I came across intervals.icu a couple of years ago, via an article written about 2021 Olympic road race winner Anna Keisenhofer. In the article she noted the complex and adaptable graphics that intervals.icu delivers, based on data drawn in from a number of sources.
I found a brief video on YouTube that shows the capability of intervals.icu in planning, reviewing and analysing training session data. I'll summarise my data flow below that.
https://www.youtube.com/watch?v=VOBnGTnMavA&t=12s
Intervals.icu is a web app which is free to use, though a subscription (currently £9 quarterly, I'm not sure what this corresponds to in other currencies) obviously helps to support the site.
At first glance, intervals.icu looks like most other training app. It has the usual calendar view, and an excellent page of graphs. What's particularly exciting to me is the extent to which you can fine-tune the data presentation to suit your needs. This is likely limited only by ones scripting ability. I suppose that Golden Cheetah's use of R also resembles this.
In my use case, I have data flowing in automatically from TrainerRoad (which I use to set up training programmes), Garmin Connect and Polar Flow. I also automatically bring in HRV data from the HRV4Training Android app. You can also sync from Strava (I think that was the starting point for the app), though as I'm not a serious user of Strava, I don't do this.
The fitness view is where you can track a variety of parameters - it's all very configurable, so you can see what you want to see. An example is that it lets you see in advance the likely impact of upcoming training plans on fitness, you can see correlations between breaks from training for example due to illness or travel away from your usual training mileu.
An attractive feature is in the Power screen, where you can indulge yourself in a seemingly infinite range of analyses. One example is a comparison of Power over several durations in the context of your peers. For example, the following shows how I compare to others in the 60+ year age group:
You can see that I'm basically a time triallist rather than a sprinter!
Comparison of parameters by season is interesting. Here's a comparison of power vs HR for the last three years:
Other features:
- You can design workouts - again, I use TrainerRoad for this, so it's not something I've used other than an initial play.
- You can contact a coach
- Set up groups
- intervals.icu covers a very wide range of sports though it's at its most powerful with those sports for which reliable power measurement is possible.
- The range of features is continually being updated, with very good communication from the developer via the forum.
It's quite hard to do a truly detailed review of the app (though some of the YouTube videos help) - you should really join up and start playing with the extraordinary range of options.