Proteomic Profiling of Muscular Adaptations to Short-Term Concentric Versus Eccentric Exercise Training in Humans.

The molecular mechanisms underlying muscular adaptations to concentric (CON) and eccentric (ECC) exercise training have been extensively explored. However, most previous studies have focused on specifically selected proteins, thus, unable to provide a comprehensive protein profile and potentially missing the crucial mechanisms underlying muscular adaptation to exercise training. We herein aimed to investigate proteomic profiles of human skeletal muscle in response to short-term resistance training. Twenty young males were randomly and evenly assigned to two groups to complete a 4-week either ECC or CON training program. Measurements of body composition and physiological function of the quadriceps femoris were conducted both before and after the training. Muscle biopsies from the vastus lateralis of randomly selected participants (five in ECC and four in CON) of both before and after the training were analyzed using the liquid-chromatography tandem mass spectrometry in combination with bioinformatics analysis. Neither group presented a significant difference in body composition or leg muscle mass; however, muscle peak torque, total work, and maximal voluntary contraction were significantly increased after the training in both groups. Proteomics analysis revealed 122 differentially abundant proteins (DAPs; p value < 0.05 & fold change >1.5 or <0.67) in ECC, of which the increased DAPs were mainly related to skeletal muscle contraction and cytoskeleton and enriched specifically in the pentose phosphate pathway, extracellular matrix-receptor interaction, and PI3K-Akt signaling pathway, whereas the decreased DAPs were associated with the mitochondrial respiratory chain. One hundred one DAPs were identified in CON, of which the increased DAPs were primarily involved in translation/protein synthesis and the mitochondria respiratory, whereas the decreased DAPs were related to metabolic processes, cytoskeleton, and de-ubiquitination. In conclusion, the 4-week CON and ECC training resulted in distinctly different proteomic profiles, especially in proteins related to muscular structure and metabolism.

Nuclear-localized androgen receptor content following resistance exercise training is associated with hypertrophy in males but not females.

Androgen receptor (AR) content has been implicated in the differential response between high and low responders following resistance exercise training (RET). However, the influence of AR expression on acute skeletal muscle damage and whether it may influence the adaptive response to RET in females is poorly understood. Thus, the purpose of this exploratory examination was to 1) investigate changes in AR content during skeletal muscle repair and 2) characterize AR-mediated sex-based differences following RET. A skeletal muscle biopsy from the vastus lateralis was obtained from 26 healthy young men (n = 13) and women (n = 13) at baseline and following 300 eccentric kicks. Subsequently, participants performed 10 weeks of full-body RET and a final muscle biopsy was collected. In the untrained state, AR mRNA expression was associated with paired box protein-7 (PAX7) mRNA in males. For the first time in human skeletal muscle, we quantified AR content in the myofiber and localized to the nucleus where AR has been shown to trigger cellular outcomes related to growth. Upon eccentric damage, nuclear-associated AR (nAR) content increased (p < .05) in males and not females. Males with the greatest increase in cross-sectional area (CSA) post-RET had more (p < .05) nAR content than females with the greatest gain CSA. Collectively, skeletal muscle damage and RET increased AR protein, and both gene and hypertrophy measures revealed sex differences in relation to AR. These findings suggest that AR content but more importantly, nuclear localization, is a factor that differentiates RET-induced hypertrophy between males and females.

Time-of-day effects on ex vivo muscle contractility following short-term satellite cell ablation.

