A three filament mechanistic model of musculotendon force and impedance.

The force developed by actively lengthened muscle depends on different structures across different scales of lengthening. For small perturbations, the active response of muscle is well captured by a linear-time-invariant (LTI) system: a stiff spring in parallel with a light damper. The force response of muscle to longer stretches is better represented by a compliant spring that can fix its end when activated. Experimental work has shown that the stiffness and damping (impedance) of muscle in response to small perturbations is of fundamental importance to motor learning and mechanical stability, while the huge forces developed during long active stretches are critical for simulating and predicting injury. Outside of motor learning and injury, muscle is actively lengthened as a part of nearly all terrestrial locomotion. Despite the functional importance of impedance and active lengthening, no single muscle model has all these mechanical properties. In this work, we present the viscoelastic-crossbridge active-titin (VEXAT) model that can replicate the response of muscle to length changes great and small. To evaluate the VEXAT model, we compare its response to biological muscle by simulating experiments that measure the impedance of muscle, and the forces developed during long active stretches. In addition, we have also compared the responses of the VEXAT model to a popular Hill-type muscle model. The VEXAT model more accurately captures the impedance of biological muscle and its responses to long active stretches than a Hill-type model and can still reproduce the force-velocity and force-length relations of muscle. While the comparison between the VEXAT model and biological muscle is favorable, there are some phenomena that can be improved: the low frequency phase response of the model, and a mechanism to support passive force enhancement.

The impact of a 10-week Nordic hamstring exercise programme on hamstring muscle stiffness, a randomised controlled trial using shear wave elastography.

Hamstring strain injuries (HSIs) remain a burden with high prevalence rates. The Nordic Hamstring exercise (NHE) has been found to be effective in preventing HSIs. However, the preventive mechanisms are not fully understood. Changes in stiffness are postulated as a possible protective mechanism. Surprisingly, the effect of the NHE on the stiffness of different hamstring muscles has never been investigated before. Therefore, the aim of this Randomised controlled trial was to investigate the impact of a 10-week NHE programme on the eccentric strength and the shear wave velocity (proxy of stiffness) of the hamstrings. Thirty-six soccer players were randomly assigned to either the control or the experimental group. The experimental protocol consisted of the incorporation of a 10-week NHE programme within the normal training routine. The hamstring stiffness and eccentric strength were assessed before and after. Within-group analyses showed a significant increase in strength, only for the experimental group. However, no significant effect of the NHE was found on the stiffness of each hamstring muscle. A 10-week NHE programme does not affect hamstring stiffness, despite an increase in eccentric strength, indicating that the preventive mechanism of the NHE is probably not (co-)explained by alterations in hamstring muscle stiffness.

A comparison of individual force decline profiles during a fatiguing eccentric trunk flexion and extension protocol: a pilot study.

Introduction: Muscle fatigue, characterized by diminished force production and contraction sustainability, can impair muscle coordination and increase joint instability. Differing force profiles used in fatiguing tasks, such as prolonged eccentric trunk protocols, might provide insights into individualized strategies and resulting spinal stability. Thus, this study assessed individual differences in fatigue characteristics during an eccentric trunk flexion-extension protocol in a population of asymptomatic individuals. Methods: Twelve participants (2 f/10 m, 29 ± 4 years, 78.4 ± 16.9 kg, 1.76 ± 0.10 m) performed an eccentric trunk flexion and extension protocol on an isokinetic dynamometer (45° flexion to 10° extension; 60°/s), with final analysis on 8 participants for trunk flexion and 11 for trunk extension due to data exclusions. Participants engaged in a maximal all-out (AO) task for 2 min. Each participant's torque output (Nm) was assessed on a repetition-by-repetition basis, and smoothened by a moving average of 5 repetitions. Individual time profiles for reaching fatigue thresholds (10%, 15%, 20% and 30% reduction of initial torque output), and inter subject variability (by coefficient of variation, CV in %) were assessed throughout the AO task. Further, percentage torque reduction and variability were assessed at mid (1-minute) and end (2-minute) of task. Results: On average, for flexor and extensor muscles combined, participants reached a force reduction of 10% within 23.2 ± 19.1 s, of 15% within 44.9 ± 19.6 s, of 20% in 62.4 ± 26.3 s, and of 30% within 79.2 ± 21.8 s. The variability between individuals for the timepoint of reaching the defined torque thresholds was assessed by CV ranged between 23.4% and 103.8% for trunk flexor muscles, and between 28.4% and 56.5% for trunk extensor muscles. Discussion: A reduction of up to 20% was seen on average for all participants within 1-minute of eccentric trunk flexion and extension. Different inter-individual force output profiles were seen throughout the AO protocol, potentially related to physiological, skill-based, technical, adaptational, and/or motivational factors. The increase in fatigue resulted in a reduction in variability among individuals. A 2-minute protocol effectively induced pronounced fatigue, offering insights into individual force profiles and strategies.

