Pectoralis Major Research Articles

Transcriptomics reveals key genes responsible for functional diversity in pectoralis major muscles of native black Kadaknath and broiler chicken.

The online version contains supplementary material available at 10.1007/s13205-023-03682-0.

The Effectiveness Of The Combination Neck And Pectoralis Major Muscle Massage To Fluency Of Breast Milk Production On Post Partum Mothers

Breastfeeding is the optimal way to meet nutritional needs for infant growth, and is an ideal source of nutrition containing antibody substances to protect babies from various infections, viruses and fungi. Many failures in breastfeeding are caused by several factors, one of which is lack of breast milk production, maternal psychology and nutritional factors. Thus, it requires a method of knowledge about supporting techniques to facilitate breastfeeding in postpartum mothers. One of alternatives to facilitate breastfeeding is to do breast care using a method of combining neck massage and pectoralis major muscle massage. This study to determine the effect of combination of neck and pectoralis major muscle massage on the production of breast milk in postpartum mothers 1-3 days conducted at the Mandah Community Health Center. This Quasy experimental study used pre test and post design with control group. The population was all postpartum mothers at Mandah Community Health Center with a sample size of 20 taken by purposive sampling technique. The instrument was an observation on breast milk production. Data analysis using Mann Whitney testwith ap value of 0.003 <α 0.05, meaning that there was the effect of neck massage and pectoralis major muscle massage on the production of breast milk. There was the effect of the combination of neck massage and pectoralis major muscle massage on the production of breast milk in postpartum mothers 1-3 days. Midwives are expected to be able to disseminate and apply the combination method of neck massage and pectoralis major muscle massage as an alternative option to facilitate breastfeeding for postpartum mothers 1-3 days.

Mitochondrial dysfunction and calcium dyshomeostasis in the pectoralis major muscle of broiler chickens with wooden breast myopathy

The incidence of wooden breast (WB) meat of commercial broiler chicken has been increasing in recent years. Histological examination found that the occurrence of WB myopathy was accompanied by the pectoralis major (PM) muscle damage. So far, the potential mechanisms are not fully understood. This study aimed to explore the underlying mechanism of the damage of WB-affected PM muscle caused by changes in mitochondrial function, mitochondrial redox status and Ca2+ homeostasis. A total of 80 market-age Arbor Acres male broiler chickens were sampled and categorized into control (CON) and WB groups based on the evaluation of myopathic lesions. PM muscle samples were collected (n=8 in each group) for histopathological evaluation and biochemical analyses. Ultrastructural examination and histopathological changes suggested the occurrence of PM muscle damage in broiler chickens with WB myopathy. The WB group showed an increased level of reactive oxygen species and enhanced antioxidant capacities in mitochondria of PM muscle. These changes were related to impaired mitochondria morphology and mitochondrial dysfunction. In addition, abnormal expressions of Ca2+ channels led to substantial Ca2+ loss in SR and cytoplasmic Ca2+ overload, as well as Ca2+ accumulation in mitochondria, resulting in Ca2+ dyshomeostasis in PM muscle of broiler chickens with WB myopathy. Combined, these findings indicate that WB myopathy is related to mitochondrial dysfunction, mitochondrial redox status imbalance and Ca2+ dyshomeostasis, leading to WB-affected PM muscle damage.

Comparison of quantitative muscle ultrasound and whole-body muscle MRI in facioscapulohumeral muscular dystrophy type 1 patients

IntroductionMuscle ultrasound is a fast, non-invasive and cost-effective examination that can identify structural muscular changes by assessing muscle thickness and echointensity (EI) with a quantitative analysis (QMUS). To assess applicability and repeatability of QMUS, we evaluated patients with genetically confirmed facioscapulohumeral muscular dystrophy type 1 (FSHD1), comparing their muscle ultrasound characteristics with healthy controls and with those detected by MRI. We also evaluated relationships between QMUS and demographic and clinical characteristics.Materials and methodsThirteen patients were included in the study. Clinical assessment included MRC sum score, FSHD score and The Comprehensive Clinical Evaluation Form (CCEF). QMUS was performed with a linear transducer scanning bilaterally pectoralis major, deltoid, rectus femoris, tibialis anterior and semimembranosus muscles in patients and healthy subjects. For each muscle, we acquired three images, which were analysed calculating muscle EI by computer-assisted grey-scale analysis. QMUS analysis was compared with semiquantitative 1.5 T muscle MRI scale.ResultsAll muscles in FSHD patients showed a significant increased echogenicity compared to the homologous muscles in healthy subjects. Older subjects and patients with higher FSHD score presented increased muscle EI. Tibialis anterior MRC showed a significant inverse correlation with EI. Higher median EI was found in muscles with more severe MRI fat replacement.ConclusionsQMUS allows quantitative evaluation of muscle echogenicity, displaying a tight correlation with muscular alterations, clinical and MRI data. Although a confirmation on larger sample is needed, our research suggests a possible future application of QMUS in diagnosis and management of muscular disorders.

