Arm swing is key to goalkicking

By Michael Kahn

LONDON (Reuters) - When it comes to successful goalkicking in rugby, it's all in the swing of the arm, British researchers said on Saturday.

Using videos to analyse techniques of professional and semi-professional rugby players, the researchers discovered that the most accurate kickers swing the arm opposite their kicking leg clear across their chest when booting the ball.

The movements are especially exaggerated in players like England's Johnny Wilkinson, considered one of the game's best kickers, said Grant Trewartha, a researcher at Bath University, who led the study published in the journal Sports Biomechanics.

Not every top kicker uses these techniques but those who do are most accurate, especially over long distances, he said. Such players include Scotland's Chris Paterson who so far has a perfect record with 15 out of 15 conversions and penalties in the rugby World Cup in France, Trewartha noted.

"If you watch the World Cup there are people who don't use this technique," Trewartha said. "But it appears to be a key feature of high performance for those that do."

In their study, the researchers analysed video tapes of world class players and data collected from young professional players. They also fitted players with reflective markers to monitor three-dimensional techniques of the kickers.

They entered the information into a computer program that helped identify and measure trends in the techniques, showing that players with the exaggerated arm motion were on average twice as accurate, Trewartha said.

The key seems to be that as the arm swings across the body the motion helps to counteract the movement of the leg, effectively steadying the player and keeping the torso and shoulders facing the target for longer, he added.