Effects of a Manual Treatment on Lumbar Microcirculation and Tissue Stiffness Following Submaximal Eccentric Trunk Extensor Exercise: A Randomized Controlled Trial.

Recent studies have shown that the extramuscular connective tissue (ECT) is thickened and stiffened in delayed onset muscle soreness (DOMS). However, contrarily to the normal population, severe DOMS is rare in athletes or highly trained individuals. The present randomized, controlled trial therefore aimed to investigate pain as well as microcirculation and stiffness of the ECT and the erector spinae muscle following submaximal eccentric trunk extension exercise not causing DOMS. The effect of manual treatment by a therapist (myofascial release; MFR) on these parameters was to be studied. Trained healthy participants (n = 21; 31.3 ± 9.6 years; > 4 h exercise per week) performed submaximal eccentric exercise of the trunk extensors. One group was manually treated (n = 11), while the other group (n = 10) received placebo treatment with sham laser therapy. Stiffness of the ECT and the erector spinae muscle (shear wave elastography), microcirculation (white light and laser Doppler spectroscopy), palpation pain (100 mm visual analogue scale, VAS) and pressure pain threshold (indentometry, PPT) were assessed before (t0), 24 h (t24) and 48 h (t48) after conditions. Erector spinae muscle stiffness increased after eccentric exercise from t0 to t24 (0.875 m/s) and from t0 to t48 (0.869 m/s). After MFR, erector spinae muscle stiffness decreased in contrast to placebo treatment at t24 (-0.66 m/s), while ECT stiffness remained unchanged. Oxygen saturation increased (17-20.93%) and relative haemoglobin decreased (-9.1 - -12.76 AU) after eccentric exercise and MFR differed from placebo treatment at t48 (-3.71 AU). PPT differed after MFR from placebo treatment at t48 (20.69 N/mm), while VAS remained unchanged. Multiple linear regression showed that ECT stiffness and group membership predicted erector spinae muscle stiffness. MFR could have a positive effect on pain, microcirculation and muscle stiffness after submaximal eccentric exercise, suggesting better recovery, which needs to be confirmed by future work.

Modular Baseplate Augmentation: A Simple and Effective Method for Addressing Eccentric Glenoid Wear.

BACKGROUND: Augmented baseplates can be effective at addressing eccentric glenoid wear in reverse total shoulder arthroplasty (rTSA). However, these implants often come in a limited number of predetermined shapes that require additional reaming to ensure adequate glenoid seating. This typically involves complex instrumentation and can have a negative impact on implant stability. Modular baseplate augmentation based on intra-operative measurements may allow for more precise defect filling while preserving glenoid bone. The purpose of this investigation was to assess the stability of a novel ringed baseplate with modular augmentation in comparison to non-augmented standard and ringed baseplate designs. METHODS: In this biomechanical study, baseplate micromotion was tested for three constructs according to American Society for Testing and Materials (ASTM) guidelines. The constructs included a non-augmented curved baseplate, a non-augmented ringed baseplate and ringed baseplate with an 8 mm locking modular augmentation peg. The non-augmented constructs were mounted flush onto polyurethane (PU) foam blocks, while the augmented baseplate was mounted on a PU block with a simulated defect. Baseplate displacement was measured prior to and after 100,000 cycles of cyclic loading. RESULTS: Prior to cyclic loading, the non-augmented and augmented ringed baseplates both demonstrated significantly less micromotion than the non-augmented curved baseplate design (81.1 µm vs 97.2 µm vs 152.7 µm; p=0.009). After cyclic loading, both ringed constructs continued to have significantly less micromotion compared to the curved design (105.5 µm vs 103.2 µm vs 136.6 µm; p<0.001). The micromotion for both ringed constructs remained below the minimum threshold required for bony ingrowth (150 µm) at all time points. CONCLUSION: In the setting of a simulated glenoid defect, locked modular augmentation of a ringed baseplate does not result in increased baseplate micromotion when compared to full contact, non-augmented baseplates. This design offers a simple method for tailored baseplate augmentation that can match specific variations in glenoid anatomy, limiting the need for excessive reaming and ultimately optimizing the environment for long term implant stability. LEVEL OF EVIDENCE: Basic Science Study; Biomechanics.

