Displaying publications 1 - 20 of 25 in total

  1. Abutalib M, Batle J, Ooi CH
    Chaos, 2016 Jul;26(7):073113.
    PMID: 27475073 DOI: 10.1063/1.4959138
    The total electrostatic energy of systems of identical particles of equal charge is studied in configurations bounded in space, but divergent in the number of charges. This approach shall guide us to unveil a non-linear, functional form specifying the divergent nature of system energy. We consider fractals to be physical entities, with charges located in their vertices or nodes. This description is interesting since features, such as the corresponding fractal dimension, can characterize the total energy EN. Finally, at local length scales, we describe how energy diverges at charge accumulation points in the fractal, that is, almost everywhere by definition.
  2. Ooi CH, Talib MR
    Sci Rep, 2016 08 30;6:32056.
    PMID: 27571644 DOI: 10.1038/srep32056
    We report on some interesting phenomena in the focusing and scattering of femtosecond laser pulses in free space that provide insights on intense laser plasma interactions. The scattered image in the far field is analyzed and the connection with the observed structure of the plasma at the focus is discussed. We explain the physical mechanisms behind the changes in the colorful and intricate image formed by scattering from the plasma for different compressions, as well as orientations of plano-convex lens. The laser power does not show significant effect on the images. The pulse repetition rate above 500 Hz can affect the image through slow dynamics The spectrum of each color in the image shows oscillatory peaks due to interference of delayed pulse that correlate with the plasma length. Spectral lines of atomic species are identified and new peaks are observed through the white light emitted by the plasma spot. We find that an Ar gas jet can brighten the white light of the plasma spot and produce high resolution spectral peaks. The intricate image is found to be extremely sensitive and this is useful for applications in sensing microscale objects.
  3. Nguyen DM, Soci C, Ooi CH
    Sci Rep, 2016;6:21083.
    PMID: 26879520 DOI: 10.1038/srep21083
    Phaseonium is a three-level Λ quantum system, in which a coherent microwave and an optical control (pump) beams can be used to actively modulate the dielectric response. Here we propose a new metamaterial structure comprising of a periodic array of triangular phaseonium metamolecules arranged as a trefoil. We present a computational study of the spatial distribution of magnetic and electric fields of the probe light and the corresponding transmission and reflection, for various parameters of the optical and microwave beams. For specific values of the probing frequencies and control fields, the phaseonium can display either metallic or dielectric optical response. We find that, in the metallic regime, the phaseonium metamaterial structure supports extremely large transmission, with optical amplification at large enough intensity of the microwave thanks to strong surface plasmon coupling; while, in the dielectric regime without microwave excitation, the transmission bandwidth can be tuned by varying the control beam intensity. Implementation of such phaseonium metamaterial structure in solid-state systems, such as patterned crystals doped with rare-earth elements or dielectric matrices embedded with quantum dots, could enable a new class of actively tunable quantum metamaterials.
  4. Lai MY, Ooi CH, Lau YL
    Am. J. Trop. Med. Hyg., 2018 03;98(3):700-703.
    PMID: 29260656 DOI: 10.4269/ajtmh.17-0738
    The aim of this study was to develop a recombinase polymerase amplification (RPA) combined with a lateral flow (LF) strip method for specific diagnosis of Plasmodium knowlesi. With incubation at 37°C, the 18S rRNA gene of P. knowlesi was successfully amplified within 12 minutes. By adding a specifically designed probe to the reaction solution, the amplified RPA product can be visualized on a LF strip. The RPA assay exhibited high sensitivity with limits of detection down to 10 parasites/μL of P. knowlesi. Nonetheless, it was demonstrated that all P. knowlesi (N = 41) and other Plasmodium sp. (N = 25) were positive while negative samples (N = 8) were negative. Therefore, a combination of RPA and LF strip detection is a highly promising approach with the potential to be suitable for use in resource-limited settings.
