Cycling for Runners: Can You Build Endurance Without More Running?

Can swapping a run for a bike ride improve endurance while reducing impact? Ultra running coach Paul Tierney explains how cycling can complement running, particularly for trail, ultra and older runners.

Cycling for runners can be an effective way to build aerobic endurance without simply adding more running miles. Whether you’re looking to increase your Zone 2 training, reduce the impact of additional sessions or prepare for the long climbs of a trail or ultra race, cycling can provide a valuable complementary training stimulus.

For runners, the obvious way to improve endurance can seem simple: run more. But adding more running isn’t always the best option, particularly when recovery or the demands of everyday life limit how much training your body can handle.

That’s where cycling can become a valuable training tool. Research suggests that some aerobic adaptations can transfer between running and cycling, while the lower-impact nature of cycling gives runners another way to increase their overall endurance workload.

Speaking on the VOOM Performance Podcast, ultra running coach and running rehab specialist Paul Tierney explained why he increasingly sees value in using cycling alongside running, particularly for older runners and athletes trying to balance endurance gains with recovery.

Is cycling good cross-training for runners?

Yes, cycling can be a useful form of cross-training for runners, although how useful it is depends on the athlete and what they’re training for.

During the podcast, Paul was asked a listener question from Matt, a 58-year-old ultra runner who wanted to know whether cycling could provide additional Zone 2 training volume while reducing some of the physical stress associated with running.

Paul’s answer was straightforward:

“Of course.”

He explained that his own attitude towards cross-training has changed as he’s got older.

“I can see the benefit now of adding something that isn’t as impactful on your body.”

The key isn’t necessarily using cycling to replace running completely. Instead, it can provide another way of adding aerobic training without every hour of endurance work needing to come from running.

And there is research to support the potential for crossover.

A 2026 systematic review and meta-analysis examined randomised controlled trials comparing running and cycling training. Across the studies included, researchers found no statistically significant differences between running and cycling interventions for changes in treadmill-measured VO₂max, cycle-measured VO₂max or running performance [1].

However, the researchers were careful not to conclude that running and cycling are completely interchangeable. Only seven studies met their criteria, the training protocols varied and several studies had methodological limitations [1].

So the evidence supports cycling as a potentially useful endurance-training tool, but not as a perfect substitute for running.

Can cycling improve running endurance?

Running and cycling aren’t identical, and the principle of specificity still matters. If you want to become a better runner, you still need to run.

However, both are endurance activities that place significant demands on the cardiovascular system.

Research into cross-training has long suggested that aerobic adaptations can transfer between exercise modes, particularly when developing VO₂max, although the degree of transfer depends on factors such as training status and specificity [2].

Paul gives the example of replacing a second run with a bike session:

“Throwing a bike in instead of a second run or something like that makes a lot more sense to me nowadays than it would have back then.”

Importantly, you’re still training.

“I feel like I will not compromise the next day’s training as much if I do something with a little bit of a lower impact and it’s obviously still a stimulus.”

An earlier study in moderately trained runners provides an interesting example. Researchers compared five weeks of run-only training with a programme alternating running and cycling. Both groups improved treadmill VO₂max and 5,000m and 1,609m running performance, with no significant differences between the groups [3].

For runners struggling to increase weekly running volume, cycling can therefore offer another way of adding endurance training without simply prescribing another run.

Cycling vs running: what’s the difference?

One of the biggest differences is mechanical load.

Running involves repeatedly contacting the ground and absorbing forces with every stride. Cycling removes those repeated foot-ground impacts, producing a different mechanical stimulus.

That doesn’t automatically make cycling “better” or mean that it prevents running injuries. It simply means that the two activities load the body differently.

This distinction becomes particularly useful when considering total weekly training.

Imagine a runner who can comfortably tolerate four runs per week. Adding a fifth run might provide additional aerobic training, but it also introduces another session of running-specific loading.

Adding a bike session instead could allow that athlete to increase their aerobic workload without simply adding another running session.

Research suggests this can still provide useful physiological training. A study of experienced runners comparing four weeks of run training with a cycling-based cross-training intervention found similar maintenance or improvements in several physiological and performance variables, including ventilatory threshold and 5,000m performance [4].

For Paul, this alternative becomes increasingly attractive when recovery is a limiting factor.

Is cycling particularly useful for older runners?

This was the context behind the original listener question.

As athletes get older, they may find that the training they tolerated 10 or 15 years ago isn’t necessarily the training that works best today.

Paul uses himself as an example:

“If you look at people’s training, say even let’s just take myself from 15 years ago versus now, I can see the benefit now of adding something that isn’t as impactful on your body.”

That doesn’t mean older runners should automatically run less.

Instead, cycling provides another option.

If adding another run compromises your ability to complete tomorrow’s training effectively, substituting some of that volume with cycling may allow you to continue developing aerobic fitness while changing the mechanical demands of the session.

For masters runners and older ultra runners in particular, that balance between training stimulus and recovery may be useful.

However, it’s worth making an important distinction: the research discussed here supports the general crossover between running and cycling, but doesn’t establish a specific rule saying that older runners should replace a particular amount of running with cycling.

The decision still needs to reflect the individual athlete.

Can cycling replace Zone 2 running?

This is where the answer becomes more nuanced.

Cycling can certainly be used to accumulate low-intensity aerobic training, but a Zone 2 cycling session isn’t identical to a Zone 2 run.

Heart rate, muscle recruitment and perceived exertion can differ between sports. Your cycling training zones therefore shouldn’t automatically be assumed to be exactly the same as your running zones.

More importantly, cycling doesn’t provide all of the running-specific adaptations you get from actually running.

