Research 7

Full paper accepted for publication in Journal of PE & Recreation (HK)

This study describes the associations between isokinetic leg strength and Wingate Anaerobic Test [WAnT] performance in young people. Twenty four girls (9.9±0.2y; 1.33±0.06m; 31.8±7.6kg) and 23 boys (10.2±0.3y; 1.38±0.05m; 33.5±4.2kg) with appropriate consent completed in random order, a 30s WAnT and three supramaximal reciprocal contractions of the knee extensors and flexors of each leg, at each randomly assigned velocity of 0.52 (30⁰) and 3.15 (180⁰) rad·s^-1, as part of a series of tests completed over three separate visits to the laboratory. Inertia-adjusted 1s peak power [ PP ] was higher in the boys than in the girls (267±45 vs. 220±58 W, p<0.05) as was mean power over 30s [MP] (192±34 vs. 168±41, p<0.05). Combined isokinetic leg strength ( extension plus flexion for both legs ), corrected for gravity was not significantly different between boys and girls at 0.52 rad·s^-1 (218±32 vs. 196±42 Nm, p >0.05), as at 3.15 rad·s^-1 (146±26 vs.132±38, p>0.05). Pearson Product Moment correlations between isokinetic leg strength and PP, and MP were significant (p<0.05) and higher in the girls than in the boys (r=0.81-0.89 in girls vs. r=0.45-0.53 in boys). When the analyses were re-run with body mass statistically controlled for, the strength of the associations between isokinetic leg strength and WAnT performance were reduced but remained significant in girls (r=0.56-0.70, p<0.05) but not in boys (r=0.30-0.43, p>0.05). These results suggest that isokinetic leg strength in girls explained a greater part of the variance in their WAnT performance than in boys. The greater power outputs generated by boys than the girls in the WAnT is not explained by the differences in isokinetic leg strength between the sexes at the two velocities tested in this study.

Research 8

Staff Development Fund, NTU/ Association of Commonwealth Universities, UK.

Full paper in Biology of Sport, 18: 45-53, 2001

 The aim of the study was to compare between girls and women, the recovery of Wingate Anaerobic Test Power (WAnT) after two prior sprints of 15-seconds’ duration with a short active recovery interval in-between the sprints. Subjects with informed consent were 19 girls (age:13.6±1.0yrs; body mass:51.2±7.6kg & stature: 1.59±0.06m) and 21 women (age:25.1±2.7yrs; body mass:57.9±7.7kg & stature:1.61±0.05m). Lower limb muscle mass was determined using a dual x-ray absorptiometric procedure. Following a standardised warm-up, each subject completed a series of three 15-second WAnTs, with each test separated by a 45-second active recovery interval. WAnT power variables were computed over 1-second time periods and were corrected for the inertia of the cycle ergometer (Monark 814E). 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 first 15s WAnT (46±11 vs. 38±3W.kg^-1LLMM, p<0.05). However mean power (MP) over the first test was not significantly different between the girls and women (35±6 vs. 34±23W.kg^-1LLMM, 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±47W vs. 174±84W; MP: 81±45W vs. 161±65W, p<0.05). Despite the better recovery in WAnT power in girls during the third 15s 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 minutes post exercise (8.4±1.3 vs.9.2±1.2 mM.L^-1, p >0.05) were not significantly different in girls and women. 

Research 9

Full paper accepted for publication in Journal of PE & Recreation (HK) 

The efficacy of the OTO Power Stretch apparatus in improving upper body muscular endurance and abdominal endurance was established in this study for a group of male and female adults. Results of the study demonstrated that participants increased their exercise endurance for the upper body and abdominal muscles significantly. Exercises using the OTO Power Stretch apparatus, done twice a day, over a training period of four weeks with thrice-a-week exercise sessions, can positively effect subcutaneous fat at the waist and abdomen in men, reduce body weight in men, reduce girth measurements in men, reduce hip girth in women, and increase upper arm and chest girth in women. 

