Running with the pack: Social fitworking

"The first element is competitive as you have a challenge to complete, secondly it clears your head, third it's a fun journey getting there and the fourth thing is the social aspect - it's a bit like a dating centre!" says Gareth Cole, head of education at The Third Space gym which runs Grand Circuit classes where members must race each other to do 1,000 reps in 45 minutes.

But with competition comes socialising, and Facebook is abuzz with social fitworking activity. Warrior Dash arrives in Surrey from America next summer and is "liked" by 732,255 on Facebook. The idea is that teams race each other over 12 obstacles and five kilometres of extreme terrain.

Tough Mudder, another endurance event which has swept across America, hits the UK in May 2012. With 1,220,733 current Facebook "likes" and nearly 150,000 Mudders signed up abroad, its founders Will Dean and Guy Livingstone plan to send teams running across a 12-mile obstacle course which includes stinging nettles, waist-high swamps or 10,000 volt shock wires.

Last month, I visited Hurlingham Park in Fulham for a trial run where I found myself crawling through mud, army-style, heaving myself up a three-metre-high wooden Everest wall and doing press-ups and star jumps as part of a 10-strong group of varying fitness levels. While it was easily the hardest, muddiest fitness session I've tried, it was also the most fun, and I'm looking forward to May for the real thing.

Finally, there is GO Mammoth, a social sports club started by Londoner Luke Mohr, who saw the potential for making team sport accessible and enjoyable here. Members pick from various sports including football and dodgeball, signing up in teams or individually to an eight-week league, and Mohr has seen membership rise from 100 to 3,000 members within a year.

"Being part of a team gives people a strong sense of belonging," Mohr enthuses. "It's much more fun to share experiences with others - whether actually competing together on the playing field, chatting in the pub after the game, or posting photos on Facebook the following morning, and the mix is 50:50 male to female."

So if you feel the need to run with a new pack, it's time to train en masse.

* Warrior Dash, June 23, £40 before November 30, www.warriordash.com

* Tough Mudder, May 12, £90 before December 31, www.toughmudder.co.uk/

* GO Mammoth run ongoing events, £65/person/season or £350/team (8-9 weeks), www.gomammoth.co.uk

* Grand Circuit class, The Third Space, £129/month, thethirdspace.com