The American, 41, reckons he is still going strong because he has his mother’s genes.
And for the record, Ma Friedel, 70, still works as a PE teacher back home in Cleveland, Ohio.
The Spurs star said: “I was built like my mum, Sue. My dad Len has had a tough go of life when it comes to illness and injury, but my mum has had nothing.
“My dad has got Parkinson’s, has had a stroke, got a defibrillator fitted and a three-pronged pacemaker.
“He has just had a rough go of things from the age of 50. But my mum is still a physical education teacher and has no signs of wanting to stop.
"She is 70 and teaches at an inner-city school from kindergarten — five or six — up to 14 year olds.
“She teaches them all the different sports in the US from volleyball to basketball. If you did not know, you would not know she was 70, that is for certain.”