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Background: Researchers are looking for a way to improve the myogenic differentiation of stem cells. Adipose-derived stem cells (ADSCs), known for their multipotency and regenerative capabilities, have been extensively studied for their therapeutic potential. Meanwhile, PC12 cells, derived from rat pheochromocytoma, have been found pivotal in neuroscience research, particularly as a neuronal model system. The current study investigated the effect of the PC12 adrenal pheochromocytoma cell line on the myogenic differentiation of ADSCs. Methods: This experimental study was conducted during 2019-2022 (Ahvaz, Iran). Differentiation of ADSCs was induced by using 3 μg/mL 5-azacytidine for 24 hours. Then, the culture media was changed with Dulbecco’s Modified Eagle-High Glucose (DMEM-HG) containing 5% horse serum (HS) and kept for 7 days. Different percentages of differentiated ADSCs and PC12 (100:0, 70:30, 50:50, 30:70) were cocultured for 7 days in DMEM-HG containing 5% HS. PC12 was labeled with cell tracker C7000. The real-time polymerase chain reaction and Western blotting techniques were utilized to assess gene and protein expression. All experiments were repeated three times. Data were analyzed using GraphPad Prism 8.0.2 software with a one-way analysis of variance. P

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic bone disorder characterized by episodic flare-ups in connective tissue, which are frequently followed by the formation of heterotopic ossification. The absence of available plasma-soluble biomarkers for flare-ups or heterotopic bone formation poses severe challenges to the monitoring of disease activity to measure or predict disease progression. Recently, 18-fluor-sodium fluoride positron emission tomography/computed tomography ([18F]NaF PET/CT) was introduced as a potential marker for ossifying FOP activity. This review discusses the pharmacokinetics of [18F]NaF in relation to the pathophysiology of FOP, and its use as a marker of local bone metabolism in a variety of bone-related disorders. In addition, the review specifically addresses the applicability of [18F]NaF PET/CT imaging in FOP as a monitoring modality. [ABSTRACT FROM AUTHOR]

BACKGROUND: Physical exercise participation among female students is significantly compromised throughout the academic periods of college or university due to scholastic demands and also by less parental and community encouragements. Thus, physical inactivity in female college students leads to less musculoskeletal efficiency and work performance. OBJECTIVE: Customized yogic module may be considered to enhance both aerobic and anaerobic power, pulmonary capacity and musculoskeletal efficiency for the improvement of systemic body functions among female college students. METHODS: A randomized, controlled parallel study design (n = 60; age = 20.16±2.05 years), on sedentary female college students practicing customized yogic module (n = 30) for 5 days / week for 3 months (60 min daily in the morning) to observe anthropometric, physiological, cardiopulmonary and muscular endurance indices. RESULTS: After yogic practice, a significant reduction in body fat (p < 0.05) (%), heart rate (p < 0.001), systolic blood pressure (p < 0.001), double product (p‹0.01) and rate pressure product (p < 0.05) were estimated. Significant improvement (p < 0.001) in vital capacity, forced expiratory volume in 1 sec was also observed. Evaluation of hand grip strength, maximal oxygen consumption and physical work capacity showed significant increase (p < 0.01) after yogic intervention. CONCLUSIONS: A three-month customized yogic training improved resting physiological activities, cardiopulmonary functions, musculoskeletal strength and endurance fitness due to focused breathing, mindfulness meditation and by stretching-strengthening patterns for achieving recreational physical activity among female college students. [ABSTRACT FROM AUTHOR]

Introduction. Although Chagas disease causes high levels of morbidity, the muscle function and tolerance to physical activity in Chagas disease patients are still not completely understood. Objective. To compare health-related fitness of patient groups with acute Chagas disease versus chronic Chagas disease. Materials and methods. We conducted a cross-sectional study involving 18 patients. The data were obtained from patient´s records, and functional capacity was measured with the sixminute walk test, the peripheral muscle strength with handgrip strength, and respiratory muscle strength using the maximum inspiratory pressure and the maximum expiratory pressure. Results. The 18 patients were divided in two groups: acute Chagas disease (n=9) and chronic Chagas disease (n=9). The distance walked in the six-minute walk test was lower than the predicted distance walked in both groups (p < 0.0001). The maximum expiratory pressure was lower than the predicted one (p = 0.005), and statistically significant for chronic Chagas disease patients (p = 0.02). Heart rate increased faster in the chronic Chagas disease group within the first two minutes of the six-minute walk test (p = 0.04). The sixminute walk test in the acute Chagas disease group presented a strong correlation with peripheral muscle strength (p = 0.012) and maximum inspiratory pressure (p = 0.0142), while in the chronic Chagas disease group, only peripheral muscle strength and maximum inspiratory pressure were correlated (p = 0.0259). Conclusion. The results suggest lowered functional capacity and reduced respiratory and peripheral muscle strength in patients with Chagas disease, although no differences were observed between groups. The early increase in heart rate during exercise in the chronic Chagas disease group implies a greater myocardial overload.

