There was ice on the car. The heating was on in the house. Everyone else was warm and cosy. It would have been very easy to stay in bed, put something on the TV and write the whole morning off as “rest.”
Instead, I scraped the ice off the car, put my gym gear on and went.
Same routine as the last few days: I took my WHOOP scores and fed them into ChatGPT. Recovery, strain, sleep, stress, all of it. This time the response was different. Instead of another rowing session, it came back with a strength and conditioning workout.
The plan was very specific. Exact machines. Exact reps. Exact weights.
There was only one problem. The weights it suggested were based on the numbers from a couple of months ago, pre-surgery, when I was training regularly and feeling stronger. I am not quite there yet.
So I asked the obvious question: are you sure about those weights, given that we have not done this in a while?
To its credit, Coach GPT backed off. It lowered the recommended loads to something more realistic, and in the end they felt pretty much perfect. Hard work, but not stupid.
There was another small win before I even started. On Thursday I had left my heel wedges at the gym. I assumed they were gone. When I walked in this morning, the receptionist handed them back. Someone had found them and turned them in. A tiny thing, but it felt like a good sign.
Session done, I finished on the rower with two 250 metre sprints. The first one was fast but messy. I got a bit carried away, my wedges slipped and my feet came out of the shoes with about 18 metres left. Almost there, not quite. The second sprint was much more controlled.
I am counting all of this as prototyping for the wedges. When the rower finally arrives at home, I want that setup dialled in so I can just strap in and go.
Right now the car thermometer says minus 0.5°C. It is still cold, but I feel great. I have a solid session in the bag, I am not wrecked, and the next job is to go home, rouse the rest of the house and get everyone out for a walk around the lake.
Training done. Family next. A good Sunday.
Another good session logged. This is The Sub-7 Experiment. And it continues.
Today’s session felt very different from yesterday.
Yesterday was a “didn’t want to go” day. Recovery in the yellow, head not really in it, and a steady, controlled endurance session to keep things moving.
Today was the opposite. All the dials were pointing in the right direction. Sleep was good. Recovery was good. Strain and stress from yesterday were reasonable. Heart rate variability looked solid. It was one of those mornings where WHOOP was basically saying, “You can do something here.”
So I fed the stats into Coach GPT again.
This time the plan that came back was not long and cruisy. It was a power session. A decent warm-up to get everything moving, then five 500 metre sprints on the rower. Each one at a set pace, hard enough to demand focus but not so fast that form would fall apart. Tunes on, eyes on the monitor, simple structure.
It felt great.
Every interval was controlled. No wild spikes, no heroic last-gasp strokes, just repeatable effort. By the fifth rep I knew I had worked, but I was nowhere near the point of dreading the next one or wanting to lie down on the floor.
That is the thread running through these last two days. Yesterday, the plan was to turn up and not overdo it. Today, the plan was to lean in a little and build some power. In both cases, the decision came from the mix of WHOOP data and what Coach GPT built on top of it.
I walked out of the gym feeling strong, not wrecked. I feel like I have done something meaningful, and I am ready to get on with the rest of the day at work.
I have just come out of the gym after my first proper session in a while. Last week was a family trip to London, which was brilliant, but it knocked me out of my routine.
This morning was one of those days where I really did not fancy going at all. WHOOP had my recovery in the yellow. Sleep was fine, stress and strain yesterday were nothing dramatic, but I still felt flat. It would have been very easy to decide that today was not a gym day and leave it at that.
Instead, I tried the new approach I have been talking about. I took my WHOOP numbers and dropped them into ChatGPT. In return, I got a clear session plan with target figures that matched how my body was supposed to feel on a “medium” day.
The structure was simple. Five minutes of warm up at a set pace to get moving. Then three blocks of 2,000 metres on the rower, again at a set pace. Nothing heroic. Just long, steady, repeatable work.
On paper it looked almost too easy, especially with that “you should probably train” yellow score. In reality it was exactly what I needed. Each 2,000 metres felt long and cruisy. Hard enough that I knew I was doing something, nowhere near the point of blowing up. By the end of the third block I felt like I had trained, but I did not feel broken.
