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Acute Cardiovascular Response during Resistance Exercise with Whole-body Vibration in Sedentary Subjects: A Randomized Cross-over Trial.
Dias, T, Polito, M
Research in sports medicine (Print). 2015;(3):253-64
Abstract
This study aimed to compare the acute cardiovascular responses during and after resistance exercise with and without whole-body vibration. Nineteen sedentary adults randomly performed one session of isometric squats without vibration and the same exercise with vibration. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were measured. SBP, DBP and HR were also measured for 20 min after the sessions. The exercise with vibration demonstrated significant values (P < 0.05) for SBP (second to sixth sets), DBP (third to sixth sets) and SVR (second to sixth sets) compared with the exercise without vibration. After the sessions, the values of SBP for both exercises were significantly lower than the respective resting values; with no difference between the sessions. In conclusion, exercise with vibration caused increases in SBP, DBP and SVR compared with exercise with no vibration in sedentary adults.
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2.
Effects of muscle pain induced by glutamate injections during sustained clenching on the contraction pattern of masticatory muscles.
Michelotti, A, Cioffi, I, Rongo, R, Borrelli, R, Chiodini, P, Svensson, P
Journal of oral & facial pain and headache. 2014;(3):252-60
Abstract
AIMS: To evaluate the contraction pattern of masticatory muscles during sustained clenching tasks with or without experimental pain induced by glutamate injection into the masseter muscle. It was hypothesized that acute muscle pain could induce compensatory changes in the electromyographic (EMG) activity of the masticatory muscles. METHODS Fifteen volunteers (seven males, mean age ± SD = 29.7 ± 1.1 years; eight females, mean age ± SD = 23.5 ± 1.2 years) were recruited in a crossover experimental study. All subjects participated in two randomized 20-minute experimental sessions. Each subject was asked to clench at 25% of the maximum voluntary contraction (MVC). After 10 minutes, isotonic saline or glutamate was injected in random order into the right masseter. EMG activity (root mean square [RMS] and mean power frequency [MPF]) was assessed in the masseter and anterior temporalis muscles on both sides. Pain and fatigue were assessed by 0-10 numeric rating scales (NRS) every minute. Differences between conditions (isotonic saline vs glutamate) for all the outcome parameters were analyzed by using a mixed effect model. RESULTS The EMG activity of the masticatory muscles and pain and fatigue scores were not dependent on isotonic saline/glutamate injection (all P > .05). The RMS in the temporalis and masseter muscles increased with time (right masseter P = 0.001, left masseter P = .004, right temporalis P = .22, left temporalis P = .006), whereas the MPF decreased (right masseter P = .0001, left masseter P < .0001, right temporalis P = .51, left temporalis P = .0005). Scores for fatigue and pain increased during the experimental sessions (all P < .05). CONCLUSION Intramuscular injection of glutamate caused more pain than isotonic saline but did not affect the contraction pattern of the masticatory muscles during a sustained clenching task. This finding strongly suggests the adaptive capacity of the stomatognathic system in the presence of acute nociceptive inputs.
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3.
Skeletal muscle molecular responses to resistance training and dietary supplementation in COPD.
Constantin, D, Menon, MK, Houchen-Wolloff, L, Morgan, MD, Singh, SJ, Greenhaff, P, Steiner, MC
Thorax. 2013;(7):625-33
Abstract
BACKGROUND Skeletal muscle dysfunction is a systemic feature of chronic obstructive pulmonary disease (COPD), contributing to morbidity and mortality. Physical training improves muscle mass and function in COPD, but the molecular regulation therein is poorly understood. METHODS Candidate genes and proteins regulating muscle protein breakdown (ubiquitin proteasome pathway), muscle protein synthesis (phosphatidylinositol 3 kinase/Akt/mammalian target of rapamycin pathway), myogenesis (MyoD, myogenin and myostatin) and transcription (FOXO1, FOXO3 and RUNX1) were determined in quadriceps muscle samples taken at four time points over 8 weeks of knee extensor resistance training (RT) in patients with COPD and healthy controls (HCs). Patients with COPD were randomly allocated to receive protein/carbohydrate or placebo supplements during RT. RESULTS 59 patients with COPD (mean (SD) age 68.0 (9.3) years, forced expiratory volume in 1 s (FEV1) 46.9 (17.8) % predicted) and 21 HCs (66.1 (4.8) years, 105.0 (21.6) % predicted) were enrolled. RT increased lean mass (~5%) and strength (~20%) in all groups. Absolute work done during RT was lower throughout in patients with COPD compared with HCs. RT resulted in increases (from basal) in catabolic, anabolic, myogenic and transcription factor protein expression at 24 h, 4 weeks and 8 weeks of exercise in HCs. This response was blunted in patients with COPD, except for myogenic signalling, which was similar. Nutritional supplementation did not augment functional or molecular responses to RT. CONCLUSIONS The potential for muscle rehabilitation in response to RT is preserved in COPD. Except for markers of myogenesis, molecular responses to RT are not tightly coupled to lean mass gains but reflect the lower work done during RT, suggesting some caution when identifying molecular targets for intervention. Increasing post-exercise protein and carbohydrate intake is not a prerequisite for a normal training response in COPD.
