Question about sprints for "cardio"

[Smokes]

I've done these multiple ways--airbike, hill sprints, 1 straight away on a 1/4 mile track (jog the rest), etc. Personal experience:

1) They're all exhausting during the exercise. If you truly go all out balls-to-the-walls for those 20 seconds.

2) Each successive interval is slower than the prior (lower watt output on machines, slower straight away times, lesser hills that can be tolerated, etc).

3) The sprinting (either sprints or hill sprints) does tend to take me a little longer to feel recovered from

[Lucasl7d]

Yes, pounding aside, sprinting's more demanding overall.
Interesting study, but the subjects were sedentary: maybe the intensities they were able to generate, on bikes, is considerably lower than they could have if they had had prior training. More so if they'd done the sprints on a track, those would look very different than compared to a trained individual I think.

[Naturegirl]

I believe that the recommendation is based on this study: https://journals.plos.org/plosone/ar...l.pone.0154075
And you're right, it's easier to do on a cycle. Your body isn't taking the same pounding as sprinting.

[Lucasl7d]

Hello everybody, I'm new, this is my first post!
Related to the post by Hans and Franz (sickening screen name), I wonder in The Bridge and in general, what do people mean by 20" sprints followed by x amout of time at low intensity.
Specifically the meaning of sprint. In my case, what I can do for cardio is to run, but a 20" sprint as I understand it is a pretty high effort, 90% or more. After which I have to rest for a couple of minutes to be able to do it again at about the same intensity.
The way I could do it repeatedly for 20-30 minutes is to do it a a lower intensity similar to a warm up for sprints where you do a controlled run at an intensity as easy as possible that allows you to keep a good running/sprinting technique but it should be easy. Like you could keep for 400 m or so, but for the 20". And even then I suspect I will collapse after 4-5 "sprints"+ jogs.
I understand that kind of 20" sprints on a bike or rower can be easier but running's very taxing.
Anyway, thanks in advance for the comments!
Lucas