On MY Way

Physical Development

Children in the middle years are steadily growing. It is important to remember, however, that physical changes occur at different ages and rates, and can differ greatly among children. This is particularly true between ages 9-12.53, 54, 55 There is a clear link between good physical health and good physical development during these years, and good nutrition and exercise are critical to children’s overall development.


During the middle years, most children experience a rapid growth spurt, both in height and weight. For girls, the growth spurt tends to occur between ages 9-13 typically starting at 10 and peaking at 12 years of age. For boys, it generally happens between ages 11-15 with a peak at age 14. During this time, children can grow between five and eight centimetres and gain as much as 2.75 kilograms in a year.56 In general, girls gain more weight and height during this time period than do boys. This growth marks the beginning of adolescence, and sex-related differences start to become more evident.57

Strength and endurance

In the early middle years, children tend to have limited muscular endurance, and there is no significant difference in the physical abilities of boys and girls. Starting at age seven, children’s muscular strength increases slowly and steadily until age 13 to 14 in boys, and age 12 in girls. Boys, however, also experience an acceleration in strength development during the growth spurt stage that does not occur in girls.58

It is important to remember that any strength building activities should take into account the readiness of the child’s bones, muscles, nervous system and joints to handle load-bearing exercises.59

Children's Artwork


Around age seven, the physical precursor to puberty occurs, when genes associated with reproductive behaviour and sexual differentiation are activated and changes to bodily hair, skin and sweat glands begin to occur.60 Puberty itself generally occurs between the ages of 10 and 12 for girls. For boys, it usually occurs after the middle years, between ages 12-14. However, these ages can vary greatly.61

In puberty, children undergo a growth spurt, develop gender characteristics, become fertile and experience increased curiosity about human development, including changes in the body. There are changes in both physical appearance and behaviour,62 with increased interest in romantic relationships63 and exploratory behaviour.64 As well, children’s notions of gender and their own gender identity become more solidified.65

Movement skills

The middle years are a critical phase in the development of motor (movement) skills. These skills are required for more than sports and recreation, and are critical for nearly all physical activities. They should be learned sequentially, based on the characteristics of the child. Skill development is less related to age than it is to growth and physical maturity, and is also associated with the environment in which a child is being raised.66

Early in the middle years, fundamental movement skills typically improve significantly. These skills include running, jumping, bending, twisting, throwing and kicking, and they should be mastered before children are able to develop more specialized skills. At this stage, children are typically able to perform these skills one at a time, but might have difficulty combining them. Gradually, they learn to combine various motor skills in sequence, and they can adapt them to various physical activities.67 Children with developmental disabilities may develop these skills in a different manner.

Fine motor skills are also developing during this time period.68 Fine motor skills involve the use of the small muscles in the fingers, hand and arm to effectively manipulate tools and materials. Hand-eye coordination is an important component of this development and requires a child to use their vision to control the movements and actions of their small muscles. As children enter the middle years, they continue to enhance their fine motor skills and their drawing, writing, colouring and scissoring skills become more fluid and adept.69

During the middle years, there is a need for children to become more independent in self-care tasks, productivity and leisure. All of these tasks require the development and application of skilled hand-eye coordination and the ability to use two hands when each hand is doing something different than the other. Examples of self-care skills that are developing during the middle years include:

  • dressing independently (doing up zippers, buttons and snaps)
  • using forks and knives
  • completing morning and evening routines (e.g., tooth brushing)
  • tying shoelaces
  • managing backpacks and lunch containers
  • using scissors
  • keyboarding and using a computer mouse
  • learning to play a musical instrument
  • making art/crafts

Health knowledge and behaviour

Understanding and taking responsibility for good health

It is important for children in their middle years to begin understanding the factors that contribute to healthy growth and development. They also need to start taking responsibility for and playing a role in their own health and wellbeing.

Health literacy

It is important that children have the skills and knowledge that are essential for maintaining and improving their own health. These skills and knowledge are referred to as “health literacy”.70, 71 As children develop and gain health literacy, they begin making better choices when it comes to food and drink, lifestyle, and safety.

Health literacy includes mental health. Increasing mental health literacy promotes wellness and knowing the signs and symptoms of mental illness. Those with high levels of mental health literacy are better able to identify the strengths and needs in themselves and others and are more equipped and empowered to seek help. In addition, those with high levels of mental health literacy report lower levels of mental health stigma.72

For children in their middle years, developing health literacy requires support from family, at school and in the community.76 Parents and caregivers, in particular, can support children by modelling healthy choices related to eating, substance use, relationships, personal care, mental health and injury prevention. Families that select foods and prepare healthy meals together help children develop food literacy skills and reinforce healthy eating habits. Likewise, parents and caregivers that acknowledge and care for their own mental health help children to develop positive habits related to their mental wellness.

For Indigenous children, the use of traditional medicine can be a mechanism for wellbeing, and may be used to maintain good health.77 Indigenous ways of knowing include a recognition that achieving balance across spiritual, emotional, physical and social spheres of life is essential to safeguarding health and wellbeing. Indigenous spiritual wellness is grounded in cultural connections, and so for Indigenous children in the middle years, participation in cultural learning and activities can inspire healthy choices and healthier living.

