Muscles

Hip joint position sense (JPS), a key component of neuromuscular function arising from muscle spindle and periarticular mechanoreceptor input, remains underexplored, with no standardized and reliable clinical protocol available to assess hip proprioception. This study evaluated the intra- and inter-rater reliability of a laser- and inclinometer-based active hip JPS protocol and established preliminary references in healthy adults. A two-phase reliability study was conducted in accordance with GRRAS and COSMIN guidelines: 17 participants for reliability analyses and 57 for preliminary references. Six movement directions were assessed (flexion, extension, abduction, adduction, medial and lateral rotations). Reliability was quantified using intraclass correlation coefficients with their 95% confidence intervals, using two-way random-effects models with absolute agreement (ICC(3,1) for intra-rater and ICC(2,1) for inter-rater analyses), interpreted as poor (<0.50), moderate (0.50–0.70), or good (≥0.70). Absolute measurement error was reported as standard error of measurement (SEM%) and 95% minimal detectable change (MDC95%), normalized to target amplitudes to allow direct cross-direction comparison. Intra-rater reliability ranged from poor to moderate, with experienced raters reaching ICC = 0.64 (95% CI [0.39; 0.80]) for medial rotation. Inter-rater reliability improved across sessions, peaking for medial rotation (ICC = 0.78; 95% CI [0.50; 0.91]). Rotational movements yielded the lowest SEM% (3–6%), indicating high measurement precision despite trial-to-trial variability (MDC% 9–31%). Normative errors were largest in flexion (21.4 cm) and smallest in rotations (≈2.2–2.3°). Despite overall low-to-moderate reliability, the protocol achieved clinically acceptable measurement precision (SEM% < 10%) for rotational tasks, whereas the laser-based sagittal and frontal-plane components remained exploratory. The protocol provides preliminary reference values for hip JPS in healthy adults and requires further validation before clinical use. Full article

Micronutrients are essential for optimal muscle metabolic function. We previously showed that heat-induced skeletal muscle injury is associated with depletion of nicotinamide adenine dinucleotide (NAD⁺) and magnesium (Mg²⁺), and boosting NAD⁺ abundance with the precursor nicotinamide riboside (NR) improves skeletal muscle integrity against heat stress in male mice. In this study, we hypothesized that NR supplementation would prevent heat-induced skeletal muscle injury in female mice. Female 6-week-old C57BL/6J mice were orally administered vehicle or NR (185 mg/kg body weight) daily for 10 days. Subsequently, they underwent a single sham or heat exposure experiment. No significant differences in muscle NAD⁺ content were observed between vehicle and NR groups or between sham and heat groups. Heat groups showed significantly lower muscle Mg²⁺ levels compared to sham groups. In vehicle groups, heat exposure caused significant inflammation, oxidative stress, mitochondrial impairment, and apoptosis in skeletal muscle compared to the sham condition. NR treatment significantly reduced these alterations. While neither heat exposure nor NR affected muscle NAD⁺ homeostasis, the protective effects of NR on skeletal muscle against heat stress were similar to those observed in male mice. Together, our results demonstrate the preventive effect of NR on muscle heat injury in female mice. This effect is associated with anti-inflammatory and antioxidative activities, mitochondrial protection, and anti-apoptosis without NAD⁺ homeostatic alterations. Full article

The DMD gene is best known for its product dystrophin, a large rod-shaped protein that plays a critical role in muscular membrane strength and integrity. Mutations affecting dystrophin lead to Duchenne muscular dystrophy, a fatal X-linked disease characterized by muscular weakness and breakdown. In addition to the full-length dystrophin product that is most often associated with disease, the DMD gene also encodes multiple shorter isoforms of dystrophin with diverse functions. One isoform in particular, Dp71, has been increasingly found to play a wide variety of roles throughout the body. In this narrative review, we consolidate the numerous studies on Dp71 to provide a comprehensive foundation for future work. We outline and summarize the current state of knowledge on the role of Dp71 in the brain, the retina, and skeletal muscles, identifying current knowns and unknowns in the field. We also explore Dp71-based therapies currently being tested in the pre-clinical landscape and identify potential limitations for clinical translation. Full article

