Contracted Muscle Research Articles

Impact of contraction intensity and ankle joint angle on calf muscle fascicle length and pennation angle during isometric and dynamic contractions

During muscle contraction, not only are the fascicles shortening but also the pennation angle changes, which leads to a faster contraction of the muscle than of its fascicles. This phenomenon is called muscle gearing, and it has a direct influence on the force output of the muscle. There are few studies showing pennation angle changes during isometric and concentric contractions for different contraction intensities and muscle lengths. Therefore, the aim was to determine these influences over a wide range of contraction intensities and ankle joint angles for human triceps surae. Additionally, the influence of contraction intensity and ankle joint angle on muscle gearing was evaluated. Ten sport students performed concentric and isometric contractions with intensities between 0 and 90% of the maximum voluntary contraction and ankle joint angles from 50° to 120°. During these contractions, the m. gastrocnemius medialis and lateralis and the m. soleus were recorded via ultrasound imaging. A nonlinear relationship between fascicle length and pennation angle was discovered, which can be described with a quadratic fit for each of the muscles during isometric contraction. A nearly identical relationship was detected during dynamic contraction. The muscle gearing increased almost linearly with contraction intensity and ankle joint angle.

Effects of popliteal plexus block after total knee arthroplasty: a randomized clinical trial

Background and objectivesMotor-sparing peripheral nerve blocks enhance multimodal opioid-sparing strategies after total knee arthroplasty. We hypothesized that adding a popliteal plexus block to a femoral triangle block could reduce 24-hour...

PENERAPAN LATIHAN PILATES UNTUK MENGURANGI NYERI MENSTRUASI PADA REMAJA PUTRI

Dysmenorrhea is a disorder of menstrual blood flow or menstrual pain that, if not promptly addressed, can affect an individual's mental and physical functions, necessitating non-pharmacological interventions. One such non-pharmacological therapy is Pilates exercises, which relax contracted muscles and stimulate the hypothalamus to produce endorphins, a natural pain reliever that reduces pain. This community service activity aims to reduce menstrual pain in adolescent girls through Pilates exercise classes held in Dusun Luksongo, Tugurejo Village, Ngasem District, Kediri Regency. The program involves 10 adolescent girls as participants. The methods used include socialization, education, and training in Pilates techniques by a competent instructor. The training includes practical guidance on safe and effective Pilates techniques to reduce menstrual pain and enhance the well-being of the adolescent girls. The results of the service show that out of 10 adolescent girls who participated in the program, 8 girls (80%) reported a decrease in menstrual pain after attending the Pilates sessions, while 2 girls (20%) reported the pain remained the same. No participants reported an increase in pain. These results indicate that the Pilates exercise classes have a significant impact on reducing menstrual pain in adolescent girls, which is an important factor for their well-being. Therefore, the Pilates exercise class program can be considered effective in reducing menstrual pain and improving the physical and psychological health of adolescent girls, as well as strengthening their role in maintaining their own health.

Advances in non-coding RNA in tendon injuries.

Tendons serve as important weight-bearing structures that smoothly transfer forces from muscles to skeletal parts, allowing contracted muscle movements to be translated into corresponding joint movements. For body mechanics, tendon tissue plays an important role. If the tendons are damaged to varying degrees, it can lead to disability or pain in patients. That is to say, tendon injuries havea significant impact on quality of life and deserve our high attention. Compared to other musculoskeletal tissues, tendons are hypovascular and hypo-cellular, and therefore have a greater ability to heal, this will lead to a longer recovery period after injury or even disability, which will significantly affect the quality of life. There are many causes of tendon injury, including trauma, genetic factors, inflammation, aging, and long-term overuse, and the study of related mechanisms is of great significance. Currently, tendon there are different treatment modalities, like injection therapy and surgical interventions. However, they have a high failure rate due to different reasons, among which the formation of adhesions severely weakens the tissue strength, affecting the functional recovery and the patient's quality of life. A large amount of data has shown that non coding RNAs can play a huge role in this field, thus attracting widespread attention from researchers from various countries. This review summarizes the relevant research progress on non-coding RNAs in tendon injuries, providing new ideas for a deeper understanding of tendon injuries and exploring new diagnostic and therapeutic approaches.

