Effect of short-term creatine supplementation on markers of skeletal muscle damage after strenuous contractile activity

The protective effect of short-term creatine supplementation (CrS) upon markers of strenuous contractile activity-induced damage in human and rat skeletal muscles was investigated. Eight Ironman triathletes were randomized into the placebo (Pl; n = 4) and creatine-supplemented (CrS; n = 4) groups. Five days prior to the Ironman competition, the CrS group received creatine monohydrate (20 g day(-1)) plus maltodextrin (50 g) divided in two equal doses. The Pl group received maltodextrin (50 g day(-1)) only. The effect of CrS (5 g day(-1)/kg body weight for 5 days) was also evaluated in a protocol of strenuous contractile activity induced by electrical stimulation in rats. Blood samples were collected before and 36 and 60 h after the competition and were used to determine plasma activities of creatine kinase (CK), lactate dehydrogenase (LDH), aldolase (ALD), glutamic oxaloacetic acid transaminase (GOT), glutamic pyruvic acid transaminase (GPT), and C-reactive protein (CRP) level. In rats, plasma activities of CK and LDH, muscle vascular permeability (MVP) using Evans blue dye, muscle force and fatigue were evaluated. Activities of CK, ALD, LDH, GOT, GTP, and levels of CRP were increased in the Pl group after the competition as compared to basal values. CrS decreased plasma activities of CK, LDH, and ALD, and prevented the rise of GOT and GPT plasma activities. In rats, CrS delayed the fatigue, preserved the force, and prevented the rise of LDH and CK plasma activities and MVP in the gastrocnemius muscle. CrS presented a protective effect on muscle injury induced by strenuous contractile activities.

Creatine supplementation reduces plasma levels of pro-inflammatory cytokines and PGE(2) after a half-ironman competition

Objective. The effect of creatine supplementation upon plasma levels of pro-inflammatory cytokines: Interleukin (IL) 1 beta and IL-6, Tumor Necrosis Factor alpha (TNF alpha), and Interferon alpha (INF alpha) and Prostaglandin E(2) (PGE(2)) after a half-ironman competition were investigated. Methods. Eleven triathletes, each with at least three years experience of participation in this sport were randomly divided between the control and experimental groups. During 5 days prior to competition, the control group (n = 6) was supplemented with carbohydrate (20g center dot d(-1)) whereas the experimental group (n = 5) received creatine (20 center dot d(-1)) in a double-blind trial. Blood samples were collected 48h before and 24 and 48h after competition and were used for the measurement of cytokines and PGE(2). Results. Forty-eight hours prior to competition there was no difference between groups in the plasma concentrations (pg center dot ml(-1), mean +/- SEM) of IL-6 (7.08 +/- 0.63), TNF alpha (76.50 +/- 5.60), INF alpha (18.32 +/- 1.20), IL-1 beta (23.42 +/- 5.52), and PGE(2) (39.71 +/- 3.8). Twenty-four and 48h after competition plasma levels of TNF alpha, INF alpha, IL-1 beta and PGE(2) were significantly increased (P < 0.05) in both groups. However, the increases in these were markedly reduced following creatine supplementation. An increase in plasma IL-6 was observed only after 24h and, in this case, there was no difference between the two groups. Conclusion. Creatine supplementation before a long distance triathlon competition may reduce the inflammatory response induced by this form of strenuous of exercise.

Effect of Cluster Multi-Diode Light Emitting Diode Therapy (LEDT) on Exercise-Induced Skeletal Muscle Fatigue and Skeletal Muscle Recovery in Humans

