Motor milestones: How do babies develop during the first two years?

© 2022 GWEN DEWAR, PH.D., ALL RIGHTS RESERVED

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Motor milestones mark exciting transitions in a babe'south life, but there is no single, universal schedule that all babies follow.

For instance, past 6 weeks, most babies can lift up their heads while they lie on their stomachs.

By 3 months, most babies can too lift up their chests, using their arms for support.

Past four to 5 months, the boilerplate baby tin can roll over, from back to stomach (Nelson et al 2004).

But the exact timing varies. Some babies have learned to roll over past 2 months! And the same is true for other motor milestones.

For case, studies suggest that more than l% of infants tin can

• sit down upward, unsupported, by six months,
• crawl on easily and knees by 8 and a half months,
• stand, unassisted, by 10 and a one-half months, and
• walk, unassisted, by 12 months.

Yet many babies reach these milestones months earlier – or months after.

To know if your baby is on rail, y'all demand to know most the range of what'due south normal.

What'south the earliest you might await your baby to walk?

If your baby is tiresome, when should you be concerned about the possibility of a developmental delay?

And can parents practice to support healthy development?

Every bit nosotros'll see, a baby'due south environment — and personal quirks — affect the timing of motor milestones. Babies develop skills faster when nosotros encourage them to practice opportunities to exercise.

Hither is an overview of baby motor milestones, including the evolution of gross motor skills and fine motor skills. Throughout, I annotation ways in which parents tin influence development, and end with some evidence-based tips.

Gross motor milestones

Gross motor skills involve the large muscles of the legs, trunk, and arms. And when it comes to babies, pediatricians and developmental scientists are especially focused on vi of these skills:

• sitting up without support
• crawling
• standing with aid
• walking with assistance
• continuing without support
• walking without support

When can yous look your infant to achieve these motor milestones?

Every baby is dissimilar.

Some infants can sit up, unaided, by the age of 4 months. More half of all babies accept figured this out by 6 months. And about ten% of infants don't accomplish this particular milestone until they are 7.5 months or older.

Other motor milestones present an fifty-fifty wider range of timing. For instance, while the median age for learning to walk (unaided) is about 12 months, a few babies hit this milestone earlier the age of 9 months, and approximately 10% of babies don't begin walking without support until they are more than than 14.5 months former.

So if someone ever tries to sell you a chart of babe development "month by month," run the other way. That's but not how information technology works.

A better way to visualize the development of motor skills is to recall in terms of developmental windows – fourth dimension periods during which approximately 98% of babies can be expected to achieve a given milestone. Here's an infographic I made to illustrate – -adapted from a figure published by the Globe Health Organization (WHO 2006b).

As you can meet, some gross motor milestones tend to occur earlier than others, but the windows are wide, and they overlap each other. The resulting flick doesn't predict when your baby will hit any particular milestone – not in any fine-grained sense. Simply it provides us with a realistic time range.

If a infant's evolution seems wearisome, when should you be concerned?

Commencement, trust your intuitions. If, for any reason, you realize that you are concerned – whether or not y'all retrieve you "should" exist – talk to your pediatrician. If it turns out that your baby is having problems, early intervention tin can make a big divergence.

Second, if you lot're wondering about cutoff dates for achieving a given milestone, go along in mind: It depends. It depends on what other signs your baby is showing, and whether your baby has whatsoever known risk factors for a developmental problem.

But in the absence of any other concerns, a good rule of thumb is to pay attending to the 90th percentile – the age by which 90% of babies have accomplished a given milestone (Sice 2007).

If your infant hasn't reached a milestone past this date, consult with your pediatrician. Being slower doesn't mean that your child has a developmental delay. Merely information technology'southward a sign that your baby'due south progress should be reviewed and monitored.

The previous chart doesn't provide data well-nigh percentiles, so I'm going to add it hither:

What about the order of motor milestones? Is there something incorrect if a baby seems to skip a step, or experiences a reversal?

Not necessarily. Babies don't always hit these milestones in the same society, and one of the milestones – crawling – isn't fifty-fifty universal.

