Ainley, who turns 37 in July, is back locking the scrum for the Highlanders after some calf issues got his season off to a slow start.
He said the game was getting more combative and competitive but that was just the way the game had headed.
''That just comes with professionalism. You get the bigger guys, training longer and harder, they will be bigger, they will be faster and will be more competitive,'' he said.
''As the game grows, the boys get paid more and there is more competition for those spots and you have to play harder and faster.
''I was always a loose forward. I would not still be here if I was still a loose forward. I have moved into the second row. I think everybody has to change their game. The rules change every year and you have to adapt to that and that changes your role.''
He said the bangs still hurt but they hurt no matter the age.
''But it is about a want, about a desire. If you want to play the next week, you do the recovery and do your best to get over it.
''It is the same as any job. If you do not want to be there, then you shouldn't be there. I'm still loving my footy and I want to be there.''
Ainley, who joined the Highlanders in 2015 after a career that took him to Japan and Europe and a stint with the Tasman Makos, had signed one-year deals with the franchise every year.
His former team-mate Shane Christie announced his retirement on Monday from concussion and Ainley said he was happy Christie - who was a good friend of his - had made the decision to hang up the boots.
''He has not played for a couple of years. I do not wish that on anyone ... I don't want him coming back and get hurt again.''
Ainley said there was always someone new coming along. Shannon Frizell looked the next cab off the rank in the Highlanders stocks and was impressing his fellow forward.
''He is a freak; got the skills and the speed and the size. He's only a young boy, still reading the game. They said he was on the All Blacks' radar and so he should be. He does not say much but he can go a long way.''