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BACKGROUND: Changes in skeletal muscle mass have been indicated in studies addressing the effects of low-frequency pulsed magnetic fields on the structure and morphology of the skeletal muscle, but no relevant studies have been conducted on the morphologic changes that occur after chronic exposure to the lowfrequency pulsed magnetic field. OBJECTIVE: To observe the effects of chronic exposure to low-frequency pulsed magnetic fields on the maximal voluntary contraction and morphologic indicators of the quadriceps muscle of the leg, thereby providing a reference of muscle morphologic changes for the use of this technique as a strategy for muscle function improvement. METHODS: Seventy healthy subjects were recruited and randomly divided into a test group that received magnetic field stimulation and a control group that underwent sham treatment, with 35 subjects in each group, and the total duration of the trial was 4 weeks. The test group underwent low-frequency pulsed magnetic stimulation for 15 minutes every 48 hours, while the control group underwent sham treatment, with the same intervention interval and duration as the test group. After 4 weeks of intervention, changes in the maximum voluntary contraction value of the quadriceps muscle in different groups were observed, and B-mode ultrasonography was utilized as a means of assessment to observe changes in muscle thickness, muscle cross-sectional area, and pinnation angle indexes. RESULTS AND CONCLUSION: After 4 weeks of chronic exposure to low-frequency pulsed magnetic fields, 68 subjects completed the test. The maximum voluntary contraction value of the quadriceps muscle in the test group increased significantly (P=0.000), and the increment was significantly higher than that of the control group (P=0.008). Three indexes related to muscle morphology in the test group were significantly higher than the pre-test values (P=0.000), while in the control group, muscle thickness showed a significant reduction (P=0.020), there was no significant change in the pinnation angle, but a significant increase in the cross-sectional area (P=0.000). Intergroup comparisons revealed that the three indicators related to muscle morphology, including muscle thickness (P=0.012), pinnation angle (P=0.003), and cross-sectional area (P=0.049), were significantly higher in the test group than in the control group. The above data confirmed that the maximum voluntary contraction of the quadriceps muscle was significantly increased in healthy adults after 4 weeks of chronic exposure to the low-frequency pulsed magnetic field, and significant increases in the three muscle morphometric indices of muscle thickness, cross-sectional area, and pinnation angle were observed in the test group, providing a basis of muscle tissue morphology for the use of this technique as an exercise alternative and medical treatment strategy for muscle improvement. [ABSTRACT FROM AUTHOR]

The incubation temperature can influence chicken bone and muscle development, and breast and leg muscles may respond differently to changes therein. Ross 308 broiler eggs were incubated at 36.5°C, 37.5°C (control), 38.5°C and 39.0°C on embryonic days 4–7. M. pectoralis and M. gastrocnemius were sampled at hatching and 5 weeks post-hatching, and differences in gene expression, microstructure and energy metabolism were examined. Tibia strength was tested, and gait scoring was performed. Broiler performance was similar at slaughter age, but initial growth was slowed by the 36.5°C treatment. The 38.5°C treatment reduced the M. gastrocnemius weight and shifted the M. pectoralis/M. gastrocnemius ratio. All treatments reduced M. gastrocnemius glycogen content relative to the control. The expression of single myogenesis-related genes was altered in the M. pectoralis by 36.5°C. The results indicate that the incubation temperature influences broiler muscle energy metabolism, and that the temperature of 38.5°C hampers leg muscle development. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to provide measurements from and investigate the repeatability of diffusion kurtosis tensor parameters in the muscles of the lower legs. Methods: Test–retest acquisition of a kurtosis tensor sequence was performed in 13 healthy volunteers. Quantitative kurtosis tensor parameters were derived, and repeatability of each parameter was evaluated by muscle group and over the whole muscle through intraclass correlation coefficient (ICC) and within‐subject coefficient of variation (wsCV). Bland–Altman analysis was also conducted. Differences in parameter values by muscle group were investigated through an analysis of variance. Results: Axial kurtosis and radial kurtosis values from the test data were 0.63 ± 0.04 and 0.70 ± 0.05, respectively. Kurtosis tensor parameters from all muscle groups and over the whole muscle had wsCV below 15%. ICC for the parameters from most muscle groups was above 85%, with the lowest ICC over the whole muscle being 88.39%. The medial gastrocnemius and extensor digitorum longus showed highest repeatability. Mean, axial, and radial diffusivity had higher wsCV despite being lower‐order terms than kurtosis. Conclusion: This study sought to examine the repeatability of diffusion kurtosis tensor–derived parameters in the legs and verify that they could potentially be used as longitudinal imaging metrics. wsCV values from test–retest data indicated high repeatability throughout all examined muscle groups. There were minimal differences in kurtosis and diffusivity parameters between muscle groups in this healthy volunteer cohort. [ABSTRACT FROM AUTHOR]

Different chicken breeds exhibit distinct muscle phenotypes resulting from selective breeding, but little is known about the molecular mechanisms responsible for this phenotypic difference. Skeletal muscle is composed of a large number of heterogeneous cell populations. Differences in differentiation and interaction of cell populations play a key role in the difference of skeletal muscle phenotype. In the current study, we performed a single-cell RNA sequencing (scRNA-seq) on the leg muscle of Daheng broiler (DH, cultivated breed) and Tibetan chicken (TC, native breed) at embryonic (E) 10, E14 and E18. A comprehensive cell atlas of embryonic chicken skeletal muscle, consisting of 29,579 high-quality cells representing 6 distinct cell types was built. The differentiation trajectory of Myoblasts and fibro-adipogenic progenitors (FAPs) was constructed through pseudotemporal trajectory analysis. Our results revealed the different developmental trajectories and dynamic gene expression profiles in 3 subtypes of myoblasts and 5 FAPs subtypes of the two chicken breeds. Tibetan chicken showed earlier embryonic myogenesis and less myoblasts compared with Daheng broiler. By comparing the switch status and switch time of genes in the two breeds, SNRPG,SNRPE,EIF4EBP1 and HSP90AB1 were considered as potentially critical genes for embryonic myogenesis, and the genes MYOG,MYBPH,APOA1, and MGP played dominant roles in the embryonic adipogenesis. Intercellular interaction networks showed that strong and complex intercellular communication was contained during embryonic skeletal muscle growth and development. These findings revealed the differences of molecular mechanisms in the skeletal muscle development between TC and DH chickens. Our data provide a better understanding of skeletal muscle developmental differences between cultivated and native breeds and valuable information for genetic breeding of chicken. [ABSTRACT FROM AUTHOR]