Background and Objectives: There are some indications that low-level laser therapy (LLLT) may delay the development of skeletal muscle fatigue during high-intensity exercise. There have also been claims that LED cluster probes may be effective for this application however there are differences between LED and laser sources like spot size, spectral width, power output, etc. In this study we wanted to test if light emitting diode therapy (LEDT) can alter muscle performance, fatigue development and biochemical markers for skeletal muscle recovery in an experimental model of biceps humeri muscle contractions. Study Design/Materials and Methods: Ten male professional volleyball players (23.6 [SD +/- 5.6] years old) entered a randomized double-blinded placebo-controlled crossover trial. Active cluster LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW, 30 seconds total irradiation time, 41.7J of total energy irradiated) or an identical placebo LEDT was delivered under double-blinded conditions to the middle of biceps humeri muscle immediately before exercise. All subjects performed voluntary biceps humeri contractions with a workload of 75% of their maximal voluntary contraction force (MVC) until exhaustion. Results: Active LEDT increased the number of biceps humeri contractions by 12.9% (38.60 [SD +/- 9.03] vs. 34.20 [SD +/- 8.68], P = 0.021) and extended the elapsed time to perform contractions by 11.6% (P = 0.036) versus placebo. In addition, post-exercise levels of biochemical markers decreased significantly with active LEDT: Blood Lactate (P = 0.042), Creatine Kinase (P = 0.035), and C-Reative Protein levels (P = 0.030), when compared to placebo LEDT. Conclusion: We conclude that this particular procedure and dose of LEDT immediately before exhaustive biceps humeri contractions, causes a slight delay in the development of skeletal muscle fatigue, decreases post-exercise blood lactate levels and inhibits the release of Creatine Kinase and C-Reative Protein. Lasers Surg. Med. 41:572-577, 2009. (C) 2009 Wiley-Liss, Inc.

Comparison between cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) in short-term skeletal muscle recovery after high-intensity exercise in athletes-preliminary results

In the last years, phototherapy has becoming a promising tool to improve skeletal muscle recovery after exercise, however, it was not compared with other modalities commonly used with this aim. In the present study we compared the short-term effects of cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) with placebo LEDT on biochemical markers related to skeletal muscle recovery after high-intensity exercise. A randomized double-blind placebo-controlled crossover trial was performed with six male young futsal athletes. They were treated with CWIT (5A degrees C of temperature [SD +/- 1A degrees]), active LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW of output power, 30 s of irradiation time per point, and 41.7 J of total energy irradiated per point, total of ten points irradiated) or an identical placebo LEDT 5 min after each of three Wingate cycle tests. Pre-exercise, post-exercise, and post-treatment measurements were taken of blood lactate levels, creatine kinase (CK) activity, and C-reactive protein (CRP) levels. There were no significant differences in the work performed during the three Wingate tests (p > 0.05). All biochemical parameters increased from baseline values (p < 0.05) after the three exercise tests, but only active LEDT decreased blood lactate levels (p = 0.0065) and CK activity (p = 0.0044) significantly after treatment. There were no significant differences in CRP values after treatments. We concluded that treating the leg muscles with LEDT 5 min after the Wingate cycle test seemed to inhibit the expected post-exercise increase in blood lactate levels and CK activity. This suggests that LEDT has better potential than 5 min of CWIT for improving short-term post-exercise recovery.

Effects of weight loss on the cardiac parameters of obese dogs

A obesidade é uma das doenças nutricionais mais frequentemente observada em cães e pode provocar sérios problemas de saúde, como os distúrbios cardiovasculares. Realizou-se este estudo visando avaliar algumas das possíveis alterações estruturais e funcionais cardíacas decorrentes da correção da obesidade canina. Para isso foram utilizados 18 cães obesos divididos pelo peso corporal em Grupo I (até 15kg), Grupo II (entre 15,1 e 30 kg) e Grupo III (acima de 30 kg). Os animais foram submetidos à restrição calórica de forma a perderem 15% do peso vivo. Foram realizados os exames ecocardiográfico em modo-M, eletrocardiográfico e mensuração da pressão arterial dos animais antes do início do tratamento da obesidade e após atingirem o peso meta. Os resultados revelaram que após a redução de peso ocorreram diminuições significativas da espessura da parede livre do ventrículo esquerdo durante a sístole e diástole no Grupo III, diminuição da pressão arterial sistólica no Grupo III e também da pressão arterial média no Grupo II. Assim, concluiu-se que a perda de peso pode reverter as alterações estruturais cardíacas, como a hipertrofia excêntrica do ventrículo esquerdo em cães obesos acima de 30 kg, como também reduzir a pressão arterial sistêmica em cães obesos submetidos à restrição calórica mediante administração de dieta hipocalórica.

