If you want to go faster, run shorter. “Cut your overall weekly distance by 10 per cent,” says John Stanton, author of Running Room’s Book on Running. Replace this distance with hill and speed work. You can try interval training or tempo runs where you run at 80 per cent of you maximum heart rate for a shorter distance that you would do on a traditional run.
Do this for a month or two and you can expect to boost your speed by up to 15 per cent.