  5. Ooi CH, Ng SK, Omar EA
    Appl Physiol Nutr Metab, 2020 May;45(5):513-519.
    PMID: 31675478 DOI: 10.1139/apnm-2019-0553
    There is emerging evidence that hydrogen-rich water (H2-water) has beneficial effects on the physiological responses to exercise. However, few studies investigate its ergogenic potential. This randomized controlled trial examined the effects of H2-water ingestion on physiological responses and exercise performance during incremental treadmill running. In a double-blind crossover design, 14 endurance-trained male runners (age, 34 ± 4 years; body mass, 63.1 ± 7.2 kg; height, 1.72 ± 0.05 m) were randomly assigned to ingest 2 doses of 290-mL H2-water or placebo on each occasion. The first bolus was given before six 4-min submaximal running bouts, and the second bolus was consumed before the maximal incremental running test. Expired gas, heart rate (HR), and ratings of perceived exertion (RPE) were recorded; blood samples were collected at the end of each submaximal stage and post maximal running test. Cardiorespiratory responses, RPE, and blood gas indices were not significantly different at each submaximal running intensity (range: 34%-91% maximal oxygen uptake) between H2-water and placebo trials. No statistical difference was observed in running time to exhaustion (618 ± 126 vs. 619 ± 113 s), maximal oxygen uptake (56.9 ± 4.4 vs. 57.1 ± 4.7 mL·kg-1·min-1), maximal HR (184 ± 7 vs. 184 ± 7 beat·min-1), and RPE (19 ± 1 vs. 19 ± 1) in the runners between the trials. The results suggest that the ingestion of 290 mL of H2-water before submaximal treadmill running and an additional dose before the subsequent incremental running to exhaustion were not sufficiently ergogenic in endurance-trained athletes. Novelty Acute ingestion of H2-water does not seem to be ergogenic for endurance performance. A small dose of H2-water does not modulate buffering capacity during intense endurance exercise in athletes.
  6. Lai MY, Ooi CH, Lau YL
    Am. J. Trop. Med. Hyg., 2017 Nov;97(5):1597-1599.
    PMID: 28820700 DOI: 10.4269/ajtmh.17-0427
    In this study, we developed a recombinase polymerase amplification (RPA) assay for specific diagnosis of Plasmodium knowlesi. Genomic DNA was extracted from whole blood samples using a commercial kit. With incubation at 37°C, the samples were successfully amplified within 20 minutes. The end product of RPA was further examined by loading onto agarose gel and a specific band was observed with a size of 128 bp. The RPA assay exhibited high sensitivity with limits of detection down to one copy of the plasmid. From the specificity experiments, it was demonstrated that all P. knowlesi samples (N = 45) were positive while other Plasmodium spp. (N = 42) and negative samples (N = 6) were negative. Therefore, the RPA assay is a highly promising approach with the potential to be used in resource-limited settings. This assay can be further optimized for bedside and on field application.
  7. Rouhi J, Mahmud S, Naderi N, Ooi ChR, Mahmood MR
    Nanoscale Res Lett, 2013;8(1):364.
    PMID: 23981366 DOI: 10.1186/1556-276X-8-364
    Well-dispersed fish gelatin-based nanocomposites were prepared by adding ZnO nanorods (NRs) as fillers to aqueous gelatin. The effects of ZnO NR fillers on the mechanical, optical, and electrical properties of fish gelatin bio-nanocomposite films were investigated. Results showed an increase in Young's modulus and tensile strength of 42% and 25% for nanocomposites incorporated with 5% ZnO NRs, respectively, compared with unfilled gelatin-based films. UV transmission decreased to zero with the addition of a small amount of ZnO NRs in the biopolymer matrix. X-ray diffraction showed an increase in the intensity of the crystal facets of (10ī1) and (0002) with the addition of ZnO NRs in the biocomposite matrix. The surface topography of the fish gelatin films indicated an increase in surface roughness with increasing ZnO NR concentrations. The conductivity of the films also significantly increased with the addition of ZnO NRs. These results indicated that bio-nanocomposites based on ZnO NRs had great potentials for applications in packaging technology, food preservation, and UV-shielding systems.
