ABSTRACT Robinson, L, Murray, A, Coughlan, D, Ehlert, A, Heeney, C, Turner, A, and Bishop, C. A 12-week strength and conditioning intervention: An individualized case series approach for 3 amateur and 3 professional female golfers. J Strength Cond Res XX(X): 000-000, 2025-This study used an individualized, case series approach to 12 weeks of strength and conditioning (S&C) training, for 3 high-level amateur and 3 professional female golfers. Each player took part in a 90-minute testing session both pre- and postintervention, and 2 structured S&C sessions per week for 12 weeks. Movement competency assessments were used to help guide exercise selection in each intervention and test measures included golf shot data, the isometric mid-thigh pull, isometric bench press, and countermovement jump, with a total of 12 metrics across the 4 assessment protocols. Analyses of individual performance changes were done by using the SD for each test metric, relative to preintervention scores. Collectively, for the 3 amateur players, 32 out of a possible 36 metrics showed changes > the baseline SD, while for the 3 professional players, 23 metrics elicited changes > the baseline SD. Of note, this collective difference was largely attributable to professional 1, who showed only 4 "true" improvements in test scores, out of a possible 12. This study has shown that taking an individualized approach to S&C training predominantly elicits meaningful changes in both golf shot data and physical performance-a concept that is essential to understand for an individual sport, such as golf.
Abstract Yamashita, Y and Umemura, Y. Effect of high-intensity with short-duration re-warm up on subsequent performance in a cold environment. J Strength Cond Res 38(6): e280–e287, 2024—The aim of this study was to investigate the effect of high-intensity, short-duration re–warm-up (RW) during half time (HT) on subsequent performance in a cold environment. Eleven male subjects (age, 21 ± 2 years; height, 172.4 ± 4.5 cm; body mass, 65.6 ± 7.1 kg; V̇o2max, 47.5 ± 4.8 ml·kg−1·min−1) performed 2 experimental trials comprising 40 minutes of intermittent cycling exercise, which consisted of 15-second rest, 25-second unloading cycling, 10-second high-intensity cycling, and 70-second moderate-intensity cycling as the first half. In the second half, a cycling intermittent-sprint protocol (CISP) was performed, separated by a 15-minute HT period in cold conditions (5 °C, 50% relative humidity). Two experimental trials were included in a random order: (a) approximately 1 minute of high-intensity, short-duration RW (3 sets of 3-second maximal pedaling [body weight × 0.075 kp]) trial high-intensity intermittent cycling trials (HII); (b) 15 minutes of seated rest trial (CON). Cycling intermittent-sprint protocol consisted of 10 sets of a 2-minute exercise protocol, and each set consisted of 10-second rest, 5-second maximal pedaling (body weight × 0.075 kp), and 105-second active recovery at 50% maximum oxygen uptake (V̇o2max). Peak power output of 5-second maximal pedaling during CISP was higher in HII trials than in CON trials (HII: 807 ± 81 W, CON: 791 ± 78 W, p 0.05). These results suggest that high-intensity, short-duration RW may be a useful HT strategy for improving subsequent performance in cold environments.
Este trabajo presenta el proceso de diseño, fabricación y difusión de una estufa de biomasa, destacando el papel crucial de la dinámica de fluidos computacional y la ingeniería asistida por computadora. Además, se ejemplifica cómo la academia puede involucrarse con las comunidades rurales y abordar sus necesidades energéticas. Esta colaboración ilustra el potencial de desarrollar soluciones innovadoras que mejoren la calidad de vida y promuevan el desarrollo sostenible en entornos rurales.
The rapid growth of information and communication technology has also reached the transportation sector, especially in Indonesia. Railway locomotives have experienced significant advancements by transitioning from conventional systems to the use of microcontroller-based sensors. However, to expedite repairs, swift identification of faults is necessary. Railway workers need to continuously improve the quality of human resources and develop application systems to facilitate technicians in identifying issues with CC 201 locomotives. The aim of this research is to build a system that can identify faults and facilitate technicians in diagnosing and providing repair solutions for CC 201 locomotives, using the Case-Based Reasoning method. Research results indicate that this system can be used to diagnose CC 201 locomotive issues based on observed symptoms. Usability testing for 20 respondents using the SUPR-Q method shows an excellent level of system ease and satisfaction, with a score of 90.86%.