Research 10

PEAK  V0₂ and Wingate anaerobic test data of Physical Education trainee teachers in Singapore and the validity of field aerobic and anaerobic performance tests

Chia, YHM, Wang, J. and Quek, JJ

Full Paper accepted for publication in Journal of PE & Recreation (HK)

The study provides exercise data on the aerobic (shuttle-run test) and anaerobic (stair-run test) field performances of physical education trainee teachers in Singapore and validity data on the field performance tests. Fifty subjects (22 female & 28 male) participated in the study. Male subjects were significantly (p<0.05) older (26.2±3.1 y versus 23.1±1.4 y), taller (1.71±0.07 m versus 1.61±0.06 m), heavier, (66.2±11.3 kg versus 51.4±5.1 kg) and had lower sum of four-site skinfolds (29±11 mm versus 38±12 mm) than the female subjects. They also had greater predicted oxygen uptake peak (48±5 versus 39±4 ml/kg body mass/min, p<0.05; ES=2.0) and peak power (16.8±2.6 versus 12.9±1.3 W/kg body mass, p<0.05; ES=2.0) than the female subjects. Differences in exercise performances were largely attributed to the differences in body composition between the sexes. The shuttle-run test and the stair-run test were highly correlated with the treadmill laboratory test (r=0.89, p<0.05) and the Wingate Anaerobic Test (r=0.77, p<0.05), respectively. Aerobic field performance was not correlated with anaerobic field performance (r=-0.1 for male, r=0.3 for female, both p>0.05). This study ameliorates the paucity of exercise data on PE trainee teachers in Singapore, and confirms the validity of field performance tests in assessing the exercise performance in this cohort of subjects.

Research 11

Applying exercise & health sciences in sports and physical education with regards to young people

Michael Chia

Full Paper accepted for publication in Journal of PE & Recreation (HK)

  Teachers of physical education and sports trainers must know that young people are not miniature replicas of adults and must therefore not be treated like adults. Young people are less equipped than adults to handle intense exercise of a short duration but they are better equipped than adults to handle intermittent-type activity as young people recover faster than adults from a previous exercise bout. Developing young people are responsive to muscular endurance training but regimens involving heavy weights should be avoided until they are in late adolescence. Training regimens introduced at the appropriate time as young people grow and develop will induce positive training-induced performance improvements of a similar magnitude to those documented in adults. However, a period of detraining of more than six weeks will cause many of these changes to gradually decay. There is only weak evidence to support the suggestion that training must be started early in order to experience success in sport as adults, and encouraging young people to specialise in sport at a young age may prove to be counter-productive. What is crucial is that the training regimens must offer young people meaningful experiences that they can internalise and make sense off rather than to have the goals and the objectives for the training to be imposed upon them.  PE teachers and sports trainers must realise that childhood success in sport is often linked to the rate of maturation-early maturing boys have a distinct advantage in most sports but with girls, it is often the late maturers who are more successful (e.g. gymnasts). Trainers and PE teachers must help young people to internalise the motivation to exercise (by making physical activity fun and rewarding) so that when the extrinsic motivation of the teacher or trainer is removed, they will carry on with exercise and stay physically active throughout adulthood. When young people are helped to understand the principles underlying fitness and health, and are taught how to develop and take ownership of their own training regimens that can periodically be appraised and modified as they get older or when their aspirations change, they will always remain grateful to the PE teachers or sports trainers who taught them well.

Research 12

Do differences in PEAK oxygen uptake in men and women explain recovery during intermittent exercise?

Michael Chia

Full Paper accepted for publication in Journal of PE & Recreation (HK)

The purpose of the study was to examine if differences in peak oxygen uptake between men and women explain their recovery from maximal effort intermittent exercise. 24 men (25.3±2.7yrs; 1.75±0.06m; 69.3±8.9kg) and 24 women (23.2±2.2yrs; 1.63±0.06m; 53.5±7.6kg) participated in the study. On separate occasions, participants completed a peak oxygen uptake (peak V0₂) treadmill test and five 20s cycle sprints, which were separated by a 45s recovery interval. Peak V0₂, PP and MP in the repeated sprints and blood lactate measurements were taken. Results showed that men had higher peak V0₂ than women (53.2±8.7 vs. 42.8±6.8 ml/kg BM/min, p<0.05), but there was no sex difference recovery of Wingate Anaerobic Test power between successive sprints when PP and MP in the sprints were expressed as a percentage of the highest attained in the first sprint (64-88% in men versus 67-90% in women). Differences in peak V0₂ between men and women did not explain the recovery of men and women during intermittent maximal exercise.

