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1.
Sci Rep ; 14(1): 19201, 2024 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-39160232

RESUMEN

Supraphysiological doses of anabolic-androgenic steroids (AAS) is popular among recreational weightlifters and bodybuilders due to the performance-enhancing properties but is also associated with adverse cardiovascular effects. The knowledge about how AAS affect the vasculature is limited, although results from previous studies suggest alterations in vasoreactivity and morphology. In the present study we investigate the association between long-term use of AAS and vascular function. Hundred and twenty-three males were included in the study, 56 of them current AAS users and 67 weightlifting controls. Vascular function was evaluated by carotid artery reactivity and flow-mediated dilation. AAS users had significantly reduced carotid artery reactivity (p < 0.001) and flow-mediated dilation (p < 0.001) compared to weightlifting controls. Results from the present study indicate that long-term use of AAS affect the cardiovascular system negatively, measured as reduced carotid artery reactivity and flow-mediated dilation. These findings could partly explain sudden cardiovascular events among young long-term users of AAS.


Asunto(s)
Anabolizantes , Humanos , Masculino , Anabolizantes/efectos adversos , Anabolizantes/administración & dosificación , Adulto Joven , Adulto , Arterias Carótidas/efectos de los fármacos , Andrógenos/efectos adversos , Andrógenos/administración & dosificación , Andrógenos/farmacología , Levantamiento de Peso , Vasodilatación/efectos de los fármacos , Esteroides/efectos adversos , Adolescente
2.
PLoS One ; 19(8): e0308344, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39110682

RESUMEN

Barbell squats are commonly utilized in resistance training for rehabilitation, daily living enhancement, and improving sports performance. The current study investigated the kinematic and electromyographic (EMG) parameters in the squat between sexes across different repetition ranges (1-, 3-, 6-, and 10-RM) among recreationally strength-trained subjects. A total of 26 subjects (13 men: age 25 ± 3.5 years, height 178.2 ± 5.8 cm, weight 82.3 ± 9.1 kg; 13 women: age 24 ± 4.1 years, height 165.4 ± 6.3 cm, weight 68.2 ± 8.7 kg) participated in the study. The level of significance was set at p<0.05. The findings revealed no sex-specific differences in average barbell velocity across repetition ranges. However, the 1-RM showed a significantly lower average velocity compared to the final repetition of other repetition ranges (p<0.001), with the last repetition at 10-RM revealing a significantly higher velocity (p<0.001). Women had greater maximal angular hip extension velocity in the final repetitions of the 6- and 10-RM (p≤0.035, ηp2≤0.20), while both sexes displayed lower maximal angular knee extension velocity in the final repetition of the 10-RM (p = 0.028, ηp2 = 0.15). Moreover, men had lower EMG amplitude in the rectus femoris (3- and 10-RM), soleus, and lateral vastus (10-RM) compared to women (p≥0.011, ηp2≥0.26). It was concluded that 10-RM differed greatly in kinematics and EMG, suggesting different fatigue mechanisms compared to other repetition ranges with heavier loads. Furthermore, sex differences in EMG and angular hip extension velocity might imply sex-specific fatiguing mechanisms during high-repetition squats. These considerations could be important when prescribing training programs.


Asunto(s)
Electromiografía , Entrenamiento de Fuerza , Humanos , Masculino , Electromiografía/métodos , Femenino , Adulto , Fenómenos Biomecánicos , Adulto Joven , Entrenamiento de Fuerza/métodos , Levantamiento de Peso/fisiología , Músculo Esquelético/fisiología , Factores Sexuales , Caracteres Sexuales , Fuerza Muscular/fisiología
3.
Ann Med ; 56(1): 2383965, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-39078324

RESUMEN

BACKGROUND: The movement of the barbell has been detected as success factor for the snatch and the clean and jerk events. As the barbell's movement has been shown to be related to the athlete's body movement, we hypothesized that the latter could be a success factor also for the back squat (BS) event. Hence, this study aimed to investigate postural control during the execution of the BS at different load intensities in powerlifters and weightlifters. METHODS: Seventeen powerlifters and weightlifters were enrolled and the one-repetition maximum (1-RM) of the BS of each participant was measured. Afterwards, the assessment of postural control during the execution of the BS at different load intensities (i.e. 60%, 70%, 80%, 90%, 100%) of the 1-RM of each participant was carried out through a posturographic platform to measure the displacement of the centre of pressure (CoP). The following parameters were considered: sway path length (SPL), sway ellipse surface (SES), length/surface (LFS ratio), sway mean speed (SMS), CoP coordinates along X and Y planes. RESULTS: We found a significant increase in SPL and LFS ratio, and a significant decrease in SMS as the load intensity increased. In detail, we detected a significant difference in: (a) SPL between the BS at 60% and 80%, 60% and 90%, 60% and 100%; between the BS at 70% and 90%, 70% and 100%; between the BS at 80% and 100%; and between the BS at 90% and 100%; (b) SMS between the BS at 60% and 80%, 60% and 90%; (c) LFS ratio between the BS at 60% and 90%, 60% and 100%. CONCLUSIONS: These results suggest that powerlifters and weightlifters adopt different postural control strategies depending on the load intensity when performing the BS. Our findings showed that higher effort could affect postural control during the BS. Thus, postural control could be considered a success factor for the BS.


Asunto(s)
Equilibrio Postural , Levantamiento de Peso , Humanos , Levantamiento de Peso/fisiología , Equilibrio Postural/fisiología , Masculino , Adulto , Adulto Joven , Atletas , Soporte de Peso/fisiología , Movimiento/fisiología , Femenino , Postura/fisiología , Entrenamiento de Fuerza/métodos
4.
JAMA ; 332(5): 363, 2024 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-38995661
5.
Nutrients ; 16(13)2024 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-38999769

RESUMEN

Caffeine is a well-described ergogenic aid used to enhance athletic performance. Using animal models can greatly increase our understanding of caffeine's mechanisms in performance. Here, we adapted an animal weight-lifting exercise model to demonstrate caffeine's ergogenic effect in rats. Male Wistar rats (315 ± 35 g) were randomly divided into two groups: one group received 5 mg·kg-1 of caffeine (0.5 mL; CEx; n = 5) and the other 0.9% NaCl (0.5 mL; PEx; n = 4) through an orogastric probe (gavage) one hour before exercise. Weight-lifting exercise sessions were performed over three subsequent days, and the number of complete squats performed was counted. Analyses of the area under the curve in all three experiments showed that the CEx group responded more to stimuli, performing more squats (1.7-, 2.0-, and 1.6-fold; p < 0.05) than the control group did. These three days' data were analyzed to better understand the cumulative effect of this exercise, and a hyperbolic curve was fitted to these data. Data fitting from the caffeine-supplemented group, CEx, also showed larger Smax and Kd (2.3-fold and 1.6-fold, respectively) than the PEx group did. Our study demonstrated an acute ergogenic effect of caffeine in an animal weight-lifting exercise model for the first time, suggesting potential avenues for future research.


Asunto(s)
Cafeína , Ratas Wistar , Levantamiento de Peso , Animales , Cafeína/farmacología , Cafeína/administración & dosificación , Masculino , Proyectos Piloto , Ratas , Levantamiento de Peso/fisiología , Condicionamiento Físico Animal/fisiología , Sustancias para Mejorar el Rendimiento/farmacología , Sustancias para Mejorar el Rendimiento/administración & dosificación
6.
J Sports Med Phys Fitness ; 64(7): 640-649, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38916087

RESUMEN

BACKGROUND: The analysis of athletic performance has always aroused great interest from sport scientist. This study utilized machine learning methods to build predictive models using a comprehensive CrossFit (CF) dataset, aiming to reveal valuable insights into the factors influencing performance and emerging trends. METHODS: Random forest (RF) and multiple linear regression (MLR) were employed to predict performance in four key weightlifting exercises within CF: clean and jerk, snatch, back squat, and deadlift. Performance was evaluated using R-squared (R2) values and mean squared error (MSE). Feature importance analysis was conducted using RF, XGBoost, and AdaBoost models. RESULTS: The RF model excelled in deadlift performance prediction (R2=0.80), while the MLR model demonstrated remarkable accuracy in clean and jerk (R2=0.93). Across exercises, clean and jerk consistently emerged as a crucial predictor. The feature importance analysis revealed intricate relationships among exercises, with gender significantly impacting deadlift performance. CONCLUSIONS: This research advances our understanding of performance prediction in CF through machine learning techniques. It provides actionable insights for practitioners, optimize performance, and demonstrates the potential for future advancements in data-driven sports analytics.


