30 December 2014

Effect of pedaling rate

I just came across a recent study that addresses a topic of particular interest to me.

Effects of 2 weeks of low‑intensity cycle training with different pedaling rates on the work rate at lactate threshold, Eur J Appl Physiol, http://link.springer.com/article/10.1007/s00421-014-3081-9

This study suggests that training time spent doing low-cadence strength-type workouts is time well spent. In a nutshell, they found that low-cadence workouts at LT power had a greater impact on improvement of work at LT than higher cadence work at the same workload.

Conclusion:  "Pedaling rate and the corresponding pedal force and peripheral oxygenation during cycling exercise influence the effect of training at LT on WorkLT. Two weeks of training at a low-frequency pedaling rate (35 rpm), but not at a high-frequency (75 rpm), improved WorkLT."

Unfortunately, the study used untrained individuals and tested cadences that could all be considered low. Also, a longer study period (only 2 weeks?) would have been much better. Arguably, the improvements measured might be attributable entirely to enhanced neuromuscular function that was stimulated more effectively at the higher pedal forces.

Nonetheless, the discussion of how cadence impacts VO2, blood pressure, heart rate, blood lactate, and oxy-hemoglobin/myoglobin concentration at the vastus lateralis is interesting and seems to make sense.

Obviously, this training technique can be taken too far and there is probably some increased risk of injury. However, two factors suggest that the risk of injury is not unreasonable:

  1. generally, on-the-bike low-cadence work results in lower pedal force, and therefore joint stress, than strength exercises in the gym
  2. generally, the workouts incorporating low-cadence work, do not result in greater pedal forces than you'll experience during maximal efforts at more typical cadences (sprints, intervals, race efforts)
I would suggest that increased injury risk comes from "overdoing" these workouts in some way.

Of course, there are some studies out there that conclude the opposite or at least find less benefit attributable to this technique.

One such study, Low cadence interval training at moderate intensity does not improve cycling performance in highly trained veteran cyclists (2014), concluded the opposite. I have a hard time buying the conclusion of this study though. Partially because I have some bias or belief that it works, but also because there is no logical reason why it wouldn't at least work just as well as higher cadence efforts at the same workload. Or in other words, how could applying the same central load (aerobic workload) and greater peripheral load (required muscular force), result in diminished improvement? It seems like the authors found that 1+0=2 and 1+1=1. There are some issues with the methodology employed that could have contributed to the result. However, the result still should be considered in evaluating all the evidence.

In any case, these two studies illustrate the difficulties associated with looking at studies of training techniques done in the laboratory for the purpose of publishing an article and trying to translate them into real world training methodologies. On the one hand, the real world is much more complicated. But, at the same time, we are able to apply techniques over a more realistic time period and to our exact set of variables.

Bottom line? In my opinion, formed from personal and coaching experience, and finding support in the scientific literature, this type of work will benefit your riding if done "properly".

Happy Holidays!

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