A fartlek session can be either the easiest or hardest thing you do all week. It’s a Swedish term meaning ‘speed play’, and it basically consists of fast, medium and slow running over a variety of distances.
Here’s how a typical fartlek session would work. After a steady warm-up, simply pick a landmark – for example a tree, lamp-post, or phone box – and run to it hard, then jog until you’ve recovered. Then pick another landmark, run hard to that, recover and so on.
There doesn’t need to be a set structure to the run. For your first quick burst you might choose a target that’s just 100m away and sprint to it flat out. Then for the next hard run you’ll see something 800m away and stride towards it at your 5K race pace.
It’s entirely up to you how hard or easy you make the session. Unlike track intervals, fartlek doesn’t require you to set a distance to run, or a time to recover. A watch isn’t necessary (although in the absence of landmarks you can use one to pick different times for your hard sections), as you listen to your body to determine your recoveries. After a hard spurt, jog until you’ve got your breath back, the lactic acid has drained from your legs, and your heart’s stopped thumping. Then go again.
If you want to add a bit of specificity, short, fast bursts will help you sharpen your pure speed, which is most important for races like 5Ks and 10Ks. Longer periods of speed help to raise your anaerobic threshold, which improves your speed endurance – ideal for 10-milers and half-marathons. In reality, though, both of these components contribute to good race performances at any distance from the mile to the marathon, so it’s best to mix and match the length of the bursts.
If you want to add an unexpected element to fartlek training, run with a friend and take it in turns to call the next fast leg.
i know tomorrow my thighs are going to kill but i found the experience enjoyable. Its great knowing that your body will get better over time with these sorts of things 