Chia, Michael

The health consequences of physical inactivity among youths are worrisome as sedentary lifestyles among youths become entrenched. Obesity rates among youths in Singapore are about 10%, but there are concerns that this rate is not sustainable over the longer term. Physical activity (PA) prevalence data in Singaporean youths are mixed as questionnaire data show adequate levels of PA engagement while HR monitoring data show very low levels of PA, in research employing single methods to capture the data. The study purpose of was to compare PA data garnered from questionnaire and HR monitoring in Singaporean youths. 280 youths aged 10-15 years, and of normal body weight, completed a Physical Activity and Exercise Questionnaire and wore HR monitors (Polar Vantage, NV) for 10 hours to gauge PA consumption over two weekdays and a weekend. Questionnaire responses revealed that 41% of primary school participants and 38% of secondary school participants experienced moderate-to-vigorous PA. HR data, over the weekday and weekend, on the contrary, showed that 86-94% of primary school participants and 94-99% of secondary school participants did not experience any moderate-to-vigorous PA (HR 140-159; HR >160 bpm). Both questionnaire and HR data showed no sex difference in PA engagement but HR data showed that younger youth were less sedentary (HR<120 bpm) than older youth. Younger youth aggregated 24 minutes and older youth aggregated 10 minutes at HR 140- 159 and HR>160 bpm on the weekday. No vigorous PA (HR>160 bpm) was detected in participants on the weekend. In the best case scenario, PA engagement in Singaporean youths met only 40% of the recommended aggregation of 60 minutes of, at least moderate intensity PA, advocated by the Ministry of Health (MOH) in Singapore and others. Schools can play a significant part in discouraging sedentary behaviour and encouraging physical activity behaviours via holistic and coordinated intervention programmes targeted at all youths.

Obesity has reached global epidemic proportions over the past 10 years. As countries become more affluent, their populations tend to adopt caloric balance problems that have plagued the USA and Western Europe. Obesity is classified as the second most serious reversible health problem, after smoking in the world today. The relationship between obesity and cardiovascular diseases is well documented. The increase in obesity in Asian countries is remarkable. In 2004, the prevalence of obesity in the adult population in Singapore increased upto 16% (high risk category: ≥ 27.5kg/m2) and prompted many forms of government action, encouraging collaboration between businesses, the educational system and non-governmental organizations. This paper reviews the rise of obesity in Singapore and some of the approaches being implemented to address this concern. Singapore, a multiethnic country, with Chinese, Indian and Malay populations, has to address diversity in customs, diet and religions to combat obesity. The collaborative efforts of various organizations such as the Ministry of Health (MOH), Ministry of Education (MOE) and the Health Promotion Board (HPB) have successfully improved the health status of Singaporeans. The fact that the rise in obesity in Singapore is lower than in other neighboring Asian countries attests to the partial success of the collaborative efforts.

The aim of the study was to compare between girls and women, the recovery of Wingate Anaerobic Test (WAnT) power after two prior sprints of 15 s duration with a short active recovery interval in-between the sprints. Participants with written informed consent were 19 girls (age: 13.6±1.0 yrs; body mass: 51.2±7.6 kg and stature: 1.59±0.06 m) and 21 women (age: 25.1±2.7 yrs; body mass: 57.9±7.7 kg and stature: 1.61±0.05 m). Lower limb muscle mass was determined using a dual-energy x-ray absorptiometric (DXA) procedure. Following a standardised warm-up, each participant completed a series of three 15 s WAnTs, with each test separated by a 45 s active recovery interval. WAnT power variables were computed over 1 s time periods and were corrected for the inertia of the cycle ergometer (Monark 834E). Whole blood lactate concentrations (BL) were obtained immediately post warm-up and at three minutes after the completion of the third WAnT. Peak power (PP), expressed in watts per lower limb muscle mass (W·kg-1LLMM) were significantly greater in women than in girls in the frrst 15 s WAnT (46.1±10.9 vs. 37.4±2.3 W·kg- 1LLMM, P<0.05). However mean power (MP) over the first test was not significantly different between the girls and women (33.8±2.1 vs. 34.7±5.9 W·kg-LLMM, P>0.05). Girls were better able to replicate their power achieved in the first WAnT, in the third WAnT than women (mean of the differences±standard deviation of the differences for PP: 84±47 W vs. 174±84 W; MP: 81±45 W vs. 161±65 W, P<0.05). Despite the better recovery in WAnT power in girls during the third 15 s cycle sprint, BL taken at post- warm-up (2.5±0.5 vs. 1.9±0.5 mM·L-1, P>0.05), and at three . min post exercise (9.2±1.2 vs. 8.4±1.3 mM·L- 1, P>0.05) were not significantly different in girls and women.