Corrigendum: Effects of exercise treatment on functional outcome parameters in mid-portion Achilles tendinopathy: a systematic review.

[This corrects the article DOI: 10.3389/fspor.2023.1144484.].

Does the short-term learning effect impact vertical jump performance assessment on a portable force plate system?

One of the reoccurring questions that arises during the countermovement vertical jump (CVJ) assessment is whether the learning effect has an impact on the accuracy of the results obtained. Thus, the purpose of the present investigation was to examine the impact of the short-term learning effect on the assessment of lower-body neuromuscular performance characteristics when performed on a portable one-dimensional force plate system. Sixteen recreationally active college-age males volunteered to participate in the present study. Each participant completed four sets of three non-consecutive CVJs with no arm swing throughout a single day. Besides strong verbal encouragement, participants were constantly instructed to focus on pushing the ground as explosively as possible. Fourteen force-time metrics were selected for CVJ performance analysis purposes: eccentric and concentric peak and mean force and power, eccentric and concentric duration, contraction time, jump height, reactive strength index-modified, and countermovement depth. Repeated measures multivariate analysis of variance was used to examine statistically significant differences across four testing time points (p < 0.05). The results indicate an absence of any meaningful differences across four testing time points in force-time metrics of interest during both eccentric and concentric phases of the CVJ. Moreover, no differences were observed in CVJ outcome metrics such as countermovement depth, suggesting that the movement strategy tends to remain consistent. Overall, these findings reveal that CVJ test repeatability is not affected by the short-term learning effect and that data are stable at least within the scope of this study and within this population.

Relationship between sleep quality and quantity and lower-body neuromuscular performance characteristics in semi-professional male basketball players.

Sleep has been recognized as one of the most essential recovery methods necessary for achieving optimal performance. However, there is still a lack of scientific literature focused on examining its impact on one of the most prevalent skills in the game of basketball, the countermovement vertical jump (CVJ). Therefore, the purpose of the present study was to examine the relationship between sleep quality and quantity, and lower-body neuromuscular performance characteristics within a cohort of semi-professional male basketball players. Twenty-eight athletes competing in a first-tier regional league in Serbia volunteered to participate in this investigation. Upon arrival at the gym, all athletes completed the Pittsburgh Sleep Quality Index (PSQI) self-rated questionnaire. Immediately after completion of the PSQI, each athlete stepped on a force plate system and performed three maximum-effort CVJs with no arm swing. The following force-time metrics were obtained for the analysis: eccentric and concentric absolute and relative mean and peak force and power, vertical jump height, and reactive strength index-modified. Pearson product-moment correlation coefficients were used to examine the strength of the linear relationships between sleep quality and quantity and lower-body neuromuscular performance characteristics (p < 0.05). The results indicated that sleep quality appears to have a greater impact on the concentric than the eccentric phase of the CVJ (e.g., concentric mean force [r = -0.830; p < 0.001], relative concentric peak force [r = -0.466; p = 0.013, eccentric mean power (r = -0.162; p = 0.409)], while no significant relationship was found between sleep quantity and lower-body neuromuscular performance (e.g., concentric peak force [r = -0.055; p = 0.782], relative eccentric mean power [r = -0.301; p = 0.107]). Overall, these findings offer valuable insights into the importance of good sleep hygiene (e.g., efficiency, duration) in an athletic population, and can help practitioners develop more effective training and recovery programs.

Eccentric exercise-induced delayed onset trunk muscle soreness alters high-density surface EMG-torque relationships and lumbar kinematics.

We aimed to assess high-density surface electromyography (HDsEMG)-torque relationships in the presence of delayed onset trunk muscle soreness (DOMS) and the effect of these relationships on torque steadiness (TS) and lumbar movement during concentric/eccentric submaximal trunk extension contractions. Twenty healthy individuals attended three laboratory sessions (24 h apart). HDsEMG signals were recorded unilaterally from the thoracolumbar erector spinae with two 64-electrode grids. HDsEMG-torque signal relationships were explored via coherence (0-5 Hz) and cross-correlation analyses. Principal component analysis was used for HDsEMG-data dimensionality reduction and improvement of HDsEMG-torque-based estimations. DOMS did not reduce either concentric or eccentric trunk extensor muscle strength. However, in the presence of DOMS, improved TS, alongside an altered HDsEMG-torque relationship and kinematic changes were observed, in a contraction-dependent manner. For eccentric trunk extension, improved TS was observed, with greater lumbar flexion movement and a reduction in δ-band HDsEMG-torque coherence and cross-correlation. For concentric trunk extensions, TS improvements were observed alongside reduced thoracolumbar sagittal movement. DOMS does not seem to impair the ability to control trunk muscle force, however, perceived soreness induced changes in lumbar movement and muscle recruitment strategies, which could alter motor performance if the exposure to pain is maintained in the long term.

Eccentric Compression Behavior of Truss-Reinforced Cross-Shaped Concrete-Filled Steel Tubular Columns.

In the paper, the eccentric compression behavior of the truss-reinforced cross-shaped concrete-filled steel tubular (CCFST) column is investigated. A total of eighteen CCFST columns were tested under eccentric compression, and the key test variables included the reinforced truss node spacing (s = 140 mm and 200 mm), slenderness ratio (λ = 9.2, 16.6, and 23.1), and eccentricity ratio (η = 0, 0.08, and 0.15). The failure mode, deformation characteristic, stress distribution, strain distribution at the mid-span of the steel tube, and the eccentric compression bearing capacity were assessed. The results show that due to the addition of reinforced truss, the steel plates near the mid-span of eccentrically compressed CCFST columns experienced multi-wave buckling rather than single-wave buckling after the peak load was reduced to 85%, and the failure mode of concrete also changed from single-section to multi-section collapse failure. Comparisons were made with the unstiffened specimen. The ductility coefficient of the stiffened specimen with eccentricity ratios of 0.08-0.15 and node spacings of 140 mm~200 mm increased by 70~83%, approaching that of the multi-cell specimens with an increasing steel ratio of 1.8%. In addition, by comparing the test results with the calculation results of four domestic and international design codes, it was found that the Chinese codes CECS159-2018 and GB50936-2014, and the Eurocode 4 (2004) can be better employed to predict the compression bearing capacity of truss-reinforced CCFST columns.

No immediate change in systemic cytokines following an eccentric muscle training session in people with multiple sclerosis.

Background: Eccentric muscle contractions elicit distinct physiological responses, including modulation of the cytokine profile. Although relevant for rehabilitation, the effect of eccentric muscle training on the immune system has never been investigated in multiple sclerosis (MS). Objectives: Examine the immediate cytokine response of interleukin-4 (IL-4), IL-6, IL-10, IL-17a, interferon-gamma, and tumor necrosis factor-alpha after a moderate eccentric training session in individuals with MS. Additionally, further investigate the association between systemic cytokine levels at rest and clinical measures of mobility and lower limb functional strength. Design: Observational study. Methods: The first session included blood sampling for baseline cytokine measures. Subsequently, the participant completed a battery of clinical assessments related to mobility and lower limb strength, that is, the Timed-Up-and-Go Test, Five-Repetition-Sit-to-Stand-Test (5STS), Four-Square-Step-Test, and Two-Minute-Walk-Test. The second session included the eccentric exercise training session, followed by a second blood sampling to assess the acute cytokine response to the eccentric training bout. This session comprised 10 exercises concentrating on the strength of the trunk and lower extremities. Results: Twenty-seven people with MS (pwMS), with a mean age of 40.1 years, participated in the study. No difference was demonstrated in the cytokine concentration values between baseline and immediately after the eccentric training session. The 5STS explained 30.3% of the variance associated with interferon-gamma, 14.8% with IL-4, and 13.8% with IL-10. Conclusion: An eccentric training bout does not impact cytokine concentration in the blood and, consequently, does not boost a pro-inflammatory response, thus, it can be performed on pwMS in a rehabilitation setting.

