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Context: The purpose of the study was to develop normative ranges and standards for knee and shoulder isokinetic and anthropometric values. These standards can be qualitatively interpreted and allow practitioners to classify isokinetic and anthropometric values more objectively for university-level netball players. Design: Posttest only observational study design. All players were only evaluated once during the in-season to generate normative ranges. Methods: A total of 51 female players volunteered. Participants were evaluated on an isokinetic dynamometer at 60° per second to obtain knee-extensor and knee-flexor values as well as shoulder-flexor and shoulder-extensor values. A total of 16 anthropometric variables were collected including stature, body mass, 8 skinfolds, and 6 circumferences. Between-group differences were calculated to determine whether playing level was a differentiating factor in data. Results: Normative standards were developed for isokinetic parameters associated with the knee and shoulder joints as well as skinfolds and circumference measures. No statistically significant between-group differences were evident (χKruskal-Wallis²[2] = 3.96, P = .140). Conclusion: These standards can be used by coaches and practitioners to set attainable goals for individual players or those from secondary leagues, classify individual and team-based performances, and facilitate decision-making processes. [ABSTRACT FROM AUTHOR]

This study examined the effect of 6-week training to improve horizontal deceleration ability on sprint acceleration and countermovement jump (CMJ) neuromuscular performance (NMP) parameters. Twenty male soccer players were divided into the training (TRA), and the control (CON) group. Pre-and post-training players performed an acceleration-deceleration ability test (ADA) and a jump on a vertical axis dual force plate. ADA deceleration parameters were analysed using Kinovea Software. Distance-to-stop (DTS), time-to-stop (TTS), 20 m sprint time (t20 m), CMJ parameters were measured at pre-post-training. The largest improvement was determined in the TRA in the t20 m (effect size = 0.88). Despite the increase in the weight of the TRA, t20 m was shortened by 5.62% in TRA and 1.91% in CON. Deceleration ability was evaluated with CMJ eccentric parameters. While the percentage change of eccentric peak force differed between the groups, eccentric peak power (11.84 vs. 14.57 W·kg–1, ds: 0.72) and velocity (0.91 vs. 1.05 m.s–1, ds: 0.70) increased. Accordingly, it was determined that the improvement in CMJ eccentric and concentric peak velocity was due to speed-based power output. The training improved the maximum horizontal deceleration ability and confirmed that concentric peak velocity, as well as CMJ eccentric parameters, is an important NMP determinant of horizontal deceleration ability. [ABSTRACT FROM AUTHOR]

Purpose: To explore patterns of disease expression in Alagille syndrome (ALGS). Methods: Patients underwent ophthalmic examination, optical coherence tomography (OCT) imaging, fundus intravenous fluorescein angiography (IVFA), perimetry and full-field electroretinograms (ffERGs). An adult ALGS patient had multimodal imaging and specialized perimetry. Results: The proband (P1) had a heterozygous pathogenic variant in JAG1; (p.Gln410Ter) and was incidentally diagnosed at age 7 with a superficial retinal hemorrhage, vascular tortuosity, and midperipheral pigmentary changes. The hemorrhage recurred 15 months later. Her monozygotic twin sister (P2) had a retinal hemorrhage at the same location at age 11. Visual acuities for both patients were 20/30 in each eye. IVFA was normal. OCT showed thinning of the outer nuclear in the peripapillary retina. A ffERG showed normal cone-mediated responses in P1 (rod-mediated ERGs not documented), normal ffERGs in P2. Coagulation and liver function were normal. An unrelated 42-year-old woman with a de-novo pathogenic variant (p. Gly386Arg) in JAG1 showed a similar pigmentary retinopathy and hepatic vascular anomalies; rod and cone function was normal across large expanses of structurally normal retina that sharply transitioned to a blind atrophic peripheral retina. Conclusion: Nearly identical recurrent intraretinal hemorrhages in monozygotic twins with ALGS suggest a shared subclinical microvascular abnormality. We hypothesize that the presence of large areas of functionally and structurally intact retina surrounded by severe chorioretinal degeneration, is against a predominant involvement of JAG1 in the function of the neurosensory retina, and that instead, primary abnormalities of chorioretinal vascular development and/or homeostasis may drive the peculiar phenotypes. [ABSTRACT FROM AUTHOR]

With innovative portable force plate systems being widely implemented for lower-body neuromuscular performance assessment in an applied sports setting and the existing gap in the scientific literature regarding player performance during in-game competitive scenarios, the purpose of the present study was to compare changes in countermovement vertical jump (CVJ) performance pre-post a simulated 3×3 basketball tournament. Seven current or former members of a 3×3 national basketball team volunteered to participate in the present investigation. Upon completing standardized warm-up procedures, athletes stepped on a uni-axial force plate system sampling at 1,000 Hz and performed three maximal-effort CVJs with no arm swing. Then, the athletes proceeded to play a simulated 3×3 basketball tournament composed of two consecutive games, separated by a 15-min rest interval. Immediately following the completion of the second game, the identical CVJ testing procedures were repeated. Paired sample t-tests were used to examine prepost-tournament differences in nineteen CVJ performance metrics (p < 0.05). The results reveal that force-time metrics during both eccentric and concentric phases of the CVJ remain relatively unchanged pre-post simulated 3×3 basketball tournament. However, multiple force-time metrics within the eccentric phase of the CVJ changed by 12.1%-19.1% (e.g., eccentric peak power and peak velocity, eccentric duration), suggesting that the eccentric phase of CVJ might be responsive to performance stimulus to a greater extent than the concentric phase. Overall, these findings further support the importance of comprehensive CVJ analysis when intending to measure changes in neuromuscular performance. [ABSTRACT FROM AUTHOR]

Previous research largely concentrated on predicting load‐carrying capacities of concrete‐filled steel tubes (CFST) confined with fiber‐reinforced polymer (FRP) wraps under pure concentric loads, neglecting the more complex failure mechanisms that occur under real‐life eccentric loading conditions. This study, therefore, employs both finite element modeling (FEM) and machine learning methods to accurately predict the load‐bearing capacities under both concentric and eccentric loading conditions. This research analyzed a comprehensive dataset comprising 128 experimental tests and an equivalent number of FEM simulations designed to evaluate their eccentric performance. These models have been thoroughly generated and validated against existing literature. Additionally, the developed ML models, particularly a hybrid deep learning model, demonstrated significant predictive accuracy, with an average R2 value of 0.969 across all model folds. Partial dependence analysis further highlighted the significant influence of concrete strength and the interactive effects of steel tube area and FRP wrap thickness on the load‐carrying capacity of the columns. Furthermore, to enhance cost‐efficiency and resource management compared with traditional laboratory testing, a user‐friendly graphical user interface (GUI) has been developed and hosted on an open‐source platform such as GitHub. This interface supports real‐time, precise predictive capabilities and promotes a collaborative environment for ongoing model refinement and improvement. [ABSTRACT FROM AUTHOR]

There is an inverse relationship between the ability to generate force during concentric muscle movements and the velocity of contraction. However, this relationship is not the same in eccentric muscle movements due to differences in mechanism. Therefore, the study aimed to investigate the effects of higher isokinetic angular velocity on concentric and eccentric strength in the hamstring and quadriceps muscles. Twenty-four students from the faculty of sports science, aged between 18 and 24, participated in the study voluntarily. The participants completed a 5-minute standard warm-up, followed by concentric and eccentric knee extension (quadriceps) and knee flexion (hamstring) movements in the dominant leg at slower (60°/s) and faster (180°/s) angular velocities on the Cybex device (Cybex NORM®, Humac, CA, USA, 2004). The isokinetic strength outputs at slower and faster angular velocities were compared a one-way repeated-measures analysis of variance. When comparing the forces involved in concentric knee extension and flexion at slower and faster angular velocities, it was found that the force decreased significantly at higher speeds both during extension and flexion (p < 0.001). However, there was no significant changes in eccentric knee extension and flexion force outputs between slower and faster angular velocities (p > 0.05). Eccentric force outputs were significantly higher than concentric force in both angular velocities (p < 0.001). These results show that there is an inverse relationship between the velocity of concentric contractions and strength outputs, but not in eccentric contractions. It emphasizes the importance of healthcare professionals considering suitable exercise methods for athletes, especially when it comes to improving muscle strength or aiding in rehabilitation processes.

