Muscle and joint mechanics during maximum force biting following total temporomandibular joint replacement surgery.

Total temporomandibular joint replacement (TMJR) surgery is the established treatment for severe temporomandibular joint disorders. While TMJR surgery is known to increase mouth-opening capacity, reduce pain and improve quality of life, little is known about post-surgical jaw function during activities of daily living such as biting and chewing. The aim of this study was to use subject-specific 3D bite force measurements to evaluate the magnitude and direction of joint loading in unilateral total TMJR patients and compare these data to those in healthy control subjects. An optoelectronic tracking system was used to measure jaw kinematics while biting a rubber sample for 5 unilateral total TMJR patients and 8 controls. Finite element simulations driven by the measured kinematics were employed to calculate the resultant bite force generated when compressing the rubber between teeth during biting tasks. Subject-specific musculoskeletal models were subsequently used to calculate muscle and TMJ loading. Unilateral total TMJR patients generated a bite force of 249.6 ± 24.4 N and 164.2 ± 62.3 N when biting on the contralateral and ipsilateral molars, respectively. In contrast, controls generated a bite force of 317.1 ± 206.6 N. Unilateral total TMJR patients biting on the contralateral molars had a significantly higher lateral TMJ force direction (median difference: 63.6°, p = 0.028) and a significantly lower ratio of working TMJ force to bite force (median difference: 0.17, p = 0.049) than controls. Results of this study may guide TMJ prosthesis design and evaluation of dental implants.

Cut-off points to determine muscle mass reduction by electrical bioimpedance analysis for the diagnosis of sarcopenia in older adults: a systematic review

Introduction: Sarcopenia is considered a muscular disease known in older adults, characterized by the reduction of muscle mass and physical performance. In 2010, the European Working Group on Sarcopenia in Older People(EWGSOP) established criteria to define sarcopenia based on muscle mass, grip strength, and gait speed. Bioelectrical Impedance Analysis (BIA) has become popular for estimating body composition in various populations, particularly for assessing sarcopenia in geriatrics. Objective: To identify the cutoff points for Skeletal Muscle Mass Index (SMI) using BIA for the diagnosis of sarcopenia inmen and women aged over 60 years within the period between January 1, 2010, and July 19, 2020. Methodology: A literature search was conducted in the databases of PubMed, Science Direct, Springer, EBSCO, Scopus, OVID, and WOS. Studies in English and Spanish reporting cutoff points for skeletal muscle mass evaluated byBIA for the diagnosis of sarcopenia in adults > 60 years ofboth sexes were included. Results: Only 14 studies met the inclusion criteria. The cutoff points for the decrease in muscle mass varied in each study from 7 kg/m2 to ≤ 10.75 kg/m2 inmen and from <5.7 kg/m2 to <7.4 kg/m2 in women, adjusted for height. Conclusion: This systematic review enabled the recognition of distinct cutoff points for the diagnosis of sarcopenia in older adults world wide. Further more, it demonstrated that the cut off points for SMI vary from country to country. As a result, further studies encompassing diverse regions within each country are necessary to establish cutoff points that enhance the accurate diagnosis of sarcopenia in the elderly population (AU)

The Intramuscular Circulation Is Affected by Neck and Shoulder Pain.

