"Trampled Under Foot" developed from a jam session driven by Jones at the Clavinet. The song went through several arrangement changes before arriving at the version heard on the album, with the group rehearsing various different ideas and arguing about the overall style. Bonham decided the track was too "souly" and rearranged it into a funk style, suggesting that Page should play a guitar riff throughout in place of chords. The lyrics are a series of double entendres around driving and cars. The song quickly became a popular live piece that was played at every live show from 1975 onwards, and was later revived by Plant for his solo tours. It was released as a single in the US on 2 April (with "Black Country Woman" as the B-side) and was a top 40 hit.