Motor Strategies Learned during Pain Are Sustained upon Pain-free Reexposure to Task

Abstract

Pain affects movement planning and execution, and may interfere with the ability to learn new motor skills. Variations among previous studies suggest task-specific effects of pain on the initial acquisition and subsequent retention of motor strategies. The present study assessed how acute pain in the anterior deltoid muscle affects movement accuracy of fast arm-reaching movements during force field perturbations and upon immediate pain-free repetition of the same task. Despite having slower initial rate of improvement, individuals who experienced pain during training achieved the same final performance as pain-free controls. However, pain altered the strategy of muscle activation adopted to perform the task, which involved less activity of the shoulder and arm muscles. Strikingly, motor strategies developed during the first exposure to the force field were retained upon reexposure to the same perturbation after resolution of pain. Although reduced muscle activation may be interpreted as metabolically efficient, it reduces joint stability and can have negative consequences for joint integrity. These results demonstrate that alternative motor strategies developed in the presence of pain can be maintained when training is resumed after resolution of pain. This effect could have deleterious consequences if it applies when learning motor skills in sports training and rehabilitation.