Muscle isometric torque fluctuates according to time-of-day with such variation owed to the influence of circadian molecular clock genes. Satellite cells (SCs), the muscle stem cell population, also express molecular clock genes with several contractile-related genes oscillating in a diurnal pattern. Currently, limited evidence exists regarding the relationship between SCs and contractility, although long-term SC ablation alters muscle contractile function. Whether there are acute alterations in contractility following SC ablation and with respect to the time-of-day is unknown. We investigated whether short-term SC ablation affected contractile function at two times of day and whether any such alterations led to different extents of eccentric contraction-induced injury. Using an established mouse model to deplete SCs, we characterized muscle clock gene expression and ex vivo contractility at two times-of-day (morning: 0700 and afternoon: 1500). Morning-SC+ animals demonstrated ∼25%-30% reductions in tetanic/eccentric specific forces and, after eccentric injury, exhibited ∼30% less force-loss and ∼50% less dystrophinnegative fibers versus SC- counterparts; no differences were noted between Afternoon groups (Morning-SC+: -5.63 ± 0.61, Morning-SC-: -7.93 ± 0.61; N/cm2; P < 0.05) (Morning-SC+: 32 ± 2.1, Morning-SC-: 64 ± 10.2; dystrophinnegative fibers; P < 0.05). As Ca++ kinetics underpin force generation, we also evaluated caffeine-induced contracture force as an indirect marker of Ca++ availability and found similar force reductions in Morning-SC+ vs. SC- mice. We conclude that force production is reduced in the presence of SCs in the morning but not in the afternoon, suggesting that SCs may have a time-of-day influence over contractile function.NEW & NOTEWORTHY Muscle isometric torque fluctuates according to time-of-day with such variation owed to molecular clock regulation. Satellite cells (SCs) have recently demonstrated diurnal characteristics related to muscle physiology. In our work, force production was reduced in the presence versus absence of SCs in the morning but, not in the afternoon. Morning-SC+ animals, producing lower force, sustained lesser degrees of injury versus SC- counterparts. One potential mechanism underpinning lower forces produced appears to be lower calcium availability.

Pain quality patterns in delayed onset muscle soreness of the lower back suggest sensitization of fascia rather than muscle afferents: a secondary analysis study.

Delayed onset muscle soreness (DOMS) of the lower back is considered a surrogate for acute low back pain (aLBP) in experimental studies. Of note, it is often unquestioningly assumed to be muscle pain. To date, there has not been a study analyzing lumbar DOMS in terms of its pain origin, which was the aim of this study. Sixteen healthy individuals (L-DOMS) were enrolled for the present study and matched to participants from a previous study (n = 16, L-PAIN) who had undergone selective electrical stimulation of the thoracolumbar fascia and the multifidus muscle. DOMS was induced in the lower back of the L-DOMS group using eccentric trunk extensions performed until exhaustion. On subsequent days, pain on palpation (100-mm analogue scale), pressure pain threshold (PPT), and the Pain Sensation Scale (SES) were used to examine the sensory characteristics of DOMS. Pain on palpation showed a significant increase 24 and 48 h after eccentric training, whereas PPT was not affected (p > 0.05). Factor analysis of L-DOMS and L-PAIN sensory descriptors (SES) yielded a stable three-factor solution distinguishing superficial thermal ("heat pain ") from superficial mechanical pain ("sharp pain") and "deep pain." "Heat pain " and "deep pain" in L-DOMS were almost identical to sensory descriptors from electrical stimulation of fascial tissue (L-PAIN, all p > 0.679) but significantly different from muscle pain (all p < 0.029). The differences in sensory description patterns as well as in PPT and self-reported DOMS for palpation pain scores suggest that DOMS has a fascial rather than a muscular origin.

Usp20 deletion promotes eccentric cardiac remodeling in response to pressure overload and increases mortality.

Left ventricular hypertrophy (LVH) caused by chronic pressure overload with subsequent pathological remodeling is a major cardiovascular risk factor for heart failure and mortality. The role of deubiquitinases in LVH has not been well-characterized. To define if the deubiquitinase ubiquitin-specific peptidase 20 (USP20) regulates LVH, we subjected USP20 knockout (KO) and cognate wild type (WT) mice to chronic pressure overload by transverse aortic constriction (TAC) and measured changes in cardiac function by serial echocardiography followed by histological and biochemical evaluations. USP20-KO mice showed severe deterioration of systolic function within 4-weeks of TAC compared to WT cohorts. Both USP20-TAC and WT-TAC cohorts presented cardiac hypertrophy following pressure overload. However, USP20-KO-TAC mice showed an increase in cardiomyocyte length and developed maladaptive eccentric hypertrophy, a phenotype generally observed with volume-overload states and decompensated heart failure. In contrast, WT-TAC mice displayed increase in cardiomyocyte width, producing concentric remodeling that is characteristic of pressure overload. In addition, cardiomyocyte apoptosis, interstitial fibrosis and mouse mortality were augmented in USP20-KO-TAC compared to WT-TAC mice. Quantitative mass spectrometry of LV tissue revealed that the expression of sarcomeric myosin heavy chain 7 (MYH7), a fetal gene normally upregulated during cardiac remodeling was significantly reduced in USP20-KO after TAC. Mechanistically, we identified increased degradative lysine-48 polyubiquitination of MYH7 in USP20-KO hearts indicating that USP20-mediated deubiquitination likely prevents protein degradation of MYH7 during pressure overload. Our findings suggest that USP20-dependent signaling pathways regulate the layering pattern of sarcomeres to suppress maladaptive remodeling during chronic pressure overload and prevent cardiac failure.

