Analyse electromyographique des muscles levator scapulae et rhomboideus major dans les mouvements du membre superieur

The participation of the levator scapulae and rhomboideus major muscles in some movements of the upper limb was analysed in 21 young adult male volunteers. A 2 channel TECA TE4 electromyograph connected with single coaxial needle electrodes was used. In abduction, elevation, adduction, flexion and circumduction participation of both muscles in free movements of the upper limb was found. In extension, however, these muscles were inactive. In the same movements analysed with load, a major intensity of action of these muscles was registered as compared with those obtained in free movements.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles during respiration

The authors studied the trapezius (pars media) and rhomboideus major muscles during deep inspiration and expiration. The electromyographic records demonstrated that these muscles showed no activity in either phase of breathing.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 1)

The participation of the trapezius (pars media) and rhomboideus major muscles in free movements of abduction, adduction, flexion, extension and hyperextension of the arm was studied electromyographically. These muscles were active and synergic in all analysed movements, both acting with intensity that ranged from moderate to very marked.

Electromyographic study of the trapezius (pars media) and rhomboideus major muscles in movements of the arm (part 2)

The participation of the trapezius (pars media) and rhomboideus major muscles were studied electromyographically in movements of lateral and medial rotation (free and against resistance) of the arm. In the majority of cases both muscles were inactive during the performance of the analysed movements. Cases in which only one or both muscles acted in free rotation occurred only at the second half or ending of the movement. Records of electrical potentials during against resistance rotation were due to tensional efforts at the shoulder level.

Electromyographic study of the trapezius (pars superior) and levator scapulae muscles in circumduction and pendular oscillation of the arm

The trapezius (pars superior) and levator scapulae mm were studied in the arm movements of circumduction and pendular oscillation in 30 adult volunteers of both sexes. A two-channel TECA TE 4 electromyograph and single coaxial needle electrodes were used. It was found out that as arm conduction, both muscles show an activity that gradually increases and decreases the intensity at the elevation and lowering phases respectively. It was also noticed that between two consecutive circumductions a 'silent period' in the activity of the above mentioned muscles occurs. In pendular oscillation these muscles show electrical activity both in the forward and backward moving, and both muscles show a 'silent period' when the arm passes by the trunk. It was not observed in these movements any significant difference in activity of these muscles regarding sex.

Electromyographic study of the trapezius (pars superior) and levator scapulae muscles in the movements of the head

The electromyographic study of the trapezius (pars superior) and levator scapulae mm. in the head movements was carried out in 30 young, adult male volunteers of both sexes and with no antecedent muscular or articular problems. The analysis was carried out with a two-channel TECA TE4 electromyograph and with single coaxial needle electrodes. Inactivity of the trapezius (pars superior) and levator scapulae mm. was noticed in all cases, in flexion and extension movements, whereas in homolateral and heterolateral rotation movements, these muscles showed to be inactive in most cases.

Features of myoneural junctions in the extraocular muscles of the opossum (Didelphis albiventris)

The myoneural junctions present in the opossum (Didelphis albiventris) extraocular muscles were studied through histochemical and ultrastructural techniques. Three different types of junction were shown: two single types, 'en grappe' and 'en plaque', present in the middle third of the muscle fibers; and one multiple type, more rare and observed in the distal third of the muscle.

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

Electromyographic activity of the trapezius muscle and serratus anterior muscle was analysed in 24 male volunteers using a 2-channel TECA TE 4 electromyograp, during the execution of four different modalities of military press exercises with middle grip. The trapezius acted preferentially in the modalities standing press behind neck; and sitting forward and press behind neck, while SI did not show any significative difference among the modalities. The high levels of action potentials with which TS and SI acted justify the inclusion of these exercises in physical programmes.

Electromyographic validation of the trapezius and serratus anterior muscles in frontal-lateral cross, dumbbells exercises

Based on the lack of electromyographic researches on sport and programmes of physical conditioning, we can say that it is necessary to reexamine some exercises routinely used in the programmes of physical conditioning. Thus, the trapezius and serratus anterior muscles were studied electromyographically so that we could evaluate the validity in some ways of execution of the frontal-lateral cross, dumbbells exercises for the development of these muscles. We analyzed 24 male volunteers, 18 to 25 years old, using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. For the execution of the exercise it was used a supine bench, a straight board and two bars of 40 cm made of light wood. The results showed that TS acted preferentially in standing modality and in the inclined supine modality, however with activity levels that do not justify its inclusion in physical fitness programmes.

