Previous studies have reported the positive effects of branched-chain amino acids (BCAAs) supplem... more Previous studies have reported the positive effects of branched-chain amino acids (BCAAs) supplementation on lowering plasma markers of muscle damage and subjective soreness after resistance exercise. However, a variety of factors can potentially moderate its efficacy. This meta-analysis aimed to summarize the evidence regarding the effect of BCAAs supplementation on plasma muscle damage markers and soreness after resistance exercise in only trained males, by considering the plasma lactate dehydrogenase (LDH) and creatine kinase (CK). Randomized controlled trials were identified through a computerized literature search for the period 2010–2020. The pooled data were analyzed with the random-effects model and heterogeneity using I2. Cochrane Collaboration tools was used for the assessment of risk of bias. Nine studies met the inclusion criteria. A positive effect was found for CK at <24, 24, and 48 h after exercise and for muscle soreness at <24 h only. However, the positive eff...
International Journal of Environmental Research and Public Health, 2022
Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulat... more Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulates during hypoxia and muscle contraction. Tobacco smoking significantly increases blood lactate. Here we conducted a counter-balanced crossover study to examine whether this effect is associated with inhaling nicotine or burned carbon particles. Fifteen male smokers (aged 23 to 26 years) were randomized into 3 inhalation conditions: tobacco smoking, nicotine vaping, and nicotine-free vaping, conducted two days apart. An electronic thermal evaporator (e-cigarette) was used for vaping. We have observed an increased blood lactate (+62%, main effect: p < 0.01) and a decreased blood glucose (−12%, main effect: p < 0.05) during thermal air inhalations regardless of the content delivered. Exercise-induced lactate accumulation and shuttle run performance were similar for the 3 inhalation conditions. Tobacco smoking slightly increased the resting heart rate above the two vaping conditions (...
This review evaluated the effects of milk-based protein supplementation on resistance training (R... more This review evaluated the effects of milk-based protein supplementation on resistance training (RT)-induced gains in lean body mass or fat free mass (LBM/FFM) and muscle strength for older adults. A systematic search of PubMed, Scopus and EBSCOhost/SPORTDiscus was conducted. Eligibility criteria: Randomized controlled trials comparing all types of milk-based protein supplements with control supplements for the training older adults at mean age ≥ 60 y. Twenty studies were included in the qualitative synthesis, whilst seventeen studies were included in the quantitative synthesis. A dose of 10–15 g of milk protein supplementation was sufficient to augment RT-induced LBM/FFM. Intriguingly, four out of five studies show negative effect of whey protein supplementation at the same dose range (or even higher) compared with control supplementation (−0.49 kg, 95% CI: −0.69, −0.29, I2 = 14%, Z = 4.82, p < 0.001). For milk-based protein supplementation, RT-induced improvements in muscle stre...
High protein supplementation facilitates weight training induced bone mineralization in baseball ... more High protein supplementation facilitates weight training induced bone mineralization in baseball players, Nutrition (2020), doi:
This study examined whether deep ocean mineral (DOM) supplementation improved high-intensity inte... more This study examined whether deep ocean mineral (DOM) supplementation improved high-intensity intermittent running capacity after short-term recovery from an initial bout of prolonged high-intensity running in thermoneutral environmental conditions. Nine healthy recreational male soccer players (age: 22 ± 1 y; stature: 181 ± 5 cm; and body mass 80 ± 11 kg) completed a graded incremental test to ascertain peak oxygen uptake (V·O2PEAK), two familiarisation trials, and two experimental trials following a double-blind, repeated measures, crossover and counterbalanced design. All trials were separated by seven days and at ambient room temperature (i.e., 20 °C). During the 2 h recovery period after the initial ~60 min running at 75% V·O2PEAK, participants were provided with 1.38 ± 0.51 L of either deep ocean mineral water (DOM) or a taste-matched placebo (PLA), both mixed with 6% sucrose. DOM increased high-intensity running capacity by ~25% compared to PLA. There were no differences betwe...