Vision plays a fundamental role in the control of human locomotion, including walking gait. Given that side-dominance is associated with differences in motor control, the present study aimed to determine if patches obscuring half of the visual field affect left- and right-side dominant individuals' gait kinematics and accompanying leg muscle activation differently. Healthy right- (n = 15, age = 28.2 ± 5.5 years) and left-side (n = 9, age = 27.9 ± 5.8 years) dominant participants performed 10 min of walking trials on a treadmill at a self-selected speed with 5 min of rest between three randomized trials, i.e., wearing clear glasses or glasses with left-or right half-field eye patching. In addition to a set of spatiotemporal and kinematic gait parameters, the average activity during the separated gait cycle phases, and the start and end of muscle activation in % of the gait cycle were calculated from five muscles in three muscle groups. Our results indicate that gait kinematics of left- and right-side dominant participants were similar both in their dominant and non-dominant legs, regardless of half-field eye patching condition. On the other hand, inter-group differences were found in selected kinematic variables. For instance, in addition to larger but less variable step width, our results suggest larger ankle and knee ROM in right- vs. left-sided participants. Furthermore, medial gastrocnemius and biceps femoris muscle activation showed selected differences at certain phases of the gait cycle between participants' dominant and non-dominant legs. However, it was also unaffected by the half-field eye patching condition. Moreover, the endpoint of medial gastrocnemius activation was affected by side-dominance, i.e., its activation ended earlier in the non-dominant leg of right- as compared to left-side dominant participants. Our results suggest no major differences in walking gait kinematics and accompanying muscle activation between half-field eye patching conditions in healthy adults; nevertheless, side-dominance may affect biomechanical and neuromuscular control strategies during walking gait. [ABSTRACT FROM AUTHOR]

Purpose: The extensor digitorum longus (EDL) and fibularis (peroneus) tertius (FT), muscles of the anterior compartment of the leg, synergistically work to dorsiflex and evert the foot. The EDL additionally extends the lateral four toes, while the FT normally lacks this ability. Anatomical variations of the variably present FT are common, but infrequently involve the EDL. The FT has been known to give off additional accessory tendons which may alter its role in ankle and foot movement. Documentation of unique anatomical variations of the FT and EDL can assist not only anatomists, but clinicians and surgeons as well. Methods: During routine cadaveric dissection, a rare and unique bilateral presentation of the extensor digitorum longus and fibularis tertius was discovered. Results: The extensor digitorum longus was found to be missing its lateral-most tendon that would normally insert on the 5th digit. A large, overriding FT split into three tendons, with the medial-most tendon inserting to the phalanges of the 5th digit, effectively replacing the missing EDL tendon. All findings were present bilaterally. Conclusion: To our knowledge, despite previous literature of unilateral presentations like this case, a bilateral EDL and FT variation as seen here has never been reported in humans. The use of accessory fibularis muscles in tendon graft procedures, especially the FT, makes awareness of leg anatomical variations critical for surgeons operating in the area. The present case is discussed alongside other documented anatomical variations, highlighting potential clinical implications for tendon grafting and preoperative imaging. [ABSTRACT FROM AUTHOR]

Background: Fall is a major health threat to older people. The lower-limb power and rate of torque or force development (RTD or RFD) are prominently affected by aging and are crucial for maintaining postural balance. However, there have been inconsistent findings regarding the association of such aspects of lower-limb strength with falls among community-dwelling older adults. Comprehensive synthesis and appraisal are needed to examine what deficits in lower-limb rapid force generation could identify the fallers (i.e., those with a fall history or prospective falls). Methods: This systematic review searched six databases, including PubMed, Web of Science, EMBASE, Scopus, CINAHL, and Cochrane CENTRAL. Meta-analysis was conducted to aggregate standardized mean differences (SMD) or odds ratios (OR). The quality of evidence regarding each strength parameter's ability to identify fallers was assessed using the GRADE approach. Results: Twenty observational studies with 8,231 community-dwelling older adults were included (mean age: 73.5 years; male to female ratio: approximately 6:1). Moderate quality of evidence showed that the lower average leg-press power (SMD & 95% CI: -0.17 [-0.23, -0.12]; OR & 95% CI: 0.84 [0.79, 0.89]) and lower peak sit-to-stand power (Cohen's d = 0.41) could predict prospective falls in older adults, especially the injurious/recurrent falls. Low quality of evidence showed that the lower peak sit-to-stand power could also discern fall history (SMD & 95% CI: -0.58 [-0.96, -0.20]). Conversely, low to very low quality of evidence showed that the RTD of a single muscle group could not predict prospective falls and was generally unable to identify fall history in older adults. Discussions and Conclusion: The decline of entire lower-limb power appears a good indicator of prospective falls in community-dwelling older adults. Tests of entire lower-limb power required the cumulative and coordinated contractions of more leg muscles, possibly explaining why they could identify the fallers whereas the RTD or power of a single muscle group could not. Future studies are warranted to determine cut-point values of the entire lower-limb power measurements in fall-risk assessment and explore rapid force generation of a single muscle group in predicting the injurious falls among older adults. Trial registration: Registration No.: CRD42021237091. [ABSTRACT FROM AUTHOR]

1. In the following experiment meat quality traits of a Gushi-Anka F2 resource population were measured, and their heritability estimated. Intramuscular fat (IMF) had medium heritability (0.35) but leg muscle fibre density (LMD), leg muscle fibre diameter (LMF), breast muscle fibre density (BMD), fresh fat content (FFA), and absolute dry fat content (AFC) had low heritability (0–0.2). The IMF presented the most important genetic additive effect among the poultry meat quality-related traits studied. 2. The phenotypic data of meat quality traits in the Gushi-Anka F2 resource population were combined with genotyping by sequencing (GBS) data to obtain genotype data. Six meat quality traits in 734 birds were analysed by GWAS. Based on these variants, 83 significant (–log10(p) > 4.42) single nucleotide polymorphisms and four quantitative trait loci (QTL) regions corresponding to 175 genes were identified. Further linkage disequilibrium (LD) analysis was conducted on chromosome 13 (Chr13) and chromosome 27 (Chr27) QTL regions. 3. Based on the transcriptome data and GWAS results, 12 shared genes - ITGB3, DNAJC27, ETV4, C7orf50, FKBP1B, G3BP1, IGF2BP1, KCNH6, LOC416263, SCARA5, SMIM5 and TBL1XR1 were identified as candidate genes influencing muscle fibre and fat traits. [ABSTRACT FROM AUTHOR]

1. This study calculated descriptive statistics for the production traits of two broiler populations: 1) the Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF white broilers), including fat and lean lines; and 2) the Guangxi yellow broilers. Their genetic parameters were estimated, including (co)variance components, heritability (h2) and genetic correlations (rg), using the REML method. 2. Heritability estimates (h2) for NEAUHLF white broilers ranged from 0.07 to 0.61. Traits with high heritability (h2 >0.3) included body weight at 3, 5 and 7 weeks of age (BW3, BW5, BW7), carcass weight (CW), metatarsal circumference (MeC), liver weight (LW), gizzard weight (GW), spleen weight (SW) and testis weight (TeW), while in Guangxi yellow broilers, heritability estimates ranged from 0.18 to 0.76, with every trait exhibiting high heritability, except for SW (0.18). 3. Positive genetic correlations for NEAUHLF were found (rg >0.3, ranging from 0.31 to 0.84) between BW7 and metatarsal length (MeL), MeC, body oblique length (BoL), chest angle (ChA), LW, GW, heart weight (HW) and SW. Genetic correlations between abdominal fat weight (AFW) and BW1, BW3, BW5, CW, MeL, keel length (KeL), BoL and LW were positive (rg >0.3, ranging from 0.31 to 0.58). 4. Among the Guangxi population, BW (125 d of age) showed strong positive genetic correlations with all other traits (rg >0.3, ranging from 0.30 to 0.99), while AFW displayed strong positive genetic correlations with leg muscle weight (LeW), CW, BW and thigh diameter (TD) (rg >0.3, ranging from 0.44 to 0.51). 5. It was concluded that the characteristics of the two populations were different, which means there is a need to use different strategies when performing the breeding work to improve productivity and efficiency in both broiler populations. [ABSTRACT FROM AUTHOR]

