Lions players got together after a shocking 63-point round four loss against North Melbourne and spoke their minds to get to the bottom of a 1-3 start.
They identified a lack of intensity at training and not playing their on-field roles properly as the problem for the slow start.
Adcock, who plays his 150th game against Carlton on Saturday, said the senior players had to stand up to take the responsibility rather than coach Michael Voss.
Since the player meeting, the Lions have split their last four games, culminating in the season's biggest upset over Essendon last Saturday.
"Maybe since the home truths came out a month ago and training changed a bit and intensity picked up and some on-field roles have been getting done, things have changed," Adcock said.
"It made you think outside of what you're already doing, what you can do better and what you're not doing.
"The senior core definitely had to step up and I think across the board the senior group is having much more of an impact game day."
Adcock was first to put up his hand and say his first month was poor, but like the rest of the Lions, he has slowly found form in the past four weeks.
Fellow co-captain Jonathan Brown played arguably his best game of the season against Essendon, while older heads Andrew Raines, Ash McGrath and Joel Patfull have also been more effective in recent weeks.
Adcock said winning the NAB Cup proved coach Michael Voss had the right gameplan when the players executed it properly – something that was slowly getting done more often in the premiership matches.
"The mood is good, the boys are a bit more upbeat than the last few weeks," he said.
"We know we're now on the right track and moving in the right direction."
They face another big test with Carlton coming to Brisbane on Saturday night.
The Blues inflicted a humbling 91-point loss on the home team last time they played at the Gabba, and Adcock said the Lions' small defenders would have to be wary.
"Eddie's (Betts) not here, so there's one gone. He terrorised us up here last year. Jeffery Garlett's been really good for them this year as well. They've got a really strong and potent forward line when they get going, so you've got to shut them out as best you can."
Michael Whiting covers Brisbane Lions news for AFL.com.au. Follow him on Twitter: @AFL_mikewhiting
