1kTT Posted October 30, 2007 Posted October 30, 2007 Hi All, Some power results from day 1 of the Cederberg MTB. This was my first mountainbike event with a power meter and I used it extensively to pace myself over the 3 days. My aim was not to blow up and to finish the event feeling like I could go for another couple of days. I set my target power for 275w (about 80% of my 20min threshold) and pretty much managed to hold it there on climbs and most flats. Descents pull down the normalised power readings. I weigh 77kg. It was an awesome ride- highly recommended. Day 1 was brutal with over 4 hours in the saddle for me, terrain was very sandy and rocky and temperatures were over 35c. The speed sensor wasnt working so distance shows 0 for the day. If I recall I finished the stage in 26th place, but the leaders were a good 30 mins up on me! 1st hour: Duration: 1:00:00 (1:04:36) Work: 837 kJ TSS: 61.7 (intensity factor 0.786) Norm Power: 267 VI: 1.15 Distance: 0 m Elevation Gain: 525 m Elevation Loss: 405 m Min Max Avg Power: 0 687 233 watts Heart rate: 0 175 157 bpm Cadence: 30 121 79 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 388 639 499 m Crank Torque: 0 81.4 28.3 N-m 2nd hour: Duration: 1:00:17 Work: 896 kJ TSS: 55.7 (intensity factor 0.745) Norm Power: 253 VI: 1.02 Distance: 0 m Elevation Gain: 622 m Elevation Loss: 61 m Min Max Avg Power: 0 760 248 watts Heart rate: 139 176 168 bpm Cadence: 51 118 76 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 545 1106 861 m Crank Torque: 0 102.2 31.7 N-m 3rd hour: Duration: 1:00:02 (1:07:36) Work: 786 kJ TSS: 46.1 (intensity factor 0.679) Norm Power: 231 VI: 1.06 Distance: 0 m Elevation Gain: 495 m Elevation Loss: 366 m Min Max Avg Power: 0 702 218 watts Heart rate: 138 173 163 bpm Cadence: 30 120 75 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 1097 1264 1194 m Crank Torque: 0 93.9 28.4 N-m 4th hour: Duration: 59:21 (1:15:34) Work: 623 kJ TSS: 34.4 (intensity factor 0.59) Norm Power: 201 VI: 1.15 Distance: 0 m Elevation Gain: 213 m Elevation Loss: 728 m Min Max Avg Power: 0 732 175 watts Heart rate: 0 171 156 bpm Cadence: 28 119 76 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 712 1262 1088 m Crank Torque: 0 116.6 22.8 N-m Entire workout (218 watts): Duration: 4:00:23 (5:27:19) Work: 3145 kJ TSS: 203.2 (intensity factor 0.712) Norm Power: 242 VI: 1.11 Distance: 0 m Elevation Gain: 1860 m Elevation Loss: 2282 m Min Max Avg Power: 0 760 218 watts Heart rate: 0 176 161 bpm Cadence: 28 121 76 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 388 1264 908 m Crank Torque: 0 116.6 27.8 N-m Peak 5s (590 watts): Duration: 0:05 Work: 3 kJ TSS: n/a Norm Power: n/a VI: n/a Distance: 0 m Elevation Gain: 0 m Elevation Loss: 0 m Min Max Avg Power: 516 687 590 watts Heart rate: 102 113 108 bpm Cadence: 81 97 92 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 426 426 426 m Crank Torque: 53.4 80.9 61.7 N-m Peak 5min (301 watts): Duration: 5:00 Work: 90 kJ TSS: 6.6 (intensity factor 0.892) Norm Power: 303 VI: 1.01 Distance: 0 m Elevation Gain: 73 m Elevation Loss: 0 m Min Max Avg Power: 75 444 301 watts Heart rate: 159 172 168 bpm Cadence: 68 97 79 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 413 486 450 m Crank Torque: 9.5 52.3 36.6 N-m Peak 10min (289 watts): Duration: 10:00 (10:19) Work: 173 kJ TSS: 12.2 (intensity factor 0.856) Norm Power: 291 VI: 1.01 Distance: 0 m Elevation Gain: 136 m Elevation Loss: 5 m Min Max Avg Power: 0 516 289 watts Heart rate: 147 172 168 bpm Cadence: 43 111 79 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 412 543 472 m Crank Torque: 0 73.1 35.2 N-m Peak 20min (279 watts): Duration: 20:00 Work: 335 kJ TSS: 22.8 (intensity factor 0.827) Norm Power: 281 VI: 1.01 Distance: 0 m Elevation Gain: 263 m Elevation Loss: 5 m Min Max Avg Power: 0 516 279 watts Heart rate: 147 175 170 bpm Cadence: 53 111 79 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 412 670 539 m Crank Torque: 0 73.1 34.1 N-m Peak 60min (259 watts): Duration: 1:00:00 (1:00:40) Work: 931 kJ TSS: 62.4 (intensity factor 0.79) Norm Power: 269 VI: 1.04 Distance: 0 m Elevation Gain: 645 m Elevation Loss: 190 m Min Max Avg Power: 0 674 259 watts Heart rate: 142 176 169 bpm Cadence: 31 119 78 rpm Speed: 0 0 0.0 kph Pace 0:00 0:00 0:00 min/km Altitude: 410 963 653 m Crank Torque: 0 102.2 32.2 N-m
