I use a free iPhone app called IntervalTimer, with a cheap indoor exercise bike. I spin in least resistance for warmup/interval “low” rest phase, and whack the setting to full when doing the “high”
However, i’m of the opinion that I’d rather be out on the real bike that I want the benefits for at the weekends.
You can customise the interval set sizes and timings fully.
I’ve got an hour routine set up, so I can watch a downloaded documentary (e.g. its how i wanted Planet Earth II)
I record using a HRM and it produces a nice spikey graph.
Currently the app is set to.
– 10 min warmup
5 sets of 30 seconds full on, with 2 min break
6 sets of 1 min full on, with 2:30 min break
5 sets of 30 seconds full on, with 2 min break
– 15 mins cool down
By watching HRM data I can see when i’m warmed up etc.. its around the 7/8 min mark. so 10 isn’t too bad. I could probably should add make it 4 or 5 smaller sets and lose some of the cool down. its been evolving almost every time I do it.