I’m focusing on training for my 5th marathon right now. I have almost given up cycling/swimming to focus on my running. I’d like to average about 50 miles/week, but I can’t seem to do it without overtraining (too much stress). I do usually cycle 1 day a week (about 45 miles). I’m trying to figure out a rough equivalency of “running miles” I should count my cycling as.
If it takes me around 3-3.5 hours for the bike ride (hills) and it’s a pretty easy pace I must be getting some running benefits, yes? But not as much as running 3 hours.
So far I’m averaging about 35-40 miles/week running. My previous marry PR is just under 3:25 I’m shooting for 3:10.
I was once told that to figure out cycling to running that you should divide by 4 (and for swimming to running multiply by 3) to get the equivalent exercise. I don’t know of any scientific study or anything to back this up, but when I first started doing tris a kinesiolgy student/friend of mine gave me this info so I could relate my swim and bike to running, which was what I knew.
Actually, from both an energy expenditure and time/effort point of view, I think the ratio is closer to 2.5 to 1 - though it will likely vary somewhat according to one’s personal efficiency in each of the disciplines. As a personal example, sub-max biking at a 20 mph non-drafting pace feels for me roughly equivalent to running at a 7:30 pace. And at the red line, my best time trial time for 40K was in the high-58 range (25.5 mph), while my best time for 10 miles was just over 60 minutes (10 mph).
If one looks at world records, the same general ratio holds. The speed for the hour record on the bike is in the 32.5 mph range, while the best runners in the world do a half-marathon in about the same time (ergo 13.1 mph). 32.5/13.1 = 2.48.
At the longer distances, Yiannis Kourous ran (at age 41) 188.6 miles in 24 hours. If I remember correctly, the solo, non-drafting, loop-course 24-hour record on the bike is somewhere in the 520 mile range. 520/188.6 = 2.76 - but the widening of the spread over time probably has to do with the pounding effect experienced by runners but not by cyclists.
I can tell you that these old bones would much rather do a three hour bike ride, say 50 miles, than a one hour run, say seven miles. This is more like seven to one. If I could do my run training by cycling, my running wouldn’t stink so badly.
Sorry, the only thing that helps my running is running. The other sports help my fitness so I can lay off running for a couple weeks without backsliding, but they are just place holders at best.
When I am concentrating on running, I think of days that I only bike or swim as days off. It is OK to take days off, maybe even necessary, even when you are concentrating on running. Guys with fewer running problems or injury problems or recovery problems can probably trade off a lot better than I can.
From a caloric expenditure point of view…it looks like your 2.5/1 is pretty close. For my weight, a one hour bike ride at 19 mph is supposed to burn roughly 1080 calories…about the same as a one hour run at 8 min./mile pace (7.5 miles). That would be about 2.53 cycling miles for every running mile. I don’t know, I’d much rather ride 19 miles than run 7.5! Interesting.
There can be more to it than just a run:bike substitution - fortunately.
I worked last fall with an on-line coach - with whom I had worked before - and I asked him for a program that would use the bike to hold down my running mileage to avoid injury. The mix that he used was fascinating, but I’ll stop there.
Results were great, until the onset of a lung ailment ten days before d-day. (Must not have been overtraining, as I’m still struggling 5 months later.) However, the time trial that I ran as an assesment three weeks before the race made us both go “wow!”
I don’t know if this is what you are asking, but I use 4/5 miles biking = 1 mile running
26x4=104 miles biking 26x5=130 miles biking so the average would be 26 miles running =117 miles biking. I don’t know where I got this but I read it years ago