Asunto(s)
Rendimiento Atlético , Levantamiento de Peso , Humanos , Aprendizaje Automático , Conjuntos de Datos como Asunto , Bosques Aleatorios , Adulto , Análisis de Datos , Masculino , Femenino
7.
J Strength Cond Res ; 38(7): 1221-1230, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38900172

RESUMEN

ABSTRACT: Larsen, S, de Zee, M, Kristiansen, EL, and van den Tillaar, R. A biomechanical comparison between a high and low barbell placement on net joint moments, kinematics, muscle forces, and muscle-specific moments in 3 repetition maximum back squats. J Strength Cond Res 38(7): 1221-1230, 2024-This study aimed to investigate the impact of a high barbell vs. low barbell placement on net joint moments, muscle forces, and muscle-specific moments in the lower extremity joints and muscles during maximum back squats. Twelve recreationally trained men (age = 25.3 ± 2.9 years, height = 1.79 ± 7.7 m, and body mass = 82.8 ± 6.9 kg) volunteered for the study. A marker-based motion capture system and force plate data were used to calculate the net joint moments, and individual muscle forces were estimated using static optimization. Muscle forces were multiplied by their corresponding internal moment arms to determine muscle-specific moments. Statistical parametric mapping was used to analyze the effect of barbell placement as time-series data during the concentric phase. The 3 repetition maximum barbell load lifted by the subjects was 129.1 ± 13.4 kg and 130.2 ± 12.7 kg in the high bar and low bar, which were not significantly different from each other. Moreover, no significant differences were observed in net joint moments, muscle forces, or muscle-specific moments for the hip, knee, or ankle joint between the low- and high bar placements. The findings of this study suggest that barbell placement plays a minor role in lower extremity muscle forces and moment-specific moments when stance width is standardized, and barbell load lifted does not differ between barbell placements among recreationally resistance-trained men during maximal back squats. Therefore, the choice of barbell placement should be based on individual preference and comfort.


Asunto(s)
Músculo Esquelético , Humanos , Masculino , Fenómenos Biomecánicos , Músculo Esquelético/fisiología , Adulto , Adulto Joven , Articulación del Tobillo/fisiología , Articulación de la Cadera/fisiología , Articulación de la Rodilla/fisiología , Levantamiento de Peso/fisiología , Fuerza Muscular/fisiología , Entrenamiento de Fuerza/métodos , Equipo Deportivo
8.
J Strength Cond Res ; 38(7): 1213-1220, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38900171

RESUMEN

ABSTRACT: McMahon, G. No effect of interset palm cooling on acute bench press performance, neuromuscular or metabolic responses, following moderate-intensity resistance exercise. J Strength Cond Res 38(7): 1213-1220, 2024-Despite the growing literature in high-intensity exercise regarding palm cooling, the acute effects of palm cooling on exercise performance indices, neuromuscular and metabolic responses, have not been described during moderate-intensity resistance exercise. Nine (age, 22 ± 1 year; mass, 80.8 ± 16.2 kg; height, 1.80 ± 0.11 m) healthy, male (n = 7) and female (n = 2) resistance-trained subjects performed 4 sets of bench press to failure at 60% 1 repetition maximum with 3-minute passive recovery. Subjects were randomly allocated to either the cooling (COL; 2 minutes of cooling at 10 °C) or the control (passive rest; CON) condition separated by 1 week between the conditions. Exercise performance (volume load, repetitions, barbell velocity), muscle activation, blood lactate, and rate of perceived exertion were assessed. Despite changes across the variables during the resistance exercise sessions, there were no statistical differences (p > 0.05) in any of the performance, neuromuscular or physiological responses, between the 2 experimental conditions, despite palm temperature being significantly (p < 0.001) reduced in the cooling condition compared with control throughout. Therefore, based on the results of this study, palm cooling does not enhance acute moderate-intensity resistance exercise.


