Can Cross Training On A Bike Translate To Better Running Performance?

Picture from Bikatadventures.com

I had shin stress fractures in both legs from running too much when I was 20. The doctor I saw said that I could not run for a minimum of 6 weeks. I could only swim or bike. It was this cross training regime that got me started in triathlon later.

This concept cross training emerged in the 1980s along with the popularity of triathlon. Earlier studies reported that performance in a primary sport can be maintained despite reductions in volume of the primary sport by training in a variety of sports. These findings suggest potential crossover effects between endurance training modalities. Are these findings still relevant?

The following systematic review by Menges et al (2026) compared the effects of running only and cycling only training interventions to evaluate cross training transfer to sport specific VO2 max and running performance.

The authors found 7 studies with intervention durations of at least 4 weeks. These were run only training with cycling only or combined running-cycling interventions. Outcomes included VO2 max assessed on a treadmill or cycle ergometer as well as running time trial performance for 1 mile, 3000m and 5000m.

So does cross training on a bike help running performance? This meta-analysis suggests it does. The subjects who performed run only, bike only or combined running and cycling training performed similarly in the 1 mile, 3000m and 5000m time trials. They also had improved VO2 max values regardless of testing method (treadmill or cycle ergometer).

Cycling engages the quadriceps and gluteus maximus muscles in ways that running does not. When the muscles get stronger, it helps improve running economy and power (especially in hilly races).

Instead of running twice a day, you can take away some of the extra strain on the legs by cycling (or even training on the elliptical machine) without the repetitive impact forces of running. This is especially beneficial during recovery periods or for runners prone to injuries.

Cycling is low impact which is great for your joints. However, it does little to help your bone density. Running on the other hand has impact loading that helps to maintain or even increase bone strength which is great for older athletes.

The findings should be interpreted with some caution since there were limited studies (7) and the fairly short training period.

For shorter distances up to 5 km at least, there may not be any differences but in a longer event like the marathon, you still need to run since the run muscles will not used as much while cycling. Biking can definitely help the aerobic fitness but not the specific leg muscles, and running performance may decline.

Running and cycling can actively enhance each other when integrated carefully. If you're a runner looking to improve your endurance without extra impact or a cyclist looking for stronger stabilizing muscles, cross training helps.

The key is balancing both to meet your specific training goals while avoiding overuse injuries.

The principle of specificity suggests that cross training can offer general fitness benefits, the most significant performances are achieved through sport specific training. Before Sabastian Sawe broke the 2 hour barrier for the marathon, he was running in excess of 200 km a week in the 6 weeks leading up to London, with a maximum of 241 km (150 miles). 

So, runners and cyclists should incorporate cross training as a supplementary activity rather than a replacement for their primary sport.

References

Menges T, Dindorf C, Dully J et al (2026). Cross-Training Between Rnning And Cycling: Effects On VO2 Max And Running Performance- A Systematic Review And Meta-Analysis. Front Sp Act Living. 8: 1843803. DOI: 10,3389/fspor.2026.1843803

Tanaka H. (1994). Effects Of Cross-Training. Sports Med. 18: 330-339. DOI: 10.2165/00007256-199418050-00005

New Updates On The Effects Of Prolonged Sitting

All on screens while sitting

I first wrote about the ill effects of sitting or being an active couch potato back in 2014. Subsequently, there were more and more research about the negative effects of prolonged sitting, suggesting that sitting is the new smoking. There were also suggestions that not all sitting is bad.

Previously, most of the data suggested that these effects were independent of your exercise habits. Even the fittest people were at risk of heart disease if they spent large amounts of their time sitting in front of desks or watching television.

Now, this is not prolonged sitting

One suggested reason why prolonged sitting is bad is that there is reduced blood flow to your legs. Your blood vessels become stiffer and less able to expand and contract in response to changes to your blood flow. Over time, that makes you more prone to atherosclerosis - a hardening and narrowing of your arteries, leading to heart disease.

Time for an update. New published research from Japan (Morishima et al, 2020) suggests that endurance training might well have some protective effects. There seems to be some differences between the current and previous study.

In the current study, the researchers studied a group of competitive cyclists versus a control group that did no endurance exercise. Before exercise and three hours later, there is almost no change in the blood flow to the legs of the competitive cyclists while it dropped by half in the matched controls.

Previously, another recent study by Garten et al (2019) that showed that endurance exercise had no protection for trained athletes. If you examined the data more carefully, you will notice that the "trained" group had an V02 max of around 50 ml/kg/min. This level is above average for young adults but not fantastic.

Nah, I'm not one of the cyclists in that study

In the latest study by Morishima by et al (2020), the competitive cyclists had an average V02 max of 61 ml/kg/min. This is considered excellent, and they have been training for five years and rode an average of 600 km per week.

The earlier study assessed micro vascular function in the subjects. This refers to the function of smaller arteries that branch off the big arteries and go into the muscles. The current study measured macro vascular function, this is the function of the big arteries from the heart to various parts of the body.

Both forms of vascular function are important. The responsiveness of the big arteries predict your risk of atherosclerosis, while the smaller arteries dictates how quickly and effectively oxygen rich blood goes to your muscles. This is really important for all athletes.

Possibly this may suggest that all the endurance training at a high level protects you from macro vascular function, but not micro vascular function during prolonged sitting. This is good news for your long term health.

However more specific research is needed, so train hard and at the same time try not to sit too long at work or at home watching Netflix. Hopefully with the circuit breaker ending in a few days time, you'll get out to exercise more often.

References

Garten RS, Hogwood AC et al (2019). Aerobic Training Status Does Not Attenuate Prolonged Sitting-induced Lower Limb Vascular Dysfunction. App J Physiol Nutr Metab. 44(4): 425-433. DOI 10.1139/apnm-2018-0420.

Morishima T, Tsuchiya Y et al (2020). Sitting-induced Endothelial Dysfunction Is Prevented In Endurance-trained Individuals. Med Sci Sp Ex. DOI: 10.1249/MSS.0000000000002302.

Great day to go cycling - Mount Faber