I’ve been taking a bit of a deep dive into this out of curiosity and it’s pretty tricky. Most sources identify a difference between heart rates in different modalities (either AnT or AeT) but some sources with a specific emphasis on triathletes identify a much smaller variation between cycling and running LTs. The impression I’m getting is the muscle recruitment on a bike is much lower for runners cross training then for cyclists, so a well trained cyclist should have a similar if not nearly identical AeT/AnT.
Heart-rate recommendations: transfer between running and cycling exercise?
This study identifies a difference in the abstract, but without a subscription to the journal or database, I can’t dig in and see if they are testing runners, cyclists, triathletes, etc. or if they are controlling for specific training at all.
Physiological differences between cycling and running: lessons from triathletes.
Here they specifically test triathletes and runners, and found that there is generally no difference in VO2 max between running and cycling in triathletes while runners on the cycling ergometer produce a lower VO2max.
Effects of Cycling vs. Running Training on Endurance Performance in Preparation for Inline Speed Skating
Here they use inline speed skaters in off season to either run or cycle at 52% of their VO2max and found no significant difference between groups in regards to positive improvement in their primary sport. An increase in time trial time was attributed to loss of technique.
The above linked studies primary focus on much shorter duration sports compared to mountain based sports requiring a much longer time underway, so can’t be used in regards to actual training zones and emphasis. However, the conclusions I’m drawing, as much as it is reasonable to do so from just a handful of studies, is for myself, it’s appropriate to keep roughly the same heart rate zones running versus cycling due to the prior training adaptation from collegiate cycling club level racing and training. This prior cycling experience has increased muscle recruitment etc. I understand that running is the far better option for those training for the mountains, but I’m in a similar boat as Scott in that I both enjoy riding my bike, and am finding it a good tool to use while I recover from a tendon sprain in my ankle.
I hope this helps people looking to do some of their own research and if my conclusions are completely off base, please let me know and I will take this post down so as not to confuse others!