Hemoglobin levels play an important role in oxygen delivery to skeletal muscle, and reduced levels may impair muscle function and contribute to sarcopenia, particularly in patients with cancer. The aim of the present study was to evaluate the influence of hemoglobin levels on muscle mass and function in patients with digestive tract cancer. Methods: Patients of both sexes aged up to seventy years with cancers of the digestive system undergoing surgical and clinical treatment at an oncology referral center were included. Hemoglobin levels were assessed using a blood count, and the risk of sarcopenia was estimated using the Mini Sarcopenia Risk Assessment (MSRA). A total of 82 patients were evaluated, with a mean age of 55.4 years. Colon cancer was the most prevalent (41.6%), followed by rectal (18.3%) and stomach (14.6%) cancers. The risk of sarcopenia was estimated at 85.4%, and the prevalence of low hemoglobin levels was 71.9%; 35.4% of patients presented moderate hemoglobin depletion. Hemoglobin levels showed a moderate correlation with gait speed and a slight correlation with calf circumference, handgrip strength, and MSRA score. In conclusion, the risk of sarcopenia and low hemoglobin levels are present in patients with digestive tract cancer. Additionally, hemoglobin levels positively correlate with indicators of muscle function and the risk of sarcopenia. Full article

Quadriceps muscle and tendon injuries are a significant cause of impairment of the knee extensor mechanism, ranging from minor muscle strains to complete tendon ruptures and extensive defects following oncologic resections. This narrative review provides a comprehensive analysis of contemporary concepts in anatomy, biomechanics, diagnosis, surgical management, and rehabilitation, with a particular focus on reconstructive techniques and functional outcomes. While most muscle injuries respond well to conservative management, complete quadriceps tendon ruptures typically require surgical repair to restore extensor continuity. Both transosseous suture techniques and suture anchor fixation demonstrate reliable outcomes, with no clear superiority in clinical results. Chronic ruptures present additional challenges due to tendon retraction and poor tissue quality, often necessitating advanced reconstruction methods such as V–Y tendon lengthening and augmentation with autografts, allografts, or synthetic materials. In cases of large defects, especially following soft-tissue sarcoma resection, free functional muscle transfer (FFMT) has emerged as a key reconstructive strategy. Common donor muscles include the latissimus dorsi, gracilis, rectus abdominis, and vastus lateralis, each offering specific biomechanical advantages. Functional recovery is strongly influenced by the extent of quadriceps preservation, with better outcomes observed when at least two muscle heads remain functional. Rehabilitation protocols vary depending on the surgical approach. Early controlled mobilisation is generally recommended after tendon repair, whereas FFMT requires a more cautious and prolonged rehabilitation process to allow for flap integration and reinnervation. Overall, optimal outcomes depend on a multidisciplinary approach combining appropriate surgical technique, individualized rehabilitation, and careful patient selection. Full article

