JJB Sports says it is likely to breach its banking covenants as sales continue to fall short of expectations at the sports shop chain.Trading conditions have been "extremely challenging" since it last updated the market early last month and the company thinks this has been exacerbated by the current bad weather.'At this stage, with two months of important trading remaining before the year end, covering the pre-Christmas and New Year sale periods, the outlook for the full year remains uncertain,' the company said.The tough trading conditions mean that JJB "now believes that it is likely that it will breach certain financial covenants in the £25m revolving facility provided by Bank of Scotland ("BoS") when they are next tested at the end of January 2011."Last month JJB reported that an autumn promotional drive failed to juice up sales. Excluding value added tax, like for like (LFL) sales for the period from 2 August 2010 to 7 November were up 11.5% on the corresponding period of last year. That's below the rate achieved in the year to date (YTD). Year to date LFL sales are up 13.4% compared to the equivalent period last year, a slight improvement on the 13% YTD rise the company reported at the end of September. Its fortunes are in contrast to the trendy sportswear retailer JD Sports Fashion, which is continuing to see sales rise.