Hasil untuk "cond-mat.supr-con"

Keiji Koyama, Shuhei Hosono

ABSTRACT Koyama, K and Hosono, S. Comparison of the effects of barefoot and shod training on foot structure, muscle strength, and sensory function. J Strength Cond Res XX(X): 000-000, 2026-The aim of this study was to compare the effects of 8 weeks multicomponent lower-limb training under barefoot versus shod conditions on foot muscle strength, structure, and sensory function. Healthy adults were assigned to either a barefoot training (BARE; n = 11), shod training (SHOD; n = 11), or control (CON; n = 15) groups. BARE and SHOD completed 2 weekly training including agility, balance, and strength exercises. Measurements were taken at baseline and weeks 2, 4, 6, and 8. Outcome measures included toe flexor strength, foot arch height, and foot sensory threshold. Relative toe flexor strength increased at weeks 4, 6, and 8 in both BARE and SHOD compared with baseline and was higher than in CON. For standing relative toe flexor strength, BARE showed greater values at weeks 6 and 8 than at weeks 2, and the value at week 6 was greater than at week 4, whereas in SHOD, only values at week 8 were greater than values at week 2. In contrast, arch-related variables and foot sensory threshold showed no significant changes during most of the training period in either group, and between-group differences were generally not significant. In CON, no significant changes were observed in nearly all outcome measures from baseline to week 8. Throughout the training period, no significant differences were found between BARE and SHOD in nearly all outcome measures. Overall, compared with shod training, 8 weeks of barefoot multicomponent exercises led to continued improvement in standing toe flexor strength without changing foot structure and sensory function.

Felipe Lisboa, Felipe Gomes, Gabriel Kunevaliki et al.

ABSTRACT Lisboa, F, Gomes, F, Kunevalik, G, Manske, I, Santos, V, Prado, A, Cavalcanti, A, Tricoli, I, Costa, B, Kassiano, W, Stavinski, N, Francsuel, J, and Cyrino, ES. Ankle position-dependent muscle swelling during seated leg curl: ultrasonographic insights into the hamstrings and medial and lateral gastrocnemius. J Strength Cond Res XX(X): 000-000, 2026-The seated leg curl is one of the most prescribed exercises in hamstring strength training. Although it is a monoarticular exercise, changing the position of the ankle may influence the engagement of the muscles involved during the exercise (i.e., hamstrings and gastrocnemius muscles). We compared the lateral gastrocnemius (LG), medial gastrocnemius, and hamstrings (HT) during the seated leg curl exercise with the ankle in a neutral ankle position (NAP), plantar flexion position (PFP), and a control condition (CON), in which subjects did not perform any exercise and instead remained at rest for a duration equivalent to the exercise sessions. Each condition was performed on a different day, once per week. Muscle swelling was measured immediately after exercise and at the corresponding time point in the control condition. Seventeen young women (18-37 years) performed the experimental protocols and control condition in a crossover and counterbalanced design. In the experimental conditions, subjects performed a specific warm-up with 50% of the initial load for the exercise, completing 12 repetitions, followed by 3 sets to concentric failure, with a 2-minute interval between sets in the following conditions: NAP and PFP. The primary outcome showed that NAP resulted in greater swelling in LG compared with the CON (mean difference = 0.05 cm; 95% CI: 0.004-0.11; ES = 0.6) and with PFP (mean difference = 0.07 cm; 95% CI: 0.009-0.14; ES = 0.6). For HT, swelling was greater in NAP compared with CON (mean difference = 0.18 cm; 95% CI: 0.08-0.2; ES = 1.1) and in PFP compared with CON (mean difference = 0.14 cm; 95% CI: 0.02-0.2; ES = 0.9), but no significant difference was found between NAP and PFP (mean difference = 0.03 cm; 95% CI: -0.16 to 0.24; ES = 0.2). Our findings suggest that in the NAP condition, there is muscle swelling in both the LG and HT, whereas in the PFP condition, muscle swelling is observed only in the HT.

Alysson Enes, A. Piñero, Thomas Hermann et al.

