Lumbo-pelvic stability and electromyography of abdominal muscles in ballet dancers

Evaluating the ability to rectify and maintain lumbar adjustment can contribute toward the understanding of the behavior of abdominal muscles and their participation in the stability of pelvic muscles in dancers during the posterior pelvic tilt and double straight leg lowering tests. Nine healthy volunteers (male and female ballet dancers; age mean: 25.9 ±7.37 years) underwent maximal isometric voluntary contraction (MIVC), isometric voluntary contraction at 50% of MIVC, posterior pelvic tilt (PPT) and double straight leg lowering (DSLL) tests. The tests were carried out in a single day, with 3 repetitions each. During the tests, electromygraphic signals of the rectus abdominis, obliquus internus and obliquus externus were recorded. The signal acquisition system was made up of bipolar surface electrodes, electrogoniometer and an electromechanic device (pressure sensor), which were connected to a signal conditioner module. Root mean square values of each muscle during the DSLL and PPT were converted into percentage of activation of 50% MIVC. Lower back pressure was submitted to the same process. ANOVA with repeated measures was performed, with the level of significance set at p < 0.05. The results revealed that all dancers were able to maintain posterior pelvic tilt and there was trend toward greater activation of the bilateral obliquus internus muscle. In an attempt to keep the pelvic region stabilized during DSLL, there was a greater contribution from the obliquus externus muscle in relation to other abdominal muscles.

Electromyographic validation of the muscles deltoid (anterior portion) and pectoralis major (clavicular portion) in military press exercises with open grip

It was analized the deltoid muscle anterior portion and the pectoralis major clavicular portion in 24 male volunteers using a two-channel electromyograph TECA TE 4, and Hewllet Packard surface electrodes, in 4 modalities of military press exercises with open grip. The results showed high inactivity for PMC in almost all the modalities while DA developed very high levels of action potentials in all the modalities assessed.

Effect of occlusal splint treatment on the temperature of different muscles in patients with TMD

Purpose: The aim of this study was to evaluate the effect of occlusal splint treatment on the temperature of masseter (inferior, intermediate and superior), anterior temporal, digastric and trapezius muscles in patients with temporomandibular disorder (TMD). Materials and methods: Thirty patients (6 male and 24 female) aged from 16 to 57 years (mean 37.8. ± 11.4 years) were selected. The patients were diagnosed with muscular TMD by clinical examination (application of Research Diagnostic Criteria questionnaire and physical examination). Occlusal splints in acrylic resin were inserted in all patients with a weekly follow-up. The superficial thermography (°C) on the both sides of the muscles was performed using a digital thermometer in a controlled temperature room. This procedure was performed before occlusal splint insertion (patient with pain) and after the completion of the treatment (patient without pain). The data were analyzed by 2-way repeated-measures ANOVA and means were compared by Tukey HSD test (P< .05). Results: After occlusal splint treatment a significant increase in temperature was observed in each muscle, both in the right and left sides. When the muscles were compared in the same period (before or after therapy) there was no significant difference among them. Conclusion: It can be concluded that the use of occlusal splint promoted a significant increase on the muscles temperature. There was symmetry in the temperature of muscles on the right and left sides both before and after the treatment. © 2010 Japan Prosthodontic Society.

Electromyographic validation of the muscles deltoid (anterior portion) and pectoralis major (clavicular portion) in military press exercises with middle grip

With the objective to know the electromyographic activity normal parameters of the deltoid (anterior portion) and pectoralis major (clavicular portion) muscles in the different modalities of military press exercises with middle grip, we analyzed 24 male volunteers using a two-channel electromyograph TECA TE 4, and Hewllet Packard surface electrodes. It was observed high inactivity levels for PMC in almost all the modalities and the concentration in the active cases, mainly, in the weak potential, while DA presented very high levels of much strong action potentials in all the modalities assessed.

