If ever there was an incentive to push yourself to your absolute physical and mental limits, with gas masks and more than 2000 exercise repetitions thrown in, then Mount CrossFit athletes might have the answer.

On July 5 members will prepare to do it tough, yet smiling, for five-year-old James Reid, helping raise funds towards a $150,000 life-changing operation.

Event organiser and Mount CrossFit member Aaron Williams says the WOD for James Reid will be a true battle of attrition. Photo: Bruce Barnard.

James, from Maketu, has spastic quadriplegia cerebral palsy, epilepsy and hydrocephalus, a blockage to the flow of cerebrospinal fluid. This means Sonja and Don Reid's little boy is unable to crawl or stand without support, and can only take assisted steps with great difficulty.

Event organiser and family friend Aaron Williams, also Maketu born and bred, saw how heavy hitting this is for the family. He wanted to put his hand up and help out through the sport he has known for the last four years.

Cruel, bordering on sadistic - call it what you will - but Aaron has created what he believes is the perfect workout to reflect the mental and physical challenges that James is going through.

In the Workout of the Day (WOD) Challenge, teams of up to four will tackle more than 2000 repetitions of exercises, including slam balls, pull-ups and burpees, coupled with a 10km row, log carries, 1km lunge walk with gas masks and four tonne of lifts.

Envisaged to take between four and five hours, the workout will also enhance teamwork and team building.

'This will be the hardest workout that any member has ever done,” quips the Tauranga Police Senior Constable.

'It's not going to be easy because James isn't doing it easy.”

The event has proved popular already, with 10 teams signalling their interest in the first 24 hours, although Aaron is hopeful about 30 teams will step up to the fundraising plate.

Mount CrossFit coach Luke McGruer is rumoured to do the full workout individually if club members can drum up $1000, while other coaches are doing it in pairs.

Either way, everyone is going to be pushing themselves to the limits and feeling the burn afterwards.

'James has limited mobility and I'm pretty sure come Monday all of the members will be feeling exactly the same.”

So far, more than $90,000 has been raised and the family is desperately hoping to reach their $150,000 target by September. For more information follow his Facebook page Team James Whatever It Takes or http://givealittle.co.nz/cause/teamjames.

The event is on July 5 at midday with teams of up to four of any level or experience able to enter at $100 per team. For more information or to enter go to Mount CrossFit.