Aziz A.R.,Singapore Sports Institute |
Slater G.J.,University of The Sunshine Coast |
Chia M.Y.H.,Nanyang Technological University |
Teh K.C.,Sports Medicine Center
Science and Sports | Year: 2012
Objectives: The purpose of this study was to determine if aerobic and anaerobic training-induced adaptations were compromised as a result of Ramadan fasting. Methods: Twenty adolescent males of the Muslim and non-Muslim faith were divided into fasting (FAS, n= 10) and non-fasting or control (CON, n= 10) groups, respectively. High-intensity interval cycle exercise training was conducted three times per week for seven weeks, with Ramadan fasting falling during training weeks 3 to 6 for the FAS group. Results: Both groups significantly improved their peak oxygen uptake (VO 2peak; FAS 2.77±0.33 to 3.08±0.22 and CON 2.61±0.22 to 2.89±0.21L/min) and maximal anaerobic performance (total work during four Wingate bouts; FAS 53.4±5.2 to 57.7±4.8 and CON 47.4±4.5 to 52.0±4.5kJ) (all p<0.05). There were no significant differences in the magnitude of improvements made between groups, either for aerobic (FAS 0.31±0.28 vs. CON 0.28±0.12L/min) or anaerobic (FAS 4.3±3.3 vs. CON 4.6±3.4kJ) performance (all p>0.05). Indices of training intensity (mean heart rate and mean blood lactate) and mean daily energy and fluid intake were not significantly different between groups throughout the study period. Conclusions: Aerobic and anaerobic adaptations to seven weeks of training were not compromised by four weeks of intermittent Ramadan fasting, possibly because the overall training intensity and nutrient intake were maintained throughout the Ramadan period. © 2011 Elsevier Masson SAS.
Yeh Y.J.,National University of Singapore |
Law L.Y.L.,Defence Medical and Environmental Research Institute |
Lim C.L.,National University of Singapore |
Lim C.L.,Singapore Sports Institute
European Journal of Applied Physiology | Year: 2013
This study investigated plasma lipopolysaccharides (LPS) concentration and intestinal permeability after 60-min run at 70 % maximum oxygen uptake (VO 2max) in hot [33 C, 50 % relative humidity (rH)] and cool (22 C, 62 % rH) conditions. Fifteen volunteers gave their informed consent to participate in this study. Their venous blood samples were taken before, after, 2 and 5 h after exercise in each of the conditions. The order of the two environmental conditions in which they exercised in was randomised and counterbalanced. Plasma LPS concentration increased by an average of 54.0 % (95 % confidence interval: 30.7, 75.1 %) after exercising in the hot trial but no significant changes were observed in cool trial, where mean plasma LPS concentration was 12.0 ± 6.4 pg mL-1 (before), 10.9 ± 5.4 pg mL-1 (after), 10.7 ± 6.0 pg mL-1 (2 h after) and 10.6 ± 5.7 pg mL-1 (5 h after). Median (range) plasma claudin-3 (CLDN3) concentration was significantly higher after exercise (hot: 8.2 [1.0-13.0] ng mL-1 and cool: 7.6 [0.6-13.4] ng mL-1) as compared to before exercise (hot: 6.6 [0.7-11.8] ng mL-1 and cool: 6.7 [0.8-12.6] ng mL-1) (p < 0.05), but there is no significant difference observed between trials (p > 0.05). Changes in intestinal permeability are only affected by exercise while exercise-induced endotoxemia is affected by environmental conditions. This study, thus, highlights that an increase in intestinal permeability is not sufficient to trigger exercise-induced endotoxemia, suggesting that post-LPS translocation events may have a greater impact in its occurrence. © 2013 Springer-Verlag Berlin Heidelberg.
Lee M.J.C.,University of Western Australia |
Lee M.J.C.,Singapore Sports Institute |
Lloyd D.G.,University of Western Australia |
Lloyd D.G.,Griffith University |
And 3 more authors.