Introduction: Prolonged or strenuous exercise leads to a temporary decrease in muscle function and performance, which interferes with activity of both prime movers and postural muscles. This effect of fatigue has been reported both for single segment movements and for locomotion. However, little is known regarding the effects of fatigue on anticipatory postural adjustments (APAs) during gait initiation, a task in which the control of focal movement should be strictly coupled to a feedforward control of posture. Methods: We studied APAs during gait initiation in 16 healthy well-trained adult males, searching for muscle activities that precede the backward shift of the Center of Pressure (CoP). Participants stood on a force plate for about 10 s and then started walking at their natural speed. APAs were evaluated before and after a 1 min exhausting sequence of countermovement jumps. An optoelectronic system captured the heel-off events while a force plate measured the CoP position and vertical ground reaction force. Wireless probes recorded the electromyogram of trunk and leg muscles from both sides. Results: It was observed that muscle fatigue delayed excitatory and inhibitory APAs, of about 40 and 80 ms, respectively, and a parallel delay was induced on prime movers; moreover, velocity and amplitude of backward CoP shift were reduced. Regarding APAs sign and occurrence, most of the participants showed bilateral inhibition in dorsal muscles and excitation in the ventral ones, displaying a forward "diving" strategy that was almost unaffected by fatigue. However, after fatigue, three of the "diving" participants switched to a "turning" strategy, i.e., they displayed a reciprocal activation/inhibition pattern in the dorsal muscles, compatible with a trunk rotation. Discussion: The "turning" strategy has been previously described in untrained individuals and in a toes-amputee mountain climber, who showed a "diving" approach to gait initiation when wearing his prosthetic shoes and switched to the "turning" approach when barefoot. Altogether, these results support the idea that one and the same person may develop a repertoire of postural strategies among which the central nervous system will choose, according to the personal fitness and the constraints in which the action is performed. [ABSTRACT FROM AUTHOR]

Meat quality is a key indicator of meat performance in ruminants, and its mechanism and regulation are also key to ruminant research. Studies have shown that animal meat quality is related to the gut microbiota. In this study, RT-qPCR and 16S omics were employed to assess meat quality and intestinal microbiota. The objective was to investigate the influence of seasonal variations on the meat quality of Tibetan sheep ewes by examining the rumen microflora, meat quality attributes, and associated gene expression profiles over three distinct months: May, August, and December.The results indicate that muscle tenderness was significantly greater (p < 0.001) in the grass period than in the regrowth and dry grass periods and was highest in the longest dorsal muscle. The cooking rate of the foreleg muscle was significantly greater (p < 0.05) than that during the regrowth and dry grass periods, and the pH24h significantly differed (p < 0.05) across the different seasonal periods. The crude protein content of the longest back muscle and the foreleg muscle was significantly greater (p < 0.001) than that of the wither and grass stages during the regrowth period and slightly decreased during the grass stage. The crude fat and crude ash contents of the three groups differed significantly, and the fat content during the grass stage was significantly (p < 0.05) greater than that during the regrowth stage and the wither stage. Expression analysis of genes related to meat quality revealed that the expression of the ADSL gene was significantly greater (p < 0.05) in the anterior and posterior leg muscles during the grass period than during the regrowth and wilting periods, whereas the expression of the FABP3 gene was lower than that during these two periods. Correlation analysis revealed that Rikenellaceae_RC9_gut_group was significantly positively correlated (p < 0.05) with shear forceand cooked meat percentage and significantly negatively correlated (p < 0.05). Ruminococcus and Butyrivibrio were significantly positively correlated (p < 0.05) with CAST and highly significantly positively correlated (p < 0.05). In conclusion, meat quality during different seasons is regulated by the rumen microbiota and their associated genes. [ABSTRACT FROM AUTHOR]

Resilin, an elastomeric protein with remarkable physical properties that outperforms synthetic rubbers, is a near-ubiquitous feature of the power amplification mechanisms used by jumping insects. Catapult-like mechanisms, which incorporate elastic energy stores formed from a composite of stiff cuticle and resilin, are frequently used by insects to translate slow muscle contractions into rapid-release recoil movements. The precise role of resilin in these jumping mechanisms remains unclear, however. We used RNAi to reduce resilin deposition in the principal energy-storing springs of the desert locust (Schistocerca gregaria) before measuring jumping performance. Knockdown reduced the amount of resilin-associated fluorescence in the semilunar processes (SLPs) by 44% and reduced the cross-sectional area of the tendons of the hind leg extensor-tibiae muscle by 31%. This affected jumping in three ways: First, take-off velocity was reduced by 15% in knockdown animals, which could be explained by a change in the extrinsic stiffness of the extensor-tibiae tendon caused by the decrease in its cross-sectional area. Second, knockdown resulted in permanent breakages in the hind legs of 29% of knockdown locusts as tested by electrical stimulation of the extensor muscle, but none in controls. Third, knockdown locusts exhibited a greater decline in distance jumped when made to jump in rapid succession than did controls. We conclude that stiff cuticle acts as the principal elastic energy store for insect jumping, while resilin protects these more brittle structures against breakage from repeated use. [ABSTRACT FROM AUTHOR]

Introduction: Muscle strength strongly affects soccer players' activities, but chronic ankle injuries can reduce the ability of athletes to achieve their best performance. No report exists in the literature about the role of certain muscles in affecting the vertical jump height of soccer players. Therefore, this study aimed to analyze the differences in leg muscle strength that affect the vertical jump height of soccer players after chronic ankle injury. Materials and Methods: To achieve the aim of this study, a cross-sectional design was employed by involving one team consisting of 25 Surabaya Football Association (PERSEBAYA) players. They were divided into injury and noninjury groups, according to the questionnaire. The participants were determined based on their normal body mass index (BMI), age (17-40 years), male gender, and PERSEBAYA players. The collected data included vertical jump, ankle muscle construction, and hamstring muscle data. The data were statistically analyzed using the t test and Pearson correlation (P<0.05). Results: There was no significant difference in leg muscle strength between the injured and uninjured players. Only the hamstring muscle significantly affected soccer players' vertical jump after chronic ankle injury (r=0.422, P=0.035 with moderate influence) and was not affected by the gastrocnemius, plantar, adductor, and abductor muscles. Conclusion: There was a correlation between eccentric contraction of the hamstring muscle and vertical jump height in soccer players after a chronic ankle injury. These findings benefit soccer practitioners and medical teams in designing injury management and recovery strategies for players with ankle injuries. [ABSTRACT FROM AUTHOR]

In quiet standing, the central nervous system implements a pre-programmed ankle strategy of postural control to maintain upright balance and stability. This strategy comprises a synchronized common neural drive delivered to synergistically grouped muscles. This study evaluated connectivity between EMG signals of the unilateral and bilateral homologous muscle pairs of the lower legs during various standing balance conditions using magnitude-squared coherence (MSC). The leg muscles examined included the right and left tibialis anterior (TA), medial gastrocnemius (MG), and soleus (S). MSC is a frequency domain measure that quantifies the linear phase relation between two signals and was analyzed in the alpha (8–13 Hz), beta (13–30 Hz), and gamma (30–100 Hz) neural frequency bands for feet together and feet tandem, with eyes open and eyes closed conditions. Results showed that connectivity in the beta and lower and upper gamma bands (30–100 Hz) was influenced by standing balance conditions and was indicative of a neural drive originating from the motor cortex. Instability was evaluated by comparing less stable standing conditions with a baseline—eyes open feet together stance. Changes in connectivity in the beta and gamma bands were found to be most significant in the muscle pairs of the back leg during a tandem stance regardless of dominant foot placement. MSC identified the MG:S muscle pair as significant for the right and left leg. The results of this study provided insight into the neural mechanism of postural control. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica 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.)