HendrikS Posted October 30, 2007 Posted October 30, 2007 Very Interesting. What power meter did you use for your MTB setup?
1kTT Posted October 30, 2007 Author Posted October 30, 2007 An Ergomo pro. I had to shave down the bb on my MTB from 73mm to 68mm and then I use the same computer as on my road bike. I am sure that if it coped with Cederberg, it will handle anything fine.
HendrikS Posted October 30, 2007 Posted October 30, 2007 Will have to look into it. Heard alot about the Ergomo Pro and that is probably the product to go for. Using a power meter is definately the best way to go...
bruce Posted October 30, 2007 Posted October 30, 2007 An Ergomo pro.I had to shave down the bb on my MTB from 73mm to 68mm and then I use the same computer as on my road bike. I am sure that if it coped with Cederberg' date=' it will handle anything fine.[/quote'] There is an MTB version of the Ergomo, that is wider than the road version. Which one are you using?
bruce Posted October 30, 2007 Posted October 30, 2007 I see that the VI is quite low, so it is a pretty constant effort - similar to a time-trial. Wide range of cadence/torque though.
JasonW Posted October 31, 2007 Posted October 31, 2007 On day 1 there was very little free wheeling hence the narrow gap between avg power and normalised power. I think MTB races will always tend to give a wide cadence range due to the variabiulity of the terrain and the fact that one can seldom get into a steady rythm.
1kTT Posted October 31, 2007 Author Posted October 31, 2007 I see that the VI is quite low' date=' so it is a pretty constant effort - similar to a time-trial. Wide range of cadence/torque though.[/quote'] I am using the MTB Ergomo- but it only fits a 68mm bb and the Yeti was a 73, hence he surgery. Whats VI ? I have never really looked at it before ? I rode the stage exactly like a time trial- the power chart have very long periods where it looks almost flat at 265w-275w. Cadence/torque variability is, I think the biggest difference between road and mtbing. Generally caused by terrain changes.
bruce Posted October 31, 2007 Posted October 31, 2007 I see that the VI is quite low' date=' so it is a pretty constant effort - similar to a time-trial. Wide range of cadence/torque though.[/quote'] I am using the MTB Ergomo- but it only fits a 68mm bb and the Yeti was a 73, hence he surgery. Whats VI ? I have never really looked at it before ? I rode the stage exactly like a time trial- the power chart have very long periods where it looks almost flat at 265w-275w. Cadence/torque variability is, I think the biggest difference between road and mtbing. Generally caused by terrain changes. VI = Variability Index = Normalised Power/Average Power Normalised power takes into account the fact that the physiological demand of riding at intensities above threshold is far greater than riding below threshold. So, if you have a highly variable ride i.e. regular anaerobic bouts, your normalised power will be much higher than your average power and hence VI will be quite a bit bigger than 1. Normalised power is the equivalent steady state (consistent) power that you would have to produce to achieve the same physiological cost. A timetrial is typically a very evenly paced effort, hence VI would be close to 1. But, in a road TT cadence variation would be very small, and gears would be used to keep the power output and cadence in a narrow range. Looking at your numbers, there is a huge cadence variance. The wide range of gears on an MTB would enable this.
