Course:KIN355/2020 Projects/Through centre of gravity

From UBC Wiki

Force creation and stability at the time of projection

Defining the Concept and Its Importance

The centre of gravity in a body is a hypothetical point around which most of the weight of the body is concentrated and equally distributed (Hamilton, 2011). The point about which most of the weight of the human body is concentrated continually changes as a human typically changes their position often. Hence, to accommodate for the changes in position and the consequent adjustment of weight distribution in the body, the centre of gravity changes continually as well. The centre of gravity is an important concept that plays a role in achieving stability. For example, the lower the centre of gravity in the body is towards the base of support, the greater the stability will be (Bredin, 2020). Likewise, the more in the middle of the base of support that the centre of gravity lies, the greater the stability (Bredin, 2020). In the context of childhood movement experiences, if a child experiences the concepts of stability, like centre of gravity, and learns about it through the use of his or her own body, the child will understand the advantages of understanding the concepts surrounding stability and may be more effective at applying these skills when playing sports, or other real life activities (Bredin, 2020).

Stability is an individual’s capability to maintain a stationary position or perform purposeful movements while resisting the force of gravity (Bredin, 2020). The ability to maintain stability is necessary to proficiently perform all activities of daily life and important to perform other fundamental movement skills (Mickle et al, 2011). An inability to achieve and master stability during the early childhood can hinder the capability of performing more complex movement skills like running or jumping and increase the risk of a child sustaining injury during sports participation (Mickle et al, 2011). Moreover, regaining stability after losing it is the basis for achieving agility (Bredin, 2020). As mentioned earlier, it is clear that the position of the centre of gravity affects the amount of stability of a body. Therefore, by understanding the concept of the centre of gravity in relation to stability, early childhood educators, teachers, or grassroots coaches may use this knowledge to promote stability in children by teaching them positions of the body that have the greatest amount of stability, and how to reposition the body to these positions that allow stability. This would consist of explaining the centre of gravity concept in terms and activities understood by children, which would allow for a mastery of stability and the ability to master more complex movement skills.  Hence, it is important for children and others to understand the concept of the centre of gravity to maintain stability and thus have the ability to master more complex movement skills.

Role in Childhood Development and Contemporary Considerations

Acquiring fundamental and more complex movement skills are crucial characteristics of the development of the child and the proficient performance of movement. Acquiring these skills largely rely on being able to achieve and maintain stability (Mickle et al, 2011). The centre of gravity and its relative position in the body have a direct effect on the ability to maintain stability, and thus also has an effect on proficient performance of movement and the acquisition of movement skills. It has been found that in a study conducted with a cohort of high school basketball players, individuals who suffered from ankle injuries had poorer stability scores (Mcguine, 2000). Poor stability may actually predispose an individual to injury (Mcguine, 2000). Therefore, a lack of stability increases one’s risk for injury and hinders proficient performance of movement skills. Another study has found a positive correlation between performance of fundamental movement skills and stability skills in children with Down's Syndrome (Capio et al, 2017). In their study, children who had better stability skills tended to have more proficient fundamental movement skills (Capio et al, 2017). This indicates a direct link between stability and the acquisition of fundamental movement skills in these children. Moreover, there has also been found to be a positive relationship between better performance of gross motor skills and greater muscular strength, and a greater stability (Wang et al, 2012). Based on this research, stability directly affects the acquisition of fundamental movement skills and the proficient performance of movement. Hence, the centre of gravity which directly affects stability also affects proficient performance of movement, in turn. The acquisition of fundamental movement skills and proficient performance of movement is crucial for the healthy development of a child. These aspects can be achieved through stability and understanding of the centre of gravity.

Nowadays, children and teens in Canada spend almost 2 out of every 3 hours that they are awake being sedentary. Moreover, school aged children have an average screen time of 6 to 8 hours in a day (Alberta Health Services, 2020). This is a problem because less time is being spent outdoors while being active, which gives children less time to discover their body, learn to maintain stability, and learn other fundamental and more complex motor skills. With prolonged screen time and computer use, individuals usually position themselves in a way wherein they can see the computer/screen with ease. This usually involves the head moved forward and the spine curved, known as the forward head posture or turtle-neck posture (Kang et al, 2012). With regular screen use, like nowadays, children’s bad posture can become a habit. If this were to happen, bad posture can cause the spinal cord to change shape, which directly affects stability (Hughes, 2019). Therefore, prolonged screen time affects stability through the habit of bad posture and a lack of activity, wherein children do not get as much of a chance to discover concepts like centre of gravity contributing to maintaining stability as they discover their movements and bodies. Being active and going outdoors should be encouraged and even mandated in school. This could allow children to move around, play, and discover their bodies and possible movements they can make. In turn, this would facilitate the discovery of body movements and postures that promote stability, thus increasing understanding of stability and the underlying concept of the centre of gravity.