A strength-lengthening exercise session doesn't affect inflammation markers in people with multiple sclerosis The article explores how a specific type of exercise, called eccentric muscle training, affects people with multiple sclerosis (MS). Eccentric muscle training involves exercises where the muscle lengthens under tension, like when you slowly lower a heavy object. This type of exercise is known for causing unique physical responses, including changes in certain proteins in the blood that help control the immune system and inflammation. The main goal of the study was to see if a session of eccentric muscle training would change the levels of these proteins, called cytokines, in the blood of people with MS immediately after exercise. The cytokines studied included IL-4, IL-6, IL-10, IL-17a, INF-γ, and TNF-α. These proteins are important because they help regulate inflammation and immune responses. The researchers also wanted to know if there was any connection between the levels of these proteins at rest and measures of mobility and leg strength. Twenty-seven people with MS took part in the study. Their average age was 40.1 years. In the first session, blood samples were taken to measure the baseline levels of these proteins, and various tests were conducted to assess mobility and leg strength. In the second session, participants completed an eccentric training session, and another blood sample was taken immediately after to see if there were any immediate changes in the protein levels. The results showed no significant differences in the protein levels before and after the exercise session. This suggests that a single session of eccentric muscle training does not cause an immediate inflammatory response in the blood. Therefore, this type of exercise can be safely included in rehabilitation programs for people with MS without the risk of causing harmful inflammation. Overall, the study supports the safety of eccentric muscle training for people with MS and provides valuable insights into its immediate effects on the immune system.

Well-Dispersed CsPbBr3@TiO2 Heterostructure Nanocrystals from Asymmetric to Symmetric.

Metal halide perovskites (MHPs) have undergone rapid development in the fields of solar cells, light diodes, lasing, photodetectors, etc. However, the MHPs still face significant challenges, such as poor stability and heterocompositing with other functional materials at the single nanoparticle level. Herein, the successful synthesis of well-dispersed CsPbBr3@TiO2 heterostructure nanocrystals (NCs) is reported, in which each heterostructure NC has only one CsPbBr3 with a precise anatase TiO2 coating ranging from asymmetric to symmetric. Due to the protection of anatase TiO2, CsPbBr3 shows dramatically improved chemical stability and photostability. More significantly, the synthesized CsPbBr3@TiO2 heterostructure NCs form a type II heterojunction, which strongly promoted efficient photogenerated carrier separation between anatase TiO2 and CsPbBr3, hence leading to improved optoelectronic activity. This study provides a robust avenue for synthesizing stable and highly efficient MHPs@metal oxide heterostructure NCs, paving the way for the practical application of all inorganic perovskites.

Effectiveness of Kinesiotherapy in the Treatment of Achilles Tendinopathy-A Narrative Review.

This narrative review of kinesiotherapy methods in the treatment of Achilles tendinopathy (AT) encompassed a diverse range of studies, including athletes and untrained people, healthy or injured, undergoing kinesiotherapy treatments. Most experimental studies (86%) reported results related to pain perception, 27% to the range of motion, and 27% to biomechanical assessment. However, the studies showed notable heterogeneity in the outcomes associated with the interventions, and, in this review of kinesiotherapy protocols for AT, a prominent observation emerged regarding their efficacy, suggesting a more favorable impact on pain and tendon stiffness management when comparing the measured parameters between the trained and untrained groups. The importance of tailoring the treatment approach based on the individual's athletic background and conditioning status is underscored. There is a need for personalized rehabilitation strategies in athletic populations. The average duration of kinesiotherapy in the treatment of tendinopathy was 15.3 weeks. This observation underscores the potential of kinesiotherapy interventions as a viable treatment option for individuals with Achilles tendon issues. These findings underscore the urgent need for further research to provide stakeholders with more comprehensive directions for future studies. The results may be helpful for doctors, physiotherapists, trainers, and researchers interested in this topic.