Abstract 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.

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 semiprofessional 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Although explosive upper-limb movements are far less studied than the equivalent lower-limb movements, they are important in many sports activities. The goal of this study was to explore, for the first time, the performance of street workout (SW) athletes who primarily focus on explosive and isometric strength in the upper limbs and to examine the effect of the contraction type on performance during a classical upper-body movement. Eighteen men took part in this study (age: 22.6 ± 2.1 years, height: 179.6 ± 7.1 cm, bodyweight: 71.9 ± 6.6 kg). Of these, nine practiced SW and nine practiced various team and individual sports—the latter serving as the control group. The athletes performed three different types of push-ups—one in a concentric way and two others in a plyometric way—and a fatigue-inducing push-up set. Jump heights, myoelectrical activities (through electromyography), muscle architecture, and hypertrophy (through ultrasonography) were measured. The results show no significant differences in jump height between the push-up types. Both groups confounded, but the SW athletes jumped on average 66 ± 21% higher than the control athletes (p < 0.05). There was no major difference in EMG between groups, regardless of the push-up type, but the SW athletes had a greater pectoralis major and anterior deltoid thickness as well as a greater pennation angle of the pectoralis major. The results suggest that the plyometric performance of the upper limbs does not follow the same pattern as that of the lower limbs. The SW group's greater capacity in performing explosive push-ups could be attributed to greater upper-body muscle hypertrophy and more efficient execution of the movement. [ABSTRACT FROM AUTHOR]

Considering the importance of body composition and lower-body strength and power for basketball players' on-court performance, as well as a lack of sports science research focused on female athletes, the purpose of the present investigation was to record the anthropometric and countermovement vertical jump (CMJ) characteristics of top-tier U16 and U18 female basketball players and examine between-group differences in the aforementioned tests. Thirty-two athletes who were a part of the national basketball academy volunteered to participate in the present investigation. Following the body composition assessment conducted via a segmental multifrequency bioimpedance analyzer, athletes performed three CMJs while standing on a force plate system sampling at 1000 Hz. Independent t-test and Mann-Whitney U-test were used to examine between-group differences. The findings reveal significant differences in body composition and lower-body neuromuscular performance characteristics between female basketball players ages 16 and 18. Although no differences were observed in muscle and body fat percentages, the U18 group had significantly greater height, overall body mass (both muscle and fat mass), as well as greater segmental fat-free mass (trunk, both legs and arms), intracellular and extracellular water, and body mass index when compared to their U16 counterparts. On the other hand, the U18 group demonstrated longer eccentric, concentric, and braking phase duration, as well as overall contraction time when compared to the U16 players. In addition, the U18 athletes exhibited higher eccentric mean force and power, concentric impulse, peak power, and mean and peak force. [ABSTRACT FROM AUTHOR]

As technology within elite basketball advances and is more available to sporting organizations, novel approaches for assessing and addressing athletic performance during practice or competition are being continuously explored. The aim of this investigation was to examine changes in neuromuscular performance during live basketball play. Eight professional male basketball players volunteered to participate in this study. The testing procedures were conducted during a pre-tournament camp over a span of 2 days. During the first day, the athletes were familiarized with the testing procedures, and baseline measurements were obtained. Using a uniaxial force plate system sampling at 1,000 Hz, each athlete performed 3 countermovement vertical jumps (CVJ) without an arm swing before proceeding with their regular training activities. During the second day of the pre-tournament camp, the athletes repeated identical CVJ testing procedures before the start of the first quarter and post-first, second, third, and fourth quarter of a simulated 5- on-5 basketball game. Repeated-measures testing design was used to examine statistically significant differences in various forcetime metrics of interest in comparison to the baseline levels (p, 0.05). Besides a trivial decrease in eccentric mean force, the findings of this study revealed no statistically significant changes in any force-time metrics of interest within both eccentric and concentric phases of the CVJ (i.e., mean and peak force and power, jump height, impulse, velocity, and contraction time). Thus, we can conclude that these variables were not sensitive to acute fatigue, suggesting that the neuromuscular performances of professional male basketball players tend to remain unchanged throughout a 5-on-5 simulated game. [ABSTRACT FROM AUTHOR]

With innovative force plate technology being available to many sports organizations worldwide that allow for time-efficient in-depth neuromuscular performance assessment, the purpose of the present study was to examine the relationship between some of the most commonly analyzed countermovement vertical jump (CVJ) force-time metrics and basketball playing time and efficiency. Twenty-four professional male basketball players volunteered to participate in the present study. The CVJ testing procedures were conducted within the first quarter of the competitive season span. Following a standardized warm-up protocol, each athlete stepped on a dual uni-axial force plate system sampling at 1,000 Hz and performed three maximum-effort CVJs with no arm swing. To minimize the possible influence of fatigue, each jump trial was separated by a 10–15 s rest interval and the average value across three jumps was used for performance analysis purposes. Basketball playing efficiency and average playing time were obtained at the end of the regular season competitive period from the coaching staff records and the official team records. Pearson product-moment correlation coefficients (r) were used to examine the strength of the relationships between force-time metrics and basketball playing time and efficiency, separately for each dependent variable (p < 0.05). A significant positive association was observed between playing efficiency and eccentric mean force and eccentric mean and peak power (r = 0.406–0.552). Similarly, an increase in eccentric mean power was positively correlated with the number of minutes played during the competitive season (r = 0.464). Moreover, the aforementioned relationship remained present even when eccentric mean power was expressed relative to the player’s body mass (r = 0.406). Thus, the findings of the present study indicate that, at the professional level of men’s basketball competition, CVJ eccentric strength and power have a positive impact on both playing time and efficiency. [ABSTRACT FROM AUTHOR]

Objectives: To show the superiority of eccentric versus concentric strengthening in terms of improving quadriceps strength in knee osteoarthritis (OA), a randomized controlled study was conducted to perform 12 sessions of either eccentric or concentric isokinetic muscle strengthening over 6 weeks. Methods: We recruited males and females, aged between 40 and 70 years, with predominantly unilateral femorotibial OA. Exclusion criteria were having a prosthesis, inflammatory arthritis or flare-up of OA, symptomatic patellofemoral OA, cardiovascular or pulmonary disease that could be a contraindication to the study treatment, and any pathology that could cause muscle weakness. The primary endpoint was the between-group difference in change in maximum concentric isokinetic knee extension peak torque (PT) at 60°/s on the OA side at 6 weeks. Secondary endpoints were between-group difference in change in concentric hamstring PT at 60°/s; eccentric quadriceps and hamstring PT at 30°/s; 10 m and 200 m walking speeds; pain and functional status (WOMAC score) at 6 weeks and 6 months. Results: The sample consisted of 11 females and 27 males, with a mean age of 57.7 ± 7.52 years and a body mass index (BMI) of 25.95 ± 3.93 kg/m2. Quadriceps strength increased more at 6 weeks in the concentric than the eccentric group with no statistical difference. There was a rate of 25% major adverse events in the eccentric group. Conclusions: Eccentric training resulted in a smaller improvement in quadriceps strength than concentric training and was associated with a high risk of muscle injury, particularly to the hamstring muscles. [ABSTRACT FROM AUTHOR]

