One way to add conditioning to a training session is to simply add intensity. Below is a 6 v 4 plus keepers protect the lead game that lasts 8 minutes and done at full speed has a lot of fitness work built in.
This game uses a half field and has a goal on each end line and a keeper in each goal. There are four midfielders and two forwards on one team and four backs on the other team.
The ball always starts with the attacking teams keeper so any dead ball results in the ball starting with the attacking keeper.
As long as the score stays 1-0 for the defending team, they can afford to sit back and defend and keep the ball in front of them. The attacking team has to play quickly. If the score gets tied up, the defending team will have to start more aggressively which will result in them using even more energy.
When the ball goes out of play, the attacking keeper would rush to get a new ball and the field players would sprint to get into position (the attackers to position themselves for the next attack and the defenders would rush to get back into position to be behind the ball).
Play this game for 8 minutes and then give a 1 minute break and then start up again with new defenders (everyone should get experience being up a goal as well as down a goal. If you play this a total of 3 times it’s great fitness while working on a tactically important game situation.
Have a great day!