Asunto(s)
Ácido Láctico , Músculo Esquelético , Entrenamiento de Fuerza , Humanos , Masculino , Entrenamiento de Fuerza/métodos , Adulto Joven , Femenino , Músculo Esquelético/fisiología , Ácido Láctico/sangre , Mano/fisiología , Levantamiento de Peso/fisiología , Frío , Rendimiento Atlético/fisiología , Fuerza Muscular/fisiología , Esfuerzo Físico/fisiología , Electromiografía , Adulto
9.
J Strength Cond Res ; 38(7): 1321-1325, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38900178

RESUMEN

ABSTRACT: Suchomel, TJ, Techmanski, BS, Kissick, CR, and Comfort, P. Can the velocity of a 1RM hang power clean be used to estimate a 1RM hang high pull? J Strength Cond Res 38(7): 1321-1325, 2024-The purpose of this study was to estimate the 1-repetition maximum hang high pull (1RM HHP) using the peak barbell velocity of a 1RM hang power clean (HPC). Fifteen resistance-trained men (age = 25.5 ± 4.5 years, body mass = 88.3 ± 15.4 kg, height = 176.1 ± 8.5 cm, relative 1RM HPC = 1.3 ± 0.2 kg·kg-1) with previous HPC experience participated in 2 testing sessions that included performing a 1RM HPC and HHP repetitions with 20, 40, 60, and 80% of their 1RM HPC. Peak barbell velocity was measured using a linear position transducer during the 1RM HPC and HHP repetitions performed at each load. The peak barbell velocity achieved during the 1RM HPC was determined as the criterion value for a 1RM performance. Subject-specific linear regression analyses were completed using slope-intercept equations created from the peak velocity of the 1RM HPC and the peak barbell velocities produced at each load during the HHP repetitions. The peak barbell velocity during the 1RM HPC was 1.74 ± 0.30 m·s-1. The average load-velocity profile showed that the estimated 1RM HHP of the subjects was 98.0 ± 19.3% of the 1RM HPC. Although a 1RM HHP value may be estimated using the peak barbell velocity during the HPC, strength and conditioning practitioners should avoid this method because of the considerable variation within the measurement. Additional research examining different methods of load prescription for weightlifting pulling derivatives is needed.


Asunto(s)
Fuerza Muscular , Entrenamiento de Fuerza , Levantamiento de Peso , Humanos , Masculino , Entrenamiento de Fuerza/métodos , Adulto , Levantamiento de Peso/fisiología , Adulto Joven , Fuerza Muscular/fisiología
10.
J Strength Cond Res ; 38(7): e341-e348, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38900182

RESUMEN

ABSTRACT: Scott, KM, Kreisel, BR, Florkiewicz, EM, Crowell, MS, Morris, JB, McHenry, PA, and Benedict, TM. The effect of cautionary versus resiliency spine education on maximum deadlift performance and back beliefs: A randomized control trial. J Strength Cond Res 38(7): e341-e348, 2024-The purpose of this study was to determine the effect of cautionary information about the spine vs. a message of spine resiliency on maximum deadlift (MDL) performance and beliefs regarding the vulnerability of the spine. This cluster randomized control trial involved 903 military new cadets (n = 903) during their mandatory fitness test in cadet basic training (mean age 18.3 years, body mass index 23.8 kg·m-2, 22% female). Subjects were cluster randomized to 3 groups. The cautionary group received a message warning them to protect their backs while deadlifting, the resiliency group received a message encouraging confidence while deadlifting, and the control group received the standardized Army deadlift education only. The outcome measures were MDL weight lifted and perceived spine vulnerability. Significance was set at alpha ≤0.05. There were no between-group differences in weight lifted (p=0.40). Most subjects believed that the spine is vulnerable to injury. Three times as many subjects who received the resiliency education improved their beliefs about the vulnerability of their spines compared with those receiving the cautionary education (p<0.001). This study demonstrated the potential for brief resiliency education to positively influence beliefs about spine vulnerability, whereas cautionary education did not impair performance.


