Paralympian Darren Harris, from Sutton Coldfield, represented Great Britain in judo at Beijing 2008, and in football at London 2012 - and is taking on the inaugural Birmingham International Marathon in October. Here, he shares his hints and tips for preparing for the iconic distance.

Even for someone who has spent a lifetime training, knowing when to run or rest, is a difficult question to answer. So what happens when you get it wrong, as many of us have done over the years?

Overtraining

Doing too much, too soon might seem the least likely problem you will encounter.

Once you catch the running bug, yes it really does happen, it's easy to become addicted to the rush of happy hormones swilling around your brain, as well as the personal bests, kudos and comments posted on your online tracker.

But avoiding the so-called terrible too’s is essential to keeping your body in one piece and your mind looking forward to the next session.

Undertraining

On the other hand, if you haven’t begun your training yet, no matter how many times you put off starting, the race date won't change.

It’s tempting when too little, too late is the phrase echoing inside your head, to try and make up for lost time, but cramming your training in last minute, will simply leave you feeling jaded with no time to experience the benefits of those final sessions.

Goldilocks Principle

Whether you are a beginner, advanced or somewhere in between, there's a programme for you that’s just right, that takes into account your particular running level and personal circumstances.

I chose a 17-week training program for myself. But there’s even a four-week marathon plan out there, if your goal is to simply get round the course.

Not only is a marathon a very long way, it's also an incredibly long time on your feet. So getting the right balance between distance and time is crucial.

So check your calendar, work out where you are, and make sure to follow a program that’s just right. It will reduce your chances of injury and illness, and improve the likelihood of you crossing the finish with a smile ready for the camera on the line.