BikeMax Posted October 31, 2007 Posted October 31, 2007 You mention riding at 275w as 80% of 20 min power - this would make 20 min power ~340w. In your stats however it appears that you have got FTP set at 340w ? If 20 min power is 340w then it is unlikely that FTP is also 340w - you might want to have a look at this to make sure your levels are right. (Unless you meant 340 was your FTP and not 20 min power) BTW - The Power Tap disc compatible MTB hub is now getting close to a release date for those that might be looking at power on an MTB.
Marius Posted October 31, 2007 Posted October 31, 2007 Wow, that would be awsome to have a Mtb PowerTap!! But come to think of it, I don't use disc's on my Mtb so I guess the normal road PT would be fine? That said, DanNeal said something about the PT having a problem with shock absorbing and loss of date.BikeMax I think 1kTT wanted to do a Tempo ride / L3 for the race which makes since to me since I'll do the same. But it does look like he lost some power during the last hour so this might have been a High L3 and should rather aid for a mid L3 the first 3hours and then gun it a bit harder during the last hour, this works for me but every one has there own why of using there energy.
JasonW Posted October 31, 2007 Posted October 31, 2007 That's great news about the powertap for disc wheels. Looking at 1kTT's stats, it appears that he was riding in mid L2 to mid L3 for the stage. Adapting the figures to my weight (I did a similar time for the stage), I reckon that I was riding mid to high L3 for the stage (on average) with no significant periods at L4. I felt like I was at my limit for the whole stage and finished with an average HR of 90%. I think this really emphasises how important sweetspot training is for marathon length MTB races.
JasonW Posted October 31, 2007 Posted October 31, 2007 But it does look like he lost some power during the last hour so this might have been a High L3 and should rather aid for a mid L3 the first 3hours and then gun it a bit harder during the last hour' date=' this works for me but every one has there own why of using there energy. [/quote'] The last hour had quite a bit of downhill and technical stuff which would have lowered the power. But I also think a lot of us were cramping real bad then as well! It was about 40 deg at that point!
Marius Posted October 31, 2007 Posted October 31, 2007 Jason, silly me, forgot about the downhills and technical parts were you can't really padel:-P I wanted a PowerMeter for my Mtb for a long time already, I think you really need to pace yourself perfectly if you want to be strong till the end and a Power Meter would really help big time!
BikeMax Posted October 31, 2007 Posted October 31, 2007 That's great news about the powertap for disc wheels. Looking at 1kTT's stats' date=' it appears that he was riding in mid L2 to mid L3 for the stage. Adapting the figures to my weight (I did a similar time for the stage), I reckon that I was riding mid to high L3 for the stage (on average) with no significant periods at L4. I felt like I was at my limit for the whole stage and finished with an average HR of 90%. I think this really emphasises how important sweetspot training is for marathon length MTB races.[/quote'] Hi Jason It would be possible for you to be riding at this intensity for this duration if you were going full gas and not worrying aout the next few days - but if this was how you were riding then I would have expected to see you into the L4 zone on the climbs. If you did a similar time then you might want to look at how economically you rode the stage if it cost you that much more energy ? But yes - SST for most any races is a great way to build aerobic fitness and absolutely essential for this type of race as you say.
BikeMax Posted October 31, 2007 Posted October 31, 2007 Wow' date=' that would be awsome to have a Mtb PowerTap!! But come to think of it, I don't use disc's on my Mtb so I guess the normal road PT would be fine? That said, DanNeal said something about the PT having a problem with shock absorbing and loss of date.BikeMax I think 1kTT wanted to do a Tempo ride / L3 for the race which makes since to me since I'll do the same. But it does look like he lost some power during the last hour so this might have been a High L3 and should rather aid for a mid L3 the first 3hours and then gun it a bit harder during the last hour, this works for me but every one has there own why of using there energy. [/quote'] We have seen pretty good results on the MT bikes we have installed PT hubs to - no issues with vibration or data loss or mositure. The data is very different and very interesting and can certainly demonstrate the diffeent requirements of racing MTB vs Road.
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