Motor development delay

Is your 6-month-old baby not rolling over yet? Does your infant seem less active than other children his or her age? These observations can be cause for concern. The infant’s sucking reflex is one of the milestones assessed. An evaluation helps distinguish between normal developmental variation and a difficulty that requires follow-up. Our physical therapists support families through this process. This guide will help you understand your child’s motor development and determine when an evaluation would be beneficial.

What is a motor development delay?

A motor development delay refers to the acquisition of skills, such as sitting or walking, later than expected for the child’s age. The professional observes the child’s movements and may use an assessment that compares the same tasks in children of the same age. Missing a single milestone is not sufficient to make a diagnosis.

The timeline describes what is observed; it does not yet specify the cause or the course of the condition. Some children go on to acquire the expected skills. Others have a disorder that requires long-term support, such as a condition affecting the muscles or the nervous system. Assessment and follow-up help determine the child’s needs. The clinical report from the American Academy of Pediatrics, a U.S. association of pediatricians, explains these different outcomes. Our guide on childhood developmental disorders explains when a disorder requires special monitoring.

Milestones are skills that serve as benchmarks, such as holding up one’s head or sitting up. The ages at which these skills are acquired vary. The ranges below describe this variation but are not a substitute for an evaluation if you have any concerns. For a preterm baby, the healthcare professional also takes into account the corrected age, calculated based on the estimated due date. A pediatric fact sheet explains this calculation.

What are the typical developmental milestones for the first year and the months that follow?

Key motor milestones in the first year include head control, rolling over, sitting up, and moving with support. The order in which these milestones occur and the age at which they appear vary. The milestones established by the Centers for Disease Control and Prevention (CDC), a U.S. public health agency, describe what most children can do at a given age. The World Health Organization (WHO) age ranges describe a broader spectrum of observed ages.

The WHO study followed 816 children from five countries. Its ranges extend from the first to the 99th percentile, covering some of the earliest to the latest ages observed. These ranges are used to describe development; they are not a guideline suggesting that you should wait until a child reaches the upper limit before seeking medical advice. Overall progress and warning signs are also important.

What causes a motor development delay?

Movement delays can be related to limited opportunities for movement, muscle or joint problems, or a disorder of the nervous system. Several factors may contribute. Muscle tone refers to the tension of muscles at rest and the resistance felt when moving a limb.

Opportunities for movement depend, among other things, on the positions and play space provided to the baby. A baby who spends a lot of time in static positions—such as a baby carrier, car seat, or swing—has fewer opportunities to practice certain movements. In a survey of parents of babies under 19 months, spending more time in these devices was associated with poorer outcomes for fine motor skills in the hands. Longer periods spent in positioning cushions were associated with poorer outcomes for gross motor skills. However, reported use of these devices was not linked to delays in most of the areas assessed.³ Short periods of tummy time, while the baby is awake and under supervision, provide the baby with additional opportunities to practice supporting their body.⁴ These associations do not prove that a parent caused their child’s delay.

Muscle and joint problems, such as torticollis, limit movement and can delay certain developmental milestones. A study comparing 82 babies with torticollis to 40 babies without torticollis found that certain milestones were delayed by up to 10 months.⁵ A follow-up study of 81 children between the ages of 3.5 and 5 years found no increased risk of developmental delays in the group that had had torticollis. This result is reassuring, though it does not prove that treatment alone accounts for the children’s development.⁶

Disorders of the nervous system can affect movement, strength, or muscle tone. A doctor should investigate the cause if these signs are present. Physical therapy can complement this evaluation, particularly throughthe neurodevelopmental approach, which facilitates movement and postural control.

The follow-up aims to understand the child's challenges and support his or her progress. It tailors activities to the child's abilities and arranges for any other necessary evaluations.

How to recognize a motor delay in your child?

Possible signs of motor delay include delayed skills, limited progress, and significant differences in movement between one side of the body and the other. Observe your child while they play and note any concerns you have. The professional will discuss these observations with you.

