This study explores the impact of joint-level perturbations on coordination strategies during a reaching task, focusing on the motor learning process associated with such perturbations. While prior research has extensively investigated perturbations applied at the human end-effector level, joint-level perturbations have received limited attention. Given the redundancy of human limbs, joint-level perturbations may not necessarily affect the task, leading to potential differences in how the central nervous system adapts. In this experiment involving 55 subjects, participants performed reaching movements both with and without an exoskeleton applying various force fields (Transparent, Elastic, Viscous, Increase, or Decrease of Gravity). Movement kinematic data collected before and after exoskeleton exposure were compared. The findings indicate that, even when end-effector performance remains constant, coordination strategies often undergo significant changes. Notably, the viscous force field predominantly affects joint contributions, while the Elastic force field mainly influences the temporal organization of joints. Remarkably, over half of the subjects exposed to the transparent condition altered their coordination strategy. This research underscores the importance of monitoring coordination changes to gain a comprehensive understanding of how exoskeletons impact human motor control, facilitating their safe and widespread adoption.