Medicine and Science in Sports and Exercise | Year: 2013
PURPOSE: Evasive sidestepping during sports commonly results in noncontact anterior cruciate ligament injuries. Sidestepping in response to different simple visual stimuli has been studied previously but never investigated using quasi-game-realistic visual conditions. We compared the biomechanics of high-level and low-level soccer players when sidestepping in response to projected, three-dimensional defender(s) and the traditionally used planned and unplanned arrow stimuli. METHODS: A three-dimensional motion analysis system captured the trunk and lower limb kinematics and ground reaction forces of 15 high-level and 15 low-level soccer players sidestepping in response to a one-defender scenario (1DS), two-defender scenario (2DS), arrow-planned condition (AP), and arrow-unplanned condition (AUNP). The temporal constraints imposed by the stimuli conditions resulted in increasing difficulty from AP, 1DS, 2DS, to AUNP. Selected joint kinematics and three-dimensional knee moments during the weight-acceptance phase of sidestepping were analyzed. RESULTS: Hip external rotation at initial foot contact was smaller when participants sidestepped in response to the projected defenders versus arrow conditions. Hip abduction was smallest in the AP, moderate in the defender scenarios, and largest in the AUNP. Peak knee valgus moments were 25% larger in the defender scenarios and 70% larger in the AUNP compared with the AP. High-level players exhibited decreased hip abduction and knee valgus moments in the 2DS compared with the low-level players. CONCLUSIONS: Compared with the arrow conditions, sidestepping in response to the defender(s) resulted in different postures and knee moments, which further differentiated between high-level and low-level players in the complex 2DS. These findings highlight the effects of stimuli realism and complexity on the visual-perceptual-motor skill of sidestepping, which has implications for anterior cruciate ligament injury prevention. Copyright © 2013 by the American College of Sports Medicine.
Wylde M.J.,Performance Enhancement Institute |
Tan F.H.Y.,Singapore Sports Institute |
O'Donoghue P.G.,Cardiff Metropolitan University
International Journal of Performance Analysis in Sport | Year: 2013
This study sought to carry out a comprehensive time-motion analysis of elite women's foil fencing to understand the demands being placed on fencers in competition. A key part of this study was to identify the differences between 15-touch, 5-touch and team bouts. 100 international women's foil fencing bouts were analysed and five movement classifications were used during the data collection, which were consolidated into three categories of varying intensities for analysis. This study found that high-intensity movements accounted for 6.2 ± 2.5% of total bout time in elite women's foil fencing. These high-intensity movements had a mean duration of 0.7 ± 0.1 s with a mean recovery period of 10.4 ± 3.3 s. The only "large" difference between the bouts was found for the mean duration of the low-intensity movements in the 15- touch bouts. All other differences were "moderate", "small" or "trivial". These results suggest that similar training plans could be used to physically prepare fencers for 15-touch, 5-touch and team bouts and should consist of primarily anaerobic alactic and aerobic activities. This study has provided a basis from which further research could be carried out, while the movement classifications have a range of applications within the study of fencing.
Ihsan M.,Singapore Sports Institute |
Ihsan M.,Edith Cowan University |
Watson G.,University of Tasmania |
Abbiss C.R.,Edith Cowan University
Sports Medicine | Year: 2016
Intense training results in numerous physiological perturbations such as muscle damage, hyperthermia, dehydration and glycogen depletion. Insufficient/untimely restoration of these physiological alterations might result in sub-optimal performance during subsequent training sessions, while chronic imbalance between training stress and recovery might lead to overreaching or overtraining syndrome. The use of post-exercise cold water immersion (CWI) is gaining considerable popularity among athletes to minimize fatigue and accelerate post-exercise recovery. CWI, through its primary ability to decrease tissue temperature and blood flow, is purported to facilitate recovery by ameliorating hyperthermia and subsequent alterations to the central nervous system (CNS), reducing cardiovascular strain, removing accumulated muscle metabolic by-products, attenuating exercise-induced muscle damage (EIMD) and improving autonomic nervous system function. The current review aims to provide a comprehensive and detailed examination of the mechanisms underpinning acute and longer term recovery of exercise performance following post-exercise CWI. Understanding the mechanisms will aid practitioners in the application and optimisation of CWI strategies to suit specific recovery needs and consequently improve athletic performance. Much of the literature indicates that the dominant mechanism by which CWI facilitates short term recovery is via ameliorating hyperthermia and consequently CNS mediated fatigue and by reducing cardiovascular strain. In contrast, there is limited evidence to support that CWI might improve acute recovery by facilitating the removal of muscle metabolites. CWI has been shown to augment parasympathetic reactivation following exercise. While CWI-mediated parasympathetic reactivation seems detrimental to high-intensity exercise performance when performed shortly after, it has been shown to be associated with improved longer term physiological recovery and day to day training performances. The efficacy of CWI for attenuating the secondary effects of EIMD seems dependent on the mode of exercise utilised. For instance, CWI application seems to demonstrate limited recovery benefits when EIMD was induced by single-joint eccentrically biased contractions. In contrast, CWI seems more effective in ameliorating effects of EIMD induced by whole body prolonged endurance/intermittent based exercise modalities. © 2016 Springer International Publishing Switzerland