Children with Down’s syndrome have stability deficits, and therefore face a delay in the development of fundamental movement skills (Capio et al, 2017). Coaches and teachers need to be aware of this and make necessary adjustments to physical activities for these specific children. Although children with Down's syndrome do reach motor milestones, it is delayed, and noticing children of a similar age acquire milestones could take a toll on children's self esteem. Coaches and teachers can make certain adjustments to make sure to prevent the self esteem of the children from going down. Hence, they need to be aware of the effects of having Down's syndrome. It is important for the children to be active, although they make take a longer duration, than other children of their age, to understand concepts surrounding movement and stability.

Practical Applications

Activity Recommendation 1

Example of a Balance Board. (From UBC Wiki media archives)

Title: Balance Board Basketball

Purpose: To develop balance by learning how to “accommodate for the changes in position and the consequent adjustment of weight distribution in the body”, as mentioned above, through the use of a balance board. The balance board (or other balancing trainer such as a BOSU® trainer that provides an unstable surface to stand on) that the participant is standing on will force them to maintain a position through their centre of gravity in order to not fall off the board. This will help them develop their sense of balance through their centre of gravity (Yaggie & Campbell, 2006). With help from coaches and educators, children will slowly begin to get a sense of the, “positions of the body that have the greatest amount of stability” once again as mentioned above, such as a bent knee stance which lowers their center of gravity, increasing their stability.

Target Age: Ages 6 and above

Apparatus:

-       Necessary: A basketball, 2 balance boards (or equivalents), cones

-       Optional: Coloured bibs

Environmental Space/Set-up: Any sized area works as long as the ground allows for a basketball to bounce. A wooden or rubber padded floor is recommended as children will most likely fall multiple times. To set-up, a balance board is placed on either side of the play area and is surrounded by cones in a 4-foot radius.

Instructions: Players are divided equally into 2 teams and assigned one half of the court. One player from each team is designated as the hoop and must go to the other side of the court and stand on the balance board, trying their best not to fall. The game then starts with the same broad rules of basketball; a play starts with the referee throwing the ball up in the air in the centre of the court between too players and the player who catches the ball gets control, players must then bounce the ball to move, if they stop bouncing the ball, they must pass to their teammates and players from the opposing team can steal the ball mid bounce.

The aim of the game is to score as many points as possible by dribbling the ball towards your team’s “hoop player” on the other side of the court and then passing the ball to them from outside the cone parameter. A point is scored if the hoop player catches the ball without taking a foot off the balance board or falling off it.  

If the “hoop player” fails to maintain balance through their center of gravity and steps off the balance board, a point is not scored, and the basketball is returned to the centre of the court and another play is started.

Modifications: Changes are easy to make, if children are finding it very easy to score points, you can increase the radius of the cones so that children will have to use more force to pass the ball to the “hoop player” leading to more inaccuracy and an increased need for the “hoop player” to maintain balance while reaching to catch the ball. The size of the basketball can also be increased or decreased based on the age of the children and so can the stability of the balance board by widening or narrowing it, making it easier or more difficult to maintain balance through the centre of gravity.

Activity Recommendation 2

Title: Hopscotch

Figure 1

Purpose: To aid in the development of balance through the centre of gravity in children while in a forward motion. As highlighted in the work by Maïano et al. (2019), hopscotch is especially useful as a physical activity intervention to develop balance in children with Down’s Syndrome which is important considering children with Down’s Syndrome have a delay in balance development (Wang & Ju, 2002).

Target Age: 5 – 12, according to the British Columbia Ministry of Education (2006)

Apparatus: Chalk, shooter (bean bag, pebble or any other small item that can be thrown and wont roll)

Environmental Space/Set-Up: Hopscotch works in almost any area, all you need to do is draw out the play area. The basic setup is to draw out and number the layout in Figure 1 on the floor with chalk and place the shooter at the start.

Instructions: Children line up in front of the play area- and take turns throwing the shooter at the consecutive numbered squares. If the shooter lands and stays within the square, the player must hop on all the squares in ascending order, except for the square the shooter is in, till they reach the final square. They must then turn around and hop all the way back to the square the shooter is in, pick up the shooter and return to the start. This is one turn. If a player misses the targeted square with the shooter, they hand the shooter to the next player in line and goes to the back of the line.

