Technology's great, but it's part of the reason waistlines are expanding. These days, many people do little physical work and rely on cars rather than their legs for getting around.

As a MacFormat magazine and TechRadar freelance writer, I'm immersed in technology daily, but my morning commute only involves going upstairs to my office. Therefore, unless I specifically make an effort to exercise, pounds (or kilos, metric fans) gradually creep on, even if I'm not shoving a chocolate bar in my face every night.

During 2009, exercise took a back seat, and I noticed myself becoming unfit. So I decided to do something about it – with the help of technology. For this article, I wanted to see if Apple's iPhone could help me get fitter rather than fatter.

Instead of spending time playing iPhone games, I'd spend a few weeks trying out exercise apps. Since the iPhone's expensive, the decision was made to restrict my app budget to a crisp (well, digital) tenner on the App Store – an 'impulse purchase' sum most people would be happy to spend to get in shape.

After researching options on the App Store, I decided on five apps – four exercise aids and one weight tracker.

The most expensive, at £5.99, was RunKeeper Pro, a GPS tracker for walking, jogging and running. Using the magic of technology, it logs where you go and integrates readings and progress with an online account.

At 59p each, GymFu apps CrunchFu, PushupFu and SquatFu were the cheapest. They're designed to train you over a couple of months to complete a number of 'reps' in a single session – 200 crunches, 100 push-ups and 200 squats, respectively. For fitness gurus, that might seem easy, but my arms tried to make a break for it on hearing the number '100' followed by the word 'pushups'.

GymFu

The weight tracker, Weightbot, is a £1.19 app with a fun, noisy interface, meaning even if pounds aren't shed, you won't be upset inputting your weight.

Although Weightbot initially proved the most fun app to tinker with, RunKeeper and the GymFu apps were engaging enough to get me excited about the prospect of using them for serious exercise.

WeightBot

The GymFu apps in particular seem designed for newbies, providing information about how to do good crunches, push-ups and squats. Along with mentioning warm-ups and stretches, they note you should take 48-hour breaks between training sessions, to give your body time to recover.

My plan therefore evolved to working with GymFu apps on alternate days and using RunKeeper in-between.