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica 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.)

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica 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.)

Humans have, throughout history, faced periods of starvation necessitating increased physical effort to gather food. To explore adaptations in muscle function, 13 participants (7 males and 6 females) fasted for seven days. They lost 4.6 ± 0.3 kg lean and 1.4 ± 0.1 kg fat mass. Maximal isometric and isokinetic strength remained unchanged, while peak oxygen uptake decreased by 13%. Muscle glycogen was halved, while expression of electron transport chain proteins was unchanged. Pyruvate dehydrogenase kinase 4 (PDK4) expression increased 13-fold, accompanied by inhibitory pyruvate dehydrogenase phosphorylation, reduced carbohydrate oxidation and decreased exercise endurance capacity. Fasting had no impact on 5' AMP-activated protein kinase (AMPK) activity, challenging its proposed role in muscle protein degradation. The participants maintained muscle strength and oxidative enzymes in skeletal muscle during fasting but carbohydrate oxidation and high-intensity endurance capacity were reduced. During starvation, muscle strength and endurance, are still critical for survival. Seven days of complete fasting did not reduce maximal strength in leg muscles, but maximal endurance capacity was decreased because carbohydrate oxidation was restrained. [ABSTRACT FROM AUTHOR]

BACKGROUND: Existing studies have preliminarily summarized the potential association between muscle activity of the affected lower limb and gait stability during walking in patients undergoing anterior cruciate ligament reconstruction. However, there are some issues such as incomplete observation of muscle categories, incomplete observation of walking action phases, and failure to consider synergistic effects among multiple muscle groups, which urgently require further improvement in this study. OBJECTIVE: To monitor muscle synergy information of the affected leg during walking in patients undergoing anterior cruciate ligament reconstruction and to analyze the association between muscle synergy information and gait stability. METHODS: Twenty-four male patients aged (21.66±4.09) years undergoing anterior cruciate ligament reconstruction, were recruited. Electromyographic and center of pressure data were collected from the affected lower limb during walking. A non-negative matrix decomposition algorithm was used to extract the number of muscle synergic elements from the affected leg, the time spent in peak activation of each muscle synergic element, and the muscle relative weight indexes. Correlation analysis was then performed with the center of pressure indexes. RESULTS AND CONCLUSION: Six types of muscle synergies were identified in the affected leg. The number of muscle synergic elements showed no significant correlation with the distance and speed of lateral displacement of the center of pressure. Regarding the peak activation time of muscle synergic elements, synergic element 3 in the dominant gait loading response period showed a significant negative correlation with the lateral displacement distance of the center of pressure (r=-0.413, P=0.045) and a significant negative correlation with the lateral displacement velocity of the center of pressure (r=-0.470, P=0.020). The activation time of the remaining types of muscle synergic elements was not significantly related with patient’s gait stability indices. In terms of muscle relative weights, the rectus femoris muscle of synergistic element 1 in the dominant gait loading response period showed a significant negative correlation with the lateral displacement distance of the center of pressure (r=-0.592, P=0.005) and a significant negative correlation with the lateral displacement speed of the center of pressure (r=-0.529, P=0.014). Additionally, the relative weight of the biceps femoris muscle of synergistic element 3 in the dominant gait loading response period showed a significant negative correlation with the lateral displacement distance of the center of pressure (r=-0.428, P=0.037). To conclude, the central system in patients undergoing anterior cruciate ligament reconstruction regulates the synergistic muscle activity of the affected leg during walking to enhance gait stability in two primary ways: by prolonging the activation time of the muscle synergists during the dominant loading response period and enhancing the activation of the quadriceps muscle, in order to enhance the control of eccentric contractions of the knee joint during the landing of the affected leg and improve the stability of the knee joint; and by increasing the activation of the biceps femoris muscle during the loading response period, which increases the degree of knee flexion and enhances the lower limb's cushioning function during the landing of the affected leg. [ABSTRACT FROM AUTHOR]

This study aimed to validate the ultrasound speckle tracking (UST) algorithm, determine the optimal probe location by comparing normalized cross-correlation (NCC) values of muscle displacement at two locations (proximal vs. middle) of the biceps femoris long head (BFlh) using the UST, and investigate the effects of Nordic hamstring curl exercise (NHE) training on BFlh displacement. UST efficacy was verified with ex vivo uniaxial testing of porcine leg muscles. Ten participants (mean age 23.4 y) were recruited for comparison of NCC values between the proximal and middle BFlh during maximal knee flexor eccentric contraction using an ultrasound device and isokinetic dynamometer. Using the above devices, electromyography and shear wave elastography, the effects of an 8-wk NHE program on the morphomechanical profiles, displacement and activation of the middle BFlh and eccentric torque of the knee flexor were investigated in 20 males (mean age 23.5 y). The validity of UST was confirmed by comparing UST and ex vivo test results (r = 0.99). The NCC values of the middle BFlh were greater than those of the proximal BFlh. The caudal-direction displacements of the BFlh in the dominant leg were reduced after the NHE training (from 3.98 ± 3.84 to 1.50 ± 4.17 mm, p < 0.05). The magnitude of reduction was associated with improved eccentric strength of the knee flexor muscle in the dominant leg (r = 0.63). UST is a validated tool for measuring muscle displacement. NHE training decreased caudal-direction muscle displacement in the BFlh and increased eccentric strength. [ABSTRACT FROM AUTHOR]

Fatigue can significantly alter an athlete’s biomechanics and performance, which can increase their risk of injury. Important basketball moves like jump shots (JS) and countermovement jumps (CMJ) primarily use the muscles in the lower back and lower limbs. Basketball players’ jumping mechanics, performance, and risk of injury during CMJ, JS, and ankle sprains were all examined. A total of 415 male collegiate basketball players participated in the league, this season representing varying levels of jumping mechanics. Surface electromyography, a force plate, and a 3D motion analysis system were used to gather data. Field-goal percentage, the center of mass’s (CM) lowest point, joint angles during takeoff and landing, and Electromyography data from the lower leg muscles, erector spinae limbal, and rectus femoris were among the parameters that were recorded. Lower back muscle tiredness was created, and performance was evaluated after the fatigue. Data was analyzed using SPSS, with paired-sample t-tests, logistic, and Multiple Regression tests employed to examine the impact of fatigue on performance and injury risk. These tests assessed how fatigue affects shooting accuracy and joint angles, and increases the chance of injuries in basketball players. Following a period of tiredness, athletes’ field-goal percentages significantly decreased, whereas their CM lowest point increased on jump shots. In both CMJ and JS, fatigue leads to reduced knee flexion angles and increased ankle plantar flexion during landing, changing the contribution ratio of both legs. Due to impaired mechanics, these biomechanical changes suggest an increased probability of ankle sprains and an elevated risk of damage, especially during landing. The risk of lower back, knee, and ankle injuries increased due to major athletic impairments and altered landing mechanics caused by lower back muscular fatigue. To reduce basketball players’ risk of injury, these data highlight how crucial it is to address fatigue in training and recovery plans. [ABSTRACT FROM AUTHOR]

