Running

Half Marathon Training Plan by AI

Will you achieve a new half marathon personal best with CoachGPT?

AI instead of a coach — does it work?

My plan was to improve my best half marathon time – not by myself but with the help of a virtual training partner: ChatGPT. The idea was to do away with the usual advice and established half marathon training plans and find out what AI can do. I wanted ChatGPT to take the lead and develop a half marathon training plan tailored specifically to me. Find out in my report why the first attempt failed, why the second try was better, and how you can benefit from an AI training plan.

A runner on a wet track at sunrise. The sky is cloudy, but the sun is breaking through as the runner completes his lap.

Why a half marathon?

In the summer of 2024, I desperately needed a sporting goal to keep my motivation going until the winter break. I was happy to try anything from juggling 5 balls and CrossFit to steeplechase. But then several of my friends signed up to do a half marathon and it sparked my interest. I set my previous record of 1:33:33 as part of my preparation for a Half Ironman – that was in 2017. Since then, I haven’t just got older but my life has also changed in many ways. In addition to two children, Artificial Intelligence has also become part of my life. I don’t have a running trainer but I use AI tools professionally and privately nearly every day. So I had the idea for the AI to create a half marathon training plan for me.

Creating a half marathon training plan with ChatGPT

There are several good reasons for creating a half marathon training plan with ChatGPT. The basic version of the AI program is free, so that means the training plan doesn’t cost anything. Plus, the program is very user-friendly. You enter a question in the chat window and the answer appears immediately. However, I needed several attempts until a viable half marathon plan was produced for me. From the first input “Please create a training plan so I can run a half marathon in under 1:30” to:

A trail runner running on a rocky path through a dense forest. The surroundings are green and peaceful, perfect for intense outdoor training.

“Hi! Can you please develop an ideal and efficient training plan for my half marathon on October 13, 2024? The objective of my training plan is to improve my current best of 1:33:33, ideally to 1:29:59. For family reasons, I can only train three to four days per week. I enjoy cycling so you can include training on a racing bike. I can easily integrate strength training in my daily life so you can add leg and core workouts if that’s beneficial. Some information about me: I’m 39 and I weigh 78 kg at a height of 1.81 m. The training plan should have specific guidelines relating to speed for the individual running sessions, it should feature variety, and not include unnecessary mileage. I’d also like very specific exercises and parameters for the cycling and strength sessions. The plan should be clear and have a specific date for each week, ending in the week of the competition.”

Close-up of a runner breathing heavily after a run. He is wearing a blue singlet and a cap, looking into the camera.

it took an hour. Small adjustments in the prompt resulted in major differences in the half marathon training plan.

The training structure was free of charge but required a bit of time to set up. At first glance, I got a training plan with variety that met all my requirements. But looking more closely, I noticed some problems. For example, both high and fast demands were made, such as an endurance run of 20 km at a pace of 4:55. There were also no recovery weeks. Most training plans are based on the “progressive overload” principle, i.e. three increasingly intensive weeks are followed by a quieter week. Still, I was very motivated when I started the AI training plan experiment.

Complete overhaul – Plan A aborted for a new training plan after four weeks

A runner jogging on a rural field path under a slightly cloudy sky. The surroundings are calm and vast, perfect for endurance training.

I quickly realized that I wouldn’t be able to keep up with the set task. After an extremely challenging session where I was meant to run 12 km at a pace of 4:20, I was close to giving up my AI training plan altogether after four weeks. Almost every session was torture and I constantly reached my limit even though I always used the fastest running socks I knew. Then, I decided to try something else: instead of coming up with the perfect prompt, I had the idea of creating the training plan together with ChatGPT, similar to a real coach. I typed the following:

“Hi! Can we create a training plan for a half marathon together? Ask me what you need to know!”

I then received a comprehensive list of questions that I answered in detail. After that, I got the draft of the new training plan with the question whether the rough concept was suitable for me. As a matter of fact, there was nothing wrong with it. This provided me with a new training plan leading up to Day X, which was much more realistic and frightened me a lot less. It even included tapering (reduction of the training volume) in the last two weeks before the competition. The new half marathon training plan suggested by ChatGPT consisted of three key elements: long runs, fast runs at a half marathon pace, and quick, extensive intervals at a slower pace than would happen during the half marathon. These sessions were designed to improve energy metabolism, getting used to the running speed, and oxygen intake.

Close-up of a runner’s shoes on the red track, ready for training. The scene symbolizes determination and athletic focus.

Week	Day	Session
Week 1	Tuesday	Interval training: 6x1 km at 4:15 min/km, running ABC
Week 1	Wednesday	Cycling session: 90 minutes, moderate intensity
Week 1	Friday	Speed/technique run: 5 km at half marathon speed, accelerating runs
Week 1	Sunday	Long-distance run: 90 minutes, casual pace
Week 1	Thursday	Strength training: 30 minutes (optional)
Week 2	Tuesday	Interval training: 7x1 km at 4:10 min/km, running ABC
Week 2	Wednesday	Cycling session: 90 minutes, moderate intensity
Week 2	Friday	Speed/technique run: 6 km at half marathon speed, accelerating runs
Week 2	Sunday	Long-distance run: 100 minutes, casual pace
Week 2	Thursday	Strength training: 30 minutes (optional)
Week 3	Tuesday	Interval training: 8x1 km at 4:08 min/km, running ABC
Week 3	Wednesday	Cycling session: 90 minutes, moderate intensity
Week 3	Friday	Speed/technique run: 7 km at half marathon speed, accelerating runs
Week 3	Sunday	Long-distance run: 110 minutes, casual pace
Week 3	Thursday	Strength training: 30 minutes (optional)
Week 4	Tuesday	Interval training: 5x1.5 km at 4:10 min/km, running ABC
Week 4	Wednesday	Cycling session: 90 minutes, moderate intensity
Week 4	Friday	Speed/technique run: 8 km at half marathon speed, accelerating runs
Week 4	Sunday	Long-distance run: 120 minutes, casual pace
Week 4	Thursday	Strength training: 30 minutes (optional)