Fetal growth restriction (FGR) is one of the common and more complex complications of pregnancy, which refers to the inability of the fetus to reach its expected growth potential during pregnancy. The etiology of FGR is complex and varied, and may be caused by maternal, fetal or placental factors. Long-term follow-up studies of pediatric and adult patients with FGR have revealed adverse health outcomes. Fetuses with growth restriction lag significantly behind normal children in birth weight and length after delivery, and the vast majority of these children begin to experience significant growth catch-up early in life, but are at higher risk for metabolic problems. FGR is often associated with a range of long-term complications, such as neurologic deficits and abnormalities in skeletal muscle growth and metabolism, and is even associated with increased risk of metabolic syndrome and cardiovascular disease in adulthood. This has a serious impact on the physical health and quality of life of children with FGR. We summarize the pathogenic factors of FGR and its effects on the long-term health of children in order to provide theoretical support for the clinical prevention and treatment of FGR. [ABSTRACT FROM AUTHOR]

Copyright of Biomédica: Revista del Instituto Nacional de Salud is the property of Instituto Nacional de Salud of Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Naturalists leading up to the early 20th century were captivated by the diversity of limb form and function and described its development in a variety of species. The advent of discoveries in genetics followed by molecular biology led to focused efforts in few 'model' species, namely mouse and chicken, to understand conserved mechanisms of limb axis specification and development of the musculoskeletal system. 'Non-traditional' species largely fell by the wayside until their recent resurgence into the spotlight with advances in next-generation sequencing technologies (NGS). In this review, we focus on how the use of NGS has provided insights into the development, loss, and diversification of amniote limbs. Coupled with advances in chromatin interrogation techniques and functional tests in vivo, NGS is opening possibilities to understand the genetic mechanisms that govern the remarkable radiation of vertebrate limb form and function.

• Specification of ECM at the murine MTJ depended on muscle contraction. • Knockout of Tbx3 resulted in an ectopic muscle that inserted into an MTJ. • Ectopic MTJ formation was not dependent on insertion into an enthesis. • Deposition of ECM at the MTJ was also influenced by static loading. The myotendinous junction (MTJ) contributes to the generation of motion by connecting muscle to tendon. At the adult MTJ, a specialized extracellular matrix (ECM) is thought to contribute to the mechanical integrity of the muscle-tendon interface, but the factors that influence MTJ formation during mammalian development are unclear. Here, we combined 3D imaging and proteomics with murine models in which muscle contractility and patterning are disrupted to resolve morphological and compositional changes in the ECM during MTJ development. We found that MTJ-specific ECM deposition can be initiated via static loading due to growth; however, it required cyclic loading to develop a mature morphology. Furthermore, the MTJ can mature without the tendon terminating into cartilage. Based on these results, we describe a model wherein MTJ development depends on mechanical loading but not insertion into an enthesis. [ABSTRACT FROM AUTHOR]

Copyright of Revista Salud UIS is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this review was to report on the imaging modalities used to assess morphological and architectural properties of the m. triceps surae muscle in typically developing children, and the available reliability analyses. Scopus and MEDLINE (Pubmed) were searched systematically for all original articles published up to September 2020 measuring morphological and architectural properties of the m. triceps surae in typically developing children (18 years or under). Thirty eligible studies were included in this analysis, measuring fibre bundle length (FBL) (n = 11), pennation angle (PA) (n = 10), muscle volume (MV) (n = 16) and physiological cross‐sectional area (PCSA) (n = 4). Three primary imaging modalities were utilised to assess these architectural parameters in vivo: two‐dimensional ultrasound (2DUS; n = 12), three‐dimensional ultrasound (3DUS; n = 9) and magnetic resonance imaging (MRI; n = 6). The mean age of participants ranged from 1.4 years to 18 years old. There was an apparent increase in m. gastrocnemius medialis MV and pCSA with age; however, no trend was evident with FBL or PA. Analysis of correlations of muscle variables with age was limited by a lack of longitudinal data and methodological variations between studies affecting outcomes. Only five studies evaluated the reliability of the methods. Imaging methodologies such as MRI and US may provide valuable insight into the development of skeletal muscle from childhood to adulthood; however, variations in methodological approaches can significantly influence outcomes. Researchers wishing to develop a model of typical muscle development should carry out longitudinal architectural assessment of all muscles comprising the m. triceps surae utilising a consistent approach that minimises confounding errors. [ABSTRACT FROM AUTHOR]