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.

Cell-free DNA kinetics in response to muscle-damaging exercise: A drop jump study.

A significant increase in circulating cell-free DNA (cfDNA) occurs with physical exercise, which depends on the type of exertion and the duration. The aims of this study were as follows: (1) to investigate the time course of cfDNA and conventional markers of muscle damage from immediately after to 96 h after muscle-damaging exercise; and (2) to investigate the relationship between cfDNA and indicators of primary (low-frequency fatigue and maximal voluntary isometric contraction) and secondary (creatine kinase and delayed-onset muscle soreness) muscle damage in young healthy males. Fourteen participants (age, 22 ± 2 years; weight, 84.4 ± 11.2 kg; height, 184.0 ± 7.4 cm) performed 50 intermittent drop jumps at 20 s intervals. We measured cfDNA and creatine kinase concentrations, maximal voluntary isometric contraction torque, low-frequency fatigue and delayed-onset muscle soreness before and at several time points up to 96 h after exercise. Plasma cfDNA levels increased from immediately postexercise until 72 h postexercise (P < 0.01). Elevation of postexercise cfDNA was correlated with both more pronounced low-frequency fatigue (r = -0.52, P = 3.4 × 10-11) and delayed-onset muscle soreness (r = 0.32, P = 0.00019). Levels of cfDNA change in response to severe primary and secondary muscle damage after exercise. Levels of cfDNA exhibit a stronger correlation with variables related to primary muscle damage than to secondary muscle damage, suggesting that cfDNA is a more sensitive marker of acute loss of muscle function than of secondary inflammation or damaged muscle fibres.

Eccentric exercise before a 90 min exposure at 24,000 ft increases decompression strain depending on body region but not total muscle mass recruited.

Eccentric upper-body exercise performed 24 h prior to high-altitude decompression has previously been shown to aggravate venous gas emboli (VGE) load. Yet, it is unclear whether increasing the muscle mass recruited (i.e., upper vs. whole-body) during eccentric exercise would exacerbate the decompression strain. Accordingly, this study aimed to investigate whether the total muscle mass recruited during eccentric exercise influences the decompression strain. Eleven male participants were exposed to a simulated altitude of 24,000 ft for 90 min on three separate occasions. Twenty-four hours before each exposure, participants performed one of the following protocols: (i) eccentric whole-body exercise (ECCw; squats and arm-cycling exercise), (ii) eccentric upper-body exercise (ECCu; arm-cycling), or (iii) no exercise (control). Delayed onset muscle soreness (DOMS) and isometric strength were evaluated before and after each exercise intervention. VGE load was evaluated at rest and after knee- and arm-flex provocations using the 6-graded Eftedal-Brubakk scale. Knee extensor (-20 ± 14%, P = 0.001) but not elbow flexor (-12 ± 18%, P = 0.152) isometric strength was reduced 24 h after ECCw. ECCu reduced elbow flexor isometric strength at 24 h post-exercise (-18 ± 10%, P < 0.001). Elbow flexor DOMS was higher in the ECCu (median 6) compared with ECCw (5, P = 0.035). VGE scores were higher following arm-flex provocations in the ECCu (median (range), 3 (0-4)) compared with ECCw (2 (0-3), P = 0.039) and control (0 (0-2), P = 0.011), and in ECCw compared with control (P = 0.023). VGE were detected earlier in ECCu (13 ± 20 min) compared with control (60 ± 38 min, P = 0.021), while no differences were noted between ECCw (18 ± 30 min) and control or ECCu. Eccentric exercise increased the decompression strain compared with control. The VGE load varied depending on the body region but not the total muscle mass recruited. HIGHLIGHTS: What is the central question of this study? Does exercise-induced muscle damage (EIMD) resulting from eccentric exercise influence the presence of venous gas emboli (VGE) during a 90 min continuous exposure at 24,000 ft? What is the main finding and its importance? EIMD led to an earlier manifestation and greater VGE load compared with control. However, the decompression strain was dependent on the body region but not the total muscle mass recruited.

