bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of Bioelectrical Impedance Devices for the Determination of Body Fat Percentage in Firefighters
Authors: Jagim Andrew R. , Luedke Joel , Erickson Jacob L. , Fields Jennifer B. , Jones Margaret T. 
Published: July 2024

Abstract
Jagim, AR, Luedke, J, Erickson, JL, Fields, JB, and Jones, MT. Validation of bioelectrical impedance devices for the determination of body fat percentage in firefighters. J Strength Cond Res 38(8): e448–e453, 2024—To cross-validate bioelectrical impedance devices for the determination of body fat percentage (BF%) in firefighters. Twenty-eight structural firefighters were evaluated (female, n = 2; male, n = 26 [mean ± SD] age: 38.2 ± 8.3 years; height: 180.2 ± 7.5 cm; body mass: 86.7 ± 20.8 kg; body mass index: 25.8 ± 7.8 kg·m−2) using multifrequency bioelectrical impedance analysis (MFBIA) hand-to-foot device, and single-frequency BIA foot scale (F2FBIA), and a single-frequency handheld BIA device (HHBIA). Dual X-ray absorptiometry served as the criterion. Validity metrics were examined to establish each method's performance. Body fat % values produced by MFBIA (r = 0.913), F2FBIA (r = 0.695), and HHBIA (r = 0.876) were strongly associated (p < 0.001) with criterion BF% measures. However, MFBIA, F2FBIA, and HHBIA all significantly (p < 0.001) underestimated BF% when compared with the criterion measure. Constant error ranged between 4.0 and 5.5% across all BIA devices. Despite strong associations between the BIA devices included in the current study and the criterion measure, all BIA devices underestimated BF%, which resulted in an overestimation of fat-free mass. In addition, proportional bias was observed in which BF% was overestimated at lower values and underestimated at higher values.
How Do Young Soccer Players Train? A 5-Year Analysis of Weekly Training Load and its Variability Between Age Groups in an Elite Youth Academy
Authors: Connolly Darragh R. , Stolp Sean , Gualtieri Antonio , Ferrari Bravo Duccio , Sassi Roberto , Rampinini Ermanno , Coutts Aaron J. 
Published: July 2024

Abstract
Connolly, DR, Stolp, S, Gualtieri, A, Ferrari Bravo, D, Sassi, R, Rampinini, E, and Coutts, AJ. How do young soccer players train? A 5-year analysis of weekly training load and its variability between age groups in an elite youth academy. J Strength Cond Res 38(8): e423–e429, 2024—The aim of this study was to quantify the session rating of perceived exertion (sRPE), duration, and training load accrued across typical training weeks undertaken by youth soccer players. Differences between starters, nonstarters, and variations in training load variables were also investigated. Data were collected from 230 elite youth players in 4 age groups (U15, U16, U17, and U19) during 5 competitive seasons. Mixed models were used to describe variation between age groups and compare starters with nonstarters, with season as a fixed covariate effect. Week-to-week variation in training load was expressed as the percentage coefficient of variation. The main findings may be used to highlight a significant effect of age and playing status on training intensity, duration, and internal training load. Weekly training load increased progressively from the U15 to U17, with significant differences between each age group (p < 0.03). Lower mean weekly perceived intensity (sRPE) was noted in U15 when compared with the older age groups (4.2 vs. 4.6–4.9 arbitrary unit for U16 to U19, p < 0.001). Low weekly training load variation was observed across the different phases of the season in each age group, with the preseason exhibiting the greatest variance (3.6–6.2%). Differences in the training load are likely more attributable to changes in training duration rather than sRPE. Control of session duration seems to play an important role when aiming to control load in the academy environment, and practitioners should closely monitor the differences in duration and load being recorded between starters and nonstarters.
Efficacy of Supersets Versus Traditional Sets in Whole-Body Multiple-Joint Resistance Training: A Randomized Controlled Trial
Authors: Iversen Vegard Moe , Eide Vemund Bakken , Unhjem Bjørnar Jakobsen , Fimland Marius Steiro 
Published: July 2024

