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

Health Trends For 2021

Straits Times 1/1/21

Great suggestion in today's Straits Times article on the back page (B16, under Sports section) where the author suggested having more local running events for women.

I say not just more races for women only, but men and those under 21 too. In a year where most if not all running races were cancelled, runners are starved for social interaction and a chance to clock a personal best time for some or be quick enough for that elusive Boston qualifying (or BQ) time.

Perhaps with the rollout of the vaccines making exercising in enclosed spaces safe again, people may still want to go back to gyms, yoga studios and fitness centers etc.

I'm hope I'm wrong for the sake of those businesses, but I think gyms, yoga, Pilates studios may not be totally out of the woods yet. Bike shops, cheap dumbbells and other home exercise equipment will definitely continue to be in hot demand. Since March 2020, where most the world started lockdowns, too many people have learnt how simple, cheap and safe training at home is. 

I'm predicting that running, cycling, long walks and roller blading will continue to be popular in this new year. Let's all recognize the benefits of our local parks, bike lanes, park connectors and green spaces. All these spaces definitely impact our health.

A lot of us started baking, cooking and even growing our own food since the lockdown. All are healthy trends and may we continue to do that.

Let's continue to support our own local communities, the smaller shops and restaurants as they battle to carry on. We bought all our Christmas and birthday gifts from Everyday Vegan Grocer and Le Matin.

Here's wishing all of you a safe, healthy and wonderful year ahead.

How Much Water To Drink After Exercise?

Picture by Daniel Orth from Flickr

I was reading a paper on the 24-hour hydration status in runners after a dehydrating run and testing what measurements are reliable to detect this when I thought of a very funny thing that happened at the Olympics.

As Team Singapore's Physiotherapist at the Beijing 2008 Olympics, other than treating the athletes, I was sometimes roped in to help test our Singaporean athletes' hydration status (since we only had one nutritionist and no exercise physiologist at the games).

Director of High Performance and other senior management at Singapore Sports Council (now SSI) decided that in order to perform well and/ or win medals, our athletes needed to be amply hydrated at all times.

Some of our athletes complained about this rather strongly as they were asked to drink more water when their hydration status showed that they needed more fluids. These athletes complained that after consuming more water they had to get up in the middle of the night to pee and afterwards could not fall asleep again for a long time.

You know what they did? They simply added water to their urine samples to pass the hydration test. Our staff got their testing done, the athletes got their much deserved sleep. Team Singapore won the medals they came to win. Win win situation for all parties. No names will be mentioned to protect the athletes involved of course.

Anyway, back to the study.

The group of runners in the study ran in hot conditions until they lost about three percent of their starting weight on three occasions. The three rehydration protocol was either 3.2, 4.2 or 5.2 litres of fluid over the next 24 hours.

Rehydration in the first 24 hours were assessed by measuring body weight of the runners, urine colour, urine specific gravity (a measure of urine concentration) and reported thirst sensation.

The most sensitive marker for fluid consumption during the first 12 hours was urine specific gravity. (Atago - which measures devices to measure specific urine specificity was used and they also sponsored this study).

Thirst emerged as a very sensitive and reliable marker by the end of the 24 hour period. The problem is that differences in thirst did not appear after the run but only emerged the next morning so you may go to bed not knowing you've not drunk water.

When the runners drank a lot, they urinated more, when the drank less, they urinated less. You may be surprised with this but when food and fluid intake were tightly controlled, the runners' body weight was unable to detect low fluid intake. The researchers concluded that body weight wasn't a particularly helpful way of tracking how much you're drinking.

There were only subtle changes in urine colour when measured on the researchers 8-point scale. So you have to pay close attention to the shade of your urine colour should you choose to to use this cue.

4.2 litres corresponded to replacing about 100 percent of the sweat losses within the first 12 hours of their run and 200 percent within 24 hours. This was sufficient to return the runners to normal by the time they were ready to run again the next day.

Turns out it corresponded most closely to how much the runners would have normally drunk too.


Reference

O'Neal EK, Stevenson MC et al (2015). Hydration Assessment Technique Over 24-h Post-run With Low, Moderate, And High Fluid Replacement. ACSM Annual Meeting. May 28, 2015. Abstract here.

With the then Singapore President at the 2008 Olympics

Running Does Not Wear Out Your Knees

Picture by Cameron Drake on work done by Dr Noah Weiss

How many of you have had friends tell you that you'd better stop running as running causes your knee joints to wear out. I've had my fair share too.

