age group; the junior leagues in the United States generally operate as fully amateur teams to maintain the players' eligibility to play in college. Lower-end minor leagues and more obscure sports often operate at a semi-professional level due to cost concerns. Because the cost of running a fully professional American football team is prohibitive, semi-pro football is common at the adult levels, particularly in the indoor variety, providing an outlet for players who have used up their NCAA eligibility and have no further use for maintaining amateur status; as a sport that normally plays only one game per week, American football is especially suited for semi-pro play. The National Lacrosse League, whose teams also typically play only one game per week, pays a salary that is enough to be considered fully professional, but players also are able to pursue outside employment to supplement their income. The lowest levels of organized baseball are also effectively semi-professional, as the short summer seasons and low salaries require players to hold jobs in the offseason to make ends meet. United Kingdom of Great Britain and Northern Ireland There are several hundred semi-professional football teams at non-League level. The bottom division of the English Football League (the fourth tier of the English football league system) has traditionally been the cut-off point between professional ("full-time") and semi-professional ("part-time") in English football. However, many teams in the top non-League competition, the National League, have become "full-time" professional clubs in an effort to achieve League status. Many former League clubs also remain as fully professional teams following relegation to the lower leagues at least for as long as they retain a large enough average attendance to generate the income needed to pay the players. Women's football in England is semi-professional at the top levels, as finances depend on promotion and relegation both of parent male teams and of the female teams themselves. Full professionalism for women is still in the planning stages; top female players often depend on other sources of income (such as coaching and physical training), and many attend university or college while playing. In Scottish football, semi-professional teams compete at all levels below the Scottish Premiership, with most teams below the second-level Scottish Championship being semi-professional. Historically, English rugby league and rugby union have had one full-time professional division, with semi-professional divisions at the next level down. The second tier of union, the RFU Championship,