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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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THE ROLE OF KNEE POSITIONING AND RANGE-OF-MOTION ON THE CLOSED-STANCE FOREHAND TENNIS SWING |
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Steven M. Nesbit  ,
Monika Serrano and Mike Elzinga |
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Associate Professor Department of Mechanical Engineering, Lafayette College Easton, PA, USA |
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© Journal of Sports Science and Medicine (2008) 7, 114 - 124 Search Google Scholar for Citing Articles |
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| ABSTRACT | |||
| This paper discusses the role of knee positioning and range-of-
motion on the closed-stance forehand tennis swing. The analyses of tennis
swing mechanics were performed using a computer model comprised of a full-body
model of a human and an inertial model of a racket. The model was driven
by subject forehand swings (16 female college-level subjects) recorded with
a high-speed digital motion analysis system. The study discovered that both
initial knee positioning and range-of-motion were positively related to
racket velocity and characteristic of more skilled players. The direct effects
of knee positioning and range-of-motion on racket movement are minimal,
however there are several indirect biomechanical effects on the forehand
motion such as movement of the body mass center, work of the knee, hip and
back joints, and the angular range-of-motion of the hips and torso. Some
of these indirect effects were related to racket velocity and characteristic
of more skilled players. Factors that influenced knee positioning and range-of-motion
include years of playing, amount of coaching, and body style. Efforts to
both increase and restrict the knee movements of the subjects resulted in
substantially lower racket velocities (and other detrimental biomechanical
effects) implying that there may be optimal knee positions and range-of-motion
for a given subject. The most skilled subject exhibited a high degree of
consistency of knee positioning and range-of-motion. This subject adjusted
for varying ball height through modified initial knee positioning while
maintaining fairly constant ranges-of-motion.
Key words: Biomechanical models, tennis swing, forehand, knee joint. |
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