Above comments are good but just in reply to this question:
“Also, is the time savings on the bike by pushing harder more than the time savings of having a slightly better run?”
I believe people incorrectly do the accounting on this–you have to keep in mind that in cycling wind resistance is your biggest energy consumer whereas in running it is more biomechanical efficiency. So, with that in mind you reach a point of diminishing return on the bike. If you are looking at 85% of stand alone effort on one leg and 95% on the other I think you will do better on overall time pushing the run. The extra effort on the bike buys you less time savings because of the relationship between input power and drag. So if you bike 10% harder you may go 3-4% faster. Whereas in running 10% harder is close to 10% faster. While the bike is longer I think generally you would do better to hold back a little and then hammer the back half of the run if things are too easy.
It depends a lot on training load.
The bike is diminishing returns but time is still time. Run also isn’t 1:1. You mechanical efficiency, while it varies individually, will drop as well as heat management. You’ll burn more “overhead”. Plus you realistically can’t run a whole lot faster than threshold pace. So the most you can gain running is probably 1 minute. So if I give up 2 minutes cycling, I’m not getting 2 minutes back running.
I would argue instead, that if you bike just below threshold and run right at or just below threshold, that you paced it perfectly. If you cannot run near threshold after biking at 90% for 60 minutes, then your training load overall is lacking.
Look at some scenarios, lets say on a given course, I’m well rested and can ride a 58:00 at lets say 93%. I can then get off and run a 36:00 flat. Right at threshold pace. So now I back off to 90% and ride a 59:30 (~10W difference). Can I run a 35:30? Uhh…ya right, think again. Honestly, I just don’t think I can go 95 or 96% after a hard swim. So for me at least, it’s a non issue.
I think the scenario most run into is more like this… They ride a conservative 1:08 instead of 1:06, and can run 40:00 instead of blowing up and running 45:00. So 2 minutes saved them 5. If your prone to blowing up, that a little difference that sub optimal pacing. I would also bet that they below up because they tried to run a 40:xx when they only had the fitness for a 42:xx.
Interesting you your time example. I am one that bikes hard, but will not or cannot leave in on the course, and do ride around a 1:08. Then I try for the 40:xx while I see some that have had a faster bike split,
but I say nice race to them as I am passing on the run. Just need to find the best balance to get to the finish like the fastest, which is all that matters.
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