EMG activity of trunk stabilizer muscles during Centering Principle of Pilates Method

This study aimed to analyze the electromyographic (EMG) activity of iliocostalis lumborum (IL), internal oblique (IO) and multifidus (MU) and the antagonist cocontraction (IO/MU and IO/IL) during the performance of Centering Principle of Pilates Method. Participating in this study were eighteen young and physically fit volunteers, without experience in Pilates Method, divided in two groups: low back pain group (LBPG, n = 8) and control group (CG, n = 10). Two isometric contractions of IO muscles (Centering Principle) were performed in upright sitting posture. EMG signal amplitude was calculated by Root Mean Square (RMS), which was normalized by RMS maximum value. The common area method to calculate the antagonist cocontraction index was used. MU and IO activation and IO/MU cocontraction (. p < 0.05) were higher in CG. The CG therefore showed a higher stabilizer muscles recruitment than LBPG during the performance of Centering Principle of Pilates Method. © 2012 Elsevier Ltd.

Antagonist coactivation of trunk stabilizer muscles during Pilates exercises

The purpose of this study was to compare the antagonist coactivation of the local and global trunk muscles during mat-based exercises of Skilled Modern Pilates. Twelve women performed five exercises and concurrently, surface EMG from internal oblique (OI), multifidus (MU), rectus abdominis (RA) and iliocostalis lumborum (IL) muscles was recorded bilaterally. The percentage of antagonist coactivation between local (OI/MU) and global muscles (RA/IL) was calculated. Individuals new to the practice of these exercises showed differences in coactivation of the trunk muscles between the exercises and these results were not similar bilaterally. Thus, in clinical practice, the therapist should be aware of factors such as compensation and undesirable rotation movements of the trunk. Moreover, the coactivation of global muscles was higher bilaterally in all exercises analyzed. This suggests that the exercises of Skilled Modern Pilates only should be performed after appropriate learning and correct execution of all principles, mainly the Centering Principle. © 2013 Elsevier Ltd. All rights reserved.

Morphometry and expression of MyoD and Myogenin in white and red skeletal muscles of juvenile fish Colossoma macropomum (Cuvier 1818)

Colossoma macropomum, also known as tambaqui, is an economically important fish species, and interesting new studies have been published with the aim of improving the growth of this fish. In this work, we describe the morphometric characteristics, as well as the mRNA and protein expression levels of two myogenic regulatory factors (MRFs)-myod/MyoD and myogenin/Myogenin-in the white and red muscle types of tambaqui. A high proportion of white and red muscle fibers with large diameters suggest a hypertrophic growth process in the skeletal muscle during juvenile stages. Comparisons between muscle types showed that, in red muscle, myogenin transcript levels were significantly higher than those of myod. In contrast, MyoD protein levels were significantly higher than those of Myogenin in red muscle. These results suggest that in red and white muscles of juvenile tambaqui, independent post-transcriptional mechanisms for regulating MyoD and Myogenin expression may exist, which could be differentially activated during muscle growth. Furthermore, these data also suggest that specific control mechanisms may regulate distinct muscle phenotypes. © 2013 The Royal Swedish Academy of Sciences.

Electromyographic patterns of lower limb muscles during apprehensive gait in younger and older female adults

Objective: Investigate the influence of apprehensive gait on activation and cocontraction of lower limb muscles of younger and older female adults. Methods: Data of 17 younger (21.47±2.06 yr) and 18 older women (65.33±3.14. yr) were considered for this study. Participants walked on the treadmill at two different conditions: normal gait and apprehensive gait. The surface electromyographic signals (EMG) were recorded during both conditions on: rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), tibialis anterior (TA), gastrocnemius lateralis (GL), and soleus (SO). Results: Apprehensive gait promoted greater activation of thigh muscles than normal gait (F=5.34 and p=0.007, for significant main effect of condition; RF, p=0.002; VM, p<0.001; VL, p=0.003; and BF, p=0.001). Older adults had greater cocontraction of knee and ankle stabilizer muscles than younger women (F=4.05 and p=0.019, for significant main effect of groups; VM/BF, p=0.010; TA/GL, p=0.007; and TA/SO, p=0.002). Conclusion: Apprehensive gait promoted greater activation of thigh muscles and older adults had greater cocontraction of knee and ankle stabilizer muscles. Thus, apprehensive gait may leads to increased percentage of neuromuscular capacity, which is associated with greater cocontraction and contribute to the onset of fatigue and increased risk of falling in older people. © 2013 Elsevier Ltd.