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4.
Changes in metabolic and muscle damage indicators following a single bout of jump training on stair versus at level.
Váczi, M, Tékus, E, Kaj, M, Kőszegi, T, Ambrus, M, Tollár, J, Atlasz, T, Szabadfi, K, Karsai, I
Acta physiologica Hungarica. 2013;(4):445-56
Abstract
UNLABELLED We hypothesized that stair-jump exercise would induce less muscle damage and greater acute metabolic responses than level-jumps. METHODS Trained males executed 100 unilateral jumps on stairs with one leg, and at level with the other leg, with two weeks hiatus. Maximal isometric voluntary torque (MVC) and rate of torque development (RTD)in the quadriceps, and unilateral vertical jump height (VJ) were determined in the trained leg at pre-exercise,immediately at post- (IP), 24 h and 48 h after exercise. Serum creatine kinase (CK) level and delayed onset muscle soreness (DOMS) were evaluated at pre-exercise, 24 h and 48 h. Acute lactate and heart rate responses were also measured. RESULTS Lactate and heart rate at IP increased similarly under the two conditions. CK was elevated and MVC was depressed while RTD and VJ remained unchanged at 24 h in both types of training. MVC recovered at 48 h only after stair-jump exercise. DOMS developed only after level-jumps. Except DOMS, no effects of condition were found in any other variables. CONCLUSIONS We conclude that vigorous stair-jump exercise highly stresses the aerobic and the anaerobic energy system, and it preserves power and rapid torque generating ability 24 h after exercise. Stair-jump could be one alternative exercise to prevent muscle soreness.
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5.
Analysis of various conditions in order to measure electromyography of isometric contractions in water and on air.
Carvalho, RG, Amorim, CF, Perácio, LH, Coelho, HF, Vieira, AC, Karl Menzel, HJ, Szmuchrowski, LA
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2010;(5):988-93
Abstract
The aim of this study was to verify if there are differences in the amplitude of signals from surface electromyography (EMG) during maximal and submaximal voluntary isometric contraction (MVC and 50% MVC, respectively) under different conditions, in our case, water and air, with and without extra protection (water-resistant tape) on the electrode. The isometric force and muscle activation of the MVC and 50% MVC of the biceps brachial muscle of nine healthy trained men were measured simultaneously, performed in water and on air, with and without protection of the EMG electrode. The multivariate analysis of variance with a post hoc Tukey test was applied to detect significant differences between the levels of muscular force. For the amplitude values of the EMG signal, the Wilcoxon signed rank test was applied to compare all experimental conditions in order to detect a significance of p<0.05. The values of isometric force were not significantly different among conditions (MVC and 50% MVC). The results showed a significant difference among conditions in the water without extra protection compared to the conditions on air with and without extra protection and in water with extra protection. Reduced EMG amplitude was seen in water without extra protection from 37.04% to 55.81% regarding the other conditions. However, no significant difference was seen among conditions in water with extra protection in relation the conditions on air (with and without extra protection). This study suggest that it is necessary to use a water-resistant tape as an extra protection on the electrode when using EMG underwater, to avoid having a significant decrease in the EMG amplitude underwater and not to suffer interference from the water. There was no significant difference among the recordings of EMG with and without the use of protection on air; therefore, the protection does not influence the recording of EMG amplitude and isometric force on air.
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6.
Electromyographic assessment of the activity of the masticatory using the agonist contract-antagonist relax technique (AC) and contract-relax technique (CR).