Research 13

Michael Chia

Full paper in European Journal of PE, 5: 231-258, 2000

This review critically appraises the anaerobic tests used to evaluate the exercise performance of young people (ages 8-18 years). It is tempting to speculate but present information about anaerobic performance tests do not allow researchers to state categorically which test best quantifies anaerobic performance in young people. None of the tests reviewed has enabled accurate measurement of all the different determinants of anaerobic performance. Consequently, the test of choice very much depends on the research question being asked, and importantly, on the characteristics of the subject cohort (i.e. physically able, disabled, healthy or diseased, young or elderly, etc.) being tested.  Researchers must be mindful that young people are not adults-in-miniature. Therefore in deciding on the appropriate test to use for assessing the anaerobic performance of young people, due attention must be given to issues of validity and reliability of the results elicited by the test. Among the tests which quantify peak anaerobic power, the vertical jump test is the least expensive to administer. However assumptions about the actual force generated and velocity in the ballistic task have to be made. Even when the jump protocol is standardised, it is still difficult to determine the actual muscle groups that contribute to the jump. By incorporating a force-platform, it is possible to determine the forces generated and also the resultant direction of the generated forces. The stair-running test is also easy and inexpensive to administer, but like the vertical jump, it is still difficult to ascertain the exact muscle groups which contribute to the performance. It appears that the force-velocity test is the method of choice for determining peak anaerobic power output and for studying the force-velocity characteristics of muscle during cycling. The test however, takes a longer time to complete and current data show an accumulation of blood lactate concentration between successive sprints, which may have a detrimental impact on power generation. Monoarticular isokinetic machines are expensive but can best determine peak torque and force-velocity relationships of single monoarticular contractions. Protocols however need to be standardised and calibration methods instituted. The equipment may also need to be modified when testing young people. Among the tests, which quantify local muscular endurance, treadmill sprinting yields the highest total work and large muscle mass is involved in the task. The method however requires several assumptions to calculate mechanical power, and it is also difficult to determine which muscles contribute to the exercise. The main disadvantage of the test is that young people are often afraid to push themselves to full capacity because of the fear of tripping. The use of a non-motorised treadmill may alleviate this fear to some extent but young people need to be adequately habituated to the relatively novel task. Equipment is also expensive and modifications are necessary to take into account the horizontal and vertical forces that are generated as well as the system inertia of the non-motorised treadmill. The tests of choice to quantify both anaerobic power and local muscular endurance of the legs are cycle protocols which last 30- to 60 seconds. There are isokinetic as well as isotonic (more appropriately, isoinertial) protocols. The former requires expensive ergometers but they provide useful information about force-velocity relationships. Among the latter, the Wingate Anaerobic Test (WAnT) is the most popular and has been evaluated more extensively than any other anaerobic performance test. The test requires less sophisticated equipment and can be modified to yield more precise data by increasing sampling frequency of the pedal motion, and taking into account the inertia factors of the ergometer in the computation of power. One argument about the WAnT is that the 30-second test is too short to maximise anaerobic ATP yield. There are however arguments to the contrary. Longer protocols, result in a higher aerobic contribution to the test, have low subject compliance and require lower applied forces, which may not optimise peak power outputs.  

Research 14

Michael Chia

Full Paper accepted for publication in Journal of PE & Recreation (HK) 

Exercise data show that young people’s capability to perform exercise tasks of a maximal intensity lasting between one and 90 seconds, are lower than that of adults. In general, the maximal intensity exercise performance of young people improves with age and level of biological maturity but further research that involve larger samples of boys and girls, over the entire maturity range are needed to supplement the sparse database. Data of girls are notably lacking. More research is needed to identify the specific development stage (s) where young people acquire the adult levels of maximal intensity exercise performance. Longitudinal studies, encompassing the entire maturity range (i.e. Tanner stages one to five) of young people are needed to clarify the evolution and stability of maximal intensity exercise performance with age and maturation. Multiple bouts of maximal intensity exercise can shed light on the fatigue and power recovery profile of young people and research in this area is deserving of encouragement.

Research 15

Michael Chia

Full Paper accepted for publication in Journal of PE & Recreation (HK) 

Explanations for children’s maximal intensity exercise fitness in the literature fluctuate between the incapacity of young children to generate energy anaerobically and a reduced need for the metabolic pathway. A number of propositions are advanced to explain young children’s relative inaptitude in anaerobic performance in comparison with older children and adults. These range from a smaller quantity of active muscle mass to perform the anaerobic task, to the quality of the muscle which may not yet be energetically, chemically or neurogenically mature, in comparison to their older and more mature counterparts. No one single factor, whether quantitative or qualitative in nature, however, can account exclusively for the anaerobic fitness of young people.

The other persuasive argument advanced is that children are less reliant than adults on the anaerobic energy pathway, for their energy supply. Arguments supporting such a contention include a swifter oxygen uptake response in children during high intensity exercise, a greater blood flow to muscle and greater oxygen extraction capability, and a blunted response to catecholamines during high intensity exercise. Either way, the evidence in the current literature is equivocal. Future research employing the use of non-invasive methods such as MRI to determine muscle fibre type, MRS to determine baseline energy substrates and utilisation rates during exercise, as well as mass spectroscopy to analyse oxygen uptake kinetics and other ventilatory responses during high intensity exercise, may help bring to the fore new knowledge to a most interesting area of research in children’s exercise. 

