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Modulation of Countermovement Jump-Derived Markers of Neuromuscular Function With Concurrent vs. Single-Mode Resistance Training.
Pattison, KJ, Drinkwater, EJ, Bishop, DJ, Stepto, NK, Fyfe, JJ
Journal of strength and conditioning research. 2020;(6):1497-1502
Abstract
Pattison, KJ, Drinkwater, EJ, Bishop, DJ, Stepto, NK, and Fyfe, JJ. Modulation of countermovement jump-derived markers of neuromuscular function with concurrent vs. single-mode resistance training. J Strength Cond Res 34(6): 1497-1502, 2020-This study assessed changes in countermovement jump (CMJ)-derived markers of neuromuscular function with concurrent training vs. resistance training (RT) alone and determined associations between changes in CMJ parameters and other neuromuscular adaptations (e.g., maximal strength gain). Twenty-three recreationally active men performed 8 weeks of RT alone (RT group, n = 8) or combined with either high-intensity interval training cycling (HIIT + RT group, n = 8) or moderate-intensity continuous cycling (MICT + RT group, n = 7). Maximal strength and CMJ performance were assessed before (PRE), after 4 weeks of training (MID), and >72 hours (maximal strength) or >5-7 days (CMJ performance) after (POST) the training intervention. Improvements in CMJ relative peak force from both PRE to MID and PRE to POST were attenuated for both HIIT + RT (effect size [ES]: -0.44; ±90% confidence limit, ±0.51 and ES: -0.72; ±0.61, respectively) and MICT + RT (ES: -0.74; ±0.49 and ES: -1.25; ±0.63, respectively). Compared with RT alone, the change in the flight time to contraction time ratio (FT:CT) was attenuated from PRE to MID for MICT + RT (ES: -0.38; ±0.42) and from PRE to POST for both MICT + RT (ES: -0.60; ±0.55) and HIIT + RT (ES: -0.75; ±0.30). PRE to POST changes in both CMJ relative peak force and flight time:contraction time (F:C) ratio were also associated with relative 1 repetition maximum leg press strength gain (r = 0.26 and 0.19, respectively). These findings highlight the utility of CMJ testing for monitoring interference to improvements in neuromuscular function with concurrent training.
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Hypertension is associated with blunted NO-mediated leg vasodilator responsiveness that is reversed by high-intensity training in postmenopausal women.
Gunnarsson, TP, Ehlers, TS, Baasch-Skytte, T, Lund, AP, Tamariz-Ellemann, A, Gliemann, L, Nyberg, M, Bangsbo, J
American journal of physiology. Regulatory, integrative and comparative physiology. 2020;(6):R712-R723
Abstract
The menopausal transition is associated with increased prevalence of hypertension, and in time, postmenopausal women (PMW) will exhibit a cardiovascular disease risk score similar to male counterparts. Hypertension is associated with vascular dysfunction, but whether hypertensive (HYP) PMW have blunted nitric oxide (NO)-mediated leg vasodilator responsiveness and whether this is reversible by high-intensity training (HIT) is unknown. To address these questions, we examined the leg vascular conductance (LVC) in response to femoral infusion of acetylcholine (ACh) and sodium nitroprusside (SNP) and skeletal muscle markers of oxidative stress and NO bioavailability before and after HIT in PMW [12.9 ± 6.0 (means ± SD) years since last menstrual cycle]. We hypothesized that ACh- and SNP-induced LVC responsiveness was reduced in hypertensive compared with normotensive (NORM) PMW and that 10 wk of HIT would reverse the blunted LVC response and decrease blood pressure (BP). Nine hypertensive (HYP (clinical systolic/diastolic BP, 149 ± 11/91 ± 83 mmHg) and eight normotensive (NORM (122 ± 13/75 ± 8 mmHg) PMW completed 10 wk of biweekly small-sided floorball training (4-5 × 3-5 min interspersed by 1-3-min rest periods). Before training, the SNP-induced change in LVC was lower (P < 0.05) in HYP compared with in NORM. With training, the ACh- and SNP-induced change in LVC at maximal infusion rates, i.e., 100 and 6 µg·min-1·kg leg mass-1, respectively, improved (P < 0.05) in HYP only. Furthermore, training decreased (P < 0.05) clinical systolic/diastolic BP (-15 ± 11/-9 ± 7 mmHg) in HYP and systolic BP (-10 ± 9 mmHg) in NORM. Thus, the SNP-mediated LVC responsiveness was blunted in HYP PMW and reversed by a period of HIT that was associated with a marked decrease in clinical BP.
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Genetic polymorphisms in the FVII gene is associated with lower extremity deep venous thrombosis: A case-control study.
Liu, JW, Chen, DQ
Journal of cellular biochemistry. 2018;(8):6715-6722
Abstract
This study aims to explore the associations between FVII gene polymorphisms (R353Q, 5'F7, and -402G/A) and lower extremity deep venous thrombosis (LEDVT) in a Chinese Han population. LEDVT patients (153) and healthy people (174) were, respectively, as case and control groups and evaluated related biochemical indicators. Gene polymorphisms of R353Q, 5'F7, and -402G/A of FVII, serum FVII level, antithrombin activity, plasma fibrinogen content, and plasma D-dimer (D-D) level were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), ELISA, chromogenic substrate assay, coagulating assay, and Immunoturbidimetry assay, respectively. Compared with the control group, the case group had a higher level of body mass index (BMI), glucose, and fibrinogen, and lower level of total cholesterol (TC). Notable differences were found in GG genotype, G and A alleles, as well as distribution of recessive model of -402G/A. The serum FVII level of GG genotype was higher than that of GA and AA genotypes. FIB and D-D had a higher level had a lower level in GG genotype when compared with GA and AA genotypes. Smoking, drinking, serum FVII level, and -402G/A-GG were the independent risk factors for LEDVT. This study demonstrates that -402G/A of FVII may be a risk factor for LEDVT patients in a Chinese Han population.