Asunto(s)
Personal Militar , Humanos , Femenino , Masculino , Personal Militar/psicología , Adolescente , Adulto Joven , Levantamiento de Peso/fisiología , Levantamiento de Peso/psicología , Traumatismos de la Espalda/prevención & control , Columna Vertebral/fisiología , Adulto
11.
Steroids ; 209: 109465, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38945388

RESUMEN

Anabolic-androgenic steroids (AAS) are used widely, but in illegal ways mostly by young men as performance-enhancing and image-enhancing drugs (IPED). long-term usage of AAS, usually in conjunction with other illegal substances, can have extremely detrimental impacts on the reproductive system. The primary goal of this study was to examine any possible detrimental effects of AAS on sex hormone levels, a liver and kidney function in individuals who frequent fitness centers in Iraq-Baghdad. In this research, there are 60 participants (20-37 years old); 30 athletes who visited the different gyms in Baghdad/ Iraq and used AAS such as testosterone, Boldenone, Cybontae, Deca Durabellin; and 30 athletes who did not take any synthetics hormones and serve as control. All participants answered the questionnaire form which included their age, the type of used AAS, when they started to take it, and the total usage number per week. The blood (5 ml) was drawn from every participant to separate the serum. The serum was used to measure some hormones (Testosterone, FSH, LH, prolactin and Estrodiol) and liver and kidney function parameters. The results showed a significantly lower level of testosterone and FSH in the AAS-users' bodybuilding group compared to the control group. In comparison with the control group, there was a notable rise in the PRL level in the serum of AA users. However, when comparing the serum levels of LH and Estrodiol in the AAS-user group to those in the control group, no discernible variations were seen. AAS users had a significantly higher level of ALT and lower ALP than controls, although there is no difference in AST levels between the two groups. The creatine level was significantly higher in the AAS-user compared to the control group, but not urea. In conclusion, the effects of AAS and other supplements on sex hormones and kidney, liver function, and vary depending on how long they are used, with the effects of AAS being more pronounced. Therefore, there is a need for culturally sensitive measures to prevent steroid abuse among youth.


Asunto(s)
Anabolizantes , Humanos , Masculino , Adulto , Adulto Joven , Anabolizantes/efectos adversos , Irak , Testosterona/sangre , Levantamiento de Peso , Atletas , Hígado/efectos de los fármacos , Hígado/metabolismo , Riñón/efectos de los fármacos , Riñón/metabolismo , Esteroides/efectos adversos , Congéneres de la Testosterona/efectos adversos , Congéneres de la Testosterona/sangre , Esteroides Anabólicos Androgénicos
12.
J Strength Cond Res ; 38(8): 1366-1371, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38888595

RESUMEN

ABSTRACT: Dhahbi, W, Padulo, J, Russo, L, Racil, G, Ltifi, M-A, Picerno, P, Iuliano, E, and Migliaccio, GM. Four- to 6-repetition maximum and 1-repetition maximum estimation in free-weight bench press and smith machine squat based on body mass in male athletes. J Strength Cond Res 38(8): 1366-1371, 2024-This study aimed to explore the feasibility and face validity of predicting maximum strength 1 repetition maximum (1-RM) and 4-6 RM in athletes across different sports specialties, based on the relationship between muscle strength and BM. One hundred fifteen male athletes, aged 23.63 ± 6.77 years and participating in diverse sports specialties, were included in this study. Muscle strength was assessed using the 4-6 RM and 1-RM tests in free-weight bench press (BP) and Smith machine squat (SQ) exercises, whereas BM was measured using a portable digital scale. A linear regression equation based on muscle strength and BM was performed. The 4-6 RM and 1-RM scores showed excellent intersession relative reliability (intraclass correlation coefficient (2,1) : 0.946-0.989) and absolute reliability (CV: 3.4-4.7%) in both BP and SQ exercises. In addition, the magnitude of the relationship and the coefficients used to estimate the 4-6 RM and 1RM, based on BM, differed among the subjects when they are grouped according to their sports specialties ( R2 ranged from non-significant to 0.998). Overall, the 4-6 RM test showed a stronger correlation with BM ( R : 0.655 for SQ and R : 0.683 for BP) than the 1RM ( R : 0.552 for SQ and R : 0.629 for BP), and the general (i.e., not sport-specific) 4 to 6-RM prediction equations should be preferred over sport-specific ones because they are statistically more robust due to the larger sample size. In conclusion, the 4-6 RM can be predicted from BM with high reliability, a moderate association, and a prediction error that, when considering the 4-6 RM as a starting point for estimating of the 1RM, can be considered entirely acceptable in practical settings.


