Because it is prime and is often seen as a "lucky" number
That would depend based on the League or Association. In the National Basketball Association, there are 12 players that dress for a game which would make 7 reserve players for each game.
There are 11 players on the field, and there can be up to about 18 total players, so there are 7 subs.
In a regulation match, a team must have 7 players in order to start a game.
Professional soccer players typically have shoe sizes ranging from 7 to 12 for men and 5 to 9.5 for women. The average shoe size for male professional soccer players is around 9.5, while for female professional players it is around 7.
Youth team players generally start at a very young age. Players like Neymar started playing at the age of 7. Usually they are 15-17 years of age.
There are 11 players in a Colledge or University team. There might be 7 for younger players.
Fotballers to wear the number 15 jersey are Andrei Arshavin, Footballers to wear 7 are David Beckham, Eric Cantona, Tomas Rosicky, Christiano Ronaldo.
7.
The number of players on a soccer team, any age group, varies. Most people will say about 17-18 is a safe number. You have 11 starting players and 6-7 substitutions. This way if a player is injured, sick, or unable to make a game or tournament there are still enough players to take part in the game. You always want to have at least 3 subs.
Abandon the game. there should be a minimum of 7 players on each team
7 out of 10
You start with 11 players, you must have a minimum of 7 players on at the pitch or the match is ended by the referee.