Cadence matters

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Technique: Cadence matters
By Joe Beer | Thursday, May 15, 2008 12.00am

Cycling is a simple sport really. To break it down into its simplest controllable factors you can vary your effort (heart rate), gearing (front and rear combination) and pedal cadence (revolutions per minute).

There are the obvious additional controllable factors of whether you ride on- or off-road and the hilliness of the terrain you choose to cover, but the principle still applies - speed is a function of your effort, your choice of gear and how fast or slow you decide to spin. For example, you can get 30mph with minimal effort in 53x17 downhill, but you can be way up in Zone 3 (86% to 100% HR max), crawling at 9mph grinding your lowest gear if you’re going back up. But what is the best cadence in a given situation?

There has been much research on cadence; McNaughton and Thomas [1] looked at recreational cyclists at varying levels of revolutions per minute (rpm). They found that they were able to ride longer when using lower cadences (~50rpm), versus the classic advice given to beginners of 95rpm, or the even higher 110rpm pro level used on the track, in the pro Peloton and during hour records.

No substitute for training
However, elites are known to pedal faster than beginners, and with more oomph on the down stroke of their pedal action [2]. The exact reason why pros get more force down through the pedals is not clear. But (unsurprisingly) it seems to be due to their muscles, which contain higher blood capillary density and the type of muscle fibres that can only really be built up through years of endurance training – not to mention hill climbing, combined with fast riding in groups that allows high speeds and low effort. This produces high pedalling power and the ability to spin fast.

Interestingly, a Japanese group [3] studying ‘college-aged cyclists’ found that the cadence with the lowest oxygen cost (VO2) was not the same as that producing the lowest muscular fatigue. Measuring the electrical activity of cycling specific muscles, called an electromyogram (EMG), they found 80-90 rpm had significantly lower EMG activity than any other cadence (70rpm, 100rpm) [3].

However, the lowest amount of oxygen was used when pedalling at 60-70rpm, significantly less than 80-100rpm [3]. So, muscles have better neural efficiency when spinning, but this increases oxygen cost. To what extent these can be further trained is not clear, but the fact that professionals can ride at high cadences for hours and that club-level riders tend to ride in ever lower cadences as they tire, suggests cadence is a vital parameter for training.

Round and round…
The above EMG findings may be the result of the college cyclists being less experienced, so they may not depict what occurs with older or fitter riders. It’s also unclear what differences there may be with multi-discipline riders. One study on non-cyclists showed that using the Rotor crank system improved efficiency by 3% [4]. Something Lance Armstrong failed to achieve in ten years of training [5]. Data from an earlier study by Marsh and Martin [6] found that experienced cyclists (250 miles per week) cycling at 200Watts preferred around 85rpm, but this was not too different from inexperienced riders.

However, lowest oxygen cost at around 60rpm, for both experienced and inexperienced cyclists, supports the idea that ‘grinding’ reduces oxygen cost [6]. It may be that 200Watts was too little to stress the experienced riders and more competitive effort (300-350Watts) may have increased preferred cadence. It seems that we all make a complicated assessment of the sensory data coming back from our legs, lungs and head. Grinding lower cadences may be a lower oxygen cost, but the neural system gets tired sooner.

Higher cadence equals better blood flow
The legs act as a more effective blood pumping system when the cadence is higher – if you hit a faster cadence the heart output increases [7]. For the same power output (200Watts as used by Gotshal, 1996) higher cadences make for better muscle blood flow, and in-line with reduced muscle strain data, it makes for better endurance. At 200 Watts (around 20mph) if you spin 100rpm your strain works out at just two Watts per rev, whereas at 60rpm your strain is over three Watts per rev.

Any rider who has ever ridden with power and cadence data to view, using SRM, Polar, PowerTap, Ergomo, Tacx or Cateye, can feel the difference that changes in cadence produce in leg tension, if Wattage stays constant. And here’s the crux: If you use this variety of gearing, power and perceived effort, you can vary training to develop your ability – in other words: Get fitter, faster and better. Now who doesn’t want that!

SULTAN OF SPIN…

Ideas for working on cadence

1. NOVICE RIDERS At least get a cadence sensor on your bike and watch how you actually ride: Are you spinning? Chugging? Or oblivious? Then, once

you’ve made the mental link between your legs and the cadence, start the drills below. It takes time to sense your cadence so only start the drills when you can accurately guess your cadence.

2. FITNESS DRILLS Gain fitness and efficiency by using a cadence sensor with dedicated sessions of:

SPINNING Once warmed up hold a minute each at 90, 100, 110rpm, then spend two minutes at your preferred cadence, before repeating the 90, 100, 110 spin drills for two minutes each. Do this once more for three minutes at a time before descending through two and one minute spin intervals. Aim to hold periods of 20 minutes.

POWER UP Warm up for at least 20 minutes then find an incline around five percent (1:20). Ride three minutes uphill at your preferred cadence around 85% HRmax, then spin back down before riding another three minute incline in a gear one cog bigger on the rear cassette. This will mean cadence drops, but your power per revolution will be higher. Repeat the drill until you get either big lactate burn or your breathing gets out of control. Aim long term to adapt to low cadence work and being able to tolerate using bigger gears up your power incline.

3. ADVANCED Use your cadence sensor and HR monitor to see how you race and where you can improve. Do drills as above (cadence and power inclines). Also consider rollers, fixed wheel road and/or track work and some off -season mountain biking or cyclo-cross fun.

References:

[1] McNaughton, L. & Thomas, D. (1996) Effects of differing pedalling speeds on the power-duration relationship of high intensity cycle ergometry. Int. J. Sports Med. 17(4): 287-292.

[2] Coyle, E.F. et al (1991) Physiological and biomechanical factors associated with elite endurance cycling performance. Med. Sci. Sports Exerc. 23(1): 93-107

[3] Takaishi, T. et al (1996) Optimal pedalling rate estimated from neuromuscular fatigue for cyclists. Med. Sci. Sports Exerc. 28(12): 1492-1497.

[4] Santalla, A. et al (2002) A new pedalling design: the Rotor-effects on cycling performance. Med. Sci. Sports Exerc. 34(11): 1854-1858.

[5] Coyle, F. (2005) Improved muscular efficiency displayed as Tour de France champion matures. J. Appl. Physiol. 98(6): 2191-2196.

[6] Marsh, A.P. & Martin, P.E. (1993) The association between cycling experience and preferred and most economical cadences. Med. Sci. Sports Exerc. 25(11): 1269-1274.

[7] Gotshal, R.W. et al (1996) Cycling cadence alters exercise hemodynamics. Int. J.Sports Med. 17(1): 17-21.