Looking to Reinvent Your Running? You need our Top Ten Trail Running Tips. But first, read this.

Interval training is one of the fastest ways to get fit, says Ryan Sandes, pro trail runner. Here’s how to slash your times

One minute hard, one 
minute easy
“You run as fast as you canvand you do it as many times as you can,” says Calitz. This spikes your heart rate, he says. Subtract your age from 220, this is roughly 90% of your maximum heart rate. The brief recovery time allows you hit this as often as you can.

Three minutes hard, one 
minute easy
“This mimics running on a trail where you run uphill for an extended amount of time and you only have a short recovery period.” He runs these at about three minutes a kilometre. “You need to be able to hold that intensity – albeit a lower intensity – for a longer amount of time.”