Purpose: To develop a fully automated 2D nnU-Net pipeline for multi-class skeletal muscle segmentation (psoas, paraspinal, and abdominal wall) at the third lumbar (L3) vertebral level, and to quantitatively evaluate its diagnostic performance and reliability compared to manual segmentation. Materials and Methods: A 2D nnU-Net was trained on 164 axial L3 CT slices from the multi-institutional AMOS22 dataset, spanning diverse abdominal pathologies and multivendor imaging. To assess generalizability under severe anatomical distortion, independent external validation was performed in 50 consecutive patients with advanced liver disease from a single institution (January–December 2025; mean age, 63 ± 15 years; 32 women, 18 men), of whom 88% had moderate-to-severe ascites. Model stability was examined by comparing a five-fold ensemble with the best-performing single-fold model. Intra-observer reliability of the manual reference standard was evaluated in a random subset of 30 cases. Inter-observer agreement was additionally assessed using an independent second reader. Performance metrics included the Dice Similarity Coefficient (DSC), Pearson correlation coefficient (r), and Bland–Altman analysis for cross-sectional areas and mean attenuation. The inference workflow was deployed via a custom Streamlit-based graphical user interface (GUI). Results: In this anatomically complex external validation cohort, the 5-fold ensemble 2D nnU-Net achieved an overall mean DSC of 0.937 ± 0.043 (95% CI, 0.925–0.950), with 80% of cases achieving a mean DSC ≥ 0.90. While the mean DSC was statistically comparable to the best single-fold model (0.937, [95% CI, 0.921–0.952], p = 0.736), the ensemble strategy increased the minimum observed DSC (worst-case performance) from 0.720 to 0.822. Class-specific external validation performance for the 5-fold ensemble was highest for the paraspinal muscles (DSC: 0.960; 95% CI, 0.952–0.967), followed by the psoas muscles (DSC: 0.941; 95% CI, 0.927–0.956), and lowest for the anatomically complex abdominal wall muscles (DSC: 0.911; 95% CI, 0.893–0.929). Comparison between the ensemble model and manual segmentation yielded a Pearson correlation of r = 0.955 (p < 0.001) for total skeletal muscle area, with a mean bias of +7.17 cm². Intra- and inter-observer agreements for the manual reference standard demonstrated correlation coefficients of r = 0.995 and 0.090 for total areas, respectively. The automated pipeline required 3–5 s per case for inference and quantitative reporting, compared to 3–5 min for manual segmentation. Conclusions: In patients with advanced liver disease and substantial anatomical distortion from ascites, an ensemble-based 2D nnU-Net provides high quantitative agreement with manual L3 skeletal muscle segmentation, while mitigating lower-bound (worst-case) errors relative to single-fold models. Integration with a dedicated GUI enables substantial time savings and supports scalable quantitative body composition measurement. Full article

To maintain homeostatic conditions and optimal function during stressors, mitochondria initiate retrograde signaling. The mitochondrial integrated stress response (ISR) and unfolded protein response (UPR^mt) are critical quality control mechanisms activated during instances of mitochondrial perturbations. Restoration of mitochondrial homeostasis is orchestrated by three transcription factors, ATF4, CHOP, and ATF5, which upregulate protective genes to counteract stress. As the health and function of skeletal muscle are heavily dependent on a highly adaptive mitochondrial network, defining how mitochondrial health is maintained across various conditions is essential. Although several studies demonstrate the importance of these responses following instances of stress, the signaling mechanisms required to initiate such pathways remain poorly characterized in skeletal muscle. This review examines how the mitochondrial ISR/UPR^mt and related transcription factors respond to organellar stress by emphasizing the molecular events that occur during exercise, aging and muscle disuse. By consolidating the literature, this work aims to highlight the current understanding of mitochondrial stress response signaling within skeletal muscle and thus emphasize areas for future research and potential therapeutic strategies during divergent metabolic conditions. Full article

Muscle wasting contributes substantially to inflammatory bowel disease (IBD)-related disability, but its association with colitis severity across disease stages remains poorly characterized. We therefore assessed skeletal muscle mass, fiber morphology, and voluntary wheel-running performance in Winnie mice—a spontaneous Muc2 mutant model of chronic colitis—in separate female and male homozygous mutant and WT littermate cohorts. Assessments were performed at 5 weeks, before overt colitis, and at 15 weeks, in a cohort with more pronounced colitis. Outcomes included disease activity index (DAI), fecal lipocalin-2 (LCN-2), wheel-running metrics, soleus and tibialis anterior mass, and minimal Feret’s diameter distributions. At 5 weeks, Winnie mice showed no overt disease activity and no consistent structural muscle deficit. In contrast, the 15-week cohort exhibited marked colitis in both sexes, with increased DAI and LCN-2, reduced voluntary wheel-running performance, lower soleus and tibialis anterior mass, and smaller muscle fiber diameters with left-shifted size distributions. Correlation analyses identified associations between fecal LCN-2, skeletal muscle mass and size, and wheel-running distance and velocity, supporting a link between intestinal inflammation and muscle impairment in this model. These cross-sectional data are consistent with reduced voluntary activity and structural myopathy during progression of spontaneous colitis. The Winnie mouse model therefore provides a clinically relevant preclinical platform to study IBD-associated muscle wasting and its association with intestinal inflammation. Full article