This study examined the effects of exercise intervention on the quality of life (QoL), social fun... more This study examined the effects of exercise intervention on the quality of life (QoL), social functioning (SF), and physical functioning (PF) of breast cancer survivors, and identified the responsible and optimal exercise characteristics for amelioration of outcomes. Randomized controlled trials (RCTs) that adopted exercise intervention and measured the QoL, SF, and PF of breast cancer patients were included. We used meta-analysis to calculate the pooled effect, and meta-regression to identify the responsible exercise characteristics (type, frequency, duration, and time). Subgroup analysis assessed the optimal “time of session” for an improved QoL. The Cochrane risk-of-bias tool was used to determine the quality of studies. In the systematic review, we included 26 RCTs with a total of 1892 breast cancer patients, whilst 18 trials were considered for meta-analysis (exercise = 602; control = 603). The pooled effect showed that exercise intervention substantially improved the QoL (stan...
It remains unclear how exercise, as an entropic event, brings benefit against human aging. Here w... more It remains unclear how exercise, as an entropic event, brings benefit against human aging. Here we examined longitudinal changes of p16 senescent cells in skeletal muscle of young men (aged 22.5±1.7 y) before and after resistance exercise (0 h and 48 h) with multiple biopsies at two different protein availabilities: low protein (14%) and isocaloric high protein (44%) supplemented conditions. Immunohistochemistry analysis of muscle cross-sections using p16 and CD34 antibodies confirmed that the detected senescent cells were endothelial progenitor cells. Leukocyte infiltration into skeletal muscle increased during resistance exercise. The senescent cells in muscle decreased (-48%, P < 0.01) after exercise for 48 h. Low protein supplementation resulted in greater infiltrations of both CD68 phagocytic macrophage and leukocyte, further decreased p16 senescent cells (-73%, P < 0.001), and delayed increases in regenerative CD163 macrophage in skeletal muscle, compared with high prote...
Recently, a survey by the Centers for Disease Control and Prevention (CDC) reported that nearly 9... more Recently, a survey by the Centers for Disease Control and Prevention (CDC) reported that nearly 90% of U.S. adult smokers began smoking at the age of 18. This demonstrates that the exposure to environmental tobacco smoke (ETS) of youngsters today is changing from passive smoking to active smoking (direct inhalation of tobacco). In the current study, an investigation of ETS exposure in young C57BL mice was conducted. After 6 weeks of ETS exposure, the Sirt-1 protein level was decreased and cardiac autophagy was increased in C57BL mice. Furthermore, the IGF2R cardiac hypertrophy signaling pathway was also triggered, although cardiac apoptosis and hypertrophy were not induced. Youngsters' desire to look more mature is one of the psychological factors that impacts smoking amongst young people. Our results suggest that though ETS exposure might cause cardiac autophagy amongst youngsters, the loss of the longevity Sirt-1 protein and the increase in IGF2R cardiac hypertrophy signaling could still promote heart diseases that are age-specific.
Canadian Journal of Physiology and Pharmacology, 2016
Fat burning, defined by fatty acid oxidation into carbon dioxide, is the most described hypothesi... more Fat burning, defined by fatty acid oxidation into carbon dioxide, is the most described hypothesis to explain the actual abdominal fat reducing outcome of exercise training. This hypothesis is strengthened by evidence of increased whole-body lipolysis during exercise. As a result, aerobic training is widely recommended for obesity management. This intuition raises several paradoxes: first, both aerobic and resistance exercise training do not actually elevate 24 h fat oxidation, according to data from chamber-based indirect calorimetry. Second, anaerobic high-intensity intermittent training produces greater abdominal fat reduction than continuous aerobic training at similar amounts of energy expenditure. Third, significant body fat reduction in athletes occurs when oxygen supply decreases to inhibit fat burning during altitude-induced hypoxia exposure at the same training volume. Lack of oxygen increases post-meal blood distribution to human skeletal muscle, suggesting that shifting ...
