| 摘要 |
<p>A racket having strings strung across the head portion of the frame in which the strings have threaded end portions for engagement with correspondingly threaded nuts. Additionally, the threaded portion of the string can extend the entire length of the string so as to provide the string with a surface that imparts more spin to the ball. The surface of the strings is also provided with markings. When the string is tensioned in the frame through turning of the nuts, the distance between markings is increased due to elongation of the string. This elongation can be translated into a particular increase in tension by use of a suitably calibrated scale.</p> |