Isolamento e caracterização ultraestrutural de folículos pré-antrais de vacas da raça Nelore (Bos taurus indicus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da laserterapia de baixa potência sobre a fadiga do músculo quadríceps de indivíduos jovens

The objective of this study was to evaluate the effect of low laser power on the performance of anaerobic endurance of the quadriceps muscle in young subjects. Low-level laser therapy (LLLT) appears to decrease some indices of muscle fatigue. Most of these effects may be due to the influence of the laser on the muscles predominantly aerobic. Animal studies and clinical trials have already shown that the laser can improve the efficiency of mitochondrial metabolism for the resynthesis of adenosine triphosphate and thus slow down - or minimize, the deleterious effects of muscle fatigue. This research was characterized as an experimental study of the controlled clinical trial, randomized, blinded, attended by 93 volunteers, military, with ages between 18 and 19 years. The subjects were randomly allocated into three groups: Control (G1), Placebo (G2) and Laser (G3). All volunteers underwent an anthropometric assessment and a protocol Fatigue. This protocol was applied to an initial assessment (AV-1) for the collection of baseline data, and a final evaluation (AV-2). As the study variables, we used the blood lactate concentrations and indices of muscle power, as average power and peak velocity. The fatigue protocol consisted of a test of speed with twenty repetitions, performed on an exercise machine leg press 45º . In conclusion, it was found that, in this study, LLLT caused a significant increase in the Average of the Averages Powers, phase eccentric exercise in leg press 45º performed by young individuals

Efeito da estimulação transcraniana por corrente contínua anódica sobre o controle do movimento em para-halterofilistas

Introduction: The sport practiced by people with disabilities has been growing in recent years. Consequently, advances in assessment and training methods have emerged. However, the paralympic sport keeps in tow these advances, with few specific studies that consider disability as intervening factor. The transcranial direct current stimulation (tDCS) is a technique that has proven to be capable of modulating brain function. Studies show beneficial effects of tDCS on muscle strength, power and fatigue during exercise. Objective: Investigate de the effect of tDCS on movement control in para-powerlifters. Methods: Eight subjects underwent two sessions of motion capture, which previously applied the anodic tDCS or sham sessions in the cerebellum. Three movements were performed with increasing load between 90-95% of 1MR. The movements were recorded by an 10 infrared cameras system which reconstructed the 3D trajectory of markers placed on the bar. Results: There have been changes between the anodic and sham conditions over bar level (initial, final, maximum during the eccentric and concentric phase) and in the difference between the final and initial bar level. Moreover, there was difference in bar level (final and during the eccentric phase) comparing athletes amputees and les autres. Conclusion: The findings of this study suggest that tDCS applied prior to the exercise over the cerebellum in para-powerlifters acts differently according to disability

Simulação computacional da interação fluido-estrutura em bombas de cavidades progressivas

The pumping through progressing cavities system has been more and more employed in the petroleum industry. This occurs because of its capacity of elevation of highly viscous oils or fluids with great concentration of sand or other solid particles. A Progressing Cavity Pump (PCP) consists, basically, of a rotor - a metallic device similar to an eccentric screw, and a stator - a steel tube internally covered by a double helix, which may be rigid or deformable/elastomeric. In general, it is submitted to a combination of well pressure with the pressure generated by the pumping process itself. In elastomeric PCPs, this combined effort compresses the stator and generates, or enlarges, the clearance existing between the rotor and the stator, thus reducing the closing effect between their cavities. Such opening of the sealing region produces what is known as fluid slip or slippage, reducing the efficiency of the PCP pumping system. Therefore, this research aims to develop a transient three-dimensional computational model that, based on single-lobe PCP kinematics, is able to simulate the fluid-structure interaction that occurs in the interior of metallic and elastomeric PCPs. The main goal is to evaluate the dynamic characteristics of PCP s efficiency based on detailed and instantaneous information of velocity, pressure and deformation fields in their interior. To reach these goals (development and use of the model), it was also necessary the development of a methodology for generation of dynamic, mobile and deformable, computational meshes representing fluid and structural regions of a PCP. This additional intermediary step has been characterized as the biggest challenge for the elaboration and running of the computational model due to the complex kinematic and critical geometry of this type of pump (different helix angles between rotor and stator as well as large length scale aspect ratios). The processes of dynamic generation of meshes and of simultaneous evaluation of the deformations suffered by the elastomer are fulfilled through subroutines written in Fortan 90 language that dynamically interact with the CFX/ANSYS fluid dynamic software. Since a structural elastic linear model is employed to evaluate elastomer deformations, it is not necessary to use any CAE package for structural analysis. However, an initial proposal for dynamic simulation using hyperelastic models through ANSYS software is also presented in this research. Validation of the results produced with the present methodology (mesh generation, flow simulation in metallic PCPs and simulation of fluid-structure interaction in elastomeric PCPs) is obtained through comparison with experimental results reported by the literature. It is expected that the development and application of such a computational model may provide better details of the dynamics of the flow within metallic and elastomeric PCPs, so that better control systems may be implemented in the artificial elevation area by PCP

