LT on static bike?

Hey everyone, this is something that's happened to me recently so I was wondering if someone could clear it up.

Basically, I suck at cycling, however this week I've been forced to use the static bikes in the gym due to a minor strain on my left Achilles tendon. While cycling, I'm able to keep my heart rate at around 73% consistently for about 45 minutes (until I get totally bored)- so I'm maintaining up my aerobic fitness, at least.

However, while cycling at these speeds, my legs are feeling like they're in tempo-run zone - basically, hard but manageable. Yet my heart rate and breathing are more like I'm on an easy run.

So my question is this - will cycling for a while at these intensities have the capability to increase my LT, even though my heart rate remains low? Or am I just talking out my arse? image


  • Your max HR will often differ between sports and therefore so will your heart rate zones.

    Cycling at the right intensity will enable you to train at your LT.  It does seem to me that when cycling leg strength is a factor in the whole equation, much less so in running.

    May be best to do a max hr test on the bike and working out your cycling zones if you'll be spending a few weeks training on it.

    Maybe a triathlete can step in here.

  • If all goes well, I should be back to running by the end of the week. Seeing as I fancy a triathlon at some point in the future, a max HR test would probably be beneficial both now and for the future. Thanks for the advice.
  • Yes, it's typical that the legs feel like they're working harder, compared to being out on a run, for the same HR.  Apart from doing a maxHR test, which I think is a good idea, you could also experiment with a less scientific approach based on perceived effort (PE).

    I've used a static bike in the gym  which has effort levels 1 - 12.  I'll find that I can keep a steady aerobic effort going at around 8-9 where maybe 9 is equivalent to what your 45 mins session is like, i.e. breathing very easy but legs working a bit harder.  (HR would be similar to easy run, or slightly lower, ~145 or 72/73% max for running).  If I fancied a harder tempo session I'd up it to 10 and either maintain same pedal rate (85 - 90) or slightly higher, according to PE, for 15 - 20mins.  HR would typically get up to 160-ish, perhaps rising slightly since it's indoors and I'm warming up (sweat puddles forming all over the floor by now!).  Try something similar, have a 40 mins session but with 15-20 in the middle on a harder setting, maintain the same pedal rate.  Legs will feel pretty heavy but you should soon get a feel for what's 'comfortably hard but hardly comfortable'.

  • Also, just to contrast that against my running intensities:

    easy run - HR 145-150
    marathon pace - high 160s
    tempo - mid 170s
    10k - mid 180s

    In other words, the sort of HR I can maintain over a full marathon feels like hard work on the bike for much more than 20 mins.  I've never done a maxHR test on the bike but I suspect I'd struggle to get close to HR I can maintain over a 10k race.  Obviously the relationship between the two will differ between individuals, according to their relative fitness between cycling and running, but I think this is fairly typical (for runners, anyway!)

  • That's really helpful, thanks Phil image

    Hopefully I should be able to get back to running tomorrow (as my tendon now feels fine) but I'll keep a copy of what you've both said as reference for when I do some X-Training in the future.
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