Canada’s Food Guide for First Nations, Inuit and Métis reflects the values, traditions and food choices of Indigenous people. For Indigenous families and communities, sharing food together is an important part of cultural learning and connection. For Inuit children and families, promoting opportunities to access and share country food has been identified as a fundamental component of healthy community development.78

Lower levels of physical activity in children are associated with poor health, including obesity and Type 2 diabetes, and reduced motor skills.73 Greater physical exercise in middle childhood is related to better brain functioning, cognitive skills and academic performance, including attention, memory, processing speed, mental adaptability and self-control.74, 75

For Indigenous children, physical activity often involves transmitting cultural traditions, and land-based activities practices.79 This could include activities such as cultural camps, building fires, swimming, chopping wood and traditional games.80 It has been recognized that “physical activity is cultural activity” and that these acts support wellbeing.81

Participation in physical activity

Children in their middle years need to maintain a healthy, active lifestyle. Most Ontario children in their middle years are not getting the recommended daily physical activity of 60 minutes of moderate to vigorous exercise, as well as vigorous muscle and bone strengthening activities at least three times a week. The need for more physical activity is even more essential for children with physical challenges, illness or disabilities, who may not reach the recommended levels because of their different abilities. It is important that parents, caregivers and other caring adults find ways of making physical activity meaningful and enjoyable for all children in the middle years, as this will increase the chances that they stick with these activities, develop good physical fitness, and remain physically active throughout their life.

Successful efforts to increase physical activity emphasize lifelong physical activity, the benefits of the outdoors and nature, and the importance of relaxation and having fun with family and friends. Ideally, such efforts should emphasize being physically active at various times throughout the day. They should also mix organized and unorganized activities, and address barriers to physical activity, such as the challenges faced by children with special needs.82

Experience and connection with the natural world provides children with dynamic developmental, social and cultural opportunities. Connection to nature has an impact not only on physical development, but also on social and emotional development. The value of going on the land and having a connection with the natural world and wild spaces has long been recognized by Indigenous cultures, but is equally relevant and beneficial for all children. Studies have shown that spending time in nature helps with recall and memory, problem-solving, and creativity, in addition to the benefits to physical health.83

For Indigenous children, spending time in the living world, including time with plants and animals and thinking about Creation stories allows the children to emotionally connect with their culture.84

Children's Artwork

Parents/caregivers and play

Parents and caregivers have an important role to play in supporting their children’s healthy physical development. Parents and caregivers can increase children’s activity levels by reducing the family’s sedentary time, promoting active play and time outdoors as an alternative to screen time, and planning for and spending time with children in physical activities. Acting as a role model for children is important; children who perceive at least one of their parents or caregivers to be physically active are more likely to meet physical fitness guidelines. The children who are physically active with their families are more likely to continue to be active as adults.85

Organized play

It has long been recognized that participation in organized sport, recreation and physical fitness yields tremendous benefits. For example, involvement in physical fitness is associated with reduced body fat and a lifetime of exercise and good health.86 Many children in Canada participate in organized sports, with higher participation rates among boys, children with parents/caregivers involved in sports, children in smaller cities or towns, and children of Canadian-born parents and caregivers.87, 88 Research shows a troubling trend that girls tend to drop out of organized sports and fitness as they get older,89 demonstrating that more work is needed to create and support gender inclusive opportunities for participation.

Nutrition and healthy weights

In addition to physical activity and exercise, good nutrition and a healthy body weight are critical to healthy physical development. Nutrition and healthy weight is supported by access to adequate, affordable, fresh, nutritious food. The effects of unhealthy weights, such as high blood pressure and insulin resistance, can affect children’s cognitive skills, including memory, brain processing speed and verbal skills. There are a number of factors in the physical and social environments of children that can contribute to weight gain. These include poor eating habits and overeating, high-calorie drinks, lack of physical activity, toxic stress, inadequate or poor quality sleep, mental health challenges, too much screen time, and eating away from home.90


There is increasing recognition that the quantity and quality of sleep that middle years children are getting has a great impact on their physical and mental health.91 Ideally, children in the middle years should get nine to 11 hours of uninterrupted sleep per night.

Research indicates, however, that one-third of children have trouble falling asleep and staying asleep at least some of the time, and one-third are classified as sleep deprived.92 Children with histories of stressful or traumatic experiences may have neurologic differences in sensory processing and self-regulation that may cause disturbances in sleep. Also, children with perceptual sensitivities to sound, light, or touch are more likely to have difficulty filtering these out at night. It is also thought that screen time and the presence of screens (e.g., phones) in bed, especially just before bedtime, have contributed to sleep problems. Bedtime access to and use of media devices is associated with an inadequate amount of sleep, poor sleep quality and excessive daytime sleepiness. Children who sleep less also tend to be less active. Conversely, exercise has been found to improve sleep quality.93, 94, 95

Body image

Concern about body image can emerge early in some children. Starting at age six, some children report dissatisfaction with their bodies, and those feelings increase with age. The physical changes in the later part of the middle years have a significant effect on children’s sense of identity and body image.

Children at this age are becoming very aware of what others may be thinking, and as a result, some become more self-conscious about their bodies and how they compare to others. This increases through exposure to age inappropriate sexualized media content which is becoming more available and accessible to children online.96 All of this is happening at a time when children are experiencing a greater need for social acceptance, and some children develop anxiety about being accepted or rejected based on appearance. For girls in particular, interactions with their peers focus more often on appearance and physical comparisons,97, 98 and girls tend to become more dissatisfied with their bodies than boys.

Unfortunately, teasing about appearance is more common during this period and can have a significant influence on body image. 99, 100 Poor body image can contribute to depression, low self-esteem, eating disorders, risky sexual behaviour and children representing themselves in age inappropriate sexualized ways to others.101 However, friendships can protect against poor body image,102 and increased physical activity can also help to improve body satisfaction.103