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  1. #1
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    More power questions

    Lets say I have a 4 hour, MTB marathon race, plenty of climbing and descending. I can average 250w for the race by taking it easy uphill and not going over a 300w threshold. Or I could hammer uphill and hit 500w while attacking the climbs, but in that last hour I might start getting tired and roll in with an average of 225w. Which is faster?

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    Too much maths for everybody's Monday morning? LOL I understand. What I'm basically trying to reason is whether an even power output is faster overall than hammering through it. Are the deleterious effects of going anaerobic going to hurt you overall in a long race?

    I've heard conflicting opinions; some say that starting a race hard will put you in the right mode and make for a quicker overall finish, others try to meter out their effort and stay aerobic. Not just 50-milers I'm interested in but XC as well. In working with my power meter it would appear that the latter option is faster.

  3. #3
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    Have you got a power meter and previous files to look at? The best test is usually to try each approach in training, look at the data afterwards and go from there.

    By threshold do you mean FTP (your best 1 hour power output)? If you have a best 1 hour power of 300 watts I suspect you may find it difficult to sustain 250 watts (83% of FTP) for four hours.

    It really depends what you mean by a hilly ride, how long are the climbs, how many are there and how many minutes of climbing in total would you be doing over the four hours? The longer and more frequent the climbs the easier you should ride up them to avoid cooking yourself. Have you read about the idea of burning matches? It's one of the concepts in the Training and Racing with a Power Meter book by Hunter Allen and Andrew Coggan

    What is a match? by Hunter Allen | TrainingPeaks

    A typical climb in the Cotswolds takes 5 to 15 minutes. They're often around a 10% gradient. Over a fairly hilly four hour ride you'd do maybe 6 climbs, say an hour of climbing in total.

    If you were riding by yourself for four hours in the Cotswolds (no drafting) the fastest way would usually be to ride well below FTP on the climbs, particularly early on. A 10 minute climb is too far to thrash up anaerobically, especially if you know that you'll have to repeat that effort multiple times. By parcelling your effort out and not over extending yourself on the climbs it means that as soon as you crest the hill you can change straight up into a big gear and get going quickly on the flat or descent without needing to spend time recovering. As an example If I pushed myself to the maximum on a single 10 minute climb I could end up needing as much as 15 to 20 minutes riding at a lower than optimal pace to try and get going again, losing more time from struggling during that 15 to 20 minutes than the few seconds I gained by going hard up the climb.

    I quite like the saying that if it feels like you're going too slowly that's about right. What feels easy whilst you're fresh at the beginning of a ride becomes extremely difficult to sustain when you're tiring later on.

    A good example of good pacing is Jordan Rapp's triathlon power meter data from the Kona Ironman. If you look at the power trace there isn't much in the way of sharp spikes as he was aiming to pace himself over the full distance. It's a marathon not a sprint.

    Rappstar's Kona power data - Slowtwitch.com

  4. #4
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    I've done both. Seems like I'm always better off going hard from the beginning to get position (definitely anaerobic), then settle into a good hard pace, then if it's a long endurance race (5-7 hours) I just survive to the end.

    In one race I found a nice group in the Pro women to hang with, stayed with them one lap (of a two lap 100K race), then i got dropped second lap hard core. As bad as I blew up, my lead was big enough in my class to maintain 3rd.

    For me, most important thing is to keep the big wheels rolling, not use the brakes, and ride the course as efficiently as possible. Super important in long races. You save tons of energy in the long run.
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  5. #5
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    More power questions

    Quote Originally Posted by Poncharelli View Post
    In one race I found a nice group in the Pro women to hang with, stayed with them one lap (of a two lap 100K race), then i got dropped second lap hard core. As bad as I blew up, my lead was big enough in my class to maintain 3rd.
    How did your average power and first lap time compare to the second lap time, before and after blowing up? In general the aim has to be to try and sustain the pace throughout.

  6. #6
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    Quote Originally Posted by WR304 View Post
    How did your average power and first lap time compare to the second lap time, before and after blowing up? In general the aim has to be to try and sustain the pace throughout.
    The "blowup" wasn't a bonk though. It was cramps from heat, and lots of back pain. Once I pushed my bike through a challenging section, then other parts of the course were shady enough to keep the heat problems away. The back pain never stopped though and i had to stop and stretch several times during the last part of race. A few guys passed me on the second lap, but luckily only 2 were from my class.