The purpose of this study was to investigate the effects of neck and shoulder pain (NSP) and the position of the head and neck on the intramuscular circulation of the cervical muscles such as the trapezius and levator scapulae muscles in young females. Ten NSP subjects (mean age: 20.9 ± 0.5 years) and ten non-NSP subjects (mean age: 20.6 ± 0.7 years) were recruited to this study. Near-infrared spectroscopy (NIRS) was used to non-invasively measure total haemoglobin (Total-Hb), oxygenated haemoglobin (Oxy-Hb), and deoxygenated haemoglobin (Deoxy-Hb) of the trapezius and levator scapulae muscles. The measurements of Total-Hb, Oxy-Hb, and Deoxy-Hb were taken in the neutral position, immediately after the maximally flexed (extended) position, and after 30 s in the maximally flexed (extended) position. In flexion, no significant main effect or interaction was observed with Total-Hb and Oxy-Hb. A significant interaction was observed with Deoxy-Hb (p < 0.01). There was no significant difference in the changes over time in the NSP group (p = 0.91). However, in the non-NSP group, a significant increase was noted at the neutral position to immediately after the maximally flexed position (p < 0.01) and at the end of maintaining the maximally flexed position (p < 0.01). In extension, no significant main effect or interaction was observed with Total-Hb and Oxy-Hb. A significant interaction was observed with Deoxy-Hb (p < 0.01). In the NSP group, no significant difference was observed in the changes over time (p = 0.91). In the non-NSP group, however, a significant decrease was observed from the neutral position to immediately after the maximally extended position (p < 0.01). The results of this study indicate that maintaining either maximal cervical flexion or extension may affect venous blood flow on non-NSP group. However, no effect on NSP group was observed due to existing diminished intramuscular circulation.

The role of osteocalcin in regulation of glycolipid metabolism and muscle function in children with osteogenesis imperfecta.

Objective: Osteoblasts are discovered to secrete hormones with endocrine effects on metabolism, and osteocalcin (OC) is the most abundant non-collagenous protein in bone. We investigate the relationship between serum OC levels and glycolipid metabolism and muscle function in children with osteogenesis imperfecta (OI). Methods: A total of 225 children with OI and 80 healthy controls matched in age and gender were included in this single center study. Serum levels of fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C, HDL-C) were measured by automated analyzers. Serum levels of fasting insulin (FINS) were measured using an automated electrochemiluminescence system. Serum levels of OC and undercarboxylated osteocalcin (ucOC) were measured by enzyme-linked immunosorbent assay. Grip strength and timed-up-and-go (TUG) test were measured. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry. Results: OI patients had significantly higher body mass index (BMI), FBG, and HOMA-IR, but lower HDL-C levels, lower grip strength and longer TUG than control group (all P<0.05). Serum OC, ucOC levels, and ucOC/OC in OI type III patients were significantly lower than those in OI patients with type I and IV. Serum levels of OC, ucOC, and ucOC/OC were negatively correlated to BMI, FBG, insulin levels, and HOMA-IR (all P<0.05). The ratio of ucOC/OC was positively correlated to grip strength (r=0.512, P=0.036), lean mass percentage (%LM) of the total body and limbs, and negatively correlated to fat mass percentage (%FM) of the total body, %FM and fat mass index (FMI) of the trunk (all P<0.05). Conclusions: Obesity, glucolipid metabolic abnormalities, and reduced grip strength were common in children with OI. Circulating osteocalcin and ucOC may play an important role in the regulation of glucose metabolism, as well as the muscle function of children with OI.

A growth factor-expressing macrophage subpopulation orchestrates regenerative inflammation via GDF-15.

Muscle regeneration is the result of the concerted action of multiple cell types driven by the temporarily controlled phenotype switches of infiltrating monocyte-derived macrophages. Pro-inflammatory macrophages transition into a phenotype that drives tissue repair through the production of effectors such as growth factors. This orchestrated sequence of regenerative inflammatory events, which we termed regeneration-promoting program (RPP), is essential for proper repair. However, it is not well understood how specialized repair-macrophage identity develops in the RPP at the transcriptional level and how induced macrophage-derived factors coordinate tissue repair. Gene expression kinetics-based clustering of blood circulating Ly6Chigh, infiltrating inflammatory Ly6Chigh, and reparative Ly6Clow macrophages, isolated from injured muscle, identified the TGF-ß superfamily member, GDF-15, as a component of the RPP. Myeloid GDF-15 is required for proper muscle regeneration following acute sterile injury, as revealed by gain- and loss-of-function studies. Mechanistically, GDF-15 acts both on proliferating myoblasts and on muscle-infiltrating myeloid cells. Epigenomic analyses of upstream regulators of Gdf15 expression identified that it is under the control of nuclear receptors RXR/PPARγ. Finally, immune single-cell RNA-seq profiling revealed that Gdf15 is coexpressed with other known muscle regeneration-associated growth factors, and their expression is limited to a unique subpopulation of repair-type macrophages (growth factor-expressing macrophages [GFEMs]).

