She used to train with the boys – big boys, who were boxers during the day and bouncers in bars at night. Ada Kok was a teenage swimming phenom, asked to join the Dutch national swimming team at the age of 13, but in the early 1960s in Amsterdam, athletes were on their own.

“In those days, you just had a swimming coach but nothing for any condition training. The coach of the boxing team helped me. I ran in the park with the other boxers. I skipped rope. And my friends made sure that boys didn’t give me trouble when going out in Amsterdam because they’d tell them, ‘I’ll punch you in the nose if you don’t do right by her’.”

Inspired by her sister, who competed on the Dutch swim team at the 1960 Rome Olympics, Kok became the premier butterfly swimmer in the world, setting the world record in that discipline in September, 1963, and again in May, 1964. At the age of 17, Kok was the favorite going into the 1964 Summer Games in Tokyo.

Nearly matching her world record time, Kok swam an excellent race in the 100-meter butterfly finals. But she lost to Sharon Stouder of the USA, who broke Kok’s world record. Going into the finals, Kok expected to win, but in retrospect, she now knows she was unwittingly swimming upstream against a US team that was more prepared and more experienced than any other team.

“I was very disappointed,” Kok told me. “I was the world’s record holder for years, and I was training hard for this event. I didn’t know Sharon Stouder. I didn’t think about my competitors. I was confident, not arrogant. But I was also naïve.”

In the end, no other country had the resources to support a swim team like the USA at the time. Not only was the Netherlands 0.4% the size, 6.3% the population, and 43% of the per capita GDP of the United States in 1964, the US had the swim clubs, the coaches and the access to international competition that very few other athletes in the world had.

“They were more professional,” said Kok of the Americans. “They had paid coaches. Mine was a volunteer, who had a regular job. Our swim federation didn’t have the money to send us abroad so we competed in nearby countries traveling at minimum cost.”

And yet, the Dutch women’s team still proved to be a powerful force, winning silver in a team race in the women’s 4X100 meter medley relay, a competition where four swimmers swim two lengths of the pool each in four different styles in this order: the backstroke, the breaststroke, the butterfly stroke, and freestyle (which means any style other than the previous three).

As a demonstration of American dominance, the US swim coach did not even use their top swimmers in the heats. And the four swimmers who swam in the finals set an Olympic record, finishing over three seconds faster than the silver medalists, the Dutch. Making it close was Ada Kok, who got some measure of revenge against Stouder by swimming the third leg butterfly stroke over 1 second faster than the American in the finals. “The silver medal for the team was a positive surprise,” said Kok. “We couldn’t get anywhere near the Americans, but to be second as a team was fantastic.”

Kok would regain her world record in the butterfly in August, 1965, as well as win the gold medal in the 200-meter butterfly in Mexico City in 1968. But she was happy with her results in 1964. “You’re always pleased to get a medal. When you’re on the podium, and you see it and touch it, it’s wonderful.”