Supplemental Digital Content is Available in the Text. Abstract Hanney, WJ, Perez, A, Collado, G, Palmer, AC, Wilson, AT, Richardson, RM, and Kolber, MJ. J Strength Cond Res 38(11): 1854–1859, 2024—Kettlebell swings (KBSs) are commonly used to target the lumbar erector spinae and lower body musculature. This exercise exhibits distinct loading properties that requires cyclical contraction of the trunk extensors and posterior chain, potentially explaining its novel influence on muscle contractility. Tensiomyography (TMG) is a reliable, noninvasive, passive technique that may be used to examine muscular fatigue produced by exercises such as KBSs. The purpose of this randomized control trial was to determine the extent of muscle fatigue in the lumbar erector spinae musculature following the performance of a previously published high-intensity interval KBS protocol. Forty-one adults between the ages of 18 and 45 years were recruited. Inclusion criteria included subjects with no recent history of low back pain and clearance by the physical activity readiness questionnaire. Subjects were randomly allocated to either a KBS group (n = 21) or a control group (CON; n = 20) who only performed the unloaded warm-up. Subjects were assessed at baseline, postintervention, and 24-hours postintervention for bilateral erector spinae fatigue, measured by 5 TMG parameters (Dm, Tc, Tr, Td, and Ts). The results were evaluated through a 2 × 3 (group × time) repeated-measures analysis of variance. The level of significance was set at p ≤ 0.05. There was no significant difference in lumbar erector spinae fatigue, measured by the 5 TMG parameters (p ≥ 0.079), following the interval KBS protocol in comparison with the CON group at 3 assessment periods. A high-intensity interval KBS protocol failed to produce significant differences in erector spinae fatigue compared with the control group that did not perform a KBS. These findings warrant further investigation into muscle fatigue produced with higher intensity protocols and possibly suggest, depending on the programming goals, the need for an alternate KBS training parameters.
Abstract Helén, J, Kyröläinen, H, Ojanen, T, Pihlainen, K, Santtila, M, Heikkinen, R, and Vaara, JP. High-intensity functional training induces superior training adaptations compared with traditional military physical training. J Strength Cond Res 37(12): 2477–2483, 2023—This study examined the effectiveness of concurrent strength and endurance training with an emphasis on high-intensity functional training (HIFT) during military service. Voluntary male conscripts (aged 18–28 years) were placed in either an experimental (EXP: n = 50–66) or a control (CON: n = 50–67) group. The training for the EXP group included HIFT using body mass, sandbags, and kettlebells. The CON group trained according to the current practice. Physical performance and body composition were assessed at baseline (PRE), at week 10 (MID), and after (POST) the 19-week training period. Significance was set at p < 0.05. The total distance covered in a 12-minute running test increased in both groups, but the change in EXP was superior to the change in CON (11.6%, ES: 0.79 vs. 5.7%, ES: 0.33; p = 0.027). Maximal strength and power characteristics increased in EXP (3.1–5.0%), whereas no improvements were observed in CON. Conscripts with the highest initial fitness showed no improvements in physical performance in either group. Body mass and waist circumference decreased in EXP, whereas CON showed an increase in muscle mass. These findings suggest that HIFT is an effective and time-efficient approach to improve soldiers' aerobic fitness during military service. For the optimal development of strength, the training equipment used may not have provided sufficient and progressive loading to yield considerable strength adaptations. More focus should be placed on sufficient intensity and volume in both strength and endurance training, especially for the most fit soldiers.
