SRM initial questions

disgruntledgoat

Hi all, having just inherited an SRM on a second hand bike I've bitten the bullet after 15 years of training to HR and feel and decided to attempt to enter the cottage of wattage.

I bought Training and Racing With a Power Meter and am working my way through that so will probably have some further questions when I start on the field tests on the turbo next week. For now though, I'm just doing my normal wporkouts with the SRM and seeing what I notice. My initial
Couple of queries were thus

1. Do you guys set your head unit (I'm using a Garmin 500) to display actual power or an average across a time period? I found it incredibley tough to keep a consistent number on the screen with just the real time power data up there. That leads me neatly onto....

2. Do head and tailwinds have an effect on output or am I just still in the wrong mindset? My ride on weds had 2x20 mins at aerobic threshold and at my usual level of intensity I was holding between 290 and 310 watts for the most part. Yesterday I had my intervals with a strong taily and was only cranking 220 to 250. Likewise I was struggling to hold the same watts as the previous day into a big headwind on a higher intensity interval. It may be that my perceived effort is not as hard as I think, it may be tiredness but I just thought I'd ask.

3. I'm using Golden Cheetah for analysis, because I'm cheap. After I create myself as an athlete and add in weight and ftp, can I edit these later? I plan on being lighter and more powerful and couldn't see a function!

Thanks!

meanredspider

My answers to the first two

1. There was a thread on this recently. Most people seem to run 3sec average (some run 10s - though when I tried this, I think it changed too slowly)

2. To some extent, it's a mindset thing, but, as with riding downhill, riding with a good tailwind you are "chasing" the pedals a bit. Of course, changing gear helps, but I do find it harder to generate larger power numbers downhill and with a tailwind.

jgsi

Golden Cheetah: You can update your thresholds for HR and Power inTools, Options, athlete.
Bit tricky to navigate.. weight is not a metric used in GC afaik but you can still amend the number.
Some tutorials are on YouTube/Vimeo to give you some sense of it all as GC is a very powerful analysis tool.
However, it cannot like other, pay for software tools, predict the future although some packages would like to make you believe so in order to drag some pennies out of you.
http://vimeo.com/99817526

cougie

I use 3 seconds too.

I find it far easier to train with power on a turbo. Outside there are too many distractions and factors you have to allow for.

wavefront

disgruntledgoat wrote:

1. Do you guys set your head unit (I'm using a Garmin 500) to display actual power or an average across a time period? I found it incredibley tough to keep a consistent number on the screen with just the real time power data up there. That leads me neatly onto....

Like others, I use 3 + 30s av. Also having NP/AV power is very useful, and I know it's heresey around these forums but I also monitor my HR for the L1/L2 rides. These days I don't bother with speed.

disgruntledgoat wrote:

2. Do head and tailwinds have an effect on output or am I just still in the wrong mindset? My ride on weds had 2x20 mins at aerobic threshold and at my usual level of intensity I was holding between 290 and 310 watts for the most part. Yesterday I had my intervals with a strong taily and was only cranking 220 to 250. Likewise I was struggling to hold the same watts as the previous day into a big headwind on a higher intensity interval. It may be that my perceived effort is not as hard as I think, it may be tiredness but I just thought I'd ask.

I always assumed 200w should be 200w headwind or not. But as the above poster mentions, putting power down on a downhill is alot harder than on an uphill - various articles around the net that try to explain this - so it makes sense that with a big tailwind, it maybe harder to keep the power up.

That said, on the return leg of yesterdays ride, I had a very decent tailwind. I found it easier to keep a good rythm going, and seemed so much smoother in putting power down. I was +30w up on the outward leg. Maybe I wasn't using up valuable energy trying to stay upright!

I'd suggest that your power variances, are maybe more to do with tiredness/nutrition/motivation etc. Your power will vary day to day, so I now look for trends not specifics. I know my performance suffers if I lose a couple of hours sleep overnight, or I have haven't eaten correctly. Even seemingly minor life's stresses can hamper your performance.

disgruntledgoat wrote:

3. I'm using Golden Cheetah for analysis, because I'm cheap. After I create myself as an athlete and add in weight and ftp, can I edit these later? I plan on being lighter and more powerful and couldn't see a function!

Thanks!

Yup, they can be altered - you add a date when you change your ftp so all your previous data still respects your previous ftp, but new rides uploaded will respect the new ftp value. It means that all the IF, TSS etc values will remain correctly calculated.

Tools > options > Athlete > Power

Under Crtitcal power, enter the date you want to change your ftp, type in your new cp value, then hit the + button.

In this section you can alter your weight, which as has been said, is more an overal global value rather than date specific I think.

disgruntledgoat

Next dumb question

W' in GC... what is it?

FatTed

In GC
Critical power is not the same as FTP is it?
I use 3 sec average power, HR and Cadence.

Alex_Simmons/RST

disgruntledgoat wrote:

Next dumb question

W' in GC... what is it?

It's a theoretical fixed amount of energy you have available should the power demand extend above critical power.

Alex_Simmons/RST

FatTed wrote:

In GC
Critical power is not the same as FTP is it?
I use 3 sec average power, HR and Cadence.

Critical power is considered to be the power you can sustain for a long time without fatigue, and in that sense is analogous to FTP. It can be expressed in the form of an equation along these lines:

CP = MMP(duration) - W'/duration

where MMP(duration) = mean maximal power for a given duration

e.g. if you have a 5-minute MMP of 283W and a W' of 10kJ, then theoretically your CP is 250W (283 - 10000/300).

CP and W' are derived from mean maximal power data for multiple durations (at least 2) and the resulting CP and W' values are very dependent on the inputs used. It's been common in much literature and for computer models such as that used by GC to choose inputs resulting in CP values which are typically higher than FTP. Somewhere between 20-minute power and FTP.

If however you choose as inputs your mean maximal power for durations such as 5-minutes and 25-minutes, and these are reliable indicators of current maximal capability, the the resultant CP value in my experience is a good proxy for FTP.

disgruntledgoat

Thanks for the help so far guys. Another simple one... How can I delete an interval I've created by left clicking and dragging? And how can I zoom in on one, also?

markwb79

disgruntledgoat wrote:

Thanks for the help so far guys. Another simple one... How can I delete an interval I've created by left clicking and dragging? And how can I zoom in on one, also?

Go to Activity Intervals and there are the numbers. right click and then you can zoom or delete.

disgruntledgoat

Markwb79 wrote:

disgruntledgoat wrote:

Thanks for the help so far guys. Another simple one... How can I delete an interval I've created by left clicking and dragging? And how can I zoom in on one, also?

Go to Activity Intervals and there are the numbers. right click and then you can zoom or delete.

I'm my ride, i've gone to the activity menu at the top of the page, but I don't have an intervals option... And I can't see another activity button anyhwere! :oops:

EDIT: Check that, I was being thick. Thanks again.