A number of U.S. sporting goods retailers reported fiscal first quarter results last week, showing as a group a 22.9% increase in sales for the period. (see chart on page 5) The four retailers join Big 5 Sporting Goods, which already reported Q1 results, in posting vastly improved comparable store sales results for the period. BGFV comps grew 5.1% in Q1 through March versus a 0.6% gain in the year-ago period. The Sports Authority and Sport Chalet are expected to report this week…