Eilish McColgan is preparing for a major transition in her career—her first marathon. With an incredible pedigree on the roads already, holding the British Half Marathon Record, and the European 10K record. Eilish is now applying a data-driven approach to tackling 26.2 miles in London this April.

2024: The Road Back to the Fitness

After knee surgery late on in 2023, EIilish faced a long road to building back fitness in 2024. She successfully qualified for her fourth Olympic Games, and closed out the season winning both the Big Half and London 10k and narrowly missing a podium at the Great North Run.

"It feels good to be back feeling strong coming off the longest injury I've had. I ticked some important boxes last year and finished with some results I was really proud of. In 2025, I want to get back to where I was, ready to start this next chapter of my career on the roads"

2025: The Road to London

Eilish has slowly been transitioning from the track to the roads over the past few seasons, targeting the 10K and Half Marathon distances. Now looking to take on the full distance, there was no place more fitting place than London.

"I've always enjoyed racing in London, it was where I ran in my first Olympic Games, and I've had such incredible support whenever I've raced through the streets. Experiencing this on London Marathon day with the crowd and the atmosphere will be something special."

Building Base Fitness

Eilish has been steadily increasing her training and Base Fitness since returning from her break. Having conquered the half-marathon distance, Eilish is used to training hard, but doubling the distance requires taking things up a bit. A vital metric for her during marathon training is Training Load to ensure she is right on track and not overdoing the training.

"I know my body can handle the training required for a marathon. Over the years, I've learned what works well for me and so I'm very intune with how I'm feeling. Being able to view metrics like Training Load, from a single session or for the past few weeks fills me with confidence that things are heading in the right direction and I am building the resilience I need for the marathon."

COROS Education: Training Load measures the impact brought to your body from the training using your heart rate data and workout duration.

Sustained Efforts: Introducing Marathon Pace

One of the essential components to marathon training are the long runs, although fatiguing on the body, these efforts prep the body and mind for race day. Inbetween travelling, Eilish opted for the treadmill to complete a continuous 8-mile effort at working down to 3:14/km right in the middle of her Tempo Pace Zone.

"I don't have a goal time in mind, so I'm sort of trying to feel my way into marathon effort at the moment. The treadmill is great for this, and having the COROS Extender showing the live heart rate helps me to internalise that effort."

Treadmill Intervals: Controlling the Effort

Interval training has been a regular component of Eilish's training over the year's, but in the build up to London, the volume and intensity is stepping up. Completing 20 x 800m again taking to the treadmill for the workout.

"This was a great simulator for race day, intervals replicate the surges that you get from racing, especially as people jostle for position at the fueling stations."

COROS Education: You can set up a Basic Interval workout when starting a Run, Indoor Run or Track Run Activity on your COROS watch. Choosing the amount and duration of repetitions, adding the appropriate amount of warm up, warm down and rest between efforts.

The Final Stretch: Precision Tapering and Race Strategy

With London approaching, this will be EIlish's biggest test to date, but with rigorous preparation and an analytical approach, she aims not just to complete the 26.2 miles—but to compete at the highest level.

"There is still a lot of work to do from now until April and I have some hard weeks ahead in Colorado, but I know what needs to be done from now until race day and seeing the progress in the numbers keeps filling me with confidence and excitement to get going."

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