Present study examined the effects of conjugated linoleic acid (CLA) supplementation on glycogen ... more Present study examined the effects of conjugated linoleic acid (CLA) supplementation on glycogen resynthesis in exercised human skeletal muscle. Twelve male participants completed a cross-over trial with CLA (3.8 g/day for 8 week) or placebo supplements by separation of 8 weeks. CLA is a mixture of trans-10 cis-12 and cis-9 trans-11 isomers (50:50). On experiment day, all participants performed 60-min cycling exercise at 75% VO2 max, then consumed a carbohydrate meal immediately after exercise and recovered for 3 h. Biopsied muscle samples from vastus lateralis were obtained immediately (0 h) and 3 h following exercise. Simultaneously, blood and gaseous samples were collected for every 30 min during 3-h recovery. Results showed significantly increased muscle glycogen content with CLA after a single bout of exercise (P < 0.05). Muscle glucose transporter type 4 expression was significantly elevated immediately after exercise, and this elevation was continued until 3 h after exerci...
Brain ischemia leads to muscle inactivity-induced atrophy and may exacerbate motor function defic... more Brain ischemia leads to muscle inactivity-induced atrophy and may exacerbate motor function deficits. Intramuscular insulin-like growth factor I (IGF-I) injection has been shown to alleviate the brain ischemia-induced muscle atrophy and thus improve the motor function. Motor function is normally gauged by the integrity and coordination of the central nervous system and peripheral muscles. Whether brain ischemic regions are adaptively changed by the intramuscular IGF-I injection is not well understood. In this study, the effect of intramuscular IGF-I injection was examined on the central nervous system of brain ischemic rats. Rats were divided into 4 groups: sham control, brain ischemia control, brain ischemia with IGF-I treatment, and brain ischemia with IGF-I plus IGF-I receptor inhibitor treatment. Brain ischemia was induced by right middle cerebral artery occlusion. IGF-I and an IGF-1 receptor inhibitor were injected into the affected calf and anterior tibialis muscles of the tre...
Circulating insulin concentration has been suggested as a biomarker for human longevity. The goal... more Circulating insulin concentration has been suggested as a biomarker for human longevity. The goal of the study was to determine the insulin levels under a glucose-challenged condition for the sedentary and physical active females in early middle age. We measured serum insulin levels for following groups: young sedentary (Y-SED, age 19.7 +/- 0.2 years), middle-aged sedentary (M-SED, age 42.3 +/- 3.1 years), young physically active (Y-EX, age 20.7 +/- 0.5 years), and middle-aged physically active (M-EX, age 40.3 +/- 2.8 years). Oral glucose tolerance test (OGTT) and insulin measurement were performed under overnight fasted condition. Triglyceride, cholesterol, body mass index (BMI), and waist-to-hip ratio (WHR) were also determined in all subjects. While fasted glucose and insulin levels were not different among 4 groups, glucose and insulin levels under OGTT were greater in the M-SED group than those in the Y-SED group. The M-EX subjects exhibited lower insulin levels on OGTT, as com...
The present study determined the interactive effect of an acute bout of resistance exercise and d... more The present study determined the interactive effect of an acute bout of resistance exercise and dehydroepiandrosterone (DHEA) administration on glucose tolerance and serum lipids. Twenty middle-aged female subjects performed an acute bout of resistance exercise and were subsequently divided into two groups: placebo (age 40.7 +/- 2.0) and DHEA administered (age 39.0 +/- 2.7). Ten subjects who received DHEA (age 41.5 +/- 4.6) participated in a non-exercise control. DHEA (25 mg twice daily) or placebo was orally supplemented for 48 hours. Before exercise and 48 hours after the last exercise bout (14 hours after the last DHEA intake), an oral glucose tolerance test and an insulin concentration were determined. Levels of fasting serum cholesterol and triglyceride, tumor necrosis factor-alpha (TNF-alpha), creatine kinase (CK) were also measured. The DHEA administration significantly elevated the fasting dehydroepiandrosterone sulfate (DHEA-S) level by approximately 3-fold. Both acute resi...