Pectus arcuatum: Description of a hybrid surgical technique

ObjetivesPectus Arcuatum (PA) is a very rare anterior chest wall deformity resulting from premature obliteration of the sternomanubrial junction. Unlike other chest wall deformities, surgical correction continues to be the only treatment option. We report our initial experience using the hybrid technique and evaluate the results. MethodsWe reviewed all the cases of PA that underwent a hybrid procedure between January 2020 and June 2022.We combined the Nuss procedure and the modified-Ravitch procedure. All patients underwent either percutaneous or thoracoscopic cryoanalgesia to improve postoperative pain management. The Nuss procedure was performed first. A single bar was inserted under thoracoscopic vision.Sternochondroplasty was performed through a 3-4-centimeter-long mid-sternal skin incision. After dissecting the sternal insertions of both pectoralis major muscles, bilateral subperichondrial chondrectomies were carried out and a wedge-shaped transverse sternal osteotomy was performed using an oscillating saw, preserving the posterior lamina. Sternal realignment was achieved by securing opposite sides of the osteotomy with two vertical titanium plates. ResultsThree patients with PA were subjected to the hybrid procedure between January 2019 and June 2022. The mean age was 15 years (14-16). No intraoperative complications were encountered. The mean operative time was 200 minutes. Postoperative radiography showed optimal sternal realignment and stabilization. Excellent esthetic results were obtained with high patient satisfaction in all cases. The overall hospital stay ranged from four to five days in all cases with optimal pain control. The mean follow-up was 26.6 months (6-38), recurrence was not noted after bar removal. ConclusionsThe simultaneous correction of the sternal depression, with the insertion of a single pectus bar, during the hybrid procedure enables surgeons to perform a less invasive sternochondroplasty and a single sternal wedge-osteotomy through a smaller and more esthetic mid-sternal skin incision, whilst maintaining chest-wall stability. The hybrid technique is a novel procedure that has been carried out successfully in the 3 cases reported in our study, with excellent esthetic results. To our knowledge cryoanalgesia has not been previously employed to better the postoperative pain management of patients undergoing surgical correction for PA.

Stiffness changes in internal rotation muscles of the shoulder and its influence on hemiplegic shoulder pain.

Hemiplegic shoulder pain (HSP) is a common complication in patients with stroke. The pathogenesis of HSP is complex, and muscle hypertonia, especially the hypertonia of internal rotation muscles of the shoulder, may be one of the important causes of shoulder pain. However, the relationship between muscle stiffness and HSP has not been well studied. The purpose of this study is to explore the correlations between the stiffness of internal rotation muscles and clinical symptoms in patients with HSP. A total of 20 HSP patients and 20 healthy controls were recruited for this study. The stiffness of internal rotation muscles was quantified using shear wave elastography, and Young's modulus (YM) of the pectoralis major (PM), anterior deltoid (AD), teres major ™, and latissimus dorsi (LD) were measured. Muscle hypertonia and pain intensity were evaluated using the Modified Ashworth Scale (MAS) and Visual Analog Scale (VAS), respectively. The mobility of the shoulder was evaluated using the Neer score. The correlations between muscle stiffness and the clinical scales were analyzed. YM of internal rotation muscles on the paretic side was higher than that of the control group in the resting and passive stretching positions (P < 0.05). YM of internal rotation muscles on the paretic side during passive stretching was significantly higher than that at rest (P < 0.05). YM of PM, TM, and LD during passive stretching were correlated with MAS (P < 0.05). In addition, the YM of TM during passive stretching was positively correlated with VAS and negatively correlated with the Neer score (P < 0.05). Increased stiffness of PM, TM, and LD was observed in patients with HSP. The stiffness of TM was associated with pain intensity of the shoulder and shoulder mobility.