BACKGROUND: A significant proportion of preterm infants experience developmental delay despite receiving a post discharge early interventional care. Cerebrolysin is a peptide mixture which acts similar to endogenous neurotrophic factors through promoting neurogenesis and enhancing neuronal plasticity. OBJECTIVE: To compare the effect of Cerebrolysin plus routine intervention program versus routine intervention program alone on the outcome of preterm infants at high risk for neurodevelopmental delay. METHODS: In a randomized controlled trial, high-risk preterm infants < 32 weeks' gestation who have abnormal neurological assessment at two months corrected post-natal age were randomized at 6 months corrected post natal age to receive either early intervention program or early intervention program plus Cerebrolysin injection of 0.1 mL/kg body weight every week for 3 months as an adjuvant therapy. The primary outcome was the rate of failure of the gross motor assessment at 12 months of corrected age and secondary outcomes included fine motor, language, and personal social development at 12 months corrected post-natal age as assessed by Denver Developmental Screening Test II. RESULTS: Cerebrolysin group had a significant lower number of infants diagnosed with failed gross motor development compared to infants in the routine intervention group [10 (33%) versus 21 (70%), p = 0.009]. Cerebrolysin group had a significant lower number of infants diagnosed with failed fine motor, language and personal social development compared to infants in the routine intervention group. CONCLUSION: Cerebrolysin, as an adjuvant therapy to routine early interventional care, may improve gross motor development of high-risk preterm infants at 12 months corrected post-natal age. [ABSTRACT FROM AUTHOR]

ObjectiveTo examine whether the sex-related differences in vertebral cross-sectional area (CSA) found in children and at the timing of peak bone mass-a major determinant of osteoporosis and future fracture risk-are also present at birth.Study designVertebral CSA, vertebral height, and intervertebral disc height were measured using magnetic resonance imaging in 70 healthy full-term newborns (35 males and 35 females). The length and CSA of the humerus, musculature, and adiposity were measured as well.ResultsWeight, body length, and head and waist circumferences did not differ significantly between males and females (P ≥ .06 for all). Compared with newborn boys, girls had significantly smaller mean vertebral cross-sectional dimensions (1.47 ± 0.11 vs 1.31 ± 0.12; P < .0001). Multiple linear regression analysis identified sex as a predictor of vertebral CSA independent of gestational age, birth weight, and body length. In contrast, the sexes were monomorphic with regard to vertebral height, intervertebral disc height, and spinal length (P ≥ .11 for all). There were also no sex differences in the length or cross-sectional dimensions of the humerus or in measures of musculature and adiposity (P ≥ .10 for all).ConclusionFactors related to sex influence fetal development of the axial skeleton. The smaller vertebral CSA in females is associated with greater flexibility of the spine, which could represent the human adaptation to fetal load. Unfortunately, it also imparts a mechanical disadvantage that increases stress within the vertebrae for all physical activities and increases the susceptibility to fragility fractures later in life.

The purpose of this study is to determine the normal ranges of radioulnar (i.e. medial-lateral) finger deviations during growth. We retrospectively measured radioulnar interphalangeal joint angles in 6236 properly aligned thumbs and fingers in trauma radiographs of 4720 patients aged 0 to 19 years. The mean interphalangeal joint angle of the thumb was 0.2° (standard deviation 1.5°). The average proximal interphalangeal joint angles were ulnar deviation of 2.5° (1.7°) for the index, ulnar deviation 1.7° (1.5°) for the middle, radial deviation 1.3° (1.8°) for the ring, radial deviation 2.0° (2.8°) for the little fingers. The distal interphalangeal joint angles were ulnar deviation of 2.5° (1.7°), ulnar deviation 2.1° (1.7°), radial deviation 2.1° (1.7°), radial deviation 5.1° (2.8°) from index to the little fingers. Thumbs were typically straight, whereas the index and middle fingers deviated ulnarly, and ring and little fingers radially. There were no relevant differences in sex or laterality. [ABSTRACT FROM AUTHOR]

