There’s an age-old debate about which is more difficult – running a marathon or running in a triathlon. Anyone who has ever competed in both would probably agree that they’re quite different experiences.

That’s primarily because when you compete in a marathon, you’re starting with a fresh pair of legs. During a triathlon, on the other hand, you’re going into your run after competing in the bike portion of the race. Depending on the event, this can be anywhere from 12.4 to 112 miles on the bike. And that’s after enduring a swim of .5 to 2.4 miles in length.

Marathon runners may be surprised to know that their competitive marathoner status does not necessarily set them up well for a smooth transition to become competitive triathletes. Statistics show that a majority of Ironman World Championship finishers have a stronger background in cycling than in competitive running.

If you run marathons and are considering trying out a triathlon, don’t expect to seamlessly become a triathlete without the right training. And don’t think for a minute that running will be the primary focus of your triathlon training. To really compete, you’ll have to spend more time training for the cycling leg of the event than for the run. This is not only because you have less experience cycling, but also because you’ll need to better prepare your legs for the run portion of the event.

For those thinking of transitioning from marathon running to triathlons, keep these training tips in mind:

Increase Your Bike Workouts

The more time you spend on the bike, the more likely you are to improve your run times during a triathlon event.

Focus On Cycling Form

To keep your legs as fresh as possible during your run, you’ll need to learn to rely on different muscle groups during your ride. Some experts recommend aero cycling because it engages your quadriceps more than your calves and hamstrings. This helps you save your leg strength for the run.

Follow A Race Day Bike:Run Ratio

During a triathlon, your cycle distance is about 4 times longer than your run distance. During training, you’ll want to follow a similar split of training time.

Increase The Volume Of Your Training

Preparing for a triathlon involves more training time than getting ready for a marathon. The good news for marathoners, however, is that triathlon training is usually not quite as intense as competitive marathon training (assuming you’re trying to beat a previous record). According to a small study conducted in Spain with experienced runners and triathletes, training load per hour for marathoners was significantly higher than it was for triathletes.

Know Your Running Form May Suffer

Many triathletes begin as cyclists, not runners. And since training time is split between biking, running and swimming, running form is often the first to suffer. Add to that the fact that even seasoned runners come into the start of their run after completing both the swimming and cycling segments of the race. That’s why running in a triathlon, especially an Ironman, is often referred to as shuffling. It’s not always pretty. Many athletes simply move their legs forward as best they can to reach the finish line without being able to focus much on form.

It’s unlikely debates between marathoners and triathletes over which event is harder, requires more training or challenges your body most will end any time soon. But any way you slice it, competing in a marathon or triathlon is quite a feat and one that is not for the faint of heart.