And so did some players who could be on their way out of the club in some form or other.
Pascal Struijk and Costinha were among those pictured at the session at the club’s training complex.
Struijk was a regular for Leeds last season and Costinha featured for Olympiacos.
Players undergo a series of physical and medical tests before getting stuck into what will be a demanding summer under the guidance of Fabian Hurzeler and his technical staff.
Zadok Yohanna, the winger brought in from AIK, has been working at Lancing in recent weeks to get up to speed for his new challenge.
He was also involved in the tests and will be keen to make an impact after his £21.5 million move.
Diego Coppola, Amario Cozier-Duberry and Facundo Buonanotte all reported back after loans but could be heading out again for the coming campaign.
It is understood returning loanees Tommy Watson and Eiran Cashin have been working hard at Lancing in recent weeks to get a head-start for pre-season.
Jack Hinshelwood, Georginio Rutter, Matt O'Riley, Danny Welbeck, Olivier Boscagli, Harry Howell, Igor Julio and Charalampos Kostoulas are also among those back at work.
Albion head to France in late July for a training camp plus game against Annecy and Strasbourg behind closed doors.
They then face Roma and Bologna at the Amex ahead of Conference League and Premier League commitments.