four years, the world championships are held every year. There are 22 world championship's events and only 14 Olympic events. In Olympic years, the Games serve as the world championships for those 14 events, while the other eight events have their own world championships held in conjunction with the Junior World Championships. Athletes on the Senior National Teams are chosen from both a selection camp and trials process, depending on the boat category. USRowing's Under 23 National Team competes at the World Rowing Under 23 Championships each year. This developmental team has placed numerous athletes on the world championships and Olympic squads. Athletes on the Under 23 squad are chosen from both a selection camp and trials process, depending on the boat category. USRowing also fields a Junior National Team that competes at the World Rowing Junior Championships each year. Junior national team athletes are chosen from both a selection camp and trials process, depending on the boat category. Events USRowing hosts five national championships regattas – USRowing Indoor National Championships, USRowing Summer National Championships, USRowing Summer Youth National Championships, USRowing Youth National Championships and USRowing Masters National Championships. In addition, USRowing hosts national team selection events for the Senior, Under 23 and Junior National Teams. USRowing also hosts several regional regattas for youth and masters athletes. In addition, USRowing hosts several national team selection events each year. The National Selection Regattas are the initial step in the senior national team selection process. USRowing also holds National Team Trials to select certain boat categories for the Junior, Under 23 and Senior National Teams. Classifications and masters handicaps In the "Rules of Rowing," USRowing sets classifications for competitors by age, skill, and sets handicaps by age for masters rowers. Classifications by skill include: Elite: National Team athletes or medalists at the World Rowing U23 Championships Senior: Non-elite rowers who have won in the Intermediate or Senior category at the USRowing National Championships or Royal Canadian Henley Regatta Intermediate: Athletes who are not Senior or Elite USRowing classifications by age are based on the calendar year in which an athlete's birthday occurs for a given category. So for the U19 category, the athlete may compete in the category until December 31 of the year of their 18th birthday. The Rules of Rowing contain categories for U23, U21, U19, U17, and U15. Athletes may compete in "youth" categories until the year they turn