Strava
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IMO there is no such thing as a dangerous segment; there are, however, dangerous riders. These riders will be dangerous and inconsiderate irrespective of the roads they ride. No segment requires you to break posted traffic laws. I understand that when I see one of our local segments of the annual stage race (that takes place each Labor Day weekend) it is posted under race conditions (posted/closed roads, police escorts, etc.). I don't take that as "green light" during my rides to power through it as fast as I can, beyond safety conditions, beyond my abilities. Either I'll be safe and ride another day or I'll be an idiot and hurt/kill myself or someone else.
Full disclosure... I only bother with climb segments (I enjoy climbing more than descending) or segments that form routes I use to track my overall development.0 -
As a general rule, I only aim for KOM for uphill segments or flat segments that don't have stop signs or red lights on them. I'm not going to risk my own life to beat someone.0
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I don't worry about KoM's - frankly, I'm so slow they're something of an irrelevance - I have a couple of "personal segments" set up so that Strava will tell me when I've done a quick one on my regular training loop, but if anyone with half an ounce of ability on the bike rode those segments, I'd be 20-30 minutes adrift of their time :laugh:0
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The Calorie calculation on strava seems to be off from all the other gps programs. I use endomondo on my android phone and then upload to strava.0
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The Calorie calculation on strava seems to be off from all the other gps programs. I use endomondo on my android phone and then upload to strava.
Strava isn't too bad IMHO. A lot of apps/site over-estimate hugely (including MFP!)0 -
I find Strava to be around 10% higher FOR ME, than the readings I get from my NewLeaf calibrated Garmin 800 and Powermeter setup, which is probably as close as you'll get on a day-to-day basis without riding all your miles on an ergometer!
I'm not saying it's 10% high for everyone - or anything of the sort - calorie calculations are all pretty much down to your own personal level of muscular efficiency. We can pretty much definitively measure the wattage we're producing given the correct kit. We know how long we've ridden, so we can work out how many Joules of energy we're consuming (1 joule = 1 watt/second). We can from that figure of joules get the calories used to move us along. (1 joule = 0.239005736 calories) What we CAN'T easily derive, is how efficient is our "human engine" - i.e. for every calorie of effort that goes through our rear wheel, how many does the body ACTUALLY burn. Some is wasted in heat, some is wasted in bobbing around on the bike, some is wasted in producing loads of snot, or in clearing the same... This is where ALL the websites fall down to a greater or lesser degree - because they HAVE to make certain assumptions as to that Metabolic Efficiency factor.
For example - with todays ride - http://app.strava.com/activities/40860340 as the raw data...
Energy consumption (as logged via the GPS) - 1260kj
Calorific value thereof = 1260 * 0.2339005736 = 294.714kCals
Quoted Calorie figure from Strava = 1405kCals
which say's Strava reckons I'm around 21% Metabolically efficient. (294.714/1405 = 0.20976085ish). I've Applied this calculation to half a dozen of my outdoor rides and the maths have been pretty much constant, so, my best guess is, that for me, at my particular weight and height, they reckon i'm 21% metabolically efficient.0 -
continued from above:
So - Strava reckon i'm 21% efficient then... Doing the same mathematics with the Garmin recorded results...
Energy consumption (as logged via the GPS) - 1260kj (same, obviously)
Calorific value thereof = 1260 * 0.2339005736 = 294.714kCals
Quoted Calorie figure from Garmin/NewLeaf Calculations = 1263kCals
So, the Garmin 800/New Leaf Profile has me pegged at 20.95914% for this ride - pretty close to the 21% strava has come up with I'd say.
Where the NewLeaf approach is a bit more accurate, however, is that it actually measures (via respiratory gases) how efficient you are, and how many actual calories you're burning at a range of Heart Rates. At the end of the test, you get a bunch of files, including one that you upload into the Garmin, which tells your how many Calories you burn at a given HR - it's just a XML file, and easy enough to understand, but here's the meat-and-veg of it...
I honestly don't know where they conjured up data for the Heart rates above 180 from - I peaked out at 178, so I can only assume that even here there's a certain degree of "interpolation" or "scientists guessing" going on... frankly, it's academic, as I'm sure as hell not going to be hitting HR's like that anyway :laugh:
What I did find interesting (in a geeky kind of way) was that if you look at the Fat Calories column, as soon as I hit 130bpm, I definitely get out of the "fat burning" zone, and the proportion of energy from blood/muscle glycogen goes way, way up...
(there's a fairly thorough article on the NewLeaf testing here - http://www.dcrainmaker.com/2012/01/look-at-testing-with-new-leaf-fitness.html - in case anyone wonders what the hell I'm wibbling on about!)0 -
I've actually "run the numbers" for a few of the Stravisti that I'm following, and it seems that we keep getting to that 21% figure... that's for males and females btw...0
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This is really interesting so I ran a few calculations too on my recent 3 rides...
20.982 %
20.9795%
20.9808%
Not that I know what this means...0 -
As a general rule, I only aim for KOM for uphill segments or flat segments that don't have stop signs or red lights on them. I'm not going to risk my own life to beat someone.
There is a downhill in Nottingham where the KOM is over 30MPH. Considering the way that the light system in the centre is set up the only way you can beat it is with a car, or running every single red light!0 -
This is really interesting so I ran a few calculations too on my recent 3 rides...
20.982 %
20.9795%
20.9808%
Not that I know what this means...
plus all the other stuff above, off to spend time with those numbers!!!! Will check those next week when got my analysis head on!!!0 -
... Metabolic Efficiency factor....
I promised myself that I wasn't going to go there because it would take a huge post to describe.... glad you went there so I don't have to :-)0 -
I promised myself that I wasn't going to go there because it would take a huge post to describe.... glad you went there so I don't have to :-)
I was bored... did I get it near enough correct ??0 -
I was bored... did I get it near enough correct ??
For my 3rd-grade understanding of it, it sounded right :-)0 -
The errors you saw were likely from your tracking device and not from the strava app. Super competitive people LOVE strava - and I am one of them! http://app.strava.com/athletes/126522
You don't have to be super competitive to LOVE strava....I love it and enjoy tracking my own progress0 -
Strava has definitely changed the way I bike...love to improve on segments! http://app.strava.com/athletes/17314280