With innovative portable force plate systems being widely implemented for lower-body neuromuscular performance assessment in an applied sports setting and the existing gap in the scientific literature regarding player performance during in-game competitive scenarios, the purpose of the present study was to compare changes in countermovement vertical jump (CVJ) performance pre-post a simulated 3×3 basketball tournament. Seven current or former members of a 3×3 national basketball team volunteered to participate in the present investigation. Upon completing standardized warm-up procedures, athletes stepped on a uni-axial force plate system sampling at 1,000 Hz and performed three maximal-effort CVJs with no arm swing. Then, the athletes proceeded to play a simulated 3×3 basketball tournament composed of two consecutive games, separated by a 15-min rest interval. Immediately following the completion of the second game, the identical CVJ testing procedures were repeated. Paired sample t-tests were used to examine pre-post-tournament differences in nineteen CVJ performance metrics (p < 0.05). The results reveal that force-time metrics during both eccentric and concentric phases of the CVJ remain relatively unchanged pre-post simulated 3×3 basketball tournament. However, multiple force-time metrics within the eccentric phase of the CVJ changed by 12.1%–19.1% (e.g., eccentric peak power and peak velocity, eccentric duration), suggesting that the eccentric phase of CVJ might be responsive to performance stimulus to a greater extent than the concentric phase. Overall, these findings further support the importance of comprehensive CVJ analysis when intending to measure changes in neuromuscular performance.

Given its fast-growing popularity and unique on-court competitive demands, 3 × 3 basketball has captured a considerable amount of attention over recent years. However, unlike research focused on studying 5 × 5 basketball players, there is a lack of scientific literature focused on examining countermovement vertical jump (CMJ) and sprint performance characteristics of 3 × 3 athletes. Thus, the purpose of the present study was to compare force-time metrics during both eccentric and concentric phases of the CMJ and acceleration and deceleration capabilities between 3 × 3 and 5 × 5 top-tier professional male basketball athletes. Ten 3 × 3 and eleven 5 × 5 professional basketball players volunteered to participate in the present study. Upon completion of a standardized warm-up, each athlete performed three maximum-effort CMJs, followed by two 10 m sprints. A uni-axial force plate system sampling at 1,000 Hz was used to analyze CMJ force-time metrics and a radar gun sampling at 47 Hz was used to derive sprint acceleration-deceleration measures. Independent t-tests and Hedge's g were used to examine between-group statistically significant differences (p<0.05) and effect size magnitudes. The findings of the present study reveal that 3 × 3 and 5 × 5 professional male basketball players tend to display similar neuromuscular performance characteristics as no significant differences were observed in any force-time metric during both eccentric and concentric phases of the CMJ (g=0.061-0.468). Yet, prominent differences were found in multiple measures of sprint performance, with large effect size magnitudes (g = 1.221-1.881). Specifically, 5 × 5 basketball players displayed greater average and maximal deceleration and faster time-to-stop than their 3 × 3 counterparts. Overall, these findings provide reference values that sports practitioners can use when assessing athletes' CMJ and sprint performance capabilities as well as when developing sport-specific training regimens to mimic on-court competitive demands. [ABSTRACT FROM AUTHOR]

With innovative force plate technology being available to many sports organizations worldwide that allow for time-efficient in-depth neuromuscular performance assessment, the purpose of the present study was to examine the relationship between some of the most commonly analyzed countermovement vertical jump (CVJ) force-time metrics and basketball playing time and efficiency. Twenty-four professional male basketball players volunteered to participate in the present study. The CVJ testing procedures were conducted within the first quarter of the competitive season span. Following a standardized warm-up protocol, each athlete stepped on a dual uni-axial force plate system sampling at 1,000 Hz and performed three maximum-effort CVJs with no arm swing. To minimize the possible influence of fatigue, each jump trial was separated by a 10–15 s rest interval and the average value across three jumps was used for performance analysis purposes. Basketball playing efficiency and average playing time were obtained at the end of the regular season competitive period from the coaching staff records and the official team records. Pearson product-moment correlation coefficients (r) were used to examine the strength of the relationships between force-time metrics and basketball playing time and efficiency, separately for each dependent variable (p

BACKGROUND: Resistance exercises are widely used to enhance muscle hypertrophy. Hypertrophy occurs with effect of mechanical loading, metabolic stress, and muscle damage. The time under tension in eccentric, isometric, and concentric phases of resistance exercises can alter muscle damage and anabolic hormone responses. OBJECTIVES: The aim of the study was to reveal the effect of the time spent in the concentric and eccentric phases of the movement on muscle damage and anabolic hormone response during resistance exercise. METHODS: Ten male subjects participated in the study. A, B, C tempo protocols were created by changing the time under tension to be 1 or 2 seconds in the eccentric and concentric phases of bench press and squat movements. In all protocols, isometric phases were 0 sec. The metronome was used to apply tempos. Blood samples were taken before each protocol, after administration, and in the 24 th , 48 th and 72 nd hours after exercise; and serum insulin, testosterone, Insuline-like Growth Factor-1 (IGF-1), Creatine Kinase (CK) and Lactate Dehydrogenase (LDH) levels were evaluated. RESULTS: Time-wise changes in CK were statistically different for all protocols (p < 0.05). CK levels in the 24 th hour of the protocol C and the 48 th hour of the protocol B were significantly higher than those in the other protocols (p < 0.05). IGF-1 and testosterone levels were significantly higher in the protocol B in the post-test, compared to the other protocols (p < 0.05). Insulin levels in the 24 t ⁢ h hour were significantly higher in the protocol B compared to those in others (p < 0.05). Time-wise changes in LDH parameters were not statistically significant in any hours (p > 0.05). CONCLUSIONS: Extending time under tension in the eccentric phase of a bout of resistance exercise appears to affect the anabolic hormone response and muscle damage. In this way, increased metabolic response and mechanical stress can induce muscle mass gain. [ABSTRACT FROM AUTHOR]

Given its fast-growing popularity and unique on-court competitive demands, 3 × 3 basketball has captured a considerable amount of attention over recent years. However, unlike research focused on studying 5 × 5 basketball players, there is a lack of scientific literature focused on examining countermovement vertical jump (CMJ) and sprint performance characteristics of 3 × 3 athletes. Thus, the purpose of the present study was to compare force-time metrics during both eccentric and concentric phases of the CMJ and acceleration and deceleration capabilities between 3 × 3 and 5 × 5 top-tier professional male basketball athletes. Ten 3 × 3 and eleven 5 × 5 professional basketball players volunteered to participate in the present study. Upon completion of a standardized warm-up, each athlete performed three maximum-effort CMJs, followed by two 10 m sprints. A uni-axial force plate system sampling at 1,000 Hz was used to analyze CMJ force-time metrics and a radar gun sampling at 47 Hz was used to derive sprint acceleration-deceleration measures. Independent t-tests and Hedge's g were used to examine between-group statistically significant differences (p

