Junior footballers are being discouraged from copying Premier League superstars like Jack Grealish by wearing mini – or micro – shin pads. The 28-year-old Manchester City winger is among the players to have made famous the minuscule shin guards that are little more than the size of a train ticket. Why some professional footballers have taken to wearing the miniature pads – together with low or ankle socks – has been the subject of considerable debate during the last season. While Jack himself, in a GQ interview, was quoted as saying it is ‘just something I’ve always done’. But with the trend n…