Power Meter Woes
#26
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
Perhaps it would help to clarify things if I explained my concern. Specifically, I'm concerned about the adverse effects of overtraining.
If my power meter is consistently under reporting my level of effort, it means that I'm consistently overshooting the target. I am far from an expert in these matters, but my guess is that the cumulative effect of constantly overreaching will interfere with my body's ability to adapt. So, for example, if I'm doing a workout consisting of several intervals at 130% of my 200 W FTP, but I'm actually doing 340 watts instead of 260, I don't think that's necessarily reason to rejoice. More likely than not, I won't finish the workout. In fact, looking back at the last six months, there are a number of the tough workouts that I did not finish. There could be any number of reasons for that, including the possibility that I'm just a wuss, but I'm just sayin'.
If my power meter is consistently under reporting my level of effort, it means that I'm consistently overshooting the target. I am far from an expert in these matters, but my guess is that the cumulative effect of constantly overreaching will interfere with my body's ability to adapt. So, for example, if I'm doing a workout consisting of several intervals at 130% of my 200 W FTP, but I'm actually doing 340 watts instead of 260, I don't think that's necessarily reason to rejoice. More likely than not, I won't finish the workout. In fact, looking back at the last six months, there are a number of the tough workouts that I did not finish. There could be any number of reasons for that, including the possibility that I'm just a wuss, but I'm just sayin'.
My experience is that virtual power on a trainer can be reasonably accurate to within +/-10% based on dozens of rides on a KK trainer with a PowerTap but it still moves around a fair amount depending on temperature, intensity of workout, temperature etc.
A stages meter will also vary significantly from day to day and intensity as the power balance in your legs changes. Bottom line is you've got two relatively coarse estimates of power and it would be difficult to draw any conclusions regarding the accuracy of either without a third independent more accurate reference.
Last edited by gregf83; 06-25-16 at 04:41 PM.
#27
pan y agua
Join Date: Aug 2005
Location: Jacksonville
Posts: 31,302
Bikes: Willier Zero 7; Merlin Extralight; Calfee Dragonfly tandem, Calfee Adventure tandem; Cervelo P2; Motebecane Ti Fly 29er; Motebecanne Phantom Cross; Schwinn Paramount Track bike
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1447 Post(s)
Liked 724 Times
in
371 Posts
If you've got a 33% difference, it would be the result of an injury, or obviously noticeable disparity. I doubt anyone has such a difference minus some obvious issue observable without a power meter.
__________________
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
You could fall off a cliff and die.
You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
#28
Senior Member
Join Date: Aug 2010
Posts: 612
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 99 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Sample of one, admittedly. I've got power data for each leg with vector, and virtual two sided power with Quark. For me, there can be 2-3% difference just riding around. That shrinks to .1-.2% on intervals or hard efforts.
If you've got a 33% difference, it would be the result of an injury, or obviously noticeable disparity. I doubt anyone has such a difference minus some obvious issue observable without a power meter.
If you've got a 33% difference, it would be the result of an injury, or obviously noticeable disparity. I doubt anyone has such a difference minus some obvious issue observable without a power meter.
2-) Even if you have a discrepancy between legs, as you said 3%, it does not matter for your training. FTP is not ePenis... As long as you get consistent readings compared to your self, you can always achieve the workout that you intend.
This whole thread is non-sense to me.
#29
Junior Member
Join Date: Jun 2016
Posts: 19
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I use a Kickr with Zwift. I visually compared the power numbers from my Stages to the Kickr. I did not notice any glaring discrepancy. I did not, however, record both and graph them. I should do that.
#30
Roadie
#32
serious cyclist
Join Date: Apr 2009
Location: Austin
Posts: 21,147
Bikes: S1, R2, P2
Mentioned: 115 Post(s)
Tagged: 1 Thread(s)
Quoted: 9334 Post(s)
Liked 3,679 Times
in
2,026 Posts
#33
Perceptual Dullard
Join Date: Sep 2009
Posts: 2,415
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 915 Post(s)
Liked 1,146 Times
in
490 Posts
2-) Even if you have a discrepancy between legs, as you said 3%, it does not matter for your training. FTP is not ePenis... As long as you get consistent readings compared to your self, you can always achieve the workout that you intend.
