• Voluntary motor commands and spinal reflexes both produce body movements that activate sensors located in the muscles, joints, tendon and skin.
• It is unknown whether perceptions generated by the sensory inputs from voluntary movements can be distinguished from perception of inputs due to spinal reflexes. Surprisingly, the perception of reflexes remains largely unaddressed.
• Knee-jerk reflexes were perceived accurately on the basis of proprioceptive inputs alone, but perception was poorer when volunteers were instructed to voluntarily kick backwards or forwards as rapidly as possible in response to the tendon tap.
• This demonstrates that sensory inputs from a spinal reflex lead to movement perception. However, there is no clear perceptual landmark separating reflexes from voluntary movements, even when the two movements involve antagonistic muscles.
• These findings help us to understand how sensory feedback from body movement leads to movement perception and awareness of action.