Previous research indicates that the musculoskeletal development of pullets is improved when pullets are reared in aviaries compared to conventional rearing cages. However, there are considerable differences in rearing aviary design. To measure locomotion and musculoskeletal development of brown (n = 7) and white-feathered (n = 8) strains of pullets, 15 commercial flocks in three styles of rearing aviaries differing in structural complexity (n = 5 per style) were visited three times: 25.9 ± 6.67, 68.0 ± 4.78, and 112.1 ± 3.34 days of age. Locomotion (duration of standing, sitting, walking, running, flying, and rates jumping, flying, group running and walking) was analysed from videos recorded three times per day: at the beginning, middle, and end of the light cycle. Pullets for dissection were taken on visits 2 and 3. Pullets in the most complex system (style 3; S3) spent the most time locomoting throughout rearing (p < 0.05). Pullets in S3, particularly white-feathered strains, performed the highest rate of vertical transitions (p < 0.05). There were no differences in any of the proportional muscle weights between aviaries styles (p > 0.05) despite the differences in locomotion. White-feathered strains, however, had proportionally heavier pectoralis major (p < 0.0001), pectoralis minor (p < 0.0001), and lighter leg muscles (p < 0.0001) than brown-feathered strains. White-feathered strains and pullets in S3 also had proportionally stronger tibiae and femurs than brown-feathered strains and pullets housed in the least structurally complex system (style 1; S1) (p < 0.05). However, there were no differences found in the breaking strength of the radius and humerus between strain colours or aviary styles (p < 0.05). Therefore, strain, as well as differences in rearing aviary design, can affect the types of locomotion that growing pullets perform, which may, in turn, impact their skeletal development.

This symposium was organized to highlight new information regarding the mechanisms through which physical activity and exercise may affect the process of growth. Exercise associated anabolic effects (i.e., constructive or biosynthetic metabolic processes involved in tissue adaptation to physical activity) are varied and modulated by maturational and nutritional factors. Nonetheless, identifying common processes responsible for the many anabolic effects of physical activity may improve the ways exercise can be used in rehabilitation programs and to promote health. Thus, the overall aim of this symposium is to explore the diverse mechanisms that link physical activity with growth at both the cellular and somatic level. A conceptual model is presented that includes the interaction of central and local components of exercise modulation of growth. Central components encompass the mechanisms through which exercise of skeletal muscle groups can seemingly affect cellular growth and function throughout the body. Local components encompass those mechanisms that stimulate growth, hypertrophy, and the appearance of new mitochondria and capillaries in the muscle, bone, vascular and connective tissues involved in the specific exercise. The physiology of these putative mechanisms and their clinical applications are developed from six different perspectives.

Copyright of Manuelle Medizin is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

HOX proteins act during development to regulate musculoskeletal morphology. HOXA5 patterns skeletal structures surrounding the cervical-thoracic transition including the vertebrae, ribs, sternum and forelimb girdle. However, the tissue types in which it acts to pattern the skeleton, and the ultimate fates of embryonic cells that activate Hoxa5 expression are unknown. A detailed characterization of HOXA5 expression by immunofluorescence was combined with Cre/LoxP genetic lineage tracing to map the fate of Hoxa5 expressing cells in axial musculoskeletal tissues and in their precursors, the somites and lateral plate mesoderm. HOXA5 protein expression is dynamic and spatially restricted in derivatives of both the lateral plate mesoderm and somites, including a subset of the lateral sclerotome, suggesting a local role in regulating early skeletal patterning. HOXA5 expression persists from somite stages through late development in differentiating skeletal and connective tissues, pointing to a continuous and direct role in skeletal patterning. In contrast, HOXA5 expression is excluded from the skeletal muscle and muscle satellite cell lineages. Furthermore, the descendants of Hoxa5-expressing cells, even after HOXA5 expression has extinguished, never contribute to these lineages. Together, these findings suggest cell autonomous roles for HOXA5 in skeletal development, as well as non-cell autonomous functions in muscle through expression in surrounding connective tissues. They also support the notion that different Hox genes display diverse tissue specificities and locations to achieve their patterning activity. [ABSTRACT FROM AUTHOR]