Well, now you can tell all the naysayers that running (at any age) does not increase your risk of osteoarthritis (or wearing out of your joints), in fact they may even prevent the condition. This information was presented at the annual meeting of the American College of Rheumatology.

Researchers did a long term study on 2,683 subjects at four stages of their life : 12-18, 19-34, 35-49 and 50 and older. They were classified as a runner at that stage if they listed running as one of their three main activities.

X-rays of the knees were collected as well as subjects' reports of symptomatic pain. The knee x-rays were repeated again two years later. Analyses showed that 22.8 % of the participants who were runners had need osteoarthritis compared to 29.8 % who had never been a runner. And get this, average age of the participants was 64.7 years.

The authors concluded that "non-elite running at any time in life does not appear detrimental and may be protective" in regards to developing knee osteoarthritis.

Reference

http://acrannualmeeting.org/wp-content/uploads/2015/02/2014-ACR_ARHP-Annual-Meeting-Abstract-Supplement.pdf.

Can Running Help Stop You From Eating Junk Food?

My personal favorite

Any of you having a craving for junk food? I do, all the time. In fact as I'm writing this, I am having a huge craving for potato chips.

How do I not succumb to this urge? Well, it seems that people whose brains have a strong dorsal-lateral prefontal cortex (DLPFC) section may have greater self control when it comes to eating behaviour.

What the heck is that?

Well, the DLPFC is near the front portion of your head in case you were wondering. Researchers zapped that area (with a coil placed near the subjects scalps near the hairline) to temporarily decrease brain activity in the DLPFC of the subjects in their study.

Guess what? When the participants were zapped in that area, they had more food cravings and also ate more junk food compared to subsequent tests when they received a sham zap.

With that zap, the participants were almost totally interested in high calorie snacks (Pringles potato chips and milk chocolate in the study).

In fact they mostly ignored the more healthy food options that were also available.

The researchers suggest that improving your DLPFC function can improve dietary self control, prevent obesity and may even help manage Type II diabetes.

How to you make your DLPFC function better? Studies have shown that running and other aerobic exercises are known to enhance DLPFC function. Getting adequate sleep and avoiding alcohol have also been shown to help.

Hmmm, this is strange. When I used to train a lot previously, I would often eat all chips, chocolate, drink lots of Coke etc. I thought all that training was supposed to help strengthen my DLPFC??

Now that I'm not racing and training much I would not dare to eat as much for fear of putting on too much weight. I guess after my accident, I've changed my eating habits as well.

Reference

Lowe CJ, Hall PA et al (2014). The Effects Of Continous Theta Burst Stimulation To The Left Dorsolateral Prefrontal Cortex On Executive Function, Food Cravings And Snack Consumption. Psych Med. Sep 76(7): 503-511. DOI: 1097/PSY.0000000000000090.

Minimalist Running Shoe Fad Over? Or Not Quite...

Minimalist running shoes from Runnersworld.com

Headlines for the running community that you runners may want to know. Despite running shoes sales growing 8 % for the first quarter of 2013, sales of minimalist shoes declined more than 10 % during the same period.

This is in contrast to past few years' quarterly reports where the minimalist shoe category had the highest growth while sales in the motion control and stability segment stagnated or fell.

What drove sales of running shoes this past quarter surprisingly was motion control and stability shoes which grew > 25 % and 10 % respectively. A real reversal of sorts it seems.

An running shoe industry observer even commented that the "minimalist shoe fad is pretty much over."

So, do we take the report as the headlines suggest? That there are decreasing number of runners buying and wearing minimalist running shoes and perhaps even reverting back to the more chunky counterparts?

Well, my personal take on this is, hold your horses. A line from the running report said that "Lightweight, which remains the largest sub category, grew in the low teens." This minimalist (or barefoot) trend has definitely influenced and even resulted in running shoes becoming lighter across the board. Other design elements like low or zero drop midsoles, wide toeboxes etc have been transferred to other shoe categories. The whole running shoe market has shifted toward lighter, simpler shoes to give you, the runner a much wider choice than before.

If you recall, it wasn't that long ago when you went to a running shoe store and your options were pretty much limited to relatively heavy and chunky (> 12mm drop) shoes from brands that was classified as neutral, stability or motion control. Those days are long gone (although many medical professionals here in Singapore who have not kept in touch still insist on those categories) and the market has shifted and studies have shown that the previous model of fitting shoes were not effective.