APPLICATION OF BOTULINUM TOXIN IN CONSERVATIVE TREATMENT OF MASTICATORY MUSCLES DYSFUNCTION

The purpose of this paper is to describe the application of the botulinum toxin in diseases of the temporomandibular system of a muscular type such as masticatory hypertrophy, spasm, bruxism, and tension headaches of idiopathic etiology. The masticatory system is a complex apparatus with great adaptive capacity. Still, when that capacity is exceeded, functional disorders occur followed by a series of symptoms that depend on individual, local, and systemic etiological factors. Occlusal trauma exceeding the physiological limits of the teeth, periodontium, and TMJ leads to a series of functional disorders. Temporomandibular dysfunctions (TMD) are used to describe a large, heterogeneous group of diseases of the temporomandibular joint (TMJ) and its adjacent tissues and organs. Botulinum toxin type A, hemagglutinin complex with 500 IU (DISPORT Ipsen Biopharm, UK) was used for the therapy of muscle disorders like bruxism or night teeth clenching in female patient 26 years old. Depending on the dose that was applied to the targeted muscle, a complete or partial reduction in contraction occurs with reduced function and weakening of the muscle. Two weeks after applying the neuromodulator, the patient reported a reduction in pain and episodes of teeth grinding and clenching. Bilateral hypotrophy of left and right masseter muscles was noticeable after 2 months. We concluded that botulinum toxin could be used as an effective treatment for reducing nocturnal bruxism and myofascial pain in patients with bruxism.

Anti-Anemic and Anti-Dyspepsia Potential of Yogurt with Carao (Cassia grandis) in Rat Model

Iron deficiency anemia is a significant health problem in developing countries and this is rising, particularly in children and pregnant women. Several therapeutic properties have been attributed to Cassia grandis (carao), including the treatment against anemia, a laxative effect, and the reduction of bleeding. Yogurt is a vehicle for functional ingredients. As a result, this investigation aims to examine the application of Cassia grandis pulp as an anti-anemic and anti-dyspepsia agent in enriched yogurt. Carao pulp powder was added to milk at 0%, 0.5%, 1%, and 3% to produce yogurt. The bioavailability characteristics of iron deficiency anemia were analyzed in albino rats, which were studied for 4 weeks. Other groups of rats were used to set up the dyspepsia model by being fed a high-fat and high-calorie diet. Intestinal propulsion rate, gastric emptying rate, small intestinal contraction, motilin levels, and intestinal muscle tension were analyzed in rats with dyspepsia. Yogurt with 3% carao pulp powder restored ferritin, hemoglobin, total protein and iron at the end of the 4-week feeding period, with significant competition revealed in calcium and zinc absorbance. Furthermore, yogurt with 3% carao pulp powder improved intestinal propulsion rate, gastric emptying rate, small intestinal contraction, motilin levels, and intestinal muscle tension in dyspepsia rats. Carao can be recommended as an anti-anemia supplement in yogurt fortification.

Effects of far-infrared radiation lamp therapy on recovery from a simulated soccer-match in elite female soccer players.

We investigated the effects of far-infrared radiation (FIR) lamp therapy on changes in muscle damage and performance parameters following six sets of 15-min Loughborough intermittent shuttle test (LIST), a simulated soccer match. Twenty-four elite female soccer players (20-24 y) were assigned into FIR or sham treatment group (n = 12/group). The participants received a 60-min FIR or sham treatment (30 min per muscle) over knee extensors (KE) and flexors (KF) at 2, 25, 49, 73, and 97 h post-LIST. Maximal voluntary isometric contraction (MVC) torque and muscle soreness of the KE and KF, plasma creatine kinase (CK) activity as muscle damage markers, and several performance parameters including countermovement jump (CMJ) and Yo-Yo intermittent recovery test level 1 (YYIR1) were measured before and 1, 24, 48, 72, 96, and 120 h post-LIST. Changes in the measures were compared between groups by a mixed-design two-way ANOVA. The running distance covered during LIST and changes in the measures at 1-h post-LIST (before the treatment) were similar (p = 0.118-0.371) between groups. Changes in muscle damage markers at 24-120 h post-LIST were smaller (p < 0.05, η2 = 0.208-0.467) for the FIR (e.g., MVC-KE torque decrease at 48-h post-LIST: -1 ± 2%, peak KE soreness: 16 ± 10 mm, peak CK: 172 ± 42 IU/L) than sham group (-11 ± 9%, 33 ± 7 mm, 466 ± 220 IU/L, respectively). Performance parameters recovered faster (p < 0.05, η2 = 0.142-0.308) to baseline for the FIR (e.g., decreases at 48-h post-LIST; CMJ: 0 ± 1%, YYIR1: 0 ± 1%) than sham group (-6 ± 2%, -9 ± 6%, respectively). These results suggest that the FIR lamp therapy was effective for enhancing recovery from a soccer match.

