 "Jack Your Body" was also the first UK number one single to achieve the majority of its sales on the 12" format.Under the chart rules in place at the time, the 12" sales should not have counted toward the song's chart position, as its running time exceeded the then-current 25-minute limit.However, the 25-minute rule was not enforced, since the running time was not brought to the chart compilers' attention until the record was already at number one.