Diabetes is characterized by elevated blood glucose levels and disturbed homeostasis of metabolic... more Diabetes is characterized by elevated blood glucose levels and disturbed homeostasis of metabolic enzymes in whole-body. This study aimed to investigate the effect of ginger administration on altered blood glucose levels, intra- and extra-mitochondrial enzymes and tissue injuries in streptozotocin (STZ)-induced diabetic rats. Wistar strain rats (n = 30) were equally divided into 5 groups: normal control (NC), ginger treated (Gt, 200 mg/kg b.w. orally/30 days), diabetic control (DC, 50 mg/kg b.w.), diabetic plus ginger treated (D + Gt) and diabetic plus glibenclamide treated (D + Gli) groups. We found highly elevated blood glucose levels in the diabetic group, and the glucose levels were significantly (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) lowered by ginger administration. Activities of intra- and extra-mitochondrial enzymes such as glucose-6-phosphate dehydrogenase (G6PD), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and glutamate dehydrogenase (GDH) were significantly (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) decreased in the kidneys of the diabetic rats, while this was significantly reversed by 30 days of ginger treatment. We also observed consistent renal tissue damages in the diabetic rats; however, these injuries recovered in the ginger-treated diabetic rats as shown in histopathological studies. In this study, we demonstrated that an ethanolic extract of ginger could lower the blood glucose levels as well as improve activities of intra- and extra-mitochondrial enzymes in diabetic rats. Our results suggest that ginger extracts could be used as a nephro-protective supplement particularly to reverse diabetic-induced complications.
Objective: To investigate the effect of 2-month detraining on body composition and glucose tolera... more Objective: To investigate the effect of 2-month detraining on body composition and glucose tolerance for female collegiate dancers. Design: Longitudinal study of dancers who stopped their regular training for 2 months. Subjects: 16 female collegiate dancers (age: 19.770.11 year, body mass index (BMI): 20.770.56 kg/m 2). Measurements: BMI, waist-to-hip ratio (WHR), oral glucose tolerance test (OGTT), insulin response during OGTT, and blood lipids at baseline and after a 2-month detraining. Results: Glucose tolerance was not significantly affected by the detraining, but the fasted insulin and insulin levels during OGTT were significantly elevated. Fasted free fatty acid (FFA) and triglyceride levels were significantly elevated without change in cholesterol level. BMI was not significantly altered during this detraining period, but the waist circumference and WHR ratio were significantly elevated. Conclusion: Only a 2-month cessation of regular training in female dancers significantly elevated basal and postprandial insulin levels and triglycerides, and were associated with increased basal FFA. This result appears to be partly related to the increased central fatness but not body mass, indicating that the early development of obesity due to reduced physical activity may not necessarily reflect on weight status. A warning is thus warranted for those young women who depend on weight measurement for body fat status monitoring.
VO2peak improved by 1.73 and 1.93 mLO2/kg/min with A and A+R respectively compared to C (p<0.05).... more VO2peak improved by 1.73 and 1.93 mLO2/kg/min with A and A+R respectively compared to C (p<0.05). This was paralleled by improvements in workload (23.6 and 19.8 W for A and A+R respectively) as well as significant changes in treadmill time (1.2 and 1.1 min for A and A+R respectively) (p<0.05). Strength improvements were observed after A but gains were greater following A+R and R on the leg press (A+R:48%, R:65%) bench press (A+R:38%, R:57%) and seated row (A+R:33%, R:41%)(p<0.05). There was no main effect of age or sex on training performance outcomes. There was however a tendency for older participants to increase VO2peak more with A+R (+1.5 mLO2/kg/min) than with A only (+0.7 mLO2/kg/min) whereas improvements among younger participants were similar between A+R (+1.71 mLO2/kg/min) and A (+1.91 mLO2/kg/min). CONCLUSION: Aerobic training improved cardiorespiratory fitness and resistance training improved strength. Combined training did not provide any additional benefits nor did it mitigate improvements in fitness in younger subjects. In older subjects, there was a trend to greater aerobic fitness gains with combined training versus aerobic training alone.
Journal of the International Society of Sports Nutrition, 2012
Background Previous studies reported divergent results on nutraceutical actions and free radical ... more Background Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1) on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress. Methods Forty weight-matched rats were evenly divided into control (N = 20) and Rg1 (N = 20) groups. Rg1 was orally administered at the dose of 0.1 mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA) muscles were surgically collected immediately after exercise along with non-exercise rats. Results Exhaustive exercise significantly (p<0.05) increased the lipid peroxidation of co...