Asunto(s)
Atletas , Fuerza Muscular , Levantamiento de Peso , Humanos , Masculino , Fuerza Muscular/fisiología , Levantamiento de Peso/fisiología , Adulto Joven , Adulto , Reproducibilidad de los Resultados , Entrenamiento de Fuerza/instrumentación , Entrenamiento de Fuerza/métodos , Índice de Masa Corporal , Adolescente
13.
Eur J Sport Sci ; 24(6): 732-739, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38874957

RESUMEN

Perception of Velocity (PV) is the ability to estimate single repetition velocity during resistance training (RT) exercises. The main purpose of the study was to evaluate the effects of Mental Fatigue (MF) on the accuracy of barbell PV. The secondary aims were to evaluate whether MF affected RT performance and ratings of perceived exertion (RPE; OMNI-RES) in the back squat. Twenty-four (14 Females, 10 Males) resistance-trained participants underwent 2 familiarization sessions and 1RM test for the back squat. In two separate sessions, PV was tested for light, medium, and heavy loads in 2 conditions in random order: at rest (REST) and in MF condition (POST-MF) induced by previous incongruent Stroop color-word task. MF and Motivation were assessed through visual analog scales (VAS; 0-100) before and after the Stroop task. For each load subjects performed 2 repetitions and reported the RPE value. Mean propulsive velocity (Vr) of the barbell was recorded with a linear encoder, while the perceived velocity (Vp) of the subjects was self-reported using the Squat-PV scale. The PV accuracy was calculated through the delta score (ds: Vp-Vr). Following the Stroop task MF increased significantly (p < 0.001; F (1, 23) = 52.572), while motivation decreased (p < 0.05; F (1, 23) = 7.401). Ds, Vr, and RPE did not show significant differences between conditions (p > 0.05) for the three loads analyzed. MF induced by previous demanding cognitive task did not affect PV accuracy. Furthermore, subjects maintained unchanged both RT performance and RPE values associated with each load, even when mentally fatigued.


Asunto(s)
Fatiga Mental , Entrenamiento de Fuerza , Humanos , Masculino , Femenino , Entrenamiento de Fuerza/métodos , Adulto Joven , Adulto , Percepción/fisiología , Esfuerzo Físico/fisiología , Test de Stroop , Motivación , Levantamiento de Peso/fisiología , Levantamiento de Peso/psicología
14.
Int J Sports Physiol Perform ; 19(7): 685-695, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38772547

RESUMEN

PURPOSE: To examine the sex differences in performance and perceived fatigue during resistance training prescribed using traditional (TRA) and autoregulation rest-redistribution training (ARRT) approaches. METHODS: Twelve resistance-trained men and 12 women completed 2 sessions including the bench-press exercise matched for load (75% of 1-repetition maximum), volume (24 repetitions), and total rest (240 s). Sessions were performed in a counterbalanced randomized design with TRA consisting of 3 sets of 8 repetitions with 120-second interset rest and ARRT employing a personalized combination of clusters, repetitions per cluster, and between-clusters rest regulated with a 20% velocity-loss threshold. The effects of TRA and ARRT on velocity loss, unilateral isometric peak force, and rating of fatigue (ROF) were compared between sexes. RESULTS: The velocity loss was generally lower during ARRT compared with TRA (-0.47% [0.11%]), with velocity loss being mitigated by ARRT to a greater extent among males compared with females (-0.37% [0.15%]). A smaller unilateral isometric peak force decline was observed after ARRT than TRA among males compared with females (-38.4 [8.4] N). Lower ROF after ARRT than TRA was found among males compared to females (-1.97 [0.55] AU). Additionally, males reported greater ROF than females across both conditions (1.92 [0.53] AU), and ARRT resulted in lower ROF than TRA overall (-0.83 [0.39] AU). CONCLUSIONS: The ARRT approach resulted in decreased velocity loss, peak force impairment, and ROF compared with TRA in both sexes. However, male subjects exhibited more pronounced acute within-session benefits from the ARRT method.


