We've seen a prevailing thought about optimal cycling cadence in time trials from a rouleur rolling big gears to spinning high cadences. But should we all aim to adopt the same high rpm TT style? What does science say about cadence, efficiency, and performance?
Optimal cadence may mean a lot of things to a lot of people depending on the context. Certainly there are multiple reasons underlying cadence selection, ranging from the requirements of the event or situation, maximizing power production and/or efficiency, minimizing fatigue, or even comfort. They're all valid reasons, and there's certainly no optimal cadence for all conditions in all cycling events. For example, the acceleration required by track sprinters lead to super-high rpms, whereas a "comfortable" cadence for long endurance rides seem to lead to a self-selected cadence of 90 to 105 rpm on the flats for most cyclists.
In time trials, the prevailing wisdom has always been to roll bigger gears at lower cadences of 80 to 90 rpm until guys like Indurain and Lance Armstrong came along. And hands up who amongst us has not tried to replicate his high cadence time trial (110+) and climbing (90+) style? That's what I thought, and we're not alone. Most of the pros have also attempted to replicate this high rpm style, with varying degrees of success. The question remains—is there scientific basis for all of us to aim for shifting TT cadence upwards?
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Bringing the Road into the Lab
Science and lessons learned from the pros go hand in hand, so it's no surprise that there's been a renewed interest in optimal time trial cadence in the past six years. The prevailing wisdom from older scientific studies was that the optimal cadence, in terms of efficiency (mechanical power output as a percentage of total energy turnover) was shaped like an inverted U, with the peak cadence at approximately 50 to 60 rpm, FAR lower than the typical cadences employed by most cyclists.
The latest papers come from the Norwegian group of Foss and Hallen (1, 2), and they shed a few interesting ideas into the mix. Specifically, they postulate that the reasons for the findings from the older studies was that their tests were: 1) short (< 10 min), 2) at relatively low power outputs (~125 W), and were constant load tests (i.e., ride at the same intensity throughout) as opposed to being a true time trial where performance (i.e., highest power output achievable) was the goal.
Foss and Hallen's 2004 paper attempted to address some of these limitations by having elite cyclists perform an incremental test to exhaustion (4 to 7 min) with cadences of 60, 80, 100, and 120 rpm, and found that performance was highest at 80 rpm compared to the other cadences. This elevates optimal cadence closer to the typical one employed by cyclists, and brings about their interesting idea that the optimal cadence increases with increasing power outputs.