Down Syndrome Developmental Milestones and Physical Activity

Developmental Milestones in Children with Down Syndrome[edit | edit source]

From the time a child is born, they grow and learn at their own pace. However, some skills are expected to be mastered around a specific age. These are called developmental milestones. Milestones can be physical achievements, language-related, or social accomplishments.[1]

The ability to move is essential to human life and development. All children begin developing a wide range of movement skills, or motor skills, starting at birth. These motor skills are wide-ranging and often broken down into the sub-sections below:

DS Motor Skills.png

Persons with Down Syndrome (DS) will generally achieve the same basic motor skills necessary for everyday living and personal independence, however, it may be at a later age and with less refinement compared to those without DS.[2] Some adjusted milestones for DS are available below:


While these milestones are generally agreed upon, studies targeting developmental milestones tend to only examine a small number of people. This makes the information less representative of the entire DS population. Researchers also commonly compare people with DS to their non-DS counterparts of the same age. This is an invalid comparison, and it would be more correct to compare children with DS to non-DS individuals of the same mental age. Despite these limitations, the above-listed milestones are widely used and considered accurate.[4]

Balance and Down Syndrome[edit | edit source]

It is common for children with DS to be delayed in reaching common milestones such as sitting independently, standing and walking. One of the contributing factors to the delay of these specific milestones is poor balance. Balance challenges often follow a child into their teen years and sometimes into adulthood.[5] Impaired balance may also impact the development of other motor abilities and cognitive development. Being able to maintain balance allows for exploration, social interaction and overall freedom.[6]

Understanding the underlying factors contributing to poor balance can help therapists plan individual interventions and strategies to enhance the quality of life of persons with DS. Some causes of balance difficulties are:

  • Ligament Laxity: This results in elastic/loose joints and a large range of movement, which can lead to instability and poor control.
  • Low Muscle Tone: characterised by the ‘floppy’ appearance of limbs, with little activity in the muscles at rest, which impacts static balance. This can improve over time but can influence balance greatly in the early years.
  • Slow Reaction Times/Speed of Movement: When a person with slow reaction times/speed of movement feels unsteady, it will take longer time for them react to this feeling, and once it is understood, the corrective movement will also be delayed.
  • Differences in Brain Size: Persons with DS typically have smaller cerebellums, which is a part of the brain that contributes to the control of balance. The small size impacts its function, limiting balance reflexes, and causing blurry vision when completing tasks at high speed. Other parts of the brain are also smaller, creating issues with voluntary activities, walking technique and coordination.
  • Poor Postural Control: Typically the posture of a person with DS is slouched - hunched over, with a rounded neck. This prevents the head and body from sitting over the pelvis. Posture is impacted by inaccurate messages being sent to the brain from the body’s sensory system. This leaves people with DS less capable of adapting or making anticipatory adjustments to changing environments.[6][7][8]

Optionally, learn more about Down Syndrome Developmental Milestones and Physical Activity on this page.

Strength and Down Syndrome[edit | edit source]

Another contributing factor to delayed milestones and a common challenge for individuals with DS is decreased strength.

During childhood, children with DS do not experience the same amount of muscle growth or strength increase as their peers without DS.[9] This is in part due to the decreased amount of physical activity experienced by people with DS, but it is also caused by unknown genetic reasons - the reason on these factors is ongoing. Regardless of the reason, persons with DS consistently fall behind in strength categories when compared to their peers without DS; individuals with DS typically have 40-50% less strength.[10]

Decreased strength can have a large impact on the lives of persons with DS. Not only can it impact activities of daily living, such as walking upstairs, getting out of a seat etc, but it can also lead to:

  • increased wear and tear on joints
  • higher risk of falls
  • elevated level of fatigue
  • delayed developmental milestones
  • increased risk of osteoporosis[11]

It can also contribute to reduced balance due to weakness of the stability muscles.[11]

Reduced Levels of Physical Activity[edit | edit source]

The research on physical activity levels in people with Down syndrome is conflicting. However, most research does find people with DS live highly sedentary lives and they do not achieve the recommended guidelines for physical activity levels.[12][13] The daily recommended levels of physical activity for children is at least 60 minutes of moderate to vigorous-intensity activity, and for adults the recommended levels is at least 150 minutes of moderate aerobic activity each week, including at least two strength session in the week.[14][15] Although people with DS may have decreased capacity for exercise compared to their peers without DS, the guidelines clearly state that children with DS should still meet the recommended guidelines or do as much physical activity as they can manage.[16]

Furthermore, as people with DS age, their physical activity levels fall even further behind their peers without DS.[12][17][18] This trend demonstrates that reduced activity levels are a lifelong issue for children with DS that must be addressed.

