FTP/CP to plan targets for structured workouts.
To manually set your FTP/CP:
- open the Settings page
- select RUN in the activity section
- enter your FTP in the Power Settings
Your PDC (and workout maximums)
By using the Power page (and selecting ‘RUN’), then selecting ‘OPTIONS’ > ‘Show model power curve’, you can review your Mean-Max Power (MMP) curve. Intervals.icu uses your maximum efforts and best efforts to show your MMP.
You can hover over different parts of your MMP to see which completed workouts contributed to the curve (the data as the top of the vertical line shows the workout date). You can use the ‘POWER CURVES’ and ‘OPTIONS’ selections show different views of the underlying data.
Intervals.icu also shows a modelled curve based on the calculation you’ve chosen for estimated FTP – for example, choosing the ‘2 parameter CP’ plots the CP curve in the chart.
Stress Scores
When using Intervals.icu, Stress Scores are referred to as Training Load (or Load for short).
Load is calculated for each planned and completed workout, and can be added as an additional metric in the second-by-second activity view.
Training Load
Intervals.icu offers Fatigue, Fitness and Form scores:
- Fatigue measures the shorter-term impacts of your training.
- Fitness measures the longer-term impacts of your training (your cumulative training load).
- Form is the difference between the 7d and 42d averages.
These metrics are shown on the Fitness page.
Note that the names of these metrics may be a little misleading, as the metrics are relative, sport-specific indicators based on completed workouts – they are not your actual fatigue or fitness.
Stress Balance
When using Intervals.icu, Stress balance is referred to as Form, and is shown on the Fitness page.
Intervals.icu offers an interpretation of your Form (e.g. High Risk, Optimal, Grey Zone) and while this may be accurate for a majority of runners (based on runner averages), it may not be accurate for you. Instead, complete Activity #10 (in the Training Stress book chapter) to monitor Form over a number of days (or weeks). This will build your experience for how well the Form scores match your perception of your training load.
Ramp Rate
Intervals.icu offers a Ramp Rate using the Fitness view.
To add Ramp Rate to the fitness chart, select OPTIONS > Ramp Rate.
Running Effectiveness
Intervals.icu does not offer Running Effectiveness (RE).
You can either add RE as a custom field (if you are familiar with javascript), or you can calculate your own RE by reviewing a workout range on the second-by-second workout view.
Running Effectiveness = (Distance / Moving Time) / (Power / Weight), where:
- Distance is in metres
- Moving time is in seconds, and is only valid if you did not pause (or auto-pause) your watch during the section
- Power is in Watts
- Weight is the weight configured in your Stryd footpod (converted to kilograms)
Alternatively, the SuperPower Calculator page describes how to calculate RE using that tool.
I'd like to give feedback ...
If you have feedback – perhaps something that’s missing/incorrect, or something that would improve the content of Part 3, please let me know in the from1runner2another Facebook group.
Updated: