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Drew's Power Intervals


Phased constrained interval training based on power. The field is configured using a programming language I have created to describe the interval training. There is a cross hair which shows how far through the phase and where in the zone you are. It is fairly ambitious in view of the size constraints of a field and I feel like I have squeezed a quart into a pint pot. The language is simple and accessed through configuration of the field in the app or online. If we have selected duration (I can also select distance) in minutes then a phase is described by say [5,1] which is five minutes in zone one. Intervals are linked together with a plus sign so [5,1]+[5,2] is a warm up starting in zone 1 for five minutes then zone 2 for five minutes. I can use parentheses and a multiple such as 4*( [5,5]+[2,2]) which is four lots of the linked phases. It is possible to nest these and produce highly complex workouts such as [5,1]+[5,2]+2*(3*([5,4]+[2,2])+[5,1])+[10,1]. You may run into memory issues on devices with smaller memories (such as the F3) with complex workouts. I would have liked to have done more but am really hitting the memory ceiling hard. The next step would be to create an application. It is on my todo list!

What’s New

Displays minutes and seconds rather than decimal minutes.</p><p>Displays repetition numbers.</p><p>Improved stability of the power reading.</p><p>Writes power data to Connect IQ.</p><p>

Additional Information


This app requires access to:

  • Record additional information into activity files
  • Edge® 1000 Edge® 1000
  • Edge® 1030 Edge® 1030
  • Edge® 1030 Plus Edge® 1030 Plus
  • Edge® 1030, Bontrager Edge® 1030, Bontrager
  • Edge® 130 Edge® 130
  • Edge® 130 Plus Edge® 130 Plus
  • Edge® 520 Edge® 520
  • Edge® 520 Plus Edge® 520 Plus
  • Edge® 820 Edge® 820
  • Edge® Explore Edge® Explore
  • Edge® Explore 1000 Edge® Explore 1000
  • Edge® Explore 820 Edge® Explore 820
  • epix™ epix™
  • ForeAthlete® 230J ForeAthlete® 230J
  • ForeAthlete® 235J ForeAthlete® 235J
  • ForeAthlete® 630J ForeAthlete® 630J
  • ForeAthlete® 735XTJ ForeAthlete® 735XTJ
  • ForeAthlete® 920XTJ ForeAthlete® 920XTJ
  • Forerunner® 230 Forerunner® 230
  • Forerunner® 235 Forerunner® 235
  • Forerunner® 630 Forerunner® 630
  • Forerunner® 645 Forerunner® 645
  • Forerunner® 645 Music Forerunner® 645 Music
  • Forerunner® 735XT Forerunner® 735XT
  • Forerunner® 920XT Forerunner® 920XT
  • Forerunner® 935 Forerunner® 935
  • fēnix® 3 fēnix® 3, quatix® 3, tactix® Bravo
  • fēnix® 3 HR fēnix® 3 HR
  • fēnix® 5 fēnix® 5, quatix® 5
  • fēnix® 5 Plus fēnix® 5 Plus
  • fēnix® 5S fēnix® 5S
  • fēnix® 5S Plus fēnix® 5S Plus
  • fēnix® 5X fēnix® 5X, tactix® Charlie
  • fēnix® 5X Plus fēnix® 5X Plus
  • fēnix® Chronos fēnix® Chronos
  • vívoactive® vívoactive®
  • vívoactive® 3 vívoactive® 3
  • vívoactive® 3 Mercedes-Benz® Collection vívoactive® 3 Mercedes-Benz® Collection
  • vívoactive® 3 Music vívoactive® 3 Music
  • vívoactive® HR vívoactive® HR
Average Rating: (11 Ratings)

Davide Sereno
June 9, 2020 | Version 1.5

Does it work with the Garmin Dynamics sensor? Or need a sensor like Stryd?

February 7, 2020 | Version 1.5

Hi Andrew, Sorry to only give 3 stars when I think it deserves more but unfortunately I can't get it to work. My problem is that the horizontal bar of the power stays at the bottom, it does not move at all. Is it compatible with the Stryd sensor? In the parameters of the zones is there a tip on the value to write (Example: if I have 200 must write the value 100 or 50 or 0.5 for 50% for example but I have already tried them First 2). Other tips to know ? Thank you. Regards

Developer Reply
February 8, 2020, DrewShardlow

Connect your Stryd to the watch as a power pod. With this field you also need the Stryd power field to record your power metrics to PowerCenter. The settings clearly indicate percent values are required. I have not developed this field further as it is not possible to do this within the memory constraints of a field (c.f. an app) and have put my development effort into Drew's Intervals. I suggest you take a look at that. It links directly to Stryd and PowerCentre and works with third parties such as TrainingPeaks and Today's Plan.

George Kalogeris
November 20, 2019 | Version 1.5

Great data field! Really helpful for structured workouts.Congratulations. The idea of % of FTP in zones is really AWESOME. What I'd like is many zones so I don't mess them for staying e.g at 94-96% and then 75-80%. What I'd also like is a Lap match e.g. [L1,1]+[L2,3]+[L3,1] where the first parameter is not time but Lap number triggered either manually or by Garmin's Workouts

Richard Tong
July 10, 2019 | Version 1.5

No detailed instruction on how to change the interval. I hope you can provide a way to change the interval.

Developer Reply
July 11, 2019, DrewShardlow

I suggest reading the description which includes an overview of the interval syntax then configuring via Garmin Connect. You write a simple expression describing the session. You can create pretty much any phased training with power that you can think of. If you need a GUI to do this then this field is not for you. A rather tetchy two star review without properly exploring the fields capability makes it highly likely it is not.

Volker Schuboth
May 21, 2019 | Version 1.5

I've been looking for an app for a long time, which are looking for my workouts that are based on watts. Finally I found one with this app. great app

April 24, 2019 | Version 1.5


December 6, 2018 | Version 1.5

Haven't tested it yet, but looks great. Question: if I choose distance, what is the unit used, the one in the watch settings? And can I use decimals?

October 27, 2018 | Version 1.1

Задумка хорошая, алгоритм очень простой, разраб продолжай реализацию

Developer Reply
October 27, 2018, DrewShardlow

Спасибо за обзор. К сожалению, в памяти еще нет места для дальнейшего развития идеи в качестве поля данных. Следующим шагом было бы изменить его на приложение, так как это даст мне больше памяти и еще множество опций, включая возможность сестра сайта (возможно, Stryde или Trainingpeaks было бы интересно).

Emma Clare
October 26, 2018 | Version 1.1

It is the only multiphase power based training around at this time. Took me a while to understand the syntax of the interval training language but now I have got the hang of it it seems really simple yet very powerful. Nice to be able to build an interval on my phone just before doing the session.