Special Technique

[Pete LSD]

Here is the confusion. I have a friend who consistently break the cross string in the middle of the racquet. Closer inspection of the racquet reveals that several role of cross strings are severely cut in. This is quite abnormal as most string abrasion occurs with the main strings. I am wondering what type of swinging technique will produce this result. I notice the guy holds his racquet with the index finger pointing towards the cone.

[DinkAlot]

That's very weird and definitely swing technique. I exclusively break the main string right smack in the middle. That is, unless I mishit.