Influence of spray mixture volume and flight height on herbicide deposition in aerial applications on pastures

The objective of the present study was to analyze the influence of spray mixture volume and flight height on herbicide deposition in aerial applications on pastures. The experimental plots were arranged in a pasture area in the district of Porto Esperidião (Mato Grosso, Brazil). In all of the treatments, the applications contained the herbicides aminopyralid and fluroxypyr (Dominum) at the dose of 2.5 L c.p. ha-1, including the adjuvant mineral oil (Joint Oil) at the dose of 1.0 L and a tracer to determine the deposition by high-performance liquid chromatography (HPLC) (rhodamine at a concentration of 0.6%). The experiment consisted of nine treatments that comprised the combinations of three spray volumes (20, 30 and 50 L ha-1) and three flight heights (10, 30 and 40 m). The results showed that, on average, there was a tendency for larger deposits for the smallest flight heights, with a significant difference between the heights of 10 and 40 m. There was no significant difference among the deposits obtained with the different spray mixture volumes.

Differential Expression of Myogenic Regulatory Factor Genes in the Skeletal Muscles of Tambaqui Colossoma macropomum (Cuvier 1818) from Amazonian Black and Clear Water

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

Decreased rate of protein synthesis, caspase-3 activity, and ubiquitin-proteasome proteolysis in soleus muscles from growing rats fed a low-protein, high-carbohydrate diet

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fatigue Behavior of Weld Repaired AISI 4130 Aeronautic Steel Used in Critical Flight Safety Structures

Since the 1950s, fatigue is the most important project and operational consideration for both civil and military aircrafts. For some aircraft models the most loaded component is one that supports the motor: the Motor Cradle. Because they are considered critical to the flight safety the aeronautic standards are extremely rigorous in manufacturing them by imposing a zero index of defects on the final weld quality (Safe Life), which is 100% inspected by Non-Destructive Testing/NDT. This study has as objective to evaluate the effects of up to four successive TIG welding repairs on the axial fatigue strength of an AISI 4130 steel. Tests were conducted on hot-rolled steel plate specimens, 0.89 mm thick, with load ratio R = 0.1, constant amplitude, at 20 Hz frequency and in room temperature, in accordance with ASTM E466 Standard. The results were related to microhardness and microstructural and geometric changes resulting from welding cycles.

Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase

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

Verbal and visual stimulation effects on rectus femoris and biceps femoris muscles during isometric and concentric

Background: Coactivation may be both desirable (injury prevention) or undesirable (strength measurement). In this context, different styles of muscle strength stimulus have being investigated. In this study we evaluated the effects of verbal and visual stimulation on rectus femoris and biceps femoris muscles contraction during isometric and concentric. Methods: We investigated 13 men (age =23.1 ± 3.8 years old; body mass =75.6 ± 9.1 kg; height =1.8 ± 0.07 m). We used the isokinetic dynamometer BIODEX device and an electromyographic (EMG) system. We evaluated the maximum isometric and isokinetic knee extension and flexion at 60°/s. The following conditions were evaluated: without visual nor verbal command (control); verbal command; visual command and; verbal and visual command. In relation to the concentric contraction, the volunteers performed five reciprocal and continuous contractions at 60°/s. With respect to isometric contractions it was made three contractions of five seconds for flexion and extension in a period of one minute. Results: We found that the peak torque during isometric flexion was higher in the subjects in the VVC condition (p > 0.05). In relation to muscle coactivation, the subjects presented higher values at the control condition (p > 0.05). Conclusion: We suggest that this type of stimulus is effective for the lower limbs.

Interrelationships Between Bones, Muscles, and Performance: Biting in the Lizard Tupinambis merianae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)