It is certainly true that Fartlek running can be widely adapted, both by individuals and by groups. But for friends or training partners who love to push each other, Fartlek training is perhaps the best method available. It is fun, challenging, and rewarding.
Just tell your above-mentioned friend(s) to get their running shoes and plan to meet you for an off-road run. Get yourself to some beautiful park with good trails and footing, and get ready to work.
Running against each other for intense periods of fast and then off-pace running can be an incredibly beneficial workout. Choose a distance that makes sense for your training, and go at it. Nothing could be better, perhaps, than this sort of a run once or twice a week. Push hard and fast in the quicker portions (to the bend in the trail up ahead), and run slow enough to speak a few words during the slower portions (to the edge of the tree line). But try to win each faster section while not falling too far below a slow race-pace at any time. The benefits are remarkable, and the competition and fun is great. It should bring back memories of a long game of tag on the playground.
If you are just in it for fun and the health benefits, you won't be disappointed. But if you are in it for serious training, then it is hard to get the competitive juices flowing more than in this sort of Fartlek.
On a humorous note, you might say that group Fartlek running is the only way you can fartlek.
If you enjoy this sort of low-brow humor then grab a shirt to share the fun!
DISCLAIMER:
Persons choosing to utilize these sessions do so at their own risk. You agree to assume the risks of such training, and further agree to hold harmless Fartlekers from any and all claims, suits, losses, and/or related causes of actions and damages, including, but not limited to, such claims that may result from my injury or death, accidental or otherwise, during or arising in any way from copying and/or implementing these session suggestions. These session concepts have been offered as ideas for training, and are not intended to be followed without the approval of your physician.