A Narrative Review of Screen Time and Wellbeing among Adolescents before and during the COVID-19 Pandemic: Implications for the Future.

The COVID-19 pandemic has disrupted the lives of many. In particular, during the height of the pandemic, many experienced lockdowns, which in turn increased screen time drastically. While the pandemic has been declared an endemic and most activities have been reinstated, there appears to still be elevated screen time among adolescents due to poor habits formed during the pandemic lockdowns. This paper explores the factors by which screen time affects well-being among adolescents and how the pandemic may have influenced some of these factors. For example, beyond having greater screen time, many adolescents have also reduced their physical activities and picked up poor sleeping habits. These findings highlight the importance of having integrated activity guidelines that go beyond limiting adolescents' daily screen time. It is important to affirm that beyond ensuring that adolescents limit their daily screen time, they are also meeting physical activity and sleep guidelines so that they achieve a holistic sense of wellbeing.

Effects of a 12-week exercise training programme on aerobic fitness, body composition, blood lipids and C-reactive protein in adolescents with obesity.

INTRODUCTION: Developing effective exercise programmes for the paediatric population is a strategy for decreasing obesity and is expected to help in eventually limiting obesity-associated long-term health and societal impact. In this study, the effects of a 12-week twice weekly additional exercise training, which comprised a combination of circuit-based resistance training and aerobic exercises, in additional to typical physical education sessions, on aerobic fitness, body composition and serum C-reactive protein (CRP) and lipids were analysed in 13- to 14-year-old obese boys contrasted with a control group. MATERIALS AND METHODS: Both the exercise group (EG, n = 12) and control group (CG, n = 12) participated in the typical 2 sessions of 40-minute physical education (PE) per week in schools, but only EG participated in additional 2 sessions per week of 45 to 60 minutes per session of exercise training, which comprised a combination of circuit-based resistance training and aerobic exercises maintained at 65% to 85% maximum heart rate (HRmax = 220 - age). Body composition was measured using dual energy X-ray absorptiometry (DEXA). Fasting serum CRP and blood lipids were analysed pre- and postexercise programme. Aerobic fitness was measured by an objective laboratory submaximal exercise test, PWC170 (Predicted Work Capacity at HR 170 bpm). RESULTS: Exercise training significantly improved lean muscle mass, body mass index, fitness, resting HR, systolic blood pressure and triglycerides in EG. Serum CRP concentrations were elevated at baseline in both groups, but training did not result in a change in CRP levels. In the CG, body weight increased significantly at the end of the 12-week period. CONCLUSION: This study supports the value of an additional exercise training programme, beyond the typical twice weekly physical education classes, to produce physiological benefits in the management of obesity in adolescents, including prevention of weight gain.

Reliability of power output derived from the nonmotorized treadmill test.

There is limited evidence that the nonmotorized treadmill (NMT) test is able to elicit peak power (PP) and mean power (MP) reliably for high-intensity and short-duration exercises in untrained adults. This study aimed to establish the intra- and intersession reliability of PP and MP derived from the NMT test. Nine untrained men and 9 untrained women participated in the study. They completed 2 sessions of a 10-second NMT test on 2 separate occasions that were scheduled 2 weeks apart (intersession test). Each session consisted of 2 sprints (intrasession test). On the third session, the subjects performed two 30-second Wingate Anaerobic Tests. Inter- and intrasession power measurements were analyzed using repeatability coefficient, typical error, coefficient of variation, change in the mean, and Pearson correlation coefficient. Inter- and intrasession measurements using these statistical tests all showed high reliability of the results. The study clearly showed that PP and MP measurements derived from the NMT test was just as reliable as the current "gold standard."