Background
Resistance training with blood flow restriction (BFR) is a physiological ischaemic training method. Before it is applied to patients with coronary artery disease, it must be proven safe and effective.
Methods
Twenty-four healthy adult males were randomly assigned to three groups: the resistance training (RT) group, low-pressure BFR and resistance training (LP-RT) group and high-pressure BFR and resistance training (HP-RT) group. The training protocol was 20 times/min/set, with a 2-min break, five sets/day and 5 d/week for 8 weeks. Cardiac function, haemodynamics and vascular endothelial function were evaluated before and after the first training and the last training.
Results
There were no significant differences among groups before and after training. After 8 weeks of training, the resting heart rate (p<0.05) of the three groups significantly decreased (p<0.05). The rate–pressure product in the LP-RT group significantly decreased (p<0.05) compared with before training. Just after the last training, heart rate (p<0.05) and cardiac output (p<0.05) in the LP-RT and HP-RT groups significantly decreased compared with those just after the first training. At the end of the experiment, vascular endothelial growth factor (VEGF; p<0.01), soluble VEGF receptor (VEGFR) (p<0.05) and interleukin-6 (p<0.01) significantly increased, except for soluble VEGFR in the RT group.
Conclusions
Low-intensity resistance training with BFR moderately alters cardiac function. The expression levels of proteins related to vascular endothelial function have significantly changed. Both findings suggest that low-intensity resistance training with BFR may be safely and effectively applied to patients with coronary artery disease.
Physiologic ischemic training of skeletal muscle may induce collateral circulation development in the myocardium, thus decreasing infarct size when infarction occurs.
An animal model of Osteoarthritis (OA) was established to observe the influences of low-intensity pulsed ultrasound (LIPUS) and nano magnet application (NMA) on Collagenase 3 (MMP-13) expression and the activation status of mitogen activated protein kinases (MAPKs) in rabbit. 24 experimental rabbits from New Zealand were randomly divided into four groups: LIPUS, NMA, LIPUS + NMA group, and control group. The experimental rabbit OA model was established in the right knee joint of rabbits received ACLT operation. Rabbits in LIPUS group received LIPUS treatment and rabbits in NMA group were given NMA treatment. In LIPUS + NMA group, both treatments were applied on experimental rabbits everyday. However, the rabbits in control group only underwent ACLT operation. Four weeks later all rabbits were killed and changes of histopathology in rabbit articular cartilage were assessed and evaluated using Mankin method (Modified Mankin Scale). The protein expressions of MMP-13 and MAPKs were estimated using Western Blot. The results showed that both LIPUS and NMA treatments could significantly decrease the Mankin scores and suppress the expression level of MMP-13. However, there were some inverse results of MAPKs expression in these two applications and imply their treatment mechanisms of OA were different from each other.
Objective
The aim of this study was to investigate the effects of physiologic ischemia training (PIT) on the proliferation of endothelial progenitor cells (EPCs) and the corresponding changes in the influencing factors in atherosclerotic rabbits, including vascular endothelial growth factor (VEGF) and nitric oxide (NO).
Materials and methods
Eighteen rabbits were assigned randomly to three groups: a high-fat diet (HD) group, an HD-with-training (HT) group, and a control group. Rabbits in the HD and HT groups were fed high-fat food and those in the HT group were administered PIT from the seventh week onward. Atherosclerotic plaques in the thoracic aorta were stained with Oil Red O and measured by Image-Pro Plus 6.0; VEGF expression was measured using an enzyme-linked immunosorbent assay and real-time PCR to determine both protein and mRNA levels. EPCs were counted using a fluorescence-activated cell sorter; NO in plasma was measured by the Griess reaction; and the levels of blood lipids were measured using a biochemical analyzer.
Results
More lipid-containing lesions were found in the HD group than in the HT group (
P
<0.01), whereas atherosclerotic plaques were not observed in the control group. In addition, the expression of VEGF, production of NO, and levels of blood lipids were consistent with the proportion of plaques. It is noteworthy that the proliferation of EPCs increased in the HT group throughout the 10 weeks, whereas those in the control and HD groups increased in the first 6 weeks and declined during the 10th week (
P
<0.01).
Conclusion
PIT may prevent the development of aortic atherosclerosis by promoting the proliferation of EPCs in atherosclerotic rabbits.
Background: The effect of resistance exercise on the autonomic nervous system of patients with hypertension has not been identified.Objective: To explore a suitable resistance training method for hypertension patients to regulate blood pressure (BP) and autonomic nervous system function.Method: Forty-five hypertension patients aged between 55 and 70 years were randomly equally divided into three groups: the high-intensity resistance exercise (HE) group, the low-intensity resistance exercise combined with blood flow restriction (LE-BFR) group, and the low-intensity resistance exercise (LE) group. All patients performed quadriceps femoris resistance exercise. The exercise intensity of HE, LE-BFR and LE group was 65, 30 and 30% of one repetition maximum (1RM), respectively. The LE-BFR group used pressure cuffs to provide 130% of systolic pressure to the patient’s thighs during resistance exercise. The training program was 20 times/min/set with a 1-min break after each set, and was conducted five sets/day and 3 days/week, lasting for 12 weeks. The heart rate (HR), BP, root-mean-square of difference-value of adjacent RR intervals (RMSSD), low frequency (LF) and high frequency (HF) were evaluated before and after the first training and the last training.Result: Significant differences in HR were observed in both recovery states after the first and last training (p < 0.01). After 12 weeks of training, the recovery speed of HR in the LE-BFR group increased significantly (p < 0.01). The systolic blood pressures in the HE and LE-BFR group were significantly reduced (p < 0.05 and p < 0.01), and the differences among groups were significant (p < 0.01). In the last recovery state, the RMSSD of the LE group was significantly lower than that in the first recovery state (p < 0.01). The LF/HF ratios of the HE and LE groups in the resting and recovery states were increased significantly (all p < 0.01). LF/HF ratios in the LE-BFR group in the resting and recovery state were decreased significantly (both p < 0.01).Conclusion: Compared to HE and LE, LE-BFR could effectively decrease systolic pressure and regulate the autonomic nervous system function in hypertension patients.
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