From Easter Monday Mr Klein, of the Otago Racing Club and NZ Jumps Inc, along with former top jockey Lance O'Sullivan, Simon Cooper of New Zealand Thoroughbred Racing, and Jason Fleming of Hawkes Bay Racing, will start running a lap of every thoroughbred racecourse in New Zealand - 51 in all - ending at Ellerslie on April 14 for Easter Handicap Day, for the spinal cord charity CatWalk.
The nature of the challenge meant running around a track, jumping in the car for a couple of hours and then doing it again up to 12 times in a day.
"It's really difficult to train for. No-one has any idea how to train for it," he said.
His best solution so far had been avoiding taking a rest day, as he would for a regular running event, instead training every day, although he acknowledgeg a two-week holiday in the United Kingdom catching up with friends and family had made that difficult.
"None of us has any idea if this is achievable. On paper it should be."
The tracks vary in length so the runs would range from 1.6km to the 2km at Riccarton and Ellerslie. About 20 minutes at each venue had been allowed.
"One good thing is they're mostly flat - no hills to encounter," he joked.
Some of the runs would be done at night with headlights on, but he expected tiredness to be the biggest challenge. On the third night, as they crossed from the South Island to the North Island, they were expecting to get only three hours sleep.
"I think we'll be pretty jaded that day."
Mr O'Sullivan, patron of the CatWalk Spinal Cord Injury Trust, said the runners hoped to raise at least $1 from each person they meet on the way for the trust, which supports finding a cure for spinal-cord injury.
"We recognise the potential dangers our jockeys and track riders face every day."
They believed the late Jack Glengarry ran around all the courses in New Zealand, but in stages - not in six days, he said.
"For four guys between the ages of 37 and 52, it will be a great challenge."
The team will run 12 tracks on the first day beginning in Gore at 6am on Easter Monday, visiting Wingatui about 3pm and finishing in Timaru 9.20pm.