Abstract Katsoulis, K and Amara, CE. The effects of power training frequency on muscle power and functional performance in older women: a randomized controlled trial. J Strength Cond Res 37(11): 2289–2297, 2023—Low-intensity power training (PT) has emerged as an effective method for improving muscle power and functional performance in older adults. However, effects of low training frequencies are less understood and could expand the repertoire of exercise prescription, particularly in older women who experience greater functional disability with age compared with men. This study investigated the impact of frequency of low-intensity (40% of 1 repetition maximum, 1RM) PT on lower-body power and functional performance in healthy older women. Women (74 ± 4 years) were randomized to 12 weeks of PT of 1 (PT1, n = 14), 2 (PT2, n = 17), or 3 (PT3, n = 17) d·wk−1 or wait control (CON, n = 15). Measures included leg press 1RM, knee extension power (KEP), and functional performance (stair climb power, stair climb time, 30-second chair stands, 400-m walk, Short Physical Performance Battery). There were no differences between the frequency of training in changes in leg press 1RM, KEP, or functional performance after 12 weeks. Pre-post data for individual training groups revealed that leg press 1RM improved in all PT groups (20–33%, p < 0.05). Furthermore, KEP improved in PT2 and PT3 by 10 and 12%, respectively, and all PT groups improved in the 30-second chair stands and Short Physical Performance Battery (6–22%), whereas PT1 and PT3 improved in the 400-m walk and PT2 improved in stair climb power and stair climb time after training (4–7%, p < 0.05). One to 3 weekly low-intensity PT sessions can improve functional performance, although improvements in both functional performance and power might require 2 or 3 sessions per week in older healthy women.
Abstract Niering, M and Muehlbauer, T. Changes after a conventional vs. an alternative therapy program on physical, psychological and injury-related parameters in male youth soccer players with patellar tendinopathy during return to competition. J Strength Cond Res 37(9): 1834–1843, 2023—Changes after a conventional (CON) vs. alternative (ALT) therapy program on physical, psychological, and injury-related or pain-related parameters in soccer players with patellar tendinopathy (PT) during return to competition were examined. Thirty-four male youth soccer players (15–16 years) with PT were randomly assigned to a CON (n = 18) or ALT (n = 16) program. The ALT program consisted of 60 minutes of balance training, eccentric and isometric exercises, static stretching, and a dual-task progression. The CON program consisted of 30 minutes of eccentric and isometric exercises and static stretching. Both programs were conducted until painlessness was reported during full training load. Assessments of muscle power (drop jump, jump and reach), change of direction speed (CODS) (acyclic sprint), speed (tapping, 30-m linear sprint), endurance (Yo-Yo intermittent recovery test level-1), the Achievement Motives Scale Sport, and injury-related or pain-related correlates were performed immediately, 6 weeks, 16 weeks, and 20 weeks after the respective therapy program. Players in the ALT group required a shorter program duration (ALT: 47.1 ± 15.6 days, CON: 58.2 ± 24.6 days) and achieved the same (muscle power, speed, endurance) or greater (CODS) improvements in physical performances, the same enhancements in psychological measures (achievement motives), and better values for injury-related or pain-related correlates (injury incidence, pain-related training interruptions). Results indicate that both programs effectively improve relevant outcome parameters in players with PT. The ALT therapy is more time efficient than the CON therapy. Therapists should consider this multimodal training program for effective treatment of athletes to shorten their return to competition time and minimize the risk of secondary injuries.
Edgar Carlos Quispe Peña, Rolando Rivera Quinto, Marco Espinoza Castillo
et al.
Mejoras en el peso de vellón de sucio (PVe) y diámetro medio de la fibra (DMF) favorece los ingresos de los productores de alpacas; sin embargo, estas variables están relacionadas directamente, complicando el mejoramiento simultáneo de ambas características. Por tanto, se requiere buscar nuevos criterios de selección para la mejora simultánea de ambas características. El propósito del estudio fue caracterizar la densidad de fibras (DenFib), densidad de conductos pilosos (DenCond) y la relación N.° de fibras/conductos (R_Fib/Cond) como posibles criterios de selección. Asimismo, determinar el tipo de relación entre ellas y con el PVe y DMF, y construir y evaluar índices de selección formales bajo escenarios con diferentes mediciones disponibles, considerando en todos los casos PVe y DMF debidamente ponderados por sus pesos económicos, como objetivos de selección. Para ello, se tomaron muestras de fibras, imágenes de piel y se registraron el PVe de alpacas de cuatro rebaños criadas en Huancavelica y Caylloma-Arequipa (Perú) entre 2018 y 2020. Las características de densidad fueron obtenidas mediante el procedimiento denominado Fiber Den, mientras que el DMF se evaluó mediante el FIBER EC, y el PVe se registró con una balanza. En la construcción de los índices de selección para PVe y DMF se aplicó la teoría de índices de selección de Hazel, considerando los valores indicados en la bibliografía y en el presente trabajo. La DenFib, DenCon y R_Fib/Cond varía entre 8.8 a 60 fib/mm2, 3.8 a 21.2 cond/mm2 y 2.0 a 4.3 fib/cond, respectivamente. Se encontraron conductos pilosos de hasta 8 fibras, siendo los más frecuentes los conductos con 1, 2 o 3 fibras. Se concluye que la DenFib y DenCond tienen relación lineal y directa con el PVe e inversa con el DMF, y que la inclusión de la DenFib y DenCond como criterios de selección dentro de un índice de selección mejorarían la exactitud de 0.53 a 0.63, pudiéndose obtener mayores progresos genéticos entre 15 y 18%, con mejores beneficios económicos, que cuando solo se utiliza el PVe y DMF.