Background: The Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) is used to assess upper-extremity performance in a closed kinetic chain position. The standard hand placement of 36 inches may favor individuals with larger body dimensions. Methods: Sixty-five healthy adults (44 males, 21 females; 18–33 years) performed the CKCUEST under two conditions: the standard position and a modified position with hand distance set at 50% of arm span. The mean number of touches, standard score, and power score were calculated for each condition. Reliability and the effects of sex and body composition were also examined. Results: Performance was significantly better in the modified position for mean touches (24.4 ± 4.47 vs. 23.0 ± 4.62, p = 0.001), standard score (0.4 ± 0.07 vs. 0.3 ± 0.06, p = 0.001), and power (81.1 ± 18.29 vs. 77.1 ± 22.00, p = 0.001). Both conditions showed excellent reliability (ICC = 0.944–0.946). Females performed significantly fewer touches than males in the standard position (p = 0.001), whereas this difference was not significant in the modified position. Several anthropometric and body composition variables significantly predicted performance. Conclusions: An arm-span-adjusted hand position improves CKCUEST performance and may provide a fairer assessment across individuals with different body dimensions. Full article

Background: Musculoskeletal pain remains a major cause of disability worldwide, encompassing disorders such as rheumatoid arthritis (RA), osteoarthritis (OA) and chronic back pain. Acupuncture and dry needling are increasingly used for symptom management, yet their effects on inflammatory modulation remain unclear. This systematic review and meta-analysis evaluated the influence of acupuncture on inflammatory biomarker regulation in musculoskeletal pain. Methods: Following PRISMA and Cochrane methodological guidelines, comprehensive searches were conducted across MEDLINE (via PubMed), Web of Science, Cochrane Library, Scopus, Google Scholar, and OpenEvidence from inception to August 2025. Eligible studies were randomized controlled trials (RCTs) involving acupuncture or dry needling interventions with inflammatory biomarker outcomes. Screening, data extraction, and risk of bias assessment using ROB2 were performed by two reviewers independently. The certainty of evidence was appraised using GRADE criteria. The protocol was registered on PROSPERO (CRD420251011831). Results: Nineteen RCTs and one randomized cross-over study (n = 1492) met inclusion criteria. Some studies demonstrated reductions in CRP, ESR, IL-1β, IL-6 and TNF-α following acupuncture. Random-effects meta-analysis indicated that modified acupuncture (electroacupuncture or needle-knife therapy) significantly reduced TNF-α in knee OA compared with traditional acupuncture (SMD = −1.63, 95% CI −2.47 to −0.80, p < 0.01) but not IL-1β. However, no significant effects were observed from acupuncture versus sham acupuncture for CRP or ESR in patients with arthritis. However, the findings are limited by high heterogeneity and the small number of studies included in each meta-analysis. Conclusions: A moderate level of GRADE evidence suggests that modified acupuncture may be more effective than standard acupuncture in reducing TNF-α levels in patients with OA. Further high-quality biomarker-based RCTs are warranted to confirm these findings. This study received no external funding. Full article

Centronuclear myopathy (CNM) is a genetically heterogenous congenital myopathy traditionally classified as a membrane remodeling disorder. Emerging evidence reveals that centronuclear myopathy mutations converge upon common cellular dysfunction extending beyond membrane trafficking. This review proposes a unified model positioning CNM as a disorder of impaired organelle communication and structural crosstalk. We focus on how mutations in Myotubularin1 (MTM1) and gain-of-function mutations in Dynamin 2 (DNM2) disrupt the triad architecture, leading to aberrant calcium handling, mitochondrial dysfunction, imbalanced reactive oxygen species (ROS) production, and defective autophagy. These dysfunctions are not isolated but form a pathological feedback loop that compromises muscle integrity and regeneration. By identifying shared mechanisms across CNM types, this review positions the disorder as the convergence of organelle stress and cytoskeletal network failure. This perspective reveals novel therapeutic strategies based on the principle that targeting a central pathological node may alleviate systemic dysfunction. However, given the complexity of the organelle feedback loop, a comprehensive, multi-target approach may ultimately be required to achieve full phenotypic rescue across all affected tissues. Full article