  8. Nadarajan VS, Ooi CH, Sthaneshwar P, Thompson MW
    Int J Lab Hematol, 2010 Feb;32(1 Pt 2):82-7.
    PMID: 19170774 DOI: 10.1111/j.1751-553X.2008.01132.x
    Altitude training is sometimes employed by elite endurance athletes to improve their sea level performance. This improvement results from the increased red cell mass consequent upon the boost in erythropoietin (EPO) level that occurs as a response to the relatively hypoxic environment at high altitudes. We measured serum EPO levels together with various red cell and reticulocyte parameters including immature reticulocyte fraction (IRF) in eight national track-endurance cyclists, resident at sea-level, prior to and upon return from an altitude of approximately 1905 m. Reticulocytes and soluble transferrin receptor (sTfR) were significantly increased with reduction in ferritin levels immediately on return from high altitude indicating increased erythropoietic activity. IRF in particular showed a significant peak immediately on return but decline to sub-baseline levels by day 9, and recovery to baseline by day 16. Our results indicate that IRF is a sensitive marker of erythropoietic status in athletes undergoing altitude training and subsequent loss of EPO stimuli on return to sea level.
  9. Liew JWK, Ooi CH, Snounou G, Lau YL
    Am. J. Trop. Med. Hyg., 2019 12;101(6):1402-1404.
    PMID: 31595863 DOI: 10.4269/ajtmh.19-0305
    Here are two cases of recurring ovale malaria in Sarawak, Malaysia, that are likely relapses that occurred 1-2 months after successful treatment of the initial imported falciparum malaria with artemisinin-based combined therapy. The patients have no history or recollection of previous malaria episodes. These cases add to the limited evidence on the relapsing nature of Plasmodium ovale, after a febrile episode. In regions where P. ovale is not known to be autochthonous, active follow-up of treated imported malaria patients is highly recommended following their return, particularly to areas nearing or having achieved elimination.
  10. Lai MY, Ooi CH, Jaimin JJ, Lau YL
    Am. J. Trop. Med. Hyg., 2020 06;102(6):1370-1372.
    PMID: 32228783 DOI: 10.4269/ajtmh.20-0001
    The incidence of zoonotic malaria, Plasmodium knowlesi, infection is increasing and now is the major cause of malaria in Malaysia. Here, we describe a WarmStart colorimetric loop-mediated isothermal amplification (LAMP) assay for the detection of Plasmodium spp. The detection limit for this assay was 10 copies/µL for P knowlesi and Plasmodium ovale and 1 copy/µL for Plasmodium falciparum, Plasmodium vivax, and Plasmodium malariae. To test clinical sensitivity and specificity, 100 microscopy-positive and 20 malaria-negative samples were used. The WarmStart colorimetric LAMP was 98% sensitive and 100% specific. Amplification products were visible for direct observation, thereby eliminating the need for post-amplification processing steps. Therefore, WarmStart colorimetric LAMP is suitable for use in resource-limited settings.
  11. Nahri DG, Mathkoor FH, Raymond Ooi CH
    J Phys Condens Matter, 2017 Feb 08;29(5):055701.