Abstract
Iversen, VM, Eide, VB, Unhjem, BJ, and Fimland, MS. Efficacy of supersets versus traditional sets in whole-body multiple-joint resistance training: A randomized controlled trial. J Strength Cond Res 38(8): 1372–1378, 2024—Time constraints often hinder exercise engagement, necessitating exploration of time-efficient resistance training methods. Superset training, where 2 exercises are performed successively with minimal rest, nearly halves session duration but is metabolically demanding, possibly reducing strength gains. In a randomized controlled trial with blinded test leaders, we examined the efficacy of supersets versus traditional sets in a full-body, multiple-joint resistance training workout on maximal strength in the trained exercises. Subjects took part in a 3-week introductory training phase before baseline testing to ensure they were thoroughly familiarized. Next, they were randomized to a superset- or a traditional-set group, performing 10 weeks of heavy multiple-joint resistance training twice per week. The exercise programs consisted of leg press, bench press, lat pull-down, and seated rows. The traditional training group had a 5.2-kg higher improvement in pull-down than the superset group (p = 0.033), and a close to significant 4.8-kg higher improvement in seated rows (p = 0.073). The improvements in leg press and bench press were quite similar for both groups (p = 0.507–0.527). There were no changes between groups in body composition outcomes (0.151–0.640), but both groups increased muscle mass and reduced fat mass (p < 0.05). In conclusion, superset training of multi-joint exercises hampered maximal strength gains somewhat compared with traditional-set training. However, there were very similar improvements in body composition, and strength gains were observed for all exercises in the superset group. Thus, whole-body, multiple-joint superset resistance training could be a viable time-saving approach.
The Expression of the Force-Length Properties of the Gastrocnemius in Ice Hockey Players
Authors: Leonard Cameron , Challis John H. 
Published: July 2024

Abstract
Leonard, C and Challis, JH. The expression of the force-length properties of the gastrocnemius in ice hockey players. J Strength Cond Res 38(9): 1635–1639, 2024—Although the force-length properties of muscles have an approximately parabolic shape, in vivo not all the force-length curve is necessarily used, only a portion of the curve is expressed (i.e., ascending, plateau, or descending regions of the force-length curve). The number of sarcomeres in series in a muscle fiber affects the expressed section of the force-length curve; this number can be influenced by the nature of activity the muscle experiences. It was hypothesized that the reduced range of motion ice skaters experience, because of the constraints imposed by the ice skates, that the gastrocnemii of a group of ice skaters will adapt and will more frequently express in vivo the plateau of the force-length curve compared with a nonspecifically trained population. Twelve NCAA Division I female ice hockey players volunteered for the study. Their maximum isometric ankle plantarflexion moments were recorded for 6 ankle angles and 3 knee angles. Exploiting the biarticularity of the gastrocnemius, the expressed sections of the subject's force-length curves were determined. Six subjects operated over the ascending limb, 5 operated over the plateau region, and 1 over the descending limb. This frequency of distribution for ice hockey players was statistically different to the distribution measured for 28 nonspecifically trained subjects from a previous study (p < 0.0001). These results likely reflect morphological differences between the 2 groups for their gastrocnemii, potentially arising from the limited range of gastrocnemius length feasible in ice-skates. These results have implications for the specificity of their off-ice training for ice hockey players.
The Use of Free Weight Squats in Sports: A Narrative Review—Squatting Movements, Adaptation, and Sports Performance: Physiological
Authors: Stone Michael H. , Hornsby Guy , Mizuguchi Satoshi , Sato Kimitake , Gahreman Daniel , Duca Marco , Carroll Kevin , Ramsey Michael W. , Stone Margaret E. , Haff G. Gregory 
Published: July 2024