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Diabetic polyneuropathy is a risk factor for decline of lower extremity strength in patients with type 2 diabetes.
Nomura, T, Ishiguro, T, Ohira, M, Ikeda, Y
Journal of diabetes investigation. 2018;(1):186-192
Abstract
AIMS/INTRODUCTION The present study elucidated the effect of diabetic polyneuropathy (DPN) on lower extremity strength in a wide age range of type 2 diabetes patients. MATERIALS AND METHODS Participants (n = 1,442) were divided into three age groups (30-49 years, 50-69 years and 70-87 years), and comparisons were made separately for each sex. Lower extremity strength was measured in terms of knee extension force (KEF) with a hand-held dynamometer. KEF was compared according to the presence or absence of DPN. Furthermore, the effect of DPN on KEF with other diabetic complications (diabetic retinopathy and diabetic nephropathy), diabetes status (diabetes duration and glycated hemoglobin) and habitual behavior (regular exercise, smoking and drinking behaviors) as explanatory variables was analyzed using multiple regression analysis in several models. RESULTS The frequency of DPN differed among age groups, ranging from 14.3 to 49.6%, and increasing with age. There was no significant difference in KEF between patients aged 30-49 years with and without DPN. However, among both men and women aged 50-69 years and 70-87 years, patients with DPN showed significantly diminished KEF (11.0-12.9% and 11.9-16.6%, respectively) compared with those without DPN (P < 0.01-0.001). In women aged 50-69 years and 70-87 years, and in men aged 50-69 years, DPN was a significant explanatory variable for KEF in all multiple regression analysis models. CONCLUSION DPN might reinforce a KEF decline in middle-aged and elderly type 2 diabetes patients.
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The LargPAD Trial: Phase IIA evaluation of l-arginine infusion in patients with peripheral arterial disease.
Kashyap, VS, Lakin, RO, Campos, P, Allemang, M, Kim, A, Sarac, TP, Hausladen, A, Stamler, JS
Journal of vascular surgery. 2017;(1):187-194
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Abstract
OBJECTIVE Endothelial function is improved by l-arginine (l-arg) supplementation in preclinical and clinical studies of mildly diseased vasculature; however, endothelial function and responsiveness to l-arg in severely diseased arteries is not known. Our objective was to evaluate the acute effects of catheter-directed l-arg delivery in patients with chronic lower extremity ischemia secondary to peripheral arterial disease. METHODS The study enrolled 22 patients (45% male) with peripheral arterial disease (mean age, 62 years) requiring lower extremity angiography. Endothelium-dependent relaxation of patent but atherosclerotic superficial femoral arteries was measured using a combination of intravascular ultrasound (IVUS) imaging and a Doppler FloWire (Volcano Corporation, Rancho Cordova, Calif) during the infusion of incremental acetylcholine (10-6 to 10-4 molar concentration) doses. Patients received 50 mg (n = 3), 100 mg (n = 10), or 500 mg (n = 9) l-arg intra-arterially, followed by repeat endothelium-dependent relaxation measurement (limb volumetric flow). IVUS-derived virtual histology of the culprit vessel was also obtained. Endothelium-independent relaxation was measured using a nitroglycerin infusion. Levels of nitrogen oxides and arginine metabolites were measured by chemiluminescence and mass spectrometry, respectively. RESULTS Patients tolerated limb l-arg infusion well. Serum arginine and ornithine levels increased by 43.6% ± 13.0% and 23.2% ± 10.3%, respectively (P < .005), and serum nitrogen oxides increased by 85% (P < .0001) after l-arg infusion. Average vessel area increased by 6.8% ± 1.3% with l-arg infusion (acetylcholine 10-4; P < .0001). Limb volumetric flow increased in all patients and was greater with l-arg supplementation by 130.9 ± 17.6, 136.9 ± 18.6, and 172.1 ± 24.8 mL/min, respectively, for each cohort. Maximal effects were seen with l-arg at 100 mg (32.8%). Arterial smooth muscle responsiveness to nitroglycerin was intact in all vessels (endothelium-independent relaxation, 137% ± 28% volume flow increase). IVUS-derived virtual histology indicated plaque volume was 14 ± 1.3 mm3/cm, and plaque stratification revealed a predominantly fibrous morphology (46.4%; necrotic core, 28.4%; calcium, 17.4%; fibrolipid, 6.6%). Plaque morphology did not correlate with l-arg responsiveness. CONCLUSIONS Despite extensive atherosclerosis, endothelial function in diseased lower extremity human arteries can be enhanced by l-arg infusion secondary to increased nitric oxide bioactivity. Further studies of l-arg as a therapeutic modality in patients with endothelial dysfunction (ie, acute limb ischemia) are warranted.