Leg muscles recruitment pattern in soccer players and active individuals during isometric contractions

This study aimed to compare the torque, torque ratio (Hamstrings:Quadriceps - H:Q), electromyographic (EMG) activity and EMG ratio (knee flexors:knee extensors EMG) in soccer players (SG, N=10) and active subjects (AG, N=10). Subjects performed three maximal voluntary isometric knee extensions and flexions at 45° and 90° to determine the peak torque and EMG activity. Torque and EMG activity of the knee flexor (biceps femoris [BF] and semitendinosus [ST]) were divided by the torque and EMG activity of the knee extensor (vastuls lateralis [VL] and rectus femoris [RF]) to calculate torque ratios (H:Q) and EMG ratios (BF:VL, BF:RF, ST:VL, ST:RF). The flexion torque was significantly higher for SG (p<0.05) in 45° and 90°. EMG activity for SG was significantly higher in agonist contractions for VL, RF and ST, and significantly lower in antagonist contractions for RF and ST when compared to AG Torque and EMG ratios were similar between groups and there were good correlations between torque ratio and BF:VL ratio (r=0.71, p=0.02) and BF:RF ratio (r=0.81, p=0.004) at 45. The EMG results could overestimate the joint balance calculated using torque ratios. Differences in recruitment pattern between soccer players and non-athletes can be related to the training routines and the EMG ratios presents applicable in trained populations.

Realimentação derivativa e modelo fuzzy Takagi-Sugeno paracontrole da articulação do joelho de pacientes paraplégicos com o uso de acelerômetros

Feedback control systems have been used to move the muscles and joints of the limbs of paraplegic patients. The feedback signal, related to the knee joint angle, can be obtained by using an electrogoniometer. However, the use of accelerometers can help the measurements due the facility of adhering these devices to the skin. Accelerometers are also very suitable for these applications due their small dimensions and weight. In this paper a new method for designing a control system that can vary the knee joint angle using Functional Electrical Stimulation (FES) is presented, as well as a simulation with parameters values available in the literature. The nonlinear control system was represented by a Takagi-Sugeno fuzzy model and the feedback signals were obtained by using accelerometers. The design method considered all plant nonlinearities and was efficient and reliable to control the leg position of a paraplegic patient with the angle of the knee ranging from 0° to 30°, considering electric stimulation at the quadriceps muscle. The proposed method is viable and offers a new alternative for designing control systems of the knee joint angle using more comfortable sensors for the patients.

Are early and late rate of force development differently influenced by fast-velocity resistance training?

This study examined the effect of fast-velocity concentric isokinetic resistance training (FV) on the rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising muscle force. Nine men participated in a 6-week resistance training intervention for the lower body, and nine matched subjects participated as controls (CON). During concentric isokinetic (180°s-1) knee extension training, subjects were instructed to do each contraction 'as fast and forcefully as possible'. Maximal muscle strength (MVC) and RFD (0-10, 0-20, ..., 0-250 ms from the onset of contraction) were measured during maximal voluntary isometric contraction of the knee extensors (KE). There were no significant changes in MVC of KE in both groups after intervention (FV = 314·2 ± 101·1 versus 338·7 ± 88·0 N{bullet operator}m, P>0·05; CON = 293·3 ± 94·8 versus 280·0 ± 72·2 N{bullet operator}m, P>0·05). The RFD increased 39-71% at time intervals up to 90 ms from the onset of the contraction (P<0·05), whereas no change occurred at later time intervals. Similarly, relative RFD (i.e.%MVC{bullet operator}s-1) (RFDr) increased 33-56% at time intervals up to 70 ms from the onset of the contraction (P<0·05). It can be concluded that a short period of resistance training performed with concentric fast-velocity isokinetic muscle contractions is able to enhance RFD and RFDr obtained at the early phase of rising muscle force. © 2013 The Authors Clinical Physiology and Functional Imaging © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Análise teórica e experimental da energia despendida no exercício de extensão do joelho para aplicações em engenharia de reabilitação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of autohemotherapy on hematological responses in Wistar female rats Autohemotherapy in rats