Enes, A, Piñero, A, Hermann, T, Zamanzadeh, A, Hennessy, T, Montenegro, D, Parnell, C, Jia, A, Weitzman, T, Wolf, M, Korakakis, PA, Swinton, PA, and Schoenfeld, BJ. How slow should you go? A systematic review with meta-analysis of the effect of resistance training repetition tempo on muscle hypertrophy. J Strength Cond Res 39(12): 1331–1339, 2025—We systematically searched the literature for interventions that compared different resistance training tempos for eccentric (ECC) or concentric (CON) actions. We estimated pre-/poststudy changes and between-condition differences in lean/muscle mass for healthy adults, restricting inclusion to studies that controlled all other training variables. Hierarchical meta-analyses were conducted within a Bayesian framework, with change estimates made within groups, and the primary emphasis placed on pairwise differences between dichotomously coded slower (repetition time: 1.7–4.5 seconds, averaging ∼3.5 seconds) and faster (repetition time: 0.3–2 seconds, averaging ∼1 second) interventions. When combining data across all 14 included studies (4 CON and 9 ECC manipulated interventions, 1 for both in a cross-over design), meta-analyses of within-group changes showed similar pooled effects for faster (0.43 [95% CrI: 0.29‒0.58]) and slower tempos (0.34 [95% credible interval (CrI): 0.22‒0.47)]. Meta-analyses of pairwise differences across the same studies showed central estimates that trivially favored faster over slower tempos (pooled mean = 0.09 [95% CrI: −0.04 to 0.22]), with a low probability that the between-condition effect size was at least small ( p = 0.450), medium ( p = 0.001), or large ( p < 0.001). Subgroup analyses of pairwise differences stratified by muscle action type (ECC or CON), body region (upper or lower body), and training to failure (yes or no) generally produced trivial to small effects, although the certainty of estimates varied across analyses. In conclusion, resistance training tempo appears to have minimal overall effect on muscle hypertrophy, with potential differences emerging under specific conditions.

Vaibhavi Rathod, Cheongeun Oh, Wen K. Ling et al.

ABSTRACT Rathod, V, Oh, C, Ling, W, and Rao, S. Proximal and distal impairments in runners with Achilles tendinopathy compared with matched controls. J Strength Cond Res XX(X): 000-000, 2025-This study investigated drop countermovement jump (DCMJ) performance in runners with midportion Achilles tendinopathy (AT). Recreational runners with midportion AT (n = 23) were compared with age- and sex-matched control (CON) runners (n = 23). Subjects performed a minimum of 3 trials of single leg DCMJ that involved jumping off a 20 cm box. Pain during and after jump performance was assessed using a Numeric Pain Rating Scale. Victorian Institute of Sport Assessment- AT and Tampa scale of Kinesiophobia were recorded. Three-dimensional motion analysis was used to assess jump height and lower extremity joint kinematics. Paired t-tests (p < 0.05) and regression analyses were conducted to examine between-group differences and the role of group membership (AT/CON) age, body mass index, and weekly running mileage on dependent variables. Runners with AT demonstrated impaired single-leg DCMJ performance, particularly in ankle kinematics during the propulsion phase. Jump height and ankle plantarflexion during the propulsion phase were significant predictors of group membership (AT/CON). In addition, clinically relevant subgroups with reduced hip extension torque were identified. Drop countermovement jump proved to be a robust assessment tool for evaluating AT in high-impact sports subjects. Notably, all subjects were highly functioning recreational runners with no ankle strength deficits or symptoms during the jump; however, moderate-to-large performance deficits were found in the AT group. Clinicians may incorporate DCMJ assessments to monitor progress and guide rehabilitation in individuals with AT.

L. S. L. da Silva, L. S. Gonçalves, Pedro Henrique Alves Campos et al.

Supplemental Digital Content is Available in the Text. Abstract da Silva, LSL, Gonçalves, LdS, Alves Campos, PH, Benjamim, CJR, Tasinafo Júnior, MF, de Lima, LCR, Bueno Júnior, CR, and Alves, CPdL. Comparison between eccentric vs. concentric muscle actions on hypertrophy: a systematic review and meta-analysis. J Strength Cond Res 39(1): 115–134, 2025—Different physiological mechanisms of sarcomere activity during eccentric (ECC) and concentric (CON) muscle actions led to investigations into muscle hypertrophy outcomes, but conclusions remain elusive. We aimed to investigate the effects of ECC vs. CON muscle actions on muscle hypertrophy in apparently healthy adults through a systematic review with meta-analysis. The searches were conducted on EMBASE, MEDLINE, Cochrane Library, Web of Science, Scopus, and SPORTDiscus databases. To be eligible for inclusion, studies had to: (a) be randomized/controlled trials; (b) investigate the effects of CON vs. ECC resistance training programs in apparently healthy adults; (c) assess hypertrophy outcomes using direct imaging for cross-sectional area, muscle thickness, or muscle volume. A total of 15,778 studies were identified, and 26 (682 subjects included in the meta-analysis) met the inclusion criteria. The main findings indicated no statistical difference between ECC vs. CON on hypertrophy measurements (0.285 [95% CI: −0.131 to 0.701]; p = 0.179; I2: 84.4%; GRADE: very low). Subgroup meta-analysis analyzing possible hypertrophy outcome moderators as age (18–59 years old and ≥60 years old) and weeks of intervention duration (>8 weeks) did not reveal differences between ECC vs. CON. Subgroup analysis revealed an effect favoring the ECC for the upper limb muscles (p = 0.018), ≤8 weeks of intervention (p = 0.046), muscle thickness assessment (p = 0.0352), and isokinetic contraction (p = 0.0251). Our findings suggest similar hypertrophy between ECC and CON muscle actions in apparently healthy adults. However, it appears that the muscles of the upper limbs, shorter interventions, hypertrophy assessment method, and the contraction type may favor ECC muscle actions.

