Juvenile idiopathic arthritis (JIA) is a chronic disease characterized by persistent joint inflammation. The immune system disruption that leads to overproduction of pro-inflammatory cytokines (TNF-α, IL-1, IL-6) is a cascade of events on different levels—some molecular, some cellular, and some systemic. Our objective is to identify the mechanisms through which physical activity is liable to mediate inflammatory balance in autoimmune disease settings, and specifically in JIA patients.