Tough Mudder is an 18km obstacle course challenge designed by British Special Forces to test the all round strength, stamina, teamwork and camaraderie of NSW's toughest.

Thousands will descend on the bushland obstacle course to tackle obstacles including ice water, a greasy quarter-pipe, live electrical wires and a whole lot of mud.

Over the past six months, the course designers have been hard at work designing a new course layout with plenty of new challenges.

Some of the never before seen obstacles include 'Fire in the Hole', an almost vertical 10m slide that shoots competitors through a wall of fire and propels them into a a pit of muddy water and 'Arctic Enema' a pit of below freezing water that forces athletes to swim in and under the iceberg abyss to get out the other side.

'Electroshock Therapy' will also be another new obstacle which is a gauntlet of 10,000 volt charged dangling wires participants must barrel through to get to the finish line and competitors will also face the 'Leap of Faith' a flying leap over a pit of water to a hanging cargo net.

For more information, visit www.toughmudder.com.au/events/2014-sydney-southern-highlands