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 the rowing and frontal-lateral cross, dumbbells exercises

The trapezius and serratus anterior muscles were studied in four modalities of rowing exercises executed with two grips, middle and closed, in comparison with the four different modalities of frontal-lateral cross, dumbbells exercise. It was used 24 male volunteers, 18 to 25 years old using a 2-channel TECA TE 4 electromyograph and Hewlett Packard surface electrodes. The results showed that TS acted in a higher significant way in all the modalities of rowing than in the supine lateral raise, inclined supine lateral raise and reverse supine lateral raise, dumbbells exercises, and demonstrated no standing frontal-lateral cross, dumbbells. The SI acted more significantly difference among all the execution modalities of rowing and the inclined supine lateral raise, dumbbells exercises than in all the rowing exercises; even though the activity levels do not make us suggest them as an excellent group of exercises for the development of this muscle.

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.

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.

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

Because the lack of specialized textbooks on the select and indication of basic exercises for physical conditioning programmes, an electromyographic study of the trapezius (upper portion) (TS) and the serratus anterior (lower portion) (SI) muscles in rowing exercises with middle and closed grip in three different modalities, upright, sitting and bent over was performed. 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 supine bench, a straight board and a 1,20 m-long bar made of light wood were used. The results showed that TS acted preferentially with closed grip sitting and bent over modalities, and presented no difference among the grips for upright rowing. SI acted preferentially with closed grip in all modalities, however, with activity levels that do not justify its indication for physical conditioning programmes.

Electromyographic validation of basic exercises for physical conditioning programmes IV. Analysis of the deltoid muscle (anterior portion) and pectoralis major muscle (clavicular portion) in frontal-lateral cross, dumbbells exercises

The electromyographic activity of the shoulder muscles deltoid - anterior portion (DA) and pectoralis major - clavicular portion (PMC) was tested on 24 male volunteers using a 2 channel TEC A TE4 electromyograph and Hewlett Packard surface electrodes during the execution of four different modalities of frontal-lateral cross, dumbbells exercises. The results showed that all of the tested exercises developed high levels of action potential for both muscles. So, we jusfity the indication of all of them for physical fitness programmes for DA and PMC. Some suggestions to the use of the tested exercises are presented.

Electromyographic validation of basic exercises for physical conditioning programmes V. The comparison of the response in the deltoid muscle (anterior portion) and the pectoralis major muscle (clavicular portion) determined by the frontal-lateral cross, dumbbells and the rowing exercises

The action potential level for shoulder muscles deltoid-anterior portion (DA) and pectoralis major-clavicular portion (PMC) determined by four different modalities of execution of rowing exercises, each one with two different grips, was recorded. These were compared with the action potential level determined for the same muscles by four different modalities of execution of the frontal-lateral cross, dumbbells exercises. Twenty-four male volunteers were examined using a 2 channel TECA TE4 electromyograph and Hewlett Packard surface electrodes. The statistic analysis showed significant (p<0,05) superiority for all the frontal-lateral cross, dumbbells exercises in comparison to all rowing exercises for the PMC, for the DA this generalized supremacy was not observed.

Influence of the application of juvenile hormone on the haemolymph total proteins and electrophoretic pattern of worker larvae of Apis mellifera

The aim of the present work was to verify the influence of the juvenile hormone (JH) applied on worker larvae of Apis mellifera 2 to 5 days old over the haemolymph total protein and electrophoretic pattern. Each larvae received topical applications of 1 ml of a solution of JH in hexane (1 μg/ml) on their 2 nd, 3 rd 4 th and 5 th day after hatching and had the amount and electrophoretic pattern of proteins from the haemolymph analyzed during the remaining days of their life. As a control, haemolymph of larvae of the same age that did not receive any kind of treatment was analyzed. The results show that the application of JH on larvae 3 or more days old affect the amount and electrophoretic pattern of the proteins, with this effect lasting through the subsequent days.

Electromyographic fatigue threshold of erector spinae muscle induced by a muscular endurance test in health men

Purpose: To identify the electromyographic fatigue threshold in the erector spinae muscle. Methods: Eight 19 to 24-year-old male volunteers participated in this study, in which surface electrodes were used, as well as a biological signals acquisition module (Lynx) with a sampling frequency of 1000Hz, a 1000 times gain, a 20Hz high pass filter and a 500Hz low pass filter. The test consisted of repeated isometric contractions of the erector spinae muscle in a 45° hip flexion posture, with 30%, 40%, 50% and 60% of the maximum voluntary isometric contraction. Results: A positive correlation of the RMS (root mean square) value as a function of time was found for most of the subjects with 40% (N = 6), 50% (N = 7) and 60% (N = 8) loads of the maximum voluntary isometric contraction. Conclusions: It was concluded, from this study, that the proposed protocol provides evidence, through the electromyographic signal, of the development of fatigue in the erector spinae muscle with loads of 40%, 50% and 60% of the maximum voluntary isometric contraction. The protocol also allows the electromyographic fatigue threshold and its probable applicability in the diagnosis of this phenomenon during repetitive activities to be determined.

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.

Electromyographic analysis of the arm muscles in front support exercises

The electromyographic activity of the biceps brachii - BB (long head), triceps brachii - TB (long head) and deltoideus - DA (clavicular portion) muscles, during the going (G) and return (R) phases in front support exercise, as well the efficacy of this exercise for the development of these muscles strength were studied in 10 male volunteers. The values were normalized through maximum voluntary isometric contraction (MVIC = 100%) and statistically analyzed using the Friedman, DMS and Wilcoxon non-parametric test. A value of p≤0.05 indicated significance (Campos, 1983). All the muscles presented higher electromyographic activity in the return phase of the movement. The triceps brachii was the muscle which had higher activity in both phases of the movement. It was concluded that the front support exercise is efficient for strength development mainly in the triceps brachii muscle.

Spatial pattern of parasitism in Diatraea saccharalis Fab. (Lep., Crambidae) populations at two different spatial scales in sugarcane fields in Brazil

The biological control of Diatraea saccharalis is regarded as one of the best examples of successful classical biological control in Brazil. Since the introduction of the exotic parasitoid, Cotesia flavipes, the decrease in D. saccharalis infestation in sugarcane fields has been attributed to the effectiveness of this agent. Native Tachinidae fly parasitoids (Lydella minense and Paratheresia claripalpis) have also been implicated in the success. Quantitative data confirming the actual contribution of these agents to the control of D. saccharalis are, however, rather scant. The purpose of this study was to investigate the spatial pattern of parasitism of these parasitoids in D. saccharalis populations at two large spatial scales (fields and zones). To investigate this subject, a large data set comprising information collected from a sugarcane mill located in the state of São Paulo, Brazil (São João sugarcane mill) was analysed. When regressions between the proportion parasitism against host density were computed, the percentage of significant regressions with either a positive or a negative slope was very small at both spatial scales for both parasitoid species. Regressing the densities of tachinid-parasitized hosts against host densities per field showed that these parasitoids presented a 'moderate aggregative' response to host densities, as 53.33% of the regressions were positively significant. Cotesia flavipes was 'weakly aggregated' on host densities at the field level, because only 33.33% of the regressions were positively significant. At the zone level, neither aggregative nor spatial proportion parasitism responses were evident for either parasitoid species due to the small percentage of significant regressions computed.

Electromyographic fatigue threshold of the biceps brachii muscle during dynamic contraction

The purpose of this study was to identify the Electromyographic Fatigue Threshold (EMG FT) of the biceps brachii muscle bilaterally during the elbow flexion in tests performed in different times: 30 second test, 1 minute test and fatiguing test, in concentric (CC) and eccentric (EC) phases. Nine healthy young men performed the elbow flexion with loads corresponding at 25%, 35% and 45% of the one repetition maximum (1-RM) in separate days. The results indicated that the test applied for the biceps brachii muscle during elbow flexion induced a progressive increment of EMG activity with time indicating muscle fatigue and allowed the identification of the EMG FT. The three tests presented no difference of EMG FT between CC and EC phases bilaterally.

Early healing pattern of autogenous bone grafts with and without e-PTFE membranes: A histomorphometric study in rats

Objective. The aim of this study was to perform quantitative and qualitative analyses of the initial repair pattern of an autogenous bone block graft when covered or not with e-PTFE membranes. Study design. Sixty male Wistar rats received a bone graft plus an e-PTFE membrane (MB) or just the graft (B). A block graft was harvested from the animal's calvarium and was laid and stabilized on the external cortical area near the angle of the mandible. Descriptive histology and histomorphometric analyses were carried out and the data were analyzed statistically by ANOVA and the Tukey test, with the level of significance set at 5%. Results. The results for group B showed that there was bone loss during the healing period (B0 = 1.38, B45 = 1.05, F = 7.91 > F C = 3.02), that is, the initial volume of the graft decreased in time. Bone tissue loss was about 24%. In contrast, the MB group showed bone tissue gain along the observation period (MB0 = 1.54, MB45 = 2.40, F = 7.91 > FC = 3.02), meaning that the total volume of newly formed bone was greater than the original graft area. Bone tissue gain was approximately 55%. MB showed significantly greater bone gain when compared to B (B45 = 1.05, MB45 = 2.40, F = 39.86 > FC = 1.90). These significant differences between B and MB could already be observed after 21 days. Conclusions. The bone block graft underwent resorption at an early healing stage, while additional new bone formation was observed when the bone graft was covered with an e-PTFE membrane. © 2005 Mosby, Inc. All rights reserved.