Triathlon for Runners: How to Adapt Your Training for Multisport Success

So, you're a runner. You've mastered the art of pounding the pavement, logging miles, and maybe even setting personal bests at various distances. But now, you're eyeing the triathlon—a multisport beast that brings together swimming, cycling, and running. And while the running leg may be your comfort zone, let’s face it: the other two legs might as well be a foreign language. But fear not! Transitioning from pure running to triathlon success is more than doable. With a few smart adjustments to your training, you’ll be on your way to mastering all three disciplines. Ready to trade your running shoes for some goggles and a bike helmet? Let’s dive in.

The Runner's Strengths and Weaknesses in Triathlon

First things first: let’s take stock of what you, as a runner, bring to the table in triathlon. Running is often the final leg in a triathlon, and being a seasoned runner gives you a strong advantage here. By the time most triathletes hit the run, their legs are tired, and they’re hanging on for dear life. You? You’re just getting started. You’ve already got the mental fortitude and muscle endurance to finish strong.

But, and this is a big but, running is only one-third of the race. Swimming and cycling engage different muscle groups, require varied cardiovascular demands, and—sorry to break it to you—come with their own set of challenges. Running fitness doesn’t always translate smoothly into swim or bike performance, and that’s where adaptation comes in.

Step One: Learn to Swim Without Drowning

For many runners, swimming is the most daunting part of the triathlon. You’re used to gravity keeping you grounded, but suddenly you’re in a medium where your usual forward motion has transformed into something akin to dog paddling for dear life. Let’s fix that.

1. Focus on Technique, Not Power

Unlike running, where pure endurance can take you far, swimming is about efficiency. You can’t power through the water in the same way you can through a marathon wall. Instead, you need to make every stroke count. Think of swimming as a technical skill—mastering it takes time, but the rewards are significant.

• Breathing: Breathing every other stroke is great in theory, but in reality, you might feel like you’re drowning at first. Practice bilateral breathing (alternating sides) to help balance your stroke and reduce fatigue.

• Form: Hire a swim coach or take a few lessons if needed. Correcting poor form early on will save you hours of frustration in the pool. If you swim like a thrashing octopus, you'll tire yourself out long before T1 (the first transition).

2. Swim Often, Swim Shorter

The biggest mistake runners make when switching to triathlon training is treating swimming like running—going long and hard every session. Swimming, especially at the beginning, should be about frequency and form rather than distance. Swim three to four times a week, focusing on technique and gradually increasing your distance. Keep the sessions shorter but more consistent. In swimming, progress comes in millimeters, not miles.

• Intervals: Incorporate interval training in the pool just as you would with running. Mix in sets of 50 or 100 meters with brief rest periods. This will help improve both your speed and endurance in the water without burning you out.

Step Two: Get to Know Your Bike (Really Well)

Next up: cycling. If swimming is the most technically challenging, cycling is the most gear-dependent. Welcome to the world of carbon frames, clip-in shoes, aero bars, and more Lycra than you ever thought you’d own. Don’t worry, though. Once you get past the initial “what does this button do?” phase, cycling can be one of the most enjoyable parts of triathlon training.

1. Invest in the Right Bike—But Don't Go Overboard

There’s no denying that a triathlon bike is a major investment. If you’re just starting out, don’t feel like you need to remortgage your house for the lightest, sleekest, most aero setup. A decent road bike with clip-on aero bars can be enough for your first few races. The goal is to get comfortable on two wheels and gradually build up your bike-specific fitness.

2. Find Your Cadence Sweet Spot

Unlike running, where you can settle into a pace that feels comfortable, cycling requires finding a cadence—typically around 85-100 RPM (revolutions per minute)—that allows you to maximize power output while conserving energy. Aim for a cadence that feels smooth and sustainable for longer efforts. If you’re used to cranking out low-cadence, high-resistance bike workouts at the gym, it’s time to shift gears—literally and metaphorically.

3. Incorporate Long Rides (But Start Small)

While runners are used to going long, cycling distances in a triathlon are a whole new ball game. A half-marathon might seem easy compared to a 56-mile bike ride (hello, Ironman 70.3), but don’t be intimidated. Start small with your cycling distances and build gradually. Add a long ride once a week, just as you would with long runs in marathon training.

• Brick Workouts: Practice bike-run transitions with brick workouts—where you hop off the bike and immediately start running. These sessions will teach your legs to handle the strange feeling of switching from cycling to running (spoiler: it feels like you’re running in molasses at first).

Step Three: Don't Forget Strength and Flexibility

Runners tend to have an unfortunate blind spot when it comes to strength training and flexibility work. If your idea of "strength training" involves carrying groceries in one trip, it’s time for a shift in perspective. Triathlon requires more than just cardio fitness—it demands strength, especially in your core, glutes, and hips.

1. Add Functional Strength Work

Swimming requires upper body strength, cycling demands leg power, and running calls for total-body endurance. To train for triathlon, you need a blend of strength and flexibility. Incorporate functional strength exercises, like squats, lunges, planks, and deadlifts, into your weekly routine. A strong core will improve your balance in the water, your posture on the bike, and your endurance during the run.

2. Stretch, Stretch, Stretch

Flexibility often takes a back seat in running training, but it’s critical for triathlon success. The repetitive motions of swimming, cycling, and running can lead to tight muscles and imbalances if you're not careful. Incorporate a flexibility routine that focuses on your shoulders, hamstrings, calves, and hip flexors—areas that tend to get tight during training.

• Yoga: Consider adding a weekly yoga session to help with flexibility, balance, and mental focus. It’s not only great for recovery but will also improve your range of motion in all three sports.

Step Four: Training for Balance

The biggest adjustment for runners transitioning to triathlon is finding the balance between three sports instead of one. Gone are the days of stacking five or six run days a week. Now, you’ll need to distribute your training across swimming, cycling, and running—without burning out.

1. Create a Weekly Plan

Plan your week so that you balance your three sports while allowing for adequate recovery. A good starting point might look like this:

• Swim: 3-4 sessions per week, focusing on technique and endurance.

• Bike: 2-3 rides per week, including one long ride and one interval session.

• Run: 2-3 runs per week, including one long run and a tempo or speed session.

• Brick Workout: 1-2 times per week, combining cycling and running to simulate race day transitions.

2. Listen to Your Body

Triathlon training can be demanding, especially as you build endurance across multiple disciplines. It’s important to listen to your body and prioritize recovery when needed. Pay attention to any signs of overtraining—fatigue, irritability, or persistent soreness—and adjust your workouts accordingly. It’s better to ease up for a few days than to risk injury.

Final Thoughts: Embrace the Multisport Life

Transitioning from a runner to a triathlete is a rewarding journey that will challenge you in new and exciting ways. By adapting your training to include swimming and cycling while maintaining your running base, you’ll be well on your way to multisport success. Keep a balanced approach, focus on technique, and enjoy the ride—literally. After all, you’re not just running anymore; you’re swimming, biking, and running your way to the finish line.