Joint synergy and muscle activity in the motion of the ankle-foot complex.

The movement of the ankle-foot complex joints is coupled as a result of various physiological and physical constraints. This study introduces a novel approach to the analysis of joint synergies and their physiological basis by focusing on joint rotational directions and the types of muscle contractions. We developed a biomimetic model of the ankle-foot complex with seven degrees of freedom, considering the skeletal configuration and physiological axis directions. Motion capture experiments were conducted with eight participants performing dorsiflexion and plantarflexion in open-chain states, as well as various walking tasks in closed-chain states, across different ground inclinations (±10, ±5, 0 deg) and walking speeds (3 and 4 km h-1). Hierarchical cluster analysis identified joint synergy clusters and motion primitives, revealing that in open-chain movements, plantarflexion of the ankle, tarsometatarsal and metatarsophalangeal joints exhibited synergy with the inversion of the remaining joints in the complex; meanwhile, dorsiflexion was aligned with eversion. During closed-chain movements, the synergies grouping was exchanged in the subtalar, talonavicular and metatarsophalangeal joints. Further analysis showed that in open-chain movements, synergy patterns influenced by multi-joint muscles crossing oblique joint axes contribute to foot motion. In closed-chain movements, these changes in synergistic patterns enhance the propulsion of the center of mass towards the contralateral leg and improve foot arch compliance, facilitating human motion. Our work enhances the understanding of the physiological mechanisms underlying synergistic motion within the ankle-foot complex.

Silicon eccentric shell nanoparticles fabricated by template-assisted deposition for Mie magnetic resonances enhanced light confinement.

We report a structure of silicon eccentric shell particles array, fabricated by the SiO2particles monolayer array assisted deposition of amorphous Si, for high-efficiency light confinement. The SiO2particles monolayer array is tailored to regulate its interparticle distance, followed by silicon film deposition to obtain silicon eccentric shell arrays with positive and negative off-center distancee. We studied the Mie resonances of silicon solid sphere, concentric shell, eccentric shell and observed that the eccentric shell with positive off-centeresupports superior light confinement because of the enhanced Mie magnetic resonances. Spectroscopic measurements and finite difference time domain simulations were conducted to examine the optical performance of the eccentric shell particles array. Results show that the Mie magnetic resonance wavelength can be easily regulated by the size of the inner void of the silicon shell to realize tunable enhanced light confinement. It was found silicon shell withD= 460/520 nm offered high enhanced light absorption efficiency at wavelength ofλ= 830 nm, almost beyond the bandgap of the amorphous silicon.

Effects of Combined Endurance and Resistance Eccentric Training on Muscle Function and Functional Performance in Patients With Chronic Obstructive Pulmonary Disease: Randomized Controlled Trial.

OBJECTIVE: To evaluate the adherence to treatment and efficacy of an eccentric-based training (ECC) program on peripheral muscle function and functional exercise capacity in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Prospective, assessor-blinded, randomized controlled trial. SETTING: The cardiopulmonary rehabilitation unit of a tertiary subacute referral center. PARTICIPANTS: Thirty (N=30) stable inpatients (mean age 68±8 years; FEV1 44±18% of predicted) with COPD were included in the study. INTERVENTIONS: Inpatients were randomly assigned to 4 weeks of a combined endurance and resistance ECC (n=15) or conventional training (CON; n=15). MAIN OUTCOME MEASURES: Quadriceps peak torque (PT) was the primary outcome measure for muscle function. Rate of force development (RFD), muscle activation and quality (quadriceps PT/leg lean mass), 6-min walk distance (6MWD), 4-meter gait speed (4mGS), 10-meter gait speed, 5-repetition sit-to-stand (5STS), dyspnea rate, and mortality risk were the secondary outcomes. Evaluations were performed at baseline and repeated after 4 weeks and 3 months of follow-up. RESULTS: Quadriceps PT, RFD, and muscle quality improved by 17±23% (P<.001), 19±24%, and 16±20% (both P<.05) within the ECC group. Besides, a significant between-group difference for RFD (56±94 Nm/s, P=.038) was found after training. Both groups showed clinically relevant improvements in 6MWD, 4mGS, dyspnea rate, and mortality risk, with no significant differences between groups. CONCLUSION: Combined endurance and resistance ECC improved lower limbs muscle function compared with CON in inpatients with COPD. In contrast, ECC did not further improve functional performance, dyspnea, and mortality risk. ECC may be of particular benefit to effect on skeletal muscle function in patients with COPD.