Electromyographic validation of the trapezius and serratus anterior muscles in rowing exercises with middle grip

Because the lack of textbooks based on electromyographic studies in the area of exercises for physical conditioning, the authors proposed to study the trapezius (upper portion) (TS) and the serratus anterior (lower portion) (SI) muscles during the execution of four different modalities of rowing exercises with middle grip in 24 male volunteers, 18 to 25 years old. For the recordings, it was used a two-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. For the movements, a supine bench and a 120 cm-long bar made of low weight wood were used. The results showed that TS acted significantly in upright, sitting and inclined rowing, justifying its inclusion in physical conditioning programmes, while SI, in spite of acting preferentially in upright and sitting rowing, presented activity levels which do not justify its inclusion.

Histoenzymology and morphometry of the masticatory muscles of tufted capuchin monkey (Cebus apella Linnaeus, 1758)

Samples of the anterior and posterior regions of the masseter and temporal muscles and of the anterior belly of the digastric muscle of 4 adult male tufted capuchin monkeys (Cebus apella) were removed and stained with HE and submitted to the m-ATPase reaction (with alkaline and acid preincubation) and to the NADH-TR and SDH reactions. The results of the histoenzymologic reactions were similar, except for acid reversal which did not occur in fibers of the fast glycolytic (FG) type in the mandibular locomotor muscles. FG fibers had a larger area and were more frequent in all regions studied. No significant differences in frequency or area of each fiber type were detected, considering the anterior and posterior regions of the masseter and temporal muscles. The frequency of fibers of the fast oxidative glycolytic (FOG) and slow oxidative (SO) types and of FOG area differed significantly between the anterior belly of the digastric muscle and the mandibular locomotor muscle. The predominance of fast twitch (FG and FOG) fibers and the multipenniform and bipenniform internal architecture of the masseter and temporal muscles, respectively, are characteristics that permit the powerful bite typical of tufted capuchin monkeys.

Electromyographic validation of the trapezius and serratus anterior muscles in rowing exercises with closed grip

Because the lack of specialized textbooks, the select of basic exercises for physical conditioning programmes is based on empirical knowledge. This fact led the authors to propose the study on electromyographic activity of the trapezius (upper portion) (TS) and the serratus anterior (lower portion) (SI) muscles in rowing exercises with closed grip in three different modalities. The tests were carried out with 24 male volunteers, 18 to 25 years old, by using a two-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. For exercises execution, a long bar made of light wood was used. TS acted significantly in the three different modalities, that is, upright, sitting and bent over, while SI acted preferentially in upright and sitting rowing exercises, justifying their inclusion as basic exercises in physical conditioning programmes.

Participation of the deltoid (anterior portion) and pectoralis major (clavicular portion) muscles in different modalities of supine and frontal elevation exercises with different grips

The muscles deltoid-anterior portion (DA) and pectoralis major-clavicular portion (PMC) were analysed to establish the muscular behavior and intensity patterns, as well to evaluate the connected participation of these muscles during supine and frontal elevation exercises. Twenty-four male volunteers were examined using a 2-channel TECA TE4 electromyograph and Hewlett Packard surface electrodes. Our results showed low levels of activity to PMC in frontal elevation exercises, whereas to DA the levels were very high. In the supine exercise, the action potential levels developed by the PMC were always lower than those presented by DA, however, with action simultaneity. Some suggestions to the use of the tested exercises are presented.

Electromyographic analysis of the pectoralis major and deltoideus anterior muscles in horizontal flyer exercises with loads

The effective activity of the pectoralis major and deltoideus anterior muscles in horizontal flyer exercises with external loads of 25, 50, 75 and 100% of the maximum load was studied in 11 male volunteers. The electromyographic analysis was done by using MEDI-TRACE-200 surface electrodes connected to a biological signal acquisition mode coupled to a PC/AT computer. The electromyographic signals were processed and the values obtained were normalized through maximum voluntary isometric contraction. It was statistically observed that in all types and loads of this exercise, the muscles presented significant differences in the concentric and eccentric phases. In the concentric phase, when different loads were compared, the muscles were more active with 75 and 100% of the maximum load, while in the eccentric phase, higher activity was observed with 100% of the maximum load. By analyzing each load effect in the concentric phase, it was verified that the muscles on the left side were more active than those on the right side with 25, 75 and 100% of the maximum load.