Design of Anti-Eccentric Load Sensor for Engineering Operation Early Warning Based on Particle Swarm Optimization.

The accuracy of aerial work platform weighing is essential for safety. However, in practice, the same weight placed at different locations on the platform can yield varying readings, which is a phenomenon known as eccentric load. Measurement errors caused by eccentric loads can lead to missed detections and false alarms in the vehicle safety system, seriously affecting the safety of aerial work. To overcome the influence of eccentric load, the current engineering practice relies on multiple measurements at multiple points and averaging the results to eliminate the eccentric load, which greatly increases the work intensity of workers. To address the aforementioned issues, this paper proposes a three-dimensional force/torque shear force compensation scheme based on bending torque and torsional torque for pressure. The goal is to ensure that the sensor on the aerial work vehicle platform can accurately measure the anti-eccentric load under single-point measurement conditions. A three-box structure anti-eccentric load-weighing sensor for the aerial work platform was designed. Its structure has the advantages of high mechanical strength and no radial effect, ensuring the safety of aerial work, improvement of measurement sensitivity, and enabling of real-time and accurate acquisition of force/torque in three directions. In order to further improve the measurement accuracy of 3D force/torque compensation, a particle swarm optimization algorithm was adopted to optimize the 3D force/torque shear force compensation, thereby improving the safety of engineering operations. Through the verification of a self-made testing platform, the anti-eccentric load sensor designed in this study can ensure that the measurement error of objects at any position on the platform is less than 1.5%, effectively improving the safety of high-altitude platform engineering operations.

Impact of Eccentric Exercise Interventions with Small and Large Ranges of Motion on Rat Skeletal Muscle Tissue and Muscle Force Production.

Eccentric training induces greater hypertrophy while causing more muscle damage than concentric training. This study examined the effects of small-range eccentric contractions (SR-ECCs) and large-range eccentric contractions (LR-ECCs) on muscle morphology, contractility, and damage in rats. Thirty male Fischer 344 rats were divided into five groups: small-range ECC single-bout (SR-ECCSB, n = 4), large-range ECC single-bout (LR-ECCSB, n = 4), SR-ECC intervention (SR-ECCIntv, n = 7), LR-ECC intervention (LR-ECCIntv, n = 8), and control (Cont, n = 7). These groups underwent transcutaneous electrical stimulation involving 80 ECCs twice a week for four weeks. The results indicated that the LR-ECCSB group had more Evans blue dye-positive fibers than other groups. The SR-ECCIntv group showed no increase in the mean myofiber cross-sectional area. However, Pax7+ and Ki67+ cells significantly increased in both ECCIntv groups compared to the Cont group, and the connective tissue area was significantly greater in the LR-ECCIntv than in others. Muscle force was lower in both ECCIntv groups compared to the Cont group. These findings suggest that SR-ECC intervention may induce a smaller increase in the number of fibers with a large myofiber cross-sectional area and satellite cell proliferation with less muscle damage and myofibrosis compared to LR-ECCs.

Pre-exercise cryotherapy reduces myoglobin and creatine kinase levels after eccentric muscle stress in young women.

Introduction: The aim of this study was to investigate the effect of pre-exercise whole-body cryotherapy (WBC) on muscle damage indicators following eccentric treadmill exercise in young women. Methods: Twenty-seven participants underwent two 1-h downhill treadmill runs, replicating 60% of their maximal oxygen uptake, with a 4-week intermission for recovery and treatment application. In this intermission, one group underwent 20 sessions of WBC, delivered five times a week at -120°C for 3 min each, while the comparison group received no such treatment. Markers of muscle injury-serum myoglobin concentration, creatine kinase and lactate dehydrogenase activity and also uric acid, and cell-free DNA concentration-were measured before and after downhill runs. Results: The study observed a notable reduction in post-exercise myoglobin and CK levels in the WBC group after the second running session. Discussion: The results suggest that WBC can have a protective effects against muscle damage resulting from eccentric exercise.

