The effect of a child-specific high intensity games intervention on physiological responses in normal weight and obese children : submitted by Nicole Westrupp to Massey University Wellington as a thesis towards the degree of Master of Health Science with Sport and Exercise Science (February, 2013)
To date, little is known about the use of child- specific high-intensity games- based exercise to improve body composition, cardiovascular indices, musculoskeletal health, psychological and social well-being. Past research in children has predominantly focused on the effect of laboratory or games based moderate intensity exercise interventions on the aforementioned markers of health (Janssen & LeBlanc, 2010). Therefore, the aim of this investigation is to assess the effect of a 6 week high-intensity games-based intervention on the physiological responses and physical parameters in normal and overweight or obese children aged 8 to 10 years. Twenty eight children were randomized into an exercise group (EX; 9.3 ± 0.9 y, 1.40 ± 0.10 m, 41.0 ± 12.4 kg, 20.5 ± 4.4 kg·m2) and 27 children into a control group (CON; 9.3 ± 0.8 y, 1.40 ± 0.09 m, 39.0 ± 11.3 kg, 19.5 ± 4.1 kg·m2). All participants completed two, pre-intervention (pre-INT) exercise tests on a treadmill i) discontinuous graded exercise test (GXT) to peak oxygen consumption (O2peak) and ii) a submaximal exercise test at running speeds equivalent to moderate (ventilatory threshold [VT]) and heavy (40% delta [difference between O2peak and VT]) intensity exercise for a total of 6 minutes. The EX group took part in 2 x 40 minute high-intensity child-specific games-based exercise sessions per week for 6 weeks. Follow-up assessments identical to the pre-INT were completed thereafter for all participants. The EX group from pre to post intervention (post-INT) demonstrated a significant increase in absolute O2peak and running speed for the GXT test (P < .05); and demonstrated a significant increase in their running speed at VT (7.8 ± 0.9 vs. 8.2 ± 0.8 km·h-1) and 40% delta (9.4 ± 1.0 vs. 9.9 ± 1.1 km·h-1; P < .05) when compared to the CON group. A significant decrease in O2 at VT and 40% delta was also observed for the EX group in comparison to the CON group (P < .05), thus demonstrating an improvement in exercise efficiency. In conclusion, a short duration (6 week) child-specific high intensity games intervention may improve maximal functional capacity and exercise efficiency, independent of body mass in children aged 8 to 10 years. An increase in the oxygen carrying capacity of blood, and capillary and mitochondrial density within the skeletal muscle are potential mechanisms for the aforementioned outcomes. Findings from this study provide important information concerning the practical application of physical activity within school or clinical-based programmes to improve health and physical fitness.