Research 16

Chia, YHM, Lee KS & Teo-Koh, SM

Full paper in biology of Sport,19:51-62, 2002

The purpose of the study was to examine if the Wingate Anaerobic Test (WAnT) is an acceptable all-out intensity exercise test for boys with moderate intellectual disability. Sixteen adolescent boys (aged 15.5±1.0yr) with moderate ID (IQ range 30-50) and with appropriate informed consent performed a 30-second WAnT on cycle ergometer on two separate days. Results of intra-class reliability were 0.93 and 0.95 (both p<0.05), for peak power (PP) and mean power (MP), respectively. The 95% limits of agreement for PP were –51W to –5W and –23W to 16W for MP. The co-efficient of variation for PP was 55% and 42% for MP. The results indicated that even though adolescent boys with moderate ID had apparently lower PP and MP values compared to their peers without ID, and demonstrated greater variability in the WAnT, given appropriate habituation and practice prior to testing, adolescent males with moderate ID were able to perform the WAnT with significant levels (P<0.05) agreement and reliability. 

Research 17

Michael Chia & John Wang

Full Paper accepted for publication in Journal of PE & Recreation (HK) 

The physical health benefits of regular exercise or a physically active lifestyle-better blood profile, protection against heart disease, stroke, type II diabetes and certain forms of cancer-are widely acknowledged and accepted. Less understood is the role that regular physical activity and exercise play in the health of mind in young people. The balance of recent evidence suggests that regular physical activity and exercise contribute positively to a healthy mind. The physical health benefits of regular exercise or a physically active lifestyle-better blood profile, protection against heart disease, stroke, type II diabetes and certain forms of cancer-are widely acknowledged and accepted. Less understood is the role that regular physical activity and exercise play in the health of mind in young people. The balance of recent evidence suggests that regular physical activity and exercise contribute positively to a healthy mind. 

Research 18

Michael Chia

Full Paper accepted for publication in Journal of PE & Recreation (HK)

 There are physical and physiological differences between how young people cope with exercise in hot and cold environments. Young people are especially disadvantaged when their thermoregulatory capabilities are compared to those of adults. Physically, young people have greater surface-area-to-mass ratio, have lower blood volume per unit of body surface area and smaller sweat glands compared to adults. Physiologically, young people are less energy efficient when it comes to locomotion, they have lower maximal cardiac output and also lower sweat gland sensitivity when compared to adults. These differences mean that young people have to tolerate a greater thermal load when they exercise in the heat or that they lose heat faster when they exercise in a cold environment compared to adults. Physical education teachers, sports trainers and activity organisers must be informed of these facts and take the appropriate actions to ensure that young people are sufficiently shielded from harsh environmental conditions when they are engaged in physical activity. 

Research 19

Chia, YHM, Lee, KS & Teo-Koh SM

Full paper accepted for publication in Advances in Exercise & Sport Physiology

 The purpose of the study was to investigate to compare the Wingate Anaerobic Test (WAnT) performances of boys with and without intellectual disability. Sixteen boys with ID and 18 boys without ID with appropriate consent participated in the study. All participants in the study performed a WAnT on two separate test occasions. The results indicate that boys with ID have comparable levels of reliability and agreement in the WAnT as boys without ID but their performances are significantly more variable. The boys with ID were markedly less powerful and had lower post-exercise blood lactate than boys without ID.

Research 20

Michael Chia

Full Paper accepted for publication in Journal of PE & Recreation (HK) 

The study investigated the muscle power of the lower limbs in a group of 13 to 14 year old boys and girls. Participants were 48 boys (stature: 1.69±0.05m; body mass: 57.9±11.8kg; lower limb muscle mass: 16.4±2.5kg) and 38 girls (stature: 1.59±0.06m; body mass: 57.7±7.6kg; lower limb muscle mass: 12.5±1.2kg). Lower limb muscle mass (LLMM) was determined using a dual energy X-ray absorptiometric (DEXA) procedure. Participants completed a 30s Wingate Anaerobic Test (WAnT) where peak power (PP) and mean power (MP) were expressed in relation to LLMM using simple ratio standards and log-linear adjustment procedures. Boys and girls had similar ratio-scaled PP (37.7±4.2W vs. 37.6±2.3W; P>0.05), MP (28.0±8.4W vs. 33.7±13W), and log-linear adjusted PP (495W vs. 488W, p>0.05) and MP (423W vs. 422W, p>0.05) when they were expressed 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 ratio-scaling or allometric modeling, allometric modeling of sample-specific exercise data is recommended to produce an appropriate size-independent variable, to allow comparisons in performance between two distinct groups of participants.

