Although some studies have been conducted to validate the accuracy of thePerception Neuron Studio (PNS) inertial motion capture system in quantifying kinematics, a comprehensive analysis of the more complex upper body is still lacking, which affects the ability of this system to provide accurate kinematic data for further biomechanical performance analysis. This study presents a thorough analysis of thissystem by quantifying the validity and intra/inter-session reliability at different task complexities and movement speeds.