Olivo, SA, Magee, DJ
Manual therapy. 2006;(2):136-45
Abstract
Proprioceptive neuromuscular facilitation (PNF) techniques are a group of therapeutic procedures that may be used to cause relaxation of muscles. Studies have found controversial results when applying these techniques. The aim of the present study was to evaluate the effectiveness of masticatory muscle relaxation through the use of the contract-relax technique (CR) when compared with the agonist contract-antagonist relax technique (AC). A convenience sample of 30 students was recruited for this study. The CR and the AC techniques were applied to the subjects in order to cause relaxation of the masticatory muscles. Electromyography activity of all muscles was registered. Two way ANOVA with repeated measures analysis demonstrated that both the AC technique and the CR technique did not decrease the EMG activity of masticatory muscles (P>0.05). Instead, both techniques caused an increase in electromyographic activity of the masticatory muscles. Based on the results obtained from this study, both the CR and the AC techniques were not effective in causing relaxation of the masticatory muscles. The purported physiological mechanisms of PNF techniques, which stated that they act through reciprocal inhibition and autogenic inhibition causing muscular relaxation, are not supported by this study.
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7.
Delayed reoxygenation after maximal isometric handgrip exercise in high oxidative capacity muscle.
Kime, R, Hamaoka, T, Sako, T, Murakami, M, Homma, T, Katsumura, T, Chance, B
European journal of applied physiology. 2003;(1):34-41
Abstract
We hypothesized that after maximal short-term isometric exercise, when O(2) demand is still high and O(2) supply is not fully activated, higher oxidative capacity muscle may exhibit slower muscle reoxygenation after the exercise than low oxidative capacity muscle. Seven healthy male subjects performed a maximal voluntary isometric handgrip exercise for 10 s. The reoxygenation rate after the exercise (Reoxy-rate) in the finger flexor muscle was determined by near infrared continuous wave spectroscopy (NIRcws) while phosphocreatine (PCr) was measured simultaneously by (31)P magnetic resonance spectroscopy. Muscle oxygen consumption (muscle VO(2)) and muscle oxidative capacity were evaluated using the rate of PCr resynthesis post-exercise. The forearm blood flow (FBF) index at the end of exercise was measured using NIRcws. There was a significant positive correlation between the Reoxy-rate, which ranged between 0.53% s(-1) and 12.47% s(-1), and the time constant for PCr resynthesis, which ranged between 17.8 s and 38.3 s (r(2)=0.939, P<0.001). At the end of the exercise, muscle VO(2) exceeded the resting level by approximately 25-fold, while the FBF index exceeded the resting level by only 3-fold on average. The Reoxy-rate closely correlated with muscle VO(2) (r(2)=0.727, P<0.05), but not with the FBF index. Also, the estimated O(2) balance (muscle VO(2) index/FBF index) was negatively correlated with the Reoxy-rate (r(2)=0.820, P<0.001). These results support our hypothesis that higher oxidative capacity muscle shows slower muscle reoxygenation after maximal short-term isometric exercise because the Reoxy-rate after this type of exercise may be influenced more by muscle VO(2) than by O(2) supply.
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8.
Re-evaluation of a possible proximity effect on muscular strength.
Kendler, BS, Keating, TM
Perceptual and motor skills. 2003;(2):371-4
Abstract
Inconsistent findings of a proximity effect of sucrose on muscular strength and a potential interaction of nutritional status prompted the current study. Double-blind, counterbalanced assessments of grip strength were performed with and without 76 subjects holding a container of sucrose. No main effect was found for proximity of glucose, and no interaction was found for prandial status.
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9.
Area density of smooth muscle cells and response to endothelin 1 in human hyperplastic prostate.
Ishigooka, M, Yazawa, H, Nakada, T, Zermann, DH
European urology. 2000;(4):494-8
Abstract
BACKGROUND alpha-Agonists and endothelins (ETs) are the only agents that have been proved to induce significant contraction of the prostate. Although the response to phenylephrine (PE) is dependent on the quality of smooth muscle (SM) within the prostate, it is not clear whether the response to ET-1 is also influenced by SM density. We evaluate the relationship between contractile responsiveness to ET-1 and the area density of SM of the human prostate. MATERIALS AND METHODS Specimens were obtained from 17 patients with prostatic hyperplasia that underwent transurethral resection of the prostate. Specimens were used for isometric tension study (PE, KCl and ET) and also for quantitative morphometric analysis. RESULTS PE and ET-1 induced dose-dependent contractile responses. There were no significant differences in the average maximum response (E(max)) to these two agents. E(max) to KCl and PE showed direct positive correlations with the area density of SM. E(max) to ET-1 also showed a positive correlation with the SM density, although this relationship was weaker than those for the other two agents. Moreover, there was a strong positive relationship between E(max) to PE, KCl and that to ET-1. CONCLUSIONS The area density of SM appeared to significantly influence the contractile response to ET-1 as well as the response to PE and KCl.