Power Meters in Bikepacking

[GregMay]

<science hat>

Probably not aware for many that my background is in performance physiology. PhD concerned with ultra-endurance physiology, working with RAAM and other such riders. Who knows why I am so slow, but I digress.

I've noticed a trend over the past few years - first in 24hour racing, now in bikepack racing - for riders to race with power-meters. A side shot of JP this year shows him on a Quarg, few other bikes I've seen running Stages, at least one looked like it was on a Power2Max - but it could have been Quarg (too much mud to make out!).

For those interested I had a power meter during the training for HTR in 2013, used one for a few ITTs over the years, and had one training for the TDR last year. I think I've had one in some form since 2008! I've used one heavily while preparing, and racing for WEMBO in 2015 and other 24hour races - my 3rd place at WEMBO wouldn't have happened if I wasn't using one as it let me pace smarter. But I digress.

What I'm really interested in is to know how they are being used by the fast folk for racing?

Main use as I see it - CHO/Fat utilisation. Something I've used with UE athletes for years across RAAM/RAI/24-Solo/Ironman racers. You go to a lab, connected to a full breath by breath metabolic system, and over a few hours you spend time at different power outputs for chunks of time (10-15mins). You can calculate from the expired C02 and inspired O2 volume how many grams of CHO and Fat you are using at a given power output. It's not a fun, or interesting test. Generally get the UE athletes to turn up after they've already being riding for 3/4 hours so that we know they are primed so to speak.

Secondary use is always going to be pacing - but with the length of the day and multi day rides I'd personally find it really distracting to be focusing on it for more than the major climbs, or into a headwind.

Batteries would need to be user replaceable - so SRM is out - and easy to find. Stages, Quarg, P2M are all CR2020/2035 I think? Easy to pick up en route during the TDR, but not so much on CTR/AZT/HTR/Turino-Nice for example.

I wonder, as I am sat in work, trying to figure out how to externally power a wireless, weather sealed EMG sensor to allow us to look at muscle activation and decay patterns in UE cycling and running.

</science hat>

Is it worth the extra weight or faff?

[touch]

Once you get used to riding with a power meter it becomes quite easy to go out for a few hours and stick to whatever power zone based purely on RPE and not looking much at the power meter.
It gets harder and harder to estimate your power from RPE as you fatigue on longer rides and multi-day events. I'd guess they wouldn't need to ride around looking at their powermeter numbers all day but just 'recalibrate' between RPE and actual power every now and then.

Batteries shouldn't be an issue. I've had a powertap hub and garmin vector pedals and both run for several months before needing replace. Sure, I wasn't riding 20 hours a day every day but I think a fresh set of batteries at the start of something like the TD would last the entire race.

[Bearbonesnorm]

I feel like we're entering a new and different world. As a 'non-racer' and a man of simple things, it's one I don't comprehend

[padonbike]

I've never seen anyone at the fast end of the HT (or any end of the HT, come to think of it!) using a power meter.

I'm basically a roadie who rides mountain bikes and I'd never touch them. Nor pulsemeters.
If I ride in Weardale and can climb for 4 hours at 500m cumulative altitude per hour, then my power is right. Obviously I avoid doing this as it's unpleasant, but the theory holds up.

I can see why they are relevant in the pro road game, but I think most people equate buying/using a power meter with somehow getting more power.
Unlikely - your physical gifts are what they are.

There are some fast people in the UK doing bikepacking races right now and the trend is getting faster but I don't know anyone using a power meter, let alone racing with one and believe me, I keep my eye on who is fast.

As Pantani correctly said, "when you are at the limits of fatigue, only your natural gifts can help you."

[GregMay]

I feel like we're entering a new and different world. As a 'non-racer' and a man of simple things, it's one I don't comprehend

It's ok Stu, one does not have to comprehend everything.

[GregMay]

I've never seen anyone at the fast end of the HT (or any end of the HT, come to think of it!) using a power meter.

I rode one in 2013. But that is beside the point.

It's not about what you've seen, more what you think.

As Pantani correctly said, "when you are at the limits of fatigue, only your natural gifts can help you."

And amphetamines. Bad example to use.

[whitestone]

I'd considered getting one for the road bike but more for the geekiness of it really Quite what I'd do with the data it produces I've no idea. More useful on the turbo or track IMO. Once you get out into the real world there are so many variables outside your control, particularly in mountain biking, that any figures are all but meaningless. Read the various reports on this year's HT: on the section between Fort Augustus and Fort William, which is essentially flat, some had a strong enough headwind that there were white horses on the canal while others, like myself, had no wind at all. Obviously the rider that can push out 5 Watts/Kg is going to be faster than the rider who can push out 3 W/Kg in a given circumstance but if the 5W rider has the headwind and the 3W rider doesn't then the stronger ride might be using a lot more energy to go at the same pace.

