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Biomedical subjects

Yong-Hao Pua

Publications and source records attributed to Yong-Hao Pua.

6 recordsLinked to original sources
PubMed2006

Categorization of low cardiorespiratory fitness using obesity indices in non-smoking Singaporean women.

OBJECTIVE: To revisit cut-off values of BMI, waist circumference (WC), and waist-to-stature ratio (WSR) based on their association with cardiorespiratory fitness (CRF). The derived cut-off points were compared with current values (BMI, 25.0 kg/m(2); WC, 80 cm) as recommended by the World Health Organization. RESEARCH METHODS AND PROCEDURES: Anthropometric indices were measured in a cross sectional study of 358 Singaporean female employees of a large tertiary hospital (63% Singaporean Chinese, 28% Malays, and 9% Indians). CRF was determined by the 1-mile walk test. Receiver operating characteristic curves were constructed to determine cut-off points. RESULTS: The cut-off points for BMI, WC, and WSR were 23.6 kg/m(2), 75.3 cm, and 0.48, respectively. The areas under the curve of BMI, WC, and WSR were 0.68, 0.74, and 0.74, respectively. For a given BMI, women with low CRF had higher WSR compared with women with high CRF. DISCUSSION: These findings provide convergent evidence that the cut-off points for Singaporean women were lower than the World Health Organization's criteria but were in good agreement with those reported for Asians.

Adult↗
PubMed2006

Effects of allometric scaling and isokinetic testing methods on the relationship between countermovement jump and quadriceps torque and power.

Determination of the strongest possible relationship between isokinetic quadriceps and functional performance measurements in healthy females would allow sports medicine practitioners to establish normative values when examining muscular performance in injured females. Previous attempts to correlate both measurements have, however, produced inconsistent results. The purpose of this study was to examine the effects of allometric scaling, isokinetic testing velocities, reciprocal and non-reciprocal isokinetic testing on the relationship between countermovement jump (CMJ) and isokinetic quadriceps torque and power in recreational females athletes. Seventeen females (age 21.0 +/- 2.0 years, body mass index 19.5 +/- 1.0 kg x m(-2)) performed isokinetic quadriceps and CMJ tests. Isokinetic peak torque and average power were obtained reciprocally and non-reciprocally at 1.05 and 3.14 rad x s(-1), and were corrected for body mass by allometric modelling. Pearson product-moment correlation (r) was used to assess the relationship between the isokinetic parameters and the CMJ measurements. Coefficients of determination (r(2)) were calculated to determine the magnitude of common variance. The r-values for all non-allometrically modelled non-reciprocal parameters were greater (r = 0.58-0.63) than isokinetic parameters obtained reciprocally (r = 0.28-0.47). Using allometric scaling, non-reciprocal isokinetic data accounted for an additional 2-9% of the CMJ height variance, and statistically significant correlations were obtained at both 1.05 and 3.14 rad x s(-1). Allometrically scaled, non-reciprocal isokinetic peak torque and average power at 1.05 rad x s(-1) had the highest correlation with CMJ (r(2) = 0.49). At both 1.05 and 3.14 rad x s(-1), non-reciprocal quadriceps parameters correlated more closely with CMJ measurements than do reciprocal contractions. Normalization for body size by allometrically scaling may further improve correlations with CMJ performance.

Adult↗
PubMed2006

Allometric analysis of physical performance measures in older adults.

BACKGROUND AND PURPOSE: Body mass is a confounding variable in human performance, and adjusting physical performance measures for body mass differences would allow meaningful individual and group comparisons. The purpose of this study was to allometrically determine the relationship between body mass and handgrip and ankle dorsiflexor performance on the Timed "Up & Go" Test (TUGT). SUBJECTS: One hundred thirty-one subjects (33 male and 98 female) participated. METHODS: All physical performance measures were adjusted for the influence of body mass, sex, and age using an allometric scaling procedure. RESULTS: For handgrip force, the body mass exponent from allometric analysis was 0.63. For the TUGT, the body mass exponent was 0.073. For ankle dorsiflexor force and torque, the body mass exponents were 0.82 and 0.91, respectively. DISCUSSION AND CONCLUSION: The body mass exponents for handgrip force and the TUGT agree with previous clinical data and theoretical expectations. Studies investigating normalized handgrip force in older adults should consider an allometric scaling approach.

Aged↗
PubMed2005

Anthropometric indices as screening tools for cardiovascular risk factors in Singaporean women.

Previous studies have suggested the need to revise the World Health Organization (WHO) cut-off values for the various indices of obesity and fat distribution in Singapore. The purpose of this study was to delineate cut-off points of body mass index (BMI), waist-hip ratio (WHR), waist circumference (WC), and waist-stature ratio (WSR) as screening tools for cardiovascular risk factors in Singaporean women. Anthropometric indices were measured in a cross sectional survey of 566 subjects (60% Chinese individuals, 28% Malay individuals and 12% Indian individuals). Cardiovascular risk factors were determined by measuring blood pressure, serum lipids, and fasting blood glucose levels. Receiver Operating Characteristic (ROC) curves were constructed to determine cut-off points. Forward logistic regression and area under curves (AUC) were used to determine the best anthropometric index. For at least one cardiovascular risk factor (hypertension, dyslipidaemia and diabetes mellitus), the cut-off points for BMI, WHR, WC and WSR were around 23.6 kg/m(2), 0.80, 77.8 cm and 0.48 for Singaporean females. The AUC of WSR was the highest for all three risk factors in females (0.79 for hypertension, 0.70 for dyslipidaemia, 0.88 for diabetes mellitus). Regression analyses revealed that WSR was independently associated with all risk factors. For Singaporean female adults, the cut-off points were lower than the criteria suggested by the WHO, but were in agreement with those reported for Asians. BMI, WHR, WC and WSR may be used as screening tools for cardiovascular risk factors, of which WSR may be the best anthropometric index.

Adolescent↗