reliability of knee kinematic parameters during drop jump landing in healthy male subjects

introduction: knee joint has the highest percentage of injuries among lower extremity joints especially in athletes and people with high activity levels. therefore, analyzing of knee movements has an important area of research in the bioengineering and rehabilitation fields. sharif human movement instrumentation system (sharif-hmis) is a new inertial sensor designed for movement analysis. the purpose of this study was to determine the reliability of knee kinematic parameters using sharif-hmis. material and methods: a total of 25 healthy male subjects (aged 18-28 years) participated in this study. sharif-hmis sensors were fixed with straps on dominant leg of the participants. thereafter, they performed double leg drop jump landing from a box with a height of 30 cm. linear acceleration and angular velocity were analyzed in initial contact phase. the test was performed 3 times at an interval of 1 hour. to assess the intra-rater reliability, intraclass correlation coefficient (icc) and standard error of measurement (sem) were calculated. results: icc in x, y and z planes was 0.99, 0.80 and 0.97 for linear acceleration and 0.50, 0.79 and 0.74 for angular velocity, respectively. furthermore, the sem in x, y and z planes were 0.03, 0.19 and 0.14 for linear acceleration and 0.007, 0.009 and 0.01 for angular velocity, respectively. conclusion: this study showed good test-retest reliability of knee kinematic parameters during double leg drop jump landing. hence, the use of sharif-hmis as a new and portable device is suggested for assessing knee joint movements. keywords: reliability; knee kinematic; sharif-human movement instrumentation system; acceleration; angular velocity; drop jump landing