AbstractPurposeMaterial/MethodsResultsConclusion\nIMPLICATIONS FOR REHABILITATIONTo investigate the relationship between the distribution and severity of hypertonicity and spasticity on walking speed in people with neurological injuries.This cross-sectional observation cohort study used the Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS) to assess hypertonicity and spasticity of the gastrocnemius, soleus, hamstrings and quadriceps. Participants were classified as having a distal (gastrocnemius and/or soleus), proximal (hamstrings and/or quadriceps) or mixed distribution of hypertonicity or spasticity. The 10-m walk test was used to quantify walking speed.Seventy-five individuals with an adult-onset neurological condition participated. Those with a mixed distribution of hypertonicity or spasticity walked more slowly than those with a distal distribution. This finding was statistically significant when examining spasticity (0.54 vs 1.05 m/sec, p = 0.005), not hypertonicity (0.73 vs 1.05 m/sec, p = 0.162). The higher the severity score of hypertonicity or spasticity, the lower the walking speed. This finding was statistically significant when examining hypertonicity (r = −0.502, p < 0.001), but not spasticity (r = −0.171, p = 0.143).The severity of hypertonicity demonstrated a relationship with walking speed, whereas the severity of spasticity did not. Results for the MAS and MTS are not interchangeable.Although utilising similar scoring mechanisms, the results for the Modified Ashworth Scale and Modified Tardieu Scale are not interchangeable.People with higher Modified Ashworth Scale scores may be expected to walk more slowlyPeople with hypertonicity or spasticity affecting proximal leg muscles may be expected to walk more slowlyAlthough utilising similar scoring mechanisms, the results for the Modified Ashworth Scale and Modified Tardieu Scale are not interchangeable.People with higher Modified Ashworth Scale scores may be expected to walk more slowlyPeople with hypertonicity or spasticity affecting proximal leg muscles may be expected to walk more slowly [ABSTRACT FROM AUTHOR]

This study compared the effects of 90° versus 40° hip flexion in the leg extension exercise on quadriceps femoris muscle hypertrophy. Twenty-two untrained men completed a ten-week intervention comprising two resistance training sessions per week. A within-participant design was used, with the lower limb side randomly allocated to the 40 or 90° condition. Muscle thickness of distal and proximal rectus femoris and vastus lateralis was quantified via ultrasound. Data were analysed within a Bayesian framework including univariate and multivariate mixed effect models with random effects to account for the within participant design. Differences between conditions were estimated as average treatment effects (ATE) and inferences were made based on posterior distributions and Bayes Factors (BF). Results indicated a greater hypertrophic response in the rectus femoris for the 40° condition, with “extreme” evidence supporting a hypertrophic response favouring the 40° hip angle for the rectus femoris (BF > 100; p(Distal/ATE & Proximal/ATE >0) > 0.999), and “strong” evidence supporting no difference in hypertrophic response for the vastus lateralis (BF = 0.07). Therefore, both conditions could be viable options for increasing quadriceps femoris hypertrophy. However, when training for maximizing rectus femoris hypertrophy among untrained men, we suggest training with a reduced hip flexion in the leg extension exercise. [ABSTRACT FROM AUTHOR]

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Background: Deformities of the foot represent a significant clinical problem. Toe separators constitute an available tool used in various forms of conservative treatment, primarily used for the correction of hallux valgus, but also for improvement in the condition of neurological patients, e.g., after a stroke, or to treat dermatological problems. The goal of this systematic review is to critically assess the current scientific literature on the application of toe separators as a therapeutic intervention in physiotherapy. Methods: A systematic search was conducted across several electronic databases, such as PubMed, Science Direct, and Web of Science. The review included randomized controlled trials, quasi-experimental studies, and observational studies that explored the use of toe separators in physiotherapeutic interventions. Two independent reviewers evaluated all search results to determine eligible studies and assess their methodological quality. Results: A total of 1020 studies were found through the database search. Out of these, 10 studies met the inclusion criteria and were incorporated into the review. The sample sizes of the selected studies varied from 9 to 90 participants. In the majority of the studies, the methodological quality was not mentioned, and a frequent lack of information was noted. Based on a literature analysis, separators were primarily used as a tool for the correction of hallux valgus, but there are also promising results for use in neurology and dermatology as well as affecting the lower leg muscles during gait. Conclusions: The use of toe separators can be a valuable tool for the conservative treatment of hallux valgus and the associated deformities. The research so far varies in describing the type, material, and method of the application of the separators. Studies showed a variety of applications as well as variation in the use of materials. Further research is needed to establish the effectiveness of toe separators in foot disorders more precisely. [ABSTRACT FROM AUTHOR]

ABSTRACT We present a family with two male siblings diagnosed with a newly described digenic myopathy, involving likely pathogenic loss‐of‐function variants in the SRPK3 and TTN genes: hemizygous p.(Pro68ArgfsTer55) and heterozygous p.(Trp14174Ter), respectively. Both siblings experienced prenatal disease onset, characterized by weak fetal movements, but showed significant clinical improvement over two last years of our follow‐up. Key features included early onset, delayed motor development, and prominent axial and proximal weakness, while adult variants' carriers remained asymptomatic, without any myopathic or cardiac manifestations. Lower limb MRI revealed distinctive abnormalities, with different patterns between the siblings: the older brother showed more pronounced involvement of the thigh muscles, while the younger brother exhibited greater changes in the lower leg muscles. Given the early stage of the disease in our patients and the initial changes observed on MRI, we suggest that the semitendinosus and vastus lateralis muscles are primarily involved at the thigh level in SRPK3/TTN‐myopathy. This case highlights the importance of considering digenic inheritance in neuromuscular disorders and underscores the necessity of comprehensive genetic analysis in similar cases. [ABSTRACT FROM AUTHOR]

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Background: The clinical evaluation for disuse muscle atrophy usually depends on qualitative rating indicators with subjective judgments of doctors and some invasive measurement methods such as needle electromyography. Surface electromyography, as a non-invasive method, has been widely used in the detection of muscular and neurological diseases in recent years. In this paper, we explore how to evaluate disuse muscle atrophy based on surface electromyography; Methods: Firstly, we conducted rat experiments using hind-limb suspension to create a model of disuse muscle atrophy. Five groups of rats were suspended for 0, 3, 7, 14, and 21 days, respectively. We induced leg electromyography of rats through electrical stimulation and used fluorescence staining to obtain the fiber-type composition of rats' leg muscles. We obtained the best-fitting frequency bands of power spectrum density of surface electromyography for type I and type II fibers in rats' leg muscles by changing the frequency band boundaries. Secondly, we conducted tests on the human body and collected the electromyography of the atrophied muscles of the subjects over a period of 21 days. The changes in muscle fiber composition were evaluated using the frequency bands of power spectrum density obtained from rat experiments. The method was to evaluate the changes in type I fibers by the changes in the area of the best-fitting frequency band of type I fibers and to evaluate the changes in type II fibers by the changes in the area of the best-fitting frequency band of type II fibers. Results: The results of rat experiments showed that type I fibers best fit the frequency band of 20–330 Hz and type II fibers best fit the frequency band of 176–500 Hz. The results of human testing showed that the atrophy of the two types of fibers was consistent with the changes in the areas of the corresponding best-fitting frequency bands. Conclusions: The test results demonstrate the feasibility of using surface electromyography to evaluate muscle fiber-type composition and subsequently assess muscle atrophy. Further research may contribute to the diagnosis and treatment of disuse muscle atrophy. [ABSTRACT FROM AUTHOR]