Figure 2

Once the player has completed a turn, the player must then try to throw and get the shooter to land on the next numbered square, which in this case would be 2, and so on and so forth, following the same steps above, avoiding the square the shooter is in while hopping. When a player hops on a square that has no squares next to is such as 1, 4, 7 and 10 according to Figure 1, the player must hop on a single foot. On squares 2 & 3, 5 & 6 and 8 & 9 the players plant both their feet in both squares simultaneously.

Modifications: The rules can be modified extensively. If children are finding it hard to balance on one foot, you can allow children to hop on two feet for the entirety of the hopscotch play area. To increase difficulty and increase training in maintaining balance through the centre of gravity, you can increase the distance between squares, or edit the layout of the board completely such as in Figure 2. These modifications will make it harder for the children to maintain their centre of gravity as they have to jump further distances and in different directions.

You could also, add tasks within the squares for example in Figure 2, when you land on square 7 you must turn around 360 degrees while hopping on one foot. Or when you land on square 11, you must continue hopping on your left foot.

Summary

The center of gravity in the human body refers to a hypothetical point in which the weight of the body is concentrated and distributed equally. This hypothetical point varies from one person to another depending on their physiques and position. It is important for early childhood educators to understand this concept and its effects on balance and stability, as they’re necessary for the acquisition of various movements and daily tasks. By incorporating balance and stability activities, children can practice their fundamental movement skills, master more complex movements, and avoid negative consequences such as poor posture.

References

  1. Active Children. (n.d.). Retrieved October 20, 2020, from https://myhealth.alberta.ca/Alberta/Pages/sedentary-behaviour-guidelines.aspx
  2. Bredin, S (2020). Module 4.2: Developing Fundamental Movements. KIN 355 Movement Experiences for Young Children, School of Kinesiology, University of British Columbia
  3. British Columbia Ministry of Education. (2006). Physical Education K to 7 Integrated Resource Package 2006. BCED. http://www.bced.gov.bc.ca/irp/pdfs/physical_education/2006pek7.pdf
  4. Capio, C. M., Mak, T. C., Tse, M. A., & Masters, R. S. (2017). Fundamental movement skills and balance of children with Down syndrome. Journal of Intellectual Disability Research, 62(3), 225-236. doi:10.1111/jir.12458
  5. Hamilton, N., Weimar, W., & Luttgens, K. (2011). Kinesiology: Scientific Basis of Human Motion, 12e. Retrieved October 19, 2020, from http://accessphysiotherapy.mhmedical.com/content.aspx?bookid=965
  6. Hughes, A. (2019, March 07). Anna Hughes. Retrieved October 20, 2020, from https://screentimelabs.com/is-excess-mobile-device-use-harming-your-childs-posture/
  7. Kang, J., Park, R., Lee, S., Kim, J., Yoon, S., & Jung, K. (2012, February). The effect of the forward head posture on postural balance in long time computer based worker. Retrieved October 20, 2020, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3309315/
  8. Maïano, C., Hue, O., Lepage, G., Morin, A. J., Tracey, D., & Moullec, G. (2019). Do exercise interventions improve balance for children and adolescents with Down syndrome? A systematic review. Physical therapy, 99(5), 507-518.
  9. Mcguine, T. A., Greene, J. J., Best, T., & Leverson, G. (2000). Balance As a Predictor of Ankle Injuries in High School Basketball Players. Clinical Journal of Sport Medicine, 10(4), 239-244. doi:10.1097/00042752-200010000-00003
  10. Mickle K. J., Munro B. J., Steele J. R. (2011). Gender and age affect balance performance in primary school-aged children. J. Sci. Med. Sport 14 243–248. 10.1016/j.jsams.2010.11.002
  11. Wang, H., Long, I., & Liu, M. (2012). Relationships between task-oriented postural control and motor ability in children and adolescents with Down syndrome. Research in Developmental Disabilities, 33(6), 1792-1798. doi:10.1016/j.ridd.2012.05.002
  12. Wang, W.-Y., & Ju, Y.-H. (2002). Promoting Balance and Jumping Skills in Children with down Syndrome. Perceptual and Motor Skills, 94(2), 443–448. https://doi.org/10.2466/pms.2002.94.2.443
  13. Yaggie, J. A., & Campbell, B. M. (2006). Effects of balance training on selected skills. The Journal of Strength & Conditioning Research, 20(2), 422-428.
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