Pulsed electromagnetic fields attenuate human musculocutaneous nerve damage induced by biceps eccentric contractions.

Pulsed electromagnetic field (PEMF) therapy, a noninvasive treatment, has shown promise in mitigating nerve damage. However, unaccustomed exercises, such as eccentric contractions (ECCs), can damage both muscle and nerve tissue. This study investigated whether magnetic stimulation (MS) with PEMF could aid in nerve recovery after ECCs in the elbow flexors. Twenty participants were randomly assigned to either a control (CNT) or an MS group. Following ECCs, we measured the latency of the M-wave in the musculocutaneous nerve as an indicator of nerve function. Additionally, isometric torque, range of motion, and muscle pain were assessed for muscle function. Interestingly, only the CNT group exhibited a significant increase in latency on Day 2 (p < 0.05). The MS group, on the other hand, displayed an earlier recovery trend in isometric torque, range of motion, and muscle soreness. Notably, muscle soreness significantly decreased immediately after MS treatment compared to pretreatment levels. These findings suggest that MS treatment can effectively attenuate nerve damage induced by ECCs exercise.

Strength and power adaptations of the upper body following 20 training sessions on an eccentric arm-crank ergometer.

PURPOSE: Eccentric strength training is an innovative and promising approach to improve exercise performance. However, most eccentric training studies in the past were performed with a focus on the lower extremities. The present study aimed to test the feasibility and effects on strength and power adaptations of a structured upper-body eccentric training program. METHODS: Fourteen (median age (Q1-Q3) 29 years (27-32); 9 females, 5 males) healthy, regularly exercising individuals performed 20 progressive training sessions (2-3 sessions/week at 20-50% peak power for 8-14 min) on a symmetric eccentric arm-crank ergometer. Before and after the intervention, anaerobic peak power (PP) and maximal concentric aerobic power output (POmax) on an arm-crank ergometer as well as the one repetition maximum (1RM) for bench press were determined as main outcome parameters. A p-value ≤ 0.05 was considered statistically significant. RESULTS: Significant improvements in PP (+ 4% (1-8), p = 0.007), POmax (+ 6% (0-8); p = 0.01), and 1RM (+ 12% (10-17); p < 0.001) were found. Exercise intensity was relatively low at 64% (55-70) of maximum heart rate. CONCLUSIONS: Twenty progressive training sessions on a symmetric arm-crank ergometer are effective in inducing significant aerobic and anaerobic performance and strength improvements in the upper body. This intervention is safe and feasible, and can be performed at relatively low cardiovascular intensities. Therefore, this training method offers an interesting approach from elite sports to rehabilitation.

Temporal tracking of cysteine 34 oxidation of plasma albumin as a biomarker of muscle damage following a bout of eccentric exercise.

PURPOSE: Exercise-induced muscle damage (EIMD) results in the generation of reactive oxygen species (ROS), but little is known about the temporal profile of change in ROS post-EIMD and how ROS levels relate to the onset of and recovery from EIMD. Our primary aim was to examine the effect of EIMD on the pattern of change in the blood level of thiol-oxidised albumin, a marker of oxidative stress. METHODS: Seven male participants were subjected on separate days to eccentric muscle contraction to cause EIMD or a no-exercise condition. After each session, the participants collected daily dried blood spots to measure thiol-oxidised albumin and returned to the laboratory every 2 days for the assessment of indirect markers of EIMD, namely maximal voluntary contraction (MVC), delayed onset muscle soreness (DOMS), creatine kinase (CK), and myoglobin. RESULTS: Eccentric exercise resulted in a significant decrease in MVC and increase in DOMS, CK, myoglobin, and thiol-oxidised albumin with the latter reaching above baseline level within 24-48 h post-exercise. All the markers of EIMD returned to baseline level within 6 days post-exercise, but not the level of thiol-oxidised albumin which remained elevated for 10 days after exercise. There was a moderate correlation between changes in thiol-oxidised albumin and DOMS, but no significant relationship between any other markers of muscle damage. CONCLUSION: The levels of thiol-oxidised albumin increase in response to EIMD and remain elevated for several days post-exercise. The temporal pattern of change in the level of thiol-oxidised albumin suggests that this may be a useful biomarker of muscle repair post-EIMD.

