Background The knee joint is one of the most frequently injured joint in sports. Sport injury is mostly non-contact in nature and often occur during single leg landings (SLL). SLL are also a common task performed in many sports. The reliability of different landing tests has been examined in the literature, but mostly limited to one test and most studies did not report the standard error of measurement (SEM) of their measurement. Although three-dimensional (3D) motion analysis is the gold standard for examining lower limb biomechanics, its extension to a clinical setting or to a larger sample size is limited. Therefore, researchers have examined 2D motion analysis and found it a good alternative.

Objective To establish the reliability and SEM of a 2D movement analysis system to measure the kinematics of lower extremity during multidirectional SLL.

Design Test-retest reliability study.

Setting University laboratory.

Patients (or Participants) 12 moderately active university students.

Assessment of Risk Factors 2D knee and hip frontal plane kinematics were collected for both legs while the subjects performed multidirectional SLL. A retest session was repeated one week later.

Main Outcome Measurements Frontal plane projection angle (FPPA) and hip adduction angle.

Results The ICC for the different variables ranged between 0.67 and 0.96, indicating good to excellent reliability for all 2D variables in all tasks. SEM ranging between 0.69° and 2.7° which can be an evidence for small measurement error.

Conclusions The 2D biomechanical variables were reliable when examining multidirectional SLL tasks in a moderately active healthy population. Furthermore, multidirectional SLL is a reliable test to examine the lower extremity biomechanics.