[1] Int Testing Agcy, Ave Rhodanie 40B, CH-1007 Lausanne, Switzerland
[2] Manchester Metropolitan Univ, Musculoskeletal Sci & Sports Med, Manchester, Lancs, England
[3] Football Assoc, Football Res Ctr, Burton Upon Trent, England
[4] Orthopaed & Sports Med Hosp, Doha, Qatar
[5] Univ Lausanne, Inst Sport Sci, Lausanne, Switzerland