3.24.2009

Cycling Cadence

Introduction
Lance Armstrong's incredible success and domination of the Tour de France have inspired many cyclists to imitate his extreme high-cadence style. The world watched Jan Ullrich appear to struggle up the climbs at 80rpm while Lance rode away from him at 110 rpm. Many people wondered, "Why doesn't Ullrich just shift to a smaller gear and spin faster? Hasn't Lance proven to the world that very high cadences are better? Well, not necessarily. Lance rode away from Ullrich because he is a stronger cyclist - not because he discovered a secret that Ullrich doesn't know. Should you mimic Lance's high cadence? Maybe. Maybe not.

Pedaling Economy
When you pedal a bicycle, your muscular system produces power to propel the bicycle and your cardiovascular system delivers oxygen, fuels the muscles and removes waste products such as lactic acid. Selecting your optimal cadence is a matter of keeping these two systems in balance. The optimal balance is different for each person.

Spinning at higher cadences reduces the watts-per-pedal-stroke, a measure of the force required to produce a given wattage. This makes the workload more tolerable for the muscles. Most experts believe that this is because fewer fast twitch muscle fibers must be recruited to create the high torque levels required at a low cadence. Pedaling with too-low cadence increases the reliance on fast twitch fibers, causing premature lactic acid accumulation which makes your legs burn.

Pedaling with high cadence, however, does waste some energy. Imagine setting your bike up on an indoor trainer and cutting off the chain. If you spun at 100rpm, the workload would be zero watts, yet your heart rate would elevate significantly above resting. Just moving your legs fast does use energy. Research has consistently demonstrated that cycling at 40-60rpm generates the lowest oxygen consumption for a given wattage. Pedaling at too-high a cadence overloads the cardiovascular system's ability to deliver oxygen to the muscles. The most obvious symptom of this is ventillatory distress.

High-cadence pedaling works your cardiovascular system more, but reduces the relative intensity of the leg muscles. The key, then, is pedaling with enough cadence to keep your watts-per-pedal-stroke at a level that your muscles can handle, but at a cadence that will not overload your cardiovascular system. The optimal balance is different for every rider.

Lance Armstrong vs. Jan Ullrich
Lance Armstrong has an extraordinary cardiovascular capacity. His heart and lungs can deliver enormous quantities of oxygen to his muscles. Yet, Lance does not possess huge, muscular thighs. His muscles are much more likely to be overloaded by high watts-per-pedal-stroke than his cardiovascular system is to be overloaded by the oxygen demand of the workload. Therefore, high-cadence pedaling, even at a slightly higher energy cost, is most effective for him.
Jan Ullrich, on the other hand, is not gifted with the cardiovascular capacity of Lance, but has much greater muscle mass in the hips and thighs. His legs are able to withstand high watts-per-pedal-stroke, so he correctly minimizes wasted energy to prevent cardiovascular limitation. Both Lance and Jan pedal using the cadence that is most effective for their unique physiology.
Finding Your Optimal Cadence
Each cyclist brings a unique set of genetics and training to the sport. The basic rules are, if your legs hurt more than your lungs, increase cadence. If your lungs hurt more than your legs, use lower cadence.

If you decide that higher cadence pedaling might be more effective for you, now is the time to accustom your body to the different demands. Until you have learned the skills to pedal at a very high cadence for long periods of time, you will be less efficient. Each athlete must experiment to find the cadence that works best for him.

Those most likely to benefit from increasing cadence are those whose cardiovascular capacity exceeds their muscle power: women, small or thin riders, former runners and masters riders. These athletes should work to develop a higher-cadence style, but should still incorporate high-force workouts to increase their ability to create torque.

Summary
Analyze whether force and burning legs or ventillatory distress is most likely to limit you at critical points in a race. If legs limit your performance, higher cadence may improve your results once you have adapted. Decide for yourself what style is likely to work, plan a program that will prepare you before important races and get started.

Sources
Cycling Cadence and Pedaling Economy, Ken Mierke

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