Research 21

Michael Chia & Quek Jin Jong

Full paper in saudi journal of disability & rehabilitation, 6: 283-289, 2001I

In many developed and developing countries, asthma is thought to be the most common chronic illness in childhood and it appears to be increasing in prevalence. Bronchial hyper-responsiveness (breathlessness, fatigue, chest pain, etc) to various stimuli, including exercise is the most specific sign of asthma. Typically exercise-induced asthma (EIA) consists of coughing, wheezing, chest tightness, chest pain or any combination of these symptoms during exercise, or more so characteristically, about eight to 15 minutes after exercise. The symptoms of EIA are usually resolved between 30 and 90 minutes. A proper warm-up before strenuous physical activity, and importantly a warm-down following exercise appears to offer some protection from EIA. Prevention is the main objective in managing EIA. Some of these precautions can include: (i) an appropriate warm up before vigorous exercise and an a gradual warm down after the exercise; (ii) covering the nose and mouth with a mask or a scarf whilst exercising in cool environments; (iii) exercising only in warm and humidified environments and (iv) improving the baseline fitness of young people with asthma. The physical fitness and exercise performance of young people with asthma appears to be inferior to those of young people without asthma, but this could be due to their diminished levels of physical activity and avoidance of exercise. Young people with asthma can benefit from exercise programmes that help raise their levels of physical fitness, especially aerobic fitness. With the proper use of prescribed medication and effective asthma management, young people with asthma are capable of high levels of performance.

Research 22

Michael Chia, Serena Tan, Abbie Tan, Tan Soot Mei & Bervyn Lee

Full Paper accepted for publication in Journal of PE & Recreation (HK)

 The issue of heavy school bags is a common concern among educationists, parents and school children. The pervasiveness of the carriage of heavy school bags among 482 primary school pupils from two schools was studied. Pupils with parental consent participated in the study. No direct mention was made about the weighing of school bags. Pupils were grouped according to sex and primary levels (i.e. P1 & P2, aged 7-8 years and P3 & P4, aged 9-10 years). Two trained physical education teachers measured the body mass of the pupils with and without their school bags on a single weekday using the same calibrated weighing machine. Pupils also completed a 10-item questionnaire that solicited responses about the type of school bag carried, the number of bags carried, how the bags were carried, whether they felt that their bags were too heavy, if they had suffered pain, soreness or numbness from carrying the school bags and information about their travel to and from school. Primary 1 and 2 pupils carried bags that weighed between 16% and 17% of body mass (3.9±0.9kg for boys and 3.8±1.0kg for girls). Primary 3 and 4 pupils carried bags that weighed between 15% and 17% of body mass (5.1±1.4 kg for boys and 4.6±1.3kg for girls). 85% of the pupils surveyed used a backpack-type bag with two shoulder straps and 82.1% carried bags wearing the straps on two shoulders. 63.5% of the pupils reported that the bags that they carried were too heavy and 58% reported suffering from pain, soreness or numbness in the neck, shoulders or back from carrying their school bags. 79% of the boys from Primary 1 and 2, and Primary 3 and 4, exceeded the recommendation for the weight bag carried to be of no more than 15% of body mass. Percentages for girls were 72 for the Primary 1 and 2 grouping and 56 for the Primary 3 and 4 grouping. The figure increased to above 90% when the reference value of 10% of body mass was used as the recommended safe guideline for younger children. 60.4% of the lower primary group exceeded the 3.5 kg Ministry of Education (Singapore) guideline for school bags and 55.8% of the middle primary group exceeded the 4.5 kg guideline for carriage for school bags. Heavy school bags carried by primary school pupils in Singapore should be a cause for concern. More can be done to reduce the physical load of school bags for lower primary pupils by working in cooperation with parents to help pupils plan and pack the bags with only the essential materials required for schoolwork, encouraging and helping pupils to complete their written work during curriculum time, designating cupboard space for pupils to keep their non-core subject textbooks, innovative time-tabling to help reduce the book load that pupils have to carry, having an additional set of textbooks for all pupils in class, making available worksheets on-line to reduce the need for multiple workbooks and exercise books, and increased vigilance among teachers to spot and counsel the child at risk of excessive overloading of the school bag.. Two promising developments that can help ameliorate the need for textbooks are the use of an electronic textbook system called the EduPADÔ; another is the creation of an electronic learning environment within the school compound where pupils can access textbook and workbook information. Both educational initiatives are being pilot-tested in a number of schools in Singapore.