Abstract Fetal kicking and movements generate biomechanical stimulation in the fetal skeleton, which is important for prenatal musculoskeletal development, particularly joint shape. Developmental dysplasia of the hip (DDH) is the most common joint shape abnormality at birth, with many risk factors for the condition being associated with restricted fetal movement. In this study, we investigate the biomechanics of fetal movements in such situations, namely fetal breech position, oligohydramnios and primiparity (firstborn pregnancy). We also investigate twin pregnancies, which are not at greater risk of DDH incidence, despite the more restricted intra-uterine environment. We track fetal movements for each of these situations using cine-MRI technology, quantify the kick and muscle forces, and characterise the resulting stress and strain in the hip joint, testing the hypothesis that altered biomechanical stimuli may explain the link between certain intra-uterine conditions and risk of DDH. Kick force, stress and strain were found to be significantly lower in cases of breech position and oligohydramnios. Similarly, firstborn fetuses were found to generate significantly lower kick forces than non-firstborns. Interestingly, no significant difference was observed in twins compared to singletons. This research represents the first evidence of a link between the biomechanics of fetal movements and the risk of DDH, potentially informing the development of future preventative measures and enhanced diagnosis. Our results emphasise the importance of ultrasound screening for breech position and oligohydramnios, particularly later in pregnancy, and suggest that earlier intervention to correct breech position through external cephalic version could reduce the risk of hip dysplasia. [ABSTRACT FROM AUTHOR]

During embryogenesis, the musculoskeletal system develops while containing within itself a force generator in the form of the musculature. This generator becomes functional relatively early in development, exerting an increasing mechanical load on neighboring tissues as development proceeds. A growing body of evidence indicates that such mechanical forces can be translated into signals that combine with the genetic program of organogenesis. This unique situation presents both a major challenge and an opportunity to the other tissues of the musculoskeletal system, namely bones, joints, tendons, ligaments and the tissues connecting them. Here, we summarize the involvement of muscle-induced mechanical forces in the development of various vertebrate musculoskeletal components and their integration into one functional unit. [ABSTRACT FROM AUTHOR]

Functional movement and stability of the limb depends on an organized and fully integrated musculoskeletal system composed of skeleton, muscle, and tendon. Much of our current understanding of musculoskeletal development is based on studies that focused on the development and differentiation of individual tissues. Likewise, research on patterning events have been largely limited to the primary skeletal elements and the mechanisms that regulate soft tissue patterning, the development of the connections between tissues, and their interdependent development are only beginning to be elucidated. This review will therefore highlight recent exciting discoveries in this field, with an emphasis on tendon and muscle patterning and their integrated development with the skeleton and skeletal attachments. [ABSTRACT FROM AUTHOR]

Background/Purpose: The age at menarche reflects a pubertal girl's physiologic maturity. The aims of this study were to evaluate the relationship between the age at menarche and skeletal maturation in female orthodontic patients. Methods: Hand-wrist radiographs and lateral cephalometric radiographs from 304 adolescent female subjects (age, 8–18.9 years) were selected from the files of the Department of Orthodontics, National Taiwan University Hospital (NTUH). Hand-wrist bone maturation stages were assessed using the NTUH Skeletal Maturation Index (NTUH-SMI). Cervical vertebral maturation stages (CVMS) were determined using the latest CVMS Index. Menarcheal ages were self-reported by the patients and verified by the patients' mothers. The relationships between the NTUH-SMI or CVM stages and menarcheal status were investigated. Results: More than 90% of the 148 subjects who had already attained menstruation had skeletal maturation beyond the NTUH-SMI stage four or CVMS III. However, the subjects who had never experienced menarche mostly had skeletal maturation before NTUH-SMI stage five or CVMS IV. During the period of orthodontic treatment, 19 females experienced their menarche. The mean age at menarche for the 167 female patients in total was 11.97 years. In average, menarche occurred between NTUH-SMI stages four and five or between CVM stages III and IV. The percentage of girls with menses increased from 1.2% at age 9 to 6.6% at age 10, 39.5% at age 11, 81.4% at age 12, 97% at age 13, and 100% at age 14. Compared with the results obtained 20 years previously, we found a downward shift of 0.47 years per decade for the mean age at menarche in female orthodontic patients. Conclusion: The majority of female orthodontic patients have passed the pubertal growth spurt when they experience their menarche. Menarche usually follows the pubertal growth spurt by about 1 year and occurs after NTUH-SMI stage four or CVMS III.