If you look at our graphics, you might reasonably presume that your baby will hit gross motor milestones in the following sequence:

(ane) sitting up without support; (2) crawling on hands and knees; (3) standing with assistance; (four) walking with assist; (5) standing without support; and (half dozen) walking without support.

And indeed, when the World Health Organisation (WHO) tracked the evolution of babies in 5 countries (Ghana, India, Kingdom of norway, Oman and the U.s.a.), this design was found in the largest percentage of infants – about 42% of them.

But more than a third of the babies achieved milestone #3 (continuing with assistance) before they crawled. Almost 9% of the babies also hit milestone #4 (walking with assistance) before crawling.

Another 10% of babies mixed the guild up in even more exotic ways, and approximately 4% of babies never crawled on their hands and knees (WHO 2006a).

Other studies have reported even higher rates of babies who never crawled — babies who were good for you and went on to walk inside the normal time window.

Then at that place isn't a principal sequence of motor development milestones that all babies follow. Every bit motor development experts Karen Adolph and John Franchak (2016) explain:

"The milestone charts advise an orderly, age-related march through a series of stages, but developmental pathways can differ and individual infants exercise not strictly attach to the normative sequence derived from average onset ages. Infants can learn skills in various orders, skip stages, and revert to earlier forms."

Why is there so much variation?

Some of it is cultural.

For example, in some African countries, parents actively train their babies to sit down, stand, and walk. They provide infants with lots of do, and this appears to accelerate the evolution of upright posture (Super 1976; Bril and Sabatier 1986; Karasik et al 2015; Adolph and Robinson 2015).

The notion is supported past experimental work.

Newborn babies take a "stepping reflex": If you concord a baby so that soles of his feet brush against the ground, the babe will spontaneously take steps — long before the baby is capable of standing under his own weight.

The reflex usually disappears over time, merely not if babies are given daily opportunities to practice the activeness, and such babies have reached the milestone of walking (without assistance) at an before age (Zelazo 1983).

So we've got evidence that parenting practices can speed up the step of motor development. And the antipodal is likewise true: Parenting can slow information technology downwardly.

In places where parents adopt a hands-off approach – or actively forbid babies from moving around during the day – infants have longer to achieve certain motor milestones (WHO 2006b; Mei 1994; Adolph and Robinson 2015; Adolf et al 2018).

What well-nigh crawling? Environmental factors play a large role there, too.

In places like the United States, parents look babies to clamber, and they provide them with opportunities to do so. Just this isn't true everywhere, and it probably wasn't truthful for our hunter-gatherer ancestors.

Crawling outdoors – in a globe inhabited past predators – wouldn't take been a skillful idea, and indeed, contemporary hunter-gatherers don't encourage their infants to crawl.

As I explain in this guide to the opens in a new windowdevelopment of crawling, information technology's non unusual for babies to reject easily-and-knees crawling in favor of other methods of getting effectually – similar scooting effectually on their bottoms, or rolling from place to place.

And it'due south clear that motor milestones are influenced by genetics.

When researchers have controlled for the effects of civilization and parenting, they've found that genetic factors have an important impact on the timing of motor milestones (Smith et al 2017).

Siblings don't achieve motor milestones at exactly the same fourth dimension, even if they are raised under similar conditions. Private differences in temperament, torso fat composition, and other characteristics — characteristics influenced by genes — can affect a baby's activity patterns, leading some babies to spend more fourth dimension practicing developing motor skills.

What nigh other motor milestones?

Holding objects

Two-month-former babies tin hold onto minor objects – if nosotros place these objects directly into their hands. And they are likely to bring the items up to their mouths to investigate (Rochat 1989).

But the grasp of a immature babe isn't very secure or reliable. When babies arms flail around, they are probable to lose their grip on whatever they are holding.

Learning to reach for – and firmly grasp – objects

Betwixt the ages of 4 and six months, most babies will have developed the manual dexterity to concord onto and shake a toy. They are besides developing the power to move an objects dorsum and forth between easily.