• Marked asymmetry: The child moves one side of their body more or makes certain movements only to one side
• Severe hypotonia: The child cannot hold up his or her head or trunk when picked up, at an age when better control would be expected.
• Hypertonia: The legs and back are very stiff and difficult to bend

If you notice significant asymmetry, unusual floppiness, or stiffness, talk to your child’s doctor. A physical therapy evaluation can also help identify your child’s difficulties and recommend appropriate activities. If your baby suddenly becomes very floppy or weak, or has trouble breathing, seek immediate medical care. Persistent floppiness accompanied by difficulty feeding also requires urgent medical attention. British guidelines specify these signs that medical attention is needed.

The loss of a previously acquired skill requires a medical evaluation. A baby who has stopped doing what he or she used to do should be evaluated, regardless of age. The doctor may refer the child to a developmental or pediatric neurology team.

Why is early intervention important?

Early intervention makes it possible to offer age-appropriate activities as the child learns his or her first movements. It also allows for the necessary assessments to be conducted without delaying support. The skills developed in the first year lay the groundwork for more complex movements, but the child continues to learn beyond that point.

The brain changes as we grow and gain experiences: this ability is called plasticity. Certain periods of development are particularly sensitive to these experiences. This underscores the importance of tailored support, without setting a deadline beyond which progress would be impossible.⁷

A review of ten studies involving infants with motor delays or at risk of delays reports progress in certain early intervention programs. Activities that encourage the child to participate in their own movements are particularly encouraging. Results vary by child and program, and further high-quality studies are needed. This research does not guarantee complete catch-up for every cause.⁹

When should you consult a pediatric physiotherapist?

You can consult a pediatric physical therapist as soon as you have concerns about your child’s movements or development. Be sure to also discuss your observations with your child’s doctor. You do not need a doctor’s referral to see a physical therapist in a private clinic; however, be sure to check your insurance coverage. The Ordre professionnel de la physiothérapie du Québec outlines the procedures for accessing care. Our pediatric physical therapy program explains how assessments and follow-up care are tailored to your child’s age.

• Your child is not reaching the expected milestones for their age
• You notice an asymmetry in their movements
• Your baby has persistent difficulty with tummy time
• You have a concern, even a vague one, about their development

Parents' intuition matters. If something seems different about your child, a professional assessment can either reassure you or guide you toward appropriate interventions.

You can request an evaluation right now. The professional will be able to suggest activities, monitor progress, or request additional evaluations based on the signs observed.

If you have any concerns, a physical therapist can assess your child's current progress and show you how to encourage movement in daily life. What matters isn't a single missed milestone, but how movement progresses over time.

How does physiotherapy help motor development?

Physical therapy supports motor development through games, positions, and exercises tailored to the child’s specific challenges. The physical therapist begins by observing the child’s movements, examining their muscles and joints, and then discussing their daily routines. In particular, the therapist looks for torticollis or unusual muscle tone and uses age-appropriate assessment criteria. This assessment also checks for the persistence of primitive reflexes, such as the plantar grasp reflex.

The physical therapist will show you play positions and movements suited to your baby. Together, you’ll choose toys and activities that encourage your baby to move. The exercises address the specific challenges observed and are incorporated into playtime. To stimulate cross-coordination, we offer progressiveexercises such asthe advanced-level cross-walking exercise.

Supporting parents plays a central role in the care process. The physical therapist will practice the exercises and positions with you so that you feel comfortable doing them at home. You support your child’s learning on a daily basis, with the help of professionals; you don’t have to become your child’s therapist.

What exercises can you do at home to stimulate development?

Free play on the floor and short periods of tummy time give the baby opportunities to practice moving. The baby should be awake and supervised by an adult who is also awake. Gradually increase the duration of these periods based on the baby’s tolerance and follow the adjustments recommended by the baby’s healthcare provider.

Tummy time strengthens the muscles that support the head and trunk. It also helps babies practice supporting themselves on their arms. A review of 16 studies involving 4,237 babies links tummy time to improved motor skills, particularly rolling over and moving around. Most studies observe associations; they do not, on their own, prove that tummy time causes all of these developments.⁴

For each sleep period, place your baby on his or her back in a safe sleeping area. If your baby falls asleep while playing on his or her stomach, move him or her back to the safe sleeping area on his or her back. Stomach play is only recommended during supervised wake times. Canadian recommendations on safe sleep explain this distinction.

