By Mike Redshaw
What the Science tells us…
This is a subject everyone has an opinion on but is it backed up with any evidence? This month I wanted look at what the current evidence suggests and try to distinguish fact from opinion.
So where to begin?
Unless you specifically set out to ride at a set cadence then your body will self optimise cadence in order to minimise the metabolic cost (oxygen uptake). A cadence of 50-60rpm has been a shown to be most economical in terms of a lower oxygen uptake over higher selected cadences
However, this doesn’t reflect other important factors though such as mechanical (muscular factors) and biomechanical factors (relevance of speed of movement for example).
Trained runners (no exposure to cycling) select high cadences (85-95rpm) similar to their running cadence and that of well trained cyclists. This highlights the similarities that exist between running and cycling movement patterns. So athletes naturally pedal at their optimum cadence, often this will reflect your natural running cadence and so essentially our bodies tell us what to do! Note that cycling at 15% above your naturally selected cadence is associated with a decrease in exercise tolerance, meaning you will fatigue quicker. So cycling with a cadence similar to that of your optimal run cadence would therefore seem like a good thing to do. Since a much slower bike cadence than when running may mean your body will struggle to reach your optimal running cadence quickly off the bike.
We know that as power output goes up, so does the energy cost, this coincides with an increase in cadence. Cadence needs to increase with high power outputs in order to use the muscle fibres that can produce more power, namely type II muscle fibres. In order to contract type II fibres need to be moved quickly. Interestingly at 90-100rpm the resultant pedal forces applied through the cranks is reduced, suggesting the existence of a “mechanical optimum cadence” within a range of 90-100rpm.
Work looking at rating or perceived exertion (RPE) and cadence found a lower RPE at 80rpm than those reported at 40 & 60rpm despite a higher oxygen uptake and HR values at 80rpm. So there is less perceived effort at higher cadences and given the importance of mindset with longer distance racing self selecting cadences to reduce / maintain RPE makes sense.
There is some work out there looking at the blood flow responses with changing cadences. Some results demonstrate the “skeletal muscle pump” is progressively more effective at high cadences (90-110rpm). Additionally the observed greater blood supply into the tissues may explain why there is a greater energy cost associated with higher cadences. I would point out though that the jury is still out on this point.
Specific research on triathletes demonstrates that cadence reduces along with exercise duration up to 2 hours, suggesting a response to reduce oxygen demand and conserve energy. Lower cadences utilise more type I fibres and these fellas can work for much longer than type II fibres which require greater energy to keep them working. Importantly the same is not true in well trained cyclists and the differences in cycling training may well explain the extensive and more variable muscle co-activation seen in triathletes (cycling 150-250km per week) when compared to trained cyclists (>400km per week).
Trained cyclists and triathletes appear to select cadences of 80-90rom. Despite the increased oxygen demand at higher cadences there are improvements in cycling performance whatever the competitive level.
Cadence is primarily a voluntary and innate rhythm that will reflect your fitness level, the exercise duration and the power output being aimed for. Note that the 1-hour world best performances on the bike are all at cadences of greater than 100rpm. Professional cyclists at 100rpm have lower oxygen uptake and variable muscle activation. The key here though is these guys are professional cyclists and they have different physiological responses compared to age group athletes!
1) Lower cadences based on a theoretical model = less energy cost (oxygen uptake).
2) Cycling with a cadence similar to that of your optimal run cadence would be a good thing to do. Since a much slower bike cadence than when running may mean your body will struggle to reach your optimal run cadence quickly off the bike.
3) Pedalling at a rate that feels natural and sustainable while not too far away from you running cadence is sound advice.
4) 90-100 RPM allows for greater power outputs and appears mechanically more efficient.
5) There is less perceived effort at higher cadences and given the importance of mindset with longer distance racing self selecting cadences to reduce / maintain RPE makes sense.
6) 90-110RPM possibly improves blood flow via the skeletal muscle pump.
7) Triathletes who cycle 150-250km per week will find their cadence naturally reduces as exercise duration increases over a 2 hour period. This is a reflection of bike fitness and therefore the body’s response to conserve energy!