Background: Respiratory muscle strength (RMS) is a critical factor influencing athletic performance, particularly in high-intensity or prolonged activities. RMS encompasses inspiratory (IMs) and expiratory muscles (EMs), which differ in anatomical structure, fiber composition, and responsiveness to training. Methods: This pilot interventional within-subject study investigated the effects of two resistive respiratory muscle training (RMT) protocols on RMS and small airway function in eight physically active adults (two females, six males). Maximal inspiratory (MIP) and expiratory pressures (MEP), along with pulmonary function tests (PFTs), were measured using the Airofit PRO™ device and spirometry before and after two consecutive 7-day training protocols, with a 2-day break between interventions. The workload was progressively increased by lengthening the duration of forced inhalation and exhalation, while keeping the air resistance constant. Results: Results demonstrated significant improvements in MEP across both protocols and after a 10-day washout period (p < 0.001–0.03), whereas MIP showed no significant changes (p = 0.19–0.66). Moderate transient improvements were observed in small airway flow (MEF25%) following the first protocol (ES = 0.62), which regressed after the second. Conclusions: These outcomes suggest differential responsiveness of respiratory muscles to RMT; EMs, characterized by a higher proportion of fast-twitch type II fibers and a predominantly passive role in normal breathing, respond rapidly to short-duration, high-intensity forced expiration training through neuromuscular adaptations. Conversely, IMs, dominated by slow-twitch type I fibers, require longer-duration, higher-load training to elicit meaningful adaptations, explaining the limited changes in MIP. Small airway function appeared minimally trainable due to structural and physiological constraints, with short-term improvements likely reflecting effort-dependent factors rather than lasting adaptations. Finally, RMT can selectively enhance EM performance through appropriately designed short-duration, high-intensity interventions, while IMs may necessitate prolonged or higher-load stimuli. The findings highlight the importance of targeted training strategies, individualized to muscle fiber composition and functional demands, to optimize respiratory performance. Future research should investigate longer interventions, larger diverse cohorts, and precise measurement methods to further elucidate RMT’s effects on both respiratory muscles and small airway function. Full article

Background/Objectives: Sarcopenia, characterized by progressive loss of skeletal muscle mass and function, is a major public health concern among aging populations. While physical activity is recognized as protective, the comparative effectiveness of different exercise modalities remains understudied in Asian populations. This cross-sectional study investigated the association between exercise type and sarcopenia prevalence among Korean adults aged 40 years and older. Methods: This cross-sectional study analyzed data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2024. A total of 1688 adults aged ≥40 years were included. Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia (AWGS) 2019 criteria, incorporating dual-energy X-ray absorptiometry (DXA)-based appendicular skeletal muscle mass index (ASMI) and handgrip strength. Due to the absence of physical performance measures in this survey cycle, the operational definition required both low ASMI and low handgrip strength. Exercise types were categorized into four groups: no exercise, aerobic only, resistance only, and combined exercise. Multivariable logistic regression, adjusting for age, sex, socioeconomic status, lifestyle factors, nutritional intake, and comorbidities, was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: Sarcopenia prevalence was 13.2% (n = 223). In the fully adjusted model, resistance-only exercise was associated with 56% lower odds of sarcopenia (OR 0.44, 95% CI 0.23–0.82, p = 0.010), and combined exercise with 69% lower odds (OR 0.31, 95% CI 0.13–0.78, p = 0.012). Aerobic-only exercise showed no significant association (OR 0.88, 95% CI 0.54–1.42, p = 0.594). The protective association was statistically significant in the 60–69 age group (OR 0.28, 95% CI 0.11–0.74), with similar but non-significant trends in other age groups. Conclusions: Resistance exercise, either alone or combined with aerobic exercise, is associated with lower odds of sarcopenia in Korean adults aged 40 and older. These observational findings warrant further investigation through prospective and interventional studies before informing public health strategies. Interpretation should consider the limited sample size in the resistance-only subgroup (n = 18 with sarcopenia) and the cross-sectional design, which precludes causal inference. Full article

