Journal of Exercise Nutrition & Biochemistry最新文献

Purpose: We conducted a meta-analysis to evaluate the effects of Taekwondo training on the physical fitness factors in Korean elementary students comprehensively and quantitatively.

Methods: We classified research studies published until November 2018 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and selected a total of 17 research items; a meta-analysis of these items was then conducted. We used the Comprehensive Meta-Analysis 3.0 and Review Manager 5.3 to analyze the mean effect size, study quality, and publication bias.

Results: Taekwondo training improved the cardiopulmonary endurance, muscle endurance, and power of the elementary students, but was not practical or less useful on other physical fitness factors. The meta-regression analysis of the cardiopulmonary endurance and power items showed that the effect size was large when the sample size was small. Therefore, it is necessary to consider the sample size in interpreting the effect size for these two items. Further, during correction of the publication bias for the power items, the improvement effect by Taekwondo training was eliminated.

Conclusion: Taekwondo training is helpful for improving the cardiopulmonary endurance and muscle endurance of Korean elementary students but is not useful for other physical fitness factors.

Purpose: The effect of acute nitrate supplementation on muscle fatigue is largely unknown. This study aimed to evaluate the effect of acute nitrate supplementation on muscle fatigue.

Methods: Thirty-five recreationally active subjects consumed 140 ml of beetroot (BR) juice (nitrate: 8 mmol·d-1) or placebo (PL) 12 and 2.5 hours before two exercise sessions. Peak torque was measured during 50 repetitions, at maximal effort, and during concentric knee extensions at 90°·s-1. Blood pressure (BP) was recorded pre- and post-exercise.

Results: Peak torque, maximum work, rate of fatigue, and rate of work fatigue were similar between the BR and PL conditions. Post-exercise diastolic BP (BR: 67.2 ± 9.8 vs. PL: 64.5 ± 7.9 mmHg, p < 0.05) and mean arterial pressure (BR: 91.6 ± 9.3 vs. PL: 88.8 ± 8.2 mmHg, p < 0.05) were higher with BR supplementation.

Conclusion: These findings suggest that the acute intake of BR juice had no effect on knee extensor muscle strength or fatigue but increased BP in a healthy recreationally active population.

Purpose: In the present pilot study, we aimed to investigate the effects of the Silverrobics exercise program, which is similar to aerobic dance, on the factors related to glucose metabolism and liver enzymes.

Methods: Eight elderly women with obesity and impaired fasting glucose participated in the Silverrobics exercise program (60 minutes per session for five times a week for 8 weeks). The program was conducted at 50-60% of the heart rate reserve at 1 to 2 weeks and at 60-80% of the heart rate reserve at 3 to 8 weeks. To verify the effect of this 8-week exercise program on glucose metabolism and liver enzymes, blood analysis at pre- and post-training was performed.

Results: After the Silverrobics exercise program, there were significant decreases in the glucose (p<0.05), glycated hemoglobin A1c (p<0.05), 1,5-anhydroglucitol (p<0.05), and insulin levels (p<0.01) and homeostatic model assessment of insulin resistance score (p<0.05). However, there were no significant effects on the liver enzymes, except for alkaline phosphatase. The alkaline phosphatase level increased after the Silverrobics exercise program (p<0.05).

Conclusion: Although the Silverrobics exercise program had no beneficial effects on the liver enzymes, it may play an important role in preventing liver diseases considering the effects on glucose metabolism.

Purpose: The purpose of this study was to investigate the effects of treadmill exercise on oxidative stress in the hippocampal tissue and mitochondrial dynamic-related proteins in rats fed a long-term high-fat diet (HFD).

Methods: Obesity was induced in experimental animals using high fat feed, and the experimental groups were divided into a normal diet-control (ND-CON; n=12), a high fat diet-control (HFD-CON; n=12) and a high fat diet-treadmill exercise (HFD-TE; n=12) group. The rats were subsequently subjected to treadmill exercise (progressively increasing load intensity) for 8 weeks (5 min at 8 m/min, then 5 min at 11 m/min, and finally 20 min at 14 m/min). We assessed weight, triglyceride (TG) concentration, total cholesterol (TC), area under the curve, homeostatic model assessment of insulin resistance, and AVF/body weight. Western blotting was used to examine expression of proteins related to oxidative stress and mitochondrial dynamics, and immunohistochemistry was performed to examine the immunoreactivity of gp91phox.

Results: Treadmill exercise effectively improved the oxidative stress in the hippocampal tissue, expression of mitochondrial dynamic-related proteins, and activation of NADPH oxidase (gp91phox) and induced weight, blood profile, and abdominal fat loss.

Conclusion: Twenty weeks of high fat diet induced obesity, which was shown to inhibit normal mitochondria fusion and fission functions in hippocampal tissues. However, treadmill exercise was shown to have positive effects on these pathophysiological phenomena. Therefore, treadmill exercise should be considered during prevention and treatment of obesity-induced metabolic diseases.

Purpose: The combined effect of different types of post-exercise treatment has not been fully explored. We investigated the effect of combined cold water immersion (CWI) and compression garment (CG) use after maximal eccentric exercise on maximal muscle strength, indirect muscle damage markers in the blood, muscle thickness, and muscle soreness score 24 h after exercise.

Methods: Ten men performed two trials (CWI + CG and CON) in random order. In the CWI + CG trial, the subjects performed 15 min of CWI (15°C), followed by wearing of a lower-body CG for 24 h after exercise. In the CON trial, there was no post-exercise treatment. The exercise consisted of 6 × 10 maximal isokinetic (60°·s-1) eccentric knee extensions using one lower limb. The maximal voluntary contraction (MVC) and maximal isokinetic (60°·s-1) strength during knee extension, as well as the indirect muscle damage markers, were evaluated before exercise and 24 h after exercise.