#34
OMC
Join Date: Oct 2010
Location: South Louisiana
Posts: 6,960
Bikes: Specialized Allez Sprint, Look 585, Specialized Allez Comp Race
Mentioned: 199 Post(s)
Tagged: 0 Thread(s)
Quoted: 461 Post(s)
Liked 116 Times
in
49 Posts
This is true if you're a pro or a trust fund baby. If you're like most of us with job/spouse/kid(s), overtraining can be an issue on fewer hours. OTOH, if you only have time to train 3-4 days/week, there's enough downtime in there to guard against overtraining.
__________________
Regards,
Chuck
Demain, on roule!
Regards,
Chuck
Demain, on roule!
#35
Banned
Join Date: May 2015
Location: North Jersey
Posts: 1,245
Bikes: 1975 Motobecane Le Champion lilac, 2015 Specialized Secteur Elite
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
If you have a job/spouse/kids and are obviously not riding a bike to make a living what are you training for to the point that you would be clueless enough to overtrain and hurt yourself?
"Sorry, I can't make it to work this week because I hurt myself due to a malfunction in my power meter"
"Sorry, I can't make it to work this week because I hurt myself due to a malfunction in my power meter"
Last edited by bakes1; 06-26-16 at 07:08 AM.
#36
Has a magic bike
Join Date: Aug 2013
Location: Los Angeles
Posts: 12,590
Bikes: 2018 Scott Spark, 2015 Fuji Norcom Straight, 2014 BMC GF01, 2013 Trek Madone
Mentioned: 699 Post(s)
Tagged: 1 Thread(s)
Quoted: 4456 Post(s)
Liked 425 Times
in
157 Posts
1. Racing. Which requires training
2. Women. Who commonly need more recovery (ie are at risk of overtraining)
3. Masters. See comment #2
While others are:
A. Judgmental twits. Pick up a mirror
#37
OMC
Join Date: Oct 2010
Location: South Louisiana
Posts: 6,960
Bikes: Specialized Allez Sprint, Look 585, Specialized Allez Comp Race
Mentioned: 199 Post(s)
Tagged: 0 Thread(s)
Quoted: 461 Post(s)
Liked 116 Times
in
49 Posts
If you have a job/spouse/kids and are obviously not riding a bike to make a living what are you training for to the point that you would be clueless enough to overtrain and hurt yourself?
"Sorry, I can't make it to work this week because I hurt myself due to a malfunction in my power meter"
"Sorry, I can't make it to work this week because I hurt myself due to a malfunction in my power meter"
Power meter malfunctions don't cause overtraining. Overtraining is the cycling equivalent of having a few beers too many and thinking you're ten feet tall and bulletproof...until reality steps in.
__________________
Regards,
Chuck
Demain, on roule!
Regards,
Chuck
Demain, on roule!
#38
Not actually Tmonk
Join Date: Jun 2007
Location: San Diego, CA
Posts: 14,121
Bikes: road, track, mtb
Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 2632 Post(s)
Liked 3,147 Times
in
1,656 Posts
One of the main perks of using a powermeter for us working stiffs is to prevent overtraining. Personally, I'm inclined to ride myself in to the ground as I like working out, and I've used the PM data to make a conscious decision to back off or ride easier in more than a few occasions.
__________________
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
#39
Senior Member
Join Date: Jul 2013
Posts: 493
Bikes: 2013 SuperSix Ultegra
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I would NOT trust a virtual power meter or estimates power meter data for reliable training data!
if you a take a given segment and ride it with a tail wind, no wind and head wind. Based on the times that you completed the segments you will get wildly different power meter numbers.
heart rate and speed can't estimate your power out numbers.
if you a take a given segment and ride it with a tail wind, no wind and head wind. Based on the times that you completed the segments you will get wildly different power meter numbers.
heart rate and speed can't estimate your power out numbers.
#40
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
I think it's common to confuse over-reaching with over-training. Overtraining is rare among elite athletes and likely even less common among recreational athletes.
Overtraining is probably the least useful justification for an accurate powermeter.
#41
OMC
Join Date: Oct 2010
Location: South Louisiana
Posts: 6,960
Bikes: Specialized Allez Sprint, Look 585, Specialized Allez Comp Race
Mentioned: 199 Post(s)
Tagged: 0 Thread(s)
Quoted: 461 Post(s)
Liked 116 Times
in
49 Posts
How does a powermeter prevent overtraining? Is there a universally applicable amount of work or stress that results in overtraining?
I think it's common to confuse over-reaching with over-training. Overtraining is rare among elite athletes and likely even less common among recreational athletes.
Overtraining is probably the least useful justification for an accurate powermeter.
I think it's common to confuse over-reaching with over-training. Overtraining is rare among elite athletes and likely even less common among recreational athletes.
