Infant Development
Top Contributors - Robin Tacchetti and Jess Bell
Introduction
Development refers to changes in abilities and skills that improve daily functioning. Understanding how infants develop motor skills is fundamental to paediatric physiotherapy practice. Recognising typical developmental patterns allows clinicians to identify when a child's development may be diverging from expected norms and to guide intervention accordingly.
Research in infant motor development has identified consistent, predictable patterns in how movement skills are acquired. Four key principles describe the typical direction and progression of this development:[1][2][3][4]
- cephalocaudal development
- proximodistal development
- general to specific movement
- reflexive to voluntary movement
Each of these principles is explored in the sections below. While these principles describe the typical direction and sequence of motor development, it is important to note that individual children progress at varying rates. Development is shaped by the interaction of hereditary factors and environmental influences (family, culture and social influences), meaning that the pace and pattern of skill acquisition differ between children.[1][5][6]
Cephalocaudal Development
Motor skills are acquired in a cephalocaudal direction (i.e., head-to-tail).[1] Infants develop head control first, followed by shoulder girdle and arm control, then trunk control, and finally lower limb and foot control.[2]
This progression is clearly visible in prone development. At one month, infants have minimal head control and lie with their face close to the supporting surface. By two to three months, they begin to lift their head; their chin clears the surface, but their arms remain tucked behind their shoulders. At three to four months, infants typically achieve the prone prop position, with their elbows beneath their shoulders, beginning to weight-bear through their arms. By five to six months, they can typically prop on extended arms and have increasing upper trunk control.[2]
Proximodistal Development
Motor control develops from the centre of the body outwards (proximodistal),[1] meaning that gross motor skills involving the trunk and shoulders develop before the fine motor skills of the hands and fingers.[2]
This progression is also visible in the prone development sequence described above. In the early months, infants demonstrate central control through head lifting and midline stability. At this stage, their arms contribute little. As development progresses, infants start to bear some weight through their elbows, and eventually, they are able to extend their elbows while pushing through their hands. Finger control and the ability to manipulate small objects develop later.[2]
General to Specific Movement
Early infant movement is characterised by generalised, non-purposeful activity involving the whole body. Over time, as the nervous system matures, these broad movement patterns become increasingly specific and goal-directed.[2]
General movements (GMs) are complex, whole-body movements involving the arms, legs, neck, and trunk in variable sequences.[7] In the first two months of life, GMs are characterised by writhing movements that vary in intensity, speed, and range of motion. Rotations around the limb axes and slight changes in direction create an impression of fluency. Writhing movements have a gradual onset and a gradual end.[2][8][9]
Fidgety movements (FMs) can appear as early as six weeks, but usually occur from around nine weeks until 16-20 weeks. FMs are small movements of moderate speed with variable acceleration of the neck, trunk, and limbs in all directions. They fade as antigravity and intentional movements begin to dominate.[2] The presence and character of FMs are considered good indicators of the integrity of the infant's nervous system.[10][9]
As development progresses, these generalised movements give way to more specific, purposeful actions. An infant who initially moves arms and legs in an undirected manner will gradually develop the ability to reach deliberately towards a specific object.[2]
Reflexive to Voluntary Movement
Infants are born with a set of primitive reflexes. These reflexes are involuntary, survival-oriented motor responses that develop in utero and strengthen postnatally. Over time, as the nervous system matures, these reflexes integrate and are replaced by voluntary, goal-directed movements. The absence or persistence of a primitive reflex may indicate neurological concerns.[2][11][12] For a detailed overview of primitive reflexes, see Infant Terminology and Reflexes.
