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    Senior Member BigSean's Avatar
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    Normalized Power-what does it really mean?

    I did a 55 mile ride today in the L3-L4 zones. My avg watts over the ride was 247, but normalized power was just under 310. Intensity had me at over 1.07 for the 3 hour ride. My FTP is set at 310, I guess I may need to raise it again. For the most part I kept my wattage between 240 and 300, bit higher on climbs and lower on decents. I didnt have anything left after about 2:45 into the ride, its been a tough week. My toughest week so far this season. So does it mean anything important?

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    The bigger the difference between Normalized Power and Average Power is an indicator of how varied your ride was. If you put out exactly 250 for the entire ride, your NP and AP would both be 250. If you put out 500 for half the time and 0 for the other half, your AP would still be 250, but your NP would be higher.

    As far as actual training usefulness, not much IMO.

  3. #3
    Quarq shill cslone's Avatar
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    Quote Originally Posted by brianappleby View Post
    The bigger the difference between Normalized Power and Average Power is an indicator of how varied your ride was. If you put out exactly 250 for the entire ride, your NP and AP would both be 250. If you put out 500 for half the time and 0 for the other half, your AP would still be 250, but your NP would be higher.

    As far as actual training usefulness, not much IMO.
    But according to people who know way more than me, it is a better indicator of the "cost" or intensity of the ride. My coach wants to know AP and NP for each ride. NP by itself is not the end all. You need to look at NP, IF and TSS for the ride to get a good picture.
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    Isaias NoRacer's Avatar
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    http://www.cyclingpeakssoftware.com/...11/defined.asp

    What are Normalized power, Intensity Factor (IF),
    and Training Stress Score (TSS)
    By. Andrew R. Coggan, Ph.D.
    One of the first things that catches the attention of any beginning power meter user is how variable, or "jumpy", their power output tends to be. This is largely due to the constantly changing resistances (e.g., small changes in elevation, gusts of wind) that must be overcome when cycling outdoors. Because of this variability, training with a power meter is not directly comparable to training using a heart rate monitor. In particular, it is very difficult (as well as counterproductive) to try to keep power constantly within a certain range, or zone, at all times during a training session. Just as importantly, this variability means that the overall average power for a ride or part of a ride is often a poor indicator of the actual intensity of the effort. This is especially true for races, since power can vary dramatically from one moment to the next as, e.g., a rider first tries to conserve energy and then attacks.

    To account for this variability, CyclingPeaks uses a special algorithm to calculate an adjusted or normalized power for each ride or segment of a ride (longer than 30 seconds) that you analyze. This algorithm is somewhat complicated, but importantly it incorporates two key pieces of information: 1) the physiological responses to rapid changes in exercise intensity are not instantaneous, but follow a predictable time course, and 2) many critical physiological responses (e.g., glycogen utilization, lactate production, stress hormone levels) are curvilinearly, rather than linearly, related to exercise intensity, By taking these factors into account, normalized power provides a better measure of the true physiological demands of a given training session - in essence, it is an estimate of the power that you could have maintained for the same physiological "cost" if your power output had been perfectly constant (e.g., as on a stationary cycle ergometer), rather than variable. Keeping track of normalized power is therefore a more accurate way of quantifying the actual intensity of training sessions, or even races. For example, it is common for average power to be lower during criteriums than during equally-difficult road races, simply because of the time spent soft-pedaling or coasting through sharp turns during a criterium. Assuming that they are about the same duration, however, the normalized power for both types of events will generally be very similar, reflecting their equivalent intensity. In fact, normalized power during a hard ~1 hour long criterium or road race will often be similar to what a rider can average when pedaling continuously during flat 40k time trial - the normalized power from mass start races can therefore often be used to provide an initial estimate of a rider's threshold power (see below).

    Although normalized power is a better measure of training intensity than average power, it does not take into account differences in fitness within or between individuals. CyclingPeaks therefore also calculates an intensity factor (IF) for every workout or time range analyzed. IF is simply the ratio of the normalized power as described above to your threshold power (entered under "Athlete Settings" at your "Athlete Home"). For example, if your normalized power for a long training ride done early in the year is 210 W and your threshold power at the time is 280 W, then the IF for that workout would be 0.75. However, if you did that same exact ride later in the year after your threshold power had risen to 300 W, then the IF would be lower, i.e., 0.70. IF therefore provides a valid and convenient way of comparing the relative intensity of a training session or race either within or between riders, taking into account changes or differences in threshold power. Typical IF values for various training sessions or races are as follows:

    Typical IF values for various training sessions or races are as follows:
    • Less than 0.75 recovery rides
    • 0.75-0.85 endurance-paced training rides
    • 0.85-0.95 tempo rides, aerobic and anaerobic interval workouts (work and rest periods combined), longer (>2.5 h) road races
    • 0.95-1.05 lactate threshold intervals (work period only), shorter (<2.5 h) road races, criteriums, circuit races, longer (e.g., 40 km) TTs
    • 1.05-1.15 shorter (e.g., 15 km) TTs, track points race
    • Greater than 1.15 prologue TT, track pursuit, track miss-and-out
    Note that one particularly useful application of IF is to check for changes in threshold power - specifically, an IF of more than 1.05 for a race that is approximately 1 hour in duration is often a sign that the rider's threshold power is actually greater than that presently entered into the program. Thus, by simply examining a rider's IF for various events during the course of a season, increases or decreases in threshold power can often be revealed without the need for frequent formal testing.

    While exercise intensity is clearly an important factor in determining the type and magnitude of physiological adaptations to training, exercise frequency and duration - which together determine the overall training volume - are important factors as well. However, there is obviously an interaction between training intensity and volume, i.e., at some point as intensity goes up volume must come down, and vice-versa, or else an you will become overtrained. To quantify the overall training load and hopefully help avoid such a situation, CyclingPeaks uses your power data to calculate a training stress score (TSS) for every workout, and provides a graphical summary of your recent TSS on your Athlete Home page. TSS, which is modeled after Dr. Eric Bannister's heart rate-based training impulse (TRIMPS), takes into account both the intensity (i.e., IF) and the duration of each training session, and might be best viewed as a predictor of the amount of glycogen utilized in each workout. Thus, a very high TSS resulting from a single race or training session can be used an indicator that one or more days should be scheduled. For example, while individuals will tend to differ in how much training they can tolerate, depending on their training background, natural abilities, etc., the following scale can be used as an approximate guide:

    The following scale can be used as an approximate guide:
    • Less than 150 - low (recovery generally complete by following day)
    • 150-300 - medium (some residual fatigue may be present the next day, but gone by 2nd day)
    • 300-450 - high (some residual fatigue may be present even after 2 days)
    • Greater than 450 - very high (residual fatigue lasting several days likely)
    As well, the cumulative TSS per week or per month can be used help identify the maximum intensity and volume of training that still leads to improvements, rather than overtraining.

    By allowing convenient tracking of normalized power, IF, and TSS for each workout and over time, CyclingPeaks provides both individual athletes and coaches a powerful tool for analyzing the enormous amount of data gathered by training with a power meter. The results of such analyses can then serve as the springboard for improvements in training and, ultimately, race performance.
    2009 mileage = 14,738 miles; 2010 mileage = 15,234 miles; 2011 mileage = 17,344 miles; 2012 mileage = 11,414 miles; 2013 = 12,169

  5. #5
    部門ニ/自転車オタク NomadVW's Avatar
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    +1
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    Mmmmm Donuts! FatguyRacer's Avatar
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    I gotta get Cycling Peaks software. Polar software is great, but leaves alot to be desired for power analysis.
    John

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    Senior Member BigSean's Avatar
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    That helps, thanks. So this was all rolling terrain, with headwinds on the return ride(didnt start blowing until I had turned towards home). Based on the TSS scores (mid 350's), although it didnt feel like it at the time, it was a tough ride. It sure feels like it now.

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    Senior Member BigSean's Avatar
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    Quote Originally Posted by FatguyRacer View Post
    I gotta get Cycling Peaks software. Polar software is great, but leaves alot to be desired for power analysis.
    Im sure when I actually understand what all of it means I will enjoy it even more.

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    Mmmmm Donuts! FatguyRacer's Avatar
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    Quote Originally Posted by BigSean View Post
    Im sure when I actually understand what all of it means I will enjoy it even more.
    Im with you. At this point, I know my Polar meter works, it's correctly setup per the results of my calibration test protocol (consistent power readings at the same speed for all gears large and small rings) yesterday and I have the Coogan/Hunter book. So far i think i have a handle on it. Right now my only concern is doing the tests for FTP and what not. This is my rest week so i'll be tackling that on Saturday or Sunday. I also need to do the hill test to see if my power numbers are reading high/low. I might need to raised that sensor up.
    John

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    Senior Member BigSean's Avatar
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    Quote Originally Posted by FatguyRacer View Post
    Im with you. At this point, I know my Polar meter works, it's correctly setup per the results of my calibration test protocol (consistent power readings at the same speed for all gears large and small rings) yesterday and I have the Coogan/Hunter book. So far i think i have a handle on it. Right now my only concern is doing the tests for FTP and what not. This is my rest week so i'll be tackling that on Saturday or Sunday. I also need to do the hill test to see if my power numbers are reading high/low. I might need to raised that sensor up.
    The best part about training with the power meter is my numbers continue to increase every couple of weeks. Partly because I had a rough winter and didnt get steady training, but also because now Im on a schedule and all my rides are monitored by the power meter. My rides are much more intense now, and the recovery rides are much mellower. Next week is a rest week, right now Im feeling a bit worked as the books all say you should be going into week three. I also did my first VO2 workouts last week, they are very painful and tiring.