Background: Bird is important in maintaining biodiversity and its lifestyles and behaviors will pose an important impact on the ecological environment. Birds are also inseparable for ecological stability. Birds' movement and living habits are a widely studied topic. Methods: Two economic valuable birds, Lonchura striata and Copsychus saularis, were selected in this study. It aims at investigating the characteristics of muscle fiber tissues and comparing the differences between male and female species. Histological techniques were used to determine the characteristics of the muscle fiber (diameter, area and density) in leg and pectoral muscles. Result: There were differences in the muscle fiber characteristics of the Lonchura striata and the Copsychus saularis. The characteristics of muscle fibers between males and females of the same species were significantly different and there were also significant differences in the same parts of different species. The diameter and area of muscle fibers are correlated to the density of muscle fibers. This study suggested that the characteristics of muscle fibers are related to their living habits and population characteristics. [ABSTRACT FROM AUTHOR]

The neuromuscular circuit mechanisms of freezing of gait in Parkinson's disease have received little study. Technological progress enables researchers chronically to sense local field potential activity of the basal ganglia in patients while walking. To study subthalamic activity and the circuit processes of supraspinal contributions to spinal motor integration, we recorded local field potentials, surface EMG of antagonistic leg muscles and gait kinematics in patients while walking and freezing. To evaluate the specificity of our findings, we controlled our findings to internally generated volitional stops. We found specific activation–deactivation abnormalities of oscillatory activity of the subthalamic nucleus both before and during a freeze. Furthermore, we were able to show with synchronization analyses that subthalamo-spinal circuits entrain the spinal motor neurons to a defective timing and activation pattern. The main neuromuscular correlates when turning into freezing were as follows: (i) disturbed reciprocity between antagonistic muscles; (ii) increased co-contraction of the antagonists; (iii) defective activation and time pattern of the gastrocnemius muscle; and (iv) increased subthalamo-muscular coherence with the gastrocnemius muscles before the freeze. Beyond the pathophysiological insights into the supraspinal mechanisms contributing to freezing of gait, our findings have potential to inform the conceptualization of future neurorestorative therapies. [ABSTRACT FROM AUTHOR]

Objectives: Some young individuals participating in sports activities may encounter lower leg muscle pain and tightness, potentially indicating chronic exertional compartment syndrome (CECS). While muscle pressure measurement is typically recommended for diagnosis, it is invasive and associated with low sensitivity and specificity. Thus, there is a need for novel diagnostic approaches. Methods: This feasibility study aims to assess whether an ultrasound-guided technique can effectively measure the compressibility of the anterior tibial muscle compartment, focusing on optimal leg positioning and identifying reliable external and internal anatomical landmarks. The compressibility of the anterior tibial muscle compartment was evaluated using ultrasound images obtained at 10 mmHg and 80 mmHg external pressure, with the drop in compartment thickness used to calculate the compressibility ratio. Measurements were conducted in various leg positions and utilizing different external and internal landmarks. Results: Studies in healthy volunteers showed that knee and heel support positioning, measuring at the leg's widest circumference, and using the interosseous membrane as an internal landmark yielded the lowest measurement variability with an intra class correlation of.977 (.764–1.000; 95%-confidence interval). Conclusion: These findings suggest that ultrasound-guided techniques can feasibly determine the compressibility ratio of the anterior tibial muscle compartment, providing valuable insights for standardized protocols in future studies on suspected cases of chronic exertional compartment syndrome. [ABSTRACT FROM AUTHOR]

Background/Objectives: The active straight leg raise requires intricate coordination between the hip, knee, pelvis, and spine. Despite its complexity, limited research has explored the relationship between lower limb raising velocity and trunk muscle motor control during an active straight leg raise in healthy individuals. This study aimed to explore the potential effects of increased lower limb raising velocity on core muscle contractions during active straight leg raises. Methods: Six healthy adult men (mean age: 24.5 ± 2.5 years) participated in this study. Electromyography signals were recorded using surface electrodes placed on the rectus abdominis, external oblique, and internal oblique/transverse abdominis muscles. The participants performed active straight leg raises at three different velocities: 3 s, 2 s, and as fast as possible (max). The electromyography data were analyzed from 250 ms before to 1000 ms after movement initiation, with muscle activity expressed as a percentage of the maximal voluntary isometric contraction. Statistical analyses were conducted using non-parametric tests, including the Friedman test for overall differences, followed by pairwise Wilcoxon signed-rank tests with Bonferroni correction for multiple comparisons (p < 0.05). Results: During the 250 ms before movement initiation, the internal oblique/transverse abdominis, external oblique, and rectus abdominis muscles showed greater activity in the max condition compared to the 3 s and 2 s conditions (Friedman test, p < 0.05), but no significant differences were found in pairwise comparisons (Wilcoxon test, p > 0.05). Similarly, during the 500 ms after movement initiation, internal oblique/transverse abdominis activity was higher in the max condition, with no significant pairwise differences observed. Conclusions: Faster lower limb raising velocities during active straight leg raise may enhance core stability by activating anticipatory and sustained internal oblique/transverse abdominis, external oblique, and rectus abdominis activity on the raised limb side. Training to promote this activation could improve dynamic stability in rapid or asymmetric movements. [ABSTRACT FROM AUTHOR]

Background/Objectives: Previous studies have shown that neuromuscular electrical stimulation (NMES), while expensive, can provide some of the health benefits of exercise to people who cannot exercise their legs normally. The aim of this study was to quantify the increases in muscle metabolism in four muscles of the legs of able-bodied individuals with NMES. Methods: Healthy college-aged students were tested. NMES of four muscle groups was performed with inexpensive stimulators and reusable tin foil electrodes. The biceps femoris, vastus lateralis, medial gastrocnemius, and tibialis anterior muscles on one leg were stimulated for ten minutes with twitch stimulations at the highest comfortable stimulation current. Muscle metabolism was measured using the slope of oxygen consumption measured with near-infrared spectroscopy (NIRS) during 5 s of cuff ischemia. Results: Initial studies found fold increases in muscle metabolism above rest of 8.9 ± 8.6 for the vastus lateralis, 7.9 ± 11.9 for the biceps femoris, 6.6 ± 7.8 for the medial gastrocnemius, and 4.9 ± 3.9 for the tibialis anterior. Some participants were able to obtain large increases in muscle metabolism, while other participants had lower increases. Conclusions: The ability to produce large increases in metabolism has the potential to allow NMES to replace or augment exercise to improve health in people who cannot otherwise exercise. The devices used were inexpensive and could be adapted for easy use by a wide range of individuals. [ABSTRACT FROM AUTHOR]

