The pain in his ankles when he was training for a marathon last year was intense.
Army regular Izaac Koh, 33, decided to change his running style and bought a pair of super-light shoes which cost him $110.
He ran fewer than 10 times in those shoes before hanging them up.
"My ankles were hurting badly," he said.
So he bought another with conventional cushioning for $120.
It alleviated the pain, but not for long.
He said: "Over a distance of 42km (for the marathon), the pain was eight or nine out of 10. I walked the last 12km, I could hardly feel my ankles – it was that painful."
What Mr Koh did not realise was that his right leg was shorter than his left by 1cm and that he had a high arch – these two factors contributed to the pain in his ankles which lasted six months.
He required customised insoles, not new shoes or a different running style.
Changi General Hospital podiatrist Hu Wenyan, 26, said that people with high arches are prone to "stress fractures" along the metatarsals, or mid-foot bones, because they are unable to absorb the impact on the knees while walking or moving.
Mr Koh’s experience is not unique.
As more people here take up running and other sports, doctors and podiatrists are seeing more foot and other leg injuries.
Changi Sports Medicine Centre consultant Roger Tian, 42, told The New Paper that several ankle and knee problems are due to "poor footwear selection".
The sports physician said runners are also trying to do "too much too soon".
Explained Dr Tian: "They fail to condition their bodies, or they wear the wrong footwear or shoes with worn-out soles. These can cause injuries."
The injuries are not just confined to the feet and lower legs, but also the hips, pointed out Ms Hu.
Podiatrist Tye Lee Tze of The Podiatry Centre wasn’t surprised by Mr Koh’s painful experience.
"When you’re running, the impact on the heel is three times your body weight (on the joints).
"So if a 50kg woman runs 5km, that’s 50 times three, and over a distance of 5km, that’s some 2,000 to 2,500 footsteps."
He added that this is roughly equivalent to lifting a 150kg weight 2,000 to 2,500 times; therefore, wearing the correct shoes is important.
Dr Tian said the impact on the feet can even go up to five times the body weight.
"A lot of people don’t realise this, but you have to build up muscles to take the load," he said.
Mr Koh found out about his high arch and about his right leg being shorter when he consulted a physiotherapist and a podiatrist, whom he saw for three months at Changi General Hospital.
A podiatrist made a mould of Mr Koh’s feet and sent it to a lab for customised insoles.
Mr Koh spent $166 on one such pair and is looking forward to receiving them this week.
So does the pain go away completely?
Said Mr Tye: "In any weight-bearing activity, especially running, rarely are you going to be 100 per cent pain-free.
"The goal of treatment is to enable the patient to continue their activities in a functional (and) manageable way."
By Esther Ng, The New Paper