He's a fitness junkie who takes part in 10km races four to eight times a year. He also does weight training once a week.
But last Saturday at Sentosa, building surveyor Adnan Daeng, 40, had to do both simultaneously for the Commando Challenge run.
Not only did he have to run 7km while carrying a 15kg bag, he also had to tackle obstacles along the way.
He said: "I like to take part in races to test my fitness, and this was the toughest so far."
Organised by MegaZip Adventure Park, the Commando Challenge is a race that features an obstacle course similar to those used in physical selection tests that British soldiers undergo to qualify for elite military units.
This is the second year that the event has been organised, and there were over 2,700 contestants this year.
Mr Daeng took part in the Extreme Commando, the toughest of the three routes in the Commando Challenge.
Contestants had to tackle 28 obstacles - including aerial obstacles, zip wires and water crossings - along a 7km course while carrying a 15kg bag.
Mr Daeng said: "Running with the added weight made it more difficult."
The two other routes in the challenge were the 5km Commando Course with 12 obstacles, and the 2.5km Teen Commando with eight obstacles.
One obstacle was the Electric Gauntlet, where contestants got a static shock if they touched the yellow wires at the station.
MegaZip Adventure Park marketing manager Edward Fearn said: "Although the voltage seems high (10,000 volts), the station is perfectly safe as it has a low amperage. It only feels like a static shock when you touch the wires."
Ngee Ann Polytechnic student Erika Maguicay, who took part in the Commando Course, said the toughest obstacle was The Ice Plunge where contestants had to submerge themselves in a tank of ice water about 2.5m deep.
The 20-year-old said: "The cold was traumatising. I felt like I had a brain freeze. But the race was a fun experience and I enjoyed the challenge."
The list of winners is still being tabulated by the organiser.
Mr Gavin Barnes, the race director and a former specialist trainer with the British Forces, said that the objective was to make the course achievable, fun and challenging.
He added: "Judging by the enthusiastic feedback from the competitors, we met those expectations."
This article was first published on November 18, 2014.
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