Research 23

Young people are computer savvy, physically inactive and unfit?

The associations among and computer use, physical activity and physical fitness among children and adolescents

Michael Chia, John Wang, Teo-Koh Sock Miang, Quek Jin Jong & Kiran Kumar

Full paper is in review in european journal of pe

 The study examined the associations among the number of hours of computer use, levels of physical activity and the physical fitness of young people. 120 primary school participants (mean age: 10.6 yrs) and 120 secondary school participants (mean age: 18.8 yrs), with the appropriate consents participated in the study. Data on computer use and its accessibility and self-reported levels of current physical activity were gleaned from questionnaire responses. Heart rate data using a telemetric system was collected over a mean of 10 hours over two weekdays and a weekend day from 30 boys and 30 girls. Physical fitness data of the participants were also collected. Results showed that computer use and its accessibility were higher than those reported for some developed countries and that the number of hours spent per week using the computer increased with age (6.0±5.0 vs. 8.6±7.7 hrs, p<0.05). No meaningful associations were detected among weekly number of hours of computer use; self reported levels of current physical activity, and physical fitness test awards. A small but significant correlation between hours of computer use and self-reported physical activity levels (r=0.23, p<0.05) in primary school participants was detected. Heart rate data revealed that most participants were physically in active (more than 90% had heart rate below 120 bpm) for most of the day, especially on the weekend day. Accumulated physical activity that comprised heart rate intensities described as light, moderate and vigorous increased with age for the weekday (116 vs. 34 min, p<0.05) and the weekend day (67 vs.11 min, p<0.05). Data showed that physical activity levels of children and adolescents did not fully meet the recommendations for appropriate quality and quantity of physical activity enunciated by the consensus statements of two international panels of experts in young people’s health.  

Research 24

Michael Chia & john Wang

Full paper in review in pediatric exercise science

 The present study examined the relationships among weight-for-height classifications, body weight satisfaction, perceived physical self-worth and physical fitness in girls and boys in a primary school. 518 pupils (275 boys and 243 girls) aged between nine and 13 years old participated in the study. Pupils were categorized as healthy weight, underweight or overweight based on the criteria outlined by the School Health Services of the Ministry of Health in Singapore. A questionnaire with items on body weight satisfaction and perceived physical self-worth was used to garner the responses of the pupils. The results of the study revealed that more than two and half times the number of pupils was classified as underweight compared to those who were classified as overweight based on their weight-for-height ratios. Across the three weight-for-height classifications, more pupils voiced their intention of wanting to lose body weight than to gain body weight. Underweight pupils were the most satisfied with their body weight, were the most physically fit and had the highest rating for perceived physical self-worth than the healthy weight and overweight groupings. Contrary to popular belief, girls and boys did not rate themselves differently in terms of perceived physical self-worth, but the younger pupils in primary four had higher perceived physical self-worth scores than the older pupils in primary six despite the latter scoring better for physical fitness than the former. Health promotion efforts in educating pupils about appropriate weight management in the primary schools should target not just pupils in the overweight group but also pupils who are in the healthy weight and underweight groupings. More should be done to ameliorate the insidious obsession to lose body weight for cosmetic reasons rather than for health reasons. Future research should investigate the reasons and motivations for young people’s weight management intentions. Such research should take into consideration both physical and psycho-socio-cultural determinants and consequences of young peoples’ weight management decisions.

Research 25

Velocity composite isokinetic torque of male and female adults

Quek Jin Jong & Michael Chia
(Full paper submitted to Asian Journal of Exercise & Sport Sciences in 2004)

The purpose of the study was to examine velocity-specific composite isokinetic leg extension and flexion torque of adult participants, using allometric modeling. Seventeen men (25.0y, 1.73m & 63.6kg) and 15 women (22.5y, 1.60m & 51.1kg) participated in the study. Peak concentric isokinetic leg extension and flexion torque at 1.05, 3.14 and 5.20 rad/s were determined using a Cybex 6000 isokinetic dynamometer. Composite concentric isokinetic torque (CCIT) (i.e. sum of peak extension and flexion torque) generated at 1.05 rad/s was 1.87-1.69 times that at 5.20 rad/s for men and women, respectively. CCIT in Nm in women were 59-65% that of men but were increased to 73-81% and 71-81% that of men when the data were ratio-scaled to body mass (BM) and allometrically scaled to BMb=0.79, 1.19 & 1.05, respectively. Common identified b exponents for men and women between CCIT and BM included b=1.0 for torque as predicted by geometric similarity theory, but sample specific derived b exponents are recommended in order to accurately compute body size-free power function ratios.