Context: Strength deficits of the hamstrings following sports injuries decrease athletic performance and increase the risk of injury recurrence. Previous studies have shown a high correlation between the muscular strength during hip-extension and knee-flexion and total muscle size of the hamstrings. However, it remains unclear which region of the individual hamstring muscles is closely associated with muscular strength. Objective: To investigate the relationship between the size of each region of the individual hamstring muscles and muscular strength during hip extension and knee flexion. Design: Within-subject repeated measures. Setting: University laboratory. Participants: Twenty healthy young male volunteers who regularly engaged in sports activities. Outcome Measures: Anatomical cross-sectional areas were acquired from the proximal, middle, and distal regions of the biceps femoris long head, biceps femoris short head, semitendinosus, and semimembranosus. Hip-extension and knee-flexion strength were measured during maximal voluntary isometric and concentric contractions (angular velocities of 60°/s and 180°/s). Results: The anatomical cross-sectional area of the distal regions in biceps femoris long head (r =.525–.642) and semitendinosus (r =.567) were significantly correlated with hip-extension strength under all conditions and only at an angular velocity of 180°/s, respectively. Meanwhile, anatomical cross-sectional areas of the distal regions in biceps femoris short head (r =.587–.684) and semimembranosus (r =.569–.576) were closely associated with knee-flexion strength under all conditions. Conclusion: These results suggest that muscle size in the distal regions of biceps femoris long head and semitendinosus greatly contributes to the production of hip-extension strength, whereas that of biceps femoris short head and semimembranosus significantly contributes to the generation of knee-flexion strength. These findings could be useful for designing training and rehabilitation programs to efficiently improve strength deficits following sports injuries such as strain injury and anterior cruciate ligament tears. [ABSTRACT FROM AUTHOR]

Although explosive upper-limb movements are far less studied than the equivalent lower-limb movements, they are important in many sports activities. The goal of this study was to explore, for the first time, the performance of street workout (SW) athletes who primarily focus on explosive and isometric strength in the upper limbs and to examine the effect of the contraction type on performance during a classical upper-body movement. Eighteen men took part in this study (age: 22.6 ± 2.1 years, height: 179.6 ± 7.1 cm, bodyweight: 71.9 ± 6.6 kg). Of these, nine practiced SW and nine practiced various team and individual sports—the latter serving as the control group. The athletes performed three different types of push-ups—one in a concentric way and two others in a plyometric way—and a fatigue-inducing push-up set. Jump heights, myoelectrical activities (through electromyography), muscle architecture, and hypertrophy (through ultrasonography) were measured. The results show no significant differences in jump height between the push-up types. Both groups confounded, but the SW athletes jumped on average 66 ± 21% higher than the control athletes (p < 0.05). There was no major difference in EMG between groups, regardless of the push-up type, but the SW athletes had a greater pectoralis major and anterior deltoid thickness as well as a greater pennation angle of the pectoralis major. The results suggest that the plyometric performance of the upper limbs does not follow the same pattern as that of the lower limbs. The SW group’s greater capacity in performing explosive push-ups could be attributed to greater upper-body muscle hypertrophy and more efficient execution of the movement.

Abstract Background This study examined the relationships between impulse and kinetic variables during jumping and landing in elite young male volleyball players. Methodology Eighteen players were recruited and asked to jump on a force plate, which allowed for the direct extraction of jump and landing kinetic data. The data was then analysed using stepwise regression to explore the relationship between landing impulse and various kinetic variables. Results Our findings revealed a significant positive relationship between the peak rate of force development concentric (PRFD CON) and impulse at landing (β = 0.537, p = 0.02). In a secondary analysis, we found that PRFD CON (β = 0.497, p = 0.01) and time to peak power concentric (TPPC) (β = 0.424, p = 0.04) were also positively correlated with landing impulse. Importantly, PRFD CON and TPPC were the variables that had the most muscular predictive power for impulse at landing. Conclusion These findings offer crucial insights into the biomechanics of jumping and landing in elite young male volleyball players, informing the development of more effective training programs. Our study identifies PRFD CON and TPPC as critical factors for improving landing impulse, emphasizing the need to consider multiple kinetic variables when designing training programs for explosive skills. These insights can help optimize performance and reduce the risk of injury in elite young male volleyball players.

Glass fibers reinforced polymer (GFRP) were used to longitudinally and transversally 12 columns and while the other 4 columns were reinforced with steel or steel and GFRP as reference specimens. This research dealt with several parameters under different loading conditions, such as the reinforcing material and spacing between ties. This study aims to find out the ability of the reinforced columns with GFRP to bear the loads. In addition, investigate the mode of failure in these columns and their appropriateness in the structures since the columns are compression members. The tested results revealed that the concentric loading columns give higher resistance than their eccentrically loaded counterparts. Also, the hybrid column (steel and GFRP) had the highest peak load compared with the fully reinforced steel and GFRP columns. In addition, the fully GFRP RC- column had an ultimate load slightly less than its steel counterpart under the same loading condition.

With force plates being widely implemented for neuromuscular performance assessment in sport-specific settings and various force-time metrics being able to differentiate athletes based on their performance capabilities, the purpose of the present study was to examine the differences in countermovement vertical jump (CVJ) characteristics between starting and non-starting professional male basketball players (e.g., ABA League). Twenty-three athletes (height = 199.2 ± 7.7 kg, body mass = 94.2 ± 8.2 kg, age = 23.8 ± 4.9 years) volunteered to participate in the present investigation. Upon completion of a standardized warm-up protocol, each athlete performed three maximal-effort CVJs without an arm swing while standing on a uni-axial force plate system sampling at 1,000 Hz. Independent t-tests were used to examine statistically significant differences (p

Cardiac hypertrophy develops following different triggers of pressure or volume overload. In several previous studies, different hypertrophy types were demonstrated following alterations in extracellular signal-regulated kinase (ERK) pathway activation. In the current study, we studied two types of cardiac hypertrophy models in rats: eccentric and concentric hypertrophy. For the eccentric hypertrophy model, iron deficiency anemia caused by a low-iron diet was implemented, while surgical aortic constriction was used to induce aortic stenosis (AS) and concentric cardiac hypertrophy. The hearts were evaluated using echocardiography, histological sections, and scanning electron microscopy. The expression of ERK1/2 was analyzed using Western blot. During the study period, anemic rats developed eccentric hypertrophy characterized by an enlarged left ventricle (LV) cavity cross-sectional area (CSA) (59.9 ± 5.1 mm2 vs. 47 ± 8.1 mm2, p = 0.002), thinner septum (2.1 ± 0.3 mm vs. 2.5 ± 0.2 mm, p < 0.05), and reduced left ventricular ejection fraction (LVEF) (52.6% + 4.7 vs. 60.3% + 2.8, p < 0.05). Rats with AS developed concentric hypertrophy with a thicker septum (2.8 ± 0.6 vs. 2.4 ± 0.1 p < 0.05), increased LV muscle cross-sectional area (79.5 ± 9.33 mm2 vs. 57.9 ± 5.0 mm2, p < 0.001), and increased LVEF (70.3% + 2.8 vs. 60.0% + 2.1, p < 0.05). ERK1/2 expression decreased in the anemic rats and increased in the rats with AS. Nevertheless, the p-ERK and the p-MEK did not change significantly in all the examined models. We concluded that ERK1/2 expression was altered by the type of hypertrophy and the change in LVEF. [ABSTRACT FROM AUTHOR]

An experimental study has been done into the effects of vertical mechanical vibrating, vertical eccentricity, and the Rayleigh number on natural convection heat transferring out of a horizontally enclosed, ending cylindrical annulus with a radius rate of 2.6 and an aspect ratio of (2:1). The annulus produced between two concentric and vertically eccentric circular cylinders is positioned horizontally, and its internal wall is uniformly heated while isothermally cooling the external wall. The range of present conditions for Rayleigh number is 5×〖10〗^4≤Ra≤6.48×〖10〗^6 , and Pr= 0.703, the frequency of vibration is 0f 20Hz; and the amplitude is b mm), with possible exclusion of the highest positive and negative eccentricities. Plots of the average Nusselt number variation against the Rayleigh number showed a significant increase in negative vertical eccentricity. It was found that the average Nusselt decreased as the internal cylinder changed its location vertically from negative to positive through the center, which is normally a desirable effect, but has no advantage over the concentric on the positive side. However, an increase in the Rayleigh number leads to a nearly proportional increase in the average Nusselt number and a smaller yet still substantial increase in positive eccentricity.

