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My watts per kg on hill 5 minute hill climbs seems to be 30 to 40 watts higher than what I can achieve on the flat. This is where I get dropped the most often during group rides and races.

My maximum 5 minute watts/kg on a hill climb is: 4.90 The average gradient of the slope is: 9% Here is the pf/pv graph for this entire ride

But on the flat the maximum I have managed is: 4.37 here is the pf/pv graph for that entire ride

I would like to add I'm not sure how to extract the data for just the vo2max intervals or whether that would be more useful or not.

Do I train each separately to give myself the best chance of improvement in each discipline?

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    Before giving an answer, we'd need more information, especially two things: 1) how are you measuring these maximums; and 2) have you looked at your pedal force/pedal speed, especially with gradient of the slope? Depending on your answers, you may not need to "separate" your goals. – R. Chung Jun 12 '14 at 23:49
  • Excellent. Thanks for the PF/PV plots. This is very helpful. You can use the "find interval" tool to zoom in on the "peak" 5 minute power for each of those rides (then highlight the peak interval and look at PF/PV again), but I suspect that we already have enough info. For neuromuscular reasons many riders have an easier time generating high pedal force at low crank inertial load, such as usually occurs during a steep hill climb (you can see the difference at around 1 m/s (~60 rpm) and 350 N). If you can supplement with those two plots I may be able to give a fuller answer. – R. Chung Jun 13 '14 at 13:11
  • BTW, after you've found that peak 5-minute interval you can switch to the Aerolab (or, um, Chung Analysis) tab to verify that the peak interval occurs on the climb. – R. Chung Jun 13 '14 at 13:56
  • Just out of interest: what software do you use there? – Benedikt Bauer Jun 13 '14 at 14:11
  • @BenediktBauer - it's Golden Cheetah (www.goldencheetah.org). Free and open source, so check it out! – Darren Cope Jun 13 '14 at 15:35
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The short answer to your question is, no, you don't have to separate your "VO2Max power" between flat rides and climbs. However, specificity matters and the pedal force/pedal speed plots show that the demands of flat rides and steep climbs differ, so you may want to keep that, plus your recovery capacity in mind when you train.

The longer answer requires some explanation of VO2max, your power "at VO2Max", the differences between 5-minute efforts and longer efforts, and power application within the context of a race.

VO2Max is the maximal amount of oxygen you can consume. It is usually normalized by body mass so is measured in ml/min/kg. It is not independent of the sport you are doing so VO2Max can differ between cycling, running, rowing, or xc skiing, but the dependence among trained athletes is relatively small, perhaps 5% or so, usually less than 10%. The difference can be greater among athletes who are novices to a particularly sport, but here we are talking only about cycling, and about riding on the flat vs. climbing up steep slopes.

A larger issue is that although we typically say that the oxygen you consume during maximal effort over 5 to 8 minutes is a good predictor of your VO2Max, it is often hard to spot a truly maximal effort from data collected during a race, especially a mass start race. The reason is that during a mass start race, tactics will depend on context, so picking out the "peak 5-minute" effort may often be an interval where you still have a long way to go to the finish line instead of collapsed in the gutter on the side of the road. For hill climbs, especially but not limited to TT hill climbs, once the climb is over you often (though not always) have a respite and can recover a bit on the descent. Therefore, just looking at 5-minute peak power during races typically won't be a good estimator of your true VO2Max. That is, your "VO2Max power" may not differ much between types of races but your 5-minute peak power can be quite a bit different, depending on the race.

