Swimming at the 1968 Summer Olympics – Men's 100 metre freestyle  The men's 100 metre freestyle event at the 1968 Olympic Games took place between 18 and 19 October. The competition used a three-round (heats, semifinals, final) format. The advancement rule followed the format introduced in 1952. A swimmer's place in the heat was not used to determine advancement; instead, the fastest times from across all heats in a round were used. There were 9 heats of between 6 and 8 swimmers each. The top 24 swimmers advanced to the semifinals. There were 3 semifinals of 8 swimmers each. The top 8 swimmers advanced to the final. Swim-offs were used as necessary to break ties. This swimming event used freestyle swimming, which means that the method of the stroke is not regulated (unlike backstroke, breaststroke, and butterfly events). Nearly all swimmers use the front crawl or a variant of that stroke. Because an Olympic size swimming pool is 50 metres long, this race consisted of two lengths of the pool. There were 9 heats in this category. 24 fastest swimmers from the heats advanced to the semifinals.  8 fastest swimmers advanced to the final. Zorn matched the previous Olympic record of 53.4 seconds in semifinal 2 before Wenden broke that record with a 52.9 second time in semifinal 3. Zorn lead the field at the 50 metre turn, but weakened by a week long illness, faded and finished last.