Background: This study examined the relationships between impulse and kinetic variables during jumping and landing in elite young male volleyball players. Methodology: Eighteen players were recruited and asked to jump on a force plate, which allowed for the direct extraction of jump and landing kinetic data. The data was then analysed using stepwise regression to explore the relationship between landing impulse and various kinetic variables. Results: Our findings revealed a significant positive relationship between the peak rate of force development concentric (PRFD CON) and impulse at landing (β = 0.537, p = 0.02). In a secondary analysis, we found that PRFD CON (β = 0.497, p = 0.01) and time to peak power concentric (TPPC) (β = 0.424, p = 0.04) were also positively correlated with landing impulse. Importantly, PRFD CON and TPPC were the variables that had the most muscular predictive power for impulse at landing. Conclusion: These findings offer crucial insights into the biomechanics of jumping and landing in elite young male volleyball players, informing the development of more effective training programs. Our study identifies PRFD CON and TPPC as critical factors for improving landing impulse, emphasizing the need to consider multiple kinetic variables when designing training programs for explosive skills. These insights can help optimize performance and reduce the risk of injury in elite young male volleyball players. [ABSTRACT FROM AUTHOR]

Hamstring strain injuries are prevalent in many sports. Research has demonstrated that the Nordic hamstring exercise (NHE), a knee-dominant exercise addressing the posterior chain muscles, can aid in reducing the risk of hamstring injuries in athletes. However, most research on hamstring injury prevention has focused on performing the eccentric version of the NHE (NHEECC). In contrast, in sports, it is quite frequent for athletes to use an eccentric–concentric version of the NHE. Additionally, eccentric NHE is typically performed using a slow, controlled tempo. The effect of a fast stretch-shortening cycle NHE (NHESSC) compared to standard slow NHEECC on peak knee flexor force has not been investigated. The aim of the study was therefore to investigate fast NHESSC vs. standard slow NHEECC. Our hypothesis posited that peak knee flexor force would be greater for fast NHESSC compared with standard slow NHEECC. The study involved 22 elite athletes (actively competing in both national and international events) consisting of female (n = 10) and male (n = 7) track and field athletes and male football players (n = 5), aged 17–31 years. The participants performed maximum trials of slow NHEECC and fast NHESSC repetitions in which measurement of bilateral peak knee flexor force was conducted at the ankle with the use of a load cell. During the NHEs, a linear encoder was used to measure both the position where the peak knee flexor force was recorded and the average eccentric velocity. SSC contributed to an enhanced NHE performance, where bilateral absolute peak knee flexor force was 13% higher for fast NHESSC vs. standard slow NHEECC (822 vs. 726 N, p < 0.01, ES = 0.54). Participants achieved a 32% greater forward distance at the breakpoint stage during NHEECC compared to the coupling phase for NHESSC (54 vs. 41 cm, p < 0.001, ES = 1.37). Eccentric average velocity was more than three times higher for NHESSC compared with NHEECC (0.38 vs. 0.12 m/s, p < 0.001, ES = 3.25). The key findings of this study were that SSC contributed to an enhanced NHE performance, where absolute peak knee flexor force was 13% greater for fast NHESSC compared to standard slow NHEECC. The fast NHESSC could therefore be an interesting alternative to the standard slow NHEECC execution, as it may offer potential advantages for sprint performance, as well as hamstring injury prevention and rehabilitation. [ABSTRACT FROM AUTHOR]

Hamstring tightness is a feeling that is often felt by futsal players, which can interfere with performance during playing. Previous studies suggest that stretching can solve it. However, feeling hamstring tightness is associated with weakness, so strengthening exercises are required to treat it. Strengthening exercises consist of concentric and eccentric exercises, which differ in the direction of muscle contraction. This study aimed to observe the effect of concentric, eccentric, and stretching exercises on muscle length, endurance, and power following hamstring tightness. 49 futsal players who experienced hamstring tightness participated in this study. Participants were divided into three groups consisting of Nordic Hamstring Exercise (NHE), Leg Curl Exercise (LCE), and control group (CTRL) - which only did stretching exercises. The exercises were carried out for 6 weeks, three times per week. The sit and reach test, Passive Knee extension test, Single leg bridge test, and Leg dynamometer tests were used to determine the changes in hamstring muscle before and after the exercises. One-way ANOVA was performed to compare changes between groups. All participants were found to be in the good category (28.78±5.53 cm) in sit and reach test and had low performance (39.13±16.77) in the leg dynamometer test before the intervention series. However, sit and reach test was shown not to be significantly different between groups (p>0.05) as well as ROM. Single-leg bridging test and leg dynamometer significantly differed between groups (p<0.05). This study suggests that feeling tight in the hamstring muscle is not correlated with muscle length. Concentric exercise increased strength more than eccentric and stretching. While concentric exercise increased the endurance of the hamstring muscle. [ABSTRACT FROM AUTHOR]

Connected adaptive resistance exercise (CARE) machines are new technology purported to adjust resistance exercise loads in response to muscle fatigue. The present study examined muscle fatigue (strength loss, fatigue perceptions) during maximal eccentric‐only (ECCmax‐only), concentric‐only (CONmax‐only), and coupled ECC‐CON (ECCmax‐CONmax) bicep curl exercise on a CARE machine. Eleven men and nine women completed the three protocols in separate sessions and in random order. All protocols included 4 sets of 20 maximal effort muscle contractions. Strength loss was calculated as Set 4 set end load minus Set 1 highest load. The CARE machine's algorithm adjusted resistances automatically, permitting continued maximal effort repetitions without stopping. Consequently, all protocols caused substantial fatigue. Women were most susceptible to strength loss from exercise that included maximal efforts in the ECC phase, whereas men were most susceptible to strength loss from exercise that included maximal efforts in the CON phase. With ECCmax‐only exercise, ECC strength loss (mean ± SD) was similar between men (55.9 ± 14.1%) and women (56.4 ± 10.8%). However, with CONmax‐only exercise, men and women experienced 55.6 ± 6.2% and 35.3 ± 8.7% CON strength loss, respectively. With ECCmax‐CONmax exercise, men experienced greater ECC (62.9 ± 7.7%) and CON (77.0 ± 5.3%) strength loss than women (ECC: 48.5 ± 15.7%, CON: 66.2 ± 12.1%). Heightened perceptions of fatigue and pain of the exercised limb were reported after all protocols. Women generally reported more biceps pain than men. The results illustrate CARE technology delivers ECC‐only and accentuated ECC exercise feasibly. Acute responses to repeated maximal effort bicep curl exercise with such technology might differ between men and women depending on muscle contraction type. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine whether the modulation of primary afferent depolarization (PAD) and homosynaptic post-activation depression (HPAD) are involved in the lower efficacy of Ia-afferent-α-motoneuron transmission commonly observed during lengthening compared to isometric and shortening conditions. Methods: 15 healthy young individuals participated in two experimental sessions dedicated to measurement in passive and active muscle states, respectively. In each session, PAD, HPAD and the efficacy of Ia-afferent-α-motoneuron transmission were evaluated during lengthening, shortening and isometric conditions. PAD was evaluated with D1 inhibition technique. Posterior tibial nerve stimulation was used to study HPAD and the efficacy of the Ia-afferent-α-motoneuron transmission through the recording of the soleus Hoffmann reflex (H reflex). Results: PAD was increased in lengthening than shortening (11.2%) and isometric (12.3%) conditions regardless of muscle state (P < 0.001). HPAD was increased in lengthening than shortening (5.1%) and isometric (4.2%) conditions in the passive muscle state (P < 0.05), while no difference was observed in the active muscle state. H reflex was lower in lengthening than shortening (− 13.2%) and isometric (− 9.4%) conditions in both muscle states (P < 0.001). Conclusion: These results highlight the specific regulation of PAD and HPAD during lengthening conditions. However, the differences observed during passive lengthening compared to shortening and isometric conditions seem to result from an increase in Ia-afferent discharge, while the variations highlighted during active lengthening might come from polysynaptic descending pathways involving supraspinal centres that could regulate PAD mechanism. [ABSTRACT FROM AUTHOR]

