The Teessiders have slipped three points adrift of the play-off places as a result of a run of 12 npower Championship games which has brought just two victories.
Youth-team coach Cooper told the Northern Echo: "With the analysis you can do off the field, the answers might not always be there. Sometimes it just doesn't work.
"Before Christmas it didn't look like we would lose a game; now we don't know when we will win again.
"It's hard graft, but I can honestly say that hand on heart. I work with those boys every day. Every single day, they are posing questions, trying to find the answers to turn things around."
Middlesbrough last week