Previous studies have reported the positive effects of branched-chain amino acids (BCAAs) supplem... more Previous studies have reported the positive effects of branched-chain amino acids (BCAAs) supplementation on lowering plasma markers of muscle damage and subjective soreness after resistance exercise. However, a variety of factors can potentially moderate its efficacy. This meta-analysis aimed to summarize the evidence regarding the effect of BCAAs supplementation on plasma muscle damage markers and soreness after resistance exercise in only trained males, by considering the plasma lactate dehydrogenase (LDH) and creatine kinase (CK). Randomized controlled trials were identified through a computerized literature search for the period 2010–2020. The pooled data were analyzed with the random-effects model and heterogeneity using I2. Cochrane Collaboration tools was used for the assessment of risk of bias. Nine studies met the inclusion criteria. A positive effect was found for CK at <24, 24, and 48 h after exercise and for muscle soreness at <24 h only. However, the positive eff...
International Journal of Environmental Research and Public Health, 2022
Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulat... more Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulates during hypoxia and muscle contraction. Tobacco smoking significantly increases blood lactate. Here we conducted a counter-balanced crossover study to examine whether this effect is associated with inhaling nicotine or burned carbon particles. Fifteen male smokers (aged 23 to 26 years) were randomized into 3 inhalation conditions: tobacco smoking, nicotine vaping, and nicotine-free vaping, conducted two days apart. An electronic thermal evaporator (e-cigarette) was used for vaping. We have observed an increased blood lactate (+62%, main effect: p < 0.01) and a decreased blood glucose (−12%, main effect: p < 0.05) during thermal air inhalations regardless of the content delivered. Exercise-induced lactate accumulation and shuttle run performance were similar for the 3 inhalation conditions. Tobacco smoking slightly increased the resting heart rate above the two vaping conditions (...
This review evaluated the effects of milk-based protein supplementation on resistance training (R... more This review evaluated the effects of milk-based protein supplementation on resistance training (RT)-induced gains in lean body mass or fat free mass (LBM/FFM) and muscle strength for older adults. A systematic search of PubMed, Scopus and EBSCOhost/SPORTDiscus was conducted. Eligibility criteria: Randomized controlled trials comparing all types of milk-based protein supplements with control supplements for the training older adults at mean age ≥ 60 y. Twenty studies were included in the qualitative synthesis, whilst seventeen studies were included in the quantitative synthesis. A dose of 10–15 g of milk protein supplementation was sufficient to augment RT-induced LBM/FFM. Intriguingly, four out of five studies show negative effect of whey protein supplementation at the same dose range (or even higher) compared with control supplementation (−0.49 kg, 95% CI: −0.69, −0.29, I2 = 14%, Z = 4.82, p < 0.001). For milk-based protein supplementation, RT-induced improvements in muscle stre...
High protein supplementation facilitates weight training induced bone mineralization in baseball ... more High protein supplementation facilitates weight training induced bone mineralization in baseball players, Nutrition (2020), doi:
This study examined whether deep ocean mineral (DOM) supplementation improved high-intensity inte... more This study examined whether deep ocean mineral (DOM) supplementation improved high-intensity intermittent running capacity after short-term recovery from an initial bout of prolonged high-intensity running in thermoneutral environmental conditions. Nine healthy recreational male soccer players (age: 22 ± 1 y; stature: 181 ± 5 cm; and body mass 80 ± 11 kg) completed a graded incremental test to ascertain peak oxygen uptake (V·O2PEAK), two familiarisation trials, and two experimental trials following a double-blind, repeated measures, crossover and counterbalanced design. All trials were separated by seven days and at ambient room temperature (i.e., 20 °C). During the 2 h recovery period after the initial ~60 min running at 75% V·O2PEAK, participants were provided with 1.38 ± 0.51 L of either deep ocean mineral water (DOM) or a taste-matched placebo (PLA), both mixed with 6% sucrose. DOM increased high-intensity running capacity by ~25% compared to PLA. There were no differences betwe...