Barriers to Physical Activity[edit | edit source]

Most individuals with DS have to overcome social and environmental barriers to access physical activity. People with DS face many obstacles with the main barriers being lack of money, transportation, access to programmes and support from family and carers. It is commonly thought that people with DS are too fragile to participate in exercise.[19]

Poor strength and balance are limitations to both cardiovascular and resistance exercise. However, this needs to be addressed as many individuals with DS are now being classed as obese. Individuals with Down syndrome have been found to have substantially higher rates of obesity compared to the general population.[20] Often occurring early on in childhood, obesity was found to remain stable from childhood into adulthood, with slight increases after puberty.[21] Obesity is now recognised as a major health risk for people with Down syndrome.[22]

The causes of obesity in the Down syndrome population can be divided into physiological causes and behavioural causes. Physiological causes may include conditions such as hypothyroidism, decreased metabolic rate, increased leptin levels (a hormone which helps regulate hunger), short stature and low levels of lean body mass.[23] Behavioural tendencies such as negative thinking and inattention behaviour may become barriers that prevent vital dietary and lifestyle changes to occur.[23]

Shelly Obesity Picture.png

Physical inactivity also increases the chance for the development of other health problems such as diabetes, increased blood pressure, dyslipidaemia, early markers of cardiovascular disease, musculoskeletal disorders, breathing difficulties with worsening of sleep apnea and psychological effects including reduced quality of life [14][23].

Aerobic fitness in both youth and adults with Down syndrome is reduced compared to their peers without DS [24][25]. Studies find that adolescents and young adults with DS have comparable aerobic fitness to non-DS older adults (60years +) with heart disease [25]. They also have lessened aerobic abilities, reduced muscular strength and reduced bone mineral density levels by 26% compared to their peers without DS [26].

Benefits of Physical Activity[edit | edit source]

Overall, strong evidence suggests that regular physical activity can lead to numerous health benefits. Participating in physical activity has a positive impact on people’s health. Benefits include improved cardiovascular, metabolic, musculoskeletal and psychosocial health profiles in people with and without DS [27].

Shelly Physical Activity2.png

The fact that many children with DS reach Developmental Milestones later than their peers may be a contributing factor to lower levels of physical activity during infancy.[28] Onset of independent walking in children with Down syndrome occurs roughly 1 year later in comparison to children with typical development [29]. Earlier walking onset has been observed in infants with Down syndrome who performed greater amounts of high-intensity activity at 1 year of age [30]. Changes to physical activity levels in infants with Down syndrome has been suggested to encourage motor development, validating the importance of early physiotherapy intervention [28].

Some health benefits of increased physical activity levels in persons with DS are:

  • Decreased body fat percentage
  • Decreased body weight
  • Improved cardiovascular fitness
  • Improved muscle strength
  • Decreased depression
  • Reduced risk of osteoporosis[31][32][33][34]

In addition to the health benefits listed above, physical activity is important for people with DS because it:

  • Promotes the development of physical and social skills.
  • Establishes a regular routine around being physically active, leading to better habits in the future.
  • Increases life satisfaction.
  • Prevents secondary conditions associated with DS including diabetes, osteoporosis and dementia [35].

From the evidence, it is clear that physical activity is integral to a person with Down syndrome’s health, fitness and wellbeing [16].

Resources[edit | edit source]

References[edit | edit source]

  1. Sacks B, Buckley S. What do we know about the movement abilities of children with down syndrome. Down Syndrome News and Updates 2003;2:131-141. (accessed18 March 2018).
  2. Kim H, Kim S, Kim J, Jeon H, Jung D. Motor and cognitive developmental profiles in children with down syndrome. Annals of Rehabilitation Medicine 2017;41:97-103. (accessed 21 March 2018).
  3. National Down Syndrome Society. Down Syndrome Developmental Milestones. 2009. [Picture]. (accessed 12 March 2018).
  4. Frank K, Esbensen A. Fine motor and selfcare milestones for individuals with down syndrome using a retrospective chart review. Journal of Theoretical Social Psychology. 2015;89:719-729. (accessed 20 March 2018).
  5. Georgescu M, Cernea M, Balan V. Postural control in down syndrome subjects. The European Proceedings of Social and Behavioural Sciences. (accessed 17 March 2018).
  6. 6.0 6.1 Malak R, Kostiukow A, Wasielewska A, Mojs E, Samborski W. Delays in motor development in children with down syndrome. Medical Science Monitor 2015;21:1904-1910. (accessed18 March 2018).
  7. Costa A. An assessment of optokinetic nystagmus in persons with down syndrome. Experimental Brain Research 2011;8:110-121. (accessed17 March 2018).
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  10. Mercer V, Stemmons V, Cynthia L. Hip abductor and knee extensor muscle strength of children with and without Down’s syndrome. Phys Ther 2001;1318-26.
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