Effects of a High-Volume 7-Week Pectoralis Muscle Stretching Training on Muscle Function and Muscle Stiffness

BackgroundThere is evidence that high-volume static stretching training of the lower limbs can increase the range of motion (ROM) while decreasing muscles stiffness. However, to date, there is no evidence on the effects of upper limb stretching training or its effect mechanism. Therefore, this study aimed to investigate the effects of a comprehensive 7-week static stretching training program of the pectoralis major muscle (PMa) on glenohumeral joint ROM, muscle force, and muscle stiffness.MethodsThirty-eight healthy, physically active participants (23 male, 15 female) were randomly assigned to either the PMa-static stretching intervention (PMa-SS) group or the control group. The PMa-SS group performed a 7-week intervention comprising three sessions a week for 15 min per session, including three static stretching exercises of the PMa for 5 min each. Before and after the intervention period, shoulder extension ROM, muscle stiffness of the PMa (pars clavicularis), and maximal voluntary isometric contraction (MVIC) peak torque (evaluated at both long (MVIClong) and short (MVICshort) muscle lengths) were investigated on a custom-made testing device at 45° shoulder abduction.ResultsIn the PMa-SS group, the shoulder extension ROM (+ 6%; p < 0.01; d = 0.92) and the MVIClong (+ 11%; p = 0.01; d = 0.76) increased. However, there were no significant changes in MVICshort or in PMa muscle stiffness in the PMa-SS group. In the control group, no changes occurred in any parameter.ConclusionIn addition to the increase in ROM, we also observed an improved MVIC at longer but not shorter muscle lengths. This potentially indicates an increase in fascicle length, and hence a likely increase in sarcomeres in series.

Reliable Location of Upper Extremity Lymphatic Channels for Use in Immediate Lymphatic Reconstruction.

Breast cancer-related lymphedema (BCRL) is a limiting sequelae of breast cancer treatment that may negatively impact 30% to 50% of high-risk breast cancer survivors. Risk factors for development of BCRL include axillary lymph node dissection (ALND), and recently, axillary reverse lymphatic mapping and immediate lymphovenous reconstruction (ILR) at time of ALND have been implemented to prevent BCRL. Reliable anatomy of neighboring venules has been commented on in the literature; however, little information exists about anatomical location of local lymphatic channels amenable for bypass. After institutional review board approval, patients who underwent ALND with axillary reverse lymphatic mapping and ILR at a tertiary cancer center from November 2021 to August 2022 were applicable for this study. The location and number of lymphatic channels used for ILR were identified and measured intraoperatively with the arm abducted to 90 degrees and soft tissue under no tension. Four measurements were taken to localize each lymphatic and were based on relationship with reliable anatomic landmarks including 4th rib, anterior axillary line, and lower border of the pectoralis major muscle. Demographics, oncologic treatments, intraoperative factors, and outcomes were prospectively maintained. Twenty-seven patients met inclusion for this study by August 2022 with a total of 86 lymphatic channels identified. Patients were on average 50 ± 12 years old with a body mass index of 30 ± 6 and had an average of 1 vein and 3 identifiable lymphatic channels amenable to bypass. Seventy percent of lymphatic channels were found in a cluster of 2 or more channels. The average horizontal location was 4.5 ± 1.4 cm lateral to the 4th rib. The average vertical location was 1.3 ± 0.9 cm from the superior border of the 4th rib. These data comment upon intraoperatively identified and consistent location of upper extremity lymphatic channels used for ILR. These lymphatic channels are often found in clusters with 2 or more lymphatic channels at the same location. Such insight may aid in easier intraoperative identification of amenable vessels for the unexperienced surgeon, decrease in intraoperative time, and higher success of ILR.