Acute effects of eccentric overload training with different loading doses in male sprinters.

Objective: The primary objective of this study was to investigate the immediate effects of two doses (Dose1 and Dose2,D1 and D2) of inertial Flywheel Eccentric Overload (FEOL), Eccentric Hook (EH), and High-intensity Half Squat (HHS) on muscle explosiveness in male sprinters. Methods: Twenty-one sub-elite male sprinters were randomly assigned to three groups: the FEOL group (n=7), the EH group (n=7), and the HSS group (n=7),Measurements of athletes' explosive jumps (CMJ, SJ, SLJ) heights, relative peak power indices, and 30-m sprint times were collected before and 6 min after the intervention. Results: At D1 loading dose, CMJ, SJ jump height, and relative peak power increased significantly (p < 0.05) after HHS training intervention, while there was no significant change in FEOL and EH training (p > 0.05). At D2 loading dose, CMJ, SJ jump height, and relative peak power increased significantly (p < 0.01) after FEOL and EH training intervention, but at D2HHS intervention, these indexes tended to decrease (p < 0.05). None of the three training protocols significantly improved SLJ performance (p > 0.05). CMJ vertical jump height and relative peak power were significantly higher after D2FEOL and D2EH interventions than after D1HHS (P < 0.05). Conclusion: D1HHS, D2FEOL and D2EH3 intervention methods can all improve the performance of sub-elite athletes in the 30-m test, CMJ test and SJ test. in the CMJ test, FEOL training demonstrated a higher acute augmentation effect compared to EH training.

Bioimpedance analysis for identifying new indicators of exercise-induced muscle damage.

A noninvasive, immediate, and convenient method for assessing muscle tissue status during exercise-induced muscle damage (EIMD) has not been established. This study was designed to assess and determine parameters suitable for measuring EIMD after eccentric exercise, using multi-frequency bioimpedance analysis (BIA). Thirty-five young male participants performed dumbbell exercises with their left arm, and their BIA parameters were measured at various time points up to 168 h post exercise using a multi-frequency BIA device. At all-time points, intra and extracellular water content was greater in the left arm than in the right arm, whereas the impedance, reactance, resistance, and phase angle were lower in the left arm than in the right arm. Established EIMD indices, such as maximal isometric voluntary contraction, were measured and used in correlational analyses. Only reactance was correlated with biomarkers, indicating muscle damage (r = - 0.56 to - 0.49). Furthermore, reactance was found to correlate well with indirect indicators of EIMD, suggesting that it may be a suitable marker for evaluating EIMD. However, the relationship with the limited evaluation indices employed in this study is constrained. Future studies should investigate the correlation between reactance and direct damage indicators, such as structural damage, observed in biopsies.

3Dimensional sonography for the diagnosis of congenital uterine anomalies in women with eccentric pregnancy implantation: a novel approach.

PURPOSE: The eccentric implantation of pregnancies in the upper lateral aspect of the uterine cavity is poorly defined clinically. The aim of the current study was to investigate whether differentiating between uterine anomalies that can lead to cavitary distortion has implications for the management of these pregnancies. METHODS: Eight cases of first-trimester eccentric pregnancy implantation within the endometrial cavity (study group) were retrospectively identified. For each woman in the study group, 10 women identified as having a first-trimester concentric pregnancy implantation during the first-trimester US examination were retrieved from our database (control group). After delivery or pregnancy demise, the presence of uterine anomalies was assessed by a 3D-US examination in all patients. RESULTS: In the study group patients, an increased incidence of uterine anomalies (50.0% vs. 8.8%, p = 0.007) was found, compared to the controls. In the study group, the eccentric location persisted in half of the pregnancies (n = 4; 50%), whereas the other half migrated to a more centric location within the endometrial cavity (n = 4; 50%). The follow-up examination showed that all the early pregnancy demises occurred in cases where the pregnancy persisted at the eccentric location. Uterine malformations were also detected in all these cases. CONCLUSION: The data point to a significantly higher incidence of uterine anomalies in patients diagnosed with eccentric pregnancy implantation within the endometrial cavity. These results advocate for the value of differentiating between eccentric pregnancies in non-anomalous versus anomalous uteri.