    I'm sure my second lap average speed was much slower (I don't have any data from the race), but luckily it was shorter . 100k race with first lap being ~60k and second ~40k. So probably only 30k left when my problems started. There was only 10 guys in my class so time gaps were pretty big. We all came in between 7 and 8 hours.
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  7. #7
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    More power questions

    Getting to the point where you're hurting so much that you have to stop riding altogether to stretch is quite bad.

    Do you always get back pain when riding, or is it only in certain circumstances, such as pushing big gears at high intensity? The exercise that helps my lower back most is doing 100 back extensions every day. So long as I keep that up it generally isn't an issue whilst riding.

  8. #8
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    Quote Originally Posted by chomxxo View Post
    Lets say I have a 4 hour, MTB marathon race, plenty of climbing and descending. I can average 250w for the race by taking it easy uphill and not going over a 300w threshold. Or I could hammer uphill and hit 500w while attacking the climbs, but in that last hour I might start getting tired and roll in with an average of 225w. Which is faster?
    You do what you have to do to stay with the lead group or drop the lead group. My race files show lots of big surges above threshold. I really only look at my power display if I'm riding solo & then I just keep it under threshold depending on the length of the race.

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    Quote Originally Posted by wetpaint View Post
    You do what you have to do to stay with the lead group or drop the lead group. My race files show lots of big surges above threshold. I really only look at my power display if I'm riding solo & then I just keep it under threshold depending on the length of the race.
    For a typical four hour race what sort of overall average power (as a percentage of FTP) and overall time spent above FTP are you seeing? Are you putting in big surges throughout the entire race or is the pattern more about making a selection to begin with, and then settling down to a more measured pace?

    The nice thing about power data is that you can just read these things straight off, no guesswork required.

    Looking at my four hour rides from last year about the best I could manage for a four hour hilly ride would be a miserable 73% of FTP. (186 watts average, FTP 254 watts).

  10. #10
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    Quote Originally Posted by WR304 View Post
    Do you always get back pain when riding, or is it only in certain circumstances, such as pushing big gears at high intensity? The exercise that helps my lower back most is doing 100 back extensions every day.
    Yes, always from pushing big gears and long saddle time hurts my back. The race i was talking about was unusually rocky and rough though, so that definitely didn't help. My back was messed up for a month after that 100k. One of my lower vertabrae hurt to the touch, which scared me.

    But this season my back has been pretty good!! Haven't done much back extensions but lots of other core exercises. I did a class like crossfit ("corefit" is what I call it) during the months of Nov, Dec, Jan, Feb prior to the riding season, and I believe it REALLY helped. Near zero back pain this season.

    But then again, I haven't done any long endurance races this season. Only a 100 mile road race early in the season.
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  11. #11
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    I don't have any races that long, my longest race of the year was 3 hours and normalized power was 92% of FTP, AP 72% of FTP. That race was 38 minutes anaerobic, 17min in VO2 zone.
    I tend to recover well from big efforts more than most people, although my 1-5 minute power isn't too high, I have an upward slowing power profile

    4 hour training rides with intervals, I have no problem having a NP 85% of FTP

  12. #12
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    Quote Originally Posted by wetpaint View Post
    You do what you have to do to stay with the lead group or drop the lead group. My race files show lots of big surges above threshold. I really only look at my power display if I'm riding solo & then I just keep it under threshold depending on the length of the race.
    Do you? For XC, sure. However the last marathon race I competed in I got a flat but was in good position. It was a 50 miler of two laps of 25. In my post-race finish times OCD, I noticed that the 2nd place singlespeeder started out moderate but put in two very consistent laps, catching a lot of guys and coming in only 30 seconds behind the first place guy, who'd dropped a lot of guys and tried to hang with the geared group. I think this must be the big difference between endurance and XC racing: pacing.

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    I've always understood that in any endurance event, the more evenly you can pace yourself, the faster your average speed. By "endurance", I mean any event that relies mostly on slow-twitch muscles which would definitely include an XC race. I've never understood the strategy of going extra hard in Lap 1 and then "holding on" for the rest of the race since it seems to burn more matches than is necessary. Would love to understand the theory behind it though. I can see the need to get to the single track first to avoid bottlenecks, and could see a slight psychological advantage to being out of site from competitors, but it seem that slower/steadier will be faster and that just riding your own race as steady and as fast as possible will give the best results. Passing isn't an issue on Laps 2-3 for the races I do since the field is very spread out by then and other racers are very good about letting clearly faster rides go by, but maybe that's not the case for everyone.

