and found this:
As the 64-year-old Puttemans knows only too well. He was in the Olympic 10,000m final in Munich in 1972, in which Lasse Viren fell in mid race but won in a world record time, 27min 38.4sec. Puttemans finished second behind the Finnish policeman. "He was just too fast for me on the last lap," the Belgian said.
It might have been different had Puttemans not expended so much energy in his heat. He and Dave Bedford ran so fast the great British hope turned to him with 2,000m to go and said: "Let's go for the world record." "We could have broken it easily," Puttemans reflected, "but I said to Dave, 'No, it's only the heat'. Maybe if we had run easier from the start in the heat it would have been different for both of us in the final."
Can some of the old timers on here talk about what the heat was like? what was the record why were they running so fast? Would love to hear your insight.