Asunto(s)
Fatiga Muscular , Entrenamiento de Fuerza , Descanso , Humanos , Masculino , Femenino , Entrenamiento de Fuerza/métodos , Fatiga Muscular/fisiología , Adulto Joven , Factores Sexuales , Descanso/fisiología , Adulto , Percepción/fisiología , Homeostasis , Fuerza Muscular/fisiología , Contracción Isométrica/fisiología , Músculo Esquelético/fisiología , Levantamiento de Peso/fisiología
15.
J Sport Rehabil ; 33(5): 333-339, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38734422

RESUMEN

INTRODUCTION: Unlike the most common training approaches for bodybuilding, powerlifting programs are generally based on maximum and submaximal loads, putting enormous stresses on the lumbar spine. The flexion relaxation phenomenon evaluation is a clinical tool used for low back pain (LBP) assessment. This study aimed to evaluate the role of the flexion relaxation phenomenon in the analysis of LBP in the powerlifters. METHODS: Healthy professional powerlifters participated in the study. In fact, we divided the participants into a LBP-low-risk group and a LBP-high-risk group, based on a prior history of LBP. Outcome measures included flexion relaxation ratio (FRR) and trough surface electromyography collected during trunk maximum voluntary flexion; furthermore, during a bench press lifting, we measured the height of the arched back (ARCH), using a camera and the Kinovea video editing software, to consider a potential correlation with the risk of LBP. RESULTS: We included a group of 18 male (aged 24-39 y) powerlifters of 93 kg category. We measured a nonsignificant mean difference of ARCH between low-risk LBP group and high-risk LBP subjects. Curiously, maximum voluntary flexions were both above the threshold of 3.2 µV; therefore, with an absence of appropriate myoelectric silence, on the contrary, the FRR ratios were higher than 9.5, considering the presence of the phenomenon, exclusively for the low-risk group. The lumbar arched back measurement data did not report any association with the LBP risk, regarding the maximum voluntary flexion value, and even more than the FRR there is a relationship with the presence or the absence of LBP risk. CONCLUSIONS: FRR could be considered as a useful parameter for studying the risk of LBP in powerlifting. The FRR index not only refers to the possible myoelectric silence of the lumbar muscles in trunk maximum forward flexion but also takes into account the energy value delivered by the lumbar muscles during the flexion. Furthermore, we can indicate that the size of the powerlifter ARCH may not be a determining factor in the occurrence of LBP.


Asunto(s)
Electromiografía , Dolor de la Región Lumbar , Levantamiento de Peso , Humanos , Dolor de la Región Lumbar/fisiopatología , Masculino , Adulto , Levantamiento de Peso/fisiología , Adulto Joven , Prueba de Estudio Conceptual
16.
J Strength Cond Res ; 38(6): 1019-1024, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38781465

RESUMEN

ABSTRACT: Sweet, DK, Qiao, J, Rosbrook, P, and Pryor, JL. Load-velocity profiles before and after heated resistance exercise. J Strength Cond Res 38(6): 1019-1024, 2024-This study examined neuromuscular performance using load-velocity (L-V) profiles in men and women before and after resistance exercise (RE) in hot (HOT; 40° C) and temperate (TEMP; 21° C) environments. Sixteen (f = 8, m = 8) resistance-trained individuals completed a single 70-minute whole-body high-volume load (6 exercises, 4 sets of 10 repetitions) RE bout in HOT and TEMP. Before and after RE, rectal temperature (TRE), muscle temperature of the vastus lateralis (TVL) and triceps brachii (TTB), and an L-V profile for the deadlift and bench press were recorded. Thermoregulatory and L-V data were analyzed using separate 2-way repeated measures analysis of variances (ANOVAs; condition [hot, temperate] and time [pre, post]) with significance level set at p ≤ 0.05. Deadlift peak velocity was reduced at 60% 1 repetition maximum (1RM) after RE in HOT but not TEMP. Peak velocity of 40% 1RM bench press was lower in TEMP vs. HOT pre-RE (p < 0.01). Peak velocity was decreased at all loads in the deadlift L-V profile after RE, regardless of condition. Despite elevated TRE (TEMP; 37.58 ± 0.35, HOT; 38.20 ± 0.39° C), TVL (TEMP; 35.24 ± 0.62, HOT; 37.92 ± 0.55° C), and TTB (TEMP; 35.05 ± 0.78, HOT; 38.00 ± 0.16° C) after RE in HOT vs. TEMP (p < 0.01), RE in HOT did not broadly affect L-V profiles. This indicates heated resistance exercise can be performed with high-volume load and high ambient temperature with minimal performance impairment.