Cervical impairments in subjects with migraine or tension type headache: an observational study.

The aim of this investigation was to compare the thickness of the deep local muscles in the neck region, as well as local and widespread sensitivity and functionality, between individuals with migraine, Tension-Type Headache (TTH), and healthy controls. To date, we know that the onset of migraine and TTH share similar pathophysiological pathways. Nevertheless, there may be some anatomical and functional differences which would explain why clinicians may obtain variable results when treating both pathological entities with similar or equal approaches. An observational study was conducted in accordance with STROBE guidelines. The flexor longus colli and multifidus, two neck-stabilizing muscles, were measured using B-mode ultrasound imaging. The upper trapezius, masseter, temporalis, tibialis anterior, and median nerve all underwent bilateral pressure-pain threshold (PPT) assessments. Ninety participants were enrolled in the study. All subjects were equally divided into TTH, migraine and control groups. The PPT values exhibited lower thresholds in patients with TTH than both migraine and healthy participants. Specifically, in the temporal muscle on both sides, patients with TTH exhibited a significantly lower threshold (p < 0.001)than both migraine and healthy participants. Patients with TTH displayed significantly lower thresholds in both upper trapezius muscles (right: p < 0.001; left: p = 0.001). Similar results were obtained for the tibialis anterior PPTs from both sides (p = 0.001 in both). However, both clinical groups exhibited lower thresholds than the healthy subjects (p < 0.001). In multifidus muscle cross-sectional area (CSA), no statistically significant differences were found between migraine patients and healthy subjects, both in relaxation and contraction (right; p > 0.05 and p > 0.05; left: p > 0.05 and p > 0.05). However, patients with TTH exhibited a smaller CSA than both migraine patients and healthy controls in multifidus relaxed and contracted state (right: p < 0.001 in both relaxed and contracted multifidus; left: p = 0.001 and p < 0.001, respectively). Similar results were obtained for the left longus colli muscle in both relaxation and contraction for patients with TTH and migraine compared with healthy subjects (p = 0.001 and p < 0.001, respectively, for muscle relaxation and p < 0.001 for muscle contraction). However, no significant differences were observed between patients with TTH and migraine (p < 0.05 in both relaxation and contraction). In the right longus colli, TTH and migraine patients had a significantly smaller CSA during contraction than healthy subjects (p < 0.001 in both comparisons). In the craniocervical flexion test, both groups of patients with TTH and migraine showed significantly lower values than healthy subjects (p < 0.001 in both comparisons). However, no significant differences were found between patients with TTH and migraineurs (p > 0.05). The findings provide a significant message for clinicians since anatomical and functional impairments were shown in patients with TTH and migraine. This study corroborates a lack of strength and smaller CSA in both clinical groups compared to controls. Therefore, strengthening programs may be addressed successfully for people with these pathological entities. To be more accurate, according to PPTs and CSA lower values in patients with TTH compared to migraine and controls, manual therapy approaches to desensitize craniocervical soft tissues and exercise therapy to increase endurance of deep cervical muscles may become meaningful especially in subjects with TTH. Nevertheless, in order to distinguish precisely between patients with TTH and migraine, different diagnostic strategies may be used in the future to describe these populations in further detail, which will assist health professionals in a more accurate treatment selection.

Evolution in the Management of Patella Fractures.