I think times in ITTs are getting faster more because people know how to ride them better, whether that's knowing themselves better or knowing the route (including supply points, etc.) better. I've a pace/RPE/power output (call it what you will) that I know I can maintain for the duration, it's what I do outside that that has the most variable effect on my overall time. There's more knowledge out there and that will only increase so rather than basing a pacing strategy on one or two riders who may have had a bad patch or hit bad conditions at some point you'll be able to average out ten or more. Might take the "fun" out of it though. As someone who's definitely mid-pack, I don't see many (any) power meters around either, then again I wasn't looking out for them.

Pantani and "natural gifts" hmm

[Richard G]

I train with power, but I can't see it being of much use on the more technical terrain that I see on ITTs.

There's also probably a limit to how serious I'm willing to get on something that I'm supposedly doing for "fun".

[GregMay]

Whitestone - Good input, guess I'd not thought that those using them on ITTs do generally have history with the routes they are trying to go faster on.

Agree for track/TT use - utterly indispensable IMHO. Ironman too.

Richard G - Yeah, at what point does it become not fun? More training than riding? I end up staring at a small screen anyway most of the time on faster ITT runs so I don't end up going off route and then have to self relegate. Not actually sure I've looked at power data since I've come back from the TD. Will probably use it again training for CTR/WEMBO next year.

[ZeroDarkBivi]

I am not fast, but fascinated by the application of new technology, so used a PM on road bikes since 2006, when I was doing triathlon. I have found it very useful for pacing in longer events and in structured training, but one only has to look at people like Chrissie Wellington to see that some top athletes still prefer to race on feel.

I wouldn't mind having access to power data to analyse after an ITT, but probably wouldn't use it much during the event, and riding to a number when off road would be quite difficult, and perhaps distract me from my primary concerns of staying on the bike, and staying on the route. So not enough utility for me to justify the investment. Reliability would be another concern, rather than batteries; 250 hours should get me through most things, but I'm not convinced the device would hold its accuracy when exposed to the harsh trail environment.

However, if you have a spare PM available in 165mm cranks...

[GregMay]

but I'm not convinced the device would hold its accuracy when exposed to the harsh trail environment.

My stages has been OK for two years now - winter SS most of the time and Calderdale mud. The SRM before that....not so good.

[Richard G]

Richard G - Yeah, at what point does it become not fun? More training than riding? I end up staring at a small screen anyway most of the time on faster ITT runs so I don't end up going off route and then have to self relegate. Not actually sure I've looked at power data since I've come back from the TD. Will probably use it again training for CTR/WEMBO next year.

It's far more staring at a screen. In my experience you only have to check a screen when you're at a place where the trail could theoretically branch (or where there's any evidence of multiple paths).

But more than that, there's very little enjoyment to be found in sitting at a specific power output for best efficiency. I train hard so I can enjoy these rides. I'm not a pro athlete, and there are no prizes to be won at the events I do. If I finish first, super, if I have to negatively impact my enjoyment of the ride massively to do so... not so much.

That said, we're a strange bunch, I'm sure there must be some out there who enjoy looking at power numbers rather than scenery.

[padonbike]

And amphetamines. Bad example to use.

The point is that whatever drugs he took, he rode on instinct and rode a lot faster than a lot of people who did a lot more self-analysis. And used the same drugs in the races.
Similarly, there's a larger number of people out there who have ridden a faster HT550 without power meters, than those who may have ridden it with one.

Plus you're totally forgetting extra electronic complexity in self-supported racing: surely something to simplify, not make more complex!
There are already the essential electronics of lighting and navigation, where problems can occur, so why would anyone add complexity with a power meter, which is another electronic thing.

Agree for track/TT use - utterly indispensable IMHO. Ironman too.

Triathletes use what their coaches tell them to use.
You ride your bike for 5 or 6 hours sticking strictly to power numbers, then get off and run for 3 or 4 hours having to rely on your natural pacing as there is no such thing as a running power meter.
How can you possibly predict a certain power number for e.g. 6 hours riding that's going to permit your legs to run for 4 hours? You can't. There is no scientific relationship between power you expend on a bike and "amount of freshness in your legs to run a marathon afterwards."

[whitestone]

The Garmin (Edge 510) I use for road riding has the concept of HR zones, you can set alarms so that it'll beep at you when you are naughty and stray outside the prescribed zone. No real need to look at the screen. I'd imagine that if you pair a power meter to it then you could set similar limits on those values. Not sure how it would work with freewheeling down a hill : "pedal faster you lazy f***er!" It's pretty soul destroying riding though, I managed a couple of months doing it for a couple of rides per week, it's riding for training not for the joy of riding.

I've seen power analysis of a rider in one of the CX world championship races which was interesting and humbling at the same time but I Imagine the rider herself wasn't bothered about power figures at the time more how she could cover a move by her rivals.

[GregMay]

Pantani.... seriously? Not a role model.

How can you possibly predict a certain power number for e.g. 6 hours riding that's going to permit your legs to run for 4 hours? You can't. There is no scientific relationship between power you expend on a bike and "amount of freshness in your legs to run a marathon afterwards."