This study examined the effects of exercise intervention on the quality of life (QoL), social fun... more This study examined the effects of exercise intervention on the quality of life (QoL), social functioning (SF), and physical functioning (PF) of breast cancer survivors, and identified the responsible and optimal exercise characteristics for amelioration of outcomes. Randomized controlled trials (RCTs) that adopted exercise intervention and measured the QoL, SF, and PF of breast cancer patients were included. We used meta-analysis to calculate the pooled effect, and meta-regression to identify the responsible exercise characteristics (type, frequency, duration, and time). Subgroup analysis assessed the optimal “time of session” for an improved QoL. The Cochrane risk-of-bias tool was used to determine the quality of studies. In the systematic review, we included 26 RCTs with a total of 1892 breast cancer patients, whilst 18 trials were considered for meta-analysis (exercise = 602; control = 603). The pooled effect showed that exercise intervention substantially improved the QoL (stan...
It remains unclear how exercise, as an entropic event, brings benefit against human aging. Here w... more It remains unclear how exercise, as an entropic event, brings benefit against human aging. Here we examined longitudinal changes of p16 senescent cells in skeletal muscle of young men (aged 22.5±1.7 y) before and after resistance exercise (0 h and 48 h) with multiple biopsies at two different protein availabilities: low protein (14%) and isocaloric high protein (44%) supplemented conditions. Immunohistochemistry analysis of muscle cross-sections using p16 and CD34 antibodies confirmed that the detected senescent cells were endothelial progenitor cells. Leukocyte infiltration into skeletal muscle increased during resistance exercise. The senescent cells in muscle decreased (-48%, P < 0.01) after exercise for 48 h. Low protein supplementation resulted in greater infiltrations of both CD68 phagocytic macrophage and leukocyte, further decreased p16 senescent cells (-73%, P < 0.001), and delayed increases in regenerative CD163 macrophage in skeletal muscle, compared with high prote...
Recently, a survey by the Centers for Disease Control and Prevention (CDC) reported that nearly 9... more Recently, a survey by the Centers for Disease Control and Prevention (CDC) reported that nearly 90% of U.S. adult smokers began smoking at the age of 18. This demonstrates that the exposure to environmental tobacco smoke (ETS) of youngsters today is changing from passive smoking to active smoking (direct inhalation of tobacco). In the current study, an investigation of ETS exposure in young C57BL mice was conducted. After 6 weeks of ETS exposure, the Sirt-1 protein level was decreased and cardiac autophagy was increased in C57BL mice. Furthermore, the IGF2R cardiac hypertrophy signaling pathway was also triggered, although cardiac apoptosis and hypertrophy were not induced. Youngsters' desire to look more mature is one of the psychological factors that impacts smoking amongst young people. Our results suggest that though ETS exposure might cause cardiac autophagy amongst youngsters, the loss of the longevity Sirt-1 protein and the increase in IGF2R cardiac hypertrophy signaling could still promote heart diseases that are age-specific.
Canadian Journal of Physiology and Pharmacology, 2016
Fat burning, defined by fatty acid oxidation into carbon dioxide, is the most described hypothesi... more Fat burning, defined by fatty acid oxidation into carbon dioxide, is the most described hypothesis to explain the actual abdominal fat reducing outcome of exercise training. This hypothesis is strengthened by evidence of increased whole-body lipolysis during exercise. As a result, aerobic training is widely recommended for obesity management. This intuition raises several paradoxes: first, both aerobic and resistance exercise training do not actually elevate 24 h fat oxidation, according to data from chamber-based indirect calorimetry. Second, anaerobic high-intensity intermittent training produces greater abdominal fat reduction than continuous aerobic training at similar amounts of energy expenditure. Third, significant body fat reduction in athletes occurs when oxygen supply decreases to inhibit fat burning during altitude-induced hypoxia exposure at the same training volume. Lack of oxygen increases post-meal blood distribution to human skeletal muscle, suggesting that shifting ...
