0 0 ▁metres ▁has ▁been ▁raised ▁from ▁ 4 5 ▁to ▁ 5 2   km / h . ▁Similar ▁speed ▁increases ▁are ▁shown ▁in ▁the ▁other ▁distances . ▁ ▁Professional ism ▁After ▁the ▁ 1 9 7 2 ▁season , ▁European ▁long ▁track ▁sk aters ▁founded ▁a ▁professional ▁league , ▁International ▁Speed sk ating ▁League , ▁which ▁included ▁Ar d ▁Sch enk , ▁three - time ▁Olympic ▁gold ▁med all ist ▁in ▁ 1 9 7 2 , ▁as ▁well ▁as ▁five ▁Norweg ians , ▁four ▁other ▁Dutch men , ▁three ▁Sw edes , ▁and ▁a ▁few ▁other ▁sk aters . ▁Jon ny ▁Nil sson , ▁ 1 9 6 3 ▁world ▁champion ▁and ▁Olympic ▁gold ▁med all ist , ▁was ▁the ▁driving ▁force ▁behind ▁the ▁league , ▁which ▁fol ded ▁in ▁ 1 9 7 4 ▁for ▁economic ▁reasons , ▁and ▁the ▁IS U ▁also ▁ex cluded ▁tracks ▁hosting ▁professional ▁races ▁from ▁future ▁international ▁champion ships . ▁The ▁IS U ▁later ▁organ ised ▁its ▁own ▁World ▁Cup ▁circuit ▁with ▁mon et ary ▁pri zes , ▁and ▁full - time ▁professional ▁teams ▁developed ▁in ▁the ▁Netherlands ▁during ▁the ▁ 1 9 9 0 s , ▁which ▁led ▁them ▁to ▁a ▁domin ance ▁on ▁the ▁men ' s ▁side ▁only ▁challeng ed ▁by ▁Japanese ▁ 5 0 0   m ▁rac ers ▁and ▁American ▁inline ▁sk aters ▁who ▁changed ▁to ▁long ▁tracks ▁to ▁win ▁Olympic ▁gold . ▁ ▁North ▁American ▁profession als ▁During ▁the ▁ 2 0 th ▁century , ▁roll er ▁sk