Sportswear retailer JJB Sports reported a 29% decline in underlying sales and remains cautious about Christmas and New Year trading.The group, which recently appointed DSG International's group retail director Keith Jones as its chief executive, said it expects that trading within the current environment will remain difficult. Like for like sales have shown some improvement since the half year, the group said. August sales were down 37%, September and October were down 27% and November sales declined 21%. "However, like-for-like sales have fallen back to -32% in the first three weeks of December because last year the Sale started on 25 November 2008 and continued to March 2009. This year's sale will start on 26 December and we expect to launch the new Spring ranges before the end of January," the group explained in a company statement.Looking ahead the group added that it does not expect to receive its full stock package until the first quarter of 2010 and as a result is cautious about the upcoming holiday season.