The study involved Year Two students in two classes at one primary school in Sydney,
New South Wales, Australia. Both classes received 16 lessons. The two classes of students aged
between seven and eight years were recruited and randomly assigned to either the plyometric
(experimental) or comparison (control) group. Randomisation was conducted at the class level.
The lead researcher randomly assigned one class to the plyometric group and one class to the
comparison setting before beginning the study. The treatment group consisted of 31 students (16
male, 15 female), who engaged in the plyometric activities at the start of their PE practical
lesson, while the comparison group consisted of 30 students (15 male, 15 female) who attended
their regular PE practical lessons. The study design and intervention are addressed in the
Methodology Chapter. All lessons covered knowledge and understanding outcomes from the
‘Game and Sport’ strand and Moving Skill outcomes in the NSW PDHPE Syllabus (BOS NSW
2013).
1.8 Delimitations of the Study
• Year 2 students from a Catholic Primary School, aged seven years to eight years formed all the test population.
33 1.9 Limitations of the Study
• Testing of students was restricted to primary school hours to avoid minimising the number of students available for testing and thus variance amongst the subjects.
• The student’s physical activity levels and types outside the PE lesson were not controlled. • The intervention addressed only the initial phase (eight weeks) of plyometric activities in
primary school health and PE students aged seven to eight. Accordingly, the results of
this research do not provide insight into long-term plyometric activity adaptations, nor
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Chapter Two – Literature Review
2.1 Introduction
Despite the well-known psychosocial and physiological benefits of participation in
physical activity (Erickson et al., 2019; Prakash, Voss, Erickson, and Kramer, 2015), recent
evidence consistently demonstrates that children and adolescent participation in physical activity
is not optimal (Active Healthy Kids Australia, 2018; Bardid, Rudd, Lenoir, Polman, and Barnett,
2015; Guthold, Stevens, Riley, and Bull, 2020; New South Wales Audit Office, 2012; Okely and
Baur, 2010). An integral element associated with the activity behaviours of children is their
proficiency in motor performance skills (Barnett et al., 2009; Hume et al., 2008; Jaakkola, Yli-
Piipari, Huotari, Watt, and Liukkonen, 2016; Lacourse, Turner, Randolph-Orr, Schandler, and
Cohen, 2004; Robinson et al., 2012; Ungerleider, Doyon, and Karni, 2002; Wall, Xu, and Wang,
2002). ‘Motor performance skills’ is a universal term used in this thesis to reflect various terms
previously used in the research literature (i.e. motor performance, fundamental movement/motor
skill, and fundamental sports skills) to explain goal-directed human movement. An inadequate
foundation in motor performance skills is possibly associated with a theoretical ‘proficiency
barrier’ (Seefeldt, 1982), whereby low-motor performance may result in lower levels of health-
enhancing physical activity and health-related fitness later in life (Stodden et al., 2009).
During childhood, motor performance skill development is an opportune time to make
worthwhile improvements from appropriate training interventions (Chaouachi et al., 2014;
Giblin, Collins, MacNamara, and Kiely, 2014). A relevant setting to accomplish this
development is during primary school PE. PE has been identified as an ideal setting to assist
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physical activity behaviours (Hensch, 2005; Ito, 2004; MacNamara, Collins, and Giblin, 2015;
Rosengren, Savelsbergh, and van der Kamp, 2003).
In Australia, the development of motor performance skills is an integral component of the
Health and Physical Education K-6 curriculum (Australian Curriculum Assessment and
Reporting Authority, 2018; NESA, 2018). Despite this, researchers have demonstrated low and
decreasing levels of motor performance skill proficiency that is concomitant with the growing
trends in children being overweight and obese (Cliff et al., 2012; Hardy, Barnett, Espinel, and
Okely, 2013; Moliner-Urdiales et al., 2010; Ogden, Carroll, Curtin, Lamb, and Flegal, 2010;
Okely and Booth, 2004; Robinson et al., 2012; Runhaar et al., 2010; Tester, Ackland, and
Houghton, 2014). The decreasing physical activity levels may be due to many children missing
out on adequate engagement in a variety of motor performance skill enhancing activities early in
their primary school years (Barnett et al., 2016). PE programs can provide opportunities that
engage students in meaningful activities that specifically enhance motor performance skills. An
area of inquiry that has illustrated some promise in enhancing children’s motor performance
skills is plyometric activities (Harries et al., 2012; Johnson et al., 2011).
Plyometric exercises are classified as a type of resistance training commonly used in
competitive and elite sports to improve an individual’s overall performance through enhanced
neuromuscular performance, muscular power, stretch-shortening cycle and rate of force
production (Kubo, Kanehisa, Kawakami, and Fukanaga, 2001; Lloyd et al., 2013). Plyometric
training has also been noted as a significant contributor to motor performance skills such as
jumping (Hammami, Gaamouri, Suzuki, Shephard, and Chelly, 2020; Kotzamanidis, 2006;
Morgan et al., 2013; Stodden, True, Langendorfer, and Gao, 2013). Meta-analytic studies have
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muscular power and motor performance skills in the sport setting (Behringer, Vom Heede, Yue,
and Mester, 2010; Faigenbaum et al., 2009; Falk and Tenenbaum, 1996; McKay and Henschke,
2012; Payne, Morrow, Johnson, and Dalton, 1997). These benefits are due to physiological
changes, such as improved stretch-shortening cycle, increased neuromuscular activation,
improved rate of force development and coordination, rather than muscle hypertrophy (Guy and
Micheli, 2001; Kraemer and Newton, 1994; Morgan et al., 2013; Naughton, Farpour-Lambert,
Carlson, Bradney, and Van Praagh, 2000). These aforementioned physiological changes have
also been associated with enhanced motor performance skill (Aagaard, Simonsen, Andersen,
Magnusson, and Dyhre-Poulsen, 2002; Faigenbaum et al., 2009).