    PMID: 27966466 DOI: 10.1088/1361-648X/29/5/055701
    A dissipative quantum dot (QD)-cavity system, where the QD is initially prepared in the excited state with no photon in the cavity, coupled to a longitudinal acoustic (LA) phonon reservoir is studied using a numerically exact real-time path-integral approach. Three distinct dynamical regimes of weak (WC), strong (SC), and coherent coupling (CC) are discussed and more accurate conditions identifying them are presented. Our results show that to have the CC regime, which is characterized by clear vacuum Rabi oscillation (VRO), vacuum Rabi splitting (VRS) should be larger than the sum of the widths of the corresponding peaks. In order to distinguish between contributions of population decay and impure dephasing, induced by LA phonon bath and the dissipations, we propose a two-part phenomenological expression, corresponding to the population decay and impure dephasing, which fits the QD-cavity decay curves perfectly and is used to calculate the corresponding spectra. We demonstrate that the effective population decay rate (the emission rate) increases from the carrier recombination rate to a maximum value, which is the mean of the QD and cavity dissipation rates, with QD-cavity coupling strength. To study the role of the effective impure dephasing rate on the width of the central peak of the spectra we introduce a quantity that can also be applied in determining the distinct coupling regimes. This quantity enables us to identify the onset of the SC regime as the point where the impure dephasing term begins to contribute to the central band of the spectrum significantly, as a result of the existence of VRO with a very small frequency (unclear VRO) at the corresponding decay curve. Its contribution to the width of the central peak increases with the coupling strength up to the onset of the CC regime, then reduces as a result of the appearance of sidebands in the spectra, which originates from clear VRO. The effective population decay and impure dephasing rate contribute solely to the width-of the central and sideband peaks of the triplet spectra respectively-only beyond a very large coupling strength which is the same across the considered temperature range. For higher temperatures, the maximum achievable emission rate can be obtained at larger coupling strengths.
  12. Rouhi J, Mamat MH, Ooi CH, Mahmud S, Mahmood MR
    PLoS ONE, 2015;10(4):e0123433.
    PMID: 25875377 DOI: 10.1371/journal.pone.0123433
    High-density and well-aligned ZnO-ZnS core-shell nanocone arrays were synthesized on fluorine-doped tin oxide glass substrate using a facile and cost-effective two-step approach. In this synthetic process, the ZnO nanocones act as the template and provide Zn2+ ions for the ZnS shell formation. The photoluminescence spectrum indicates remarkably enhanced luminescence intensity and a small redshift in the UV region, which can be associated with the strain caused by the lattice mismatch between ZnO and ZnS. The obtained diffuse reflectance spectra show that the nanocone-based heterostructure reduces the light reflection in a broad spectral range and is much more effective than the bare ZnO nanocone and nanorod structures. Dye-sensitized solar cells based on the heterostructure ZnO-ZnS nanocones are assembled, and high conversion efficiency (η) of approximately 4.07% is obtained. The η improvement can be attributed primarily to the morphology effect of ZnO nanocones on light-trapping and effectively passivating the interface surface recombination sites of ZnO nanocones by coating with a ZnS shell layer.
  13. Ooi CH, Cheah WK, Sim YL, Pung SY, Yeoh FY
    J. Environ. Manage., 2017 Jul 15;197:199-205.
    PMID: 28384613 DOI: 10.1016/j.jenvman.2017.03.083
    Urea removal is an important process in household wastewater purification and hemodialysis treatment. The efficiency of the urea removal can be improved by utilizing activated carbon fiber (ACF) for effective urea adsorption. In this study, ACF was prepared from oil palm empty fruit bunch (EFB) fiber via physicochemical activation using sulfuric acid as an activating reagent. Based on the FESEM result, ACF obtained after the carbonization and activation processes demonstrated uniform macropores with thick channel wall. ACF was found better prepared in 1.5:1 acid-to-EFB fiber ratio; where the pore size of ACF was analyzed as 1.2 nm in diameter with a predominant micropore volume of 0.39 cm(3) g(-1) and a BET surface area of 869 m(2) g(-1). The reaction kinetics of urea adsorption by the ACF was found to follow a pseudo-second order kinetic model. The equilibrium amount of urea adsorbed on ACF decreased from 877.907 to 134.098 mg g(-1) as the acid-to-fiber ratio increased from 0.75 to 4. During the adsorption process, the hydroxyl (OH) groups on ACF surface were ionized and became electronegatively charged due to the weak alkalinity of urea solution, causing ionic repulsion towards partially anionic urea. The ionic repulsion force between the electronegatively charged ACF surface and urea molecules became stronger when more OH functional groups appeared on ACF prepared at higher acid impregnation ratio. The results implied that EFB fiber based ACF can be used as an efficient adsorbent for the urea removal process.