Neuromuscular electrical stimulation (NMES) is integral to studying muscle function in healthy and dystrophic mice. Certain commercial electrodes and laboratory stimulators used for NMES in mice are no longer in production. We developed and/or tested low-cost, open-source alternatives to discontinued commercial standards. We performed two studies—a comparison of electrodes and a comparison of stimulators. In the electrode study, in vivo NMES was applied to the left hindlimb ankle dorsiflexors in healthy C57BL/6J and dysferlin-null BLAJ mice using three electrode types: a previously available commercial electrode, a custom 3D-Printed electrode, and a custom Pen electrode assembled from off-the-shelf components. Twitch and tetanic torque were measured and compared using two-way repeated-measures ANOVA. Twitch torque differed by electrode type (p = 0.031), with lower values observed for the Pen electrode compared with the 3D-Printed electrode (e.g., 573 ± 72 vs. 666 ± 70 mN.mm in C57BL/6J mice), whereas tetanic torque did not differ significantly between electrode types (p = 0.060). In the stimulator study, twitch and tetanic contractions were elicited using the open-source StimJim stimulator and compared with contractions elicited by the discontinued Grass S48 stimulator. Twitch torque was lower with the StimJim (588 ± 107 mN.mm) compared with the Grass S48 (698 ± 116 mN.mm; p < 0.001), whereas tetanic torque values were not statistically different (p = 0.055). These findings indicate that open-source electrodes and stimulators can produce similar maximal tetanic torque under the tested conditions, although differences in twitch torque and stimulation parameters should be considered. These results reflect a methodological validation of accessible tools rather than a formal equivalence analysis. Full article

Stretching of the upper trapezius muscle reduces stiffness and choroidal blood flow velocity, but its effect on skin blood flow remains unclear. We evaluated the changes in upper trapezius skin circulation hemodynamics before/after self-stretching using skin laser speckle flowgraphy (LSFG). Twenty-two healthy young adults (median age [Q1–Q3]: 21.0 [20.0–21.0] years) were enrolled. Trapezius stiffness was assessed using ultrasound strain elastography, and skin and choroidal blood were measured with skin and ocular LSFG, respectively, using mean blur rate (MBR) as an index of blood flow velocity. Intraocular pressure (IOP); systolic (SBP), diastolic (DBP), and mean blood pressure (MBP); heart rate (HR); ocular perfusion pressure (OPP); salivary α-amylase (sAA) activity; and subjective eyestrain/shoulder stiffness symptoms (visual analog scale, VAS) were evaluated at baseline and after stretching. SBP, DBP, MBP, OPP, sAA activity, VAS scores for eyestrain and shoulder stiffness, trapezius stiffness, and skin and choroidal MBR decreased significantly after self-stretching, whereas IOP and HR remained unchanged. Trapezius muscle self-stretching reduces muscle stiffness and induces relaxation in healthy adults, accompanied by reduced sympathetic activity and decreased systemic, choroidal, and local skin circulation. These findings suggest that skin LSFG may serve as a useful, non-invasive tool for evaluating shoulder stiffness. Full article

Background: Tensiomyography (TMG) offers a noninvasive means of evaluating skeletal muscle contractile properties, including muscle displacement (Dm), delay time (Td), contraction time (Tc), half-relaxation time (Tr), and sustain time (Ts). When applied to lumbosacral musculature, interpretation may be influenced by changes in muscle stiffness that occur across the respiratory cycle. Understanding these fluctuations is essential for improving measurement consistency and data interpretation. Methods: Thirty healthy young adults (mean ± SD age = 21.07 ± 1.55 years) underwent TMG assessment of the erector spinae (ES) and latissimus dorsi (LD) at four distinct lung volumes: end-tidal inspiratory volume (ETIV), end-tidal expiratory volume (ETEV), total lung capacity (TLC), and residual volume (RV). Visual cues were used to guide participants’ respiratory phases. Paired-samples t-tests compared TMG parameters across respiratory conditions. Results: For the ES, significant differences were observed in Dm, Tr, and Ts between ETIV and ETEV (p ≤ 0.05), ETIV and TLC (p ≤ 0.05), and ETEV and RV (p ≤ 0.05). No statistically significant differences were identified for the LD (p ≥ 0.12). Conclusions: Some erector spinae contractile properties vary across the respiratory cycle, which may affect TMG outcomes. The findings of this research lend belief to the idea that a standardized respiratory phase during data collection may improve the reliability and comparability of TMG measurements involving trunk musculature. Future research could address the negative findings for latissimus dorsi and further determine which muscles require respiratory standardization. Full article