Research 26

Measured maximal oxygen uptake in a multi-stage shuttle test and treadmill-run test in trained athletes

Michael Chia, Rahid Aziz & Teh Kong Chuan 
(Full paper submitted to Journal of Sports Medicine & Physical Fitness in 2004)

Objective: The aims of the study were: i) to establish the reliability of measured maximal oxygen uptake (MV02_max) during a multi-stage shuttle test (MST) and ii) to compare the MV02_max during the MST with the MV02_max for an incremental treadmill-run test (TRT) in trained athletes. Experimental design: This is a cross-sectional, descriptive study.  Setting. The study was conducted at the Sports Medicine and Research Centre, Singapore Sports Council. Participants. Eight well trained endurance-athletes (END) and eight athletes involved in team games (GAM). Measures: Subjects performed the MST twice (i.e. MST1 & MST2) and the TRT once, in three separate sessions. MV02_max attained in the MST and TRT was measured using a portable respiratory analyser (K4 RQ Cosmed). Results: Reliability measures of typical error (TE), coefficient of variation (CV) and test-retest intra-class correlation (ICC), for MV02_max in the MST, in L·min^-1 and ml·kg·^-1min^-1, were 0.14 and 2.19; 3.5 and 3.6; and 0.90 and 0.91, respectively. Measured V02_max (mean±SD) in MST1 and MST2 were not significantly different for END athletes (4.18±0.39 vs. 4.10±0.28 L·min^-1, P>0.05) and GAM athletes (4.01±055 vs. 4.01±0.51 L·min^-1, P>0.05). MV02_max attained in the MST and TRT were significantly different for the END athletes (4.10±0.28 vs. 4.45±0.31 L·min^-1, P<0.05) but were similar for GAM athletes (4.01±0.51 vs. 4.10±0.59 L·min^-1 P>0.05). Conclusions: Measured V02_max in the MST was reliable and showed acceptable levels of agreement. MV02_max in the MST was lower than that measured in the TRT for the END athletes but not for the GAM athletes. Sport-specificity is an important consideration, especially when testing END athletes for V02_max.

Research 27

Reliability of stair-climb test for cardiovascular fitness

Frankie Tan, Rashid Aziz, Teh Kong Chuan & Michael Chia
(Full paper submitted to Advances in Exercise & Sport Physiology in 2004) 

 The purpose of this study was to evaluate the reliability of the Stair-Climb Test (SCT) of Cardiorespiratory Fitness in healthy male and female Singaporean adults. Thirty men (mean age 37 ± 9 years) and 22 women (mean age 35 ± 11 years) underwent two SCTs (SCT 1 & SCT 2) at a public Housing and Development Board (HDB) staircase, with at least 24 hours separating each test session. Reliability of the SCT was assessed using intraclass correlation coefficient (ICC), coefficient of variation (CV) and change in the mean. The test-retest ICCs for predicted maximal oxygen uptake (PVO_2max) of men and women were 0.95; CV of men and women for PVO_2max, were 2.1% and 1.6% respectively; and change in the mean of men and women for PVO_2max, were 1.2% and 1.6% respectively. Heart rate at the end of climb (HR_end) and climb time (CT) were highly reproducible, with ICCs over 0.80, CVs below 6% and changes in the means of not more than 5%. The results indicated that the SCT was a very reliable field test and could serve as an effective tool for cardiorespiratory fitness assessment. Further research should evaluate the sensitivity of the SCT to monitor changes in VO_2max following exercise training.

Research 28

Practising appropriate ethics in research involving young people

Quek Jin Jong, Michael Chia & John Wang
(Full paper submitted to Journal of Physical Education & Recreation in 2004)

 This commentary paper addresses the principal issues in practicing appropriate ethics in research in exercise and sport science. Ethical considerations include the suitability of the research question, appropriate research design and statistical analysis and the presentation and publication of the research findings. Special mention is given to research involving young people and the need to be aware of cultural and religious sensitivities.

