## 1 Introduction  
Primitive reflexes (PRs) that emerge during the process of prenatal and neonatal neurological development provide the primary forms of movement. These are involuntary stereotypical movements controlled by the brain stem, occurring without the contribution of the cerebral cortex. They are useful during birth and for survival in the first year of life [1]. With the maturation of the central nervous system (CNS), PRs become inhibited and thus, conscious and functional motor reactions are developed. This integration process of PRs is the result of the synaptic plasticity of the CNS [2]. The persistence of PRs in children indicates a developmental delay of the nervous system or a neurological dysfunction [3], which will negatively impact the process of the child's development and decrease the ability of brain to effectively process sensory information [4]. In addition, retained primitive reflexes can have a negative impact on physical development [5; 6; 7; 8; 9; 10]; they might result in difficulties in the assumption of different body postures and their stabilization, and in motor control and motor coordination also [8; 11]. The usefulness of integrating retained reflexes instead of suppressing them in sports activities has already been an important issue in the past century [12], as the involuntary motor reactions elicited by retained primitive reflexes (changes in muscle tone, visible movement) hinder the development of appropriate motor patterns [8]. Asymmetrical tonic neck reflex (ATNR)  
The asymmetrical tonic neck reflex appears at the 18 th gestational week and remains active to the age of 3 to 9 months after birth. It is triggered by turning the head to the side, causing the limbs on the same side to extend and the limbs on the opposite side to flex [17], and the rotation of the torso also [18]. The ATNR helps the movement of the fetus in the womb, aids in the birth process, provides unobstructed breathing for prone infants by keeping the head turned to the side, and in addition, it promotes the increase in the extensor muscle tones and provides the basis of eye-hand coordination [1]. Prolonged presence of the ATNR can impact the movement development of the child. The most common symptoms are poor posture and the insufficiency or developmental delay of gross and fine motor skills [1; 8; 19]. Turning the head to the side makes movements crossing the midline of the body more challenging, affecting cross-lateral movements, crawling, the emergence of lateral dominance and the harmonized functioning of the two sides of the body [20]. Additionally, it makes it more difficult to track objects with the eye, as the eye still moves together with the head [21]. An active ATNR impedes balance control, as with head turning, the muscle tone increases in the homolateral limbs and decreases in the contralateral ones, that can even result in (unwanted) movement in the limbs and the torso [22]. Tonic labyrinthine reflex (TLR)  
The TLR Flexio pattern already appears in the womb and helps in assuming the fetal pose. The TLR Extensio pattern is active at the time of birth, assisting the fetus in passing through the birth canal. The TLR Extensio pattern integrates around the age of 4 months, while the integration of the TLR Flexio can be postponed to 3 years of age. This reflex is activated when the head is moved forwards or backwards. Extending the head backward creates a tension in the whole body, resulting in the extension of the limbs; flexing the head forward results in flexion in both the torso and the limbs [23]. The TLR helps achieving the \"straight-up posture\" from the fetal posture. It also helps strengthening the musclesthrough the contraction and relaxation of large muscle groups. Together with several other reflexes, it is responsible for head posture, balance and body posture [20]. A persisting TLR can cause problems in visual perception, orientation and timing, as well as inappropriate muscle tone, wrong posture and a poor perception of balance.