Magnetization transfer (MT) magnetic resonance imaging (MRI) can be used to estimate the fraction of water and macromolecular proton pools in tissues. MT modeling paired with ultrashort echo time acquisition (UTE‐MT modeling) has been proposed to improve the evaluation of the myotendinous junction and fibrosis in muscle tissues, which the latter increases with aging. This study aimed to determine if the UTE‐MT modeling technique is sensitive to age‐related changes in the skeletal muscles of the lower leg. Institutional review board approval was obtained, and all recruited subjects provided written informed consent. The legs of 31 healthy younger (28.1 ± 6.1 years old, BMI = 22.3 ± 3.5) and 20 older (74.7 ± 5.5 years old, BMI = 26.7 ± 5.9) female subjects were imaged using UTE sequences on a 3 T MRI scanner. MT ratio (MTR), macromolecular fraction (MMF), macromolecular T2 (T2‐MM), and water T2 (T2‐W) were calculated using UTE‐MT modeling for the anterior tibialis (ATM), posterior tibialis (PTM), soleus (SM), and combined lateral muscles. Results were compared between groups using the Wilcoxon rank sum test. Three independent observers selected regions of interest (ROIs) and processed UTE‐MRI images separately, and the intraclass correlation coefficient (ICC) was calculated for a reproducibility study. Significantly lower mean MTR and MMF values were present in the older compared with the younger group in all studied lower leg muscles. T2‐MM showed significantly lower values in the older group only for PTM and SM muscles. In contrast, T2‐W showed significantly higher values in the older group. The age‐related differences were more pronounced for MMF (−17 to −19%) and T2‐W (+20 to 47%) measurements in all muscle groups compared with other investigated MR measures. ICCs were higher than 0.93, indicating excellent consistency between the ROI selection and MRI measurements of independent readers. As demonstrated by significant differences between younger and older groups, this research emphasizes the potential of UTE‐MT MRI techniques in evaluating age‐related skeletal muscle changes. [ABSTRACT FROM AUTHOR]

The article in the Journal of Magnetic Resonance Imaging discusses the reliability and agreement of manual region of interest (ROI) segmentation methods in tissue sodium magnetic resonance imaging (23Na MRI). The study found good to excellent inter-rater and intrarater reliability for skin, leg muscle, tibial bone, and whole leg tissue segmentation. However, there was a clinically unacceptable bias in mean sodium concentration when comparing different skin segmentation methods. The research highlights the importance of establishing standards in ROI segmentation methods for wider clinical use of 23Na MRI technology. [Extracted from the article]

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This study proposes a new method called "thermopixelgraphy" for analyzing thermal images (TI) through quantifying pixels classified as cold, neutral and hot. For this, we analyzed 30 professional male football players (27.2 ± 4.4 yrs., 69.8 ± 6.6 kg; of 9.8 ± 3.0% of body fat). Thermographic images were obtained in 13 games played in the Brazilian league. Images of the lower limbs (anterior and posterior) were obtained at three moments: M1 (24 h before); M2 (24 h after); M3 (48 h after the match). The total number of pixels in each image were quantified and classified as: (a) cold 28.0–31.0 °C; (b) neutral 31.1–33.0 °C and; (c) Hot 33.1–36.0 °C. The main results showed a higher frequency of pixels in the cold (mainly between 30 and 31 °C; n = 1551.9) and neutral zones (mainly between 32 and 33 °C; n = 2253.9) for the anterior view of the right lower limb at moment M1 and a higher frequency of pixels in the neutral (mainly between 32 and 33 °C; n = 2622.8) and hot zones (mainly between 33 and 34 °C; n = 2579.5) at moment M2 for the posterior view (M1: cold zone 30–31 °C; n = 1319.1; neutral zone 31–32 °C; n = 2835.8; M2: neutral zone 32–33 °C; n = 2939.5; and hot 33–34 °C; n = 3066.5). Similar results were observed for the left leg. In conclusion, "thermopixelgraphy" quantifies the number of pixels from TI and the image analysis process is faster, more accurate, encompasses all areas of the thigh and leg muscles, and does not require extensive prior experience from the evaluator. [ABSTRACT FROM AUTHOR]

While exoskeleton technology is becoming more and more common for gait rehabilitation in children with neurological disorders, evaluation of gait performance still faces challenges and concerns. The reasoning behind evaluating the spinal locomotor output is that, while exoskeleton's guidance forces create the desired walking kinematics, they also affect sensorimotor interactions, which may lead to an abnormal spatiotemporal integration of activity in particular spinal segments and the risk of abnormalities in gait recovery. Therefore, traditional indicators based on kinematic or kinetic characteristics for optimizing exoskeleton controllers for gait rehabilitation may be supplemented by performance measures associated with the neural control mechanisms. The purpose of this study on a sample of children was to determine the basic features of lower limb muscle activity and to implement a method for assessing the neuromechanics of spinal locomotor output during exoskeleton-assisted gait. To this end, we assessed the effects of a robotic exoskeleton (ExoAtlet Bambini) on gait performance, by recording electromyographic activity of leg muscles and analyzing the corresponding spinal motor pool output. A slower walking setting (about 0.2 m/s) was chosen on the exoskeleton. The results showed that, even with slower walking, the level of muscle activation was roughly comparable during exoskeleton-assisted gait and normal walking. This suggests that, despite full assistance for leg movements, the child's locomotor controllers can interpret step-related afferent information promoting essential activity in leg muscles. This is most likely explained by the active nature of stepping in the exoskeleton (the child was not fully relaxed, experienced full foot loading and needed to maintain the upper trunk posture). In terms of the general muscle activity patterns, we identified notable variations for the proximal leg muscles, coactivation of the lumbar and sacral motor pools, and weak propulsion from the distal extensors at push-off. These changes led to the lack of characteristic lumbosacral oscillations of the center of motoneuron activity, normally associated with the pendulum mechanism of bipedal walking. This work shows promise as a useful technique for analyzing exoskeleton performance to help children develop their natural gait pattern and to guide system optimization in the future for inclusion into clinical care. [ABSTRACT FROM AUTHOR]

Context. The genotype of laying hens is one of the most important factors influencing their carcass composition and anatomical features. Aims. The aim of the present study was to compare two genotypes of laying hens, Lohmann Brown and Lohmann White, after the laying period. Methods. The experimental material consisted of 26 carcasses obtained after slaughtering spent laying hens at the age of 83 weeks. Key results. The genotype of the birds had a significant (P < 0.05) effect on carcass weight, and the proportion (%) of the breast muscle, leg muscle and gizzard weight. Significant correlations were also found between bodyweight and the weight of the stomach, proventriculus, liver and spleen. The origin of the laying hens also had a significant impact on the length of the sections on intestinal segments, namely, jejunum, ileum and colon. Significant differences in the correlations between bodyweight and length of duodenum, jejunum and rectum were also found. The compared hybrids of laying hens differed significantly in the dimensions of the femur and tibia. Lohmann Brown (LB) hens were characterized by higher greatest length, medial length, smallest breadth of the corpus, and greatest breadth of the distal end of the femur compared with Lohmann White (LW) hens. Dimensions of the tibia greatest length, axial length, smallest breadth of the corpus, greatest breadth of the distal end and greatest depth of the distal end in LB hens were also significantly (P < 0.05) higher than those in LW hens. Conclusions. The results showed that the genotype of laying hens tested after the laying period influenced carcass weight and muscle percentage, as well as differentiated the birds in terms of dimensions of individual segments of the digestive tract, femur, and tibia bones. Implications. The results of this research may be useful for consumers of laying hen carcasses and people interested in poultry anatomy. [ABSTRACT FROM AUTHOR]

