Carcass characteristics, physicochemical traits, texture and microstructure of young and spent quails meat.

The purpose of the study was to compare young (6-wk-old) and spent (52-wk-old) Japanese quail in terms of body weight, carcass characteristics, and some meat quality traits. Whole carcasses were dissected, pectoral muscles and leg muscles were sampled for determination of basic chemical composition and L*a*b* color parameters, while m. pectoralis major was sampled for texture and microstructure traits. Age of quails had a significant effect on body weight, carcass weight, carcass yield, pectoral muscle, abdominal fat and skin with subcutaneous fat, and carcass remainders contents in eviscerated carcass. Spent quails had significantly higher intramuscular fat content in pectoral and leg muscles and protein content in breast muscle, and also lower content of water in breast and leg muscles than young quails. Slaughter age significantly affected lightness (L*) and redness (a*) of pectoral muscles, as well as texture traits (except for cohesiveness) and microstructure of m. pectoralis major, except for thickness of perimysium and endomysium. Regardless of age, quail sex had an effect on the carcass traits studied (except for leg muscle content), intramuscular fat content of pectoral and leg muscles, water content of leg muscles and yellowness of pectoral muscle. In addition, a significant effect of quail sex was found on cutting work, springiness, chewiness and marked microstructural characteristics, except for vertical fiber diameter. The interaction between age and sex was significant for most slaughter and microstructural characteristics and also WB-shear force of m. pectoralis major, and L*, b* pectoral muscles. Higher fatness of carcasses, higher intramuscular fat in meat, and poorer textural and microstructural characteristics of m. pectoralis major spent Japanese quail indicate poorer fulfillment of most consumers' requirements compared to carcasses and meat of young quails.

First transcriptomic insight into the working muscles of racing pigeons during a competition flight.

BACKGROUND: The currently known homing pigeon is a result of a sharp one-sided selection for flight characteristics focused on speed, endurance, and spatial orientation. This has led to extremely well-adapted athletic phenotypes in racing birds. METHODS: Here, we identify genes and pathways contributing to exercise adaptation in sport pigeons by applying next-generation transcriptome sequencing of m.pectoralis muscle samples, collected before and after a 300 km competition flight. RESULTS: The analysis of differentially expressed genes pictured the central role of pathways involved in fuel selection and muscle maintenance during flight, with a set of genes, in which variations may therefore be exploited for genetic improvement of the racing pigeon population towards specific categories of competition flights. CONCLUSIONS: The presented results are a background to understanding the genetic processes in the muscles of birds during flight and also are the starting point of further selection of genetic markers associated with racing performance in carrier pigeons.

Comparison of the Phenotypic Flexibility of Muscle and Body Condition of Migrant and Resident White-Crowned Sparrows.

AbstractSeasonally breeding birds express variations of traits (phenotypic flexibility) throughout their life history stages that represent adaptations to environmental conditions. Changes of body condition during migration have been well studied, whereas alterations of skeletal and cardiac muscles, body mass, and fat scores have yet to be characterized throughout the spring or fall migratory stages. Additionally, we examined flexible patterns of muscle, body mass, and fat score in migrant white-crowned sparrows (Zonotrichia leucophrys gambelii) in comparison with those in a resident subspecies (Zonotrichia leucophrys nuttalli) during the stages they share to evaluate the influence of different life histories. Migrants showed hypertrophy of the pectoralis muscle fiber area on the wintering grounds in late prealternate molt, yet increased pectoralis muscle mass was not detected until birds readied for spring departure. While pectoralis profile and fat scores enlarged at predeparture in spring and fall, pectoralis, cardiac, and body masses were greater only in spring stages, suggesting seasonal differences for migratory preparation. Gastrocnemius mass showed little change throughout all stages, whereas gastrocnemius fiber area declined steadily but rebounded in fall on the wintering grounds, where migrants become more sedentary. In general, residents are heavier birds with larger leg structures, while migrants sport longer wings and greater heart mass. Phenotypic flexibility was most prominent among residents with peaks of pectoralis, gastrocnemius, and body masses during the winter stage, when local weather is most severe. Thus, the subspecies express specific patterns of phenotypic flexibility with peaks coinciding with the stages of heightened energy demands: the winter stage for residents and the spring stages for migrants.

Comparative study of the quality of breast meat of free-range chicken (Gallus gallus domesticus) and conventional chicken (Gallus gallus).

This study compares the physicochemical characteristics of breast meat (Pectoralis major) from conventional chicken and free-range chicken production systems. Analyses of pH, instrumental color measurement, weight loss from cooking (WLC), and water retention capacity (WRC) were carried out. Average pH values were slightly higher for conventional chicken samples. WLC did not show a significant difference between conventional and free-range chicken samples. The WRC was better and higher for the free-range chicken samples than the conventional ones. The mean values for luminosity (L*) were within the normal range, with slightly higher values for conventional chicken. In chromatids a* and b*, there was a tendency towards a more reddish color for free-range chicken samples. The differences found for types of production can be explained mainly by the difference in age at slaughter, the degree of physical activity, animal feeding, among other characteristics that differentiate an animal raised by the extensive system from the intensive system.

Research Note: Chicken breast muscle satellite cell function: effect of expression of CNN1 and PHRF1.

The Wooden Breast myopathy results in the necrosis and fibrosis of breast muscle fibers in fast-growing heavy weight meat-type broiler chickens. Myogenic satellite cells are required to repair and regenerate the damaged muscle fibers. Using Genome Wide Association, candidate genes affected with Wooden Breast have been previously reported. The effect of these genes on satellite cell proliferation, differentiation, and the synthesis of lipids by satellite cells is unknown. Satellite cells isolated from the pectoralis major muscle from commercial Ross 708 broilers and a Randombred chicken (RBch) line were used. Expression of calponin 1 (CNN1) and PHD and ring fingers domains 1 (PHRF1) were knocked down by silent interfering RNA to determine their effect on satellite cell-mediated proliferation, differentiation, and lipid accumulation. CNN1 and PHRF1 affected satellite cell activity and lipid accumulation in both lines. Proliferation was reduced in the Ross 708 and RBch lines by knocking down the expression of both genes, and differentiation was affected with a line and treatment interaction when gene expression was reduced at the beginning of proliferation. During differentiation lipid accumulation was decreased with knocking down the expression of CNN1 and PHRF1. Both CNN1 and PHRF1 have not been reported previously in skeletal muscle and further research is required to determine their effect on satellite cell-mediated growth and regeneration of the pectoralis major (breast) muscle.

The Effect of Different Weight Plate Widths (Bumper vs. Standard) on the Biomechanics of the Bench Press.

ABSTRACT: Fiedler, MJ, Triplett, NT, Hamilton, KC, Needle, AR, and van Werkhoven, H. The effect of different weight plate widths (bumper vs. standard) on the biomechanics of the bench press. J Strength Cond Res 38(4): e143-e149, 2024-Anecdotal evidence suggests that bumper plates impact lifts in powerlifting and weightlifting differently than standard cast iron plates, but whether biomechanical differences exist between lifts using bumper versus standard plates has not been investigated. Eleven resistance-trained subjects performed the bench press at 70, 80, and 90% of their 1 repetition maximum (1RM) while being blinded to whether they were lifting with bumper or standard plates. Motion data were captured by an 8-camera motion capture system, and electromyography (EMG) data were recorded for the anterior deltoid, pectoralis major, and triceps brachii. Repeated-measures analysis of variances showed a significant main weight effect for time under tension (p < 0.001), total work (p < 0.001), and muscle activity through EMG (across all muscles; p < 0.001) and a significant weight × joint interaction effect for average joint moment (p < 0.001) and peak joint moment (p < 0.001). However, there were no significant differences observed between the different weight plates for any of the measures. The main finding of the study suggests that there are no biomechanical differences between using bumper plates compared with standard plates during the bench press lift.

Influence of 8-weeks of supervised static stretching or resistance training of pectoral major muscles on maximal strength, muscle thickness and range of motion.

OBJECTIVES: Current research suggests static stretch-induced maximal strength increases and muscle hypertrophy with potential to substitute resistance-training routines. However, most studies investigated the plantar flexors. This study explored the effects of a static stretching program on maximal strength, hypertrophy and flexibility of the pectoralis major and compared the effects with those of traditional resistance training. METHODS: Eighty-one (81) active participants were allocated to either a static stretching, strength-training or control group. Pectoralis stretching was applied 15 min/day, 4 days per week for 8 weeks, while resistance training trained 3 days per week, 5 × 12 repetitions. RESULTS: There was an increase in all parameters (strength: p < 0.001, ƞ2 = 0.313, muscle thickness: p < 0.001, ƞ2 = 0.157-0.264, flexibility: p < 0.001, ƞ2 = 0.316) and a time*group interaction (strength: p = 0.001, ƞ2 = 0.154, muscle thickness: p = 0.008-0.001, ƞ2 = 0.117-0.173, flexibility: p < 0.001, ƞ2 = 0.267). Post-hoc testing showed no difference between both intervention groups regarding maximal strength and muscle thickness (p = 0.905-0.983, d = 0.036-0.087), while flexibility increased in the stretching group (p = 0.001, d = 0.789). CONCLUSION: Stretching showed increases in maximal strength and hypertrophy, which were comparable with commonly used resistance training. Based on current literature, the influence of mechanical tension as the underlying mechanism is discussed. Furthermore, as equipment and comparatively long stretching durations are requested to induce meaningful strength increases in recreationally active participants, practical application seems limited to special circumstances.

Repetitions to failure increase pectoralis major activation with similar neuromuscular fatigue in trained men / Repetições até a falha aumentam a ativação do peitoral maior com similar fadiga neuromuscular em homens treinados

ABSTRACT Resistance training protocols performed to muscle failure (MF) have been employed in an attempt to maximize activation and neuromuscular fatigue. Therefore, the aim of this study was to compare the surface electromyography amplitude (EMGRMS) and frequency (EMGFREQ) of the pectoralis major between protocols performed to MF and non muscle failure (NMF). Seven trained men performed three sets at 60% of a repetition maximum, with a 3 min rest period and a 6s repetition duration. MF protocol was performing with maximum number of repetitions in all sets, while in NMF protocol subjects performed 6 repetitions in 3 sets. For data analysis two two-way repeated measures ANOVAs (Protocol x Repetition) were used and when necessary, Bonferroni post hoc was performed. The EMGRMS was higher in the protocol MF compare to NMF, but there was no difference in EMGFREQ between protocols. Although there were no significant differences in the frequency domain between protocols, perform repetitions to MF was a determining factor to generate higher amplitude of the electromyography signal. Thus, perform repetitions to MF could be considered an effective strategy to increase muscle activation in trained individuals, however, with similar neuromuscular fatigue.

RESUMO Protocolos de treinamento realizados até a falha muscular (FM) têm sido realizados na tentativa de maximizar a ativação e a fadiga neuromuscular. Portanto, o objetivo deste estudo foi comparar a amplitude do sinal eletromiografico (EMGRMS) e a frequência (EMGFREQ) do peitoral maior entre os protocolos realizados até a FM e sem falha muscular (SFM). Sete homens treinados realizaram três séries com 60% de uma repetição máxima, com um período de descanso de 3 min e uma duração da repetição de 6s. O protocolo FM foi realizado com o número máximo de repetições em todas as séries, enquanto no protocolo SFM os indivíduos realizaram 6 repetições em 3 séries. Para análise dos dados, foram utilizadas duas ANOVAs two-way com medidas repetidas (Protocolo x Repetição) e, quando necessário, foi realizado o post hoc de Bonferroni. Como resultado, a EMGRMS foi maior no protocolo FM comparado ao SFM, mas não houve diferença na EMGFREQ entre os protocolos. Embora não houvesse diferenças significativas no domínio da frequência entre os protocolos, a realização de repetições até a FM foi um fator determinante para gerar maior amplitude do sinal eletromiográfico. Assim, a realização de repetições até a FM pode ser considerada uma estratégia eficaz para aumentar a ativação muscular em indivíduos treinados, porém com fadiga neuromuscular semelhante.

Comparison of shoulder and trunk muscle activation between different pullover exercises / Comparación de la activación de los músculos del hombro y del tronco entre diferentes ejercicios de pullover

OBJECTIVE: To quantify and compare the electromyographic activity of trunk and upper limb muscles in three different pullover exercises. METHODS: 15 healthy men, with at least two years of experience in resistance training, executed in random order six repetitions with 60% of 1 Maximum Repetition for three different pullover exercises: lying on a step with a barbell, grip 100% biacromial (E1); lying on a step with a barbell, grip 150% (E2); lying on a Swiss ball with a barbell, grip 100% (E3). Surface electromyography was recorded from the Deltoideus (Clavicular and Spinalis Pars), Pectoralis Major (Clavicular and Sternocostalis Pars), Serratus Anterior, Triceps Brachii (Long Head), Latissimus Dorsi, Infraspinatus, Rectus Abdominis, Obliquus Internus Abdominis and Transversus Abdominis. The normalized electromyogram of maximal voluntary isometric contraction of each muscle was calculated for each exercise. RESULTS: The most engaged muscles were Infraspinatus (51-53% Electromyogram maximal voluntary isometric contraction) and Posterior Deltoid (49-51% Electromyogram maximal voluntary isometric contraction). Surface electromyography activity was similar between the E1, E2 and E3 exercises. CONCLUSIONS: This study quantified muscular solicitation during pullover exercises performed with 60% Maximum Repetition. The muscles with higher level of activation were the Posterior Deltoid and the Infraspinatus, suggesting that pullover may be a valid option for strengthening the dynamic stabilizing muscles of shoulder joint in trained individuals. No significant differences in muscle electromyography intensity were observed when grip distance and trunk stabilization were altered, showing that these conditions do not influence muscle activation levels. However, the 1 Maximum Repetition was lower when the pullover was performed on a Swiss ball, suggesting that it is possible to obtain higher level of muscle recruitment with lower weights in unstable exercises

OBJETIVO: cuantificar y comparar la actividad electromiográfica de diez músculos en tres diferentes ejercicios de pullover. MÉTODO: 15 hombres sanos, con al menos dos años de experiencia en entrenamiento de resistencia, realizaron seis repeticiones al 60% de 1 Repetición Máxima en orden aleatorio para tres ejercicios de pullover diferentes: acostados en una tabla con mancuernas y agarre 100% biacromial (E1), acostados en una tabla con mancuernas, agarre 150% biacromial (E2) y acostado en una pelota suiza con mancuernas, agarre 100% biacromial (E3). Se registró la señal electromiográfica de superfície de Deltoides (anterior y posterior), Pectoral Mayor (clavicular y esternocostal), Serrato Anterior, Tríceps Braquial (porción externa), Dorsal Grande, Infraespinoso, Recto Abdominal, Oblicuo Interno y Transverso del Abdominal. Se calculó la Repetición Máxima para normalizar la señal electromiográfica de cada músculo y para cada ejercicio. RESULTADOS: los músculos más involucrados fueron el Infraespinoso (51-53% señal electromiográfica de superfície 1 Repetición Máxima) y el Deltoides Posterior (49-51% señal electromiográfica de superfície 1 Repetición Máxima). La actividad electromiográfica de superficie fue similar entre los ejercicios E1, E2 y E3. CONCLUSIONES: este estudio cuantificó las demandas musculares durante los ejercicios pullover realizados con un 60% de la Repetición Máxima. Los músculos con mayor nivel de activación fueron el Deltoides Posterior e Infraespinoso, lo que sugiere que el pullover puede ser una opción válida para fortalecer los músculos estabilizadores dinámicos de la articulación del hombro en individuos entrenados. No se observaron diferencias significativas en el nivel de la activación muscular cuando se modificó la distancia del agarre y la estabilización del tronco, lo que demuestra que estas condiciones no influyen en los niveles de activación muscular. Sin embargo, 1 Repetición Máxima fue menor cuando el pullover se realizó en una pelota suiza, lo que sugiere que es posible obtener un mayor nivel de reclutamiento muscular con pesos menores en ejercicios inestables

Abnormal origin of posterior circumflex humeral artery and subscapular artery: case report and review of the literature / Origem anômala das artérias circunflexa posterior do úmero e subescapular: relato de caso e revisão de literatura

The subscapular, anterior circumflex, and posterior circumflex arteries arise from the third part of the axillary artery. During dissection of the right upper limb of the cadaver of a 70-year-old male, a common trunk was observed arising from the third part of the axillary artery which, after traveling for 0.5 cm, bifurcated into subscapular and posterior circumflex humeral arteries. The common trunk was crossed anteriorly by the radial nerve. The medial nerve was formed by medial and lateral roots on the medial side of the third part of the axillary artery, remaining medial to the brachial artery up to the cubital fossa and then following its usual course thereafter. Awareness of the vascular variations observed in the present case is important when conducting surgical procedures in the axilla, for radiologists interpreting angiographs, and for anatomy-pathologists studying rare findings

As artérias subescapular, circunflexa anterior e circunflexa posterior se originam da terceira parte da artéria axilar. Durante a dissecção de membro superior direito de um cadáver humano com 70 anos de idade, do sexo masculino, um tronco comum foi observado originando-se da terceira parte da artéria axilar, após um percurso de 0,5 cm, bifurcando-se em artéria subescapular e artéria circunflexa posterior do húmero. O tronco comum era cruzado anteriormente pelo nervo radial. O nervo medial era formado por raízes medial e lateral, no lado medial da terceira parte da artéria axilar, permanecendo em posição medial à artéria braquial até a fossa cubital e seguindo seu curso usual a partir de então. Conhecimento das variações vasculares observadas neste caso é importante ao executar procedimentos cirúrgicos na axila, para radiologistas que interpretam radiografias, e também para anatomo-patologistas que estudam achados raros

Comparison of electromyographic activity during the bench press and barbell pullover exercises / Comparação da atividade eletromiográfica entre os exercícios supino horizontal e pull-over na barra / Comparación de la actividad electromiografíca entre los ejercicios press de banca horizontal y pull-over barra

The aim of the study was to compare the electromyographic (EMG) activity of the following muscles: clavicular portion of pectoralis major, sternal portion of pectoralis major, long portion of triceps brachii, anterior deltoid, posterior deltoid and latissimus dorsi during dynamic contractions between flat horizontal bench press and barbell pullover exercises. The sample comprised 12 males individuals experienced in resistance training. The volunteers made three visits to the laboratory. The first one consisted of 12 repetitions of the exercises for the electromyographic data collection. The results showed a higher EMG activation of the pectoralis major and anterior deltoid muscles in the flat horizontal bench press in comparison with the barbell pullover. The triceps brachii and latissimus dorsi muscles were more activated in the barbell pullover...

O objetivo do estudo foi comparar a atividade eletromiográfica dos músculos peitoral maior porção clavicular, peitoral maior porção externa, porção longa do tríceps braquial, deltóide anterior, deltóide posterior e grande dorsal durante contrações dinâmicas entre os exercícios supino horizontal e pull-over. A amostra foi composta por 12 indivíduos do sexo masculino experientes em treinamento resistido. Os voluntários fizeram três visitas ao laboratório; a primeira consistiu na avaliação antropométrica e no teste de 1RM em ambos os exercícios, e a segunda e terceira consistiram na realização de 12 repetições para a coleta dos dados da eletromiografia. Após a análise dos resultados foi possível identificar uma ativação eletromiográfica superior dos músculos peitoral maior e deltóide anterior no supino horizontal em relação ao pull-over barra. Já as musculaturas do tríceps braquial e grande dorsal foram mais ativadas no pull-over barra...

El objetivo del estudio fue comparar la actividad electromiografíca de los músculos pectoral mayor en la porción clavicular, pectoral mayor porción esternal, porción larga del tríceps braquial, deltoides anterior, deltoides posterior y dorsal ancho durante las contracciones dinámicas entre los ejercicios press de banca y pullover. Hicieron parte de la muestra 12 individuos del sexo masculino expertos en el entrenamiento con pesas. Los voluntarios hicieran tres visitas al laboratorio, la primera, consistió en la evaluación antropométrica y en el teste de 1RM en los dos ejercicios, y la segunda y tercera, consistió en la realización de 12 repeticiones para la recolecta de los datos de la electromiografía. Después del análisis de los resultados fue posible identificar una activación electromiografíca superior en las porciones del musculo pectoral mayor y en el deltoides anterior en el press de banca horizontal en relación al pull-over barra. Ya las musculaturas del tríceps braquial y del dorsal ancho fueron las más activadas en el pull-over barra...

Electromyographic assessment of trunk and shoulder muscles during a Pilates pull-up exercise / Avaliação eletromiográfica de músculos do tronco e do ombro durante um exercício Pilates de pull-up / Evaluación electromiográfica de los músculos del tronco y del hombro durante un ejercicio Pilates de pull-up

This study compares surface electromyographic activity of the internal oblique, rectus abdominis, multifidus, iliocostalis, anterior deltoids during the pull-up on a lower and on a higher difficulty level. We assessed nine adults with previous experience in Pilates. The root mean square (RMS) values were normalized by maximum isometric contraction for each participant. During the ascent phase, the low spring position showed a significantly higher RMS than the high spring position of 8.9% for deltoid, 17.2% for internal oblique, 22.3% for rectus abdominis, 4.1% for iliocostalis, and 5.6% for multifidus, and in the descent phase, the RMS in the lower spring exceeded significantly the high spring position in 1.6% for the deltoid, 10% for internal oblique, 31.4% for rectus abdominis and 11.4% for iliocostalis. There was no predominance of abdominal muscles over the shoulder muscle in any spring position. The pull-up exercise can be a useful choice for the core and anterior deltoid muscles strengthening...

Este estudo compara a atividade eletromiográfica de superfície dos músculos oblíquo interno, reto abdominal, multífidos, iliocostal e deltóide anterior durante o pull-up em dois níveis de dificuldade (mola alta e mola baixa). Foram avaliadas nove adultos com experiência anterior em Pilates. Os valores RMS foram normalizados pela contração isométrica máxima. Durante a fase de subida, a posição de mola baixa mostrou RMS significativamente maiores em relação a alta de 8,9% para deltóide, 17,2% para o oblíquo interno, 22,3% para o reto abdominal, 4,1% para iliocostal, e 5,6% para o multífido, e na fase de descida, em 1,6% para o deltóide, 10% para oblíquo interno, 31,4% para o reto abdominal e 11,4% para o iliocostal. Não houve predomínio dos músculos abdominais sob o músculo do ombro em qualquer posição de mola. O exercício de pull-up pode ser ferramenta útil para o fortalecimento da musculatura do core e do músculo deltóide anterior...