Week	Day	Session
Week 5	Tuesday	Interval training: 6x1.5 km at 4:08 min/km, running ABC
Week 5	Wednesday	Cycling session: 90 minutes, moderate intensity
Week 5	Friday	Speed/technique run: 9 km at half marathon speed, accelerating runs
Week 5	Sunday	Long-distance run: 120 minutes, casual pace
Week 5	Thursday	Strength training: 30 minutes (optional)
Week 6	Tuesday	Interval training: 5x2 km at 4:05 min/km, running ABC
Week 6	Wednesday	Cycling session: 90 minutes, moderate intensity
Week 6	Friday	Speed/technique run: 10 km at half marathon speed, accelerating runs
Week 6	Sunday	Long-distance run: 120 minutes, casual pace
Week 6	Thursday	Strength training: 30 minutes (optional)
Week 7	Tuesday	Interval training: 4x2 km at 4:00 min/km, running ABC
Week 7	Wednesday	Cycling session: 75 minutes, moderate intensity
Week 7	Friday	Speed/technique run: 8 km at half marathon speed, accelerating runs
Week 7	Sunday	Long-distance run: 90 minutes, casual pace
Week 7	Thursday	Strength training: 30 minutes (optional)
Week 8	Tuesday	Interval training: 4x1 km at 4:00 min/km, running ABC
Week 8	Wednesday	Easy cycling session: 60 minutes, casual pace
Week 8	Friday	Short speed/technique run: 4 km at half marathon speed, accelerating runs
Week 8	Sunday	Half marathon competition

A bowl of chickpea salad surrounded by fresh ingredients like avocado, lemon, and bread. Ideal for a healthy and nutritious meal post-training.

During the following days and weeks, I asked the AI further questions about nutrition, stretching, equipment, and even the ideal running technique – basically anything I would have asked an actual coach. In all those areas, ChatGPT managed to help me. I bought two new pairs of running shoes, made recovery a priority, and consumed more carbohydrates and protein, so I would have sufficient energy for the speed runs. In addition, I did some stretches two to three times a week, regularly used a fascia roller, and wore Sports Recovery Socks after each session.

The new program may have felt demanding, but week after week, I noticed significant progress. The short intervals of one to two kilometers in particular, which I completed at the track, became a real highlight. While I struggled to reach targets of 4:10 to 4:00 during the first three weeks, my times practically exploded from Week 4. The runs remained challenging but I regularly experienced the amazing feeling of runner’s high. Only the long runs from 90 to 120 minutes at a casual speed were pretty tough at times. Plus, during extended periods of exertion – much like during the Race around the Netherlands – my Achilles tendon kept hurting. But using the Sports Achilles Support, I managed to counteract this problem because I needed these runs to get the mileage under my belt and have a different stimulus for my training. I was able to complete 85% of the set tasks from my training plan. The rest fell victim to my limited spare time. The most important thing for me was that the running training was actually very good fun and made me faster at the same time!

The shadow of a runner on a red track showing the victory sign with their hand. The scene symbolizes success and achievement in running training.

A runner in a blue singlet running on a paved path in nature. The path is lined with trees and a red-white barrier.

5 lessons learned and tips for (half) marathon training using AI 💪

Training plans using AI are not carved in stone but a suggestion you have to check.
Listen to your body! If the training plan doesn’t feel right, it’s not suitable for you.
Training successfully is more than just going through the motions during the sessions. Equipment, nutrition, and sleep also play a key role. AI can provide support here, too.
Work together and interact with the AI instead of just entering instructions.
You don’t have to slavishly follow the training plan to make progress. Just get CoachGPT to adjust the plan for you as and when necessary.

A runner sits and tightens the laces of his black running shoes while wearing blue compression socks. He is preparing for an intense training session.

A long, straight gravel path stretching through a vast landscape with clear skies and fields on both sides. Ideal running route for endurance runs.

My conclusion about half marathon training using Artificial Intelligence

Even though I failed with the first training plan provided by ChatGPT, I was able to significantly improve my performance using the second plan. My runs regularly got faster and felt better and better. I may not have managed to complete every training session 100%, but I felt perfectly prepared at the end. The AI was also able to help me in many other areas of my running training. I can recommend a training plan suggested by ChatGPT to anyone who is not at the very beginning or at the extreme peak of their performance. Based on my experience, I believe that AI is less suitable for beginners without structured training or for highly ambitious athletes who want to find that last percent to improve. But for all others, it’s a beneficial training partner.