Mitochondrial Dysfunction in Cancer Cachexia: Impact on Muscle Health and Regeneration.

Cancer cachexia is a frequently neglected debilitating syndrome that, beyond representing a primary cause of death and cancer therapy failure, negatively impacts on patients' quality of life. Given the complexity of its multisystemic pathogenesis, affecting several organs beyond the skeletal muscle, defining an effective therapeutic approach has failed so far. Revamped attention of the scientific community working on cancer cachexia has focused on mitochondrial alterations occurring in the skeletal muscle as potential triggers of the complex metabolic derangements, eventually leading to hypercatabolism and tissue wasting. Mitochondrial dysfunction may be simplistically viewed as a cause of energy failure, thus inducing protein catabolism as a compensatory mechanism; however, other peculiar cachexia features may depend on mitochondria. On the one side, chemotherapy also impacts on muscle mitochondrial function while, on the other side, muscle-impaired regeneration may result from insufficient energy production from damaged mitochondria. Boosting mitochondrial function could thus improve the energetic status and chemotherapy tolerance, and relieve the myogenic process in cancer cachexia. In the present work, a focused review of the available literature on mitochondrial dysfunction in cancer cachexia is presented along with preliminary data dissecting the potential role of stimulating mitochondrial biogenesis via PGC-1α overexpression in distinct aspects of cancer-induced muscle wasting.

Collagen-derived dipeptide Pro-Hyp administration accelerates muscle regenerative healing accompanied by less scarring after wounding on the abdominal wall in mice.

Collagens act as cellular scaffolds in extracellular matrixes, and their breakdown products may also have important biological functions. We hypothesize that collagen dipeptide Pro-Hyp induces favorable healing activities and examined the effects of Pro-Hyp administered via different routes on wound healing using our novel murine model, in which an advanced fibrosis-prone scar lesion was developed in the abdominal muscle wall under the skin. After excising a part of the abdominal wall, a free-drinking experiment was performed using solutions with casein (CS), high molecular weight collagen peptides (HP), and low molecular weight collagen peptides including Pro-Hyp and Hyp-Gly (LP), in addition to water (HO). On day 21 of the study, when compared to the HO and CS groups, muscle regeneration in the LP group was significantly advanced in the granulation tissue, which was associated with a decrease in fibrosis. To clarify the effects of Pro-Hyp, daily intraperitoneal administration of pure Pro-Hyp was performed. Pro-Hyp administration induced many myogenically differentiated cells, including myogenin-positive myoblasts and myoglobin-positive myocytes, to migrate in the granulation tissue, while scar tissue decreased. These results indicated that Pro-Hyp administration accelerates muscle regenerative healing accompanied by less scarring after wounding on the abdominal wall.

Is "Delayed Onset Muscle Soreness" a False Friend? The Potential Implication of the Fascial Connective Tissue in Post-Exercise Discomfort.

Strenuous and unaccustomed exercise frequently lead to what has been coined "delayed onset muscle soreness" (DOMS). As implied by this term, it has been proposed that the associated pain and stiffness stem from micro-lesions, inflammation, or metabolite accumulation within the skeletal muscle. However, recent research points towards a strong involvement of the connective tissue. First, according to anatomical studies, the deep fascia displays an intimate structural relationship with the underlying skeletal muscle and may therefore be damaged during excessive loading. Second, histological and experimental studies suggest a rich supply of algogenic nociceptors whose stimulation evokes stronger pain responses than muscle irritation. Taken together, the findings support the hypothesis that DOMS originates in the muscle-associated connective tissue rather than in the muscle itself. Sports and fitness professionals designing exercise programs should hence consider fascia-oriented methods and techniques (e.g., foam rolling, collagen supplementation) when aiming to treat or prevent DOMS.

Low lean mass is associated with lower urinary tract symptoms in US men from the 2005-2006 national health and nutrition examination survey dataset.

We investigated the relationship between low lean mass (LLM) and lower urinary tract symptoms (LUTS) using the 2005-2006 National Health and Nutrition Examination Survey (NHANES) dataset. We enrolled 959 men with an average age of 52.08 ± 7.91 years and performed weighted multiple regression analysis to determine the independent relationship between exposure variables (LLM, alternate LLM) and outcomes variables (urinary hesitancy, incomplete emptying, urinary frequency, nocturia, daytime LUTS, clinical LUTS) after adjusting for confounding factors. The prevalence of urinary hesitancy (OR = 7.76, P < 0.0001), incomplete emptying (OR = 2.49, P = 0.0070), urinary frequency (OR = 3.28, P < 0.0001), daytime LUTS (OR = 3.88, P < 0.0001) and clinical LUTS (OR = 8.11, P < 0.0001) was significantly higher among men with LLM compared to men without LLM. Moreover, alternate LLM (ALLM) was positively associated with urinary hesitancy (OR = 17.97, P < 0.0001), incomplete emptying (OR = 4.68, P = 0.0003), daytime LUTS (OR = 2.47, P = 0.0136) and clinical LUTS (OR = 12.18, P < 0.0001). These findings demonstrate that both LLM and ALLM were associated with a higher risk of LUTS in men aged ≥ 40 years, which suggested that early management and treatment of lean mass loss may improve or alleviate LUTS.

Coordination of tumor growth and host wasting by tumor-derived Upd3.

yki-induced gut tumors in Drosophila are associated with host wasting, including muscle dysfunction, lipid loss, and hyperglycemia, a condition reminiscent of human cancer cachexia. We previously used this model to identify tumor-derived ligands that contribute to host wasting. To identify additional molecular networks involved in host-tumor interactions, we develop PathON, a web-based tool analyzing the major signaling pathways in Drosophila, and uncover the Upd3/Jak/Stat axis as an important modulator. We find that yki-gut tumors secrete Upd3 to promote self-overproliferation and enhance Jak/Stat signaling in host organs to cause wasting, including muscle dysfunction, lipid loss, and hyperglycemia. We further reveal that Upd3/Jak/Stat signaling in the host organs directly triggers the expression of ImpL2, an antagonistic binding protein for insulin-like peptides, to impair insulin signaling and energy balance. Altogether, our results demonstrate that yki-gut tumors produce a Jak/Stat pathway ligand, Upd3, that regulates both self-growth and host wasting.

The Prevalence and Association of Stress Urinary Incontinence, Core Muscle Endurance, and Low Back Pain among Married Women in Saudi Arabia: A Case-Control Study.

PURPOSE: There may be a strong association among stress urinary incontinence (SUI), low back pain (LBP), and core muscle endurance (CME) in married women. This study is aimed at evaluating the prevalence and clinical association between SUI, CME, and LBP among married women in Saudi Arabia. METHODS: The study was based on a case-control research design, conducted among 143 women with LBP (mean age, 32 ± 7.4 years) and 160 healthy women (mean age, 31.7 ± 6.7 years). SUI, CME, and functional disability were assessed using the international consultation on the Incontinence Questionnaire-Short Form (ICIQ-SF), prone plank test (PP), and Oswestry Disability Index for LBP-United Arab Emirates edition (ODI-UAE). RESULTS: The prevalence of SUI was found to be 60% in the LBP group while 20% in the control group. CME revealed a stronger negative correlation with SUI in the LBP group (r s = -0.75) than in the control group (r s = -0.63). CONCLUSIONS: The prevalence of SUI was observed higher in women with LBP than healthy women. CME exhibited a stronger association with SUI than LBP among women with LBP compared to healthy women in Saudi Arabia. Therefore, the role of CME in SUI development or vice versa among married women with LBP may be subjected to further research.

Pathophysiological Effects of Overactive STIM1 on Murine Muscle Function and Structure.

Store-operated Ca2+ entry (SOCE) is a ubiquitous mechanism regulating extracellular Ca2+ entry to control a multitude of Ca2+-dependent signaling pathways and cellular processes. SOCE relies on the concerted activity of the reticular Ca2+ sensor STIM1 and the plasma membrane Ca2+ channel ORAI1, and dysfunctions of these key factors result in human pathologies. STIM1 and ORAI1 gain-of-function (GoF) mutations induce excessive Ca2+ influx through SOCE over-activation, and cause tubular aggregate myopathy (TAM) and Stormorken syndrome (STRMK), two overlapping disorders characterized by muscle weakness and additional multi-systemic signs affecting growth, platelets, spleen, skin, and intellectual abilities. In order to investigate the pathophysiological effect of overactive SOCE on muscle function and structure, we combined transcriptomics with morphological and functional studies on a TAM/STRMK mouse model. Muscles from Stim1R304W/+ mice displayed aberrant expression profiles of genes implicated in Ca2+ handling and excitation-contraction coupling (ECC), and in vivo investigations evidenced delayed muscle contraction and relaxation kinetics. We also identified signs of reticular stress and abnormal mitochondrial activity, and histological and respirometric analyses on muscle samples revealed enhanced myofiber degeneration associated with reduced mitochondrial respiration. Taken together, we uncovered a molecular disease signature and deciphered the pathomechanism underlying the functional and structural muscle anomalies characterizing TAM/STRMK.

Curcumin and Resveratrol Improve Muscle Function and Structure through Attenuation of Proteolytic Markers in Experimental Cancer-Induced Cachexia.

Muscle wasting and cachexia are prominent comorbidities in cancer. Treatment with polyphenolic compounds may partly revert muscle wasting. We hypothesized that treatment with curcumin or resveratrol in cancer cachectic mice may improve muscle phenotype and total body weight through attenuation of several proteolytic and signaling mechanisms in limb muscles. In gastrocnemius and soleus muscles of cancer cachectic mice (LP07 adenocarcinoma cells, N = 10/group): (1) LC-induced cachexia, (2) LC-cachexia+curcumin, and (3) LC-cachexia + resveratrol, muscle structure and damage (including blood troponin I), sirtuin-1, proteolytic markers, and signaling pathways (NF-κB and FoxO3) were explored (immunohistochemistry and immunoblotting). Compared to nontreated cachectic mice, in LC-cachexia + curcumin and LC-cachexia + resveratrol groups, body and muscle weights (gastrocnemius), limb muscle strength, muscle damage, and myofiber cross-sectional area improved, and in both muscles, sirtuin-1 increased, while proteolysis (troponin I), proteolytic markers, and signaling pathways were attenuated. Curcumin and resveratrol elicited beneficial effects on fast- and slow-twitch limb muscle phenotypes in cachectic mice through sirtuin-1 activation, attenuation of atrophy signaling pathways, and proteolysis in cancer cachectic mice. These findings have future therapeutic implications as these natural compounds, separately or in combination, may be used in clinical settings of muscle mass loss and dysfunction including cancer cachexia.

Effect of physical therapy intervention on thickness and ratio of the sternocleidomastoid muscle and head rotation angle in infants with congenital muscular torticollis: A randomized clinical trial (CONSORT).

