Foot racing is a popular activity in the United States. It is seen not only as a competitive sport but also as a way to exercise, to enjoy the cameraderie of like-minded people, and to donate money to a good cause. Though serious runners may spend months training to compete, other runners and walkers might not train at all. Those not competing with might run in an effort to beat their own time or simply to enjoy the fun and exercise. People of all ages, from those of less than one year (who may be pushed in strollers) to those in their eighties, enter into this sport. The races are held on city streets, on college campuses, through parks, and in suburban areas, and they are commonly 5 to 10 kilometres in length.
The largest foot race in the world is the 12- kilometre Bay to Breakers race that is held in San Francisco every spring. This race begins on the east side of the city near San Francisco Bay and ends on the west side at the Pacific Ocean. There may be 80,000 or more people running in this race through the streets and hills of San Francisco. In the front are the serious runners who compete to win and who might finish in as little as 34 minutes. Behind them are the thousands who take several hours to finish. In the back of the race are those who dress in costumes and come just for fun. One year there was a group of men who dressed like Elvis Presley; and another group consisted of firefighters who were tied together in a long line and were carrying a firehose. There was even a bridal party in which the bride was dressed in a long white gown and the groom wore a tuxedo. The bride and the groom threw flowers to bystanders, and they were actually married at some point along the route.
As used in the passage, the word “strollers” refers to: