15 Comments

Hi Gordo,

I continue to circle around re-reading your Substack and Twitter, learning new things - thank you.

My context: I’m a competitive amateur runner. I have a good grasp of my run and bike zones by HR and pace/power and an indoor bike trainer.

Questions:

1) What is a good rule of thumb for figuring out the bike substitute for a Z2 or Z3 run? E.g., if I otherwise would do a 50:00 run in Z2, should I match that with a 50:00 Z2 bike? Or 1.5 or 2x as long on the bike (75:00 or 100:00)? Or is it based on TSS equivalency?

2) Are there any advantages to an athlete’s development as a runner by using Z3-Z5 bike workouts from a duathlon training plan?

Or should a runner, in general, stick to the bike for Z0, Z1 and Z2 metabolic fitness efforts and not use it for Z3-Z5?

I know you have shared ingenious use cases where the bike can be used to aid running specific capacity. E.g., the SART for testing run readiness, and your spin-ups help runners who lack good turnover or who don’t have good musculoskeletal durability, etc.

If you have the occasion to address any of this, it would help me refine my mental model of cross-training for runners - thank you.

Interestingly, I see that cross-training is getting a bit wider acceptance. It was fascinating to read that this year’s NCAA women’s D1 XC champ, Parker Valby, runs just 3 times a week, using cycling, a more evolved form of an elliptical machine and swimming for her other workouts.

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These are good questions.

1) I see bike and run as complementary, not substitutable. So you want to get your run workouts done as the core part of your run program. The bike is supplemental volume that supports general fitness for running. The bike lets us get more overall volume completed, than running alone.

2) More generally, your questions could be phrased as... where is the best place for a runner to schedule their intense training? The answer is "it depends" If you tolerate the intense training (Core Pace, Red Zone) on the run then, as a runner, it's best placed there. If you're not tolerating your faster running then other modes, and terrain, can be used as a substitute. However, "not tolerating" is a sign that the overall stress load is too high. So step back and take a look at what's up with the overall program and what's happening outside of training.

Use cases for higher intensity on the bike...

A) A race simulation workout with less overall stress. A bike is placed before a Core Pace run to make the overall duration of the combination workout longer. Still gives a look into Core Pace performance, recovery is quicker, and duration is longer to check nutrition. It's about the only way most runners can train marathon duration without extended recovery.

B) Triathlete breaks down with sustained running. Use long climbs (bike) for Tempo (Z3/Z4 border). Use short climbs (bike) for Z5 work. Gives the cardiovascular adaptations from intensity, without injury risk. Overall run program stays Green Zone with Strides for quickness. Shorter, C Priority races are used as high intensity sessions. Worked great for an older Ironman triathlete I coached - world class for his age.

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Big Picture

To start... the bike is supplemental to the core running program that the athlete is already handling. This takes the pressure off the athlete to constantly push run volume upwards to breakdown (very common). Also allows more overall aerobic training.

Then... look at what the runner needs and tolerates for their more specific work. That's going to be largely run focused. When it's not tolerated on the run... consider if the bike can be used to support their physiological needs.

g

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Dec 15, 2023Liked by Gordo Byrn

Gordo, this is so useful, thank you. My previous mental model of your cross-training ideas was helping me a lot, but this helps me revise it to work even better. I really appreciate you taking the added trouble to provide further use cases for Z3-Z5 on the bike; they are practical and help me consolidate my understanding of a lot of your ideas & implementations.

Thanks again

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Nov 24, 2023·edited Nov 24, 2023

Hi Gordo. New subscriber, loving your writing and video content.

Can you share any advice on the bike/smart trainer setup you recommend for someone coming to road cycling for (almost) the first time, wishing to do the bulk of their training inside with the occasional outdoor ride? I'm currently a marathoner managing ok with the run volume and I ride a mountain bike for a work commute every now and then. Cheers, and thank you!

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DC Rainmaker has excellent reviews of all your smart trainer options.

Black Friday deals are likely still rolling:

https://www.dcrainmaker.com/?s=smart+trainers

For road bike - your best value will be a used bike with traditional shifting (not electronic). The group sets are so good these days, that will work just fine. For indoor riding, a basic bike will work great.

Most of the trainers are cassette specific - meaning you need to match the number of rear gears between the bike and the trainer.

Zwift makes a universal trainer that matches up with any set up:

https://us.zwift.com/pages/trainer-comparison

I bought one for myself yesterday - the Zwift Hub.

g

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Hi Gordo, I live in a hot place and I'm wondering about this: is lactate always and absolutely linked to heart rate? For example, if I run on a very hot day my pulse may be 10 beats higher for the same route. In this case, can I move the limits of my training zones accordingly (5/10 beats)? Can I assume that the higher strain on the cardiovascular system is only due to body cooling, and not to a general physiological effort?

So, can I do a lactate test on a 30 degree day, or would it be compromised? Thank you!

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Interesting article, but definitely out of my league. Ultimately, I just want to understand whether it makes sense to test lactate during hot weather or not

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I think it makes sense.

I'd give yourself at least 14 days of hot weather acclimatization before testing.

G

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Nov 14, 2023Liked by Gordo Byrn

Perfect, thank you! Acclimatization is not an issue, we are in spring right now with summer approching: it's just a gradual change.

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Thanks, I was just replying your answer of yesterday! Coming soon

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"Zones in the heat" deserves its own article. I'll make a note.

Question for you, have you noticed an adaptation period with the change in temps?

What I find is there's a short term pop, when heat increases, then I'll trend back to normal.

For me, a 5bpm upward shift would be ok but 10bpm would be too much. I'd notice because my recovery would be extended. So look to how you tolerate the heat change.

Also, all zones must be adjusted based on environmental reality. There's what we can do on a cool day and what we can do in heat/humidity.

Testing: after you've acclimatized, useful to test. Be aware that lactate is a concentration metric. If you are dehydrated then that will impact the lactate reading (and heart rate). Easiest to see this when comparing normal baselines.

Early season heat... Back off and give time to get acclimatized.

Personally, training through Hong Kong summers and Thailand/Singapore (anytime)...I was a heat avoider. I never went looking for extra stress as I knew I was getting plenty in my overall program. After a few weeks, my HR zones would be consistent so long as I wasn't in direct sunlight, which elevates because it's so tough to shed the excess heat. Clothing choices, and staying wet, helps in all but the most extreme conditions (where significantly slowing down is what's required).

G

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As for the adaptation period, that's not the point: I'm simply entering the warm season, so it's a slow and gradual change that doesn't need to be taken into account.

What I would really like to understand is whether lactate values are always linked to heart rate, or whether they are somehow affected by body heat.

I only got the device in February, and in these months of use I have seen huge differences in baseline values depending on my physical condition at the time. This surprised me a lot! In fact, I believed that lactate concentration depended almost exclusively on the physical effort of the moment. Instead, I noticed that it is extremely sensitive to other physical factors. I therefore wonder if ambient heat and consequently body heat can distort the values of a lactate test.

This is to find out if it makes sense to continue testing myself even during the summer, when it will be 30 degrees here...

As for everything else you write, it's all clear and very useful, thank you!

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I think it's worth building a profile across the summer.

It's normal to see movement for the factors you note - fatigue status, nutrition, fed vs fasted, hydration status, exposed to a virus (or not)...

g

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Thanks Gordo 🤗

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