Paulo Augusto Arteaga Uribe

Las condicionales del español con la estructura cond + imperfecto de subjuntivo + condicional simple de indicativo evidencian la aparición de la flexión condicional en la prótasis, contrario a lo establecido en el español estándar. Además, de acuerdo con Lavandera (1984) y De Granda (1998), la diferencia entre grado de realidad podría motivar la aparición de dicha flexión de condicional en prótasis. Así, se busca vincular el grado de realidad con la aparición de la flexión de condicional simple de indicativo en la prótasis. A partir de lo propuesto por Thompson, Longacre y Hwang (2007) sobre grados de realidad, la Gramática de Construcciones (Hoffman y Trousdale, 2013), así como las investigaciones de Lavandera (1984) y De Granda (1998), se pone a prueba esa variable con cuestionarios escritos1.

Irma García Oliveros, Nerea Meabe Iturbe, J. M. Marín Ojea et al.

Introducción y Objetivos: Evaluar el impacto del entrenamiento intensivo de marcha con el exoesqueleto pediátrico ATLAS 2030 en la función motora gruesa, así como determinar el mantenimiento de los efectos post-intervención en niños con parálisis cerebral (PC). Sujetos y Métodos: Estudio prospectivo controlado no aleatorizado. Participaron 13 niños con PC. Se implementó un programa de 4 sesiones semanales de 65 minutos durante 6 semanas. Se evaluó la función motora gruesa con la Gross Motor Function Measure de 88 ítems (GMFM-88), la resistencia física al ejercicio con el test de los seis minutos marcha (6MWT) con el dispositivo y se registró el número de pasos caminado en cada sesión en cada modo de uso para evaluar la adaptación a la actividad. Se realizaron 3 evaluaciones, antes del tratamiento, al finalizarlo (6 semanas) y una última evaluación de seguimiento a las 12 semanas. Resultados: La puntuación total de la GMFM-88 mostró cambios significativos al finalizar la intervención (p < 0,001), persistiendo en el seguimiento (p < 0,001). El número de pasos en automático y en activo aumentaron significativamente tras la intervención (p < 0,001), manteniéndose en el seguimiento (p = 0,001). Por último, el 6MWT aumentó de manera significativa tras la intervención, reduciéndose en el seguimiento (p < 0,001). Conclusiones: El entrenamiento intensivo de 6 semanas con ATLAS 2030 impacta positivamente en la función motora gruesa de niños con PC, aumentando los beneficios 6 semanas después de la finalización del tratamiento. La resistencia física y la adaptación a la actividad mejoran con el uso continuado. Estos resultados respaldan el potencial del ATLAS 2030 como estrategia terapéutica intensiva en esta población. Registro de Ensayos Clínicos: No: NCT07066956. https://clinicaltrials.gov/search?cond=NCT07066956.

Claudia Kearney, Edward K. Coughlan, Aidan O’Connell et al.

Abstract Kearney, C, Coughlan, EK, O'Connell, A, Lacey, S, and Burns, C. Bigger but are they better? Investigating growth, maturation, and physical performance metrics in underage Gaelic games development squads. J Strength Cond Res 39(6): e806–e814, 2025—The purpose of this study was to examine (a) maturation status distribution across intercounty underage Gaelic games development squads and (b) differences in physical performance metrics relative to maturation status. The study is the first to assess physical performance metrics in intercounty development squad Gaelic Games players, with reference to maturation status. The Khamis & Roche method was used to establish maturation status in 254 male U15 and U16 Gaelic Games development squad players. Tests for lower body power (countermovement jump [CMJ] height), linear speed (10, 20 m), upper body strength (maximum chin-up test), and aerobic endurance (GAA modified Bronco) were conducted. One-way multivariate analysis of variance and analysis of variance were conducted, with an alpha level of p 0.05), while U16 ED and OT displayed faster 20 m speed than LD (p = 0.023, p = 0.024, respectively). Coach education around growth and maturation and strategies such as biobanding should be used in talent development settings. Practitioners should interpret speed times relative to maturation status as opposed to chronological age.