Purpose: To report the detection rate of colorectal tumors with computed tomography (CT) performed within 1 year before diagnosis for indications other than colon abnormalities. Strategies to improve cancer detection are reported. Methods: Two board-certified, subspecialty-trained abdominal radiologists retrospectively reviewed patient health records and CT images with knowledge of tumor location/size. Patients were classified into 3 groups: prospective (colon abnormality suggesting neoplasm documented in radiologic report), retrospective (not documented in radiologic report but detected in our retrospective review of CT images), and undetected (neither prospectively nor retrospectively detected). Retrospective detection confidence and morphologic characteristics of each tumor were also recorded. Results: Of 209 included patients, 106 (50.7%) had prospectively detected tumors, 66 (31.6%) had retrospectively detected tumors, and 37 (17.7%) had undetected tumors. Asymmetric bowel wall thickening and polypoid masses were present more often in the retrospective group than in the prospective group (27% vs. 10.5% and 26% vs. 17.1%, respectively). Tumors in the ascending colon were more likely to be detected retrospectively than prospectively (odds ratio, 2.75; 95% CI 1.07–7.08; P = 0.04). Undetected tumors were smaller on average (2.9 cm) than prospective (6.0 cm) and retrospective (4.9 cm) tumors (P = 0.03). Detection confidence was lower for retrospectively detected tumors than for prospectively detected tumors (P = 0.03). Indications other than abdominal pain were most common for retrospectively detected tumors (P = 0.03). Use of intravenous contrast material was lowest in the undetected group (P = 0.003). The prospective group had more pericolonic abnormalities, regional/retroperitoneal lymph node involvement (P < 0.001), and distant metastases than did the retrospective group (P = 0.01). Conclusion: Half of all colorectal tumors were not detected prospectively. Radiologists should perform meticulous colon tracking regardless of the indication for CT. The right colon merits additional examination. Polypoid and asymmetric morphologic characteristics were most often overlooked, but these characteristics can be learned to improve detection. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was 1) to determine and compare kinetic parameters during the realization of a countermovement jump (CMJ) between footballers with cerebral palsy (CP) and non-impaired footballers, and 2) to analyze the differences in this action between different players’ impairment profiles and a group of non-impaired footballers. Methods: This study involved 154 participants comprising 121male footballers with CP from 11 national teams and 33 male non-impaired football players recruited as the control group (CG). The footballers with CP were described according to the different impairment profiles (bilateral spasticity = 10; athetosis or ataxia = 16; unilateral spasticity = 77; minimum impairment = 18). All participants performed three CMJs on a force platform to record kinetic parameters during the test. Results: The group of para-footballers presented significantly lower values than the CG in the jump height (p < 0.01, d = −1.28), peak power (p < 0.01, d = −0.84), and the net concentric impulse (p < 0.01, d = −0.86). Concerning the pairwise comparisons between CP profiles and the CG, significant differences were found for the bilateral spasticity, athetosis or ataxia, and unilateral spasticity subgroups compared to the non-impaired players for jump height (p < 0.01; d = −1.31 to −2.61), power output (p < 0.05; d = −0.77 to −1.66), and concentric impulse of the CMJ (p < 0.01; d = −0.86 to −1.97). When comparing the minimum impairment subgroup with the CG, only significant differences were found for jump height (p = 0.036; d = −0.82). Footballers with minimum impairment presented higher jumping height (p = 0.002; d = −1.32) and concentric impulse (p = 0.029; d = −1.08) compared to those with bilateral spasticity. Also, the unilateral spasticity subgroup reports a higher jump height performance than the bilateral group (p = 0.012; d = −1.12). Conclusion: These results suggest that the variables related to power production during the concentric phase of the jump are crucial for the performance differences between groups with and without impairment. This study provides a more comprehensive understanding of kinetic variables that would differentiate CP and non-impaired footballers. However, more studies are necessary to clarify which parameters better differentiate among different profiles of CP. The findings could help to prescribe effective physical training programs and support the classifier’s decision-making for class allocation in this para-sport. [ABSTRACT FROM AUTHOR]

An experimental study has been done into the effects of vertical mechanical vibrating, vertical eccentricity, and the Rayleigh number on natural convection heat transferring out of a horizontally enclosed, ending cylindrical annulus with a radius rate of 2.6 and an aspect ratio of (2:1). The annulus produced between two concentric and vertically eccentric circular cylinders is positioned horizontally, and its internal wall is uniformly heated while isothermally cooling the external wall. The range of present conditions for Rayleigh number is 5×10^4 = Ra= 6.48×10^6, and Pr = 0.703, the frequency of vibration is 0 = f = 20Hz; and the amplitude is b mm), with possible exclusion of the highest positive and negative eccentricities. Plots of the average Nusselt number variation against the Rayleigh number showed a significant increase in negative vertical eccentricity. It was found that the average Nusselt decreased as the internal cylinder changed its location vertically from negative to positive through the center, which is normally a desirable effect, but has no advantage over the concentric on the positive side. The Rayleigh number was found to be relatively sensitive to eccentricity. However, an increase of Rayleigh number leads to a nearly proportional increase in the average Nusselt number and a smaller yet still substantial increase in positive eccentricity. This study concluded that the vibration under the current experimental setup significantly affects the concentric position of the internal cylinder, whether the effect is positive or negative. The vibrational average Nusselt number increased in varying proportions, depending on the location of the heated inner cylinder. [ABSTRACT FROM AUTHOR]

We report the microfabrication and characterization of concentric gold nanoring electrodes (Au NREs), which were fabricated by patterning two gold nanoelectrodes on the same silicon (Si) micropillar tip. Au NREs of 165 ± 10 nm in width were micropatterned on a 6.5 ± 0.2 µm diameter 80 ± 0.5 µm height Si micropillar with an intervening ~ 100 nm thick hafnium oxide insulating layer between the two nanoelectrodes. Excellent cylindricality of the micropillar with vertical sidewalls as well as a completely intact layer of a concentric Au NRE including the entire micropillar perimeter has been achieved as observed via scanning electron microscopy and energy dispersive spectroscopy data. The electrochemical behavior of the Au NREs was characterized by steady-state cyclic voltammetry and electrochemical impedance spectroscopy. The applicability of Au NREs to electrochemical sensing was demonstrated by redox cycling with the ferro/ferricyanide redox couple. The redox cycling amplified the currents by 1.63-fold with a collection efficiency of > 90% on a single collection cycle. The proposed micro-nanofabrication approach with further optimization studies shows great promise for the creation and expansion of concentric 3D NRE arrays with controllable width and nanometer spacing for electroanalytical research and applications such as single-cell analysis and advanced biological and neurochemical sensing. [ABSTRACT FROM AUTHOR]

In the current study, the investigation of heat transfer and fluid flow Characteristics of Pure water when pass through a double tube heat exchanger (DTHX). this investigation has been conducted across various Reynolds Number to gain insights into their performance also conducted a computational fluid dynamics (CFD) simulation using the ANSYS-FLUENT 22 R1 software. Result obtained was validated by comparing to empirical correlation data found in the existing literature. The investigation considered various operating variable as Reynolds Number and temperature across the inner, and outer tubes. Specifically, the Reynolds Number of a range of 2500 to 5500 at 333 K, and 2500 at 303 K for the respective tubes. Key findings are that friction factor is increase by 6.38% as compared to correlation (Blasius) in existing literature. And Nusselt number (Nu) increase by 40.84% as compared to correlation at the Reynolds Number (Re) of 2500. The heat transfer coefficients (hi) were increased by 8.30% as compared to existing literature.