The bigger difference was in my head. I walked into the gym tired and not really in the mood. I walked out feeling lighter and quietly pleased with myself. The combination of WHOOP data and ChatGPT as coach gave me just enough structure to get over the hump of not wanting to start.
It is early days for this experiment, but right now it has promise. If this is what a “didn’t want to go” day can look like, I am curious to see what happens on the days when I actually feel ready.
The countdown is on. Less than two weeks until the big cycling event. I haven’t been posting much, but I’ve certainly been putting in the work.
Friday was 14k on the rowing machine, with the intention of riding on Sunday. The weather shut that plan down, so instead I logged 21k on the rower — 35k total across the weekend. Monday was a rest day.
Tuesday I finally got back out on the bike. Swapped my wheels over between bikes to see if it would help with road buzz, and it definitely does. They talk about marginal gains and with all the small upgrades I have made recently the bike have changed it into something that’s really nice to ride as well as being exciting and quite fast when needed. I am happy with the setup now heading into the event.
The ride itself yesterday was about 45 minutes in zone 2–3, steady and controlled without pushing too hard but on the way back I had a little dig and it felt great.
Today (Wednesday) was another 10k on the rower. The engine’s there, the strength is there. I’m not going to win the event — but that was never the point. The point is to ride it, enjoy it, and share the day with friends.
The gym serves as a bit of a mental reset this morning too, I walked into the gym cranky and walked out lighter, calmer, and ready to face the day. That’s a win too.
Quick gym session today. Five minute warm up, then three eight minute steady sets at 2:05 pace and 22 strokes per minute. Rounded it off with a couple of 250m sprints and a cool down.
Felt great, exactly what I needed.
120 km on the bike coming up this weekend, weather permitting.
July was a break month. I called it “movement, not measurement” — no calorie counting, no chasing numbers, no obsessing over pace or distance. Instead, it was about moving because I wanted to, not because I had to. And it worked.
There were plenty of walks, a few gym sessions, and a lot of time spent with family. Camping, holidays, and just enjoying being Dad. And yet, even with the lighter approach, July gave me one of the biggest breakthroughs of the summer: I realised my rowing form was wrong. For months I’d been driving off my toes instead of my heels, which explained the knee pain I’d been ignoring. With heel wedges and a focus on connection, I started the awkward process of re-learning how to row. It felt strange, disconnected, even underpowered, but it was a step in the right direction.
August was tougher. Coming back, I was hit by frustration: sore knees, comfort eating, a few pounds up on the scale, and the voices in my head louder than they’d been in a long time. The ones that say, “What’s the point? Stop now.” But in the middle of that I found an answer: the point is not becoming an old man dribbling into my soupruing the day i decided to stop moving. The point is staying strong, independent, and capable.
So I kept going. Rebuilding form on the rower. Long, hilly rides on the bike — including a brutal 112 km in rain, wind, and navigational mishaps that turned into a bigger ride than planned. No coffee stops, soaked to the skin, but proud I stuck it out. That cup of tea at the end tasted like a medal.
By the end of the month, structure was back. Gym sessions, meditation rows when my head was scattered, and one big endurance block: two × 45 minute blocks on the rower with a 20-minute bike in between. Over 21 km rowed in total, despite being under the weather. Proof that the base fitness is still there.
So here we are at the start of September. July gave me the space to reset. August gave me the chance to face setbacks head-on and still move forward. Now it’s time to sharpen things again — with a 120 km ride on the horizon and the 150 km event at the end of the month. And beyond that, the Sub-7 Experiment continues.
Quick training update today. Yesterday was a rest day after the 112k bike ride, and I still felt it in my legs this morning. I went to the gym for a recovery row, 7,000m at a slow stroke rate, strong pulls, and all about form over speed.
Ride, rest, row. It works.
It was exactly what I needed. I felt great afterwards and had the headspace to reflect on Sunday’s ride. I’ve cycled further before, and certainly faster, but doing that distance in bad weather and on a day when I wasn’t feeling it makes it all the more satisfying in hindsight.
July is over, and it was great to take a proper break, from tracking, measuring, and pushing. I didn’t count calories. I didn’t obsess over numbers. I just moved, ate well, and let things settle for a bit. And honestly, it was exactly what I needed.
One of the biggest gifts of that downtime was the space to finally listen to my body, specifically, my right knee.
