[mountainbiker]

I find that the foundational Z2 part of training to be somewhat boring if I just stick to one activity, especially during the winter when it is easier to run outside than to ride outside. So I typically like to mix indoor cycling with running.

But I am wondering: Is a 1 hour run in Z2 the same as a one hour ride in Z2 in terms of aerobic conditioning? Or do I need to adjust my time windows depending on the activity to equalize the amount aerobic conditioning that I am getting? I find that I can ride much longer than I can run because I am primarily a cyclist and running beats up the body. Thanks.

[Gerald]

Bike and running should match minute for.minute at the same.zone.

My only caution is to establish your zones for the bike as they could be different than your zones for running

[mountainbiker]

Thanks Gerald. That’s what my gut told me so I’m glad it’s confirmed.

[Matt Fitzgerald]

Running is more stressful to the body than cycling is. In making these conversions it’s helpful to look at TSS (training stress scores) on TrainingPeaks. The cycling equivalent of a Zone 2 run of any given duration will be about 20 percent longer.

[Gerald]

Thanks Matt. I have made note for my own records as well.

[mountainbiker]

Thanks Matt. Appreciate the info.

[maddenap]

If my understanding is correct based on the above discussion, if I choose to do a bike ride in zone 2 to replace a foundation run, I need to ride 20% longer to get the same benefit. If that statement is true, how does this reconcile with the cross-training information that states people have the option to “replace any Recovery or Foundation Run with a nonimpact cardio alternative of equal duration and intensity[?]” Shouldn’t the cross-training documentation be updated to say if you choose to bike, you need to do it 20% longer? And similarly, what about other forms of cross-training? Do the times need to be adjusted?

Am I overthinking this and/or interpreting wrong?

Andrew

[Matt Fitzgerald]

That’s just it–each modality is different, so we either provide a specific recommendation for everything under the sun or we offer a good-enough blanket recommendation, which is what we do. Also, the general expectation here on our side is that most athletes will exercise this option on an ad hoc basis rather than routinely. In the case of someone who wants to replace EVERY Foundation Run with an Easy Ride, I would suggest they increase the duration a bit if they have the requisite motivation. But that motivation can’t be assumed, and it should be pointed out that a 20% difference in weekly CYCLING time will have a tiny impact on performance in RUNNING races.

[BrianNSC]

Matt – I realize this might be “putting too fine a point on it”, but for other cross training activities that are recommended in your books (namely, standup cycling-like elliptigo, and incline walking) would that ratio be closer to 1:1?

I do a fair amount of that type of crosstraining, up to 25% of my total volume, and I therefore like to assume I’m getting more benefit than I would on my road bike for example.

[Matt Fitzgerald]

It is truly case by case, and I don’t know the answer for some modalities. ElliptiGO has been studied and it is close to 1:1. But all of this assumes that the training load administered by the plan as written is 100% perfect for you individually, which is highly unlikely. We sell plans in four levels. Are there exactly four levels of athlete? No, there are not. Which is okay, by athlete/plan interactions function as complex dynamical systems. Hence, if the training load administered by the plan you’re following is a bit too low, you’re going to have extra energy that you invest in the plan by going a little harder. But if the training load administered by the plan is just a bit high, you accumulate extra fatigue that causes you to do everything a little easier, which has the effect of fine-tuning your plan in the other direction. My point is that the plans are “horseshoes and hand grenades” to begin with, so when you’re replacing runs with cross-training sessions, it’s just more of the same. All efforts to find the mathematically perfect substitution assume the training load was mathematically perfect for you in the first place, which it wasn’t, which is okay.

[Charles]

At the risk of exposing my ignorance, isn’t 80/20 defined by ratio between below and above lactate threshold?

I recently introduced indoor cycling as a component of my training, primarily to develop local muscular endurance for running and as a substitute for running when necessary.

When I cycle I don’t come anywhere near my HR for running. When I am running I am using all of my body to generate the power, when cycling I am probably using 35% of my body to propel myself. I can get a “nice’ burn training above threshold in the lower body, and yet the overall impact is aerobic. The price is in the recovery.

Apples and oranges. I never liked the term cross training for this reason. My personal take is that cross-country, treadmills, trail running etc. is cross training and anything else is goal based training.

In this context, when cycling as a substitute for a foundation run it makes perfect sense to reduce the cycling intensity and extend the duration to achieve a desired aerobic training effect as Matt has pointed out here and elsewhere.

[Matt Fitzgerald]

Close. It’s actually the first ventilatory threshold (VT1) that partitions the 80 and 20 parts of 80/20. The lactate threshold aligns with the top of Zone 3, the VT1 with the top of Zone 2.

[mulk]

What about swimming and xc skiing? Are there any rules length for them?

[Matt Fitzgerald]

Swimming varies widely based on individual ability. Poor swimmers expend vastly more energy than efficient swimmers. Cross-country skiing is more energy-intensive but less hard on the body overall, so I’d go with a 1:1 ratio there.

[mulk]

Thank you for your swift response, Matt!

[Author]

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