Although widely used, massage has not been reported to be effective in enhancing recovery from exercise-induced muscle damage in humans. Studies using massage-like interventions in animal models have, in contrast, consistently demonstrated a significant enhancement of muscle repair, reduction in muscle inflammation and enhanced return of muscle force following muscle damage. The physiology of muscle damage and repair and the putative physiological mechanisms of potential massage-induced muscle repair and post-damage recovery, including soreness sensation, edema, inflammation, protein synthesis and other related mechanisms, are reviewed in this context. Animal models have demonstrated that massage effectiveness in enhancing post-damage muscle repair is dictated by the timing, duration, force and technique of its application and may also be modified by age and sex effects. The potentially very narrow “window of effectiveness” of massage application for the enhancement of post-damage muscle repair in humans has yet to be defined. And the lack of demonstrated effectiveness for massage on post-damage muscle recovery may be due to the wide range and inconsistency of massage techniques, timing and methodologies applied in human studies. Until a specific massage application protocol is defined for massage efficacy in post-damage human muscle recovery, therapists will continue to work blind, using a variety of techniques which lack empirical validity and have an undemonstrated effectiveness for enhancing muscle repair. Full article

This study evaluated changes in upper trapezius muscle stiffness and choroidal blood flow velocity before and after ultrasonic therapy of the trapezius muscle. Participants included 27 healthy young adults in their 20 s (median age [Q1–Q3]: 21.0 [19.3–21.0]) without subjective shoulder pain. All participants received a single-session ultrasound intervention, and no control group was included. Intraocular pressure (IOP), systolic blood pressure (BP), diastolic BP, mean BP, heart rate (HR), ocular perfusion pressure (OPP), and salivary α-amylase (sAA) activity, a marker of autonomic nerve function, were assessed at baseline and after therapy. Stiffness of the upper trapezius muscle was evaluated using shear wave elastography, and choroidal hemodynamics were assessed by measuring the mean blur ratio (MBR), a relative index of macular blood flow velocity, using laser speckle flowgraphy. IOP, systolic BP, diastolic BP, mean BP, HR, OPP, sAA activity, and MBR reduced significantly after therapy. The shear elastic modulus of the trapezius muscle also decreased significantly. However, no significant correlations were observed among the parameters. Among healthy adults in their 20 s without shoulder pain, trapezius muscle ultrasound therapy may enhance parasympathetic activity, contributing to decreases in systemic and choroidal circulatory parameters. These findings indicate that ultrasound therapy for shoulder stiffness may influence local musculoskeletal characteristics, systemic and ocular circulation, and autonomic pathways. Full article

Myositis ossificans (MO) is a benign, self-limiting heterotopic ossification process that typically develops within soft tissues following trauma, although non-traumatic forms have also been described. Despite its benign nature, MO frequently represents a diagnostic challenge, particularly in its early stages when imaging findings may mimic aggressive soft-tissue tumors, leading to unnecessary biopsies or surgical interventions. This narrative review provides an updated overview of the classification, pathophysiology, and imaging features of myositis ossificans, with a specific focus on the time-dependent evolution of radiologic appearances across different imaging modalities. Radiologic findings are discussed according to disease stage, highlighting key diagnostic clues such as the zonal phenomenon and peripheral maturation pattern. In addition, the main entities included in the differential diagnosis are reviewed, with particular emphasis on imaging features that help distinguish myositis ossificans from soft-tissue sarcomas and other calcified or ossified lesions. Finally, current management strategies and the role of imaging in patient follow-up are summarized. A thorough understanding of the evolving imaging spectrum of myositis ossificans is essential for radiologists and clinicians to achieve an accurate diagnosis, guide appropriate management, and avoid overtreatment. Full article