Ultrastructural analysis of spermiogenesis in the neotropical cichlid Cichla kelberi Kullander & Ferreira, 2006 (Perciformes: Cichlidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito imediato da estimulação elétrica neuromuscular seletiva do músculo VMO em pacientes com síndrome da dor femoropatelar

Patellofemoral pain syndrome (PFPS) is described as anterior or retropatellar pain knee in the absence of other pathologies and is frequently associated with dysfunction of the vastus medialis oblique (VMO). However, several studies have demonstrated the inability to selectively activate this muscle through exercise. To evaluate the effect of Neuromuscular Electrical Stimulation (NMES) selective VMO in women with syndrome. We evaluated thirty-eight women: twenty in the control group (24.15 ± 2.60 years) and eighteen diagnosed with PFPS (25.56 ± 3.55 years). Both groups were evaluated before and after a protocol of electro stimulation. To measure for comparing groups before and after treatment, we assessed the extensor torque concentric and eccentric knee through an isokinetic dynamometer, the intensity (Root Mean Square - RMS) and the onset of activation (onset) of VMO compared to the vastus lateralis (VL) in two types of exercise: open and closed kinetic chain. . Statistical analysis was performed using SPSS 15.0, with a significance level of 5%. Results: Our data showed an increase in the intensity of activation (RMS) of the VMO muscle after NMES in both study groups. During concentric contraction the RMS of the VMO before the NMES was 105.69 ± 32.26 μV and after a single intervention was 122.10 ± 39.62 μV (p = 0.048) for the control group. In the group with PPS, we found a similar behavior, with RMS of the VMO before NMES of 96.25 ± 18.83 μV and 139.80 ± 65.88 μV after the intervention (p = 0.0001). However, there was no evidence in the RMS value of VL muscle. The onset was calculated by subtracting the onset of VL by the onset of VMO. For the group with PFPS, the onset before the intervention was -0.007 ± 0.14 ms, indicating a delay of the VMO relative to VL, and after NMES was 0.074 ± 0.09 ms (p = 0.016), showing an activation previous VMO to VL. The same occurred for the control group. We also observed that NMES increased knee extensor power during the concentric contraction in both groups. Before the intervention the mean power was 28.97 ± 9.01 W for the PPS group and after NMES was 34.38 ± 7.61 W (p = 0.0001). Conclusion: We observed an increase in electromyographic activity of the VMO and also an anticipatory effect of this muscle

Efeitos do alongamento e do aquecimento no desempenho isocinético e na atividade eletromiográfica do músculo bíceps femoral ensaio clínico randomizado

To evaluate the effects of warm-up and stretching, singly or combined, on isokinetic performance and electromyographic activity of the biceps femoris. Materials and methods: Sixty-four volunteers of both sexes, with mean age of 23,1 ± 3,5 years and mean body mass index of 23,5 ± 2,5 Kg/m2 were randomly assigned into 4 groups: control, warm-up (stationary bicycle for 10 minutes), stretching (4 sets of 30 seconds of hamstring muscles static stretching) and warm-up + stretching. All the volunteers were submitted to evaluation pre and post-intervention of the muscle latency time and biceps femoris RMS and the passive torque, peak torque and power of the hamstring muscles. Results: The warm-up + stretching group had reduction of muscle latency time. There was a reduction of RMS during passive torque evaluation in stretching group. The RMS during isometric evaluation was reduced in all experimental groups. The RMS during eccentric evaluation showed reduction in control and warm-up + stretching groups. The passive torque and the eccentric peak torque had no significant differences pre to post-intervention in any group. There was reduction in isometric peak torque in all groups. Conclusion: The warm-up and stretching, when applied in combination can reduce the muscle latency time; stretching protocol promoted neural changes; the protocols used did not alter the muscle viscoelastic properties

