> >
>

# Question on kJ

Notices
Training & Nutrition Learn how to develop a training schedule that's good for you. What should you eat and drink on your ride? Learn everything you need to know about training and nutrition here.

# Question on kJ

12-12-10, 07:06 PM
#1
ryanhulce
Senior Member

Join Date: Jul 2006
Location: Kokomo, IN
Posts: 536

Bikes: 2006 Cervelo Soloist Team, 2012 Windsor Kensington 8

Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Question on kJ

Trying to figure out the estimated calories burnt on training rides.

If my PowerTap says 260kJ for a 15 minute workout how many calories would that be? I weigh 160lb.

I found the following calculator: https://www.unitconversion.org/energy...onversion.html

It shows that 260kJ would would be 62.099933123 calories.

From searching on the web it seems that it should be higher than that.

Ryan
12-12-10, 07:55 PM
#2
gregf83
Senior Member

Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Quoted: 1186 Post(s)
Liked 288 Times in 176 Posts
Your body output 260kJ but it isn't anywhere close to 100% efficient; more like 18-24%. So you need to divide the 62 output Cals by your efficiency. A conservative rule of thumb is to just assume you burned the same number of Cals as the number of kJ output. In your case that would be 260 Cals.
12-13-10, 02:59 AM
#3
CdCf
Videre non videri

Join Date: Sep 2004
Location: Gothenburg, Sweden
Posts: 3,208

Bikes: 1 road bike (simple, light), 1 TT bike (could be more aero, could be lighter), 1 all-weather commuter and winter bike, 1 Monark 828E ergometer indoor bike

Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
I use average power times four to get kcal, for a full hour.

200 W avg would then mean 800 kcal for an hour, or 200 kcal for 15 minutes.

This gives you a ballpark figure, and is based on an efficiency percentage in the low 20s.
Related Topics
Forum
Replies
Last Post
tomcon
General Cycling Discussion
5
07-12-16 06:19 AM
deepakvrao
12
12-20-15 09:34 PM
ronfinch
Training & Nutrition
15
05-24-15 11:11 AM
Zedmor
Training & Nutrition
6
01-27-14 02:03 PM
2005trek1200
Training & Nutrition
11
01-09-10 12:04 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off