We present a solution to estimate in-vivo the joint dynamics of the human limbs during passive movements. The method is based on well-known modelling and approach used in robotics that allow simultaneous multi-joint estimation. The modelling of the human body and the human joint as well as the method are described. The experimental set-up based on the use of an optical motion capture system is detailed. Three types of movements are recorded and used to perform the identification. We concluded that designed movements and movements from clinical diagnosis of neuromuscular diseases are good to perform the identification; however swing of the arms during normal walk does not provide enough excitation to obtain consistent results.