Question: The star of the film "What Happened to Jones" was once a champion in what amateur sport?

Context paragraphs:
Germany Olympic football team: The Germany Olympic football team represents Germany in international football competitions in Olympic Games.  It has been active since 1908, and first competed in 1912.  Olympic football was originally an amateur sport, and as the pre-World War II German national team was also amateur, it was able to send a full national team to the games.  After the war, Germany was divided, but until 1964 East and West competed under the name of "United Team of Germany", although without a combined squad.  From 1968 West Germany began to compete on its own, but were still forced to send an amateur team, who were not able to match the success of their professional counterparts in the World Cup and European Championship.  The rules on amateurism were relaxed in the 1980s, which allowed West Germany some success, notably a bronze medal finish in 1988.  Since 1992 the tournament has been competed by under-23 teams, making Germany's Olympic qualification dependent on the results of the under-21 team.  Only in 2016 the Germans returned to the Olympic stage, with a silver medal after losing on a penalty shoot-out to hosts Brazil.  Reunified Germany is now the only World Cup champion without the Olympic gold.

Sport in Croatia: Sport in Croatia has significant role in Croatian culture, and many local sports clubs as well as the Croatian national squads enjoy strong followings in the country.  The most enduring sport by far in Croatia is football, and is played on amateur and professional levels amongst all age groups across the entire country.  Several other major team sports are handball, basketball and water polo, with clubs in all parts of Croatia.  Ice hockey is another popular team sport, namely in the Croatian interior.  The most popular individual sports in Croatia are tennis, alpine skiing, and swimming, and to some extent table tennis and chess.  Various amateur sport games are popular in Croatia, notably picigin.

Hellenic Amateur Athletic Association: The Hellenic Association of Amateur Athletics (Greek: Σύνδεσμος Ελληνικών Γυμναστικών Αθλητικών Σωματείων ; abbreviated SEGAS) is Greece's governing body for amateur sport.

Sports associations (East Germany): The term Sports Associations (German: "Sportvereinigung" , ] ) in East Germany (German Democratic Republic, GDR) meant a sports agency for certain economic branches of the whole society, which were members of the East German Sports Association (DTSB).  Members of biggest social employers had their own branch sports clubs or the "Sportvereinigung".  One of the biggest problems is that you can not find almanacs of these today.  All of them were recycled or sold to private persons.  So you can not start an article about each trade sports association, since 2012.  The rest are data banks of history sections from the sport club sites with the certain name or in addition: pennants, medals, flags, and other related objects.  Nevertheless, you can find still a lot of sports societies in the former GDR which use the old names.  After 1954 they separated amateur sport from professional sport, and from 1961, most Trade Sports-Associations of sports societies in the GDR had been closed but existed under single clubs with the name BSG ("Betriebssportgemeinschaft") which meant Cooperative Sports Collective in English.  In 1966, the football sections were separated and they used the name Fußballclub (FC).  They had to conform to the rules of the East German Sports Association.  The sections of the associations were called Sports Clubs (SCs) for only the professional athletes.

Canadian Superbike Championship: The Mopar Canadian Superbike Championship (CSBK) is the leading road racing superbike championship in Canada.  The championship is managed and organised by Frontline CSBK Inc.  The series operates in the summer months, normally between May and August and includes classes for Pro Superbike, Pro Sport Bike, Amateur Superbike, and Amateur Sport Bike.

Ellen Brockhöft: Ellen Brockhöft, née Rehra, (29 April 1893 – 19 December 1977) was a German figure skater.  Competing in ladies' singles, she was a two-time World silver medalist and a seven-time German national champion.  She represented Germany at the 1928 Winter Olympics and finished ninth.  Brockhöft was a member of Berliner Schlittschuhclub.  During her skating career she claimed to be younger than her real age, believing this would help her career.  She retired from amateur sport in 1929 and became a coach in St. Moritz.

What Happened to Jones: What Happened to Jones is a 1926 silent film comedy directed by William A. Seiter and starring Reginald Denny.  It was produced and distributed by Universal Pictures.  The film is taken from an 1897 Broadway play, "What Happened to Jones" by George Broadhurst.

Reginald Denny (actor): Reginald Denny (born Reginald Leigh Dugmore, 20 November 1891 – 16 June 1967) was an English stage, film and television actor as well as an aviator and UAV pioneer.  He was once an amateur boxing champion of Great Britain.

Sport in Milton Keynes: Sport in Milton Keynes covers a range of professional and amateur sport in the Borough of Milton Keynes.  There are professional teams in football (MK Dons), in motorsport (Red Bull Racing ) and in ice hockey (MK Lightning).  The National Badminton Centre, and the Marshall Milton Keynes Athletic Club train professional and amateur athletes.  Most other sports feature at amateur level although there are semi-professional teams in rugby union and football among other sports.  There is an international-standard karting track owned by Daytona Motorsport.

List of French football champions: The French football champions are the winners of the highest league of football in France, Ligue 1.  Since the National Council of the French Football Federation voted in support of professionalism in French football in 1930, the professional football championship of France has been contested through Ligue 1, formerly known as Division 1 from 1933–2002.  Prior to this, the first division championship of French football was contested through a league ran by the Union des Sociétés Françaises de Sports Athlétiques (USFSA), an organization that supported amateur sport.  The USFSA's league ran from 1894–1919 and awarded 22 league titles before being suspended in 1915 due to World War I and the creation and success of the Coupe de France, which had quickly become the country's national competition.  The USFSA returned in 1919 changing the league into numerous regional amateur leagues that awarded no league title.  This system lasted from 1919–1926.  In 1926, the first division's reigns were handed over to the French Football Federation.  The federation organized and ran a league composed of the regional amateur league champions called the Championnat de France amateur from 1927–1929 and awarded three titles before the league was converted to the professional league that exists today in 1932.

Supporting paragraphs: What Happened to Jones Reginald Denny (actor)
Answer: boxing