Efeitos agudos do alongamento estático antes e após exercício e as características neuromusculares do membro inferior: estudo controlado, randomizado e cego

Objective: To evaluate the acute effects of static stretching before and after isokinetic exercise, neuromuscular and biomechanical properties of muscles Biceps Femoris (BF) and semitendinosus (ST). Methods: Eighty-nine volunteers of both genders, healthy and physically active, with a mean age of 22.52 ± 2.6 years and mean BMI 23.86 ± 3.2 kg/m² were randomized into 4 groups: Control Group (CG) made only one Protocol Exercise (PE) without performing the stretching, the Experimental Group 1 (EG1) did stretching before PE; EG2 did the stretching after PE and EG3 did stretching before and after PE. The volunteers were evaluated on the following variables: Range of motion (ROM), soreness, dynamometric variables concentric and eccentric, Neuromuscular Latency Time (NLT) and electromyographic. In the data analysis was assigned a significance level of 5%. Results: ADM and TLNM reported significant reduction in CG, but remained unchanged in GE with p<0,05 and p<0,01, respectively. As for the soreness, no differences between the groups. The electromyographic activity of the BF and ST, in the concentric phase, showed a significant decrease in all groups (p<0,01). However, in the eccentric phase, ST revealed reduction in all groups (p <0.01), except for the CG, while the BF remained unchanged in all groups. The PT showed significant reduction in both conditions (concentric and eccentric) for all groups, with no difference between them (p<0,01). Conclusion: The results of this study do not favor the use of static stretching, even of short duration, before physical activity. However, after exercise or at times unrelated to the sport, he should be given with the aim of avoiding muscle shortening

Efeito da crioterapia e da laserterapia na resposta ao dano muscular induzido pelo exercício excêntrico: ensaio clínico e randomizado

Exercise-induced muscle damage mainly affects individuals who returned to physical activity after a time without practicing it or had some kind of exhaustive exercise, particularly eccentric exercise. To evaluate the effect of cryotherapy and laser therapy in response to muscle damage induced by eccentric exercise on the biceps muscle. This was a randomized clinical trial consisting of 60 female subjects. All subjects initially underwent an evaluation consisting of perimetry, measurement of pain sensation (via algometry and visual analogue scale), electromyography and dynamometry. Then the subjects performed an exercise protocol on the isokinetic dynamometer consisting of 2 sets of 10 eccentric elbow flexors contraction at 60 °/s. Completed this protocol, an intervention was held according to a previously random group distribution: control group (no intervention), cryotherapy group and laser therapy group. Finally, subjects were re-evaluated immediately and 48 hours after the intervention protocol, except for Visual Analogue Scale (VAS), which was also evaluated 24 hours after exercise. The circumference of the limb, the pain sensation (VAS and algometry), the muscle activation amplitude (via Root Mean Square - RMS), median frequency, peak torque normalized per body weight, average peak torque, power and work were analyzed. The median frequency immediately after the intervention protocol on the cryotherapy group was the only variable that showed inter and intra-group differences; the remaining variables showed only intragroup differences. The perimetry values did not change immediately after the protocol on the groups which underwent cryotherapy and laser therapy, however, there was an increase after 48 hours; algometry values decreased in all groups for 48 hours and the VAS values increased 24 and 48 hours also for all groups. Regarding RMS no significant change was observed. For dynamometry, peak torque normalized per body weight and average peak torque had a similar behavior, with a reduction in the post protocol that has remained after 48 hours. For the power and work, a decrease was observed immediately after the protocol with a further reduction after 48 hours. Cryotherapy and laser therapy does not alter the muscle damage response, except for the perimetry values immediately after exercise.

Electronic states in quantum rings: electric field and eccentricity effects

The polarization effects of in-plane electric fields and eccentricity on electronic and optical properties of semiconductor quantum rings (QRs) are discussed within the effective-mass approximation. As eccentric rings may appropriately describe real (grown or fabricated) QRs, their energy spectrum is studied. The interplay between applied electric fields and eccentricity is analysed, and their polarization effects are found to compensate for appropriate values of eccentricity and field intensity. The importance of applied fields in tailoring the properties of different nanoscale materials and structures is stressed.