本 文 簡 要 探 討 運 動 和 體 育 科學 研 究 的 道 德 規 範。 所 討 論 的 五 大 標 題包 括 研 究 目 標 和 假 設 ，研 究 方 法 ， 統 計 過 程 ， 研 究 報 告  與 論 文 發 表 。 其 重 點 是 著 重 在 以 青 少 年 為 研 究 對 象 的 研 究 。

Research 29

Composite Concentric isokinetic torque and wingate anaerobic test power of male and female adults in relation to lower limb muscle mass as determined using dual energy x-ray absorptiometry

Michael Chia, Quek Jin Jong & Omri Inbar
(Full paper submitted to Medicine & Science in Sports & Exercise in 2004)

  The purpose of the study was to examine the relationships between composite concentric isokinetic torque (CCIT) of the lower limbs, peak power (PP) and mean power (MP), of male and female adults using allometric scaling. 16 males (age: 24.6yrs, stature: 1.71m & body mass: 64.5kg) and 18 females (age: 20.4y, stature: 1.62m & body mass: 52.1kg) participated in the study. Lower limb muscle mass (LLMM) of the participants was determined using dual energy X-ray absorptiometry (QRR 4500 Elite Hologic). Peak leg extension and flexion torque at 1.02, 3.12 and 5.20 rad/s were determined using an isokinetic dynamometer (Cybex 6000), and were added to derive CCIT. PP and MP were derived from a 30-second Wingate Anaerobic Test (WAnT), using cycle ergometry (Monark 814E). Men had smaller body mass index (19.8±2.7 vs.22.0±2.3 kg/m² p<0.05) and greater LLMM (20.1±3.3 vs. 12.4±1.7 kg, p<0.05) than women. CCIT in men was significantly greater than women at 1.05 rad/s (320±54 vs. 191±32 Nm, p <0.05), at 3.12 rad/s (230±45 vs. 131±30 Nm, p<0.05) and at 5.20 rad/s (177±33 vs. 110±23 Nm, p<0.05). PP in watts was significantly greater in men than in women (671±72 vs. 468±85 W, p<0.05), as was MP (557±59 vs. 372±52 W, p<0.05). PP expressed in W/kg LLMM was significantly greater in women than in men (37.7±3.3 vs. 33.7±4.2, p<0.05) as was for MP (30.2±2.8 vs.  27.9±3.5, p<0.05). When the same data were allometrically adjusted to LLMM, PP expressed in W/kg LlMM^0.72 (77.6±7.4 vs. 72.9±8.4, p>0.05) and MP expressed in W/kg LLMM^0.76 (57.2±5.7 vs. 55.1±4.8, p>0.05) were the same in men and women. There was also no sex difference in CCIT at 1.05 rad/s (19.7±3.0 vs. 18.4±2.1 Nm/kg LLMM^0.93, p>0.05), at 3.12 rad/s (6.7±1.3 vs. 6.7±1.1 Nm/kg LLMM^1.18, p>0.05) and at 5.20 rad/s (6.2±1.2 vs. 6.6±1.0 Nm/kg LLMM^1.12, p>0.05). Significant correlations established between PP (W/kg LLMM^0.72) and MP (W/kg LLMM^0.76) with CCIT at 1.05 rad/s (Nm/kg LLMM^0.93), at 3.12 rad/s (Nm/kg LLMM^1.18) and at 5.20 rad/s (Nm/kg LLMM^1.12) ranged from r= 0.54 to 0.66 (all, p<0.05) for men, and r=0.54 to 0.84 for women (all, p<0.05). Results showed no sex difference in CCIT, PP and MP in men and women when the data were allometrically scaled in relation to LLMM. Body size-free measures for PP and MP showed higher correlations with body size-free measures for CCIT at 5.20 rad/s than at 1.05 rad/s, even though CCIT at 1.05 rad/s was significantly greater than CCIT at 5.20 rad/s in males and in females.

Research 30

Relationship between angiotensin-converting enzyme ID polymorphism and VO2max of Chinese males

 (Full paper in Life Sciences)
Bin Zhaoa, Shabbir M. Moochhalaa,*, Su-yin Thama, Jia Lua, Michael Chiab, Christopher Byrnea, Qichen Hub, Lionel K.H. Leea 

Several studies have shown that the angiotensin-converting enzyme (ACE) I allele is associated with enhanced physical performance. We investigated whether this phenomenon is observed in a cohort of 67 Chinese men in Singapore. Angiotensin-converting enzyme ID polymorphism was typed with PCR method and maximal oxygen uptake (VO2max) of the DD, ID, and II genotypes was compared. Analysis of covariance revealed that VO2max was significantly higher ( p < 0.05) for the DD genotype (57.86 F 3.5 ml.kg._ 1min_ 1) versus the ID (50.58 F 1.80ml.kg._ 1min_ 1) or II (50.48 F 1.58 ml.kg._ 1 min_ 1) genotype. Our findings suggest that the ACE DD genotype in young adult Chinese males is associated with higher levels of VO2max.