The Ghanaian midfielder spent last season on loan with Real Madrid after being frozen out by Roberto Di Matteo but is now back at Stamford Bridge and looking to make an impact under the returning Jose Mourinho who played him 35 times in Spain last season.
"My style hasn't changed, I'm still the same," Essien said. "You can tell I am still as strong and keeping fit.
"My knees are fine now. My knees are not giving me any problems. I just have to keep myself fit and get ready to do a good job for the team.
"When you have these injuries it's hard to get back but I go with the flow. I don't put pressure on myself or anything. I just listen to the doctors and once I'm fit and training I give everything."