Trainers and tracksuits chain JD Sports Fashion has witnessed an improvement in sales growth during the eight weeks to 5 June.Cumulative UK and Ireland like for like retail sales growth of 4.1% was more than twice the 2% rise reported for the 10 weeks ended 10 April.World Cup fever aided a "satisfactory" performance at the Sports business where like for like sales rose 5.1%, although the Fashion fascias fell 1.2%.There'll be a further update with the interim results on 21 September.