STERNALIS AN ANATOMICAL VARIANT – A CASE REPORT

The Sternalis muscle is an anatomical variant that lies superficial to Pectoralis major muscle and sternum. It has been recognised as a variant of Pectoralis major or Sternocleidomastoid usually (1). The worldwide prevalence has been stated as 6% (2). The present case discusses the anatomical and embryological relevance. Bilateral Sternalis muscle was found in a 60year old male during the routine cadaveric dissection for undergraduate students. The muscle flap if present, is clinically used for breast reconstruction surgery.

Effects of stepwise chilling with calcium incubation on proteolysis and tenderization in postmortem goose muscle

White Roman goose (12-wk-old male, N=30) carcasses were obtained from a local government-inspected slaughter plant at approximately ∼10-min postmortem. Each carcass was individually sealed in a zip-lock bag and chilled immediately in a water bath at 15°C for 1 h. Both sides of Pectoralis major muscles were excised from each carcass and incubated in 30 mM CaCl2 or 30 mM EDTA at 15°C for 5 h. After incubation, calcium-incubated and EDTA-incubated breast muscles were vacuum-packaged individually and stored at 5°C for 72 h. Control samples (without CaCl2 or EDTA incubation) were directly vacuum-packaged and chilled in a water bath at 15°C for 5 h and stored at 5°C for 72 h. Muscle specimens were taken from the left side of breast muscles at 1 h of chilling (∼1-h postmortem) and at 5 h of incubation at 15°C (∼6-h postmortem), as well as 24, 48, and 72 h of aging at 5°C for measuring the activities of calpain-1 and calpain-11 as well as the contents of 80 kDa calpain-1 subunit and desmin. The samples of shear force value and myofibril fragmentation index (MFI) were taken from the right side of breast muscle at 24 h and 72 h of 5°C storage. Our results showed that the decrease of the activities of calpain-1 and calpain-11 and the contents of 80 kDa calpain-1 subunit and desmin was more rapid (P < 0.05) in calcium-incubated samples than in control and EDTA-incubated samples. The shear force was lower, but the MFI was higher in calcium-incubated samples than in control and EDTA-incubated samples (P < 0.05). Therefore, our results suggest that the calpain-mediated proteolysis and tenderization in postmortem goose muscle could be greatly enhanced by combine effects of stepwise chilling with calcium incubation at 15°C and thereafter aging at 5°C. With applying this procedure, commercial slaughter plants may have an alternative way to improve the tenderness of goose meat.

Diagnostic value of high-frequency ultrasound for Poland syndrome.

The imaging diagnosis of Poland syndrome is mostly computed tomography (CT) or magnetic resonance imaging (MRI), whereas high-frequency ultrasound for the diagnosis of Poland syndrome is relatively rare. To investigate the diagnostic value of high-frequency ultrasound for Poland syndrome. A retrospective analysis of 15 patients diagnosed with Poland syndrome was performed, and the characteristics of ultrasound images were summarized. High-frequency ultrasound clearly depict the anatomical structures of each layer of the chest wall in patients with Poland syndrome. Ultrasonography mainly showed partial or total absence of the pectoralis major muscle on the affected side, and some of which were combined with the absence of the pectoralis minor muscle. The difference was statistically significant in the thickness of the affected chest wall compared with the healthy side (P < 0.01). Out of 15 cases with Poland syndrome, 11 were associated with ipsilateral brachydactyly or syndactyly, and high-frequency ultrasonography showed that the bifurcation position of the common palmar digital artery on the affected finger was lower than that on the healthy side. High-frequency ultrasound is an effective imaging method for the diagnosis of Poland syndrome.

Morphological variability of the pectoralis major muscle in human fetuses

BackgroundThe pectoralis major muscle is located in the anterior chest wall. In most cases, it is divided into clavicular, sternal (sternocostal) and abdominal heads. The aim of this study is to demonstrate and classify the morphological variability of the pectoralis major muscles in human fetuses. Material and methodsClassical anatomical dissection was performed on 35 human fetuses aged 18–38 weeks of gestation at death were examined. (17 female, and 18 male, 70 sides; fixed in 10% formalin solution). The fetuses were obtained from spontaneous abortion after informed consent of both parents and through deliberate donation to the Medical University anatomy program. Upon dissection, the following morphological features were assessed: the morphology of the pectoralis major, the possible occurrence of accessory heads, the possible absence of some head, and morphometric measurements of each head of the pectoralis major muscle. ResultsFive types of morphology (based on number of bellies) were observed in the fetuses. Type I was characterized by a single claviculosternal belly (10% of all samples). Type II comprised the clavicular and sternal heads (37.1%). Type III comprised three clavicular, sternal and abdominal heads (31.4%). Type IV (17.2%) was characterized by four muscle bellies and was divided into four subtypes. Type V (4.3%), was represented by five parts, and was divided into two subtypes. ConclusionsDue to its embryological development, the PM demonstrates great variability in the numbers of its parts. The most common type was the PM with two bellies, in line with previous studies which also distinguished only clavicular and sternal heads.