  14. Mallepaddi PC, Lai MY, Podha S, Ooi CH, Liew JW, Polavarapu R, et al.
    Am. J. Trop. Med. Hyg., 2018 09;99(3):704-708.
    PMID: 29943720 DOI: 10.4269/ajtmh.18-0177
    The present study aims to develop a method for rapid diagnosis of malaria using loop-mediated isothermal amplification (LAMP) combined with a lateral flow device (LFD). By adding the biotin-labeled and fluorescein amidite-labeled loop primers to the LAMP reaction solution, the end product can be visualized on a LFD. The entire procedure takes approximately 42 minutes to complete, LAMP assay exhibited high sensitivity, as the detection limit was 0.01 pg/μL for all five Plasmodium species. It was demonstrated that all Plasmodium knowlesi (N = 90) and Plasmodium vivax (N = 56) were positively amplified by LAMP-LFD assay, whereas healthy donor samples (N = 8) were negative. However, not all mixed infections were positive, and other infected nonmalaria samples were negative. Loop-mediated isothermal amplification-LFD represents a robust approach with potential suitability for use in resource-constrained laboratories. We believe that LAMP-LFD has a potential to be developed as point-of-care diagnostic tool in future.
  15. Ooi CH, Bujang MA, Tg Abu Bakar Sidik TMI, Ngui R, Lim YA
    Acta Trop., 2017 Dec;176:83-90.
    PMID: 28768148 DOI: 10.1016/j.actatropica.2017.07.027
    Malaria is still of great public health concern, especially in Malaysian Borneo. The aim of this study was to determine the trends of P. knowlesi infection in Sarawak, Malaysia and to forecast the incidence of P. knowlesi until the year 2040. Data on P. knowlesi malaria cases from 1992 to the year 2014 were obtained from the Sarawak Health Department, Malaysia. ARIMA model was applied to forecast the future incidence of P. knowlesi infection. The data for the whole of Sarawak and subsequently the selected six districts which have high incidence rates of P. knowlesi infection were analyzed. Results of the analysis showed that there was an increasing trend of P. knowlesi cases from the year 1992-2014 (p<0.001). The trend in the incidence started to increase in the year 2008 (p=0.029). The incidence rate per 100,000 populations was between 4.15 in the year 1992 and 42.03 in the year 2014. High incidence of P. knowlesi infections has been detected in the districts adjacent to each other within the interior region of Sarawak. The forecasted incidence and incidence rate per 100,000 populations in the year 2020 were 1229 and 44.04, respectively, while those in the year 2040 were 2056 and 62.91, respectively. The forecasted incidence showed an upward trend highlighting an urgent need to draw up strategic and holistic prevention plans to limit further the increase in P. knowlesi morbidity and mortality in Sarawak. It is imperative that these measures are customized taking into consideration the challenges faced in the interior areas of Sarawak and the behavior of the main vector of P. knowlesi (i.e., An. latens) in Sarawak.
  16. de Silva JR, Amir A, Lau YL, Ooi CH, Fong MY
    PLoS ONE, 2019;14(9):e0222681.