Patella fractures usually occur as a result of direct trauma to the anterior knee joint, indirect injury as a result of eccentric muscle contraction, or rapid knee flexion against a contracted quadriceps muscle. The patella functions as part of the extensor mechanism of the knee, where large forces are transmitted, and its subcutaneous nature has made treatment of patella fractures a challenge. In this review article, we evaluate how the management of these fractures has evolved over time and the advantages associated with the various treatment techniques. There are few comparative studies looking at the different treatment types for fractures of the patella, with the goal of achieving a functional extensor mechanism with low rates of post-traumatic arthritis and metal-work irritation.

Differential effects of contracting muscle mass and relative exercise intensity on arterial plasma potassium concentration during and following incremental arm and leg cycling exercise

Whilst arm cycling is commonly used during clinical testing and rehabilitation, the associated changes in arterial plasma K+ concentration ([K+]a) and thus possible risks of associated hyperkalaemia and hypokalaemia are unknown. During exercise, K+ is released from contracting skeletal muscles and simultaneously taken up by inactive muscles, with [K+]a increasing markedly during intense exercise. Hence during exercise [K+]a should be influenced by both the contracting muscle mass and the relative exercise intensity. We therefore investigated the effects of incremental one-arm (1ARM) and two-leg (2LEGS) cycling on [K+]a, and on lactate ([Lac-]), hydrogen ([H+]), adrenaline and noradrenaline. Eight healthy participants performed 1ARM, rested (3.0 ± 0.2 h, mean±SE) then performed 2LEGS, with radial arterial blood sampled at rest, during common submaximal workrates (25, 50 W), peak workrate and 1–30 min post-exercise. During exercise at 50 W, VO2, [K+]a and [Lac-]a were higher during 1ARM than 2LEGS (P < 0.05). In contrast, at peak exercise, 2LEGS (272 ± 15 W) elicited higher VO2, [K+]a, [Lac-]a, [adrenaline]a and [noradrenaline]a than 1ARM (57 ± 4 W) (P < 0.05), with [H+]a elevated only in 2LEGS (P < 0.05). A curvilinear response for [K+]a versus %VO2peak was similar between modes, until diverging close to VO2peak. The slope of the log[K+]a versus %VO2peak regression was higher in 2LEGS (P < 0.01), indicating greater [K+]a throughout exercise utilising a larger muscle mass, and similarly for [Lac-]a. In conclusion, during exercise utilising a smaller contracting muscle mass, [K+]a and [Lac-]a were greater at the same absolute submaximal work rate compared to utilising a large muscle mass. Whilst responses were similar between modes when expressed against relative exercise intensity, [K+]a and [Lac-]a were higher during exercise with a large muscle mass. Hence, for submaximal exercise, the relative intensity is more important in determining [K+]a and [Lac-]a, but the size of the contracting muscle mass still exerts a positive effect, whilst during peak exercise, the size of the active muscle mass was more important in determining [K+]a and [Lac-]a. Furthermore, arm cycling did not induce marked disturbances in [K+]a during or after exercise, suggesting minimal associated myocardial risks and thus supporting its safe use in clinical and aged populations.

Perifascial areolar tissue graft promotes angiogenesis and wound healing in an exposed ischemic component rabbit model.

Multiple studies have reported the use of perifascial areolar tissue (PAT) grafts to treat wounds involving exposed ischemic tissues, avascular structures, and defective membrane structures. Our objective was to assess the quantitative effects of PAT grafts and their suitability for wounds with ischemic tissue exposure and to qualitatively determine the factors through which PAT promotes wound healing and repair. We conducted histological, immunohistochemical, and mass spectrometric analyses of the PAT grafts. PAT grafts contain numerous CD34+ progenitor/stem cells, extracellular matrix, growth factors, and cytokines that promote wound healing and angiogenesis. Furthermore, we established a male rabbit model to compare the efficacy of PAT grafting with that of an occlusive dressing treatment (control) for wounds with cartilage exposure. PAT grafts could cover ischemic components with granulation tissue and promote angiogenesis. Macroscopic and histological observations of the PAT graft on postoperative day seven revealed capillaries bridging the ischemic tissue (vascular bridging). Additionally, the PAT graft suppressed wound contraction and alpha smooth muscle actin (αSMA) levels and promoted epithelialization. These findings suggested that PAT can serve as a platform to enhance wound healing and promote angiogenesis. This is the first study to quantify the therapeutic efficacy of PAT grafts, revealing their high value for the treatment of wounds involving exposed ischemic structures. The effectiveness of PAT grafts can be attributed to two primary factors: vascular bridging and the provision of three essential elements (progenitor/stem cells, extracellular matrix molecules, and growth factors/cytokines). Moreover, PAT grafts may be used as transplant materials to mitigate excessive wound contraction and the development of hypertrophic scarring.

