ECH130 Lecture Notes - Lecture 4: Active Transport, Repetitive Strain Injury, Passive Transport
29 May 2018
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Week 4 Lecture 1
• Do not associate physical activity with weight loss
o PA is in the context of health benefits and fun, promoting positive
health
• High value placed on lean/athletic body types and explicit reference to
weight loss strategies can contribute to eating disorders
What is Physical Activity?
• PA refers to the entire range of body movements.
• Physical activity is usually classified as follows: light, moderate and vigorous
• When there is minimal physical activity, the classification is sedentary
behaviour (sitting and not moving very much).
Changes in PA during the early years:
• Major developmental changes during the first 12 years of life. NOTE the
dramatic changes in movement patterns in the first two years (problem
solving, reflex movements etc.).
• It is important for teachers to understand movement patterns and allow as
many opportunities for unrestricted movement as reasonably possible e.g.
restraining devices
• Challegig hildres oeets is essetial to their deelopet.
Physical Activity vs. Skilled Action:
• Physical activity is not the same as skilled action
o Active children are more likely to acquire skills due to greater
opportunities and possible interest.
• In general, physical activity refers to the quantity or amount of movement.
• Skilled action refers to the quality of movement.
METs:
• MET = Metabolic Equivalent of Task.
• These are used to measure energy expenditure of activities.
• 1 MET is the equivalent of sitting down quietly
• Light activities are between 1 and 3 METs
• Moderate activities are between 3 and 6 METs (brisk walking, riding a bike)
• Vigorous activities are over 6 METs (when you no longer can talk to someone
whilst exercising) e.g. sprinting
Physical Activity Guidelines:
• Generally the amount of phsycial acitivty per day is expressed in terms of the
amount of Moderate-Vigorous Physical Activity (MVPA) per day.
o In other words, the amount of time per day 3+ METs.
• For adults, this time is often continuous e.g. long walks and bike riding.
• For children, activity often occurs in short bursts
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• Consolidation of MVPA into continuous periods increases from infancy to
adolescence.
Active or Sedentary?
• Amount of physical activity receives the most attention, but researhcers are
revealing increasing amounts of evidence that excessive sedentary time is an
INDEPENDENT RISK-FACTOR for cardiovascular health
• For children, excessive sedentary time generally comes from:
o Screen time (TV, computers, electronics)
o Passive transport (rapid decrease in number of Australian children
who walk or cycle to school)
Physical and Sedentary Guidelines:
Age
Daily recommendation for physical activity
Sedentary (apart from
sleep)
Infant
(0-1
year)
Not specified, but recommended to position
infants to allow for physical activity.
No more than 60
continuous minutes.
1-5
years
at least 3 hours per day. Includes light,
moderate and vigorous activity. Accumulate
throughout the day in free play.
Avoid extended sedentary
time such as watching tv,
passive transport (cars,
strollers).
5-12
years
at least 60 minutes of moderate- vigorous
physical activity per day. (Some researchers
argue that this recommendation should be
revised to 60 mins outside of school time.)
No more than 2 hours
sedentary time e.g.
computer/TV, homework.
Examples from adults to think about children:
• Under daily sedentary recommendation – equal or over daily activity
recommendation is ideal, under daily recommendation = if an adult could
convert some light activity tasks to moderate
• Over daily sedentary recommendation – equal or over daily activity
recommendation needs to build in reminders to take breaks from screen
time tasks, under daily activity recommendation = most difficult to change
and applies to a large percentage of the Australian population – change
should be gradual if it is to be sustained
o Sedentary time is often considered in terms of cardiovascular risk. However,
Straker et al (in press) also found other disadvantages
o E.g. strains from prolonged periods in awkward postures when
playing computer games or playing piano.
o On the upside, children who engage in a lot of these types of activities
generally have better motor skills
Occupied and Meaningful PA:
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