One of the interesting developments in research is the use of new technology in investigating issues which would otherwise be very difficult to determine.
Using Virtual Reality (VR) simulations, researchers have been examining how the use of a defensive wall in football when a free kick is being taken may not be as helpful as you might think.
The wall influenced early movement biases, but only for free kicks with curve in the same direction as the required movement; these biases were away from the final ball position, thus hampering performance
The research suggests that placing a defensive wall can reduce the goalie’s ability to stop a free kick from getting in the net. By obscuring the goalie’s vision, there is a delay that is just long enough to hamper the response of even the best goalie.
You can find the paper by Theofilos Ch. Valkanidis ,Cathy M. Craig,Alan Cummins,Joost C. Dessing here : A goalkeeper’s performance in stopping free kicks reduces when the defensive wall blocks their initial view of the ball
Our results cannot suggest an all-out removal of the wall–this study only considered one potential downside–but should motivate goalkeepers to continuously evaluate whether placing a wall is their best option.
The research gives real life examples but also looks, using VR, on the effects of the defensive wall, on the curve of the shot and also recognises that other factors come into play in real life situations….especially when faced with a player who is expert at taking free kicks.