The 16-year-old, who rose to fame when she took Olympic gold in the 800 metres freestyle at London 2012, won the women's 400m freestyle, 800m freestyle and 1500m freestyle at the National Championships last month.

These performances included a personal best in the 1500m final of 15min 47.15sec - the fastest time in the world this year, a national age group record in her 400m victory and a second-place finish in the 200m.

Ledecky becomes the first American woman to qualify for the International Swimming Federation (FINA) World Championships in the 200m, 400m, 800m and 1500m freestyle events, and she will compete in the 400m, 800m and 1,500m events at the event later this month.

Wheelchair tennis star David Wagner takes the Male Athlete of the Month award after winning four titles in June

The swimmer fought off competition from French Open champion Serena Williams, who finished second, and Briana Rollins, who finished third after setting a new American record in the 100m hurdles with a time of 12.26 seconds, to take the USOC award.

The men's Athlete of the Month award went to Paralympic wheelchair tennis gold, silver, and bronze medallist David Wagner, who went the whole of June without a single defeat, winning four quad titles in the process.

Wagner won all seven of his singles games and all five of his doubles matches, taking the singles and mixed doubles titles at the Japan Open before securing the men's singles and doubles titles at the BNP Paribas Open in Paris, where he defeated world number seven Anders Hard of Sweden in the singles, before teaming up with North American neighbour Adrian Dieleman of Canada to win the doubles title.

He claimed the USOC award ahead of sprinter Tyson Gay in second and swimming star Ryan Lochte in third.

The Bryan Brothers were named as Team of the Month after their first French Open win since 2003

The Bryan Brothers, Bob and Mike, were named as the Team of the Month for June after they also went undefeated on the court throughout the month as they won their 14th Grand Slam men's doubles title at Roland Garros.

The most successful men's doubles team of all-time took their first French Open title since 2003 with their win over France's Michaël Llodra and Nicolas Mahut, before going on to win their 90th doubles title at the Queen's Club in London.

The brothers continued their momentum this month by notching up their third Wimbledon doubles title and their 15th Grand Slam last week, and could be up for the award next month as well as a result.

They fought off competition from the US women's under-16 national basketball team in second and the third placed US collegiate national baseball team to claim the Team of the Month title.

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