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)

Test-retest reliability of electromyographic variables of masseter and temporal muscles in patients with cerebral palsy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Hip muscles strength and activation in older fallers and non-fallers

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)

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)

Electrical activity of the orbicularis muscles before and after installation of ocular prostheses

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

Electromyographic study of the longissimus dorsi and iliocostalis lumborum muscles during knee flexion and extension on a plain and on a tilt Roman table

The objective of this paper was to analyse the activity of the longissimus dorsi and the iliocostalis lumborum muscles--components of the erector spinae muscle--in order to determine: their action potentials during the use of a plain and a tilt Roman table; 2) to compare the action potentials of the two muscles; 3) to verify if the action potential of these two muscles remain constant during the arc of movement--knee flexion and extension--divided into angle ranges, and 4) to compare the action potentials of the muscles in movements performed in a free manner and against resistance. Twenty-three young volunteers were studied electromyographically and each muscle received a needle electrode (Mise) and a surface electrode. The results showed that the table model did not determine any difference in the action potential of the muscles and that, on average, the iliocostalis lumborum muscle developed a slightly higher action potential than the longissimus dorsi muscle during the free flexion of knees on the plain table. In more than 70% of the cases, there was no difference between the action potential of the muscles over the various angle ranges of knee flexion and extension. Relatively higher action potentials were recorded during knee flexion and extension against resistance than during the same movements performed in a free manner. This shows that the paravertebral musculature responds better to an overload (8 kg) imposed on the knee flexor group, confirming the stabilizing role of the longissimus dorsi and iliocostalis lumborum muscles during knee flexion and extension on a Roman table.

Morphological characteristics of neuromuscular junctions of the opossum (Didelphis albiventris) extraocular muscles: a scanning-electron-microscopic study

Three types of neuromuscular junctions were described in the extraocular muscles of the opossum. The present study demonstrates the three-dimensional characteristics of these neuromuscular junctions after HCl connective tissue digestion. Adult opossum of both sexes were used and the neuromuscular junctions of the extraocular muscles were examined after removal of the intramuscular connective tissue and basal layer. This material was examined with a scanning electron microscope. Two types of 'en plaque' neuromuscular junction were described: the continuous type revealed elongated and branched primary synaptic grooves separated from each other by sarcolemma protuberances with different sizes, and the discontinuous or punctiform type which presents very shallow and discontinuous grooves when compared with the former. The multiple neuromuscular junctions were observed as two or three junctions associated with the same muscular fiber. The multiple junctions were present in thin fibers (around 11 microm caliber); the en plaque junctions were associated with large diameter fibers (around 21 microm). This study confirms and reveals the detailed morphological characteristics of the three neuromuscular junction types previously described by transmission electron microscope in the extraocular muscles of opossum.

Electromyographic validation of the trapezius and serratus anterior muscles in military press exercises with open grip

It was studied the trapezius muscle and serratus anterior muscle in 24 male volunteers using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes, during the execution of four different modalities of military press exercises with open grip. The results showed that TS acted significantly in the modalities standing and sitting press behind neck, while SI acted in all the modalities, i.e., standing and sitting press behind neck and forward, justifying their inclusion as basic exercises for physical conditioning programmes.

Evaluation of silent period on masticatory cycles of different muscles in dentate oral contraceptives users and nonusers

The aim of this study was to evaluate the influence of oral contraceptive use on the silent period (SP) of anterior temporal and masseter muscles during the menstrual cycle. Totally, 28 women on reproductive age were selected including 15 nonusers of any hormone and 13 contraceptive users. All patients were dentate without muscular temporomandibular disorders. Electromyography (SP test) of the anterior temporal and masseter muscles was conducted every week during three consecutive menstrual cycles at 1(st) day of menstruation (P1), 7(th) day (P2), 14(th) day (P3) and 21(st) day (P4). The SP values in the anterior temporal and masseter muscles were measured at both sides. The SP values of the right side (13.49 ms) at P2 were significantly different compared to the left side (12.28 ms). However, there was no significant difference on the interactions among the three factors. It can be concluded that the SP values in healthy women in reproductive age may not be influenced by the menstrual cycle with similar results for both muscles.

