Updated: Feb 10
If you're playing advanced competitive tennis these days you've likely come to understand that you must be using polyester string in some form to actually be competitive. In the late stages of his career, as polyester string was just becoming prevalent on the pro tour, Pete Sampras referred to the new Luxilon brand polyester as "Cheat-ilon". It was clear to Sampras that the ball was being made to bend, dip and explode off the court with power and spin as never before and it was becoming more difficult to play his all-court game. He was concerned. Tennis hasn't been the same game at the tour level since.
The advantages of polyester string are significant. Massive amounts of spin can be generated, making it possible for players to swing as hard as they can without fear of hitting out. It allows power to dictate the game like never before. It's a sharp distinction from prior years when the emphasis leaned toward control and placement. It truly has changed the strategic approach.
Unfortunately, the disadvantages of polyester string are also clear. It's stiff. It's so stiff that the ball itself compresses against the string-bed as it would against a brick wall. That's different from natural gut for example, which is very elastic and allows the ball to retain most of its shape as it impacts the string-bed. Combined with ever stiffer frames, polyester string has proven to pose a serious physical risk. Its stiffness is the key to its effectiveness however and though softer "more comfortable" versions of polyester are available, consequently they lack the spin potential of the stiffer ones. How to maintain all of the best performance qualities of the stiffest polyesters while protecting players from injury is the ultimate riddle to be solved.
That's where the BOLT Zipstrip comes in. Its design addresses precisely this dilemma. In a BOLT most of the strings are supported in the head frame on a Zipstrip, not supported on the frame directly like a conventional racquet. The strip acts like a spring, imparting a degree of elasticity into the string-bed response. In the case of polyester, it significantly mitigates the translation of stiffness, vibration and impact shock to the frame and subsequently to a players arm, while preserving the inherent capacity of the strings to compress the ball and to achieve maximum spin as intended. The significance of this cannot be overstated. A player can potentially play with the stiffest polyester string all day every day without the serious physical risk that this would otherwise pose.
The fit of the Zipstrip with polyester string is so good that the Zipstrip actually improves the polyester performance. The subtle flex of the strip increases dwell time of the ball on the strings to further increase spin potential. At the time of ball impact, string tension drops slightly and reduces string-to-string friction as well, increasing the potential for "snap-back" to occur and enhancing spin potential even more. In the hands of an able player the combination is incredibly lethal and at the same time, easy on the body. The flex of the strip also adds some feel to the typical "plastic" quality of a stiff polyester string. It's truly a perfect match meant for this era of high-impact tennis.