Probably the most important issue now is how to choose your running shoes given the wide variety you now have.

By the way, I just got a minimalist/ barefoot running inspired shoe for my wife. She loves her new running shoes. A clue that "the fad" is not quite dead yet perhaps?

A pair of Merrell's for my wife

Those of you who work in the Singapore running shoe retail stores may have the latest trends probably, some comments here would be appreciated.

 * Footnote - Nike Free running shoes were not included in the minimalist shoe category as SportsOneSource (the company doing the statistics, SportsOneSource) felt that a lot of people buying Nike Free shoes are not real runners.

* Some numbers for those of you keen on statistics, most of the core running brands all had strong sales increases. Brooks and Mizuno improved about 40 %, Asics about 25 %, Saucony in the low teens and Nike in the high teens.  Under Armour running (not common here in Singapore) doubled for the year so far.

 To buck the trend, both Adidas and Reebok declined sharply in their share of running shoe sales.

Running For Your Life

I had this odd habit when I was a lot younger. I'll get something nice like a new watch, pen or shoe then I'll keep it somewhere safe. Then I will get the same thing (but not quite as nice) and use this instead of the "good" stuff that I got earlier. The thinking was that if I didn't use it, it'll last forever.

I guess I still have this habit sometimes and my wife will often ask me why I do that. Fortunately I didn't take the same approach with my body. I figured if I didn't use my body it'll definitely not last forever. Unlike machines, our bodies are made to move.

As with bicycles (or car, motocycle fill in your own), for the bike to perform their best you have to maintain it. While I was still racing triathlons, I spent lots of time cleaning, adjusting, lubricating and even polishing my bike. (For the difficult stuff, I'll get Kenneth or Yusoff from Cycleworx to help).

Now that I'm not racing and have a new born son, unlike a piece of mechanical equipment (which wears out the more you use it), I actually get stronger the more I exercise, now that I don't train like before. (Likewise I become a lot more unfit if I didn't).

Our bodies do share something similar with mechanical equipment. If you don't understand their limits, they can break down. If I run 3 times a week for half an hour and feel great and then decide that I will then run 6 times a week for an hour each time then I may be inviting an injury to come. (Trust me, I've had 3 knee operations remember). That's when I learned patience.

We live in an instantaneous society now and expect results overnight. Well, this is what I learnt, you don't become a great athlete overnight (and likewise you don't turn into a lousy athlete overnight or after a poor race). Our bodies can do almost anything we ask of it as long as we give it time to adjust to new demands.

The truth is when it comes to our bodies, we have to use it or lose it. If we don't, we'll find that one day when we want to go for a run and we can't as if we don't push ourselves, our bodies start to decline.

All right, I better get moving, not to run, but my son is starting to cry.

American Record By A "Fat" White Runner

This has been the most discussed topic for the past 2 weeks in most of the running forums I've read. American Chris Solinsky became the first white and heaviest runner so far, at 73 kg to dip under the 27 minutes barrier for 10000 m on the track.

By running 26:59 mins, Solinsky became the first non African born runner to break the 27:00 barrier, and on his debut race at 10000 m too.

Only 30 other men have run under 27 mins, and Solinsky is 9 kg heavier than the next heaviest.

Consider some of the following most illustrious runners on that list, Haile Gebrselassie at 1.65m and 56kg, Kenenisa Bekele (1.6m/ 54kg), Paul Tergat (1.82m/ 63kg) and Sammy Wanjiru (1.63m/52kg). Until Solinsky (who at 1.85m is the tallest), nobody heavier than 65 kg had run under 27 mins.

Many long distance running aficionados (myself included) were really surprised that someone this "big" could run so well. Most if not all other true elite long distance runners are never this tall nor this heavy. Solinsky is currently the tallest and heaviest (can we call him "fat") sub 27 min 10000 m runner. Prior to Solinsky, Paul Tergat (who on a good day can outrun Gebrselassie) is the next tallest at 1.82m but tip the scales at only 63 kg. Which makes Solinsky's achievement even more remarkable.

So, don't let anyone tell you that you that you are too big or fat or not fast enough. You can prove them (and their stereotypes) wrong. You have to work pretty hard though.

*Photo from letsrun.com