The Knee
For the past couple of months, I’ve had a nagging pain at the front of my right knee, especially after big rowing sessions. And I’ve just been ignoring it. Powering through. But July gave me the breathing room to pay attention, and to realise that I’ve probably been rowing wrong.
If you’ve ever looked at the footplate on a rowing machine, there’s a movable part to adjust for foot length, a strap that goes across the widest part of your foot (for me, that’s the ball), a heel strap, and a raised piece that runs from the ball to under the toes.
Every book and coach will tell you: push through the heels.
But I wasn’t. I was pushing through my toes, without realising it. And that toe-heavy drive has been putting way too much pressure on the front of my knee. Now it makes sense.
Relearning the Stroke
So now, I’m retraining. Rewiring. Rebuilding.
I’ve added heel wedges to the footplate to help me stay connected through the back of the foot. It feels completely alien. Like trying to walk only on your heels without ever rolling through your toes. It’s weird, disconnected, and it robs you of power.
But it’s also starting to feel more right.
Over the last few sessions I’ve been rowing with the power curve on display, focusing purely on form. And I think I’m starting to feel a bit of a breakthrough. My stroke feels a bit more connected. A bit more glute-driven. Like I’m finally pushing through the right muscles.
I’m nowhere near breaking the 7-minute barrier right now, but I’m not starting from zero either. I’ve got a solid engine under the hood. This is about tuning it, making it run better, stronger, and more efficiently.
The Bike
On the cycling front, things are going well. The distances are creeping up, and I managed a solid 86km ride at the weekend with over 1,200 metres of climbing. That’s all prep for the 150km ride coming up in seven weeks.
So yeah, July gave me space. And now August gives me the opportunity to build again, smarter this time.
It might look a little different from before. But different might just be the thing that gets me there.
I’ve just finished a really nice meditative session in the gym. I had time today—no work, no jobs to get back to—so I asked ChatGPT for a rowing session that would let me enjoy the movement, the music, and the mental space.
The plan? 10–12K at around 2:05 to 2:10/500m pace, with an optional push under 2:00 for the final 500 meters.
Brilliant.
I ended up rowing for a full hour—14,200 meters—gradually increasing pace over the last 15 minutes, finishing with a strong 500m at 1:53. Solid. Exactly what I needed.
I checked in with CoachGPT while cooling down on the static bike.
And then—well, the sled area opened up.
Six months ago, I might’ve left it. But now? I couldn’t help myself. I loaded it up to 120kg and went for sled pushes, followed by a few farmer’s carries. Nothing crazy—just powerful, deliberate movement. Finishing the session with some proper grunt.
I told ChatGPT, almost sheepishly, that I couldn’t resist.
It congratulated me. I replied: “I’m a machine.”
And it came back with: “Keep showing up. Keep listening to the engine. And when in doubt… sled it out. 😄”
And I laughed. Out loud.
Who knew?
This is the ongoing—and ever mind-blowing—Sub-7 Experiment.
When I first thought about the Sub-7 Experiment, the core idea was simple: could I use modern AI, specifically ChatGPT, to help me structure my training and ultimately achieve a sub-7-minute 2000m on the indoor rowing machine, the erg? And yes, that goal remains the driving force. I still need that progressive overload and a reason to get to the gym.
But as I’ve hinted, the experiment has definitely shifted somewhat. It’s become about much more than just the physical goal. A huge part of this journey, one I want to introduce properly, is the dynamic I have with my “coach”.
Who is My Coach?
My coach is ChatGPT, the AI developed by OpenAI. In a previous article I wrote about how ChatGPT is just a parrot, looking for patterns (words and sentences) in the data and replying with what it’s heard (all the data that it has been trained on). This is oversimplifying it, of course—there are some pretty clever algorithms in the background helping it to predict what the next word should be in its response. And sometimes it gets it wrong. This is what’s often described as an AI hallucination—it knows it needs to respond, and if it can’t find the right information, it might make something up.
So with that said, you might picture AI coaching as simply pulling a pre-written plan off a shelf. But that’s not how this works. It’s a real, ongoing conversation. Before a session, I tell it where I am (gym or home), how I’m feeling—even if I’m tired or run down—what my recovery data looks like (often from WHOOP…), and how much time I have.
