Exercise as it relates to Disease/The effect of high-intensity progressive resistance training on adiposity in children

This page is a critique of the article 'The effect of high-intensity progressive resistance training on adiposity in children'

What is the background to this research?
Obesity has become one of the most prevalent concerns in the 21st century, increasing at an alarming rate. Ten per cent of the world’s school-aged children are estimated to be carrying excess body fat, a quarter of them classified as obese. These children are likely to stay obese into adulthood and are at greater risk of developing non-communicable diseases such as diabetes and cardiovascular diseases. The rising levels of childhood obesity can be attributed to by decreased levels of physical activity and modern diet changes of increased energy-dense foods which are high in fat and sugars but low in micronutrients.

Research has been done on Progressive resistance training (PRT) in adults and how it has been shown to reduce adiposity, reduce insulin resistance and improve glycemic control in adults. However, there are limited studies regarding PRT as an isolated intervention in children with adiposity as the primary outcome. It is essential to understand the differences between the physiological aspects of children and adults, children should not be seen as miniature adults as they are unique and have singular traits at each phase of growth.

Where is the research from?
A C Benson, M E Torode & M A Fiatarone Singh from The University of Sydney conducted this research on rural New Zealand school students. Professor Maria Fiatarone Singh is a Geriatrician with an interest to improve the care of older adults in medical practice, to prevent and treat frailty and functional decline. She has published extensively in the fields of exercise, nutrition, ageing and has assisted with several research projects on exercise and the effects it has on reducing adiposity.

What kind of research was this?
The conducted study was a randomized controlled trial of the effects of PRT on adiposity in children. Randomized control studies allow for reduced bias, as it balances out individual characteristics between groups. The goal of randomization is to improve the chance that the research groups are representative of the general target population. The use of a control group aims to prove any significant findings were the cause of the outcome variable being studied.

What did the research involve?
78 participants with at least 7-10 years at intermediate or high school were randomly selected and assigned to either the PRT or no-treatment wait-list control group. The PRT group trained twice per week for 8 weeks, completing two sets, eight repetitions per set, for each of the 11 exercises using free weights and ankle weights. The 11 exercises were split into 5 upper body exercises, 4 lower body exercises and 2 abdominal exercises. Rating of perceived exertion (RPE) 6-20 scale was used to determine training intensity and progression.

The primary outcomes measured were:
 * Central adiposity (estimated via waist circumference)
 * Bioelectrical impedance (BIA) fat mass
 * Body mass index (BMI)
 * 1 repetition maximum bench press and leg press
 * Blood analysis (lipids, insulin, glucose, estimated insulin resistance and peak oxygen consumption)

The use of Borg’s RPE scale as a means of prescribing exercise intensity and examining participants adherence to the high-intensity program was a methodical choice, Borg’s RPE is an affordable, practical and valid tool for monitoring and prescribing exercise intensity, independent of gender, age, exercise modality, physical activity level and CAD status.

What were the basic results?
Waist circumference was significantly improved (reduced) in the PRT group compared to an increase in the controls, all whole body estimates of body fat decreased with PRT compared with an increase in the controls, muscle strength significantly increased relative to the control group, increase in HDL-cholesterol approached statistical significance and other metabolic parameters and aerobic capacity did not change over the 8 weeks. The change in waist circumference in the whole cohort was greatest in those with the greatest upper body strength gains and decreases in body mass and fat mass was greater in those with the greatest increases in fat-free mass. As cardiorespiratory fitness remained unchanged, this suggests that the changes were driven by the anabolic exercise itself.

What conclusions can we take from this research?
The main conclusion that can be drawn from this research is that 8 weeks of high-intensity PRT is a feasible and effective method of reducing central adiposity and improving body composition and strength in children without the aid of dietary intervention. If exercise were to be combined with dietary intervention, however, it has been shown to result in weight loss and substantial improvements in metabolic profile over dietary intervention alone.

Practical advice
It is imperative to intervene in any stage of excessive weight gain especially at during the youth of an individual as it is likely the weight gain will carry over to their adulthood, an excessive amount of adiposity puts an individual at greater risk of developing non-communicable diseases , and this paper shows that PRT alone is effective in aiding fat loss. As long as the individual finds the intervention easier to adhere to, making a choice from aerobic training, resistance training or a diet plan matters little as long as an effort is being made to reduce weight and or adiposity.

Further information/resources
Strength training for kids: https://kidshealth.org/en/parents/strength-training.html Obesity in children: https://www.betterhealth.vic.gov.au/health/healthyliving/obesity-in-children-causes Tips to help children maintain a healthy weight: https://www.cdc.gov/healthyweight/children/index.html