Train too hard, and you’ll probably burn out or get injured. Train too easy and you simply won’t make the most of your potential – though hey, that’s perfectly okay too! But if you do want to try and get faster and bust out some PBs, then you do also need to know how hard to push on hard sessions – and then how easy to take it on easy runs.

Training by heart rate is one good way of getting it right. Using this calculator is another.

How to use the training pace calculator:

It’s very simple, just tap in a recent race time and press ‘calculate’.

The calculator will automatically show what sorts of speeds you should run the different components of a training week at (though don’t do them all in one week…!)

Click here for the full article: Runners World Training Pace Calculator