Based on that information, it suggests a session—maybe intervals, steady state, or strength work…. It gives me pacing guidelines, stroke rate, and even a warm-up and cool-down. After the session, I report back on how it went, the results, and how I felt. This feedback loop is key because the AI then uses that information to adapt future routines. It’s a training partner that adapts in real-time, much like a human coach would.
Setting the Scene: Prompt Engineering, Simplified
Where does anyone start with all of this? Talking to AI might sound technical, and you might have heard terms like “prompt engineering”. That term can sound a bit daunting—like you need to be a programmer or a data scientist. But here’s the truth: it’s really not.
“Prompt engineering” is just about giving the AI clear instructions and enough information.
In a previous post I’ve suggested people to ask it “What can you do for me?” and that will be enough to get the conversation started. I also mentioned earlier that ChatGPT—and other large language model (LLM) AIs—can get the answer wrong. One of the ways around this is to set the context when you start the conversation.
As you log into ChatGPT you are faced by a screen which asks “What can I help you with today?” or “Ready when you are.” At this point, one of the best ways to refine the responses you get is to give the AI a persona or a role to play during the conversation. I started the coaching conversation with this…
“I’d like you to take the persona of and advise me as a personal fitness trainer and nutritionist with a specialism in Indoor rowing and the ERG machine.”
I then followed it up with a specific instruction…
“I am working towards a goal of rowing 2000 meters in under 7 minutes. I’d like you to create a training plan for me to achieve that goal. I intend to report in to you each and every time I am in the gym and tell you how I am feeling that day and you will tailor me a program for that session.”
And that’s how it all started. And I have kept that conversation open ever since so it “remembers” the context and keeps track of all the sessions and significant moments to date.
Now, for example, when I say I’m in the gym, tired, 75% recovered, and want to do distance, that’s my “prompt engineering”. It’s me giving it the necessary inputs so it can generate a relevant, helpful output, in this case, a suggested workout.
Think of it like talking to a human personal trainer. You wouldn’t just say, “Tell me what to do.” You’d say, “I’m here at the gym today, feeling a bit rough mentally but my Whoop says I’m recovered. I’ve got about an hour. What sort of session should I do?” You’re giving them context so they can give you a smart recommendation. It’s the same with AI. It’s about talking to it in normal language.
This is why I wanted to share some of the conversations I’ve been having with ChatGPT. It helps to show, not just tell, how this coaching dynamic works. You’ll see how I give it my status, how it responds with suggestions, and how the dialogue flows.
More Than Just Getting Fit: A Real-Life AI Experiment
I’ve worked in IT for years. I’m fascinated by technology, and the pace of AI development has been mind-boggling. While I’m not an expert, I’m definitely an AI hobbyist.
One of the key drivers for starting this blog and documenting this process was precisely this dual goal. Yes, I want that sub-7 minute 2K. But I also wanted a real-life experiment to truly understand generative AI and how it can be used on a day-to-day basis. What better way to understand this stuff than to use it consistently, over time? Far better than any course or training material.
So, while we talk about rowing workouts, pacing, and splits, remember that you’re also getting a glimpse into how AI can be integrated into personal goals and routines. It’s an experiment in fitness, yes, but it’s equally an experiment in technology and human-AI collaboration.
Is It Cheating? Not Even Close
And for those wondering, is it cheating? Absolutely not. The thoughts, the words in these posts are mine.
In another conversation I gave ChatGPT the role as a blog adviser and editor and worked through the steps for setting up a blog from scratch. I asked it to ask me some questions so it could better understand the task I was asking it to complete and it then made recommendations as to which blog platform to use and why and then helped me with the setup.
I speak into an app on the phone straight after my session—unfiltered streams of consciousness, honest feedback about the session—and then use that as a basis for my next blog post where ChatGPT acts as my editor, helping with flow and clarity.
And at the end of the day, AI isn’t the one sitting on the rowing machine. I am.
The Sub-7 Experiment: Meters, Mindset and more.
This is The Sub-7 Experiment…. It’s about the meters, the mindset, the technology, and the journey of seeing what’s possible when you combine all three.
The Sub-7 Experiment 