Babies tin can successfully reach for a stationary object, merely their movements are hasty, and babies aren't yet good at catching a moving object. Babies don't even so understand how to grasp large objects efficiently – they don't show a preference for doing it with both hands.

Between vi and ix months, these skills amend considerably. Babies become proficient at catching hold of moving objects. For example, they can grab rolling balls, and estimate when some assurance are rolling too fast to catch (van Hof et al 2008). By eleven months, babies also show amend planning for picking up big objects – they consistently reach with both easily at once (Fagard and Jacquet 1996).

Fine motor command and tool apply

By 8 to ten months, nigh babies tin show off fine motor skills. They are developing the ability to grasp small objects between the thumb and alphabetize finger. Babies are usually able to beverage from a cup, and they are figuring out how to eat with a spoon.

Just their attempts are bad-mannered. If you provide them with a loaded spoon, they are likely to option information technology up by the bowl end – not the handle (McCarty et al 2001; van Roon et al 2003). Moreover, they will hold onto the spoon with a fist grip, not a precision (thumb-to-index figure) grip.

By fourteen months babies are more adept. They might still hold the spoon in a fist grip, but they've learned how to hold it by the handle (van Roon et al 2003).

And effectually this time – from 12 months onward – babies tin can use writing implements to draw random-looking marks and dots.

By xviii months, these efforts may go more than controlled and organized, and may include direct lines and zig-zags (Dunst and Gorman 2009). More complex drawings – of geometric shapes, and figures with identifiable features (like a blob creature with legs) – develop slowly, and may not appear until a child is 3 years former (Dunst and Gorman 2009).

Give your babe lots of "stomach time."

Equally I annotation in this article, information technology's clear that "tummy fourth dimension" is of import. Babies develop amend muscle control when they spend supervised time on their stomachs. Information technology's good for building neck strength, and it helps babies develop the ability to roll, crawl, and sit down up from a lying position (Kuo et al 2008).

Help babies exercise an upright posture.

We've also seen how parents tin support the development of sitting and standing. Practise sessions – where you help your baby adopt an upright posture by providing support with your hands – may speed up development.

Help babies accomplish and grasp.

Non surprisingly, babies learn faster when we provide them with opportunities to impact, hold, and reach for objects.

For example, in experiments using mittens and toys covered in Velcro®, babies every bit immature every bit 3 months have gotten extra practice handling objects that would usually be difficult to grasp. When parents encourage their babies to explore objects with such "viscid mittens," babies have shown long-term developmental benefits (Needham et al 2017; Libertus et al 2015).

Let babies blindside.

Information technology'southward noisy and obnoxious, but researchers call up that babies develop important motor skills when they grab onto an object and bang away (Kahrs et al 2012). Simply make sure the object is safe for your baby to apply!

Encourage free play – and brand yourself a visible, responsive, and non-bossy playmate.

Babies exercise more than – and spend more than time interacting with objects – when we provide them with the time and space to engage in free play (Adolf and Koch 2019). And babies benefit when we get down on the floor to collaborate with them.

More reading

For more information virtually babe development, see this opens in a new windowalphabetize to Parenting Science articles.

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References: Motor milestones

Adolph Grand. 2008. Motor and physical evolution: Locomotion. In Yard.Yard. Haith and J.B. Benson (Eds), Encyclopedia of babe and early childhood development, K.M. Haith and J.B. Benson (Eds), San Diego: Bookish Press, pp. 359-373.

Adolph KE and Robinson SR 2015.  Motor development. In R. 1000. Lerner (Series Eds.) and Fifty. Liben and U. Muller (Eds), Handbook of child psychology and developmental science: Vol. 2: Cerebral processes (7th ed.) New York: Wiley, pp. 114-157

Adolph KE and Hoch JE 2019. Motor evolution: Embodied, embedded, enculturated, and enabling. Annual Review of Psychology, lxx, 141-164.

Adolph KE, Hoch JE, Cole WG. 2018. Development (of Walking): 15 Suggestions. Trends Cogn Sci. 22(8):699-711.