Introduction: Autohemotherapy is a type of treatment that have acquired an opposite role and have presented its efficiency strived by the medical community for many reasons. In this study we aimed to evaluate the effects of authohaemotherapy on hematological response. Method: We used Wistar female rats (300g). The study consisted in a control group and a treatment group, blood samples were collected at the first day and at the eighth day after the application. In the both groups we collected 300 μl of blood from each rat through a syringe with a previously prepared solution of 30 μl of sodium citrate 3.2%. In the autohemotherapy group the blood sample was immediately injected in the quadriceps muscle on the back of the thigh hind limb. Rats from the control group did not receive intramuscular blood application. The cellular count was done through flow cytometry and the samples were dosed for immunoglobulin. Results: In the both groups we observed increased production of erytrocites, hemoglobin and platelet (p<0.05). However, there was reduction of basophil in the control group and reduction of lymphocyte, monocyte and neutrophil in the both groups. No effects were observed in IgA, IgG and IgM levels. Conclusion: Autohemotherapy did not influence hematological responses in Wistar female rats.

Associações anestésicas baseadas em fármacos dissociativos reduzem a pressão intraocular (PIO) em coelhos

The aim of this study was evaluate the effects of three anesthetic combinations, ketamine-midazolam, ketamine-xylazine and tiletamine-zolazepam, on IOP in rabbits. In a experimental, blind, randomized, crossover study, six rabbits were anesthetized with each of 3 treatments in random order. Groups KM (ketamine, 30 mg/kg + midazolam, 1 mg/kg); KX (ketamine, 30 mg/kg + xylazine, 3 mg/kg); and TZ (tiletamine + zolazepam, 20 mg/kg). The drugs were mixed in the same syringe injected intramuscularly (IM) into the quadriceps muscle. IOP was measured before drug administration (baseline) and at 5-minute intervals for 30 minutes. The data were analyzed by a 2-way repeated measures ANOVA followed by Bonferroni test. All groups had significant decreases in IOP compared to baseline (p < 0.001). There was no difference between groups at any of the time points assessed (p > 0.05). Administration of either ketamine-midazolam, ketamine-xylazine, or tiletamine-zolazepam similarly decrease IOP in rabbits within 30 minutes of injection.

Análise da modulação do reflexo H do vasto medial em mulheres com síndrome da dor femoropatelar

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

Exploratory study of electromyographic behavior of the vastus medialis and vastus lateralis at neuromuscular fatigue onset

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Proporção tecidual da perna de caprinos jovens em função do grupo racial, peso de abate e sexo

To evaluate the effect of breed group, slaughter weight and sex on tissue proportion of the leg and muscle, bone and fat ratio in confined kids, seventy-four goats of both sex were used and divided among breed groups: Alpine (A), ½ Nubian + ½ Alpine (½ ANA), ½ Boer + ½ Alpine (½ BA), ¾ Boer + ¼ Alpine (¾ BA) and ½ Nubian + ¼ Alpine + ¼ Boer, (Three cross - TC), at three slaughter weights (25, 30 and 35 kg). Leg represented 31.01% of half carcass, where 62.29% was total muscle, 21.45% total bone and 8.35% total fat. Alpine animals had higher bone weight than other groups. Male kids had higher muscle and bone proportion, whereas females had higher subcutaneous and intramuscular fat in leg. The percentage of total weight of the muscle, five muscles, adductor muscle, quadriceps muscle and femur were higher in the slaughter weights of 25 and 30 kg.

Rapid hamstrings/quadriceps strength capacity in professional soccer players with different conventional isokinetic muscle strength ratios

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

Does muscle imbalance affect fatigue after soccer specific intermittent protocol?

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

EPA protects against muscle damage in the mdx mouse model of Duchenne muscular dystrophy by promoting a shift from the M1 to M2 macrophage phenotype

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

Moderate intensity and volume downhill run does not impair knee joint stability at early and late phases of quadriceps/hamstrings contraction

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

Onset of quadriceps and torque variation in individuals with patellofemoral pain during stair ascent

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)