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Best time with artificial intelligence?
Race report about running training using Artificial Intelligence
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Why did I choose this half marathon in particular?
I signed up to the Händellauf Half Marathon primarily to run a half marathon with friends. The idea of setting a new personal best followed later. I asked myself whether this was even possible in Halle (Saale). The route was anything but flat, included some switchbacks, and, in addition, went through the Dölauer Heide, a woodland with unpaved, partly sandy ground – unfavorable conditions for a personal record. But my half marathon preparations were going well so I felt that a new personal best was likely in the cards.
CoachGPT had already helped me with training, nutrition, and equipment, so I also relied on the AI for the specific preparations. I was particularly interested in the pacing strategy, meaning how I should structure the route with reference to speed. ChatGPT recommended the “Negative Split Strategy”. In practice, this meant the following:


- Kilometers 1 to 5: controlled pace, about 5 seconds slower than the target speed (4:27-4:30 min/km).
- Kilometers 6 to 15: maintaining the target speed (4:22 min/km), adapting it to hills.
- Kilometers 16 to 21: if you feel up to it, increase the speed and use the flat or downhill sections for a sprint finish (4:15-4:18 min/km).
Intuitively, I would have started faster and corrected the pace later, if needed.
I also sought advice from the AI relating to nutrition in the days before the half marathon. The recommendations were not particularly surprising, but also somewhat inconsistent::
- Carbo-loading two to three days before the race (wholegrain pasta, rice, potatoes, quinoa, oats, bread, fruit)
- Ideally food that is easy to digest (but then, wholegrain pasta?)
- Plenty of fluids (2 to 3 liters per day)
- Pasta or rice on the eve of the competition, around 12 to 14 hours before the start
- A light breakfast high in carbohydrates 2 to 3 hours before the race
- 500 ml water 1 to 2 hours before the start
When it came to equipment, the AI believed that I shouldn’t try anything new. So I decided in favor of the Run Ultralight Mid Cut Socks, but against the Sports Achilles Support because I had not been training long with this product.



Day X – all or nothing
A truly turbulent start:
the night before the competition was, as usual, restless and ended too early. My alarm went off at 6 a.m. and at 9 a.m., I reported to receive my race number. At 10.50 a.m., I stood shivering in Halle’s market square with hundreds of other runners to wait for the starting signal that finally came at 11 a.m. The weather wasn’t ideal: it may have been dry and sunny at 12 degrees but there were strong gusts of wind reaching 70 km/h. The first 4 kilometers, I ran straight into a headwind without a group of others to protect me. The wind didn’t subside until I reached the first incline. And that was followed by uneven forest ground. I tried to control my speed and keep an eye on my heart rate. But I noticed from the beginning that I wasn’t having a good day. I simply couldn’t get into a good rhythm.


Nice landscape – but when is this forest section over?!
The route through the Dölauer Heide was attractive and may be ideal for a relaxed, long run, but on that day, it just seemed endless to me. The loose, partly sandy and slippery terrain zapped my energy. The many turns and slopes also interfered with my rhythm. I felt frustrated but when I came out of the woodland, I gathered new hope – sadly accompanied by strong headwind and more sandy ground.
A stitch – do I have to stop?
Despite the headwind, I felt positive because most of the uphill sections were behind me. The wind turned and thankfully started to follow me, but at the 12 kilometer mark, I felt a stitch in my right side. Stiches? I’ve never suffered from those! I tried to search my memory for a solution and thought of CoachGPT: breathe calmly into your stomach. I struggled for the next 2 kilometers and my pace dropped to 4:40/4:50. The next brief ascent and strong headwind reduced it further to 5:00.


Just make it to the finish line – but not like this!
I was convinced at this point: that was it! Beating my record was no longer possible. My mind switched from achieving to just making it through the race. I stumbled over a small ramp at kilometer 16.5. Just before that, I stopped at the drinks station to take a big gulp of cola. Someone overtook me at kilometer 20. I briefly tried to keep up but had to give up. When I made it to the finish line, I stopped my watch and was stunned: 1:33:40 – merely 7 seconds slower than my best! That couldn’t be right, could it? If I had known that it was so close, I would have made a final effort! If only, if only! A quick look at the overall time at some stage in between would have been enough.
A shocking end, but a huge learning outcome
It simply wasn’t my day, not the fastest (but a beautiful) route, less than ideal weather. But those were not the key reasons. I didn’t fight to the very end because I succumbed to negative thoughts and didn’t manage to recover properly after I hit the wall. Nonetheless, I’ve never learned a better lesson from any competition. That’s why the Händellauf Half Marathon was a win for me after all. I also have to learn to keep an eye on the intermediate times at specific kilometer stages.


5 more learnings and tips for (half)marathon training with AI 💪 after the race
- Don't forget to have fun during the race!
- The AI doesn't think of everything! It's better to ask too many questions than too few (splits).
- A good training plan doesn't automatically lead to a personal best.
- The AI also has encouraging words for you after a failed personal best attempt. If you ask it for them.
- The next training plan is just one request away.
Conclusion about preparing for and running a half marathon with AI support
Even though I didn’t achieve my goal, preparations with ChatGPT were a complete success. I was able to continuously improve my performance in the long term. The training plan provided me with a clear structure during all the half marathon preparations, without over-exerting myself. The AI also helped me with the immediate preparations for the competition. The question remains: will I continue to train using ChatGPT? My answer is: “Hi! Unfortunately, I wasn’t able to break my record. Can you create a new training plan for my half marathon in April?”