Participants cross a cold water pool during the Strong Race competition near Tukums May 4, 2014. About 6500 people competed in this extreme running race, which includes cross-country running, elements of agility and power discipline. (Photo by Ints Kalnins/Reuters)

A woman reacts as she competes during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participants cross a cold and muddy water pool during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participants cross obstacles during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participants cross obstacles during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participants cross obstacles during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participant wears a helmet as he swims in the cold and muddy water pool during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

A participant crosses an obstacle during the Strong Race competition near Tukums May 4, 2014. (Photo by /Reuters)

Participants run during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participants cross cold and muddy waters during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)

Participants cross a cold water pool during the Strong Race competition near Tukums May 4, 2014. (Photo by Ints Kalnins/Reuters)