Este estudio compara la EMG superficial de los músculos recto del abdomen, oblicuo interno, multifidos, ilio-costal y deltoides anterior durante el ejercicio pull-up en dos niveles de dificultad. Se evaluaron a nueve adultos experimentados en Pilates. Los valores de RMS se normalizaron por la contracción isométrica máxima. Durante la fase de ascenso, la posición baja del resorte mostró valores significativamente majores de RMS que la posición alta de 8,9% para lo deltoides, 17,2% para oblicuo interno, 22,3% para recto abdominal, 4,1% para ilio-costalis, y 5,6% para multifidos. En la fase de descenso, el RMS, en el muelle inferior, excede significativamente la posición alta del resorte en 1,6% para el deltoides, 10% para oblicuo interno, 31,4% para recto abdominal y 11,4% para ilio-costalis. No hubo predominio de los músculos abdominales bajo los deltoides anteriores. Pull-up puede ser una herramienta útil para el trabajo del core y para la fortificación del deltoides anterior...

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

The deltoid (anterior portion) and pectoralis major (clavicular portion) were evaluated in several execution ways of military press exercises with open and middle grips in order to know their behavior pattern. It was analyzed 24 male volunteers, using a 2-channel TECA TE4 electromyograph and Hewllet Packard surface electrodes. It was observed that the execution variation with open and middle grips does not present any significant difference as for the demanding level neither for the pectoralis major muscle nor the deltoid muscle.

Isokinetic muscle assessment after treatment of pectoralis major muscle rupture using surgical or non-surgical procedures

INTRODUCTION: Rupture of the pectoralis major muscle appears to be increasing in athletes. However, the optimal treatment strategy has not yet been established. OBJECTIVES: To compare the isokinetic shoulder performance after surgical treatment to that after non-surgical treatment for pectoralis major muscle rupture. METHODS: We assessed 33 pectoralis major muscle ruptures (18 treated non-surgically and 15 treated surgically). Horizontal abduction and adduction as well as external and internal rotation at 60 and 120 degrees/s were tested in both upper limbs. Peak torque, total work, contralateral deficiency, and the peak torque agonist-to-antagonist ratio were measured. RESULTS: Contralateral muscular deficiency did not differ between the surgical and non-surgical treatment modalities. However, the surgical group presented twice the number of athletes with clinically acceptable contralateral deficiency (<20 percent) for internal rotators compared to the non-surgical group. The peak torque ratio between the external and internal rotator muscles revealed a similar deficit of the external rotation in both groups and on both sides (surgical, 61.60 percent and 57.80 percent and non-surgical, 62.06 percent and 54.06 percent, for the dominant and non-dominant sides, respectively). The peak torque ratio revealed that the horizontal adduction muscles on the injured side showed similar weakness in both groups (surgical, 86.27 percent; non-surgical, 98.61 percent). CONCLUSIONS: This study included the largest single series of athletes reported to date for this type of injury. A comparative analysis of muscular strength and balance showed no differences between the treatment modalities for pectoralis major muscle rupture. However, the number of significant clinical deficiencies was lower in the surgical group than in the non-surgical group, and both treatment modalities require greater attention to the rehabilitation process, especially for the recovery of muscle strength and balance.

Randomized clinical trial on the preservation of the medial pectoral nerve following mastectomy due to breast cancer: impact on upper limb rehabilitation / Estudo clínico aleatório sobre a preservação do nervo peitoral medial em mastectomia por câncer de mama: impacto na reabilitação do membro superior

CONTEXT AND OBJECTIVE: Systematic modifications to the surgical technique of mastectomy have been proposed with the objective of minimizing injuries to the pectoral nerves and their effects. The aim of this study was to compare muscle strength and mass of the pectoralis major muscle (PMM) and abduction and flexion of the homolateral upper limb following mastectomy among women with breast cancer undergoing either preservation or sectioning of the medial pectoral nerve (MPN). DESIGN AND SETTING: Randomized, double-blind, clinical trial on 30 women with breast cancer who underwent mastectomy between July 2002 and May 2003 in Campinas, Brazil. METHODS: The women were allocated to a group, in which the MPN was preserved, or to another group in which it was sectioned. Fisher's exact and Wilcoxon tests were used to analyze the data, along with Friedman and ANOVA analysis of variance. RESULTS: In the MPN preserved group, 81 percent of the women did not lose any PMM strength, compared with 31 percent in the sectioned MPN group (confidence interval, CI = 1.21; relative risk, RR = 2.14; P < 0.03). There were no differences between the groups regarding muscle mass (CI = 0.32; RR = 0.89; P = 0.8), shoulder abduction (CI = 1.36; RR = 0.89; P = 0.28) and shoulder flexion (CI = 1.36; RR = 1.93; P = 0.8). CONCLUSIONS: Preservation of the MPN was significantly associated with maintenance of PMM strength, compared with nerve sectioning. No differences in muscle mass or in abduction and flexion of the homolateral shoulder were found between the groups. CLINICAL TRIAL REGISTRATION NUMBER: ANZCTR - 00082622

CONTEXTO E OBJETIVO: Modificações sistemáticas técnica cirúrgica das mastectomias têm sido propostas com o objetivo de minimizar lesões dos nervos peitorais e seus efeitos. O objetivo deste artigo foi comparar força e trofismo do músculo peitoral maior (MPM) e amplitude de movimento do membro superior, homolaterais à mastectomia em mulheres com carcinoma de mama submetidas à preservação ou não do nervo peitoral medial (NPM). TIPO DE ESTUDO E LOCAL: Ensaio clínico aleatório, duplo-cego, com 30 mulheres com carcinoma de mama submetidas a mastectomias entre julho de 2002 e maio de 2003, em Campinas, Brasil. MÉTODOS: As mulheres foram alocadas em um grupo em que o NPM foi preservado e em outro no qual o NPM foi seccionado. Para análise de dados, foram utilizados os testes exato de Fisher e Wilcoxon, além das análises de variância de Friedman e Anova (análise de variância). RESULTADOS: No grupo com NPM preservado, 81 por cento das mulheres não sofreram perda de força do MPM comparado a 31 por cento no outro grupo (intervalo de confiança, IC = 1.21 e risco relativo, RR = 2.14, P < 0,03). Em relação a trofismo muscular (IC = 0.32 e RR = 0.89, P = 0.8), a abdução (IC = 1.36, RR = 0.89, P = 0.28) e flexão (IC = 1.36, RR = 1.93 e P = 0.8) do ombro homolateral, não houve diferenças entre os grupos. CONCLUSÃO: A preservação do MPM foi significativamente associada a manutenção da força do MPM comparada com a secção do nervo. Não foram encontradas diferenças no trofismo muscular ou na amplitude de movimento do ombro entre os grupos. REGISTRO DE ENSAIO CLÍNICO NÚMERO: ANZCTR - 00082622

Respuesta diafragmática en función de la actividad previa del músculo / Diaphragmatic response is influenced by previous muscle activity

OBJETIVO: La actividad previa puede modificar la contractilidadmuscular, lo que puede conducir a la infra o supraestimaciónde la fuerza en las determinaciones funcionales.El presente trabajo se ha propuesto como objetivovalorar cambios en la presión máxima generada por el diafragmatras diferentes series de contracciones isométricasespontáneas y cuasi máximas.MÉTODOS: Se estudiaron por duplicado 6 perros con unpeso medio ± desviación estándar de 26 ± 7 kg. Se obtuvo larespuesta supramáxima del diafragma –presiones gástrica(Pgatw) y esofágica (Pestw) inducidas por estimulación frénicabilateral, y acortamiento muscular (sonomicrometría)— porestimulación simultánea supramáxima de ambos nervios frénicos,tanto en situación basal como tras series cortas(5), medianas (10) y largas (20) de esfuerzos inspiratorios espontáneoscontra la vía aérea ocluida, antes y después de administraranestesia subaracnoidea (elimina la contribuciónventilatoria de los músculos intercostales).RESULTADOS: La serie corta y, sobre todo, la serie medianaprovocaron la potenciación de la respuesta contráctil (Pgatwde 3,2 ± 0,4 a 3,7 ± 0,3, y de 3,5 ± 0,3 a 3,9 ± 0,3 cmH2O, respectivamente;p < 0,05 ambas). La potenciación fue algo superiorcon anestesia subaracnoidea (un 21 frente al 11% sinanestesia, para la Pgatw tras las series medianas). La serielarga provocó, sin embargo, una disminución de la respuesta(Pgatw: 3,2 ± 0,4 a 2,5 ± 0,3 cmH2O; p < 0,05), probablementepor predominio de la fatiga sobre la potenciación.CONCLUSIONES: Los esfuerzos previos determinan la capacidadcontráctil del diafragma y resulta difícil predecir elpredominio de fatiga o de potenciación en la respuesta. Estefactor debería tenerse en cuenta al determinar las presionesrespiratorias máximas en la clínica diaria

OBJECTIVE: Previous muscle activity can alter musclecontractility and lead to strength underestimation oroverestimation in functional measurements. The objectiveof this study was to evaluate changes in the maximumpressure produced by the diaphragm after different seriesof spontaneous near-to-maximal isometric contractions.METHODS: Duplicate studies were performed on 6 dogs witha mean (SD) weight of 26 (7) kg. The supramaximal responseof the diaphragm was achieved by simultaneous supramaximalstimulation of both phrenic nerves, both under basal conditionsand after series of 5, 10, and 20 spontaneous inspiratory effortsagainst the occluded airway, performed before and after spinalanesthesia (which eliminates the ventilatory contribution of theintercostal muscles). The response was measured using thetwitch gastric pressure (Pga) and twitch esophageal pressure(Pes) and by muscle shortening (sonomicrometry).RESULTS: The short series of 5 inspiratory efforts and, inparticular, the medium series of 10 efforts produced potentiationof the contractile response, with a rise in the Pga from 3.2 (0.4)cmH2O to 3.7 (0.3) cmH2O, and from 3.5 (0.3) cmH2O to 3.9 (0.3)cmH2O, respectively (P=.05 in both cases). The potentiation wassomewhat greater after subarachnoid anesthesia (an increase inthe Pga of 21% after the medium series of 10 efforts withanesthesia vs 11% without anesthesia). However, the long seriesof 20 efforts produced a fall in the response, with a decrease in thePga from 3.2 (0.4) cmH2O to 2.5 (0.3) cmH2O (P<.05), probablydue to fatigue overcoming the effect of potentiation.CONCLUSIONS: Previous effort affects the contractilecapacity of the diaphragm and it is difficult to predict thepredominance of fatigue or potentiation in the response. Thisfactor must be taken into account when determining themaximum respiratory pressures in daily clinical practice

Determinação de perfil de repetições máximas no exercício de extensão de pernas e supino reto com diferentes percentuais de força / Determination of the profile of maximum repetitions in the leg extension exercise and straight supino with different percentages of strength

Os objetives desse estudo foram verificar se tabelas de força padrões são praticáveis, se há diferença entre o número de repetições máximas (RM) intra-exercício e entre grupamentos musculares, para a mesma intensidade. A amostra compõe-se de 20 indivíduos do sexo masculino, entre 17 e 30 anos. Foram aplicados testes de carga, máxima e RM, para o grupo muscular peitoral e quadríceps. A análise estatística foi realizada ao nível de significância de até P=0,05. Os resultados do exercício supino reto (SR) comparados a cadeira extensora (CE), apresentou diferença estatística para a intensidade 80% (P<0,05). Os resultados da CE foram superiores aos do SR, exceto para intensidade de 50%. A análise intra-exercício apresentou diferença estatística (P<0,05) no supino reto em diferentes percentuais de força. Para a CE não houve diferença estatística para as intensidades 60-70 % e 70-80 %. As tabelas analisadas se mostraram sem padronização de valores, com enormes variações de valores entre as diversas tabelas e no número de repetições entre membro superior e inferior. Concluise que diferentes faixas de força proporcionam diferenças no número de RM, entre indivíduos e entre grupamento muscular. As limitações destas tabelas padrões evidenciam a importância de programas de treinamento de força de forma individualizada.

The objectives of this study was to verify if the standard force tables are practicable, if there is difference between the number of maximum repetitions (RM) intra-exercise and between muscular groups, for the same intensity. The sample is composed by 20 individuals of the masculine sex, between 17 and 30 years. Load tests, maximum and RM were applied, for the pectoral muscular group and quadriceps. The statistics analysis was carried through to the level of significance P=0,05. The straight supine year-end results (MR.) compared the extensive chair (CE), presented statistic difference for intensity 80% (P<0,05). The results of the CE were superior to the ones of MR., except for 50% intensity. The intra-exercise analysis presented statistic difference (P<0,05) in the straight supine in different percentages of strength. For the CE there was not statistic difference for the intensities 60-70% and 70-80%. The analyzed tables were shown without standardization of values, with enormous variations of values between diverse tables and the number of repetitions between upper/lower member. One concludes that different bands of strength pr vide differences in the RM number, between individuals andmuscular grouping. The limitations of these standard tables evidence the importance of individualized strength programs.

Pectoralis minor muscle. An unusual insertion

Variations in the insertion of the pectoralis minor muscle have been described. Although much of them were considered to be functionally normal, others may be associated in certain with disconfort related to shoulder movement. Here we described a bilateral, symmetric insertional variation of the pectoralis minor muscle that was found during a routine dissection of upper limbs. In this variation, the tendon crossed the superior surface of the coracoid process to insert on the major tubercle of the humerus head, where it fused with the tendon of the supraspinatus muscle. This variation could be the cause of pain during certain shoulder movements as a result of neurovascular compression, and may lead to mechanical alterations in the muscular dynamics of the shoulder.

Estudo eletromiográfico dos músculos peitoral maior serrátil anterior e grande dorsal em movimentos de remo a seco / Electromyographic study of the pectoralis major, serratus anterior and latissimus dorsi muscles in shoulder joint during simulated row movements

Os músuculos peitoral maior, serrátil anterior e grande dorsal foram analisados eletromiograficamente, em movimentos simulados de remo. Utilizou-se um aparelho TECA TE 2-7 de quatro canais e eletrodos de superfície, em 15 indivíduos voluntários, adultos jovens, previamente exercitados em movimentos de remo. Na fase de arranco, o peitoral maior e o grande dorsal säo os músculos que exibem maior atividade; no movimento de volta à frente, o mais ativo é o serrátil anterior