When Patrick Vieira throws his arm back at the harrying Neil Redfearn of Charlton, or Ryan Kidd of Preston goes down in a heap in the penalty area after an exchange with Fabian Caballero, we are seeing something that may be not so much to do with individuals following a team's code of behaviour, or with foreign players importing alien habits, as with an involuntary response to the tactical evolution of the worldwide game.
Think about it. The tackle from behind has been outlawed. Tackling from the side, by a defender manoeuvring himself abreast of a forward, is rendered vastly more hazardous by the likelihood that referees, observing Fifa's instruction to punish the slightest hint of illegitimate physical contact, will reward a mis-timed effort with a yellow card - or even, if the offence takes place on the last line of defence, an expulsion. And the speed of the modern forward compounds the defender's problem.
But defenders are there to defend. They have to come up with answers. And one solution, in a close-quarter contest, is a tug of the shirt, or an arm across the chest. Spectators hate it, perhaps because it looks like something any of us could do. Unlike a harsh tackle, even of the Norman Hunter variety, it has nothing to do with skill. Forward and midfield artists hate it even more. Unfortunately for them, they are in a position to do something about it.
In the old days, a defender would hack down a forward and leave him lying on the ground, in no position to react with anything other than a shout of rage or pain. But a forward impeded by a hand or an arm applied to the upper body retains the capacity for physical response. And since the forward is reacting instinctively to a perceived injustice, he may not feel constrained to remain within the rules himself.
"If someone gets hold of you," Howard Wilkinson, the Football Association's technical director, said this week, "the only way to get free is to use your arms and elbows. You've only got to watch a boxer in a clinch to see that. What can be a movement to break away can look like striking out." He paused, then added: "And those predisposed to striking out will see it as a bit of an excuse."
Not everyone sees it as an urgent new problem. "It was always there," Roy McFarland, the distinguished former England centre-back, told me. "But now, thanks to television, you see things you didn't see before. The technology has improved the spectators' position, if you like."
But McFarland, now managing Cambridge United, agreed that the defender's job has become much more demanding. "They have to be 100 per cent right when they're trying to make a tackle, rather than just 60 or 70 per cent right. So maybe they're trying to get themselves into the right position, and tugging or pulling to get there. In my day it didn't matter so much. If we couldn't manage to intercept the ball, we could still go in from behind and kick the forward. Oh yes, make no mistake about that. We got away with murder."
The suggestion that shirts were always tugged finds a supporter in Ray Wilkins. "You just see it more clearly now," the former England midfielder said, "especially in the Premier League, where TV examines every incident from so many different angles. Most of the time you'll find that both parties are doing the tugging or shoving." Yet today's defenders, he continued, are "petrified to hit anybody from the side or from the back - the good thing is that they're now staying on their feet and not going to the ground, which is an aspect of their craft that should be highlighted anyway."
For Howard Wilkinson, the change in the laws is forcing defenders to learn to apply greater skill and judgement. "I think we're moving into a period where people are becoming very aware of that," he said. "What the new rule on tackling did was cause defenders to defend very deep rather than push up and get close to their opponents. The analysis of the last World Cup supports that view. Instead of only having to make a decision about whether to get in front of the forward and pinch the ball or stay on their feet and tackle him, they've chosen to drop off and defend the 18-yard line."
The effect of this, he pointed out, is to reverse the trend of the 1970s and '80s, when the game became artificially compressed in midfield. "The game has got very stretched again," he said. "It's become much more difficult for coaches to compress the game."
It is also more demanding on the players. "You can't go out with just a general pressing game. You have to decide, are we going to press early? If we aren't, when are we going to press? So the responsibility has gone much more back to the players. Defenders have to be more able to make decisions, and their choices have to be much more educated. It's the whole business of when to tackle and where. 'Can I get alongside, can I get in front, can I get my foot across?' Individual defending is something people are going to be paying attention to, as much as to individual attacking."
Roy McFarland took up a point made recently by Joe Kinnear, the Wimbledon manager, that coaches have to teach defenders to intercept passes rather that make challenges. "That's dead right. In my day the better player would always be looking to intercept the ball. I was lucky enough to play with Dave Mackay, Bobby Moore and Colin Todd, who were all exceptional readers of the game. What is the forward going to do with the ball? If you can read that accurately, you can get in position to pinch the ball without having to make a tackle. That was the skill. And that side of it has to be so much better today, because defenders are worried about chasing forwards."
When the opponent is a real speedster, an Overmars or an Owen, the problem is even more acute. "And in the Premier League it isn't just isolated players with pace," McFarland said. "There's pace throughout every team. That means the game has opened out, it's more end to end. I've got three very quick forwards here at Cambridge, and I tell them that if they've got half a yard on a defender, to keep going."
"Look at the pitches," Ray Wilkins remarked. "They're bowling greens. There's no mud. Five or 10 years ago, half the pitches would have been mud patches at this time of year. And that's conducive to pace."
These changes, and others, have put unprecedented demands on the ability of defenders to concentrate throughout a match. "You can't knock the ball back to the goalkeeper and take a breather any more," McFarland pointed out. "When you do pass back, you have to be looking for a return pass from the goalkeeper if he's under pressure. The ball's in play the whole time. And allowing players to come back from offside positions, that's made a big change, because you can't push up and catch forwards offside so easily."
And to those who value the game's creative arts, the changes have brought a further bonus. "You see a lot more freedom and space in the middle of the park," Howard Wilkinson pointed out, "and the players who've come into their own are people like Bergkamp and Zola and Zidane, who've exploited that space - people who can not only pass the ball but run with it as well. The perception of the midfield general has changed. You used to need someone who could put his foot on the ball and calm the game down, but now he's not so much of a sitter and a sprayer. He's playing further up the field. Looking at players from the past who would have benefited, you might think of Michel Platini. And you have to wonder how good Kenny Dalglish would have been in this environment."
It is, as Wilkinson observed, hard to find a genuinely sterile game these days. "It's making the game more imaginative," Ray Wilkins agreed. McFarland was similarly optimistic. "Think of the way Wimbledon used to squeeze teams," he said. "It was boring, negative and hard to play against. And those days have gone." Seen in that light, squabbles over who elbowed whom may be no more than a minor distraction.