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    Isaias NoRacer's Avatar
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    Quote Originally Posted by FatguyRacer View Post
    Im with you. At this point, I know my Polar meter works, it's correctly setup per the results of my calibration test protocol (consistent power readings at the same speed for all gears large and small rings) yesterday and I have the Coogan/Hunter book. So far i think i have a handle on it. Right now my only concern is doing the tests for FTP and what not. This is my rest week so i'll be tackling that on Saturday or Sunday. I also need to do the hill test to see if my power numbers are reading high/low. I might need to raised that sensor up.
    I need to pick up Dr. Coggan and Mr. Allen's book too, but the stuff I've found online has been decent as well.
    2009 mileage = 14,738 miles; 2010 mileage = 15,234 miles; 2011 mileage = 17,344 miles; 2012 mileage = 11,414 miles; 2013 = 12,169

  12. #12
    Mmmmm Donuts! FatguyRacer's Avatar
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    Quote Originally Posted by BigSean View Post
    The best part about training with the power meter is my numbers continue to increase every couple of weeks. Partly because I had a rough winter and didnt get steady training, but also because now Im on a schedule and all my rides are monitored by the power meter. My rides are much more intense now, and the recovery rides are much mellower. Next week is a rest week, right now Im feeling a bit worked as the books all say you should be going into week three. I also did my first VO2 workouts last week, they are very painful and tiring.
    I like how that works out. I just did 3 straigt weeks with only one day off and after yesterdays 2 hr roller session I was ready to quit. After the meter test, i did some 1 min maximal efforts in the 2nd hour. I got thru 3 1/2. The goal was to do as many as I could over the course of a 1/2 hr with 5 min rest periods between them. On the forth one, the body was willing but the mind was weak. Resulting analysis of the data showed that i could have done it had I had the will to endure the pain. The graph showed that every interval was progressivly stronger and faster. Did you know you can crank out close to 40 mph on rollers?
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  13. #13
    Senior Member BigSean's Avatar
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    Quote Originally Posted by FatguyRacer View Post
    I like how that works out. I just did 3 straigt weeks with only one day off and after yesterdays 2 hr roller session I was ready to quit. After the meter test, i did some 1 min maximal efforts in the 2nd hour. I got thru 3 1/2. The goal was to do as many as I could over the course of a 1/2 hr with 5 min rest periods between them. On the forth one, the body was willing but the mind was weak. Resulting analysis of the data showed that i could have done it had I had the will to endure the pain. The graph showed that every interval was progressivly stronger and faster. Did you know you can crank out close to 40 mph on rollers?
    I have noticed that on some days when I think my legs feel heavy and tired, I am actually stronger then previous rides. This tends to boost confidence and motivate me even more. On yesterdays ride I really started to fade after 2.5 hours, I thought I didnt eat enough. But when I down loaded the power profile I realized that I had kept the intensity up for a solid 2 hours, and I was just flat out tired from the work. Cant waiit to re-test after my rest week. I believe a new FTP in in reach.

  14. #14
    Carpe Diem bdcheung's Avatar
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    Quote Originally Posted by BigSean View Post
    I did a 55 mile ride today in the L3-L4 zones. My avg watts over the ride was 247, but normalized power was just under 310. Intensity had me at over 1.07 for the 3 hour ride. My FTP is set at 310, I guess I may need to raise it again. For the most part I kept my wattage between 240 and 300, bit higher on climbs and lower on decents. I didnt have anything left after about 2:45 into the ride, its been a tough week. My toughest week so far this season. So does it mean anything important?
    IF of 1.07 for 3 hours would indicate an underestimated FTP.
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    Senior Member BigSean's Avatar
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    Quote Originally Posted by bdcheung View Post
    IF of 1.07 for 3 hours would indicate an underestimated FTP.
    or an increasing FTP.

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    部門ニ/自転車オタク NomadVW's Avatar
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    If you're doing 1.07 for three hours, you've probably been underestimating for a while.
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    Isaias NoRacer's Avatar
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    Quote Originally Posted by FatguyRacer View Post
    Did you know you can crank out close to 40 mph on rollers?
    Ya mean like this?



    My problem was the rear tire started to slide out to the side.
    2009 mileage = 14,738 miles; 2010 mileage = 15,234 miles; 2011 mileage = 17,344 miles; 2012 mileage = 11,414 miles; 2013 = 12,169

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