Myotonometry in Patients with Parkinson’s Disease: Assessment of Pre and Post Treatment through Comparisons with Healthy Controls

The study aims to assess the myotonometer parameters of major pectoralis, biceps brachialis, femoral biceps and anterior tibialis in patients with Parkinson’s disease before and after medical treatment using comparisons with healthy controls. A total of 49 patients with Parkinson’s disease (69.76 ± 6.39 years) and 42 healthy controls (60.48 ± 7.62 years) were tested using MyotonPRO before and one hour after drug administration. Five parameters were recorded (frequency [Hz], stiffness [N/m], decrement, relaxation [ms] and creep). At pre-treatment assessment, significantly increased values of myotonometer parameters were recorded for major pectoralis and biceps brachialis, with the exception of decrement. Frequency and decrement were significantly higher in patients’ femoral biceps and anterior tibialis. For all assessed muscles, frequency was significantly higher in Parkinson’s disease patients one hour after medication intake. Stiffness, relaxation and creep had increased values in major pectoralis. For the lower limb muscles, decrement had greater values. We concluded that there were no significant differences of major pectoralis and biceps brachialis elasticity between patients with Parkinson’s disease and healthy controls pre and post drug administration, with improved viscoelastic properties of biceps brachialis after medication. After drug administration, no significant differences of femoral biceps and anterior tibialis stiffness were noted between patients and controls.

Insignificant influence of the intertransverse process block for major breast cancer surgery: a randomized, blinded, placebo-controlled, clinical trial

IntroductionThe intertransverse process (ITP) block mimics the thoracic paravertebral block and allegedly ameliorates hemithoracic postoperative pain. However, concerning major reconstructive breast cancer surgery the modality has never been tested against...

Impact of dietary dandelion (Taraxacum mongolicum Hand. -Mazz.) supplementation on carcase traits, breast meat quality, muscle fatty and amino acid composition and antioxidant capacity in broiler chickens

This trial was performed to determine the effects of dietary supplementation of dry dandelion (Taraxacum mongolicum Hand. -Mazz.) on carcase traits, breast meat quality, muscle fatty and amino acid composition and antioxidant capacity of broiler chickens. A total of 120 Arbour Acres broiler chickens were randomly allotted to three groups and fed basal diet (CON), basal diet supplemented with 0.5 g/kg (LD) or 1.0 g/kg (HD) of dandelion. The results showed that compared with LD group, the eviscerated percentage of HD group tended to be higher (p = 0.090), while the abdominal fat yield tended to be lower (p = 0.078). In addition, dandelion quadratically increased redness, water loss rate, the proportion of C20:2, C20:4n-6, C22:6n-3 and the sum of n-3 PUFA and decreased cooking loss of Pectoralis major (PA) muscle (p < 0.05). The crude protein content of PA muscle showed a linear decrease trend with increasing dandelion levels (p = 0.057). The thiobarbituric acid reactive substance (TBARS) values on d 3 and d 5 were linearly and quadratically decreased (p < 0.05). The results indicated that dandelion could be used as natural antioxidant in broiler chickens’ diets to benefit meat quality and lipid oxidative stability. Highlights Dietary dandelion quadratically increased redness value and proportion of PUFA, while decreased cooking loss of Pectoralis major muscle. The thiobarbituric acid reactive substance values of Pectoralis major muscle on d 3 and d 5 were linearly and quadratically decreased by dietary dandelion supplementation. The beneficial effect of 0.5 g/kg of dandelion was superior to 1.0 g/kg.

Has the Pectoralis Major flap Really Become Obsolete?

