I have competed in international championships, I have experienced the pressure of an Olympic start, and I know what it means to go too fast at the beginning. In a marathon, pace is not important: it is decisive. Is it the most important thing? I would say it is what most influences the result. Even more than your current fitness level. You can be in peak physical condition, but if you mismanage the first 15 kilometres, you will pay the price at 35.

When I prepare for a marathon with the goal of beating my personal best, we're talking about an approximate finish time of 2:07:30, which implies an average pace of 3:01 min/km. But that number alone is not enough. I break the marathon down into different segments.:

● First 10 kilometres:30:20 minutes (pace of 3:02 min/km)

● Kilometre 10–21:33:25 minutes (pace of 3:02 min/km)

● Kilometre 21–30:27:00 minutes (pace of 3:01 min/km)

● Last 12 kilometres (km 30–42): 36:45 minutes maintain 3:01 min/km or progress towards 3:00 min/km if you feel up to it.

The HUAWEI WATCH GT Runner 2's race pace guidance system (officially called Marathon Guidance) turns that abstract goal into a dynamic and constant reference point. It's not just about seeing your instant pace: it's about receiving a real-time comparison between what you planned and what you did.

How to use Marathon Mode step by step:

1. In the exercise section, select HUAWEI’s new “Marathon” mode.

2. Choose the distance you are going to run, whether it is a 5, 10km run, "half marathon," "marathon," or a custom distance.

3. Select the time goal you want to achieve for the selected distance.

4. The watch guides you with its voice assistant to automatically calculate the necessary pace and determines during the run whether you are ahead of or behind the recommended plan.

When you compete with the world's elite, one second per kilometre ends up being a huge margin. That's why GPS accuracy is a basic necessity. The dual-band GPS on the HUAWEI WATCH GT Runner 2 provides essential accuracy in complex urban environments, partial tunnels or areas with tall buildings. I was quite surprised by the accuracy of the maps displayed by this smartwatch, and I could see the track where I train loaded on the map, even in Madrid's Casa de Campo, where you can lose signal, as it is a large park with big trees where I often go to train.

After each special training session, especially when it comes to a marathon preparation test such as a specific long run, I use the map afterwards to analyse:

● Curve tracings.

● Changes in pace associated with slopes.

● Micro variations in urban areas with buildings.

I train twice a day: sweat, rain, temperature changes, track sessions, gym. The watch has been through all of it with me. The first thing I value is something really simple: that it doesn't get in the way. At just 43.5g, the HUAWEI WATCH GT Runner 2 is the lightest metal smartwatch I know - and you feel it. It's stable, doesn't move even when the pace changes suddenly, and the AirDry band keeps comfort consistent even on runs of over two hours.

In a marathon, any distraction is amplified – and when you're at kilometre 37, every little detail adds to your mental fatigue. The battery is another critical factor. My training weeks include long sessions with active GPS, constant heart rate measurement and post-session analysis. I can't be charging my watch every day like a phone. According to the manufacturer, the HUAWEI WATCH GT Runner 2 offers up to 14 days of battery life and 32 hours of continuous GPS tracking.