(ShareCast News) - Shares in Sports Direct International surged on Friday, with traders attributing the push higher to short-covering ahead of the stock's demotion to the FTSE 250 next week.The retailer has been under the cosh since late last year, when it was hit by a damning report in the Guardian about its pay and treatment of staff, while a profit warning in January caused the shares to tank.More recently, the company's boss Mike Ashley was made to appear before a commons select committee to be questioned over Sports Direct's use of zero-hour contracts and allegations about harsh conditions imposed on its warehouse staff.Ashley invited MPs to visit his Derbyshire warehouse facility, but they rejected the offer on the basis that it was not in line with its "commitment to transparency" - a clear snub to the Newcastle Football Club owner.Shares in the company were up 7.9% to 433.20p at 1250 GMT. However, the shares have put in a dismal performance year-to-date, down 25%.Volumes traded were just over 1.6m on Friday versus the 30-day average of just under 2m.