BACKGROUND: Early diagnosis as well as treatment is important in management of congenital muscular torticollis (CMT). The purpose of this study was to find an effective physical therapy modality to improve the sternocleidomastoid (SCM) muscle thickness, the ratio of the SCM muscle thickness on the affected side to that on the non-affected side (A/N ratio), and head rotation in infant under 3 months of age diagnosed with CMT. METHODS AND ANALYSIS: A single-blind, randomized clinical trial was conducted. Participants were assigned in one of the 3 study groups through randomization. The treatment was performed 3 times a week for 30 minutes until the head tilt was ≤5 degrees. Group 1 was treated by handling for active or active-assist movement, group 2 was treated with passive stretching, and group 3 was treated with thermotherapy. For general characteristics, a χ2 test and 1-way analysis of variance were used. Intragroup differences were analyzed using a paired t test, and intergroup differences were analyzed using an age-adjusted analysis of covariance. RESULTS: After the intervention, there was no significant difference between groups in terms of SCM thickness on the affected side and A/N ratio (P > .05). Degree of head rotation on the affected side showed significant differences between groups (P < .05), with Group 2 showing significantly better results than group 1 and group 3 (P < .05, both). CONCLUSION: Passive stretching treatment was more effective than other treatments of this study for improvement in degree of head rotation in CMT infants under 3 months of age. TRIAL REGISTRATION: The trial is registered at the Institutional Review Board of Sahmyook University (IRB number, 2-7001793-AB-N-012019103HR) and the Clinical Research Information Service (CRiS; registry number, KCT0004862).

Analysis of ultrasound image biological image algorithm in the restoration of muscle group movement function / Análise do algoritmo de imagem biológica por ultrassom na restauração da função de movimento do grupo muscular / Análisis del algoritmo de imágenes biológicas de imágenes de ultrasonido en la restauración de la función de movimiento del grupo muscular

ABSTRACT Objective: By studying the recognition effect of ultrasonic biological image data analysis on muscle group motion function, the evaluation value and significance of ultrasonic biomedical image combination algorithm on muscle group motion function are discussed. Methods: A Gabor filtering algorithm is proposed to smooth the original image. The MVEF algorithm is used to enhance the ultrasonic image and binary further the image again. Using the principle of the Hove transform, the thickness of the muscle is automatically estimated. Results: The square of correlation coefficients of the manual measurement method, Gabor filtering algorithm and MVEF algorithm are 91.3%, 91.3% and 87.8%, respectively. The difference between the manual measurement and the estimation based on the Gabor filtering algorithm is 1.45 ± 0.48mm. The difference between the results of manual measurement and the MVEF algorithm is 1.38 ± 0.56mm. The computation time of the MVEF algorithm and Gabor algorithm are 5 seconds and 0.3 seconds, respectively. Conclusions: The algorithm proposed in this study can effectively measure the muscle thickness, fast, convenient and accurate, and can reflect the contractility of skeletal muscle well, which is of great value for the recognition and evaluation of muscle group movement function. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Objetivo: Ao estudar o efeito de reconhecimento da análise de dados de imagem biológica ultrassônica na função de movimento do grupo muscular, o valor de avaliação e a importância do algoritmo de combinação de imagem biomédica ultrassônica na função de movimento do grupo muscular são discutidos. Métodos: Um algoritmo de filtragem Gabor é proposto para suavizar a imagem original. O algoritmo MVEF é usado para aprimorar ainda mais a imagem ultrassônica e binar a imagem novamente. Usando o princípio da transformada de H ove, a espessura do músculo é automaticamente estimada. Resultados: O quadrado dos coeficientes de correlação do método de medição manual, algoritmo de filtragem Gabor e algoritmo MVEF são 91,3%, 91,3% e 87,8%, respectivamente. A diferença entre a medição manual e a estimativa baseada no algoritmo de filtragem Gabor é 1,45 ± 0,48 mm. A diferença entre os resultados da medição manual e o algoritmo MVEF é de 1,38 ± 0,56 mm. O tempo de cálculo do algoritmo MVEF e do algoritmo Gabor é de 5 segundos e 0,3 segundos, respectivamente. Conclusões: O algoritmo proposto neste estudo pode medir efetivamente a espessura muscular, de forma rápida, conveniente e precisa, e pode refletir bem a contratilidade do músculo esquelético, o que é de grande valor para o reconhecimento e avaliação da função de movimento do grupo muscular. Nível de evidência II; Estudos terapêuticos- investigação dos resultados do tratamento.

