Sledging; a term used to describe the practice whereby players seek to gain an advantage by either insulting or verbally intimidating the opposing player.
This weekend's Premier League action provided two examples of 'penalty sledging' - each with contrasting outcomes - as Manchester City goalkeeper Joe Hart won the battle of the brains at the Liberty Stadium at the expense of Swansea striker Scott Sinclair, before Manchester United striker Wayne Rooney emphatically slammed past former teammate and West Brom stopper Ben Foster at Old Trafford.
The purpose of 'sledging' is to try to weaken the opponent's concentration, in an attempt to cause them to make a mistake or underperform - which begs the question whether such tactics constitute poor sportsmanship or good-humoured banter - is it fair, or foul play?
In ethics, sporting or otherwise, the concept of fairness involves treating everyone equally and impartially. 'Fair play' is usually understood to mean using only tactics that are in accord with the spirit of the sport.
Other sports sometimes have their own terminology for sledging: in basketball it is known as 'trash talk', while in ice hockey they call it 'chirping', and is widely accepted as part and parcel of their respective games. Football is not traditionally known for its sledging, despite the obvious on-the-field confrontations that exist in all levels of the game.
Some players use dubious, but ultimately legal tactics - such as distracting an opponent in a penalty situation, to gain an extra advantage. Others may try to fool their opposition by misrepresenting their own skill level, in order to make their rival overestimate, or underestimate them.
The practice known as gamesmanship appears to be a dying art, but while not usually explicit to the rules of any given sport, is an ethical practice that must continue to be adhered to for the good of the game.
All sports come with their own set of rules and conventions, and as such there will always be an opportunity for participants to cheat. Whether or not the 'mental disintegration' of players and/or goalkeepers in a spot-kick situation should be regarded as breaking the rules is still up for debate.
Joe Hart ended up on the losing side as Manchester City fell to a 1-0 defeat at Swansea, so his vital save and more specifically the pre-penalty conduct that arguably led to it, almost pales into insignificance.
Meanwhile, Manchester United capitalised on their title rivals slip-up, with a 2-0 win over the Baggies. The hosts already had the advantage when Rooney doubled the lead from 12-yards. The fact that he scored suggests that Foster's sledging was ineffective - but it still shouldn't be forgotten.
Upon his penalty conversion, the England international striker was seen staring ominously back at the West Brom goalkeeper, but later posted on Twitter that the incident was all in jest.
"I looked at Ben Foster after pen because I took a lot of pens against him in training and before I took [the] penalty he tried to put me off," he explained.
"Ben Foster is a good friend of mine. Top lad."
Whether you agree with it or not, one thing that can't be argued is that penalty sledging is on the rise. Some incidents intimidate, others are tongue in cheek. But they each show that football, like all sports, is as much a game of mental strength as it is physical.