That said, a look at the pedal force/pedal speed plots shows that hill climbs can require a different pattern of cadence and force than rides on the flat; and some riders may have an easier (or harder) time generating those patterns on particular types of terrain. Here is a plot for one rider showing his overall cadence/crank torque (very similar to a pedal force/pedal speed plot) during hill intervals. The upper left panel shows his overall pattern, the upper right panel shows that the elevation profile for the ride; as can be seen, he rode out to a nearby hill, did four climbs and descents, and returned home. The climbing portion of the ride is shown in red while the flatter parts are shown in black. The lower two panels show the cadence-torque patterns used for the climb and for the flat. It is evident that they are different.

cadence and torque for hill climbs and flat riding

Below, you can see cadence-torque plots for the same rider in three different types of races: a hilly (but not mountainous) road race, a flat urban loop criterium race, and a rolling time trial.

cadence and torque for hilly RR, flat crit, and rolling TT

Largely speaking, cycling speed on climbs is mostly determined by power-to-weight, while speed on the flats is mostly determined by power-to-aerodynamic drag area. This means that power scales with speed differently on climbs vs. on the flats. Another thing that varies with climbs vs. flats is crank inertial load, and empirical research suggests that some riders are more "sensitive" to changes in crank inertial load than others, and will choose different combinations of pedal force and pedal speed to produce the same power (say, the same 300 watts) on the flat than on climbs. We would need more data to be sure but another contributing explanation to why there is a power difference between your climbing and flat land power is that perhaps you are one of those riders who can produce more power over short durations (like 5 minutes or so) at low cadence and high torque than at high cadence and low torque. This is something that cannot be answered from only two rides but it is something to keep in mind.

So, different types of races put different types of demands on the racer, and different racers can have different preferences for how to "feel most comfortable" in producing that power. If you do different types of races you may want to be sure to include training not only for your FTP or VO2Max "power" but also the pattern of pedal force and pedal speed that characterizes each type of race. As an aside, these different patterns of pedal force and pedal speed during climbing show why simply elevating the front of a bike on a trainer a few degrees does not produce the same training effect as actual climbing on a hill.

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TL;DR

Your output should be consistent regardless of what type of terrain you're riding on, but external factors coupled can skew the results.


I've trained with power for many years, and while my evidence to the following points is purely empirical, maybe it will help you.

In my experience, I've always achieved higher W/kg results on hills than riding on flat ground. I believe this is because:

  • More consistently positive gradient. When riding on flats, typically the ground isn't exactly flat, and will fluctuate between +/- 0.5 percent without the rider noticing. Going down a 0.5 percent might translate to the rider as a false reprieve from the effort at hand, skewing the average. As I'm sure you know, maintaining the same wattage downhill is difficult, though probably because of purely psychological reasons.
  • Fewer external factors such as wind to content with. It should be noted that air resistance (drag) approximately follows a squared relationship with the free-stream velocity. Therefore, a tailwind or gust of wind while climbing 8 mph has less effect on power output than a tailwind while travelling at 25 mph. This will lend itself to more consistent power output.
  • Flat and straight roads tend to have high speed limits, which means cars will be passing you faster. This wash from the cars can skew your results through the same logic as above.

Granted, this evidence is only anecdotal but these are the assumptions I've always used to justify differing performance numbers.

As an aside, I've looked up your W/kg on a cycling chart. 4.9 W/kg puts you at a high Cat 3, low Cat 2 range. Even at 4.37 you're still a solid Cat 3. If you're getting dropped on group rides with these kinds of numbers, I would suspect that your limiting factor isn't your 5 minute power (unless, of course, you're exclusively riding with Cat 1 riders). I would take a guess that your limiting factor isn't your power, but your ability to recover after efforts. Decreasing recovery time allows you to attack more, recover from surges at FTP, and makes your a more resilient rider. That being said, while 5 minute power is a decent gauge of fitness, the real litmus test is the 20 minute from which you can estimate your FTP. I'd be interested to see those numbers.

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  • my ftp is 3.29 watts/kg so that would also be a contributing factor to the getting dropped as well as the 'lower' fatigue resistance. – user95786 Jun 16 '14 at 12:08
  • Precisely. With numbers that are Cat 1/2 range for 5 minutes and Cat 5 range for 20 minutes, you're bound you have underwhelming performance. – Tyler Jandreau Jun 16 '14 at 13:10
  • I'm guessing you're referring to Coggan's Power Profiling Chart. Coggan has always disliked that particular use of his chart and has been de-emphasizing the Power Profile in favor of his (newer) fucntional reserve capacity. – R. Chung Jun 16 '14 at 14:39

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