In the current study, the investigation of heat transfer and fluid flow Characteristics of Pure water when pass through a double tube heat exchanger (DTHX). This investigation has been conducted across various Reynolds Number to gain insights into their performance also conducted a computational fluid dynamics (CFD) simulation using the ANSYS-FLUENT 22 R1 software. The study employed mathematical models and thermophysical properties of nanofluids and water, which were sourced from existing literature. The analysis focused on comparing pure water, 1% Al2O3/H2O nanofluids. The investigation considered various operating variable as Reynolds Number and temperature across the inner, and outer tubes. Specifically, the Reynolds Number of a range of 2500 to 5500 at 80°C, and 2500 at 15°C for the respective tubes. Key findings are that friction factor for pure water, 1% alumina nf, 2% alumina nf, and 3% alumina nf is increased by 4.61%,11.42%,15.06% and 16.21% as compared to Gnielinski correlation in existing literature at a Reynolds Number of 2500 and this increase in friction factor is 5.66%, 13.79%, 18.03% and 19.61% respectively at Reynolds number of 5500. Nusselt number (Nu) for pure water, 1% alumina nf, 2% alumina nf, and 3% alumina nf is increased by 24.92%, 50.04%, 59.90% and 64.31% as compared to Gnielinski correlation in existing literature at a Reynolds Number of 2500 and this increase is 10.84%, 28.68%, 35.31% and 41.55% respectively at Reynolds number of 5500. The heat transfer coefficients (hi) for pure water, 1% alumina nf, 2% alumina nf, and 3% alumina nf is increased by 3.17%, 7.29%, 8.49% and 8.94% as compared to Gnielinski correlation in existing literature at a Reynolds Number of 2500 and this increase is 8.04%, 18.49%, 21.54% and 22.64% respectively at Reynolds number of 5500.

This study investigates the heat transfer and fluid flow characteristics of pure water passing through a double tube heat exchanger (DTHX). Computational fluid dynamics (CFD) simulations were conducted using ANSYS-FLUENT 22 R1 software. Mathematical models and thermophysical properties of nanofluids and water from existing literature were employed. The comparison focused on pure water and 1% Al2O3/H2O nanofluids. Various operating variables such as Reynolds number and temperature were considered across the inner and outer tubes. The Reynolds number ranged from 2500 to 5500 at 80°C for the inner tube and 2500 at 15°C for the outer tube. Key findings include a 7.69% increase in friction factor for 1% Al2O3/H2O compared to pure water and a 16% increase compared to the Gnielinski correlation at a Reynolds number of 2500. The Nusselt number (Nu) exhibited a 98.42% increase compared to the Gnielinski correlation at a Reynolds number of 5500 and a 39% increase compared to pure water at the same Reynolds number. Heat transfer coefficients (hi) were found to increase by 9.52% compared to pure water and 12% compared to the correlation in existing literature.

In the current study, the investigation of heat transfer and fluid flow Characteristics of Pure water when pass through a triple tube heat exchanger (CTTHX). this investigation has been conducted across various Reynolds Number to gain insights into their performance also conducted a computational fluid dynamics (CFD) simulation using the ANSYS-FLUENT software. Result obtained was validated by comparing to empirical correlation data found in the existing literature. The investigation considered various operating variable as Reynolds Number and temperature across the inner, intermediate, and outer tubes. Specifically, the Reynolds Number of 2000 at 305 K, a range of 2000 to 4500 at 340 K, and 2000 at 295 K for the respective tubes. Key findings are that friction factor increase by 12.5% as compared to correlation in existing literature. And Nusselt number (Nu) increase by 50% in the range of Reynolds Number (Re) from 2000 to 4500.

In the current study, the investigation of heat transfer and fluid flow Characteristics of Pure water when pass through an inner annulus triangular shape and circular shape triple tube heat exchanger (CTTHX). this investigation has been conducted across various Reynolds Number to gain insights into their performance also conducted a computational fluid dynamics (CFD) simulation using the ANSYS-FLUENT software. Result obtained was validated by comparing to empirical correlation data found in the existing literature. The investigation considered various operating variable as Reynolds Number and temperature across the inner, intermediate, and outer tubes. Specifically, the Reynolds Number of 2000 at 305 K, a range of 2000 to 4500 at 340 K, and 2000 at 295 K for the respective tubes. Key findings are that friction factor of triangular shape is increase by 10.5% and for circular shape by 2.69% as compared to correlation in existing literature. And Nusselt number (Nu) for triangular shape increase by 39.19% and for circular shape by 13.30% as compared to correlation in the range of Reynolds Number (Re) from 2000 to 4500. The effectiveness was increased by 16.67% and 7.6% for triangular shape and circular shape respectively as compared to existing literature.

Background and Study Aim. The aim of this study is to investigate the effects of different types of contractions on muscle damage and muscle fatigue in sedentary individuals. Material and Methods. Thirty healthy male sedentary individuals participated in the study. Strength training in different types of contractions applied in the study was applied 3 times a week for 8 weeks. Before the study, the training loads were determined by making maximal force measurements of all subjects. The 30 subjects participating in the study were divided into 3 groups: isometric (n = 10), concentric (n = 10) and eccentric (n = 10) contraction group. Appropriate amount of blood samples was taken from the elbow vein 2 times from all subjects, before the studies and at the end of the 8-week strength training. Results. It was observed that eight-week strength training did not cause muscle fatigue in all groups and did not create a statistically significant difference (P> 0.05). Strength training with isometric and concentric contractions for eight weeks significantly increased serum lactate dehydrogenase (LDH), C-reactive protein (CRP), myoglobin (Mb), interleukin 6 (IL-6) levels, while concentric strength training significantly reduced serum aspartate amino transferase (AST) levels. Strength training with eccentric contractions significantly increased serum LDH, CRP, AST, Mb and IL-6 levels, while significantly reducing serum tumor necrosis factor alpha (TNF-α) levels. Strength training with eccentric contractions significantly increased serum creatine kinase (CK), CRP, AST, IL-6 and Mb levels compared to strength training with isometric and concentric contractions at the end of the eight-week study period, but did not show the same significant effect in other parameters. Conclusions. As a result, it can be said that eccentric strength training performed in sedentary individuals leads to more muscle damage than isometric and concentric strength training.