Overtraining is probably the least useful justification for an accurate powermeter.
I'm with you on the overreaching vs. overtraining thing. You can't improve without overreaching. The issue occurs when you think that if a little is good then a lot is better, and also think that recovery is for wusses. Elite racers don't overtrain because they use their power meters to quantify how much work they've done, and know when they've hit their targets and stop. Almost all of them have coaches to keep them honest.
I also think that overtraining is probably not an issue with the OP, but it's good that he's aware of the possibility.
__________________
Regards,
Chuck
Demain, on roule!
Regards,
Chuck
Demain, on roule!
Last edited by revchuck; 06-26-16 at 08:36 AM.
#42
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
A power meter provides an objective measurement of how much work you're doing. I don't think there's a universally applicable amount of work that results in overtraining, since we're all different. I'm 64, and trying to maintain a training schedule meant for a guy in his 20s would wipe me out in short order. But I can still do 700-1000 TSS weeks in a training block based on my FTP and recovery needs. FWIW, my builds are based on two-week blocks; this is a common practice among Master's racers.
I'm with you on the overreaching vs. overtraining thing. You can't improve without overreaching. The issue occurs when you think that if a little is good then a lot is better, and also think that recovery is for wusses. Elite racers don't overtrain because they use their power meters to quantify how much work they've done, and know when they've hit their targets and stop. Almost all of them have coaches to keep them honest.
I also think that overtraining is probably not an issue with the OP, but it's good that he's aware of the possibility.
I'm with you on the overreaching vs. overtraining thing. You can't improve without overreaching. The issue occurs when you think that if a little is good then a lot is better, and also think that recovery is for wusses. Elite racers don't overtrain because they use their power meters to quantify how much work they've done, and know when they've hit their targets and stop. Almost all of them have coaches to keep them honest.
I also think that overtraining is probably not an issue with the OP, but it's good that he's aware of the possibility.
And I think for elite racers they don't use their powermeters to prevent overtraining, they just build downtime into their schedules. Because it's so individual there are really no guidelines for power (or work) that protect against over-training. Other markers such as resting HR being depressed, mood etc are probably better at detecting the early signs of overtraining. The accuracy of your powermeter is not important in detecting overtraining.
#43
Senior Member
Join Date: Oct 2013
Posts: 58
Bikes: 2015 Wilier Cento 1 Air, 2014 Trek Remedy 8 27.5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Exactly. Go look on Zwift and see all the jerseys 'won' by the zPower people.
I use a Kickr with Zwift. I visually compared the power numbers from my Stages to the Kickr. I did not notice any glaring discrepancy. I did not, however, record both and graph them. I should do that.
I use a Kickr with Zwift. I visually compared the power numbers from my Stages to the Kickr. I did not notice any glaring discrepancy. I did not, however, record both and graph them. I should do that.
In DC Rainmaker review there is a statement that team Sky even has similar issues against other known accurate power meters. So much so that they utilize an offset percentage for training with Stages in some cases.
Edit: This being said, it is consistent. So for training purposes as long as you stick with just Stages it should be fine.
Last edited by linsdog; 06-26-16 at 12:01 PM.
#44
Perceptual Dullard
Join Date: Sep 2009
Posts: 2,415
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 915 Post(s)
Liked 1,146 Times
in
490 Posts
Many people say this -- and they'd be right. But the real reason this is so is because training FTP is one of the least demanding applications for a power meter. That's why people have long been able to train successfully without a power meter. There are some things that are hard to do without accurate and precise measurements, but training FTP isn't particularly one of them. Many (but not all) riders aren't interested in doing those other things so for them a PM like the Stages will probably be fine. If you are interested in those other things, it won't be. No one (and that can sometimes include you yourself if you're first starting off with a power meter) can tell which group you fall into, or if your needs will stay the same over time or change.
#45
Senior Member
Join Date: Oct 2013
Posts: 58
Bikes: 2015 Wilier Cento 1 Air, 2014 Trek Remedy 8 27.5
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Many people say this -- and they'd be right. But the real reason this is so is because training FTP is one of the least demanding applications for a power meter. That's why people have long been able to train successfully without a power meter. There are some things that are hard to do without accurate and precise measurements, but training FTP isn't particularly one of them. Many (but not all) riders aren't interested in doing those other things so for them a PM like the Stages will probably be fine. If you are interested in those other things, it won't be. No one (and that can sometimes include you yourself if you're first starting off with a power meter) can tell which group you fall into, or if your needs will stay the same over time or change.