To evaluate the current role of pectoralis major (PM) flap including the reasons for selecting it over free flaps. All patients who underwent PM flap at Apollo Hospitals Ahmedabad during the 3-year period from January 2020 to December 2022 were included. Patient demographics, tumour characteristics and complications were studied and reasons for selecting pectoralis major flap were analyzed. Data was entered in Microsoft excel spreadsheet and analyzed using online statistical calculators. The p value of < 0.05 was considered statistically significant. 57 patients underwent reconstruction with PM flap while 154 patients underwent free flap reconstruction. 54 were male and 3 were female. Median age was51 years. PM flap was used for intraoral lining in 25 patients, and it was bilobed in 26 patients with full thickness cheek defect. Most common complication was wound infection seen in 10 patients. 5 patients developed marginal necrosis of the flap and 5 had donor site wound dehiscence. No complete flap loss was seen. During the same period, 15/154 (9.74%) patients with free flaps developed complete flap necrosis and this was statistically significant (p = 0.012). Reasons for choosing PM flap were also analyzed. 14patients had major comorbidities, 18 had extensive disease, in 5 patients it was used for salvage post free flap failure, while 10 previously treated patients had unavailability of suitable vessels for anastomosis.12 patients underwent PM flap due to financial constraints. Thus, PM flap is not obsolete and continues to maintain its place in head and neck reconstruction.

In ovo probiotic supplementation promotes muscle growth and development in broiler embryos

In chickens, muscle development during embryonic growth is predominantly by myofiber hyperplasia. Following hatch, muscle growth primarily occurs via hypertrophy of the existing myofibers. Since myofiber number is set at hatch, production of more muscle fibers during embryonic growth would provide a greater myofiber number at hatch and potential for posthatch muscle growth by hypertrophy. Therefore, to improve performance in broilers, this study investigated the effect of in ovo spray application of probiotics on overall morphometry and muscle development in broiler embryos. For the study, fertile Ross 308 eggs were sprayed with different probiotics; Lactobacillus paracasei DUP 13076 (LP) and L. rhamnosus NRRL B 442 (LR) prior to and during incubation. The embryos were sacrificed on d 7, 10, 14, and 18 for embryo morphometry and pectoralis major muscle (PMM) sampling. Muscle sections were stained and imaged to quantify muscle fiber density (MFD), myofiber cross-sectional area (CSA), and nuclei density. Additionally, gene expression assays were performed to elucidate the effect of probiotics on myogenic genes. In ovo probiotic supplementation was found to significantly improve embryo weight, breast weight, and leg weight (P < 0.05). Further, histological analysis of PMM revealed a significant increase in MFD and nuclei number in the probiotic-treated embryos when compared to the control (P < 0.05). In 18-day-old broiler embryos, myofibers in the treatment group had a significantly smaller CSA (LP: 95.27 ± 3.28 μm2, LR: 178.84 ± 15.1 μm2) when compared to the control (211.41 ± 15.67 μm2). This decrease in CSA was found to be associated with a concomitant increase in MFD (fibers/mm2) in the LP (13,647 ± 482.15) and LR (13,957 ± 463.13) group when compared to the control (7,680 ± 406.78). Additionally, this increase in myofibrillar hyperplasia in the treatment groups was associated with upregulation in the expression of key genes regulating muscle growth including MYF5, MYOD, MYOG, and IGF-1. In summary, in ovo spray application of probiotics promoted overall embryo growth and muscle development in broilers.

Rupture of the Pectoralis Major: A Case Report

The rupture of the pectoralis major muscle is a rare entity. It occurs in young, healthy athletes during violent, eccentric contraction of the muscle with the arm held in an abducted and extended position, particularly in weightlifting. Diagnosis of pectoralis major tendon rupture can be made based on clinical examination but imaging plays a crucial role into confirming the diagnosis. Magnetic resonance imaging (MRI) is the most sensitive imaging modality for diagnosing, grading, evaluation and surgical planning of pectoralis major rupture. Early surgical treatment is associated with better outcome. We report a case of rupture of the pectoralis major in a 32-year-old man who presented a rupture of the pectoralis major after weight lifting.