Bril B, Sabatier C. The cultural context of motor development: Postural manipulations in the daily life of Bambara babies (Republic of mali) International Journal of Behavioral Development. 1986;ix:439–453.

Dunst C., Gorman Eastward. (2009). Evolution of babe and toddler marking making and scribbling. Cent. Early on Learn. Lit. Rev. 2, one–xvi.

Fagard J, Jacquet AY. Changes in reaching and grasping objects of different sizes between vii and thirteen months of age. British Journal of Developmental Psychology. 1996;14:65–78.

Kahrs BA, Jung WP, Lockman JJ. 2012. What is the office of infant banging in the evolution of tool utilise? Exp Brain Res. 218(2):315-twenty.

Kuo YL, Liao HF, Chen PC, Hsieh WS, Hwang AW. 2008. The influence of wakeful decumbent positioning on motor evolution during the early life. J Dev Behav Pediatr. 29(5):367-76.

Libertus K, Joh As, Needham AW. 2016. Motor preparation at iii months affects object exploration 12 months later. Dev Sci. 19(6):1058-1066.

McCarty ME, Clifton RK, and Collard RR. 2001. The beginnings of tool use by infants and toddlers. Infancy 2: 233-56.

Mei, J. 1994. The Northern Chinese custom of rearing babies in sandbags: implications for motor and intellectual development. In: vanRossum, J.; Laszlo, J., editors. Motor development: Aspects of normal and delayed development. Amsterdam: VU Uitgeverij.

Needham AW, Wiesen SE, Hejazi JN, Libertus K, Christopher C. 2017. Characteristics of brief pasty mittens training that lead to increases in object exploration. J Exp Child Psychol. 164:209-224

Nelson EA1, Yu LM, Wong D, Wong HY, Yim L. 2004. Rolling over in infants: age, ethnicity, and cultural differences. Dev Med Child Neurol. 46(10):706-9.

Rochat R 1989 Object Manipulation and Exploration in two- to v-Calendar month-Old Infants  Developmental Psychology 25 (6): 871-884

Sices L. 2007. Use of developmental milestones in pediatric residency training and exercise: time to rethink the significant of the mean. J Dev Behav Pediatr. 28(1):47-52.

Smith 50, van Jaarsveld CHM, Llewellyn CH, Fildes A, López Sánchez GF, Wardle J, Fisher A. 2017. Genetic and Environmental Influences on Developmental Milestones and Movement: Results From the Gemini Cohort Study. Res Q Exerc Sport. 88(4):401-407.

Super CM. 1976. Environmental effects on motor development: the case of "African baby precocity". Dev Med Kid Neurol. 18(v):561-vii.

vam Hof P, Kamp J, Savelsbergh GJP. 2002. The relation of unimanual and bimanual reaching to crossing the midline. Child Dev. 73:1353–1362.

van Roon D, van der Kamp J, Steenbergen B 2003. Constraints in children'south learning to utilize spoons. In: Savelsbergh Thou, Davids K, van der Kamp J, Bennett SJ, eds. Evolution of Movement Co-ordination in Children: Applications in the Fields of Ergonomics, Health Sciences and Sport. Routledge, London: 75-93.

WHO Multicentre Growth Reference Study Group. 2006a. Assessment of sex activity differences and heterogeneity in motor milestone attainment amid populations in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl. 450:66-75.

WHO Multicentre Growth Reference Report Group. 2006b. WHO Motor Development Study: windows of achievement for six gross motor development milestones. Acta Paediatr Suppl. 450:86-95.

Zelazo PR 1983. The development of walking: New findings and sometime solutions. Periodical of Motor Beliefs 15: 99-137.

Image credits for "Motor milestones"

title paradigm of baby doing the plank past Doug LeMoine / flickr

image of mother helping baby walk by opens in a new window1000 Harsha / flickr

paradigm of infant holding plastic eggs past opens in a new windowmliu / flickr

image of baby drawing with chalk by opens in a new windowQuinn Dombrowski / flickr

charts (adapted from WHO 2006) copyright Parenting Scientific discipline

content final modified 6/2019

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Source: https://parentingscience.com/motor-milestones/

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