Albion boss Dean Wilkins has warned his players to grow up and get tough.
The Seagulls were brushed aside by play-off candidates Oldham in the final home game of the season.
They are safe from relegation but only because Bradford lost at Chesterfield.
Wilkins admitted: "Over the summer there is some serious growing up to be done.
"Sean Gregan (Oldham defender), with all his experience, bullied some of our players.
"He smashed in with his elbows, probably not deliberately but Alex Revell ended up on the floor and we had the trainer on twice.
"I am not advocating that we come back in the summer and start smashing people to bits but we have got to learn fast over the next eight to 12 weeks about how to look after ourselves.
"Especially at home, when sometimes teams are dropping deep, we have got to have a far greater physical presence when we are putting balls in the box.
"Over the summer everyone is going to be given a strength and conditioning programme to try and improve that aspect."
First half goals by Chris Porter and Andy Liddell clinched a precious first victory in six games for Oldham and sentenced the Seagulls to a fifth straight defeat.
Dean Cox replied late on with a spectacular strike but Albion have finished the season at Withdean with a hat-trick of defeats and just two points out of 18.
Wilkins said: "It's painful. I know how much supporters want to see us score goals at home and win.
"We need to see an improvement."
l Albion under-18s beat Northampton 3-1 in the South East conference with goals from Sonny Cobbs, Sam Gargan and Matt Foreman.
Crawley Town got the point they needed to be sure of Conference survival following a goalless draw with Kidderminster at the Broadfield Stadium.
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