Assessment of Self-report, Palpation, and Surface Electromyography Dataset During Isometric Muscle Contraction

Measuring muscle fatigue involves assessing various components within the motor system. While subjective and sensor-based measures have been proposed, a comprehensive comparison of these assessment measures is currently lacking. This study aims to bridge this gap by utilizing three commonly used measures: participant self-reported perceived muscle fatigue scores, a sports physiotherapist’s manual palpation-based muscle tightness scores, and surface electromyography sensors. Compensatory muscle fatigue occurs when one muscle group becomes fatigued, leading to the involvement and subsequent fatigue of other muscles as they compensate for the workload. The evaluation of compensatory muscle fatigue focuses on nine different upper body muscles selected by the sports physiotherapist. With a cohort of 30 male subjects, this study provides a valuable dataset for researchers and healthcare practitioners in sports science, rehabilitation, and human performance. It enables the exploration and comparison of diverse methods for evaluating different muscles in isometric contraction.

A Comprehensive Review of Muscle-Tendon Junction: Structure, Function, Injury and Repair.

The muscle-tendon junction (MTJ) is a highly specific tissue interface where the muscle's fascia intersects with the extracellular matrix of the tendon. The MTJ functions as the particular structure facilitating the transmission of force from contractive muscle fibers to the skeletal system, enabling movement. Considering that the MTJ is continuously exposed to constant mechanical forces during physical activity, it is susceptible to injuries. Ruptures at the MTJ often accompany damage to both tendon and muscle tissues. In this review, we attempt to provide a precise definition of the MTJ, describe its subtle structure in detail, and introduce therapeutic approaches related to MTJ tissue engineering. We hope that our detailed illustration of the MTJ and summary of the representative research achievements will help researchers gain a deeper understanding of the MTJ and inspire fresh insights and breakthroughs for future research.

The effects of foam rolling vs massage as recovery tools among UiTM Perlis FC footballers

A new idea of recovery has been discovered called self-myofascial release. Foam rolling is one of the self-myofascial approaches that can help to speed up the recovery process. It works by relaxing contracted muscles, improving blood and lymphatic circulation, and stimulating the stretch reflex in muscles. However, there is no previous research that studies the comparison of recovery modalities between foam rolling (FR), massage (M) and passive recovery (PAS) as tools of the recovery process on youth footballers. The aim of this study was to examine the effectiveness of FR (20 minutes of FR exercises on quadriceps, hamstrings, adductors, gluteus, and gastrocnemius), M (20 minutes of M on quadriceps, hamstrings, adductors, gluteus and gastrocnemius) and passive recovery (20 minutes sit on a bench) interventions performed immediately after a training session on Total Quality Recovery (TQR), perceived muscle soreness (VAS), jump performance, agility, sprint, and flexibility 24 hours after the training. During the two experimental sessions, 30 UiTM FC football players participated in a randomized controlled trial design. The first session was designed to collect the pretest values of each variable. After baseline measurements, the players performed a standardized football training. At the end of the training unit, all the players were randomly assigned to the FR, M and PAS recovery groups. A second experimental session was conducted to obtain the posttest values. As results, CMJ, agility (Arrowhead) and TQR showed positive effects in the FR group in comparison with the M and PAS groups at 24 hours after training. Thus, it is recommended that football coaches and physical trainers working with football players use a structured recovery session lasting approximately 20 minutes based on FR exercises that could be implemented at the end of a training session to enhance recovery between training loads.

