Motor function, among other abilities such as communication, contribute heavily to the quality of life of an individual. The coordination of precise movements in order to perform an intended action, such as walking or writing, is managed by the motor system. The functioning of this system is based on the cooperation of the central nervous system, the musculoskeletal system, as well as the sensory system.
Development of motor skills follows three distinct principles; cephalocaudal, proximal-distal, and general to specific, as observed by Dr. Arnold Gesell. Gesell’s principle of development direction suggests that motor development begins in an orderly fashion from head to toe and closest to the body to the farthest part (Salkind, 2004). As the control over these parts is improved upon, an individual begins to develop finer movement skills.
Motor skills are categorized as,
- Gross Motor Skills: These skills involve large muscle groups and are acquired as part of childhood motor learning. The skills can be further divided into locomotor skills and object control skills.
- Fine Motor Skills: These skills involve the smaller muscles, including hands and face, to control smaller movements. Fine motor skills are acquired following the development of gross motor skills. Further, unlike gross motor skills that are retained even after a period of no-use, fine motor skills may not be retained if not used.
The quantitative and qualitative changes in motor skills are dependent on the maturation of the central nervous system and the muscular system. Motor learning progresses through three stages: the cognitive phase, the associative phase, and the autonomous phase. The progression of motor learning can be understood through Thorndike’s (empirical) Law of Effect. A positive association between motor skill and the outcome results in the promotion of learning of the skill (Adams, 1971). As the positive association grows stronger, robust neuronal modifications occur (Dayan, & Cohen, 2011; Kapogiannis, Campion, Grafman, & Wassermann, 2008). However, it is simply not just the feedback of an action that influences motor learning. Other factors such as physical health, genetic factors and mental health among others, can also contribute to the rate of motor development (Ferguson, Cassells, MacAllister, & Evans, 2013; Golding, Emmett, Iles-Caven, Steer, & Lingam, 2013). On the whole, though motor development does not depend on age and experience, it is, to a great extent, influenced by them (Salkind, 2004).
Delay in acquiring of these skills or impairments can be markers of diseases and disorders such as Autism Spectrum Disorder (McPhillips, Finlay, Bejerot, & Hanley, 2014) and Parkinson’s disease (Opara, Małecki, Małecka, & Socha, 2017). Partial or complete loss of motor function may also be a result of injuries to the musculoskeletal system or nervous system. Apart from these causes, deficits in the sensory system can also exhibit themselves as motor control impairments.