Conor J. Cantwell, Zachary S. Schroeder, Lauren K. Marshall-Ciochon et al.

ABSTRACT Cantwell, CJ, Schroeder, ZS, Marshall-Ciochon, LK, Campbell, BA, Taber, CB, and Suchomel, TJ. Force production and barbell velocity characteristics across multiple sets of different accentuated eccentric loading conditions. J Strength Cond Res XX(X): 000-000, 2025-The purpose of this study was to examine the impact that multiple accentuated eccentric loaded (AEL) back squat sets have on force production and barbell velocity characteristics within 2 different loading conditions. Sixteen resistance-trained men performed 3 sets of 3 back squat repetitions while using 100% of their 1 repetition maximum (1RM) during the eccentric phase of the first repetition and either 60% (100-60) or 80% (100-80) 1RM on the concentric phase of the first repetition and the eccentric-concentric phases of the subsequent 2 repetitions. Braking and propulsion net mean force, duration, and net impulse as well as mean and peak barbell velocity were compared between loading schemes and sets using a series of 2-way repeated measures ANOVA. Significantly greater propulsion net mean force and mean barbell velocity were produced during the 100-60 condition than during the 100-80 condition across all sets (p < 0.001). In addition, significantly greater (p < 0.001) set-averaged braking net mean force and net impulse and peak barbell velocity were produced during the 100-60 condition while greater braking and propulsion duration (p < 0.001) and net impulse (p = 0.031) were produced during the 100-80 condition. Within each loading condition, trivial-small differences existed across sets for all variables (g ≤ 0.39). Multiple sets of AEL back squats can be prescribed using 100-60 and 100-80 loading schemes without negatively affecting force or velocity characteristics. Strength and conditioning practitioners may prescribe 100-60 to enhance rapid force production characteristics and 100-80 to provide a strength stimulus to enhance force development.

N. Kumar, Jon L. Oliver, Jason S. Pedley et al.

Francisco J. Barrera-Domínguez, S. Talpey, B. J. Almagro et al.

ABSTRACT Barrera-Domínguez, FJ, Scott Talpey, Almagro, BJ, and Molina-López, J. Effect of individualized training based on change of direction deficit on speed performance in basketball players. J Strength Cond Res XX(X): 000-000, 2025-Linear and changes of direction (COD) speed are considered key performance determinants in basketball. The aim of this study was to analyze the effect of an individualized COD deficit-based training program on linear speed and COD efficiency, and performance in basketball players. In addition, the differences in linear speed and COD performance between 2 time periods (4 and 8 weeks) with this training were analyzed. Thirty-six male basketball players (age, 21.4 ± 3.23 years; height, 1.87 ± 0.07 m; body mass, 83.6 ± 7.83 kg) were divided into an intervention group (INT, n = 18), who performed an individualized COD deficit-based training, and a control group (CON, n = 18), who underwent a nonindividualized multidirectional repeated sprint training program. Both groups performed the intervention 2 days per week. Baseline, 4-week, and 8-week assessments included 10 meters linear speed and COD (5 + 5 meters at 45°, 90°, and 180° cut) tests. An improvement in multidirectional speed efficiency was observed from 4 weeks in the INT group (effect size [ES] ≥ 1.61, p < 0.01), with no change in the CON group. After 8 weeks, significant improvements were observed in the INT players' mean speed performance (mean difference [MD] -0.09, ES = 0.34, p < 0.01), with COD180° showing the greatest changes (MD ≤ -0.18, ES ≥ 0.44, p < 0.01). In conclusion, an individualized COD deficit-based training program improved speed performance after 8 weeks, with changes in multidirectional speed efficiency after first 4 weeks. Given basketball's unpredictable and multidirectional nature, strength and conditioning coaches should seek the optimal trade-off between the linear and multidirectional speed demands on their players.

