Do placebo effects improve my skill? The influence of placebo effects on motor control and learning

Motor performance is multifaceted and refers to several different dimensions, including force production, precision control, movement speed, resistance to fatigue, motor adaptation, and motor skill learning. The investigation of the placebo effect on different motor functions represents a useful approach to extend our knowledge about the pervasive nature of this effect and build new models for the study of its neural underpinnings. To date, while many behavioral studies have demonstrated the efficacy of placebo and nocebo procedures in influencing some aspects of motor performance, others remain unexplored. In this chapter, two categories of motor functions will be considered: those performed with the upper limb and those requiring the whole body. Within the first category, evidence using a fundamental function through which repeated practice forms isolated movements into well-performed skills will be presented on force production, goal-directed movements, and motor sequence learning. Within the second category, evidence will be presented on balance control, a fundamental motor function, which allows to maintain a stable stance and to prevent falls, as well as on leg-extension performance.