María Beatriz Bernabé Loranca, Marco Antonio Rodríguez Flores, Carmen Cerón Garnica
et al.
El particionamiento sobre datos geográficos es de gran utilidad para resolver problemas relacionados con diseño territorial. Para instancias de tamaño pequeño, este problema incluso es resuelto por métodos exactos en un tiempo de respuesta aceptable. Sin embargo, para instancias de tamaño grande y debido a la naturaleza combinatoria de este problema, la complejidad computacional aumenta y el uso de métodos de aproximación se ha hecho necesario. Un caso en particular de este tipo de problemas que ha tenido nuestra atención en los últimos años es el agrupamiento por particiones para AGEBS (áreas geoestadísticas básicas). Algunos trabajos relacionados se han desarrollado para resolver la formación de grupos compactos de AGEBS, pero la incorporación de restricciones adicionales ha sido poco tratada. Un problema interesante de aplicación muy demandado, es la extensión del agrupamiento compacto para construir grupos bajo el criterio de homogeneidad y/o balanceo en el número de objetos que componen los grupos. Este problema se traduce en un problema multiobjetivo, el cual debe lidiar con dos objetivos para conseguir un compromiso entre ambos. Este trabajo presenta un modelo de programación matemática multiobjetivo y su asociada implementación para lograr el equilibrio entre compacidad y homogeneidad en la cardinalidad de objetos. La metaheurística incorporada a este problema de agrupamiento territorial multiobjetivo ha sido búsqueda tabú.
Abstract McNeill, C, Beaven, CM, McMaster, DT, Ward, P, and Gill, N. Eccentric force-velocity-load relationship in trained rugby union athletes. J Strength Cond Res 38(3): 549–555, 2024—The force-velocity relationship is traditionally believed to resemble a hyperbolic shape, known as the “force-velocity curve.” However, there is less evidence regarding this relationship during eccentric muscle action in multijoint isotonic exercise, especially in applied settings. The purpose of this study was to investigate the force-velocity-load relationship in an incremental eccentric back squat test. In addition, 37 professional male rugby union athletes were recruited to participate. Separate generalized linear mixed models were used to analyze the effect of barbell load on relative eccentric peak force (REPF), relative eccentric mean force (REMF), eccentric peak velocity (EPV), and eccentric mean velocity (EMV). A significant effect of load (p < 0.05) was observed for each of the eccentric variables tested. Each increase in barbell load tended to result in a linear increase in REMF and a decrease in EMV and EPV; however, we observed a plateauing effect for REPF as load increased. These results show that for “peak” variables lighter loads produced similar magnitudes of force, but generally moved at higher velocities than heavier loads. These observations suggest that the eccentric force-velocity-load relationship may vary depending on the parameters used. Quantifying rapid, multijoint eccentric performance is justified as it seems to provide valuable insight into individual athletic capability and training program design. Further research may investigate the responsiveness of the qualities to training and the causal nature of eccentric characteristics and athletic performance.
Bret G. Freemyer, D. Beeler, Scott N Crawford
et al.
