For centuries,the humble handshake has been the respectful greeting practised all over the world. But,now it seems that Britain is waving goodbye to the tradition which dates back to the Middle Ages. A new research by Manchester Metropolitan University has revealed that many young adults now consider shaking hands too stuffy and instead prefer to give either a casual wave,an air kiss or even a street-savvy fist bump. Almost three quarters (74 per cent) of British adults have admitted they no longer reach out a hand to greet friends and colleagues. While 69 per cent of the over-25s still use the handshake,only 45 per cent of the under-25s do the same. In fact,modern youngsters now prefer the touching of clenched fists,a hug or a showbiz-style air kiss. According to the research,based on a survey by hand wash manufacturers Carex,many opt for no physical contact at all because of fears about hygiene. From the poll of some 1000 adults,67 per cent revealed that health fears played a part in their reluctance to shake somebody's hand. "In our evolutionary past,touch was the foundation of families and civilised coexistence,helping to reduce stress,violence and dissent. As a type of ritualised touching,the handshake is one of the few forms of public physical contact that still survives today," said lead researcher Dr David Holmes. The handshake is believed to have been born when medieval knights would display an open hand to each other to demonstrate they were not carrying a weapon.