The air was July warm and the sun added heat when it broke free of the thin clouds. The road stretched out ahead of me, the tarmac shimmering in the sun.

I’m running 21 miles. That’s the plan for today. And if I manage it, it’ll be the longest run I’ve managed for a while.

There’s a problem, though.

My pace is down on where I’d like it to be. And every time I push it back I start to feel the strain.

I force myself to relax. I’ve run a long way before. I know panicking doesn’t fix anything. I take deep breaths followed by big exhales to oxygenate my lungs. I keep my head up and look around.

It is a beautiful day. And unlike last time I tried this distance, the wind is gentle, almost calm. I can’t say the same for my stomach.

There’s stomach cramps hitting me every now and then. I try not to worry because I’ve had these before. I focus on putting one foot in front of the other.

Another mile pings on my watch. I nod with satisfaction. That’s 12 and I’m ok, I say to myself.

I decide to busy my mind with numbers for a while. Nine miles to go. I’m averaging 9 and half minutes per mile. That’s about right for a long run based on my current form. Then the pain kicks off in my right knee.

I’ve been battling with knee pain for a while. I tend to run through these kind of niggles. So that’s what I do now. I ignore it, gulp in some more air and keep running.

Now the cramps in my stomach kick off again. They are worse this time. It slows me down while I try to run tall and absorb the pain.

Mile 15 pings on my watch. I’m hurting but I’m still moving. It occurs to me that’s a major point. I’m still moving. I figure the next 6 miles should be easy. Another 100 yards makes me realise I’m an idiot.

The last few miles are going to be hard.

The sun shows its face with more heat. I love the summer and try to enjoy it. But the stomach cramps are almost constant now. And I’m feeling dehydrated.

I let my mind wander over the learning points.

First, I’m not fully ready to cover marathon distances.

Second, I need to find out what’s going on with the stomach cramps.

Third, I need to work on speed endurance to bring my pace up to something more like I want it to be.

The bottom line is, running a long way hurts. The training required is specific and that’s what this run identified.

I did make it for the whole 21 miles. But the last few miles were painful and slow. By the time I got home, the run didn’t feel like a success. But the truth is: it wasn’t likely to be.

This was my second recent attempt at something longer than 20 miles. For the first attempt, I made it to 20 miles and had to stop. Today, I got the whole thing done, but painfully slowly.

There is now a clear plan. I have to keep pushing on the long runs. I have to run some high intensity sessions to boost my speed endurance. And I have to figure out what’s happening with my physical condition as the number of miles adds up.

These are all manageable things to figure out. They form the basis of my plan to get to full marathon distance.

Running a long way requires fixing the fundamental problems of energy and hydration. And the ability to endure the miles can be trained for. After that, marathons are a done deal.