Investigation of electromyography of the masseter and temporal muscles in children with Down syndrome aged 2 to 12 years during maximal voluntary isometric contraction and rest

Background. Muscle weakness and low muscle tone may cause chewing and swallowing disorders in people with Down syndrome. This study investigated the electromyography of the masseter and temporal muscles in children with Down syndrome, aged 2 to 12, during maximal voluntary isometric contraction and rest. Methods. The current descriptive-analytical and case-control study investigated the electromyography frequency indicators of the masseter and temporal muscles at maximum voluntary contraction and resting states in 15 children aged 2 to 12 with Down syndrome and 15 normal children of the same age. Results. The average frequency of the mean and median in the electrical signal of the masseter and temporal muscles on the left and right sides and in two different positions in children with Down syndrome is lower than in normal children. In comparing the average frequency of the mean, except for the left and right temporal muscles in the maximum voluntary isometric contraction and the left master muscle during rest, there is a significant difference in the rest. Also, in comparing the average frequency of the median, except for the left and right temporal muscles in the resting state, there are non-significant differences in the rest of the cases. Conclusion. The average frequency of the electrical signal of the masseter and temporal muscles in children with Down syndrome is lower than that of normal children. Unlike typically developing children, those with Down syndrome struggle with chewing and swallowing. Practical Implications. The data obtained from this study contributes to the enhancement of interventions and treatments for patients with Down syndrome.

Peroxisome proliferator-activated receptor γ coactivator 1α regulates downstream of tyrosine kinase-7 (Dok-7) expression important for neuromuscular junction formation

The neuromuscular junction (NMJ)—formed between a motor nerve terminal and skeletal muscle fiber—plays an important role in muscle contraction and other muscle functions. Aging and neurodegeneration worsen NMJ formation and impair muscle function. Downstream of tyrosine kinase-7 (Dok-7), expressed in skeletal muscle fibers, is essential for the formation of NMJ. Exercise increases the expression of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) in skeletal muscles and restores NMJ formation. In this study, we used skeletal muscle-specific PGC1α knockout or overexpression mice to examine the role of PGC1α in regulating Dok-7 expression and NMJ formation. Our findings revealed that Dok-7 expression is regulated by PGC1α, and luciferase activity of the Dok-7 promoter is greatly increased by coexpressing PGC1α and estrogen receptor-related receptor α. Thus, we suggest PGC1α is involved in exercise-mediated restoration of NMJ formation.

Transabdominal ultrasonography-guided biofeedback training for pelvic floor muscles integrated with stabilization exercise improved pregnancy-related pelvic girdle pain and disability: a randomized controlled trial

ObjectivesInvestigate effects of integrated training for pelvic floor muscles (PFM) with and without transabdominal ultrasonography (TAUS) imaging-guided biofeedback in postpartum women with pregnancy-related pelvic girdle pain (PPGP). DesignThree-arm, single-blinded randomized controlled trial SettingUniversity laboratory ParticipantsFifty-three postpartum women with PPGP randomized into stabilization exercise with TAUS-guided biofeedback (BIO+EXE), exercise (EXE), and control (CON) groups. InterventionsThe BIO+EXE and EXE groups underwent an 8-week exercise program, with the BIO+EXE group receiving additional TAUS-guided biofeedback for PFM training during the first 4 weeks. The CON group only received a pelvic educational session. Main outcome measuresPrimary outcomes included self-reported pain (numeric rating scale) and disability (pelvic girdle questionnaire). Secondary outcomes included functional tests (active straight leg raising [ASLR] fatigue, timed up-and-go, and 6-meter walking tests) and muscle contractibility indicated by muscle thickness changes for abdominal muscles and bladder base displacement for PFM (ultrasonographic measures). ResultsThe BIO+EXE group had lower pain [1.8 (1.5) vs. 4.4 (1.5), mean difference −2.6, 95% confidence interval (CI) −3.9 to −1.2] and disability [14% (10) vs. 28% (21), mean difference −14, 95% CI −25 to −2] and faster walking speed [3.1 seconds (1) vs. 3.3 seconds (1), mean difference −0.2, 95% CI −1.0 to −0.2] than the CON group. The EXE group only had lower pain intensity compared to the CON group [2.7 (2.0) vs. 4.4 (1.5), mean difference −1.7, 95% CI −3.1 to −0.4]. No significant differences were observed among groups in timed up-and-go, ASLR fatigue, or muscle contractibility. ConclusionsIntegrated training for PFM and stabilization with TAUS-guided biofeedback seems to be beneficial for reducing pain and disability in postpartum women with PPGP. Contribution of the paper•8-week integrated training for PFM and stabilization with TAUS imaging-guided biofeedback reduced pain and disability, although there was no change in abdominal muscle thickness and PFM function•Correct PFM contraction through visual biofeedback was effective and may be beneficial in the treatment of postpartum women with PPGP

Predicting the occurrence of in-season groin pain in male high school soccer players: a cohort study.