#46
Perceptual Dullard
Join Date: Sep 2009
Posts: 2,415
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 915 Post(s)
Liked 1,146 Times
in
490 Posts
Nothing's perfect, and every power meter is trying to fill a different niche, so there's room for lots of alternatives, including gateway drugs. There are also some products that have relatively high data quality but are relatively inexpensive. I put the P2M and the PT hub in that group (I haven't analyzed data from the PT chainring yet so don't know whether it would fall into that group or not). Some people, even racers, will be perfectly happy with the Stages. Some people, even non-racers, won't. Racing category actually isn't a terribly good predictor of what you'll want or need or will be able to use.
To get back to the OP, he's got two relatively low data quality devices, the Stages and a trainer, and there's no simple way for him to know which is worse -- or if the problem is his legs. In his case, the discrepancy is large enough to be obvious. There are cases where the discrepancies may be small most of the time but large under certain circumstances, and not obvious. Lots of people appear to think that if something isn't obvious it can't be important.
Last edited by RChung; 06-26-16 at 09:20 PM.
#47
Not actually Tmonk
Join Date: Jun 2007
Location: San Diego, CA
Posts: 14,121
Bikes: road, track, mtb
Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 2632 Post(s)
Liked 3,147 Times
in
1,656 Posts
How does a powermeter prevent overtraining? Is there a universally applicable amount of work or stress that results in overtraining?
I think it's common to confuse over-reaching with over-training. Overtraining is rare among elite athletes and likely even less common among recreational athletes.
Overtraining is probably the least useful justification for an accurate powermeter.
I think it's common to confuse over-reaching with over-training. Overtraining is rare among elite athletes and likely even less common among recreational athletes.
Overtraining is probably the least useful justification for an accurate powermeter.
We may be saying "over training" when we mean "over reaching", but the difference in definition between the two terms are primarily based upon an arbitrary time constant, and as such it's not useful to differentiate between them for the purposes of this conversation. Yes, of course, over training is more severe and less common.
In a separate post you stated that for most people motivation would be the limiter, but I think that there are many "Type A's" out there that don't have that problem.
I plan my weeks (or usually 3-4 week blocks) out in advance, as it's part of the fun for me. Much of of the time I will end up using the data to consciously decide to back off at some point, as I tend to overexert myself. The PM has helped me manage performance for key events and/or prevent chronic injury from overtraining, which I am susceptible to.
__________________
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
#48
Senior Member
Join Date: Jun 2008
Location: Vancouver, BC
Posts: 9,201
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1186 Post(s)
Liked 289 Times
in
177 Posts
We may be saying "over training" when we mean "over reaching", but the difference in definition between the two terms are primarily based upon an arbitrary time constant, and as such it's not useful to differentiate between them for the purposes of this conversation. Yes, of course, over training is more severe and less common.
I suspect some can simply handle more training than others, some can handle 25+ hr training weeks that might cause others to overtrain. Building a CTL of 140+ with a steady diet of threshold intervals is different than getting the same CTL with higher volume but lower intensity.
I just think power and the metrics associated with training are second order metrics for identifying over-training.
#49
Not actually Tmonk
Join Date: Jun 2007
Location: San Diego, CA
Posts: 14,121
Bikes: road, track, mtb
Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 2632 Post(s)
Liked 3,147 Times
in
1,656 Posts
No one will argue with you that it's a second-order metric, at best. It's still a useful tool in this regard IMO.
__________________
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
#50
Not actually Tmonk
Join Date: Jun 2007
Location: San Diego, CA
Posts: 14,121
Bikes: road, track, mtb
Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 2632 Post(s)
Liked 3,147 Times
in
1,656 Posts
We may be saying "over training" when we mean "over reaching", but the difference in definition between the two terms are primarily based upon an arbitrary time constant, and as such it's not useful to differentiate between them for the purposes of this conversation. Yes, of course, over training is more severe and less common.
Many cyclists in competitive circles, like rev. and myself, use the term "over training" somewhat loosely. True overtraining is quite rare and does have some physiological significance, I agree. If one tends to overreach for a few rides, say, a couple weeks' worth, when you're already fatigued in the first place, it can take a while to recover out of that TSB hole and actually be counter-productive to your long term fitness. Really it's just "fatigue", but we like to refer to it as "over training", potentially because the term has some clinical and prescriptive connotation to it. Many of the symptoms of true over training like chronic injury, illness, irritability can start to rear their ugly heads in this medium-term time view.
This is why we have felt that you are being so pedantic - because we chose to misuse the term .
__________________
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste
"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste