HOT: Active* forum members generally gain 5% discount at starbike.com store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Articles FAQ Contact About




Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Wed May 13, 2015 8:29 am 
Offline

Joined: Sat Jul 19, 2014 10:15 pm
Posts: 71
G'day all,

I have a question regarding how power readings are affected on inclines/declines?

I'm using a power2max and my assumption is that I always read higher when climbing or sprinting uphill? (20min power is about 70watts higher when climbing). Max power has only been achieved uphill.

Is there any scientific text that explains why this happens?

I can assume gravity has an effect helping create more resistance helping you torque the pedals better (very different to wind resistance) when climbing so a higher FTP?

Having said that - I have had some good power readings in slight descents...

Or is all this my imagination...


Top
 Profile  
 
PostPosted: Wed May 13, 2015 9:10 am 
Offline
User avatar

Joined: Sun Sep 28, 2014 11:53 am
Posts: 92
When you’re time trialing, once you’re up to speed you’ve got a lot of energy in the system and as the pedals go around they’re merely topping up the energy required to sustain a fast pace. In a TT (high speed, flat road, high kinetic energy), the duration that your muscles have to fire is very small. You’re basically firing the muscle for a very short period of time every pedal stroke, but very quickly.

When you’re pedaling up a climb (low kinetic energy, traveling slowly, gravity holding you back), your legs impart force on the pedals for a much longer duration throughout the stroke, even though your cadence might the same as when TT’ing.

In short, your motor patterns are significantly different between time trialing and climbing.

http://cyclingtips.com.au/2013/09/climb ... -affected/


Top
 Profile  
 
Posted: Wed May 13, 2015 9:10 am 


Top
  
 
PostPosted: Wed May 13, 2015 9:46 am 
Offline

Joined: Sat Jul 19, 2014 10:15 pm
Posts: 71
Excellent thats the sort of article I was after.

Where does sprinting fall into that with the KE? as it's a 5-20sec max effort?


Top
 Profile  
 
PostPosted: Wed May 13, 2015 10:03 am 
Offline
User avatar

Joined: Sun Sep 28, 2014 11:53 am
Posts: 92
I know it feels like it is a much longer pedal stroke when sprinting but from everything I have read, it certainly states the Sprinting = Fast Twitch Effort. . ie; "pedals go around they’re merely topping up the energy required to sustain a fast pace". Though, I am not an authority on this.

an sprint uphill, a la Purito, well, I think this is stiil fast twitch. Again, I don't know for sure.

or maybe I got this all mixed up??? :doh: It is a very good question and I hope someone else chimes in.


Top
 Profile  
 
PostPosted: Wed May 13, 2015 2:59 pm 
Offline
User avatar

Joined: Sat Aug 29, 2009 4:30 pm
Posts: 1642
I have noticed the same phenomenon for a long time.
I still don't understand exactly why, except to say that the load and momentum conditions are different. Some people seem to be able to put out similar power levels on flats and climbs, but I can't.
Sometimes I think that maybe it is entirely mental: On a climb, if you relax for an instant your speed immediately and dramatically falls. On the flats, I can back off a little without really noticing a change in speed, so I just keep gradually backing off a little so it doesn't hurt so bad. ????


Top
 Profile  
 
PostPosted: Thu May 14, 2015 9:36 am 
Offline

Joined: Sat Jul 19, 2014 10:15 pm
Posts: 71
For me it's a significant difference, then again I have a bit to go to climb like an A grader and a bit to go to sprint and TT like a pro so... oh well.

But still curious to the physics behind it all


Top
 Profile  
 
Posted: Thu May 14, 2015 9:36 am 


Top
  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 


Who is online

Users browsing this forum: ewwhite, Google [Bot], hornedfrog, MSNbot Media, Nicos, rmerka, stevec1975, wingguy, Yahoo [Bot], Zak and 89 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Need Weenie Help - Zero Gravity brakes

in Road

Tippster

2

622

Wed Nov 19, 2014 9:40 pm

Tippster View the latest post

There are no new unread posts for this topic. SRM power meter question

in Road

Iamspecialized

2

542

Tue Jul 29, 2014 9:28 pm

Danza View the latest post

There are no new unread posts for this topic. New group set, new power meter?

in Road

naylor343

5

1399

Wed Jul 16, 2014 9:57 pm

dunbar42 View the latest post

There are no new unread posts for this topic. Power meter dilemma

[ Go to page: 1, 2 ]

in Road

mattjevans

23

2577

Thu Apr 23, 2015 8:52 am

mattjevans View the latest post

There are no new unread posts for this topic. Is the c59 an improvement on the Extreme Power?

in Road

wilwil

2

557

Mon Sep 08, 2014 1:48 am

mnmasotto View the latest post


It is currently Wed May 27, 2015 9:36 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB