We examined the effects of high-intensity resistance training (HIT) and low-intensity blood flow-restricted (LI-BFR) resistance training on carotid arterial compliance. Nineteen young men were randomly divided into HIT (n = 9) or LI-BFR (n = 10) groups. The HIT and LI-BFR groups performed 75 and 30 %, respectively, of one-repetition maximum (1-RM) bench press exercise, 3 days per week for 6 weeks. During the training sessions, the LI-BFR group wore elastic cuffs around the most proximal region of both arms. Muscle cross-sectional area (CSA), 1-RM strength, and carotid arterial compliance were measured before and 3 days after the final training session. Acute changes in systolic arterial pressure (SAP), plasma endothelin-1 (ET-1), nitrite/nitrate (NOx), and noradrenalin concentrations were also measured during and after a bout of training session. The training led to significant increases (P < 0.01) in bench press 1-RM and arm and chest muscle CSA in the two training groups. Carotid arterial compliance decreased significantly (P < 0.05) in the HIT group, but not in the LI-BFR group. There was a significant correlation (r = -0.533, P < 0.05) between the change in carotid arterial compliance and the acute change in SAP during training sessions; however, ET-1 and NOx did not correlate with carotid arterial compliance. Our results suggest that muscle CSA and strength increased following 6 weeks of both HIT and LI-BFR training. However, carotid arterial compliance decreased in only the HIT group, and the changes were correlated with SAP elevations during exercise sessions.
These results suggest that LRE acutely increases arterial compliance and decreases arterial stiffness.
Homozygosity for the common nonsense polymorphism R577X in the α-actinin-3 gene (ACTN3) causes complete α-actinin-3 deficiency in fast-twitch skeletal muscle fibers. This study investigated whether the ACTN3 R577X polymorphism affects fitness status using a battery of tests in a large Japanese cohort. In the present study, 1227 subjects (age: 25-85 years) were genotyped for the ACTN3 R577X polymorphism (rs1815739) using a TaqMan SNP genotyping assay (Applied Biosystems). All subjects were divided into 2 groups based on their age (<55 years and ≥55 years). All subjects completed a questionnaire about exercise habits and were subjected to a battery of tests to assess their fitness status (including grip strength test, chair stand test, and 8-foot walking test). A significant association between the ACTN3 R577X genotype and chair stand test performance was observed in the group of men ≥55 using ANCOVA adjusted for age and exercise habits (p = 0.036). The ACTN3 R577X genotype accounted for 2.5% of the variability in the results of the chair stand test among men in the ≥55 age group. Moreover, for the ≥55 age group, performance in the chair stand test was lower among those with the XX genotype than among those with the RR genotype (p = 0.024) or RX genotype (p = 0.005), unlike results for the <55 age group. No significant difference was noted for hand grip strength or 8-foot walking time. Thus, our results suggest that the ACTN3 R577X genotype is associated with lower-extremity muscle function in the Japanese population.
The purpose of this study was to compare the peak oxygen uptake (VO2peak) and lactate threshold / onset of blood lactate accumulation (LT/OBLA) during an incremental exercise test with and without blood flow restriction (BFR). Six male subjects performed a graded walking test on a treadmill with and without BFR in random order, and oxygen uptake (VO2), minute ventilation (VE), and blood lactate concentration were measured during each test. During the BFR test, the subjects wore pressure cuff belts on the most proximal portion of each thigh. At a given workload (e.g. during walking at 100 m/min) VO2 was 17% higher in BFR than in free-flow. Exercise time to exhaustion during BFR was shorter compared with free-flow despite the ratings of perceived exertion being similar between both conditions. Peak heart rate did not reach same level in the BFR test as it did in free-flow, with the heart rate 5 beats lower with BFR. VO2peak and VE peak were also 17% and 9%, respectively, lower in BFR than in free-flow. Compared with the control, O2 pulse (an index of stroke volume) was 14% lower in BFR. During BFR, VO2 at LT and OBLA were lower compared with free-flow. However, percentages of VO2peak at LT and OBLA were similar between BFR and free-flow. Our results suggest that the BFR-induced decrease in VO2peak may be associated with reductions in venous return and stroke volume. Additionally, these results suggest that increased muscle fiber recruitment with BFR may relate to the earlier LT/OBLA observed at lower intensities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.