Effects of neuromuscular electrical stimulation on the masticatory muscles and physiologic sleep variables in adults with cerebral palsy: a novel therapeutic approach

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Downhill running excessive training inhibits hypertrophy in mice skeletal muscles with different fiber type composition

The aim of this study was to verify the effects of running overtraining protocols performed in downhill, uphill, and without inclination on the proteins related to hypertrophy signaling pathway in extensor digitorum longus (EDL) and soleus of C57BL/6 mice. We also performed histological and stereological analyses. Rodents were divided into control (CT; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up), and overtrained by running without inclination (OTR). The incremental load, exhaustive, and grip force tests were used as performance evaluation parameters. 36 h after the grip force test, EDL and soleus were removed and immediately used for immunoblotting analysis or stored at -80°C for histological and stereological analyses. For EDL, OTR/down decreased the protein kinase B (Akt) and tuberous sclerosis protein 2 (TSC2) phosphorylation (p), and increased myostatin, receptor-activated Smads (pSMAD2-3), and insulin receptor substrate-1 (pIRS-1; Ser307/636). OTR/down also presented low and high relative proportions of cytoplasm and connective tissue, respectively. OTR/up increased the mammalian target of rapamycin (pmTOR), 70-kDa ribosomal protein S6 kinase 1 (pS6K1) and pSMAD2-3, and decreased pTSC2. OTR decreased pTSC2 and increased pIRS-1 (Ser636). For soleus, OTR/down increased S6 ribosomal protein (pS6RP) and pSMAD2-3, and decreased pIRS-1 (Ser639). OTR/up decreased pS6K1, pS6RP and pIRS-1 (Ser639), and increased pTSC2 (Ser939), and pSMAD2-3. OTR increased pS6RP, 4E-binding protein-1 (p4E-BP1), pTSC2 (Ser939), and pSMAD2-3, and decreased pIRS-1 (Ser639). In summary, OTR/down inhibited the skeletal muscle hypertrophy with concomitant signs of atrophy in EDL. The effects of OTR/up and OTR depended on the analyzed skeletal muscle type. J. Cell. Physiol. 9999: 1-12, 2015. © 2015 Wiley Periodicals, Inc.

Efeito agudo do alongamento de diferentes grupos musculares no desempenho muscular de idosas

Among the numerous possibilities of physical exercise, it has been recommended that stretching routines should be incorporated into training programs focused on the elderly population, and that these routines should be preferentially performed on the same strength or aerobic training session. However, studies have shown that muscle strength production can be acutely impaired if it is preceded by static stretching exercises (AE). Although there seems to be a relationship between the number of stretched muscles and strength response, no studies were found examining such relationship in the same study, simultaneously. Thus, the objective of this study is to analyze the acute effect of stretching of different muscle groups on strength performance in older women. Nineteen physically active older women participated in the study (67.8 ± 5.3 years, 68.9 ± 12.4 kg, 157.2 ± 6.4 cm)-usar ponto final em inglês e não vírgula. The participants visited the lab for six consecutive days, three of which were intended to familiarization. Over the next three days, all the participants performed the experimental conditions: control; quadriceps stretching alone and complete stretching, involving the major extensors muscle groups of knees and hips. Both the two stretching conditions were realized with three series of 30s (total volume of 90 seconds for each exercise). All experimental conditions was be performed with an interval of at least 24 hours and order of execution was be randomized. The force transducer was connected to a leg press apparatus, where the isometric force time curve and electromyographic activity of the vastus medial and vastus lateralis were recorded. Measurements were registered immediately after each experimental condition, during five seconds. Statistical analysis comprised descriptive procedures and the One way ANOVA test for repeated measures (p<0.05). No statistically significant differences between the control and the two...

Análise de parâmetros neuromusculares e cinemáticos dos chutes Bandal Chagui e Dolhô Chagui do Taekwondo

Pós-graduação em Desenvolvimento Humano e Tecnologias - IBRC