Comparison of the Effects of Isometric Horizontal Abduction on Shoulder Muscle Activity During Wall Push-Up Plus and Wall Slide in Individuals With Scapular Winging.

Wall push-up plus (WPP) and wall slide (WS) are commonly prescribed in early rehabilitation to increase serratus anterior (SA) muscle activity. For individuals with scapular winging (SW), synergistic muscles such as upper trapezius (UT) and pectoralis major (PM) may compensate for weak SA during scapular movement. However, no studies have applied isometric horizontal abduction (IHA) during WS in individuals with SW nor have compared it with WPP with IHA. This study compared the effects of IHA on shoulder muscle activity during WPP and WS exercises in individuals with SW. Cross-sectional study; 2-way repeated-measures analysis of variance was used to assess the statistical significance of observed differences in SA, UT, PM, lower trapezius (LT), and infraspinatus (IS) muscle activities. Research laboratory. We recruited 30 individuals with SW comprising 20 men and 10 women. The individuals performed WPP and WS exercises with and without IHA using Thera-Band. Surface electromyography was used to measure muscle activity of the SA, UT, PM, LT, and IS during the isometric phase of WPP and WS. Maximal voluntary isometric contractions were recorded to normalize electromyographic data. There was no significant interaction between IHA application and exercise type for any of the shoulder muscles. IHA application increased SA (P = .008), UT (P = .001), LT (P = .009), and IS (P = .000) activities and decreased PM (P = .001) activity compared with those without IHA. WS exercises elicited higher PM (P = .017) and LT (P = .011) activities than WPP. WPP and WS with IHA may be effective in increasing the muscle activities of shoulder stabilizers and preventing overactivation of PM activity. WPP may be recommended for individuals with overactivated PM, whereas WS may be used to increase LT activity.

Avian mitochondria respiration is not predicated solely on complex abundance and DNA content

Skeletal muscle is a collection of heterogenous muscle fiber types differing in their ability to contract and metabolize energy substrates. The relative proportion of each fiber type in muscle drive function, where oxidative muscles are more fatigue resistant and generally have greater amounts of mitochondria than more glycolytic muscles that have less mitochondria because of their reliance on glycolytic reactions for energy production. However, even highly glycolytic muscles, like the breast muscle of chickens have mitochondria. Yet, differences in mitochondrial characteristics across muscle types remain largely unknown.We compared glycolytic and oxidative muscles of two different species in an attempt to understand better the relationship between mitochondrial DNA (mtDNA) and protein abundance, and mitochondria function. Glycolytic muscles longissimus lumborum (LL) and the pectoralis major (PM) and oxidative muscles masseter (MS) and quadriceps femoris (QF) were collected from adult pigs and chickens, respectively. Greater mtDNA abundance (2 -ΔΔCT ) was noted in oxidative muscles of both species compared to their glycolytic counterparts ( P &lt; 0.01). However, when absolute mtDNA was estimated, porcine MS had more mtDNA than LL ( P &lt; 0.001), whereas both avian muscles were equivalent. Porcine MS muscle had greater succinate dehydrogenase (SDHA, P &lt; 0.05) and citrate synthase (CS, P &lt; 0.001) than LL, while avian QF muscle had greater CS ( P &lt; 0.001) and voltage dependent anion channel (VDAC, P &lt; 0.05) compared to PM muscle. Isolated mitochondria from the MS of pigs had more electron transport chain complex I (CI, P &lt; 0.010) and complex II (CII, P &lt; 0.05) than those isolated from the LL. Avian mitochondria had no differences in either electron transport chain complexes across muscle, but mitochondria from the PM had greater VDAC than those purified from the QF. Oxygen consumption rates (OCR) followed muscle type, where mitochondria from oxidative muscles consumed more oxygen than those of glycolytic muscle when stimulated with ADP ( P &lt; 0.05). These data show that porcine mtDNA abundance, mitochondrial protein abundance, and mitochondrial function is greater in oxidative muscle compared to glycolytic muscle, and that respiration is greater in mitochondria from more oxidative muscle. However, differences in the relative abundance of mtDNA and electron transport chain complexes were not evident in isolated mitochondria from the chicken, yet respired differently nonetheless suggesting mtDNA and protein may not be directly correlated to the overall function of mitochondria. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.