Musculoskeletal development and later post-natal homeostasis are highly dynamic processes, marked by rapid structural and functional changes across very short periods of time. Adult anatomy and physiology are derived from pre-existing cellular and biochemical states. Consequently, these early developmental states guide and predict the future of the system as a whole. Tools have been developed to mark, trace, and follow specific cells and their progeny either from one developmental state to the next or between circumstances of health and disease. There are now many such technologies alongside a library of molecular markers which may be utilized in conjunction to allow for precise development of unique cell 'lineages'. In this review, we first describe the development of the musculoskeletal system beginning as an embryonic germ layer and at each of the key developmental stages that follow. We then discuss these structures in the context of adult tissues during homeostasis, injury, and repair. Special focus is given in each of these sections to the key genes involved which may serve as markers of lineage or later in post-natal tissues. We then finish with a technical assessment of lineage tracing and the techniques and technologies currently used to mark cells, tissues, and structures within the musculoskeletal system., Competing Interests: Declaration of competing interest No competing interests to declare., (Copyright © 2023. Published by Elsevier Inc.)

OBJETIVOS: examinar a validade de constructo do Movement Assessment of Infants (MAI), teste composto por 65 itens, agrupados em quatro seções, que é usado para detectar paralisia cerebral. MÉTODOS: a amostra incluiu 73 bebês pré-termo brasileiros, avaliados aos quatro e aos oito meses de idade corrigida. Foram feitas análises individuais para as duas idades, com uso do modelo estatístico Rasch. RESULTADOS: o MAI é uma escala fácil para o nível de habilidade dos bebês avaliados, tanto aos quatro quanto aos oito meses de idade. Alguns itens não se enquadram nas expectativas de unidimensionalidade do modelo estatístico, o que compromete a validade de constructo do teste. CONCLUSÕES: diferenças no nível de dificuldade dos itens aos quatro e oito meses reafirmam a necessidade de perfis distintos de desempenho para cada idade. Apesar das limitações, o teste tem aspectos positivos, sendo apresentadas sugestões para revisão, visando melhorar sua validade.OBJECTIVES: to assess the validity of the Movement Assessment of Infants (MAI) test, comprised of 65 items, grouped into four sections, used to detect cerebral palsy. METHODS: the sample included 73 preterm babies, assessed between four and eight months of corrected age. Individual assessments were made for the two ages, using Rasch's statistical model. RESULTS: MAI is an easy scale for the level of ability of the babies assessed, including both age groups, four and eight months old. Some of the items do not fit the one-dimensional expectations of the statistical model, compromising test construction validity. CONCLUSIONS: differences in the difficulty level of the items at four and eight months old reaffirm the need of different performance profiles for each age. Notwithstanding the restrictions, the test has positive aspects and review suggestions are offered aiming at validity improvement.

Fetal movements in the uterus are a natural part of development and are known to play an important role in normal musculoskeletal development. However, very little is known about the biomechanical stimuli that arise during movements in utero, despite these stimuli being crucial to normal bone and joint formation. Therefore, the objective of this study was to create a series of computational steps by which the forces generated during a kick in utero could be predicted from clinically observed fetal movements using novel cine-MRI data of three fetuses, aged 20-22 weeks. A custom tracking software was designed to characterize the movements of joints in utero, and average uterus deflection of $$6.95 \pm 0.41$$ mm due to kicking was calculated. These observed displacements provided boundary conditions for a finite element model of the uterine environment, predicting an average reaction force of $$0.52 \pm 0.15$$ N generated by a kick against the uterine wall. Finally, these data were applied as inputs for a musculoskeletal model of a fetal kick, resulting in predicted maximum forces in the muscles surrounding the hip joint of approximately 8 N, while higher maximum forces of approximately 21 N were predicted for the muscles surrounding the knee joint. This study provides a novel insight into the closed mechanical environment of the uterus, with an innovative method allowing elucidation of the biomechanical interaction of the developing fetus with its surroundings. [ABSTRACT FROM AUTHOR]