2016 Rio Olympics - Cycling BMX - Preliminary - Men's BMX Seeding Phase Runs - Olympic BMX Centre - Rio de Janeiro, Brazil - 17/08/2016. Sam Willoughby (AUS) of Australia competes. REUTERS/Paul Hanna

2016 Rio Olympics - Cycling BMX - Final - Women's BMX Final - Olympic BMX Centre - Rio de Janeiro, Brazil - 19/08/2016. Alise Post (USA) of USA reacts after winning the silver medal. REUTERS/Paul Hanna

2016 Rio Olympics - Cycling BMX - Final - Women's BMX Final - Olympic BMX Centre - Rio de Janeiro, Brazil - 19/08/2016. Alise Post (USA) of USA reacts after winning the silver medal. REUTERS/Antonio Bronic

2016 Rio Olympics - Athletics - Preliminary - Women's 4 x 400m Relay Round 1 - Olympic Stadium - Rio de Janeiro, Brazil - 19/08/2016. Novlene Williams-Mills (JAM) of Jamaica leads the race. REUTERS/David Gray

2016 Rio Olympics - Athletics - Preliminary - Women's 4 x 400m Relay Round 1 - Olympic Stadium - Rio de Janeiro, Brazil - 19/08/2016. Francena McCorory (USA) of USA passes baton to Phyllis Francis (USA) of USA REUTERS/David Gray

2016 Rio Olympics - Athletics - Preliminary - Women's 4 x 400m Relay Round 1 - Olympic Stadium - Rio de Janeiro, Brazil - 19/08/2016. Competitors pass their batons for the third leg of the race. REUTERS/Lucy Nicholson

2016 Rio Olympics - Basketball - Semifinal - Men's Semifinal Spain v USA - Carioca Arena 1 - Rio de Janeiro, Brazil - 19/8/2016. Deandre Jordan (USA) of the USA dunks. REUTERS/Ezra Shaw/Pool

2016 Rio Olympics - Boxing - Semifinal - Women's Middle (75kg) Semifinals Bout 264 - Riocentro - Pavilion 6 - Rio de Janeiro, Brazil - 19/08/2016. Claressa Shields (USA) of USA celebrates after winning her bout against Dariga Shakimova (KAZ) of Kazakhstan. REUTERS/Peter Cziborra