Introduction
The inhibition or integration of primary reflexes, understood as the suppression of one function through the development of another (Goddard, 2005), together with the emergence of postural reflexes, which allow for functional and voluntary motor responses (Medina et al., 2015), plays a fundamental role in child development (Damasceno, Delicio & Mazo, 2005). This transition from primary to postural reflex is important as it connects basic postural and motor skills in the early years with the development of later motor skills (Goddard, 2005). In addition, it seems that active primary reflexes may make a child’s posture and motor skills look clumsy (Gieysztor, Pecuch, Kowal, Borowicz & Paprocka-Borowicz, 2020).
The most severe consequences of primary reflexes persistence are typically found in children with cerebral palsy, while milder persistence has been observed in children with reading difficulties and motor problems (McPhillips, Hepper & Mulhern, 2000). It has also been shown that the non-integration of primitive reflexes can cause developmental delays, and is associated with a variety of disorders, such as ADHD (Konicarova, Bob & Raboch, 2013), autism, learning difficulties (Bilbilaj, Gjipali & Shkurti, 2017; Hickey & Feldhacker, 2021; Matuszkiewicz & Gałkowski, 2021), dyspraxia (Pecuch et al., 2020), dyslexia, behavioral disorders (Rashikj-Canevska & Mihajlovska, 2019) or sensory processing disorders (Bilbilaj et al., 2017, Pecuch et al., 2020, Rashikj-Canevska & Mihajlovska, 2019).
If primary reflexes inhibition does not occur in a proper and orderly manner, children may develop, in addition to other difficulties, poor Motor Competence (MC) (Gieysztor, Choińska & Paprocka-Borowicz, 2018). Early signs of this may appear as difficulties in running, balance, aiming and catching tasks, poor visual coordination, lack of rhythm or defective spatial orientation (Gieysztor et al., 2018; Pecuch, Kołcz-Trzęsicka, Żurowska & Paprocka-Borowicz, 2018; Pecuch et al., 2020).
The primary reflexes considered in this research are those that are most directly related to the acquisition of coordination, balance and physical-sport skills: the Moro reflex (MR), the tonic labyrinthine reflex (TLR), the asymmetrical tonic neck reflex (ATNR) and the symmetrical tonic neck reflex (STNR).
Failure to inhibit the MR can cause difficulties in balance and coordination, which will become evident during ball games (Goodard, 2014). Furthermore, it can lead to excessive muscle tension (Bennet, 1988, cited in Goodard, 2015) which, if prolonged, would lead to fatigue (Goodard, 2015) and, consequently, poor task performance. Instead, non-inhibition of the TLR can lead to poor posture, weak muscle tone and low competence in activities involving temporal sequences (Kokot, 2006).
In the case of the ATNR, its non-inhibition may influence motor patterns involving the trunk and limbs, which attempt to align with the head (Henderson et al., 1993). This results in homo-lateral movements, instead of the cross-lateral pattern that should occur when walking, running or jumping (Goodard, 2015), which negatively contribute to the development of the crawling cross-lateral pattern (Krog, 2015).
Finally, if the STNR remains active, as with the MR, it may increase children’s difficulties in properly throwing or catching a moving object (Goodard, 2005). Furthermore, this reflex acts as a developmental bridge to the locomotion stage, when children begin to crawl on their hands and knees (Krog, 2015). Although it allows the child to adopt the quadrupedal position, it will prevent progress in this position if it is not properly integrated (Goodard, 2015).
The crawling pattern, another variable considered, favors the integration of the right and left sides of the body, the acquisition of adequate spatial awareness and the development of hand-eye coordination (Hannaford, 2005). Besides, it contributes to the development of motor skills associated with other developmental areas, such as social cognition and language (Leonard & Hill, 2014). It is also important for a child’s overall development, and physical, psychological and general well-being (Barnett et al., 2016), although most authors agree that it is not a necessary milestone (Oldak-Kovalsky & Oldak-Skvirsky, 2015).
There is broad evidence that primary reflex activity can exist in the general population (Demiy et al., 2020; Gieysztor, Sadowska & Choińska, 2017; Gieysztor et al., 2018; Gieysztor et al., 2020; Grigg, Fox-Turnbull & Culpan, 2018; Hickey & Feldhacker, 2021; Matuszkiewicz, & Gałkowski,2021; Pecuch et al., 2020; Rashikj-Canevska & Mihajlovska, 2019). Plentiful research has been conducted in children with several difficulties (Bilbilaj et al., 2017; Chinello, Gangi &Valenza, 2018; Konicarova et al., 2013; Mc Phillips & Jordan-Black, 2007; Pecuch et al., 2018, Taylor, Houghton & Chapman, 2004). However, there are few studies assessing the lack of inhibition of these reflexes and their relationship with MC in early childhood (Gieysztor et al., 2018; Pecuch et al., 2018), despite it being a developmental stage in which the first signs of poor reflex inhibition become apparent (Gieysztor et al., 2018).
For these reasons, the aims of the study were to analyze the relationships among the level of inhibition of primary reflexes, MC and the development of the crawling pattern in children, and to assess these relationships according to the participants’ gender. These aims were specified in four hypotheses: (1) the non-inhibition of primary reflexes will be higher in those children who show lower MC, (2) the non-inhibition of reflexes will be lower in those children who have developed the crawling pattern, (3) having developed the crawling pattern will be associated with higher MC and, finally, (4) the non-inhibition of primary reflexes will be higher in male participants.