quick starter lesson

Discussion in 'Power Training' started by vspa, Oct 7, 2012.

  1. vspa

    vspa Active Member

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    please someone state the basics of power training, do you still get cadence, speed and heart rate readings ? why is power so accurate to different trainings scenarios ? which one is more convenient: hub, chainring or pedals (the new one by polar and look) ?
     
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  2. RapDaddyo

    RapDaddyo Active Member

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    Get a copy of Training and Racing with a Power Meter by Hunter Allen and Andrew Coggan, about $17 on Amazon.com.
     
  3. daveryanwyoming

    daveryanwyoming Well-Known Member

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    Yes, read Hunter and Coggan's book. You can also start with a quick summary here: http://home.trainingpeaks.com/power411.aspx

    But in terms of your questions
    All the commercially available power meters display and record cadence and speed and support HR monitoring and recording if you wear an appropriate HR strap.


    Power is what propels the bike, not HR, not even cadence depending on gear choices and not pedal force again depending on gear choices and cadence. Power is what you want to improve and there's an old adage that applies to many things that basically says "what gets measured gets improved'. You can measure HR to assess workout quality and pacing in some situations (not very good for short intervals or bursty high power work) but you can't really 'improve' HR, your HR at LT or FTP or VO2 Max pacing is basically what it is beyond some early adaptations and long term aging processes. But at that same HR good training coupled with sufficient recovery can lead to dramatic increases in power and again that's what drives the bike. So measure the thing you're most interested in improving not secondary or tertiary things that aren't directly related.

    In scenario terms:

    - Peak power or very short duration power in sprinting situations and how you best generate that power (e.g. high cadence, lower gearing vs. high gear, lower cadences) is very useful information that can help riders learn to jump quicker and sustain higher speed sprints

    - In short interval situations power is a very accurate reflection of the work performed. HR basically doesn't respond quickly enough for things like one or two minute anaerobic efforts.

    - HR has inherent averaging and long term lag and drift characteristics that can lead to suboptimal interval or TT pacing. It takes five to seven minutes for HR to reach the average during a 20 minute iso-power interval, if you try to hit the target HR zone too quickly you'll have to overcook the start which usually leads to fading before the finish. Similarly HR will drift upwards during long iso-power efforts. If you try to artificially cap HR to a tight pre-defined training zone you'll have to back off power in the final minutes to offset HR drift, again that's suboptimal pacing for training intervals or races.

    - Energy in kj burned is directly related to power and can be accurately measured with a power meter. With a very small variation due to an individual rider's Gross Metabolic Efficiency that energy burned in kj is a very accurate estimate of dietary calories burned during exercise and far more accurate than on line lookup tables or HR based calorie estimators.

    There's more but that's a pretty good start.


    It depends on your situation and finances. Crank based PMs are great in terms of allowing the use of any wheelset and if it's a modern crank design (like Shimano Hollowtech or SRAM) then swapping cranks between bikes pre-equipped with suitable bottom brackets only takes a minute or two. Hub based designs are probably the easiest if you have multiple bikes but not so great if you run different wheelsets for different conditions like deep wheels or a disc on race days. I wouldn't be an early adopter of pedal based systems and would give those technologies time to work out any kinks.

    I ran Ergomo of about six months when I started using power and it was a nightmare of drifting values and no way to objectively check accuracy. I went to PT hubs for a couple of years and was very happy but as I accumulated more and more PT wheelsets I decided the economics weren't working well for me. For the past four seasons I've been running wired SRM units that I've picked up on the used market as a lot of folks upgraded to wireless. That has been very cost effective and I like the flexibility and the ability to use any wheels. If I had to buy these new I'd probably still be using PT hubs as they're great but all in all I'm glad I switched to SRM as it's been very trouble free and easy to field calibrate with known weights so I'm very confident about the accuracy.

    There's no magic in a PM, it's just an instrument to measure the work you've performed. That said, the PM can give you some very objective feedback on your training and racing and really pinpoint what is or is not working for you. You've still got to do the work and sometimes what the PM tells you isn't much fun to see like when your power for a certain type of interval or racing situation is lower than you'd hoped but that is also information that can tell you a lot about recovery and freshness that may help you manage your overall plan or remind you to dig deeper on your focused training days.

    -Dave
     
  4. vspa

    vspa Active Member

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    ok another basic question please, 100 watts (at 130 bpm) in a treadmill = 100 watts (at 130 bpm) cycling ? or 100 watts in a treadmill = 100 watts cycling (with varying bpm)
     
  5. daveryanwyoming

    daveryanwyoming Well-Known Member

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    Well assuming the treadmill power reading is accurate, 100 watts equals 100 watts or 100 joules of energy burned per second or 360 kj per hour of energy burned. IOW, 100 watts defines the energy burn rate regardless of the workout device and among other things that implies roughly the same caloric burn rate assuming your gross metabolic efficiency is the same or very close for both activities.

    But I'm guessing your question is more along the lines of whether those two activities performed at the same power will yield the same training results for one sport or the other. Unless your training goal is pure energy burning for something like weight management, the general answer is no due to lack of specificity. IOW, running and cycling engage your muscles differently and training in one mode vs the other will yield different results at least in fairly well trained athletes. Cross training is the most effective for folks with the least sports specific training. If you're just starting to get active then you'll likely get a lot of benefit from almost any cardio cross training activity, but as you develop more and more sports specific fitness you likely won't see as much benefit from training in other sports that engage your muscles differently. So from the perspective of an active cyclist, 100 watts on the treadmill will not yield as much sports specific training benefit as the same power on the rowing machine or treadmill even though you're burning energy at the same rate.

    Still there are plenty of good reasons to cross train including variety during the off season (I like nordic skiing for that reason), availability of equipment (if you don't have access to a bike say while on a business trip a treadmill, elliptical or rowing machine beats the heck out of doing nothing) or for maintaining general (not sports specific) fitness (when I only ride the first long hikes, or mountaineering trips that include downhills can give my legs fits with the eccentric muscle contractions as the bike doesn't work muscles in those ways so if I want to avoid that I'll hike or run a bit in addition to cycling).

    So, yes at one level the watts are describing the same thing, an energy burn rate in joules per second. But no for an experienced cyclist running won't be as sports specific as cycling and vice versa for an experienced runner jumping on an exercise bike.

    -Dave
     
  6. vspa

    vspa Active Member

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    so i buy the powermeter, set it up and configure, and then establish the LT4 zone (anaerobic threshold) or FTP by doing a 60 minute climb, or a race like club-ride or anything where i should perceive that i am in fact riding at my threshold. After that ? you set the number on the powermeter head unit and "voila", i get all the other LT zones as percentages of LT4 ? p.s. i spotted a SRM PC7 head unit in EBAY at half the price, but the usb cable and charger were missing, can you get those elsewhere ? i couldn't ask questions directly to the seller in EBAY ? seller recommended e-mailing him for shipping matters, but his email is not visible lots of questions... thank you !
     
  7. frost

    frost New Member

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    To be exact those are not "LT-zones" but usually L=Level or Z=Zone abbreviation used, eg. L1, L2, L3 or Z1, Z2... etc. Doesn't really matter and might sound picking but since LT is very commonly used abbreviation for Lactate Threshold and some testing systems recognize two different Thresholds name LT1 and LT2 this might cause confusion if you name levels LT..

    But yes, more or less as you describe. Test your FTP and set it in powermeter head, training software, spreadsheet or just your pocket calculator and you will get the zones/levels calculated. Then don't get too fixed to zones understanding that in your body there really are no tight zones or categories but this is just a descriptive system to facilitate the communication and thinking.

    Read more here http://home.trainingpeaks.com/articles/cycling/power-training-levels,-by-andrew-coggan.aspx or as suggested get 'Training and Racing with Power Meter' for full text.

    There's been wired SRM's for a very good price in Ebay. If I were on a market for a first powermeter I would definately look for used wired versions which really don't lack in functionality at all but go for at least half the price. Also some good priced PowerTaps.

    I have seen SRM accessories available in Ebay separately but you might also contact SRM/Distributor about those.

    Edit: PC7 cable looks standard Mini USB to me which you can get from practicly any computer/electronics store for a pocket money. There's a good change that you already have one with mobile phone, digital camera, etc.
     
  8. An old Guy

    An old Guy Member

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    Power training as practiced by most people is based on myth. (Not just myth but on training of professionals who seem to take a lot of PEDs. Unless you include PEDs in your training, myth is about all there is.) (PEDs performance enhancing drugs.)

    I have a power meter - PowerTap. I use a combination of power and heart rate to direct my training. My goal is to increase my power/heart beat ratio. What I do seems to work. (If I was ambitious, I would improve faster but ...)

    ----

    Power output is not accurate for training. There are indications that power output falls 1% for each degree above 70 degrees F. (My records seem to support that.) Which means that your FTP is 30% or so lower at 100* than it is at 70*. That amounts to a massive training error.
    .
     
  9. fergie

    fergie Member

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    What a load of nonsense. Do you really derive satisfaction from posting such incorrect and baseless information here.
     
  10. alienator

    alienator Well-Known Member

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    It's not massive training error if you account for it, and it's easy enough to test and adjustment to a theoretical 1% power loss per each 1° over 70°. The myth claim is only your opinion, as is your claim about power output no being accurate for training.
     
  11. bgoetz

    bgoetz Member

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    Yes! I was wondering when AOG was going to show up and spew more crap, things were starting to get boring. Please explain how power drops with temperature increase? A watt is a watt regardless of any condition. Now what you are experiencing is the bodies response to the increased temperature expressed through an increase in PE and HR. This only supports the argument that training with power is more accurate because it is a constant. Sure if it is real hot and I don't properly prepare myself for the conditions, I won't put out the same power, but I have had my average HR vary significantly during workouts of the same duration and average power. Further more, average power of intervals will be less if you are fatigued, does this mean power is incorrect, no, it means I am fatigued. Using HR, how do you determine training stress during a hard group ride/race? My HR is so delayed that I could go a whole 2hr crit @ basically my LT HR. does this mean I was riding at LT for two hours of course not.
     
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