Maturation refers to the biological growth and changes that occur naturally over time in the brain and nervous system. This maturation is what enables the progressive shift from reflexive to voluntary motor control.[1]
Voluntary movements are volitional and goal-directed—for example, an infant reaching deliberately towards a toy. This transition from reflexive to voluntary control reflects the progressive maturation of higher cortical centres.[2]
Additional Considerations in Infant Motor Development
Flexed Posture
In infants born at term, hip and knee range of motion (ROM) is limited by muscle tightness and increased muscle tone (stiffness) in the lower limb flexor muscles. This flexed posture occurs because there is restricted space in the uterus in the last weeks of intrauterine life. This position is referred to as neonatal hip flexion contracture.[7]
During periods of relative quietening of movement, the hips are flexed, abducted and laterally rotated, with the infant's feet lifted off the supporting surface. The knees cannot be fully extended and, when passively extended, recoil back to a more flexed position. During newborn kicking, there is a decrease in the range of hip flexion along with some knee extension, while the ankle remains in dorsiflexion with the toes in flexion. This relative extension of the hip and knee is followed by a return to the more flexed resting position.[7]
Muscle Synergies
Muscle synergies refer to consistent coordination patterns that generate specific motor actions.[13] The multi-segmented structure of the body produces the varied movement patterns seen in human actions, but also presents a considerable challenge for neural control. To simplify control of the many degrees of freedom inherent in a multi-segmented body, spontaneous infant movements are constrained and organised into synergies.[14]
Lower limb synergy patterns include intralimb coupling of:[15]
- hip flexion, knee flexion and dorsiflexion
- hip extension and knee extension
Upper limb synergy patterns include:
- shoulder and elbow extension with wrist and finger extension
- elbow flexion with finger flexion
Summary
Infant motor development follows four key principles: cephalocaudal, proximodistal, general to specific, and reflexive to voluntary. These principles describe the typical direction and sequence in which movement skills are acquired, underpinned by the progressive maturation of the central nervous system. Recognising these patterns enables clinicians to identify typical development and detect early signs of developmental delay.
Resources
- Understanding Newborn Behaviour
- Development Skills Training for the 1-2 month old
- Motor Development Principles
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Singh R, Bisht N, Parveen H. Principles, milestones and interventions for early years of human growth and development: an insight. Int J Curr Microbiol Appl Sci. 2019;8(6):181-90.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Eskay K. Infant Motor and Cognitive Development Course. Physiopedia Plus, 2023.
- ↑ Eliks M, Gajewska E. The Alberta Infant Motor Scale: A tool for the assessment of motor aspects of neurodevelopment in infancy and early childhood. Front Neurol. 2022 Sep 14;13:927502.
- ↑ Xiong Y, Hu X, Cao J, Shang L, Yao Y, Niu B. Development of gross motor skills in children under the age of 3 years: a decision tree approach. Front Public Health. 2024 Oct 22;12:1421173.
- ↑ Adolph KE, Hoch JE. Motor development: embodied, embedded, enculturated, and enabling. Annu Rev Psychol. 2019 Jan 4;70:141-164.
- ↑ Varas-Meis A, Alonso-Arbiol I, Gallarin M, Lillo-Navarro C. Parent-infant attachment and gross motor development during the first 2 years of life: a systematic review. Nurs Health Sci. 2025 Dec;27(4):e70267.
- ↑ 7.0 7.1 7.2 Von Hofsten C, Rosander K. The development of sensorimotor intelligence in infants. Advances in child development and behavior. 2018 Jan 1;55:73-106.
- ↑ Maeda T, Kobayashi O, Eto E, Inoue M, Sekiguchi K, Ihara K. An algorithm for the detection of general movements of preterm infants based on the instantaneous heart rate. Children (Basel). 2022 Dec 29;10(1):69.
- ↑ 9.0 9.1 Hadders-Algra M, Tacke U, Pietz J, Rupp A, Philippi H. Predictive value of the General Movements Assessment and Standardized Infant NeuroDevelopmental Assessment in infants at high risk of neurodevelopmental disorders. Dev Med Child Neurol. 2024 Oct;66(10):1361-1368.
- ↑ Einspieler C, Marschik PB, Prechtl HF. Human motor behavior: Prenatal origin and early postnatal development. Zeitschrift für Psychologie/Journal of Psychology. 2008;216(3):147.
- ↑ Wang M, Yu J, Li H, Zhao C, Li Y, Yang X. Development of the children's primitive reflex integration assessment scale. Front Psychol. 2025 Jan 22;16:1495990.
- ↑ McWhirter K, Steel A, Adams J. The association between learning disorders, motor function, and primitive reflexes in pre-school children: A systematic review. J Child Health Care. 2024 Jun;28(2):402-428.
- ↑ Goudriaan M, Papageorgiou E, Shuman BR, Steele KM, Dominici N, Van Campenhout A, Ortibus E, Molenaers G, Desloovere K. Muscle synergy structure and gait patterns in children with spastic cerebral palsy. Developmental Medicine & Child Neurology. 2022 Apr;64(4):462-8.
- ↑ Safavynia S, Torres-Oviedo G, Ting L. Muscle synergies: implications for clinical evaluation and rehabilitation of movement. Topics in spinal cord injury rehabilitation. 2011;17(1):16-24.
- ↑ Versfeld, P. Newborn Infant Course. Plus. 2022