SINGAPORE - Sailors jostle for better positions but never check the clock at the finish line.

But windsurfer Amanda Ng is in a delicate race against time after the cruellest of April Fool's jokes threatened to derail her Olympic qualification.

The 27-year-old was in Oman for the Asian Olympic qualifiers when she slipped and fell flat while carrying her board up the steps after her final training session on April 1.

Unable to walk - she was later diagnosed with a Grade 2 medial collateral ligament tear in her left knee - the pain was so bad the next day she did not feel capable of starting the first of 13 races on April 3.

She feared the worst - that five years of preparation, a six-figure sum invested in the campaign, and a year's worth of unpaid leave from her role as an audit associate at Deloitte would go down the drain - and cried for a few hours.

Advised by coach Alistair Masters, Ng calmed down and pressed on, eventually fending off Filipino Charizanne Napa and India's Ishwariya Ganesh to clinch the single Tokyo 2020 ticket for Asia just seven days after her untimely tumble.

But Ng knows the Olympics are a different beast with an elite international field.

Her injury has complicated matters significantly. A full recovery takes 12 weeks of rest and rehabilitation without surgery, but she cannot afford to let up as she gears up for the July 25-31 RS:X event in Enoshima.

Ng, who arrived in Tokyo on July 9 after training five hours a day, six days a week in Weymouth, England over the last couple of months, said: "I was able to win in Oman despite my condition, but it is going to be a bigger field and a higher level at the Olympics, and physical condition plays a big part in how well I can catch the wind.

"I do rehab exercises every day to strengthen my quadriceps, hamstrings, glutes, and calves, and I'm hoping I recover gradually, but the reality is I also have to train almost every day to prepare for Tokyo."

In windsurfing, athletes use their legs to generate energy to pump their sails by bending and standing. With her injury, this was impossible for Ng, who is 1.70m and 54kg, in Oman.

She had to compensate with her arms as she not only had to master the wind and waves, but also control the sail - which feels much heavier than its stated weight of 18kg when propelled by 46km/h strong breezes - and the board against the currents. Her heart rate at competitions is in the 170 beats per minute range, but it felt a lot faster that week.

Her background in ballet - she danced from age four to 16 - helped with balance and coordination, and in the subsequent races, Ng was manoeuvring better with one leg and was able to make the moves required to edge ahead early on.

Much like the currents she navigates on the water, Ng is used to such ups and downs in sport and coming back stronger.

Her first taste of major disappointment was when she was not selected for the 2010 Youth Olympic Games on home soil. Two years later, she was the first reserve and missed out on London 2012.

"I felt like I wasn't progressing anywhere in windsurfing, so I thought, 'Why not just give the 470 a go?'," said Ng, who partnered Savannah Siew in the event at the 2015 SEA Games in Singapore.

She then teamed up with Jovina Choo at Rio 2016, where they finished 20th.

She added: "It was a good experience. Being back on a sailboat reinforced a lot of the sailing tactics you forget when you switch to windsurfing because it is so much about speed. Sailing with others also gave me fresh insights and perspectives I wouldn't otherwise get while windsurfing alone."

But the thrill of a faster class lured Ng back to the RS:X, and she is about to enter the history books as the Republic's first female sailor to compete in two different classes at the Olympics. Koh Seng Leong was the first Singaporean to do so when he competed in the men's 470 at Sydney 2000 and then the Laser at Beijing 2008.

Not bad for someone who used to throw tantrums when her father, former journalist Ng Wei Joo, took her to sailing lessons. Then seven and small-sized, Ng was terrified by the prospect of being out at sea alone and stopped going for training until she was 12.

"I'm proud of how I did not give up despite the early setbacks in my sailing career, which has helped me deal with challenges I have faced along the way," she said.

"It is common for sailors to change classes, but the achievement of going to two Olympics for different events is significant to me because of the journey I had.

"As much as I would like to finish higher than 2016, I can't really set a target because I am not even close to 100 per cent (fitness). But I know qualifying alone is not the finish line and I'm going to leave everything out there in all my races."

Singaporean sailors at Tokyo 2020

Amanda Ng, 27

Event: Women's RS:X (windsurfing)
World ranking: 32nd
Competition date: July 25-31
Olympic career: Second outing (2016)

Ryan Lo, 24

Event: Men's Laser
World ranking: 10th
Competition date: July 25-Aug 1
Olympic career: Debutant

Kimberly Lim, 24

Event: Women's 49erFX with Cecilia Low
World ranking: 31st
Competition date: July 27-Aug 2
Olympic career: Debutant

Cecilia Low, 28

Event: Women's 49erFX with Kimberly Lim
World ranking: 31st
Competition date: July 27-Aug 2
Olympic career: Debutant