This is where the principle of specificity becomes important. Earlier reviews of cross-training research have found evidence for transfer of VO₂max adaptations between different exercise modes, but have also concluded that cross-training effects generally don’t exceed those achieved through sport-specific training. Specificity appears to become increasingly important in highly trained athletes [2].

The 2026 meta-analysis reaches a similarly cautious conclusion. Although researchers didn’t find meaningful differences in the running-performance outcomes analysed, they emphasised that this shouldn’t be interpreted as proof that cycling and running are completely interchangeable [1].

So rather than asking whether cycling can replace Zone 2 running, it may be more useful to ask:

Can cycling help me increase my aerobic training without adding more running than I can recover from?

For some runners, it may.

Why cycling could be particularly useful for trail and ultra runners

Paul makes an interesting distinction between road and trail running.

Cycling could complement training for either discipline, but he suggests it may have particular relevance for someone preparing for a hilly trail or ultra race.

“The bike is probably even more relevant to someone who’s going to be yomping up very steep hills versus someone who’s training to do a fast road marathon.”

Why?

Because steep uphill movement changes the demands of running.

During a long mountain race, athletes will often spend considerable periods hiking rather than running. Compared with faster running on flatter ground, steep hiking can become more muscularly driven.

Paul explains:

“Hiking uphill on foot as part of your training for long trail races is a much more muscularly driven thing than say running on the flat, where there’s a lot more elasticity involved.”

That creates an interesting potential role for cycling.

Can cycling help with uphill running?

It isn’t exactly the same as hiking or running uphill, but certain types of cycling can begin to replicate some of the muscular demands.

Paul specifically highlights high-gear, low-cadence climbing.

“In a high gear, low cadence uphill on a bike, it’s not massively dissimilar to doing something like that on foot, uphill.”

It’s important not to take this comparison further than the evidence allows.

The cross-training research supports the potential transfer of cardiovascular adaptations between cycling and running [1–3], but that doesn’t establish that low-cadence cycling directly reproduces the physiological or biomechanical demands of steep trail running.

It’s better viewed as a complementary training stimulus rather than a direct replacement.

If your race involves several thousand metres of climbing, you should still train on hills and develop the ability to climb efficiently on foot.

But cycling can supplement that training.

For someone preparing for a mountainous ultra, a hilly bike ride could provide a substantial cardiovascular and muscular workout without requiring every endurance session to be another long run.

Can cycling replace a recovery run?

Potentially, but the purpose of the session matters.

If your recovery run is primarily intended to provide some easy aerobic movement between harder sessions, an easy bike ride could provide aerobic training while avoiding another running session.

For example, an ultra runner might complete a long trail run one day before using the bike for easier aerobic training the following day.

That’s close to the example put to Paul during the podcast: could an athlete complete their long run on Friday and then cycle the following day rather than completing another run?

Paul’s response suggests that this can be a sensible option when the goal is to continue building the aerobic engine without unnecessarily compromising subsequent training.

However, if a particular run has an important race-specific purpose, replacing it with cycling may mean losing some of that specificity [1,2].

It’s about understanding why the session is there in the first place.

Should ultra runners cycle?

For ultra runners, cycling can be particularly useful when it allows you to add productive training that you otherwise wouldn’t tolerate through running alone.

It could be considered when:

• You’re struggling to recover from your current running volume.
• You want to increase low-intensity aerobic training without adding another run.
• You’re returning from a period of reduced running and want an alternative endurance stimulus.
• You’re an older runner finding that consecutive running days require more recovery.
• You’re training for a mountainous trail race involving significant amounts of steep hiking.
• A bike session allows you to train while arriving fresher for an important running session the following day.

That doesn’t mean replacing every easy run with a bike ride.

Instead, think of cycling as another tool available within your ultra running training plan.

Running specificity still matters

Perhaps the biggest mistake would be assuming that because cycling develops cardiovascular fitness, you can prepare for an ultra almost entirely on the bike.

Research suggests some endurance adaptations transfer between cycling and running, but it also reinforces the importance of training specificity [1,2].

You still need to prepare your body for the specific demands of running.

Paul makes this distinction when comparing a mountainous trail runner with someone targeting a fast road marathon.

Cycling may have some useful crossover with steep climbing, but a road marathon requires the athlete to tolerate thousands of running strides at a sustained pace.

The closer you get to race day, the more important it becomes that your training prepares you for the actual demands of your event.

For a mountain ultra, that could include long trail runs, climbing, descending, hiking and practising your race-day nutrition alongside supplementary cycling.

For a road runner, running itself is likely to remain an even greater proportion of the overall endurance workload.

More training doesn’t always mean more running

Perhaps the most useful way to think about cycling for runners is that increasing your endurance training doesn’t always have to mean increasing your running.

The latest evidence is encouraging. A 2026 systematic review and meta-analysis found no statistically significant differences in changes in VO₂max or the running-performance outcomes studied when comparing running and cycling interventions [1].

But there’s an important caveat: the researchers themselves stressed that the evidence remains limited and doesn’t prove that cycling and running are interchangeable.

That’s why Paul’s approach makes sense in practice.

Cycling isn’t there to replace the running you need to prepare for your race. Instead, it gives you another way to create an aerobic training stimulus when simply adding more running may not be appropriate.

As Paul puts it:

“I will not compromise the next day’s training as much if I do something with a little bit of a lower impact and it’s obviously still a stimulus.”

For older runners, athletes managing high ultra-running volumes or runners preparing for particularly mountainous events, that can make cycling a valuable addition to the training week.

Sometimes, building endurance doesn’t have to mean running more.