Present study examined the effects of conjugated linoleic acid (CLA) supplementation on glycogen ... more Present study examined the effects of conjugated linoleic acid (CLA) supplementation on glycogen resynthesis in exercised human skeletal muscle. Twelve male participants completed a cross-over trial with CLA (3.8 g/day for 8 week) or placebo supplements by separation of 8 weeks. CLA is a mixture of trans-10 cis-12 and cis-9 trans-11 isomers (50:50). On experiment day, all participants performed 60-min cycling exercise at 75% VO2 max, then consumed a carbohydrate meal immediately after exercise and recovered for 3 h. Biopsied muscle samples from vastus lateralis were obtained immediately (0 h) and 3 h following exercise. Simultaneously, blood and gaseous samples were collected for every 30 min during 3-h recovery. Results showed significantly increased muscle glycogen content with CLA after a single bout of exercise (P < 0.05). Muscle glucose transporter type 4 expression was significantly elevated immediately after exercise, and this elevation was continued until 3 h after exerci...
Brain ischemia leads to muscle inactivity-induced atrophy and may exacerbate motor function defic... more Brain ischemia leads to muscle inactivity-induced atrophy and may exacerbate motor function deficits. Intramuscular insulin-like growth factor I (IGF-I) injection has been shown to alleviate the brain ischemia-induced muscle atrophy and thus improve the motor function. Motor function is normally gauged by the integrity and coordination of the central nervous system and peripheral muscles. Whether brain ischemic regions are adaptively changed by the intramuscular IGF-I injection is not well understood. In this study, the effect of intramuscular IGF-I injection was examined on the central nervous system of brain ischemic rats. Rats were divided into 4 groups: sham control, brain ischemia control, brain ischemia with IGF-I treatment, and brain ischemia with IGF-I plus IGF-I receptor inhibitor treatment. Brain ischemia was induced by right middle cerebral artery occlusion. IGF-I and an IGF-1 receptor inhibitor were injected into the affected calf and anterior tibialis muscles of the tre...
Circulating insulin concentration has been suggested as a biomarker for human longevity. The goal... more Circulating insulin concentration has been suggested as a biomarker for human longevity. The goal of the study was to determine the insulin levels under a glucose-challenged condition for the sedentary and physical active females in early middle age. We measured serum insulin levels for following groups: young sedentary (Y-SED, age 19.7 +/- 0.2 years), middle-aged sedentary (M-SED, age 42.3 +/- 3.1 years), young physically active (Y-EX, age 20.7 +/- 0.5 years), and middle-aged physically active (M-EX, age 40.3 +/- 2.8 years). Oral glucose tolerance test (OGTT) and insulin measurement were performed under overnight fasted condition. Triglyceride, cholesterol, body mass index (BMI), and waist-to-hip ratio (WHR) were also determined in all subjects. While fasted glucose and insulin levels were not different among 4 groups, glucose and insulin levels under OGTT were greater in the M-SED group than those in the Y-SED group. The M-EX subjects exhibited lower insulin levels on OGTT, as com...
The present study determined the interactive effect of an acute bout of resistance exercise and d... more The present study determined the interactive effect of an acute bout of resistance exercise and dehydroepiandrosterone (DHEA) administration on glucose tolerance and serum lipids. Twenty middle-aged female subjects performed an acute bout of resistance exercise and were subsequently divided into two groups: placebo (age 40.7 +/- 2.0) and DHEA administered (age 39.0 +/- 2.7). Ten subjects who received DHEA (age 41.5 +/- 4.6) participated in a non-exercise control. DHEA (25 mg twice daily) or placebo was orally supplemented for 48 hours. Before exercise and 48 hours after the last exercise bout (14 hours after the last DHEA intake), an oral glucose tolerance test and an insulin concentration were determined. Levels of fasting serum cholesterol and triglyceride, tumor necrosis factor-alpha (TNF-alpha), creatine kinase (CK) were also measured. The DHEA administration significantly elevated the fasting dehydroepiandrosterone sulfate (DHEA-S) level by approximately 3-fold. Both acute resi...
