I’ve been doing more outside workouts and today while doing a longer threshold workout I started thinking if there is a big difference between flats vs climbs. I live 15mins from a long, uninterrupted farming road which I been riding a lot and 55mins from my local ski road so I have options for sweetspot and threshold work.
I read this article and a couple of TR forums where they explain that slightly different muscles are activated.
I’ve always found generating threshold power on flats to be much harder than on climbs but now thanks to trainer road and doing these type of workouts outside it seems much more manageable.
So my questions are - is the training effects the same on flats vs climbs if power is the same? If I do most of this work on flats am I going to suffer on hill climbs because I’m not as use to the change in grade / cadence required?
I asked this exact question to Coach Frank Overton at Fascat Coaching (Phil Gaimon’s coach) and he said (paraphrasing) no. The physiological difference of doing 3x10 at 280W on the flats or trainer is “very close” to 3x10 at 280W climbing.
I also linked that ^^^ Cycling Tips article to a thread a long time ago. I think while physiologically what Frank said might be right It won’t necessarily make me an amazing climber or you dump huge watts on the flats. We can improve climbing or flat riding though and that’s the point.
Just to pose the alternative, there are compelling literature noting differences in biomechanical and metabolic recruitment between flat and uphill cycling. The same power output may have different efficiency and distribution across muscle groups due to differences primarily in cadence, body position, and crank inertia between conditions. I experimented with this recently in the context of trainer vs road cycling. Many of the references are relevant to uphill vs flat road cycling.
Maybe start with this 2015 study and look at the references for more background. It’s an interesting rabbit hole, but nothing conclusive to your original question. More studies are slowly coming out as we can actually experiment with VO2 & other metabolic devices in field conditions!
I would guess that if power output were the same between conditions the overall stimulus will likely be more or less the same for any single session. Although maybe small differences in muscle recruitment strategies between conditions could add up to relevant performance differences over long enough time (eg. a season or a lifetime of training in the hills, vs training on the flats).
IMO you could just say comfort and familiarity on your preferred terrain will contribute more to greater performance and therefore better adaptation, than any actual physiological difference between terrain.