Abstract
Stone, MH, Hornsby, G, Mizuguchi, S, Sato, K, Gahreman, D, Duca, M, Carroll, K, Ramsey, MW, Stone, ME, and Haff, GG. The use of free weight squats in sports: a narrative review—squatting movements, adaptation, and sports performance: physiological. J Strength Cond Res 38(8): 1494–1508, 2024—The squat and its variants can provide numerous benefits including positively affecting sports performance and injury prevention, injury severity reduction, and rehabilitation. The positive benefits of squat are likely the result of training-induced neural alterations and mechanical and morphological adaptations in tendons, skeletal muscles, and bones, resulting in increased tissue stiffness and cross-sectional area (CSA). Although direct evidence is lacking, structural adaptations can also be expected to occur in ligaments. These adaptations are thought to beneficially increase force transmission and mechanical resistance (e.g., resistance to mechanical strain) and reduce the likelihood and severity of injuries. Adaptations such as these, also likely play an important role in rehabilitation, particularly for injuries that require restricted use or immobilization of body parts and thus lead to a consequential reduction in the CSA and alterations in the mechanical properties of tendons, skeletal muscles, and ligaments. Both volume and particularly intensity (e.g., levels of loading used) of training seem to be important for the mechanical and morphological adaptations for at least skeletal muscles, tendons, and bones. Therefore, the training intensity and volume used for the squat and its variations should progressively become greater while adhering to the concept of periodization and recognized training principles.
Impact of Weekly Training-Load Structure and Content on the Risk of Injury in Professional Rugby Union Match-Play
Authors: Chéradame Jérémy , Loursac Romain , Piscione Julien , Carling Christopher , Decq Philippe , Jacqmin-Gadda Hélène 
Published: July 2024

Abstract
Chéradame, J, Loursac, R, Piscione, J, Carling, C, Decq, P, and Jacqmin-Gadda, H. Impact of weekly training-load structure and content on the risk of injury in professional Rugby Union match-play. J Strength Cond Res 38(9): 1613–1619, 2024—The aim of this study was to investigate the impact of different components of daily training load during the week preceding the match on the risk of sustaining a match injury in professional rugby union. A cohort of 72 players from a single professional French club participated. Global positioning system–derived data including total distance (TD) and high-speed distance in addition to ratings of perceived effort (RPE) for both on- and off-pitch (gym-based strength conditioning work) training were collected for each training session over 3 seasons (2017–2020). The association between the daily measures of external and internal training load over the week preceding the day of the match (MD) and the subsequent risk of injury in match-play was estimated using a mixed-effects logistic model adjusted for contextual and individual factors. A total of 184 injuries were sustained in 128 matches (incidence: 81.2 injuries per 1,000 player hours). Higher RPE values for the strength conditioning session on MD-5 (p < 0.001) and for the on-pitch session on MD-1 (p = 0.04) were associated with an increased risk of injury in matches. On MD-2, a higher TD covered and that run at high speed (>MAS) were, respectively, associated with a higher (p = 0.03) and lower risk (p = 0.02) of injury in matches played. This study in professional rugby union shows that different components of external and internal load had varying influences on injury risk and particularly in relation to the day on which these were performed in the week leading up to the next match. At MD-2, training load favoring intensity rather than volume could reduce the risk of match-play injury.
Fat-Free Mass Index in Sport: Normative Profiles and Applications for Collegiate Athletes
Authors: Jagim Andrew R. , Harty Patrick S. , Jones Margaret T. , Fields Jennifer B. , Magee Meghan , Smith-Ryan Abbie E. , Luedke Joel , Kerksick Chad M. 
Published: July 2024

Abstract
Jagim, AR, Harty, PS, Jones, MT, Fields, JB, Magee, M, Smith-Ryan, AE, Luedke, J, and Kerksick, CM. Fat-free mass index in sport: normative profiles and applications for collegiate athletes. J Strength Cond Res 38(9): 1687–1693, 2024—Recent concerns have been raised regarding the ethical considerations of conducting body composition assessments in sports. Specific apprehensions pertain to the inappropriate use of percent body fat and the limited application of the results to performance and recovery. Fat-free mass index (FFMI), a height-adjusted assessment of FFM, can serve as an alternative body composition metric to focus on in sports. Fat-free mass index provides valuable context regarding an optimal amount of FFM, accounting for skeletal frame and height while helping to qualify an athlete's FFM as low, moderate, or high. This review posits that shifting the focus of body composition measures to FFM can support more ideal targets across athletic seasons, careers, and the return to play after injury. In addition, a FFM focus may help change the perception of body composition assessment and how athletes perceive their current body because of the increased focus on the FFM compartment and the goal of maximizing tissue accrual, rather than focusing on fat loss. Fat-free mass index is calculated by dividing FFM (kg) by height (m2) and can serve to normalize FFM, relative to height, and enable comparisons across athletes, sport types, and sex. Previous research has identified differences in FFMI across sex and among sport categories. Still, there is a need for more published data to develop optimal ranges for FFMI across sex, sports, and positions. As more data become available, FFMI has the potential to provide normative guidelines for optimal FFM development, performance, and injury risk reduction. The purpose of the current review was to summarize FFMI values across collegiate sport categories and competitive status to provide normative profiles, according to sex and sport type.
Intramuscular Hamstring Stiffness Affects Anatomically Modeled Localized Muscle Strain During Passive Hip Flexion
Authors: Rehbein Carlos O. , McDougle Jacob M. , Peñailillo Luis E. , Earp Jacob E. 
Published: July 2024

