It's hot and humid and she's hurting but Rachel See won't stop running. She's been nauseous in Kuala Lumpur through the second half of the marathon but she won't stop. Her stomach cramps but she won't surrender. Her legs start to seize towards the end and she'll slow to a walk but she won't quit.

With 8.9km left and one last loop to go it's "tempting" to exit the race quietly. Anywhere else, at any other weekend marathon, she'd abandon it. "If it was for personal glory, I'd pull out," she says.

But this is the SEA Games. "Of course it's different," she says.

She's running for a cause larger than herself. She's running for Singapore. She's running for fans who "have come all the way from Singapore" and whose shouts she can hear. So she'll cramp, and walk, and time 3hr 46min, which is about 48 minutes slower than her personal best, but she'll find the courage to finish.

And then she cries.

A lot of young people will weep this fortnight for this is the SEA Games. A sprawling, emotional, energetic multi-sport showdown, where everyone's chasing something - rivals, dreams, personal bests, medals. Some will find practice pays, some will discover bad luck has no sense of timing.

Debbie Soh, who wins three golds and two silvers, misses the synchronised swimming solo technical gold by 0.0133 of a point and Yong Yi Xiang loses wushu bronze by 0.01. But at least they get to compete. Tan Sze En, the gymnast, hurts her ankle and doesn't even get to walk a beam or tumble on the floor and show you her polished craft. Maybe she cries.

The Singaporean footballers do cry. So do the netballers, the men marathoners, the synchro girls and table tennis' Pang Xue Jie. Tears are gender blind, crying is status-free. Women, men, losers, winners, it makes no difference, they all cry.

It's elation, exhaustion, disappointment, relief. It's two years of commitment that's been rewarded - or hasn't been - and now it's done. We think we understand but it's only if you put your entire being on the line, almost every day, for one moment in the future, that you appreciate the crying.

Big Games are loud, crowded and tense, full of anxious parents with shaking cameras and coaches whose stoic faces rarely reveal their agitation. Athletes are familiar with the anxiety of competition and the occasional hollowness of their insides, but this is slightly different from their normal seasons, this is every two years, this is the bigger spotlight, this is a chance.

Sport, on a weekly basis, has an inherent hierarchy, wherein football comes first and Formula One, basketball, tennis follow, and trampoliners are never heard of. But at a big Games we briefly abandon our snobbery and acknowledge all our athletes because they are playing for us. We notice the wushu exponents and silat competitors, the fencers and ice skaters, all of them with this opportunity to show their nation who they are and what they can do before Federer politely shoves them off the sports pages.

The big Games are an introduction to and a celebration of sport. What's with those water polo caps? To identify players. How do those synchro girls smile and look so relaxed when their muscles are complaining? Hard work.

Everyone comes armed with talent and only tenacity and tactics might separate them. But what will work? Marathoner Soh Rui Yong cuts 20-30 holes in his vest for no apparent scientific reason beyond being lighter. As intriguingly, when he runs, he hangs onto his water bottles longer than normal. His competitors might stride, sip and toss their bottles, but at every one of his eight drink stations Soh picks up a 500ml bottle of isotonic drinks and carries it for roughly 400m and finishes it. He might want to vomit several times and yet he wins.

Soh cries. Mok Ying Ren, his marathoning rival, almost does. "I held it in," he insists. He will not return home with a medal but with a memory that is lovely, surprising and humbling. During the race he will be cheered by Malaysians and later they will ask him to sign - in one case an iPhone - and pose for pictures and by the end he's made roughly 150 new friends.

This is what matters most, not the medal tables and the disputes about flags, but the human tales. Stories of striving, stories of being challenged, stories like Dipna Lim-Prasad.

The 400m and 400m hurdler had recovered from a month-long illness in July, her blood count low, visiting the hospital for frequent blood tests, and was recovering her form when she fell on her knee on Aug 12 in Japan. "There were abrasions," she texted, "a tear in a hamstring tendon and bone bruising".

For athletes who look to control everything - when they sleep, what they eat - this was life beyond her control. You can't plan illness, you can't predict injury, you just adjust. She can't postpone the Games, she has no choice, she has to run.

Today she starts. And she'd better be in full cry.