New signing Dominic Solanke took part in the session but club-record signing Mohamed Salah was notable by his absence.
The likes of Philippe Coutinho, Emre Can and Dejan Lovren were not in attendance as they have all been given extended breaks by the club.
Lazar Markovic and Mamadou Sakho could be seen being put through their paces on exercise bikes following their respective loan spells last season.
The Anfield-based side start their pre-seaon in earnest on July 12 with a friendly against Tranmere Rovers.
Check out some photos of the session in the links below.
It's good to be back!
— Liverpool FC (@LFC) 5 de julho de 2017
View the full gallery as the Reds return to Melwood: https://t.co/EGBiQGpVQh pic.twitter.com/TkpoK3mOS0
A busy first day back!
— Liverpool FC (@LFC) 5 de julho de 2017
More photos from Melwood: https://t.co/57p8mTMoUB pic.twitter.com/dI7D522Kxv
@Nathaniel_Clyne
— Liverpool FC (@LFC) 5 de julho de 2017
More: https://t.co/jJEsXTsIQ5 pic.twitter.com/qghWqrjbZK