Sportswear retailer JJB Sports has made progress on its three-year turnaround plan, but still posted heavy interim losses and indicated it will need more sales and promotions to keep momentum going.The troubled group lost £24m in the six months to July, down from £42.9m this time last year. Sales rose from £178.6m to £184m.Like-for-like sales have been volatile since the end of the half year, JJB added. In the period from 2 August to 29 August like-for-like sales were up 18%, but fell to 6% in the period from 30 August to 26 September, highlighting how sales are heavily dependent on promotions, it said. "We have consequently taken further steps to drive autumn and peak season sales through increased promotional activity. This is with the continuing strong support of key supplier partners and our bankers, who have agreed that the EBITDAR covenant will not be tested in October to provide us with the flexibility to implement our plans.". Year-to-date like-for-like sales are up 13%."There appears to be increasing caution in the market over discretionary expenditure which means that it is very important to attract customers to our stores with a good range of products, services and prices," added chairman John Clare.