There are some limitations to using the body condition score (BCS) for client education to prevent obesity, hyperlipidemia-related diseases, and orthopedic diseases in dogs because it is hard to quantify in detail. Especially in small dogs, patellar luxation is a common orthopedic disease that is related to obesity and the hind leg muscle. In this pilot study, the author evaluated the thorax/thigh circumference ratio as a prognostic evaluation index, along with the BCS, for assessing patellar dislocation and other hyperlipidemia-related diseases and states such as hypertriglyceridemia and obesity-related orthopedic disease in small dogs. Eleven client-owned dogs were selected randomly among patients that visited Bundang New York Animal Hospital, South Korea from June 2021 to August 2024. According to the results, triglycerides (TG) showed a negative correlation with thorax/thigh value (R = −0.585, p-value = 0.059) and a strong positive correlation with thigh circumference (R = 0.749, p-value = 0.008). Total cholesterol (TC) showed a strong positive correlation with thigh circumference (R = 0.776, p-value = 0.005), whereas the thorax/thigh value showed a negative correlation with the medial patella luxation (MPL) grade with low significance (R = −0.343, p-value = 0.302). These data indicate that thigh circumference can be an excellent negative indicator for hyperlipidemia and thorax/thigh value shows no correlation with medial patella luxation, which has many factors such as varus and trochlear groove. Despite the limitations of this study due to the small sample size, this pilot study is significant as it is the first trial to introduce a new indicator for monitoring hyperlipidemia at home by using a simple tape measure. Also, the author reviews molecular pathways including the ApoA-1, ApoE, and LPL genes, which are related to hyperlipidemia, to explain the results. [ABSTRACT FROM AUTHOR]

Reciprocal inhibition (RI) between leg muscles is crucial for smooth movement. Pedaling is a rhythmic movement that can increase RI in healthy individuals. Transcutaneous spinal cord stimulation (tSCS) stimulates spinal neural circuits by targeting the afferent fibers. Pedaling with simultaneous tSCS may modulate the plasticity of the spinal neural circuit and alter neural activity based on movement and muscle engagement. This study investigated the RI changes after pedaling and tSCS and determined the phase of pedaling in which tSCS should be applied for optimal RI modulation in healthy individuals. Eleven subjects underwent three interventions: pedaling combined with tSCS during the early phase of lower extension (phase 1), pedaling combined with tSCS during the late phase of lower flexion (phase 4) of the pedaling cycle, and pedaling combined with sham tSCS. The RI from the tibialis anterior to the soleus muscle was assessed before, immediately after, 15 min, and 30 min after the intervention. RI increased immediately after phase 4 and pedaling combined with sham tSCS, whereas no changes were observed after phase 1. These results demonstrate that tSCS modulates RI changes induced by pedaling in a stimulus phase-dependent manner in healthy individuals. However, the mechanism involved in this intervention needs to be explored to achieve higher efficacy. [ABSTRACT FROM AUTHOR]

When exposed to a predictable external perturbation, humans typically generate anticipatory postural adjustments (APAs) to minimize potential body disturbance. After a single session of training, individuals demonstrated the ability to rely solely on an auditory cue to elicit appropriate APAs in response to an external postural perturbation. However, whether the generation of APAs requires directional specific training remains unclear. The aim of this study was to assess whether directional-specific training with auditory cues is necessary for the generation of appropriate APA responses. Ten young adults were exposed to external perturbations targeting either their left or right shoulders, with or without an auditory cue prior to the physical impact. Electromyography (EMG) activities of sixteen trunk and leg muscles and center-of-pressure (COP) displacements were recorded and analyzed during the anticipatory and compensatory phases of postural control. Outcome measures included the latencies and integrals of muscle activities, COP displacements, and indices of co-contraction and reciprocal activation of muscles. The results revealed that, after training with right-side perturbations accompanied by an auditory cue, young adults exhibited earlier and more efficient APA responses to right-side perturbations relying only on the auditory cue. Additionally, they displayed earlier APA responses in some muscles to left-side perturbations, although these responses were less efficient. Our findings suggest that young adults could generate effective APAs to external perturbations relying on an auditory cue after a single training session; however, these responses were directional specific. [ABSTRACT FROM AUTHOR]

Purpose: Muscle activation often occurs in muscles ipsilateral to a voluntarily activated muscle and to a greater extent after stroke. In this study, we measured muscle activation in non-target, ipsilateral leg muscles and used transcranial magnetic stimulation (TMS) to provide insight into whether corticomotor pathways contribute to involuntary activation. Materials and methods: Individuals with stroke performed unilateral isometric ankle dorsiflexion, ankle plantarflexion, knee extension, and knee flexion. To quantify involuntary muscle activation in non-target muscles, muscle activation was measured during contractions from the ipsilateral tibialis anterior (TA), medial gastrocnemius (MG), rectus femoris (RF), and biceps femoris (BF) and normalized to resting muscle activity. To provide insight into mechanisms of involuntary non-target muscle activation, TMS was applied to the contralateral hemisphere, and motor evoked potentials (MEPs) were recorded. Results: We found significant muscle activation in nearly every non-target muscle during isometric unilateral contractions. MEPs were frequently observed in non-target muscles, but greater non-target MEP amplitude was not associated with greater non-target muscle activation. Conclusions: Our results suggest that non-target muscle activation occurs frequently in individuals with chronic stroke. The lack of association between non-target TMS responses and non-target muscle activation suggests that non-target muscle activation may have a subcortical or spinal origin. Non-target muscle activation has important clinical implications because it may impair torque production, out-of-synergy movement, and muscle activation timing. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office 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.)

Quantitative muscle magnetic resonance imaging (qMRI) is a valuable methodology for assessing muscular injuries and neuromuscular disorders. Notably, muscle diffusion tensor imaging (DTI) gives insights into muscle microstructural and macrostructural characteristics. However, the long‐term reproducibility and robustness of these measurements remain relatively unexplored. The purpose of this prospective longitudinal cohort study was to assess the long‐term robustness and range of variation of qMRI parameters, especially DTI metrics, in the lower extremity muscles of healthy controls under real‐life conditions. Twelve volunteers (seven females, age 44.1 ± 12.1 years, body mass index 23.3 ± 2.0 kg/m2) underwent five leg muscle MRI sessions every 20 ± 4 weeks over a total period of 1.5 years. A multiecho gradient‐echo Dixon‐based sequence, a multiecho spin‐echo T2‐mapping sequence, and a spin‐echo echo planar imaging diffusion‐weighted sequence were acquired bilaterally with a Philips 3‐T Achieva MR System using a 16‐channel torso coil. Fifteen leg muscles were segmented in both lower extremities. qMRI parameters, including fat fraction (FF), water T2 relaxation time, and the diffusion metrics fractional anisotropy (FA) and mean diffusivity (MD), were evaluated. Coefficients of variance (wsCV) and intraclass correlation coefficients (ICCs) were calculated to assess the reproducibility of qMRI parameters. The standard error of measurement (SEM) and the minimal detectable change (MDC) were calculated to determine the range of variation. All tests were applied to all muscles and, subsequently, to each muscle separately. wsCV showed good reproducibility (≤ 10%) for all qMRI parameters in all muscles. The ICCs revealed excellent agreement between time points (FF = 0.980, water T2 = 0.941, FA = 0.952, MD = 0.948). Random measurement errors assessed by SEM and the MDC were low (< 12%). In conclusion, in this study, we showed that qMRI parameters in healthy volunteers living normal lives are stable over 18 months, thereby defining a benchmark for the expected range of variation over time. [ABSTRACT FROM AUTHOR]