Repeated sprint exertions are common in team sports and more sedentary adults are pursuing team sports on a recreational basis. The values of the mass exponents in allometric scaling of functional exercise capacities are fundamental to the accurate interpretation of changes in physiologic parameters during exercise, with exercise training. Apparently, the effect of fatigue on allometrically-derived mass exponents in relation to power output generated during all-out intensity repeated sprints in sedentary adults is not understood. The aim of the study was to establish if acute exercise fatigue caused by repeated sprint efforts affected the value of the derived b or mass exponent in allometric scaling of power in sedentary adult subjects. Twenty male and female sedentary adult subjects performed four 10-s all-out intensity sprints on a non-motorized treadmill (NMT), on three separate sessions with the rest intervals between each sprint at 60-s, 90-s or 120-s, respectively. A dual energy X-ray absorptiometric (DXA)-determined lower limb muscle mass (LLMM) was the best body size descriptor for 1-s peak power (PP), derived from the NMT. Results showed that the b exponents in relation to PP were altered (range 0.87-1.58) in repeated sprints that were separated by different rest intervals. It was necessary to establish beyond sample-specific mass exponents, a trial-specific mass exponents in the allometric scaling of all-out intensity repeated sprints in sedentary adult subjects, for appropriate comparisons in NMT-derived PP that was size independent and dimensionless.

The study investigated the muscle power of the lower limbs in a group of 13 and 14 year old boys and girls. Participants were 45 boys (stature: 1.69±0.05 m; body mass: 57.9±11.8 kg; lower limb muscle mass: 16.4±2.5 kg) and 36 girls (stature: 1.59±0.06 m; body mass: 57.7±7.6 kg; lower limb muscle mass: 12.5±1.2 kg). Lower limb muscle mass (LLMM) was determined using a dual energy X-ray absorptiometric (DEXA) procedure. Participants completed a 30 s Wingate Anaerobic Test (WAnT) where peak power (PP) and mean power (MP) were expressed in relation to LLMM using ratio-scaling and log-linear adjustment procedures. Boys and girls had similar body mass-accounted PP (37.7 vs. 37.6 W/kg, P>0.05) and MP (28.0 vs.33.7 W/kg, P>0.05) when ratio-scaled to LLMM, or when the same data were log-linearly adjusted for PP (495W vs. 488W, P>0.05) and for MP (423W vs. 422W, P>0.05) in relation to LLMM. However, common b exponents that defined the allometric relationship between PP and MP, and LLMM in both boys and girls were 1.26 (SE 0.15), and 1.21 (SE 0.15), respectively. These were markedly different from the b exponent of 1.0 used in the ratio standard, or the 0.67 value predicted from geometric similarity theory. Despite a similar interpretation of data (i.e. no sex difference in lower limb muscle power in boys and girls) using either allometric modeling or ratio-scaling, expressed in relation to LLMM, allometric modeling of sample-specific exercise data is recommended to produce an appropriate size-independent variable, to allow appropriate comparisons in performance between boys and girls. Data in the study showed no sex difference in WAnT power expressed in relation to LLMM in adolescent boys and girls.

Inadequate hydration before, during and after exercise puts the safety and well-being of Singaporean youths at risk especially when sports training and Physical Education (PE) lessons are conducted outdoors, under the hot and humid weather conditions of Singapore. The study examined the exercise knowledge of youth athletes in Singapore schools: 586 youth athletes from four primary schools, four secondary schools and one junior college. All participants completed a validated exercise hydration knowledge quiz that was developed based upon the consensus statements and position stands of two international sports associations. An average knowledge score of 44.7±14.0% (range 0–87.1%) was obtained, which was significantly below the minimum competence score of 80%. Post-exercise hydration knowledge was lacking when compared to pre-exercise and during-exercise hydration knowledge. Overall, exercise hydration knowledge gaps were identified, in particular for post-exercise hydration; still the majority of participants from all schooling levels did not attain the competence score of at least 80%. Coach education and PE training programmes should specifically target and ameliorate these knowledge deficiencies to empower youth athletes to take personal responsibility for their safe participation and training in sports.

