Coleman was left out of the squad for Ireland's opening two qualifying games, manager Heimir Hallgrimsson citing his lack of game time at club level.
The 37-year-old has started all four matches since then, despite playing only 12 minutes in the Premier League this season.
"Everyone wants to be playing, that's the way it works," vice-captain Coleman told reporters in Prague ahead of Thursday's game.
"I didn't have many minutes before the last games, but I train 100% every single day. Sometimes to my own detriment, maybe sometimes I go too hard and it's cost me at times, but it's the only way I know.
"When you put on the green shirt and when everything's at stake, I'm feeling good and I'm ready for the game."
Ireland began their campaign collecting one point from three games, but turned things around with three consecutive wins and that is what the team are focussing on rather than previous play-off defeats for the 2010 and 2018 World Cups.
"Obviously the nation was hurt massively," Coleman said.
"But in terms of the current group of players, they're all so young, I don't think they're dwelling too much on that hurt.
"We're just riding the wave of the confidence we've got as a group, which I think this young group deserves after the last two games. To see how the nation is feeling now is incredible, and we've got a duty to try and make them even happier."
Parrott's play-off push
A play-off spot seemed almost impossible as Ireland went into their final two group games needing wins against Portugal and Hungary.
Troy Parrott scored all five goals in those victories, including a hat-trick in Budapest, where a 96th-minute winner booked their play-off place.
Thousands of Irish fans have made the trip to Prague, most without tickets, and Coleman would dearly love to give them even more to celebrate.
"Selfishly, it would be amazing because as players, you do want to do as much as you can in the game," Coleman said.
"But to be honest, after the aftermath of the last two games, seeing what it did to our country was incredible, how it lifted our people, how it genuinely made people happier and gave people something to talk about.
"Myself and all the players, as much as we want to do it for ourselves, the manager, and all the staff, we do want to do it for the people of our country as well."
The winner of Thursday's game will host either Denmark or North Macedonia in Tuesday's final.