Downhill running increases markers of muscle damage and impairs the maximal voluntary force production as well as the late phase of the rate of voluntary force development.

PURPOSE: To examined the time-course of the early and late phase of the rate of voluntary force development (RVFD) and muscle damage markers after downhill running. METHODS: Ten recreational runners performed a 30-min downhill run at 10 km h-1 and -20% (-11.3°) on a motorized treadmill. At baseline and each day up to 4 days RVFD, knee extensors maximum voluntary isometric force (MVIC), serum creatine kinase (CK) concentration, quadriceps swelling, and soreness were assessed. The early (0-50 ms) and late (100-200 ms) phase of the RVFD, as well as the force developed at 50 and 200 ms, were also determined. RESULTS: MVIC showed moderate decrements (p < 0.05) and recovered after 4 days (p > 0.05). Force at 50 ms and the early phase were not impaired (p > 0.05). Conversely, force at 200 ms and the late phase showed moderate decrements (p < 0.05) and recovered after 3 and 4 days, respectively (p > 0.05). CK concentration, quadriceps swelling, and soreness increased (p < 0.05) were overall fully resolved after 4 days (p > 0.05). CONCLUSION: Downhill running affected the knee extensors RVFD late but not early phase. The RVFD late phase may be used as an additional marker of muscle damage in trail running.

Effects of lunges inserted in walking (eccentric walking) on lower limb muscle strength, physical and cognitive function of regular walkers.

INTRODUCTION: Walking is a popular exercise but does not increase lower limb muscle strength and balance. We hypothesized that muscle strength, physical and cognitive function would be improved by inserting lunges in conventional walking. METHODS: Eleven regular walkers (54-88 years) who had more than 5000 steps in exercise walking a day at least 5 days a week participated in this study. They walked as usual for the first 4 weeks and included lunges and descending stairs or slope walking (i.e., eccentric walking) for the next 8 weeks. The steps of eccentric walking were gradually increased from 100 to 1000 steps per week over 8 weeks. RESULTS: The average steps per day were 10,535 ± 3516 in the first 4 weeks, and 10,118 ± 3199 in the eccentric walking period without a significant difference. No significant changes in maximal voluntary isometric contraction torque of the knee extensors (MVC), 30-s chair stand (CS), 2-min step, balance assessed by center of pressure movement area with eyes close, sit and reach, a digit symbol substitution test (DSST) for cognitive function were observed in the first 4 weeks. However, significant (P < 0.05) improvements were evident in MVC (18.6 ± 15.7%), CS (24.2 ± 17.3%), balance ( - 45.3 ± 34.5%), and DSST (20.8 ± 16.7%) from weeks 4 to 12. Serum complement component 1q concentration decreased (P < 0.05) from weeks 4 to 12, although no changes in serum glucose, triglyceride, and cholesterol concentrations were observed. CONCLUSION: These results supported the hypothesis, and suggest that eccentric walking provides effects that are not achieved by conventional walking.

Left Ventricular Geometric Pattern Impacts QT Dispersion in Males Athletes and Sedentary Men.

AIM: To (1) compare QT dispersion (QTd) and echocardiographic features between athletes with concentric left ventricular (LV) hypertrophy, athletes with eccentric LV hypertrophy, and sedentary controls with a normal LV geometric pattern and (2) quantify associations between QTd and echocardiographic features within these groups. METHODS: Male athletes competing in different sports and sedentary men were stratified into groups according to their LV geometric pattern. These groups included eccentric LV hypertrophy (LV index > 115 g/m2, relative wall thickness [RWT] < 0.42) consisting of 38 athletes, concentric LV hypertrophy (LV index > 115 g/m2, RWT > 0.42) consisting of 40 athletes, and normal LV geometric pattern (LV index < 115 g/m2, RWT < 0.42) consisting of 40 sedentary controls. Following a cross-sectional design, participants underwent electrocardiographic (ECG) and echocardiographic screening. Data were compared between groups using one-way analyses of variance with Bonferroni post hoc tests. Associations between corrected QTd and echocardiographic variables were quantified using Pearson correlations. RESULTS: Alongside structural disparities between groups, corrected QTd was significantly (p < 0.001) lower in athletes with eccentric LV hypertrophy compared to athletes with concentric LV hypertrophy and sedentary controls. Significant, moderate-to-very-large correlations were found between corrected QTd and interventricular septal wall thickness in athletes with concentric (r = 0.416, p = 0.008) or eccentric LV hypertrophy (r = 0.734, p < 0.001), and sedentary controls (r = 0.464, p = 0.003). CONCLUSION: The provided comparative and relationship data may inform the development of more precise approaches for ECG and echocardiographic screening in athletes, particularly in those with concentric LV hypertrophy who may be at greater risk for developing prolonged QTd.

