A boy heads towards the Jiu Jitsu school in Santa Marta slum of Rio de Janeiro, Brazil, Aug. 23, 2012. There is a Jiu Jitsu school in Favela Santa Marta in Rio, established by Master Rogerio Guedes, who now has more than 60 children practising the sport in the school. (Xinhua/Weng Xinyang)

Local residents watch children practising Jiu Jitsu in Santa Marta slum of Rio de Janeiro, Brazil, Aug. 23, 2012. There is a Jiu Jitsu school in Favela Santa Marta in Rio, established by Master Rogerio Guedes, who now has more than 60 children practicing the sport in the school. (Xinhua/Weng Xinyang)

A teacher instructs Jiu Jitsu techniques in Santa Marta slum of Rio de Janeiro, Brazil, Aug. 23, 2012. There is a Jiu Jitsu school in Favela Santa Marta in Rio, established by Master Rogerio Guedes, who now has more than 60 children practicing the sport in the school. (Xinhua/Weng Xinyang)

Master Rogerio Guedes teaches Jiu Jitsu techniques in Santa Marta slum of Rio de Janeiro, Brazil, Aug. 23, 2012. There is a Jiu Jitsu school in Favela Santa Marta in Rio, established by Master Rogerio Guedes, who now has more than 60 children practicing the sport in the school. (Xinhua/Weng Xinyang)

This multi-exposure photo shows children practising Jiu Jitsu technique in Santa Marta slum of Rio de Janeiro, Brazil, Aug. 23, 2012. There is a Jiu Jitsu school in Favela Santa Marta in Rio, established by Master Rogerio Guedes, who now has more than 60 children practicing the sport in the school. (Xinhua/Weng Xinyang)