Weekend tennis injury threat

Keen amateur tennis players trying to copy the styles of top players risk serious injury in the process.

Modern professional players have adapted their styles so that they can hit the ball harder with lighter racquets.

However, experts warn that their techniques could place far too much strain on less fit shoulders and backs.

Players such as Andre Agassi and Venus Williams have adopted a more open stance on their forehands - with their feet facing the net.

This means that their upper bodies rotate to generate extra power and spin.

However, this extra rotation requires a high level of upper body fitness and flexibility to cope.

Professional players also time and execute their strokes better - failure to do so increases yet further the strain on the body.

Karin Grabcova, from the University of Greenwich in London, said: "The situation is worse for amateur players who are mimicking this open-stance, pioneered by the professionals - as they have neither the body strength, fitness levels or skill of the professionals to cope with this more punishing technique.

"In laboratory trials we were able to discover how effective the open and closed stance forehand techniques are, and measure the strains placed on the body."

Basic, simple strokes

A sports science expert from Sheffield Hallam University told BBC News Online that there was no substitute for amateur - and professional players - being coached well in basic, simple strokes.

Professor Roger Bartlett said: "This isn't just a problem among amateurs, but also among professional sportsmen at all levels.

"You don't just get an 11 year old schoolboy trying to copy the style of javelin thrower Jan Zelezny - you get people like Steve Backley (an Olympic gold-medal holder) trying to do it.

"Neither of them can, because neither of them have Jan Zelezny's body."