Supplemental Digital Content is Available in the Text. Abstract Freemyer, B, Beeler, D, Crawford, S, Durkin, R, and Stickley, C. Running alterations pre- and postarthroscopy for femoroacetabular impingement syndrome and labral tears. J Strength Cond Res 38(3): 501–509, 2024—Running is essential to sports participation and activity over the lifespan; however, running biomechanics are not fully described in patients with femoroacetabular impingement (FAIS). The purpose was to compare FAIS patient report outcome surveys (PRO) and running biomechanics preoperatively and 6 months postoperatively with controls. Nineteen subjects (FAIS, n = 10 and age-matched controls, n = 9) were included. The UCLA, Hip Outcome Score activity of daily living (HOSADL) and sports subscale (HOSSS), and 3-D running biomechanics were evaluated. Statistical parametric mapping was conducted on biomechanics data. Statistical significance was set at p ≤ 0.05. Femoroacetabular impingement had similar UCLA activity scores compared with controls by 6 months (FAIS: 8.4 ± 1.7, CON: 8.6 ± 2.0, p = 0.80), despite lower HOSADL (FAIS-Six: 89.3 ± 6.3, CON: 100 ± 0, p = 0.04) and HOSSS (FAIS-Six: 82.6 ± 18.5, CON: 100 ± 0, p = 0.05). The FAIS group had lower knee adduction moments (KAM) around 22–27% of stance (p = 0.05) and lower sagittal plane ankle power generation during the final 5% of stance compared with the controls (p = 0.04) preoperatively. The FAIS also had lower vertical ground reaction forces the first 2% of stance (p = 0.05) and lower KAM from 20 to 30% stance (p = 0.03) at the postoperative time vs. controls. Femoroacetabular impingement had higher hip external rotation angles the first 5% stance (p = 0.05) and the last 20% of stance (p = 0.01) vs. controls. This is the first study to describe FAIS running pre- and postoperatively. Despite higher activity and health 6 months postarthroscopy, the patients with FAIS had altered running biomechanics. Clinicians should consider these findings when creating rehabilitation protocols and during running progressions across the postoperative care of patients with FAIS.
Abstract Lum, D, Joseph, R, Ong, KY, Tang, JM, and Suchomel, TJ. Comparing the effects of long-term vs. periodic inclusion of isometric strength training on strength and dynamic performances. J Strength Cond Res 37(2): 305–314, 2023—This study compared the effects of including isometric strength training (IST) for consecutive 24 weeks (CIST) against a periodic inclusion (PIST) of this mode of training on strength and dynamic performances. Twenty-four floorball athletes (age: 23 ± 2.7 years, stature: 1.74 ± 2.08 m, and body mass: 72.7 ± 14.4 kg) were randomly assigned to the control (CON), CIST, or PIST group. Athletes completed 20-m sprint, countermovement jump (CMJ), and isometric midthigh pull (IMTP) during pre-test and were tested on weeks 6, 12, 18, and 24. All groups performed a similar strength training program twice per week. However, 2 sets of squats were replaced with isometric squat in CIST for all 24 weeks but only on weeks 1–6 and 13–18 for PIST. A significant main effect for time was observed for 5-, 10-, and 20-m sprint time, CMJ height, peak force, peak power, time to take-off, modified reactive strength index, IMTP peak force, relative peak force, and force at 200 milliseconds (p = <0.001–0.037). Isometric strength training for 24 consecutive weeks resulted in greater improvement in 5-m sprint time than CON at week 24 (p = 0.024, g = 1.17). Both CIST and PIST resulted in greater improvements in 10-m sprint time than CON at various time points (p = 0.007–0.038 and 0.038, g = 1.07–1.44 and 1.18, respectively). Isometric strength training for 24 consecutive weeks and PIST resulted in greater improvements in 20-m sprint time than CON at week 6 (p = 0.007 and 0.025, g = 1.65 and 1.40, respectively). The results showed that the inclusion of IST resulted in greater improvements in sprint performance than CON but no significant difference in all measured variables with PIST.