    PMID: 31536563 DOI: 10.1371/journal.pone.0222681
    The Duffy blood group plays a key role in Plasmodium knowlesi and Plasmodium vivax invasion into human erythrocytes. The geographical distribution of the Duffy alleles differs between regions with the FY*A allele having high frequencies in many Asian populations, the FY*B allele is found predominately in European populations and the FY*Bes allele found predominantly in African regions. A previous study in Peninsular Malaysia indicated high homogeneity of the dominant FY*A/FY*A genotype. However, the distribution of the Duffy genotypes in Malaysian Borneo is currently unknown. In the present study, the distribution of Duffy blood group genotypes and allelic frequencies among P. knowlesi infected patients as well as healthy individuals in Malaysian Borneo were determined. A total of 79 P. knowlesi patient blood samples and 76 healthy donor samples were genotyped using allele specific polymerase chain reaction (ASP-PCR). Subsequently a P. knowlesi invasion assay was carried out on FY*AB/ FY*A and FY*A/ FY*A Duffy genotype blood to investigate if either genotype conferred increased susceptibility to P. knowlesi invasion. Our results show almost equal distribution between the homozygous FY*A/FY*A and heterozygous FY*A/FY*B genotypes. This is in stark contrast to the Duffy distribution in Peninsular Malaysia and the surrounding Southeast Asian region which is dominantly FY*A/FY*A. The mean percent invasion of FY*A/FY*A and FY*A/FY*B blood was not significantly different indicating that neither blood group confers increased susceptibility to P. knowlesi invasion.
  17. Fong MY, Lau YL, Jelip J, Ooi CH, Cheong FW
    J. Genet., 2019 Sep;98.
    PMID: 31544794
    Plasmodium knowlesi contributes to the majority of human malaria incidences in Malaysia. Its uncontrollable passage among the natural monkey hosts can potentially lead to zoonotic outbreaks. The merozoite of this parasite invades host erythrocytes through interaction between its erythrocyte-binding proteins (EBPs) and their respective receptor on the erythrocytes. The regionII of P. knowlesi EBP, P. knowlesi beta (PkβII) protein is found to be mediating merozoite invasion into monkey erythrocytes by interacting with sialic acid receptors. Hence, the objective of this study was to investigate the genetic diversity, natural selection and haplotype grouping of PkβII of P. knowlesi isolates in Malaysia. Polymerase chain reaction amplifications of PkβII were performed on archived blood samples from Malaysia and 64 PkβII sequences were obtained. Sequence analysis revealed length polymorphism, and its amino acids at critical residues indicate the ability of PkβII to mediate P. knowlesi invasion into monkey erythrocytes. Low genetic diversity (π = 0.007) was observed in the PkβII of Malaysia Borneo compared to Peninsular Malaysia (π = 0.015). The PkβII was found to be under strong purifying selection to retain infectivity in monkeys and it plays a limited role in the zoonotic potential of P. knowlesi. Its haplotypes could be clustered into Peninsular Malaysia and Malaysia Borneo groups, indicating the existence of two distinct P. knowlesi parasites in Malaysia as reported in an earlier study.
  18. Ooi CH, Ling YP, Abdullah WZ, Mustafa AZ, Pung SY, Yeoh FY
    J Mater Sci Mater Med, 2019 Mar 30;30(4):44.
    PMID: 30929088 DOI: 10.1007/s10856-019-6247-5
    Hydroxyapatite is an ideal biomaterial for bone tissue engineering due to its biocompatibility and hemocompatibility which have been widely studied by many researchers. The incorporation of nanoporosity into hydroxyapatite could transform the biomaterial into an effective adsorbent for uremic toxins removal especially in artificial kidney system. However, the effect of nanoporosity incorporation on the hemocompatibility of hydroxyapatite has yet to be answered. In this study, nanoporous hydroxyapatite was synthesized using hydrothermal technique and its hemocompatibility was determined. Non-ionic surfactants were used as soft templates to create porosity in the hydroxyapatite. The presence of pure hydroxyapatite phase in the synthesized samples is validated by X-ray diffraction analysis and Fourier transform infrared spectroscopy. The TEM images show that the hydroxyapatite formed rod-like particles with the length of 21-90 nm and diameter of 11-70 nm. The hydroxyapatite samples exhibit BET surface area of 33-45 m2 g-1 and pore volume of 0.35-0.44 cm3 g-1. The hemocompatibility of the hydroxyapatite was determined via hemolysis test, platelet adhesion, platelet activation and blood clotting time measurement. The nanoporous hydroxyapatite shows less than 5% hemolysis, suggesting that the sample is highly hemocompatible. There is no activation and morphological change observed on the platelets adhered onto the hydroxyapatite. The blood clotting time demonstrates that the blood incubated with the hydroxyapatite did not coagulate. This study summarizes that the synthesized nanoporous hydroxyapatite is a highly hemocompatible biomaterial and could potentially be utilized in biomedical applications.