OK, I'll bite, mainly as you're talking nonsense and there is a huge body of evidence showing you're incorrect - go dig about on Pubmed with the search "pacing strategies and triathlon". Here, have two papers to start with:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4172046/
https://www.ncbi.nlm.nih.gov/pubmed/27817192

It's been shown, over and over, that the pacing strategy adopted during the bike leg of a triathlon effects an athletes energy stores. The same as the swim effects the bike and the run. From sprint distance to Ironman.

1) It's not about predicting. If you'd used the word modelling I'd have given you slight leeway. It's about calculating the energy expenditure at a given power output including the change over time and reduction in available carbohydrate and fat stores in a lab environment and applying them in the field in order to estimate a potential finish time.

2) Yes, you can measure the effect of the power expended during the cycle leg on running time in triathlon. It's pretty easy. This can then be fed into models to estimate a running finish time based on known tests with an athlete.

3) You're correct there are currently no commercially available consumer level power meters for running. However the mechanics and energetics of human walking and running have been documented and reported on for years. We have a very, very high level of understanding of what is going on from an energetics system and the effect of prior exertion.

4) There is no such thing as measure of freshness, or fatigue, no matter what Strava may tell you. Give me an SI unit for either of them. They are words that people use to describe feelings, nothing to do with a scientific variable. Pick one argument or the other. We can model the long term effect of training fatigue, no more, no less. We cannot ever, get a point measure for "freshness" as a concept. RPE is about as close as well get.

[GregMay]

you can set alarms so that it'll beep at you when you are naughty and stray outside the prescribed zone. No real need to look at the screen. I'd imagine that if you pair a power meter to it then you could set similar limits on those values. Not sure how it would work with freewheeling down a hill : "pedal faster you lazy f***er!" It's pretty soul destroying riding though, I managed a couple of months doing it for a couple of rides per week, it's riding for training not for the joy of riding.

Yup you can. We used it with RAAM athletes a few years ago - set an upper boundary above which they we're in a no-no zone and had to back off. I tried it one evening when on the way home from the lab and found it made my rides a bit more boring, so turned it off.

I've seen power analysis of a rider in one of the CX world championship races which was interesting and humbling at the same time but I Imagine the rider herself wasn't bothered about power figures at the time more how she could cover a move by her rivals.

Reactionary sport isn't it? Like a crit, numbers are more used afterwards to fill in data for quadrant analysis and looking at performance change lap by lap. Or at least that's what my old coach did! But you're right, no way they are looking at the numbers during a race. Similar to track sprinters, or most road racers. Chris "stem starer" Froome aside.

[Cheeky Monkey]

I say this bearing in mind it takes all sorts and one man's pleasure is another's poison, however, I couldn't give a FF

Nice ride, nice spot, comfy pit and a bit of bait, whisky/booze and a banter or more often just getting lost in my own head in a peaceful spot. Powermeters don't come into it.

TBH that means this thread isn't really for me Tho' Greg, with regards your response to Pad', please chill out a bit

[GregMay]

Happy to chill, maybe I need to spend less time in the lab with the other nerds.

Onwards.

[AlexGold]

Running power meter: https://www.dcrainmaker.com/2016/08/str ... er-v2.html

[ZeroDarkBivi]

Was a bit surprised to read an article by Chris Boardman (I forget where), stating that whilst he used power for many years for both training and assessing aerodynamic positions, he never looked at it for pacing during a Time Trial.

I remember asking a racer at the Brek Epic why they had a power meter on their MTB, and got a very honest answer; "because I am a geek!"

[Scott L]

Bit of Power based patter from James Hayden of riding bikes fast in the Trancontinental...

http://jamesmarkhayden.uk/transcontinen ... ntinental/

I like the idea of using it to 'hold back' so to speak early on in the events but cannot really imagine wanting it for mountain biking other than that. My girlfriend uses one for her riding and training and finds it useful for hill efforts and the like.

Each to their own.

[slarge]

I like the thought of power meter training, but the reality I suspect is very different. To see how much you put out during a given hill or fast bit would be interesting, but to train to? Not sure about that.

A friend of mine started a proper structured training plan with heart rate, power, fat measurement etc some years ago, and went from a rider about the same speed as me to one a bit faster. So they clearly can work, just not sure if they are as useful on a mtb as they might be on a road bike.

ITT rides with one? Only to hold you back in the early stages I suspect, but wouldn't heart rate or sweat factor do that?

[johnnystorm]

I'd like to give one a whirl. Using power on the Turbo has helped a lot and pushing on without blowing up would be nice.

[Dovebiker]

My mates an Ironman geek - regular Hawaii qualifier and has all the toys - but no amount of digital mcguffery stops his legs from falling-off on the run

I could see they're of benefit whilst training to optimise your training load, but less so in an event where it's also about hydration, navigating, feeding, sleeping....all important factors

[Bearbonesnorm]

It's ok Stu, one does not have to comprehend everything.

That's a relief ... whenever I look at this post, I feel like I've joined another forum by accident