Correlation between lower body stiffness and agility in racket-sports athlete

Stiffness is an index for determination of elastic properties of body and its optimum range is different in various motion patterns. The Spring-mass model is used for calculating stiffness. In this method, the whole leg is modeled with a linear simple spring. The aim of this study is determination of lower body stiffness and evaluation of its correlation with agility, as dominant motion pattern in racket sports. 12 national-level male racket-players (age: 25±4 years & weight: 80±7 kg) participated voluntarily in this study. Leg and vertical stiffness were measured during running on treadmill and hopping test. Pearson’s correlation coefficients were used to examine the relationships between stiffness and agility test records. Statistical significance was set at P< 0.05. There wasn’t significant correlation with agility in this study. The reason could be of the contrast influence of knee and ankle stiffness on performance. This problem requires separate evaluation of joint stiffness.