Results: The maximal muscle strength decreased in both trials (p < 0.001), with no difference between them. The exercise-induced elevation in the myoglobin concentration tended to be lower in the CWI + CG trial than in the CON trial (p = 0.060). The difference in the MVC, maximal isokinetic strength, muscle thickness, and muscle soreness score between the trials was not significant.

Conclusion: CWI followed by wearing of a CG after maximal eccentric exercise tended to attenuate the exercise-induced elevation of indirect muscle damage markers in the blood.

Purpose: To date, there have been no studies on the response of wrist tremor to increased muscle activity during exercise. This study aimed to evaluate the wrist tremor response with increasing muscle activity during bench press exercise.

Methods: Triceps muscle activity and wrist tremor response were measured by electromyography and an accelerometer, respectively, during bench press exercise in 11 healthy men without weight-training experience. Subjects performed bench press at 30% repetition maximum (RM), and the rating of perceived exertion (RPE) and lactate concentration were measured before and after exercise. One week later, an equivalent number of bench presses at 30% RM was performed without weight load as a control trial (CT).

Results: RPEs and lactate concentrations significantly increased after resistance exercise (30% RM) from 7.4 to 14.3 and 1.7 to 4.9, respectively (P<.01), but no such difference was observed in the CT. Muscle activity linearly increased during the 30% RM exercise, and wrist tremors were shown to linearly decrease. A strong negative correlation was observed between the two variables (r=-0.88, P<.001).

Conclusion: We found that wrist tremors during resistance exercise, as measured using an accelerometer, can be used to predict muscle activity.

Purpose: The purpose of the study was to determine the combined effects of resveratrol supplementation with high-flow LSS on mitochondrial biogenesis in human vascular endothelial cells.

Methods: Cultured human umbilical vein endothelial cells were treated with 20 μM of RSV. For the shear experiments, cells grown to a >90% confluence were exposed to physiological levels of LSS (5 to 20 dyne/cm2) for 12 to 36 hours using a cone and plate shear apparatus. Gene expressions were analyzed by western blotting.

Results: Depletion of mitochondrial integrity was directly associated with increase in endothelial activation/dysfunction. The expressions of mitochondrial biogenesis regulator genes, such as SIRT1, PGC-1α, and TFAM, and the mitochondrial contents were significantly increased after treatment with both resveratrol and high-flow LSS for 12 hours. However, supplementation of resveratrol to high-flow LSS for a prolonged duration had no synergistic effect on the levels of mitochondrial biogenesis regulator gene expressions and mitochondrial content compared to the LSS treatment alone.

Conclusion: The present study demonstrated that the supplementation of resveratrol to high-flow LSS has no synergistic effects on enhancing mitochondrial integrity in human vascular endothelial cells.

Purpose: The OPG/RANK/RANKL signaling is a new family of bone metabolism biomarkers belonging to the immune system. However, the bone metabolism response to long-term exercise in the RANKL/RANK/OPG signaling is less evident. The purpose of this study was to examine these biomarkers in healthy college females after 12-weeks combined exercise intervention.

Methods: Participants (N=22, 22.4±1.3yrs) were randomly divided in two different group: 12 in the control group and 10 in the exercise group performing combined exercise program that interventions was conducted 3 times per week for 12 weeks. The outcome measures included serum concentrations of RANKL, OPG and bone metabolic cytokines such as TNF-α and IL-6, and mRNA expressions of same variables from PBMC. VO2max and bone mineral density (BMD) were measured at before and after exercise intervention.

Results: There were no significant differences in the serum RANKL, OPG concentrations and all RANKL/RANK/OPG signaling mRNA expression on interaction effect between group and time (NS). Also no significant differences were found in the serum TNF-α and IL-6 concentrations and mRNA expression (NS). The IL-6 mRNA expression only showed significant difference in the main effect of groups (p<.05). There were also no significant differences in the VO2max and BMD on interaction effect between group and time (NS).

Conclusion: These results suggested that there were no effects on bone mineral density and RANKL/RANK/OPG signaling without the effect of 8-weeks combined exercise on cardiovascular endurance fitness.

Purpose: This study examined the association of hand-grip strength (HGS) and non-alcoholic fatty liver disease (NAFLD) index in older adults.

Methods: This was a cross-sectional study involving 538 older adults with mean age of 74.3±6.4 years. Body composition parameters including height, percent body fat, body mass index (BMI), waist circumference (WC), was determined using body composition analyzer. HGS was assessed using a dynamometer, and NAFLD was diagnosed by the simple NAFLD score (SNS), hepatic steatosis index (HSI), NAFLD fibrosis score (NFS), and fibrosis 4 calculator (FIB-4). Based on relative HGS, subjects were classified as High HGS, Mid HGS, and Low HGS group. Based on SNS, HSI, NFS and FIB-4 score, subjects were classified as High risk and Low risk group. Logistic regression analyses were used to determine the odds ratio (OR) and 95% confidence interval (CI) of HGS levels for having steatosis and fibrosis.

Results: There were linear decreases in NAFLD index such as SNS (P<.001), HSI (P<.001), NFS (P=.001), and FIB-4 (P=.041) across incremental HGS levels. Compared to the High HGS group (reference), the Low HGS group had significantly higher ORs of having SNS (OR=4.583, 95% CI=2.608-8.054, P<.001), HSI (OR=11.697, 95% CI=5.261-26.005, P<.001), and NFS (OR=1.709, 95% CI=1.005-2.907, P=.048).

Conclusion: The current findings suggest that a lifestyle intervention consisting of a normal weight and physical fitness should be promoted as a preventive means against NAFLD associated with HGS.