[Purpose] This study investigated whether pre-season HAGOS (Japanese Copenhagen Hip and Groin Outcome Scores) and eccentric muscle strength of the hip muscles predict in-season groin pain incidences in high school soccer players. [Participants and Methods] This study had a cohort design. The participants were male high school players under 18 years playing in the Japan Soccer League, which is an elite-level soccer league of that age category in Japan. The HAGOS and the strength of hip abductor and adductor muscles in eccentric contraction were measured before the season, and hip and groin pain incidences were recorded during the season. Multiple logistic regression analysis was performed to investigate the factors derived from the pre-season HAGOS and hip muscle strength tests, presumably pertaining to the development of in-season groin pain. [Results] The eccentric adductor muscle strength of the dominant leg and the HAGOS were selected as factors associated with groin pain during the season. [Conclusion] Low pre-season HAGOS and weak dominant-leg eccentric adductor muscle strength were suggested as factors to predict in-season groin pain occurrence in male high school soccer players.

The Diagnostic Value of Musculoskeletal Ultrasound in the Quantitative Evaluation of Skeletal Muscle in Chronic Thyrotoxic Myopathy: A Single-Center Study in China.

This study aimed to evaluate the quadriceps femoris in patients with chronic thyrotoxic myopathy (CTM) using musculoskeletal ultrasound and to explore its practical clinical value for the diagnosis of CTM. A total of 241 subjects recruited from the First Affiliated Hospital of Guangxi Medical University were surveyed for detailed medical history and underwent grip strength tests, fixed-distance walking, and quadriceps femoris ultrasound examinations. Differences in muscle parameters between the CTM, non-CTM, and healthy groups were analyzed. An Receiver operating characteristic (ROC) curve was established to analyze the predictive value of various ultrasound measurements for CTM, and Spearman correlation analysis and binary logistic regression were applied to explore the factors associated CTM. The quadriceps femoris contraction index, muscle thickness, muscle cross-sectional area, and pennation angle in the CTM group were significantly lower than those in the non-CTM and healthy groups (p<0.01). The ROC curve prediction showed that the pennation angle had the best sensitivity and specificity for diagnosing myogenesis, with an area under the curve of 89%. Moreover, the pennation angle of the CTM group was positively correlated with step speed (r=0.245, p=0.031) and body surface area (r=0.276, p=0.014), but negatively correlated with age (r=-0.306, p=0.007). Regression analysis showed that the quadriceps femoris contraction index, muscle thickness, pennation angle, and cross-sectional area were factors that related the CTM. After adjusting for potential confounding factors, the association between Muscle Bundle Length and CTM became significant (OR=1.99, 95% CI: 1.22, 3.35, p=0.007). Muscular echo in patients was observed to varying degrees of enhancement. Musculoskeletal ultrasonography in the quantitative analysis of muscle parameters and muscle echo of the quadriceps femoris can provide essential imaging evidence for predicting CTM.

Contractile and Tensile Measurement of Molecular Artificial Muscles for Biohybrid Robotics.

A printable artificial muscle assembled from biomolecular motors, which we have recently developed, showed great potential in overcoming the design limitations of conventional biohybrid robots as a new bio-actuator. Characterizing its contractility for extending its applicability is important. However, conventional measurement methods are composed of complex operations with poor reproducibility, flexibility, and real-time responsiveness. This study presents a new method for measuring the contractile force generated by artificial muscles. A measurement system was constructed, wherein artificial muscles were patterned by UV laser scanning in an oil-sealed microchamber, and the contractile force was measured in real time using a microforce sensor extended by a 3D-printed microcantilever. The measurement accuracy of the sensor was ensured through calibration and correction. For demonstration purposes, a series of contractile measurements were carried out using the proposed system. The relationship between contractile force and the dimensions of the activation space of the artificial muscles, as well as the tensile properties of the contracted muscle chain were evaluated. The results will help characterize the contractile properties of the artificial muscle and lay the foundations for its further application in biohybrid robotics.