• Limit the amount of time your baby spends in car seats, infant carriers, and Jolly Jumper-type jumpers during wakeful periods. Always use the appropriate car seat for car trips.
• Encourage free play on the floor in a safe space
• Vary positions during waking hours
• Alternate sides when carrying or feeding your baby

Offer age-appropriate toys with different textures that are easy to explore. Place them within easy reach to encourage your baby to look at and touch them. Choose objects without small parts that could be swallowed, and stay close to your baby.

If these tips seem difficult to apply, pediatric physiotherapists are here to support you.

What are some common questions about engine lead time?

Frequently asked questions about motor development delays focus on babies who don't crawl, catching up on skills, and ways to make tummy time more bearable.

It may be normal for a baby not to crawl yet; whether this develops depends on the cause, and playing on the stomach is a skill that develops gradually. These three frequently asked questions are discussed in detail below.

Some babies go straight to crawling on all fours without first crawling on their stomachs. A study that followed 28 babies until they began walking observed this pattern in 13 of them. The absence of crawling on all fours does not, by itself, indicate a problem. In the WHO study, 4.3% of children did not crawl this way. This figure refers to moving on hands and knees, not to sliding on the stomach.² The professional assesses the child’s overall movements and their progression. Asymmetry, a loss of motor skills, or other difficulties do, however, require an evaluation.

Some children catch up; others continue to need support. The cause, current difficulties, and how they evolve guide the course of follow-up care. Early intervention programs can improve motor skills, but a full recovery is not guaranteed for every child.⁹ A neurological cause does not preclude all progress: goals are tailored to the child’s abilities and needs.

Start with a very short period of time—for example, 30 seconds—if your baby can tolerate it. Sit facing your baby to encourage him or her. You can also place your baby on your chest or thighs, supporting his or her head as needed, while staying awake and keeping an eye on him or her. Gradually increase the duration and take a break if your baby seems uncomfortable. The American Academy of Pediatrics illustrates these positions. If the difficulty persists, ask the healthcare professional caring for your child for adjustments.

References

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1. Nelson EA, Yu LM, Wong D, Wong HY, Yim L. Rolling over in infants: age, ethnicity, and cultural differences. Dev Med Child Neurol. 2004;46(10):706-9. (Back to section: 1)
2. WHO Multicenter Growth Reference Study Group. WHO Motor Development Study: windows of achievement for six gross motor development milestones. Acta Paediatr Suppl. 2006;450:86-95. (Back to sections: 1, 2, 3)
3. Alghamdi ZS, Lobo MA. Parent-Reported Container Use Is Associated with Infants' Motor Development. Pediatr Phys Ther. 2025;37(4):438-445. (Back to section: 1)
4. Hewitt L, Kerr E, Stanley RM, Okely AD. Tummy Time and Infant Health Outcomes: A Systematic Review. Pediatrics. 2020;145(6). (Back to sections: 1, 2)
5. Ohman A, Nilsson S, Lagerkvist AL, Beckung E. Are infants with torticollis at risk of a delay in early motor milestones compared with a control group of healthy infants? Dev Med Child Neurol. 2009;51(7):545-50. (Back to section: 1)
6. Öhman A, Beckung E. Children who had congenital torticollis as infants are not at higher risk for a delay in motor development at preschool age. PM R. 2013;5(10):850-5. (Back to section: 1)
7. Ismail FY, Fatemi A, Johnston MV. Cerebral plasticity: Windows of opportunity in the developing brain. Eur J Paediatr Neurol. 2017;21(1):23-48. (Back to section: 1)
8. Gündoğmuş E, Bumin G, Yalçın SS. Effect of Early Intervention on Developmental Domains and Parent-Child Interaction Among Children With Developmental Delay: A Randomized Controlled Study. Am J Occup Ther. 2024;78(6). (Back to section: 1)
9. Dumuids-Vernet MV, Provasi J, Anderson DI, Barbu-Roth M. Effects of Early Motor Interventions on Gross Motor and Locomotor Development for Infants at Risk of Motor Delay: A Systematic Review. Front Pediatr. 2022;10:877345. (Back to sections: 1, 2)