Thoughts on Marathon Training while staying somewhat Bike Fit

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    After being a cyclist for my primary sport for about 4 years, I have decided to get back to doing some more Half and Full Marathons. I love cycling and want to incorporate cycling into my marathon training in order to continue to enjoy both biking and running. I have applied the Master’s Level marathon plan to my TP account (love this new option!!) and have built up to the recommended running prerequisites before starting the plan.

    Here are my thoughts:

    1. Cross Training days – do an endurance ride.
    2. Keep all ‘Long Runs’ as scheduled. Replace the weekend and/or a lower intensity shorter run with an endurance ride.
    3. Each week, on a rotating basis, replace one of the intensity work outs with a similar type of work out on the bike.
    For example: Threshold run with a similar threshold ride one week, Anaerobic run with a similar Anaerobic workout on the bike then next week etc. — Keeps me sharpish on the bike, still builds carido fitness and even less running injury prone.

    I would appreciate any feedback/advice/similar experiences.


    • This topic was modified 1 year ago by gravelGP.

    I’m my opinion, this is a great way to stay fit on the bike but it won’t get you the results you are looking for with the running. If your goal is to just finish the marathon, you would be well with this plan generally.

    However, bike fitness and run fitness are not the same. You won’t have the same perform gains on the run and may not be adequately prepared physically for the long runs. The run workouts utilize different muscle groups than the bike uses.

    If you are primarily concerned about maintaining peak bike fitness and are short on time, this might get you across the finish line but it will be just a finish. If you are looking to race the marathon, you will most likely need to find some time or sacrifice some bike fitness.

    It’s going to come down to you and your goals.

    80/20 Certified Coach


    Thanks Gerald I appreciate your response.

    I get the specificity issue and expect to lose some bike fitness in exchange for increased running fitness. At this point I am looking for a finish and not a race. Looking to enjoy both activities this year without a lot of pressure to perform, and then see where it goes in 2024, maybe a Full IM… got the half checked off about 7 years ago.


    I tried the substitution route last year and it really didn’t work for me, my legs on running days were never sufficiently recovered. This, even though cycling intensities are reduced (if you do a direct substitution from the subscription workout library).

    I am about to enter a master running plan. After some experimentation during a break I’ve concluded that for me it’s better to stick to doing the cross-training as incorporated in the plan. This means just aerobic efforts.

    For cycling I train on Zwift and like several of their low intensity rides with structured cadence changes. My favorite is the Sarah Martin All Rounder. I’ve found that these type of workouts don’t interfere with running.


    Hey Greg,

    I just saw this.. so I have made something like this work before, but it was not with an 8020 Endurance Plan. Before I switched to 8020 Endurance for triathlon, I trained for a marathon using a different plan which had me running 3 days a week and then doing 2 days of HARD bike interval sessions and 1 day of a very long endurance ride (Century Saturdays).

    It was a completely different philosophy to 8020 as the 3 runs were: a hard tempo run, a hard interval track session, a long run at much faster pace than is typical.. The long run was basically marathon pace + 30 seconds, and every week I’d cut off 5 seconds off pace. It was all hard, hard, hard. The long runs were basically all 18 or 20 miles so my running volume was still about 25-30 mpw.

    Did it work? Absolutely, I went from 5:45 to 3:40 marathon and I got stronger on the bike at the same time. However, it was extremely taxing and I have read this plan has a high injury rate. I am relatively young (early 30s) so it worked for me. I much prefer 8020’s methods.

    I will also say that I doubt you will lose as much bike fitness if you just focus on running. It comes back surprisingly quick. I did IM California last year in October and my FTP was ~255W, then focused on running for 3 months and did very little cycling. Tested FTP in January and it was down to ~250W but also while gaining 3 kg. Put in 4 weeks of bike interval training, tested again in February and hit 270W. while dropping 1.5 kg.

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