Hill climbing and making the most of my gears

[Exit Stage Left]

I tend to climb based on a modification of the following formula.

W = krMs + kaAsv2 + giMs

where W is power, kr is the rolling resistance coefficient, M is the combined mass of cyclist and bicycle, s is the bicycle speed on the road, ka is the air resistance coefficient, A is the combined frontal area of cyclist and bicycle, v is the bicycle speed through the air (i.e. road speed plus head wind speed), g is the gravitational acceleration constant, and i is the road incline (grade; however, this is only an approximation, as the sine of the road angle to the horizontal should technically be used).

I find that in addition to those factors I have to allow for the decreased rate of evaporation of sweat at low air speeds, so I have to account for temperature and humidity, as increasing core temperature will limit output. Sometimes I forget to use the sine of the road angle to the horizontal and I overcook it.

Higher cadences are advised, based on a number of studies.

While the power requirements of cycling uphill can be easily described, there are many factors which affect a cyclist's ability to economically apply that power. Having a high sustainable aerobic power will not translate into superior speed unless it is effectively converted into external motion.

One factor that influences cycling economy is pedal cadence. A number of studies have demonstrated that cadences of 80 to 90 rpm allow the most economical use of aerobic metabolism when performing at high power outputs in level cycling. Despite this, competitive cyclists are often observed to climb hills at substantially lower cadences.

The reasons that some cyclists appear to prefer lower cadences during hill climbing are not clear. However, a simple mechanical explanation is evident. The addition of the gravitational component to the forces opposing the cyclist necessitate a marked reduction in road speed. Unless the cyclist has correspondingly lower gear ratios available on his or her bicycle, pedal cadence will fall. Road racers often do not possess sufficiently low gear ratios on their bicycles, unlike competitors in the off-road sport of mountain biking.

Perhaps due to the low cadences during climbs, road racers are often observed to stand while pedaling. This strategy effectively shifts their body weight forward over the pedals, which might allow for greater force production for the low speed, high force revolutions.

While these potential benefits should be examined, a laboratory investigation of climbing demonstrated that a high cadence (80 - 90 rpm) elicited the lowest oxygen consumption (Swain and Wilcox, 1992), just as was previously shown for level cycling. From available scientific evidence, it would appear that the use of lower gear ratios on climbs might enhance performance.

http://www.sportsci.org/jour/9804/dps.html

Obviously not everyone will have my 'devil may care' and 'seat of the pants ' attitude, and may wish to have some rationale behind their climbing.

[Gareth Rees]

Sometimes I forget to use the sine of the road angle to the horizontal and I overcook it.

I am puzzled by this claim: the sine is always less than the tangent, surely?

[zigzag]

during longer rides i tend to ease off when riding on flat(-ish) surface, but go up the hills try give about 90% effort. this way i can imitate interval training which is good for speed, and decrease the time it takes to complete the ride (speed uphill matters more than on a flat for overall time, if that makes sense).

[Exit Stage Left]

Sometimes I forget to use the sine of the road angle to the horizontal and I overcook it.

I am puzzled by this claim: the sine is always less than the tangent, surely?

I end up trying too hard. Sometimes I forget to put the book of log tables in the map holder, and the slide rule requires two hands.

[citoyen]

Perhaps you should use an OS map to calculate gradients and work out the appropriate gear and cadence for each part of your route before the start of your ride, and write them down in an audax routesheet stylee.

Though I can see this doesn't quite fit with your preferred seat-of-the-pants approach, but at least it would mean you could leave the slide rule at home, thus saving some weight.

d.

[Exit Stage Left]

Perhaps you should use an OS map to calculate gradients and work out the appropriate gear and cadence for each part of your route before the start of your ride, and write them down in an audax routesheet stylee.

Though I can see this doesn't quite fit with your preferred seat-of-the-pants approach, but at least it would mean you could leave the slide rule at home, thus saving some weight.

d.

Clearly the component 'v' is of great importance, as it is squared, wind speed and direction is a big factor, so I tend to use a detailed weather forecast to aid cassette choice. I find the Yr.no hour by hour forecast invaluable.
http://www.yr.no/place/United_Kingdom/England/Blackpool/hour_by_hour.html
precipitation and temperature help me judge my maximum effort.

[mattc]

Obviously not everyone will have my 'devil may care' and 'seat of the pants ' attitude, and may wish to have some rationale behind their climbing.

[LEE]

Sometimes, when the going gets really tough I press my STI shifter hard, just in the vain hope there's an extra gear I forgot about. 

There never is.

If it get's really, really, tough I may even glance back and check the chain is really on the biggest sprocket and my STIs haven't malfunctioned.

It always is and no they haven't.

As a technique, for climbing quickly on a long climb (something I try to avoid), I will count 20 sat down and 20 honking..repeat until lungs and legs fail then sit down and spin.

[Exit Stage Left]

Ultimately you need to be strong enough to ride slowly. To be able to turn over a gear at a very low cadence so that your heart rate doesn't go haywire. Riding fixed or just going everywhere in a big gear helps this. When you can do that you can back off when the heart rate goes over the aerobic threshold. HRMs are quite useful for that.
When I used one I would consciously try to recover on the less evil parts of the top of Yad Moss between the 25% ramps. There's inevitably a lag between effort and heart rate, as the blood oxygen level adjusts. I've got lots of blood. so it takes a while.
Another factor is how you use any fast twitch muscle you have. If you know that a section of a climb has a steeper pitch you can use those sprinting muscles to get you over that bit, before settling back to use the slow twitch ones, this is also what you are doing when you 'attack' a hill. That kind of lactate management is what you are seeing on a set piece Tour climb. I've actually got quite a good 'kick' and if I see a suitable slight rise I'll generally put in a full-blown anaerobic burst to alarm people who know I won't exert myself climbing longer slopes and haven't considered that short climbs are completely different.

[mattc]

I might be taking some kind of bait here ...

but I don't believe fast twitch muscles are any better at dealing with lactate. They're just better at twitching fast. Going hard will always have a downside.

[Feline]

I hadn't thought of different sets of muscles having different 'pools' of lactate in them, I'd imagined the reason my heard rate goes haywire is that I've actually got lactate in my blood at that stage and therefore which ever muscle groups I try to use won't go so well. Am I misunderstanding this?

[Exit Stage Left]

Slow Twitch (Type I)
The slow muscles are more efficient at using oxygen to generate more fuel (known as ATP) for continuous, extended muscle contractions over a long time. They fire more slowly than fast twitch fibers and can go for a long time before they fatigue. Therefore, slow twitch fibers are great at helping athletes run marathons and bicycle for hours.


Fast Twitch (Type II)
Because fast twitch fibers use anaerobic metabolism to create fuel, they are much better at generating short bursts of strength or speed than slow muscles. However, they fatigue more quickly. Fast twitch fibers generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly. Having more fast twitch fibers can be an asset to a sprinter since she needs to quickly generate a lot of force.

http://sportsmedicine.about.com/od/anatomyandphysiology/a/MuscleFiberType.htm

I used to put a lot of effort into combining high end aerobic exercise, 10 mile TTs, with some anaerobic sprint training. I needed to be able to sprint off the front of a group to known scenic video locations, then time trial my way back to the group. Audaxers don't generally have much sprint capability. Doing this trick uphill is impossible for me due to my weight, but it is possible to use some of that sprint power if you have a HRM and a thorough knowledge of the hill. The trick is to judge how much lactate a burst will create.