  19. Kamaruddin HK, Ooi CH, Mündel T, Aziz AR, Che Muhamed AM
    Eur. J. Appl. Physiol., 2019 Aug;119(8):1711-1723.
    PMID: 31098832 DOI: 10.1007/s00421-019-04161-2
    PURPOSE: To examine the effect of carbohydrate (CHO) mouth rinsing on endurance running responses and performance in dehydrated individuals.

    METHODS: In a double blind, randomised crossover design, 12 well-trained male runners completed 4 running time to exhaustion (TTE) trials at a speed equivalent to 70% of VO2peak in a thermoneutral condition. Throughout each run, participants mouth rinsed and expectorated every 15 min either 25 mL of 6% CHO or a placebo (PLA) solution for 10 s. The four TTEs consisted of two trials in the euhydrated (EU-CHO and EU-PLA) and two trials in the dehydrated (DY-CHO and DY-PLA) state. Prior to each TTE run, participants were dehydrated via exercise and allowed a passive rest period during which they were fed and either rehydrated equivalent to their body mass deficit (i.e., EU trials) or ingested only 50 mL of water (DY trials).

    RESULTS: CHO mouth rinsing significantly improved TTE performance in the DY compared to the EU trials (78.2 ± 4.3 vs. 76.9 ± 3.8 min, P = 0.02). The arousal level of the runners was significantly higher in the DY compared to the EU trials (P = 0.02). There was no significant difference among trials in heart rate, plasma glucose and lactate, and psychological measures.

    CONCLUSIONS: CHO mouth rinsing enhanced running performance significantly more when participants were dehydrated vs. euhydrated due to the greater sensitivity of oral receptors related to thirst and central mediated activation. These results show that level of dehydration alters the effect of brain perception with presence of CHO.

  20. Ooi CH, Tan A, Ahmad A, Kwong KW, Sompong R, Ghazali KA, et al.
    J Sports Sci, 2009 Dec;27(14):1591-9.
    PMID: 19967588 DOI: 10.1080/02640410903352907
    The aims of this study were to establish the physical and physiological attributes of elite and sub-elite Malaysian male badminton players and to determine whether these attributes discriminate elite players from sub-elite players. Measurements and tests of basic anthropometry, explosive power, anaerobic recovery capacity, badminton-specific movement agility, maximum strength, and aerobic capacity were conducted on two occasions, separated by at least one day. The elite (n = 12) and sub-elite (n = 12) players' characteristics were, respectively: mean age 24.6 years (s = 3.7) and 20.5 years (s = 0.7); mass 73.2 kg (s = 7.6) and 62.7 kg (s = 4.2); stature 1.76 m (s = 0.07) and 1.71 m (s = 0.05); body fat 12.5% (s = 4.8) and 9.5% (s = 3.4); estimated VO(2max) 56.9 ml . kg(-1) . min(-1) (s = 3.7) and 59.5 ml . kg(-1) . min(-1) (s = 5.2). The elite players had greater maximum absolute strength in one-repetition maximum bench press (P = 0.015) compared with the sub-elite players. There were significant differences in instantaneous lower body power estimated from vertical jump height between the elite and sub-elite groups (P < 0.01). However, there was no significant difference between groups in shuttle run tests and on-court badminton-specific movement agility tests. Our results show that elite Malaysian male badminton players are taller, heavier, and stronger than their sub-elite counterparts. The test battery, however, did not allow us to discriminate between the elite and sub-elite players, suggesting that at the elite level tactical knowledge, technical skills, and psychological readiness could be of greater importance.
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