M. Swift, J. L. Lyons

In this comment on"Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite"(arXiv:2307.16892 [cond-mat.supr-con]), we discuss the flat half-occupied two-band manifold that appears in $\mathrm{Pb}_9\mathrm{Cu}(\mathrm{PO}_4)_6(\mathrm{OH})_2$ when using a semilocal DFT functional. We argue that the flat band is an artifact of the functional's overestimation of the energy of the oxygen p states in the valence band. When using the HSE hybrid functional, the energy of the oxygen p states is reduced, and the copper-derived manifold splits into one fully occupied and one empty band. While these results do not rule out the possibility of superconductivity in doped LK-99, they do predict that stoichiometric $\mathrm{Pb}_9\mathrm{Cu}(\mathrm{PO}_4)_6(\mathrm{OH})_2$ is an insulator, not a superconductor. Furthermore, we have shown that future first-principles studies of these materials should employ hybrid functionals or other advanced methods to ensure that the oxygen-derived valence-band energies are correctly described.

J. A. Flores-Livas, A. Sanna, E. Gross

Due to its low atomic mass, hydrogen is the most promising element to search for high-temperature phononic superconductors. However, metallic phases of hydrogen are only expected at extreme pressures (400 GPa or higher). The measurement of the record superconducting critical temperature of 203 K in a hydrogen-sulfur compound at 160 GPa of pressure [A.P. Drozdov, M.I. Eremets, I.A. Troyan, arXiv:1412.0460 [cond-mat.supr-con] (2014); A.P. Drozdov, M.I. Eremets, I.A. Troyan, V. Ksenofontov, S.I. Shylin, Nature 525, 73 (2015)], shows that metallization of hydrogen can be reached at significantly lower pressure by inserting it in the matrix of other elements. In this work we investigate the phase diagram and the superconducting properties of the H-S systems by means of minima hopping method for structure prediction and density functional theory for superconductors. We also show that Se-H has a similar phase diagram as its sulfur counterpart as well as high superconducting critical temperature. We predict H3Se to exceed 120 K superconductivity at 100 GPa. We show that both H3Se and H3S, due to the critical temperature and peculiar electronic structure, present rather unusual superconducting properties.

S. Salk

Daichi Manabe, Hiroyasu Koizumi

We present a possible explanation for a recently observed magnetic field induced charge order in cuprate superconductors (Edkins et al.~arXiv:1802.04673 [cond-mat.supr-con]). We argue that it arises from the reorganization of spin-vortex-induced loop current (SVILC) pattern due to supercurrent-flow caused by the magnetic field. The reorganization is from the most stable tiling of $4a times 6a$ spin-vortex quartets ($a$ is the lattice constant in the CuO$_2$ plane, and a spin-vortex quartet is stable of unit of spin-vortices that contains four holes, four spin-vortices, and four SVILCs) to that of $4a times 8a$ spin-vortex quartets. The consequence of this reorganization will lead to the enhancement of $8a$ charge order, and reduction of $6a$ charge order. The former is observed in the experiment, but the latter is not confirmed, so far. However, it may be confirmed if the experimental result is carefully reexamined.

Daichi Manabe, H. Koizumi

We present a possible explanation for a recently observed magnetic field induced charge order in cuprate superconductors (Edkins et al. arXiv:1802.04673 [cond-mat.supr-con]). We argue that it arises from the reorganization of spin-vortex-induced loop current (SVILC) pattern due to supercurrent-flow caused by the magnetic field. The reorganization is from the most stable tiling of 4a 6a spin-vortex quartets (a is the lattice constant in the CuO2 plane, and a spin-vortex quartet is stable of unit of spin-vortices that contains four holes, four spin-vortices, and four SVILCs) to that of 4a 8a spin-vortex quartets. The consequence of this reorganization will lead to the enhancement of 8a charge order, and reduction of 6a charge order. The former is observed in the experiment, but the latter is not confirmed, so far. However, it may be confirmed if the experimental result is carefully reexamined.

J. Camargo-Martínez, D. Espitia, R. Baquero

Yu. M. Shukrinov, I. R. Rahmonov, M. A. Gaafar

The effect of electromagnetic wave irradiation on the phase dynamics of intrinsic Josephson junctions in high temperature superconductors is investigated. We predict three novel effects by variation of the radiation amplitude and frequency: changing of the longitudinal plasma wavelength at parametric resonance; double resonance of the Josephson oscillations with radiation and longitudinal plasma wave; charging of superconducting layers in the current interval corresponding to the Shapiro step. The "bump" structure in IVC recently observed experimentally is demonstrated. We also observe ragged Shapiro steps at double resonance.