Tag
Tactics
The side of the pitch where the ball is. When defending, you want more players ball side than away from it, since that's where the danger is. "Getting ball side" means positioning yourself between your opponent and the ball. Defenders who stay ball side cut off passing lanes; those who get caught wrong side get played in behind and face danger from fast attackers.
The first thing coaches teach young defenders is to stay ball side. If you're marking a striker and the ball is on the right, you need to be between that striker and the ball, not standing goal side waiting.
Running the channels means running into the space between a centre-back and full-back. That gap is the "channel." Attackers who time runs into the channel are hard to track because neither defender wants to leave their position. A good channel run, combined with a good through ball, is one of football's most effective attacking combinations. Strikers who make these runs constantly stretch defences.
Jamie Vardy's runs into the channel were legendary during Leicester's journey to the title in 2016. He'd drift wide, spot the gap between centre-back and full-back, and sprint into it. The defenders were never sure who was supposed to follow him.