Adaptive Force of hamstring muscles is reduced in patients with knee osteoarthritis compared to asymptomatic controls.

BACKGROUND: Quadriceps strength deficits are known for patients with knee osteoarthritis (OA), whereas findings on hamstrings are less clear. The Adaptive Force (AF) as a special neuromuscular function has never been investigated in OA before. The maximal adaptive holding capacity (max. isometric AF; AFisomax) has been considered to be especially vulnerable to disruptive stimuli (e.g., nociception). It was hypothesized that affected limbs of OA patients would show clear deficits in AFisomax. METHODS: AF parameters and the maximal voluntary isometric contraction (MVIC) of hamstrings were assessed bilaterally comparing 20 patients with knee OA (ART) vs. controls (CON). AF was measured by a pneumatically driven device. Participants were instructed to maintain a static position despite an increasing load of the device. After reaching AFisomax, the hamstrings merged into eccentric action whereby the force increased further to the maximum (AFmax). MVIC was recorded before and after AF trials. Mixed ANOVA was used to identify differences between and within ART and CON (comparing 1st and 2nd measured sides). RESULTS: AFisomax and the torque development per degree of yielding were significantly lower only for the more affected side of ART vs. CON (p ≤ 0.001). The percentage difference of AFisomax amounted to - 40%. For the less affected side it was - 24% (p = 0.219). MVIC and AFmax were significantly lower for ART vs. CON for both sides (p ≤ 0.001). Differences of MVIC between ART vs. CON amounted to - 27% for the more, and - 30% for the less affected side; for AFmax it was - 34% and - 32%, respectively. CONCLUSION: The results suggest that strength deficits of hamstrings are present in patients with knee OA possibly attributable to nociception, generally lower physical activity/relief of lower extremities or fear-avoidance. However, the more affected side of OA patients seems to show further specific impairments regarding neuromuscular control reflected by the significantly reduced adaptive holding capacity and torque development during adaptive eccentric action. It is assumed that those parameters could reflect possible inhibitory nociceptive effects more sensitive than maximal strengths as MVIC and AFmax. Their role should be further investigated to get more specific insights into these aspects of neuromuscular control in OA patients. The approach is relevant for diagnostics also in terms of severity and prevention.

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.

Effects of a horizontal speed deceleration training programme on measures of physical fitness in youth male handball players.

This study examined the effects of an 8-week horizontal speed deceleration training (HSDT) programme in combination with regular handball-specific training as compared with handball-specific training only in measures of physical fitness in male youth handball players. Thirty-nine players were randomly assigned to either an HSDT group (n = 18; 15.55 ± 0.24 years) or an active-control group (CG; n = 21; 14.59 ± 0.23 years). The results showed significant and large between-group differences at post-test in countermovement jump, change-of-direction speed, and repeated sprint ability (RSA) (all p < 0.01; d = 2.04 and 1.37, 1.39, 1.53, and 1.53 for the CMJ, 505 CoD, RSAbest, RSAaverage, and RSAtotal performances, respectively). The post-hoc-analysis demonstrated significant and large improvements in all measures of physical fitness in the HSDT group (∆2.49% to 16,25%; d = 1.01 to 1,70; all p < 0,01). The CG, however, failed to reach any significant difference in all measures of physical fitness ((∆0.31% to 1.98%; d = 0.15 to 0.22; p = 0.379; p > 0.05). To summarise, an 8-week in-season HSDT programme alongside regular handball-specific training yielded positive effects on various performance measures including jumping ability, CoD speed, and RSA, when compared to handball-specific training alone. These results highlight the potential benefits of integrating HSDT into the training regimen of youth handball athletes during the competitive season.