An overlap or underlap is a forward run performed to achieve either of the following:
The difference between the overlap and the underlap lies in the path of the run in relation to the ball-carrier.
An overlapping player commits the run on the outside of the ball-carrier and therewith in a wide area.
An underlapping player commits the run on the inside of the ball-carrier and therewith in a more central area
Here's an example of overlapping and underlapping and where it can force the defender into moving.
As either of these runs need space to run into, they usually take place in wide areas. The most common pattern is a full back either overlapping or underlapping a winger to create 2v1 opportunities to cross the ball. It is the decision of the ball carrier as to whether they pass to the runner or use them as a decoy to exploit spaces that the run has created.
The attacking team would need to be in good possession of the ball in order for a player to consider making a forward run. The runner, whichever position they play, would likely leave their own position to try and create/exploit space so there is a risk of the team becoming unbalanced if the team do not have good control of the ball.
You might also see these runs when a team is on the counterattack in a 2v1 or 3v2 situation. In these scenarios a defender might cut off a passing lane to isolate the ball carrier in a 1v1 situation. An overlap or underlap might help overcome this scenario.
It’s often the full back that tends to make an overlapping run, and either a midfielder or full back that make underlaps the ball carrier to try and get into the half space.
Firstly, these players would need to be physically capable of making forward runs at speed AND recovering back into position quickly. The role of an overlapping full back is an extremely physically demanding role and involves lots of high-speed running.
This player would also have good game intelligence, an understanding of when and when not to make a forward run. Equally, they understand that in making these runs they may not even receive the ball but their run has created space for their teammates to exploit.
Technically, they would be good crossers of the ball and be composed to make good decisions in the final third of the pitch.
The key coaching points:
Recognition: Identify 2 v 1 opportunities
End product: Shot, Cross (back post, behind defenders, pull back), dribble
We have some example practices that you can use and adapt with your team to work on overlapping and underlapping to create space for goalscoring opportunities.