Singapore, a developed city state of four million people is experiencing the pitfalls that come with rapid modernisation and economic progress-elevated disease risk factors among adults and young people. Weekly compulsory physical education classes of 70 minutes in schools and the associated sports activities after classes are inadequate to meet emergent physical activity guidelines of a daily accumulation of at least 90 minutes of physical activity of at least moderate intensity. Daily play sessions that are exclusive of an active daily recess, physical education classes taught by trained specialists and after-school sport sessions, can provide many developmental and holistic health benefits that may carry over into adulthood. A school environment that is play-encouraging, play-enabling and play-inviting can be a useful, innovative and natural way of inculcating a love for movement and help redress a serious trend of physical activity insufficiency while youngsters engage electronic gaming activities. Pilot initiatives for the PRIDE (personal responsibility in daily effort) for PLAY (participation in lifelong activity for youths) programme is a radicalised approach in a number of primary schools in Singapore to infuse daily physical play of between 20 to 45 minutes during curriculum hours. The hope is that PRIDE for PLAY will reap benefits of improved holistic health of youngsters- better physical, social, emotional and mental attributes. While PRIDE for PLAY is no panacea to all of the ills of modernisation, it will go some way in helping the students of tomorrow to be physically healthy, socially more engaged and tolerant of others, mentally more apt to problem solve and emotionally more proficient to embrace working life in adulthood.

An investigation was done to determine the acceptability of the Lactate Pro LT -1710( blood lactate analyser while using a multiple-tester approach by assessing its accuracy, consistency, reliability and validity by comparing it to the YSI 2300 STAT PlusTM as the reference blood lactate analyser. The study was conducted in three phases separated seven days apart. The participants (n=9) completed the Bruce protocol on the motorised treadmill in the phase 1 and 2 and an all-out 30 s sprint on the non-motorised treadmill in the third phase. Pre and post-exercise capillary blood samples were collected from the finger-tip of the participants. Blood lactate data for all the three test days were pooled to determine the overall comparative agreement between the two analysers over a range of blood lactate values 0-16.2 mmol.L-1). A significant and high correlation was obtained for the combined pooled data (r=0.994, p<0.05). The ratio limits of agreement for pooled pre-exercise, pooled post-exercise and combined data were 00400.91, 0.61-0.84 and 0.53-0.90 respectively indicating the consistency of the blood lactate analysis by the Lactate Pro 1710(r) over a range (1-16.2 mmol.L-1) of blood lactate values. This study found the Lactate Pro 1710 blood lactate analyser to be acceptably accurate, consistent, reliable and valid to be used under varied exercise and training situations, especially when multiple testers are likely to be involved in the analysis.

The aims of this study were to investigate the effects of training status, different intensities, durations and modes of exercises on the activity of complement receptor type 1 (CR1) of erythrocytes. Fifteen sedentary male adults and 15 male adult endurance athletes performed five separate treadmill exercise trials: max VO2 test (T1), exercise at 40% max VO2 for 30 min (T2), 80% max VO2 for 30 min (T3) and for 60 min (T4) and downhill running (-10% gradient) at 60% max VO2 for 30 min (T5). Blood samples were taken before exercise, immediately, one h, two h and 24 h after each exercise trial to assay the activity of erythrocyte CR1. The results showed that there was no significant difference between trained and untrained participants in erythrocyte-tumor cell rosette (ETCR) formations at rest (p>0.05). ETCR was significantly decreased after five exercise trials (p<0.05). Changes in ETCR were more obvious after T1, T3 and T4. ETCR 24 h after T5 was significantly lower than that after uphill running. Greater reductions and slower recoveries in ETCR were found in the untrained group than in the trained group. The results indicated that erythrocyte CR1 activity at rest was not affected by training status, but was significantly inhibited by acute exercise. Exercise at higher intensities and longer durations resulted in a greater suppression in the activity of erythrocyte CR1. The suppression was more marked in the untrained participants than in the trained participants. Downhill running induced a longer delay in recovery in erythrocyte CR1 activity compared to uphill running.

This study aimed to determine verbal memory performance differences between obese and normal-weight adolescents among high academic achievers as measured by a computerised version of Rey Auditory Verbal Learning Test. 58 normalweight and 47 obese adolescents were recruited from two Secondary Schools (aged 13 to 16 years) and one Junior College (aged 17 to 18 years) in Singapore. Eight trials of word recall and memory test scores, the sum of total number of words correctly recalled for Trials 1 to 5 [Total Learning (TL)], and difference in word recall between Trial 5 and Trial 1 [Learning Rate (LR)] were measured. Socioeconomic status (SES) was measured by the summative ranking of the housing category and the educational levels of the parents. Obese participants recalled significantly lesser words in all trials and TL memory category. There was no significant difference between normal-weight and obese participants on the indicators of housing category, father’s education, mother’s education, overall SES, and LR memory category. Obese adolescents had poorer verbal memory performance as compared to the normal-weight participants. The role of SES could not adequately account for the memory difference between both groups. This finding suggested difficulty in memory acquisition and retrieval ability in the obese group.