Klose, who celebrates his birthday when Germany take on Portugal in their Euro 2012 Group B opener in Lviv on Saturday, said he was gradually regaining fitness after a thigh injury which ruled him out of action for five weeks.
"I am much further in my fitness now and there is no pain and that is what is important," Klose told reporters, a day after arriving with the team in Poland for the tournament, co-hosted by Ukraine.
"I have got my eye on getting to 100 percent but I don't really think I can reach that figure at my age."
Polish-born Klose, with 63 goals in 116 internationals, is battling with Mario Gomez for the one starting place in coach Joachim Low's 4-2-3-1 formation. Low has also brought Marco Reus into contention for the spot, saying he could also be deployed as an out-and-out striker.
"Mario is super strong and I would also not underestimate Marco but competition is good because it brings life into this business," Klose said, adding that there were no secrets to staying competitive.
"I have no idea. I keep fit, my feet still carry me so I push my cadaver along. I will be 34 so my back hurts occasionally and I do some exercises before and after training. If I do not do them then I am not that fresh or flexible.
"But my attitude is that the last 20 percent you have to pull it out of yourself," he said.
With 14 World Cup goals to his name - one short of Ronaldo's all-time record - Klose is hoping he will stay fit to get a shot at competing at the 2014 tournament.
"I don't know. I take it one step at a time. I will have to see if my legs still carry me," he said.
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