RESUMEN Objetivo: Al estudiar el efecto de reconocimiento del análisis de datos de imágenes biológicas ultrasónicas sobre la función del movimiento del grupo muscular, se discuten el valor de evaluación y la importancia del algoritmo de combinación de imágenes biomédicas ultrasónicas sobre la función del movimiento del grupo muscular. Métodos: Se propone un algoritmo de filtrado de Gabor para suavizar la imagen original. El algoritmo MVEF se utiliza para mejorar aún más la imagen ultrasónica y volver a binar la imagen. Utilizando el principio de la transformada de H ove, el grosor del músculo se estima automáticamente. Resultados: El cuadrado de los coeficientes de correlación del método de medición manual, el algoritmo de filtrado de Gabor y el algoritmo MVEF son 91,3%, 91,3% y 87,8%, respectivamente. La diferencia entre la medición manual y la estimación basada en el algoritmo de filtrado de Gabor es de 1,45 ± 0,48 mm. La diferencia entre los resultados de la medición manual y el algoritmo MVEF es 1,38 ± 0,56 mm. El tiempo de cálculo del algoritmo MVEF y el algoritmo de Gabor son 5 segundos y 0,3 segundos respectivamente. Conclusiones: El algoritmo propuesto en este estudio puede medir eficazmente el grosor muscular, de forma rápida, conveniente y precisa, y puede reflejar bien la contractilidad del músculo esquelético, lo cual es de gran valor para el reconocimiento y evaluación de la función del movimiento de grupos musculares. Nivel de evidencia II; Estudios terapéuticos- investigación de los resultados del tratamiento.

The need for adaptable global guidance in health systems strengthening for musculoskeletal health: a qualitative study of international key informants.

BACKGROUND: Musculoskeletal (MSK) conditions, MSK pain and MSK injury/trauma are the largest contributors to the global burden of disability, yet global guidance to arrest the rising disability burden is lacking. We aimed to explore contemporary context, challenges and opportunities at a global level and relevant to health systems strengthening for MSK health, as identified by international key informants (KIs) to inform a global MSK health strategic response. METHODS: An in-depth qualitative study was undertaken with international KIs, purposively sampled across high-income and low and middle-income countries (LMICs). KIs identified as representatives of peak global and international organisations (clinical/professional, advocacy, national government and the World Health Organization), thought leaders, and people with lived experience in advocacy roles. Verbatim transcripts of individual semi-structured interviews were analysed inductively using a grounded theory method. Data were organised into categories describing 1) contemporary context; 2) goals; 3) guiding principles; 4) accelerators for action; and 5) strategic priority areas (pillars), to build a data-driven logic model. Here, we report on categories 1-4 of the logic model. RESULTS: Thirty-one KIs from 20 countries (40% LMICs) affiliated with 25 organisations participated. Six themes described contemporary context (category 1): 1) MSK health is afforded relatively lower priority status compared with other health conditions and is poorly legitimised; 2) improving MSK health is more than just healthcare; 3) global guidance for country-level system strengthening is needed; 4) impact of COVID-19 on MSK health; 5) multiple inequities associated with MSK health; and 6) complexity in health service delivery for MSK health. Five guiding principles (category 3) focussed on adaptability; inclusiveness through co-design; prevention and reducing disability; a lifecourse approach; and equity and value-based care. Goals (category 2) and seven accelerators for action (category 4) were also derived. CONCLUSION: KIs strongly supported the creation of an adaptable global strategy to catalyse and steward country-level health systems strengthening responses for MSK health. The data-driven logic model provides a blueprint for global agencies and countries to initiate appropriate whole-of-health system reforms to improve population-level prevention and management of MSK health. Contextual considerations about MSK health and accelerators for action should be considered in reform activities.