Diabetes is characterized by elevated blood glucose levels and disturbed homeostasis of metabolic... more Diabetes is characterized by elevated blood glucose levels and disturbed homeostasis of metabolic enzymes in whole-body. This study aimed to investigate the effect of ginger administration on altered blood glucose levels, intra- and extra-mitochondrial enzymes and tissue injuries in streptozotocin (STZ)-induced diabetic rats. Wistar strain rats (n = 30) were equally divided into 5 groups: normal control (NC), ginger treated (Gt, 200 mg/kg b.w. orally/30 days), diabetic control (DC, 50 mg/kg b.w.), diabetic plus ginger treated (D + Gt) and diabetic plus glibenclamide treated (D + Gli) groups. We found highly elevated blood glucose levels in the diabetic group, and the glucose levels were significantly (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001) lowered by ginger administration. Activities of intra- and extra-mitochondrial enzymes such as glucose-6-phosphate dehydrogenase (G6PD), succinate dehydrogenase (SDH), malate dehydrogenase (MDH) and glutamate dehydrogenase (GDH) were significantly (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) decreased in the kidneys of the diabetic rats, while this was significantly reversed by 30 days of ginger treatment. We also observed consistent renal tissue damages in the diabetic rats; however, these injuries recovered in the ginger-treated diabetic rats as shown in histopathological studies. In this study, we demonstrated that an ethanolic extract of ginger could lower the blood glucose levels as well as improve activities of intra- and extra-mitochondrial enzymes in diabetic rats. Our results suggest that ginger extracts could be used as a nephro-protective supplement particularly to reverse diabetic-induced complications.
Objective: To investigate the effect of 2-month detraining on body composition and glucose tolera... more Objective: To investigate the effect of 2-month detraining on body composition and glucose tolerance for female collegiate dancers. Design: Longitudinal study of dancers who stopped their regular training for 2 months. Subjects: 16 female collegiate dancers (age: 19.770.11 year, body mass index (BMI): 20.770.56 kg/m 2). Measurements: BMI, waist-to-hip ratio (WHR), oral glucose tolerance test (OGTT), insulin response during OGTT, and blood lipids at baseline and after a 2-month detraining. Results: Glucose tolerance was not significantly affected by the detraining, but the fasted insulin and insulin levels during OGTT were significantly elevated. Fasted free fatty acid (FFA) and triglyceride levels were significantly elevated without change in cholesterol level. BMI was not significantly altered during this detraining period, but the waist circumference and WHR ratio were significantly elevated. Conclusion: Only a 2-month cessation of regular training in female dancers significantly elevated basal and postprandial insulin levels and triglycerides, and were associated with increased basal FFA. This result appears to be partly related to the increased central fatness but not body mass, indicating that the early development of obesity due to reduced physical activity may not necessarily reflect on weight status. A warning is thus warranted for those young women who depend on weight measurement for body fat status monitoring.
VO2peak improved by 1.73 and 1.93 mLO2/kg/min with A and A+R respectively compared to C (p<0.05).... more VO2peak improved by 1.73 and 1.93 mLO2/kg/min with A and A+R respectively compared to C (p<0.05). This was paralleled by improvements in workload (23.6 and 19.8 W for A and A+R respectively) as well as significant changes in treadmill time (1.2 and 1.1 min for A and A+R respectively) (p<0.05). Strength improvements were observed after A but gains were greater following A+R and R on the leg press (A+R:48%, R:65%) bench press (A+R:38%, R:57%) and seated row (A+R:33%, R:41%)(p<0.05). There was no main effect of age or sex on training performance outcomes. There was however a tendency for older participants to increase VO2peak more with A+R (+1.5 mLO2/kg/min) than with A only (+0.7 mLO2/kg/min) whereas improvements among younger participants were similar between A+R (+1.71 mLO2/kg/min) and A (+1.91 mLO2/kg/min). CONCLUSION: Aerobic training improved cardiorespiratory fitness and resistance training improved strength. Combined training did not provide any additional benefits nor did it mitigate improvements in fitness in younger subjects. In older subjects, there was a trend to greater aerobic fitness gains with combined training versus aerobic training alone.
Journal of the International Society of Sports Nutrition, 2012
Background Previous studies reported divergent results on nutraceutical actions and free radical ... more Background Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1) on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress. Methods Forty weight-matched rats were evenly divided into control (N = 20) and Rg1 (N = 20) groups. Rg1 was orally administered at the dose of 0.1 mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA) muscles were surgically collected immediately after exercise along with non-exercise rats. Results Exhaustive exercise significantly (p<0.05) increased the lipid peroxidation of co...
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