Abstract
Rehbein, CO, McDougle, JM, Peñailillo, L, and Earp, JE. Intramuscular hamstring stiffness affects anatomically modeled localized muscle strain during passive hip flexion. J Strength Cond Res XX(X): 000–000, 2024—Hamstring strain injuries occur when localized tissue strain capacity is exceeded. Localized strain may be affected by intramuscular variation in stiffness, but research in this area is lacking. The purpose of this study was to determine the effects of intramuscular hamstring stiffness on localized muscle strain during passive hip flexion. Twenty-eight (age 25.0 ± 4.9 years) healthy women (n = 15) and men (n = 13) had biceps femoris, semitendinosus, and semimembranosus stiffness measured proximally, medially, and distally during passive hip flexion and extension using shear-wave elastography. Anthropometric and stiffness measurements were entered into an anatomical model of equivalent springs to estimate localized tissue strain and differentiate between the relative contribution to passive strain from each muscular region. In shortened and stretched positions, stiffness was lowest proximally for all muscles (Cohen's d = 0.66–0.79, p < 0.001). In addition, relative strain contribution was greater proximally (37.5–39.4%) compared with middle (31.74–32.2%) or distal (28.6–30.3%) regions (p < 0.001), with proximal contribution to strain increasing with greater hip flexion. Our results suggest that intramuscular variations in passive hamstring stiffness contribute to inhomogeneous strain throughout the muscle during passive hip flexion. Given the prevalence of proximal stretch-pattern strain injuries, variation in intramuscular stiffness may contribute to risk for such injuries.
Characterization of Health and Safety Resources for Athletes With Sickle Cell Trait at NCAA Institutions
Authors: Yeargin Susan W. , Meyer Courtney M. , Hirschhorn Rebecca M. , Lane Abbi D. , Arent Shawn M. , Haggard Clint R. 
Published: July 2024

AbstractYeargin, SW, Meyer, CM, Hirschhorn, RM, Lane, AD, Arent, SM, and Haggard, CR. Characterization of health and safety resources for athletes with sickle cell trait at NCAA institutions.J Strength Cond ResXX(X): 000–000, 2024—The purpose of this study was to report the prevalence of student-athletes with sickle cell trait (SCT), determine which screening practices are most commonly used, describe the health and human performance services provided to athletes, and ascertain if differences between National Collegiate Athletic Association (NCAA) designations or divisions exist. A cross-sectional survey design was used to query healthcare administrators regarding SCT resources at their institution. The independent variables were designation (historically Black colleges or universities [HBCUs] or non-HBCU) and Division (DI, DII, and DIII). The dependent variables were SCT prevalence, and the health and human performance services provided to athletes. Of the 60 respondents, HBCU (n= 16) reported 4.9 ± 2.7% of athletes with SCT, which was higher than non-HBCU (1.1 ± 0.8%;p= 0.022). Historically Black colleges or university reported a higher percentage of student-athletes supplying their own screening results than non-HBCU (52.5 ± 39.2 vs. 12.9 ± 24.0%;p= 0.022). Division III reported higher proportions of waivers than DI (68.3 ± 38.4 vs. 16.9 ± 31.0%;p= 0.010). Most schools (n= 42, 70.0%) reported having policy and procedures regarding exertional sickling, but none (n= 60, 100.0%) involved strength and conditioning coaches (SCCs) during development. Practically, a greater proportion of DII and DIII institutions do not have supplemental oxygen available compared with DI but not statistically (p= 0.058). Pragmatically, the prevalence should be considered when ordering and preparing resources annually. NCAA institutions need to create policy and procedure sections beyond screening. Athletic trainers and SCCs need to have a strong collaborative relationship to optimize health and human performance services.
HISTORIAS DE LUIS CABRERA DELGADO: NOTAS DE POÉTICA NARRATIVA
Authors: Bolaños Aimée 
Published: July 2024