  14. #14
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    More power questions

    Quote Originally Posted by Poncharelli View Post
    Yes, always from pushing big gears and long saddle time hurts my back. The race i was talking about was unusually rocky and rough though, so that definitely didn't help. My back was messed up for a month after that 100k. One of my lower vertabrae hurt to the touch, which scared me.

    But this season my back has been pretty good!! Haven't done much back extensions but lots of other core exercises. I did a class like crossfit ("corefit" is what I call it) during the months of Nov, Dec, Jan, Feb prior to the riding season, and I believe it REALLY helped. Near zero back pain this season.

    But then again, I haven't done any long endurance races this season. Only a 100 mile road race early in the season.
    This is where a cadence display on the mountain bike and some bail out gears can come in handy. Whenever you catch your cadence dropping too low downshift to a lower gear and consciously keep the revs up at all times. I'll aim for above 80rpm, even on the climbs. You can get individual Ant+ cadence sensors which work with a Garmin Edge if you can't fit a GSC-10 on the frame, so that you can display and record your cadence throughout the ride. I've got a Bontrager Ant+ cadence sensor on my turbo trainer bike.

    http://bontrager.com/model/09814

    Wouldn't it make sense to keep doing the corefit classes year round, not just in the off season? If you've got back issues then a year round routine (rather than for just four out of twelve months) should help keep them in check more effectively I'd have thought.

  15. #15
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    More power questions

    Quote Originally Posted by wetpaint View Post
    I don't have any races that long, my longest race of the year was 3 hours and normalized power was 92% of FTP, AP 72% of FTP. That race was 38 minutes anaerobic, 17min in VO2 zone.
    I tend to recover well from big efforts more than most people, although my 1-5 minute power isn't too high, I have an upward slowing power profile

    4 hour training rides with intervals, I have no problem having a NP 85% of FTP
    That's about the same as I'd manage last year too (NP 82% of FTP for four hours, 208watts NP, 254 watts FTP).

    I'm really just trying to put Chomxxo's figures in his first post into context. By looking at what sort of percentage of average power or normalized power you can hold during longer training rides it can then be used as a guide for deciding pacing in longer races.

    http://home.trainingpeaks.com/articl...ess-score.aspx

    You can actually choose to have the normalized power figure displayed on your Garmin head unit now to keep an eye on throughout a ride if you wanted. I tend to just have actual power (10 second smoothing) displayed whilst riding but some people use the summary power figures also for pacing strategies.

  16. #16
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    Quote Originally Posted by WR304 View Post
    That's about the same as I'd manage last year too (NP 82% of FTP for four hours, 208watts NP, 254 watts FTP).

    I'm really just trying to put Chomxxo's figures in his first post into context. By looking at what sort of percentage of average power or normalized power you can hold during longer training rides it can then be used as a guide for deciding pacing in longer races.

    TrainingPeaks | Normalized Power, Intensity Factor & Training Stress Score

    You can actually choose to have the normalized power figure displayed on your Garmin head unit now to keep an eye on throughout a ride if you wanted. I tend to just have actual power (10 second smoothing) displayed whilst riding but some people use the summary power figures also for pacing strategies.
    Thanks for the suggestions. The numbers I was stating were hypothetical to pose the strategic question, really. My FTP is, at last estimate, 250 but I have some snap on power climbs and a good degree of endurance. With the ability to bolt but not ride away, I'm discovering that I have to manage those "matches." Probably need to work on the middle some more with 20 minute intervals.

  17. #17
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    More power questions

    Quote Originally Posted by chomxxo View Post
    Thanks for the suggestions. The numbers I was stating were hypothetical to pose the strategic question, really. My FTP is, at last estimate, 250 but I have some snap on power climbs and a good degree of endurance. With the ability to bolt but not ride away, I'm discovering that I have to manage those "matches." Probably need to work on the middle some more with 20 minute intervals.
    Have you got enough training ride files with power data to be able to look in detail at your own data yet? If you've done some four hour rides with power break them down by inserting smaller lap segments (say every 20 or 30 minutes) and compare how your performance holds up by looking at each 20 minute segment's averages in turn to see whether your power and speed is beginning to fade towards the end or not. A program such as WKO+ 3.0 or Golden Cheetah lets you do this manually post ride.

    I always like to try and write a fairly detailed note of how I felt during a ride too, with a specific time where I began to feel tired. Eg: along the lines of "felt ok for first two hours but started to feel tired after three hours as headwind on way back. Struggling in last 30 minutes, hot day didn't drink enough early on." Whenever you revisit old power files in a few years time it can be difficult to remember specific details so it helps add meaning to the data having a good note attached.

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