Objectives: The purpose of this study was 1) to determine and compare kinetic parameters during the realization of a countermovement jump (CMJ) between footballers with cerebral palsy (CP) and non-impaired footballers, and 2) to analyze the differences in this action between different players’ impairment profiles and a group of non-impaired footballers.Methods: This study involved 154 participants comprising 121 male footballers with CP from 11 national teams and 33 male non-impaired football players recruited as the control group (CG). The footballers with CP were described according to the different impairment profiles (bilateral spasticity = 10; athetosis or ataxia = 16; unilateral spasticity = 77; minimum impairment = 18). All participants performed three CMJs on a force platform to record kinetic parameters during the test.Results: The group of para-footballers presented significantly lower values than the CG in the jump height (p < 0.01, d = −1.28), peak power (p < 0.01, d = −0.84), and the net concentric impulse (p < 0.01, d = −0.86). Concerning the pairwise comparisons between CP profiles and the CG, significant differences were found for the bilateral spasticity, athetosis or ataxia, and unilateral spasticity subgroups compared to the non-impaired players for jump height (p < 0.01; d = −1.31 to −2.61), power output (p < 0.05; d = −0.77 to −1.66), and concentric impulse of the CMJ (p < 0.01; d = −0.86 to −1.97). When comparing the minimum impairment subgroup with the CG, only significant differences were found for jump height (p = 0.036; d = −0.82). Footballers with minimum impairment presented higher jumping height (p = 0.002; d = −1.32) and concentric impulse (p = 0.029; d = −1.08) compared to those with bilateral spasticity. Also, the unilateral spasticity subgroup reports a higher jump height performance than the bilateral group (p = 0.012; d = −1.12).Conclusion: These results suggest that the variables related to power production during the concentric phase of the jump are crucial for the performance differences between groups with and without impairment. This study provides a more comprehensive understanding of kinetic variables that would differentiate CP and non-impaired footballers. However, more studies are necessary to clarify which parameters better differentiate among different profiles of CP. The findings could help to prescribe effective physical training programs and support the classifier’s decision-making for class allocation in this para-sport.

Neuromuscular efficiency is defined as the ratio of work output to stimulation rate. The purpose of these experiments was to test the hypothesis that neuromuscular efficiency would be increased in proportion to posttetanic potentiation, that is, the stimulation‐induced increase in work output displayed by rodent fast‐twitch muscle. To this end, extensor digitorum longus muscles from wild‐type and skeletal myosin light chain kinase knockout (skMLCK−/−) mice were surgically isolated and suspended in vitro (25°C). Concentric force development during shortening at 70% of maximal unloaded shortening velocity was tested at stimulus frequencies between 10 and 80 Hz both before and after a potentiating tetanus. A strong genotype‐dependent difference in the potentiation of concentric work output was observed; concentric work output of wild‐type muscles was increased by 51%–88% while that of skMLCK−/− muscles was increased by only 20%–34% across the frequencies tested. As a result, comparison of work – frequency plots revealed that the frequency required for peak and 50% peak unpotentiated work of wild‐type muscles was decreased from ~80 to 52 Hz and from ~48 to 21 Hz, respectively. By contrast, the frequency required for peak and 50% peak unpotentiated work of skMLCK−/− muscles was decreased from ~80 to 68 Hz and from ~51 to 41 Hz, respectively. Thus, wild‐type muscles with the ability to phosphorylate myosin displayed larger increases in neuromuscular efficiency than skMLCK−/− muscles (25–30 vs 10–15 Hz, respectively). This suggests that the presence of myosin phosphorylation may ameliorate or mitigate fatigue mechanisms associated with high‐frequency stimulation rates. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effects of eccentric-concentric exercises applied at different resistances on strength parameters. Thirty-five sedentary volunteers participating in the study were divided into 4 groups by the stratified randomization method according to their mean strength parameters. These groups were named as control group (CG) (age 21.00 ± 2.44 years, height 178.13 ± 6.83 cm, body weight 80.13 ± 12.14 kg), eccentric group (EG) (age 22.22 ± 2.99 year, height 178.22 ± 5.95 cm, body weight 71.22 ± 9.36 kg), con-eccentric group (CEG) (age 21.22 ± 2.86 year, height 177.22 ± 4.68 cm, body weight 71.89 ± 13.93 kg) and modified con-eccentric group (MCEG) (age 21.67 ± 2.59 year, height 177.00 ± 4.30 cm, body weight 75.22 ± 8.16 kg). During the 8-week training period, 4 sets of leg extension exercises with different loads were applied to the training groups 3 days a week. Isokinetic strength outputs were measured both concentrically and eccentrically at 60°s-1 ve 180°s-1 angular velocities with the Cybex device. SPSS 24 package program was used in the statistical analysis of the data. For normally distributed data, paired sample t-test was used in paired comparisons, and a one-way ANOVA test was used for comparison between three or more groups. Tukey and Dunnett's T3 (non-homogeneous) test was used among the post hoc tests. Wilcoxon test (paired comparisons) and Kruskal-Wallis test were used for nonparametric data. When the intragroup comparisons were examined before and after the training period, it was found that the isokinetic strength outputs of EG, CEG, and MCEG showed a significant increase in all contractions and angular velocities (p lt;0.05), but no parameters increased in CG (p gt;0.05). When the isokinetic pre-test strength parameters between the groups were compared, no significant difference was found (p gt;0.05). While only MCEG increased significantly in 180°s-1 concentric strength outputs, 60°s-1 and 180°s-1 eccentric strength output increased significantly in both MCEG and EG compared to CG (p lt;0.05). As a result, when the strength tests are considered, although the general strength development is seen mostly in MKEG, no statistically significant difference was found between training groups. It is recommended to determine the load in the eccentric phases of the exercises by the eccentric 1RM (repetition maximum), at least as a result of this research, to generate more strength development rates while applying strength training.

An experimental investigation has been carried out to find the effect of subcooling of moderator temperature under a Pressure Tube (PT) concentric with Calandria Tube (CT) (e = 0) and PT contact with CT (e = 8.5 mm) at a quasi-steady temperature of a center pin at 750 ℃. The circumferential temperature distribution at different axial positions has been established for the PT and CT. The results demonstrated that a large circumferential temperature gradient was observed in the pressure tube during contact conditions. The maximum and minimum temperatures were measured at the top and bottom nodes of the pressure tube. However, the CT exhibited an opposite trend. The maximum temperature difference between the top and bottom surfaces of the PT and CT is 148 °C and 9.1 °C, respectively. However, no substantial temperature variations were observed between the PT and the CT in concentric conditions. [ABSTRACT FROM AUTHOR]

Abstract Neuromuscular efficiency is defined as the ratio of work output to stimulation rate. The purpose of these experiments was to test the hypothesis that neuromuscular efficiency would be increased in proportion to posttetanic potentiation, that is, the stimulation‐induced increase in work output displayed by rodent fast‐twitch muscle. To this end, extensor digitorum longus muscles from wild‐type and skeletal myosin light chain kinase knockout (skMLCK−/−) mice were surgically isolated and suspended in vitro (25°C). Concentric force development during shortening at 70% of maximal unloaded shortening velocity was tested at stimulus frequencies between 10 and 80 Hz both before and after a potentiating tetanus. A strong genotype‐dependent difference in the potentiation of concentric work output was observed; concentric work output of wild‐type muscles was increased by 51%–88% while that of skMLCK−/− muscles was increased by only 20%–34% across the frequencies tested. As a result, comparison of work – frequency plots revealed that the frequency required for peak and 50% peak unpotentiated work of wild‐type muscles was decreased from ~80 to 52 Hz and from ~48 to 21 Hz, respectively. By contrast, the frequency required for peak and 50% peak unpotentiated work of skMLCK−/− muscles was decreased from ~80 to 68 Hz and from ~51 to 41 Hz, respectively. Thus, wild‐type muscles with the ability to phosphorylate myosin displayed larger increases in neuromuscular efficiency than skMLCK−/− muscles (25–30 vs 10–15 Hz, respectively). This suggests that the presence of myosin phosphorylation may ameliorate or mitigate fatigue mechanisms associated with high‐frequency stimulation rates.