Marathon training only on a bike

This is clearly a troll post. The OP said "thanks for the great advice" then gave up. He didn't want all these serious replies. 1/10 super fail.

I ran a trail marathon not having run in over a year while working as a bike messenger. I finished but it was awwwwwwwwwwwful.

I trained with about 35-40 miles of running and 75-100 miles a week of high intensity biking (avg watts 225-240) for the myrtle beach marathon (flat). Was in pretty good shape and did my last long run of 21 miles at sub 7 minute miles on rolling hills. Thought i was in sub 3 shape (will never know). 10 miles into myrtle beach i pull my calf. No running for 5 weeks but after one week of nothing i was biking 150 miles per week. At the end of the 5 weeks i run 13 miles at 7 minute per mile pace. 6 days later i ran a local low key marathon that i did not know was hilly to still try to get a boston time.

Was good for 18 miles but like others said my legs could not take the pounding. Was literally walking on the down hills as my knees and quads were shot. Went through the half in 1:29 and finished at 3:13. It was UGLY for the last 8 miles.

Long story short biking can compliment your run training but you will still need a solid run base to acclimate your legs to the pounding. Also like running, intensity on the bike is important if you want it to provide run benefits. A general rule of thumb i have heard from a few sources if you an not experienced on the bike you should try to get your HR to about 10 bpm's of your run hr. If you are new to the bike 10 bpm's.

Good luck what ever you decide please share how it goes.

It can be done but it's gonna hurt:)

I'd definitely try to get your legs use to hitting the pavement. Make the runs hard ...1 tempo fast finish, 1 intervals 5x2 miles, 1 longish easy with some hills....repeat every 7-9 days that cycle...

If you can do that for 6 weeks and ride for the rest you'll be ok but your gonna suffer around 15 miles... and probably walk it in. You might be ok but my guess is the concrete will win after 15 miles and you crumble.

I have run some fast marathons on low mileage but you still need 2-3 sessions per week that are abusive and hard. So make the hard days hard... rest on the bike...run some hills...have some fun.

I basically did the OP's plan. I biked around 200 now and ran 10-20. I felt great for the first half of the marathon. Then not great. Then excruciating pain every time my feet touched the ground. My knees were swollen for the next two months.

I finished in a little under four hours. Cardiovascularly, I felt pretty good, and could have pushed harder, but my knees were absolutely not prepared for the pounding they were going to take. You can't train for that part on the bike no matter how much you ride.

That durian rider guy is annoying AF.

Life long runner (now jogger). Did my first ever half marathon last year at wdw in about 2:45. I was 60 last year. The course narrowed at several points at wdw so I was forced to walk a couple of times due to the bottlenecks and some of the walkers were 6-8 abreast so you had to slow way down, stop (walk) or bully your way through at a couple of spots. I've had 2 knee surgeries and am holding off on the 3rd one as long as possible. I trained mostly on my bicycle and over the last 6-8 weeks increased the running mileage and tapered the rides. I'd always run 3-4 times a week as I was training but the runs we're 3-4 miles each time. The last 6-8 weeks I'd run 3 days a week with a 3-4 mile day, 6 mile day, and a long run of 9-10 miles. Recovery after the 10 mile day was much easier if I went on an easy ride the day after (12-15 miles). My goal was a sub 2:25 and I felt I would have reached that milestone without all the traffic

My wife, likewise did her first half marathon last year. The most running she every did was HS tennis. She started off walking and jogging. Jog for 30 seconds/walk 60. If she didn't stop for all the character pictures at disney she would have easily finished with me. This year she'll surpass me unless she stops for the character pics again....which of course she will.

Mid 40s here and I follow a tri program

On a whim I did the SF marathon and just snuck under 4h

My open half at the time was 1:40

Program was 50-60 mpw biked

20 mpw run (including standard long runs, did push high weeks up to 30 something to accommodate the 14-18ers in my program)

Swam 6k yards/week

So not a lot, and I got injured from the marathon for 4 months with a serious hip thing, as a result I no longer do thon training, but focus on 70.3s, olys, 5ks, and swim stuff

Don't ever run a thon on such low mileage unless you like getting hurt. I thought several years of tri training and 70.3s meant I was tough, maybe in a 70.3, but nothing was there to help in the thon. I actually went super slow (9:00/mi) so I guess that's why the thon was easy. Spending the next four months wondering if I'd ever be able to run again wasn't fun tho

Back in 2000 I ran 2.57 off typically 3 days of running and lots of bike riding. I was 40 and the race was the 20 th anniversary of my last 3 hr plus marathon (3.01).

I had 3 schoolage kids and both my wife and I had pretty hectic lives.

I commuted by bike so was racking up 20 to 40 kms most days on the bike. I did a long run of 2 hrs plus over hilly cow paddocks on Tuesday after getting the kids to school and before commuting to an afternoon shift on the bike.

Thursday I could squeeze in 15 or so minutes of running normally. That would typically include 1.6 km at 5 km pace and maybe a couple of fast 400s.

Sunday morning was a 5 to 10 km race

I ran 37.18 for 10 km the week before the marathon.

My marathon pb from 1984 was 2.43 off plenty of kms (often 160 km weeks) and I had run ultras in my 20s and 30s.

Depends how you are going to split those 200-250 bike miles. It's doable and painful as hell. Here is what I recommend you(similar to triathlon but without the swimming):

Since by cycling you won't get your legs used to the pounding a marathon brings, if you are biking around 36 miles a day (I am assuming that 250/7=35.7) Right after each of those 35 mile bike ride , go for a 5k run, or anytime you complete a long bike ride.

Why? Brick legs. The brick legs effect after the bike ride will train your brain and legs to the PAIN of pounding. But there is a caveat: The bike mileage should be done at 70-80% Max/HR.

This weird method has worked for me at least for half marathons (back in February clocked 1h:27:00 in the half on 2 hour bike rides followed by a 5k run one day on - one day off, on average 4 or 5 times a week.) For a full marathon, I recommend to do 3 hour bike rides followed by the 5k run.

Good luck!