Following Dark Entries' 2013 release School Daze, a collection of experimental recordings Patrick Cowley recorded between 1973 and 1981 that were used as soundtracks to gay pornographic films, the label released a second volume, Muscle Up, in 2015. As with the first collection, this one features extended ambient soundscapes (some of which run past the ten-minute mark) which bear little resemblance to the style of hi-NRG disco that Cowley helped pioneer. However, this set does include an instrumental version of "Somebody to Love Tonight," a percolating midtempo disco number that Cowley co-wrote with Sylvester, one of his most prominent collaborators. The two shortest tracks on the collection, "Pigfoot" and "5oz of Funk," are synth-laden heavy funk cuts that could easily be released as a 7" on Stones Throw. "The Jungle Dream" and "Mockingbird Dream 2" (a longer version of a track included on School Daze) incorporate bird calls and other nature sounds for a sort of cyber-exotica hybrid, and "Timelink" similarly features the droning sounds of a didgeridoo over cosmic synth arpeggios. As with School Daze, the entire album is remarkable, and demonstrates the unlimited potential that the late producer had as a film composer.