Boot camps lasting a few hours at the hands of qualified fitness instructors are rightly regarded as one of the most demanding ways to get in shape.
But they have nothing on the 18-hour non-stop gruelling black belt gradings a group of young Tauranga karate students under went over theweekend.
Students attempting to pass their black belt test in the Mile High karate system began at 6pm Friday and continued testing through the night with no sleep, training constantly till the conclusion at midday Saturday.
The group aged from 9 to 18 were put through their paces by Tauranga Martial Arts Master Sifu Grant Buchanan and the training included a 10km march at 11pm on Friday, a training session on top of Mauou at sunrise on Saturday, and varied practice sessions at Queen Elizabeth Youth Centre in forms, self defence and weaponry skills.
All this follows an intense black belt prep cycle over the last month and is the culmination of a minimum of four years training at Buchanan's Tauranga studio.
Buchanan, a Sixth Degree black belt, says black belt gradings are as "tough as it gets".
"I have been a guest and officiated at gradings for well over 800 black belts and have never heard of anything as gruelling or as thorough as the process our students undergo," he said.
"We have five students under 13 in this twice yearly event, three of whom have attempted this challenge twice before. It is a measure of stamina, focus, discipline and spirit."
The gradings in Tauranga for the Mile High Karate Studios in New Zealand are a highlight for all the students as they have the opportunity to train with the Technical Director for New Zealand in Senior Master Paul Bryant - an Eight Degree black belt.
Mile High Karate was founded 35 years ago in Denver.