Motor restlessness in babies can be caused by various factors - biological and environmental. Biologically, it may be related to the baby's nervous system and maturity. Some babies have a higher level of energy from birth and react more intensely to stimuli. They seek stimulatory input to a greater extent e.g. by kicking their feet against the floor/mattress or by tossing and turning in bed. The brain is constantly developing, and therefore, the experience of motor restlessness can vary from baby to baby. It may occur while your baby is learning something new about his/her body, or due to the natural development of the brain. This can result in difficulty in settling down or sleeping. Environmental factors may include overstimulation, which occurs when a baby is exposed to excessive noise, light, or activity. This can be overwhelming, causing restlessness and manifesting physically in the body as trembling or what may appear to be uncontrollable movements of the arms and legs.

Sleep patterns play a crucial role. Infants with irregular sleep routines or experiencing sleep disturbances may be more prone to motor restlessness. Additionally, sensory processing, i.e., how a baby experiences and reacts to sensory stimuli, is a clear factor. During the first years, babies and children develop the ability to sort and process impressions. It varies how this happens, which is why children who are particularly sensitive to environmental sensitivity may exhibit signs of motor restlessness as a reaction to overwhelming or unpleasant sensory experiences.