Atkinson G, Speirs L
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK.
Percept Mot Skills. 1998 Jun;86(3 Pt 2):1335-8. doi: 10.2466/pms.1998.86.3c.1335.
With informed consent, 6 competitive tennis players performed alternate 15 "first" (emphasis-speed) serves and 15 "second" (emphasis-accuracy) serves at 09:00, 14:00 and 18:00 hours. Serve velocity was measured by the digitisation of video footage of each serve. The Hewitt Tennis Achievement Test was employed to measure the accuracy of serve. The amount of spin imparted on the ball was not measured. First serves were at all times of day faster than second serves. First serves were faster but least accurate at 18:00 hours, the time of day that body temperature and grip strength were highest. At 09:00 hours, first serves were just as accurate as second serves, even though velocity of first serves was higher. No effects for time of day were found for the speed and accuracy of second serves. These results indicate that time of day does affect the performance of tennis serves in a way that suggest a nonlinear relationship between velocity and accuracy.
在获得知情同意后，6名竞技网球运动员于上午9点、下午2点和下午6点分别进行了15次“第一”（强调速度）发球和15次“第二”（强调准确性）发球。通过对每次发球的视频片段进行数字化处理来测量发球速度。采用休伊特网球成就测试来测量发球的准确性。未测量施加在球上的旋转量。一天中任何时候的第一发球都比第二发球快。第一发球在下午6点时速度更快但准确性最差，而下午6点是体温和握力最高的时段。在上午9点时，第一发球的准确性与第二发球相同，尽管第一发球的速度更高。未发现一天中的时间对第二发球的速度和准确性有影响。这些结果表明，一天中的时间确实会以一种表明速度与准确性之间存在非线性关系的方式影响网球发球的表现。