El presente artículo se interesa por la poética de fabulación fantástica de Luis Cabrera Delgado, cuya obra ocupa un lugar destacado en la literatura infanto-juvenil cubana y latinoamericana. Con este objetivo son leídas tres historias: Tía Julita y Los calamitosos, de modo más general, y detenidamente Carlos, el titiritero, con foco en el proceso de creación artística, la relación del autor con el mundo creado y los lectores. En esta obra se analiza la peculiar composición performativa que integra formas narrativas y dramáticas. La fina y elaborada textura metaficcional desvela sus mecanismos de autoconfiguración, de modo que se asiste al interior de la poiesis a través de un sugestivo juego de espejos y roles actanciales. Ostensivamente el autor se espeja en el narrador y sus personajes, hasta devenir un personaje intratextual. La autoficción especular fantástica permite una compleja visión de mundo que de modo lúdico desenvuelve la reflexión socioética. Las conclusiones caracterizan la poética de la narrativa concebido en nueva escala del imaginario que confiere especial relevancia a los inusitados personajes de estas historias fabulosas, dotadas de tan sugestiva humanidad.
Mitochondrial DNA copy number in monocytes and peripheral blood in patients with systemic sclerosis
Authors: Gerasimova E. V. , Bogatyreva A. I. , Popkova T. V. , Gerasimova D. A. 
Published: July 2024

Innate immune cells are important participants in inflammatory and fibrotic processes in systemic scleroderma (SSc). The pathogenesis of SSc involves immune cells, primarily macrophages, whose disorders are based on mitochondrial cell dysfunction. Mitochondrial DNA (mtDNA) copy number is used as a surrogate marker of mitochondrial cell dysfunction. The aim of the study was to evaluate the number of mtDNA copies in CD14+ monocytes and in all cell populations circulating in the blood in patients with SSc compared to healthy controls.The study included 25 patients with SSc (22 women and 3 men, median age 49 (43-57) years and disease duration 4.6 (1.0-9.6) years) and 25 people without autoimmune diseases or chronic inflammatory diseases matched by age and gender. The majority of patients (80%) had a limited form of SSc. All study participants did not receive antirheumatic therapy. DNA was isolated from CD14+ monocytes and whole blood. Absolute mtDNA copy number was measured using digital PCR. The number of mtDNA copies per cell used for analysis was calculated as the ratio of mtDNA and nDNA copies.It was found that in patients with SSc, the number of mtDNA copies in CD14+ monocytes was higher (108 (60-162) vs 72 (59-79), p = 0.01), and the indicator of all cell populations circulating in the blood did not differ in compared with the control group (109 (72-171) and 128 (85-227), p = 0.17). A negative relationship was found between the number of mtDNA copies and the duration of the disease, and a positive relationship with LPS-stimulated IL-6 secretion by cultured CD14+ monocytes.The study results suggest that increase of mtDNA copy number in CD14+ monocytes is a possible mechanism to maintain the reduced function of defective mitochondria in monocytes from patients with SSc associated with the development and progression of SSc.
Caracterización de lazos parentales en estudiantes de pregrado de la Universidad de Antioquia
Authors: Gómez Maquet Yvonne , Vallejo Zapata Victor Julian , Villada Zapata Johny Andrey , Zambrano Cruz Renato 
Published: July 2024

En el presente artículo se ofrece una caracterización de los lazos parentales en estudiantes de pregrado de la Universidad de Antioquia. Dicha caracterización se realizó con una muestra de 232 personas en edades entre los 16 y los 46 años y se utilizó la prueba Instrumento de Lazos Parentales (Parental Bonding Instrument – P.B.I) en su versión adaptada para población colombiana, desarrollado originalmente por Parker, Tupling & Brown en 1979, y adaptado por Gómez, Vallejo, Villada y Zambrano en 2007. Esta presentación de los resultados de investigación se soporta teóricamente desde la teoría del apego, desarrollada inicialmente por John Bowlby, y pretende aportar información que pueda servir en las diferentes áreas de la intervención en la salud mental.