S. Bartolomei, Riccardo De Luca, Samuele M. Marcora
Abstract Bartolomei, S, De Luca, R, and Marcora, SM. May a nonlocalized postactivation performance enhancement exist between the upper and lower body in trained men? J Strength Cond Res 37(1): 68–73, 2023—The aim of this study was to establish whether a resistance exercise for the upper body may generate a postactivation performance enhancement (PAPE) in the lower body. Thirteen resistance-trained men (age = 26.4 ± 3.3 years, body mass = 76.9 ± 6.3 kg, and height = 177.6 ± 5.2 cm) participated in the present investigation and were tested for upper-body and lower-body power (bench press throw and countermovement jump power [CMJP] tests). Subjects were also tested for maximum force and electromyographic (EMG) activation of quadriceps muscles while performing an isometric leg extension. All assessments were performed before and 8 minutes after a high-intensity (HI: 5 sets of 1 rep at 90% of 1 repetition maximum [1RM]) bench press protocol, a high-power protocol (POW: 5 sets of 1 rep at 30% of 1RM with maximum explosive intent), and a control trial (CON). Subjects performed all trials in a randomized order and on different days. A significant trial × time interaction was detected for CMJP (p = 0.049). This parameter was significantly increased following the HI protocol only (p = 0.024). A significant interaction was also noted for EMG with a significant improvement following the HI protocol (p = 0.032) and a significant decrease following the POW protocol (p = 0.020). No other significant effects were detected (p > 0.05). The results of this investigation indicate that a HI bench press protocol may produce a PAPE in the lower-body power and increase the neuromuscular activation of leg extensor muscles. The POW bench press protocol did not show any positive effects on lower-body performance. Athletes and practitioners may take advantage from the inclusion of upper-body HI resistance exercises throughout complex resistance workouts to improve lower-body power output.
La pandemia de COVID-19 ha cambiado la agenda de la educación matemática. Este cambio se analizará examinando tres tendencias en educación matemática: el uso detecnología digital, la filosofía de la educación matemática y la educación matemática crítica. La tecnología digital se convirtió en una tendencia en la educación matemática en respuesta a la llegada de un artefacto diferente al aula de matemática. Se puso en el punto de mira cuando la pandemia trasladó repentinamente las aulas a la modalidad online en todo elmundo. En este contexto, hay que abordar retos específicos para la educación matemática. El vínculo entre la pandemia de COVID-19 y la tecnología digital en la educación también plantea cuestiones epistemológicas destacadas por la filosofía de la educación matemática y la educación matemática crítica. Utilizando la idea de que la unidad básica de producción de conocimiento a lo largo de la historia es humanos-con-medios, discuto cómo los seres humanos están conectados con el virus, cómo se ha puesto al descubierto la desigualdad social y cómo cambiarán las agendas de estas tres tendencias en la educación matemática. Destaco la urgente necesidad de estudiar cómo ocurre la educación matemática online para los niños, situación en la cual el entorno doméstico y las desigualdades en el acceso a las tecnologías digitales asumen papeles tan significativos. Tenemos que entender el papel político de la agencia de artefactos tales como el hogar, en colectivos de humanos-con-medios-cosas, y por último necesitamos aprender cómo implementar un curriculum que aborde las desigualdades sociales. Este debate se articula con ejemplos.
En este trabajo se describe una experiencia áulica desarrollada con futuros profesores de matemática, con el objetivo de generar la posibilidad de que los estudiantes tengan la oportunidad de desarrollar procesos de formulación y contrastación de conjeturas durante su formación disciplinar. Las intervenciones del docente y de los alumnos permiten avanzar en la formulación de conjeturas con creciente grado de generalidad. En el ejemplo presentado, las conjeturas formuladas se demuestran mediante una actividad de justificación desarrollada a partir de las interacciones entre el docente y los alumnos. Se ponen de manifiesto algunas de las dificultades inherentes a este tipo de trabajo, como por ejemplo la posibilidad de que algunas discusiones no puedan ser seguidas por todos los alumnos, cuestión que se agudiza cuando se trata de cursos numerosos. Más allá de estas limitaciones, la experiencia se valora como muy fructífera para todos los participantes, lo que conduce a subrayar la pertinencia de que los futuros profesores puedan familiarizarse con este tipo de trabajo durante su formación inicial.