“Speed up to the energy zone. You have completed half your workout.” This is not my personal trainer – this is my mobile phone.

When I say mobile phone, I don’t mean the voice of a friend calling me up to jeer at my misery. This is my actual phone.

Part of me finds it hard to take seriously but I am jogging along the South Bank in London on a crisp, sunny Sunday afternoon, out of breath and red in the face, being barked at to speed up by my phone. This is miCoach, the phone that wants to make me fit. Or, as I now think of it, the phone that wants to humiliate me.

In the race to think of the next must-have accessory for your mobile, Samsung and adidas have added a virtual personal trainer to the usual list of MP3 player, games and camera.

Billed as a “total coaching system”, it monitors your heart rate, keeps track of how far you are running and how many calories you burn while you pound the streets. To add insult to injury it also quips “motivational” comments on your progress in a gratingly cheerful American accent. “Warm it up. OK, let’s go.”

For someone of my deep level of unfitness, miCoach is not a gadget I ever thought I’d hold in my hand, let alone strap on my arm and take running.

But as I fix the heart monitor around the top of my ribcage, strap the mobile holder to my upper arm and slip the “foot pod” pedometer on my running shoes and select a suitably upbeat music track, it could be just what I need to launch my new fitness regime.

But first the phone needs to assess my fitness. This involves running “as fast as you can” for a mile. I can’t run very fast. Then I have to walk for a minute. The time it takes my wildly beating heart to return to normal reveals my fitness.

Being naturally quite slim, I can usually get away with hiding the true level of my unfitness. But I can’t hide from this machine. I finish the run and it gives its verdict: “Beginner.” However, I’m reassured. At least my phone sees me for who I am rather than sets me impossible goals.

The next step is to log on to the website. Here I find more than 200 programs, but it hasn’t factored in the possibility of someone who has never run before.

With the knowledge of my age and weight, it will set me a personal training plan, depending on the goals I want to achieve. After each run I download the results and it can assess my progress. I opt for the first option – the rather humiliating “learn to run”. It sets me 56 workouts. I really am bad.

But I’m ready to go. My first session involves a mixture of running and walking. Despite my first impression that the whole idea is nothing more than gimmickry, I’m beginning to think there might be something in it. Let’s face it, most of us can’t afford a real personal trainer but we still need a plan to work to. And this could be the next best thing.

I finish the run. “Nice work,” it says.

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