Here is what joker had to say about his own head frame: “I had some ups and downs, and I was really even changing some things in the racket at the start of the year in the tournaments, which was a little bit frustrating me.
“But I managed to find the good rhythm with the racket. It really takes time mentally to accept the change and it’s a big switch. I think it (the Head prototype) has more power. Maybe a little bit too much power in some moments.”
Does that sound like an RA of 51 to you?