20 min TT: indoor or outdoor

[VO2max]

Do you perform 20 TT indoor or outdoor to get FT (functional threshold). I do not seem to be able to produce the same watts on indoor trainer than outdoors.

The reason I ask is that during the winter month I will do most training on indoor trainer. IF I work on outdoor FT then I will die on indoor trainer. If I use indoor trainer watts and I will ride when weather in the cape permit during winter months then I might be way under.

I ask the question here as there might be other hubbers that have same problem.

Anyone of you that find that you cannot produce the same power on indoor trainer compared to outdoor test.

[Guest Michelle]

I have the same problem

Maybe do both?

 

Umm Bruce?  I think I asked you the same question a while back... help!

[BikeMax]

It is a common (and much discussed) concept - many people do experience difficulty putting out the same power indoors as outdoors.

 

Most people also find that the gap closes with more indoor training.

 

My advice is to test indoors for zones indoors and test outdoors for zones outdoors.

 

Here is a link to a thread I posted on Cycling forums a while back - lots of info and opinions;

 

http://www.cyclingforums.com/t343971.html

 

 

[VO2max]

Thanks Bikemax

 

I checked the thread but I see it is quite a long one, so I will read it a bit later.

 

Appreciate the info

[bruce]

 

 

Yes, there is a helluva lot of debate around this topic.  I have my own theories which one day I will find out a way to test, as well as some new ones that come from some of Tim Noakes' Central Governor model for fatigue.

 

That said, the following factors seem to influence your ability to produce the same power indoors and outdoors:

1. Motivation/stimulation - iPod with your favorite form of upbeat music, computer based trainers that allow you to race against yourself, or over a course etc are all ways of improving the indoor trainer experience.

2. Temperature/ventilation.  Having read recently some of Tim Noakes' theories, it appears that RPE is quite closely related to core body temperature.  His belief is that is body temperature increases, rate of perceived exertion for the same power output also increases because the brain is trying to protect the body from overheating.  So, it is very important to have a really good fan to cool you while riding.  I also freeze a bottle of water overnight and drink it as it melts.  As body temperature goes up blood is diverted to capillaries in the skins to try cool the body (water cooling effect).  This blood is then not available to provide oxygen to working muscles.

3. Inertial Load.  This is a very technical issue, but it revolves around the fact that the flywheel of an indoor trainer does not provide the same intertia as a cyclists body weight when riding outdoors.  This inertia is stored energy, which is released during the dead spots of the pedalling cycling.  On an indoor trainer, the deadspots are accentuated and the torque that the muscles must produce to achieve the same power is increased - it is believed that this fatigues the muscles as well.

 

So, ways to overcome this:

1. Find a way to be stimulated during indoor training - I use a computrainer, which allows me to race against a previous performance, as well as music.

2. Get a big fan, or two!!  Have a bottle of ice water, which helps significantly in cooling the core body temperature.

3. Get a good indoor trainer with a heavy flywheel.

4. Get used to riding indoors.  It takes a little while but slowly it becomes easier to reproduce outdoor power - certainly to within the target training zone.

 

bruce2007-03-23 05:36:55

[Guest Big H]

I used to do races at a HR ave of 85-89% of max. I could never achieve that in the Spinning class. I posed this question on one of the Yank forums. Same feedback as above from Bruce. The added movement on a moving bike as opposed to the spinn bike. Freeflow of air means you do not heat up that much and a nother factor is extra adrenalin supplied. The "danger" and excitement of racing leads to extra production of adrenalin thus raising thersholds. Etra ventilation on the spinner helped but I still could not achieve the same HR ave.