There's low tensions, and then there's Mikhail Kukushkin's frame. (Tecnifbre)

Delray Beach, FL. — Tecnifibre is the official stringing service of the ATP 250 event in Delray Beach, and they've had a busy week so far. On Monday, they strung 80 frames on a day that saw just five singles and two doubles matches.

It takes the Delray Beach Open professional stringers just 12 minutes per racquet (including the stenciling and packaging). The most demanding customers are Juan Martin Del Potro, Jack Sock and Milos Raonic with five frames per match.

While that makes sense, the tension highs and lows of the week could come as a bit of a shock.

"Jack Sock is very low, and Dustin Brown is very high. [Mikhail] Kukushkin is very low also," Delray Beach Open stringer Jay Lewandowski said. "It depends on their stroke and their racquet, and its weight and balance. Everybody is a little bit different, it's all sort of a personal preference."

Alexandre Papineau, Tecnifibre's marketing manager, said that ninety percent of the players get their frames strung between 45 and 55 pounds.

But Brown asks for 79 pounds, while Kukushkin gets his frames at 32 pounds. Yes, that's right, 32 pounds.

"Some players want to have the pocket effect," Lewandowski said. "They want the ball to pocket onto their strings. They have a very lively arm so they want to have more feel."