Asunto(s)
Calor , Músculo Esquelético , Entrenamiento de Fuerza , Humanos , Entrenamiento de Fuerza/métodos , Masculino , Femenino , Adulto Joven , Músculo Esquelético/fisiología , Adulto , Temperatura Corporal/fisiología , Levantamiento de Peso/fisiología , Regulación de la Temperatura Corporal/fisiología , Fuerza Muscular/fisiología
17.
Int Urogynecol J ; 35(6): 1291-1298, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38758455

RESUMEN

INTRODUCTION AND HYPOTHESIS: Stress urinary incontinence (SUI) is defined as involuntary leakage of urine on physical effort and is prevalent among power- and weightlifters. However, there is scant knowledge on treatment options for this population. The aim of this pilot study was to evaluate the potential outcomes and feasibility of a pelvic floor muscle training (PFMT) program on SUI in nulliparous female power- and weightlifters. METHODS: This was a case-series study, including one weightlifter and two powerlifters aged 21-32 years. The participants conducted 12 weeks of PFMT at home, with weekly follow-up by a physiotherapist. Change in total score of the International Consensus of Incontinence Questionnaire Urinary Incontinence Short Form (ICIQ-UI-SF) was the primary outcome. Secondary outcome was perceived change assessed by the Patient Global Impression of Improvement (PGI-I) Scale and impact on sport participation. PFM strength, endurance, and resting pressure was measured using vaginal manometry. Feasibility was evaluated as adherence to training and self-efficacy (Self Efficacy Scale for Practicing Pelvic Floor Exercises). RESULTS: One athlete reduced their ICIQ-UI-SF score and experienced improvement in symptoms. One athlete reported no change, and one reported a worsening of symptoms. All three participants improved PFM strength and endurance, completed the testing, and 12 weeks of PFMT, but adherence varied between 40 and 80%. Participants reported a lack of time and energy and forgetting to perform the exercises, as reasons for low adherence. CONCLUSION: There were varying effects of a 12-week PFMT program on SUI in three strength athletes. The results can create the basis for a future randomized controlled trial.


Asunto(s)
Terapia por Ejercicio , Diafragma Pélvico , Incontinencia Urinaria de Esfuerzo , Levantamiento de Peso , Humanos , Femenino , Incontinencia Urinaria de Esfuerzo/terapia , Incontinencia Urinaria de Esfuerzo/fisiopatología , Proyectos Piloto , Diafragma Pélvico/fisiopatología , Adulto , Terapia por Ejercicio/métodos , Adulto Joven , Fuerza Muscular , Estudios de Factibilidad , Resultado del Tratamiento , Cooperación del Paciente
18.
J Strength Cond Res ; 38(8): 1401-1412, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38780903

RESUMEN

ABSTRACT: Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Boullosa, D, León-Prados, JA, Wernbom, M, and Pareja-Blanco, F. Acute responses to traditional and cluster-set squat training with and without blood flow restriction. J Strength Cond Res 38(8): 1401-1412, 2024-To compare the acute responses to different set configurations (cluster [CLU] vs. traditional [TRA]) under distinct blood flow conditions (free vs. restricted) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the set configuration (TRA: continuous repetitions; vs. CLU: 30 seconds of rest every 2 repetitions) and in the blood flow condition (FF: free-flow; vs. blood flow restriction [BFR]: 50% of arterial occlusion pressure). The relative intensity (60% 1RM), volume (3 sets of 8 repetitions), and resting time (2 minutes) were equated. Mean propulsive force (MPF), velocity (MPV) and power (MPP), and electromyography (EMG) parameters were recorded during each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ) height, maximal voluntary isometric contraction, in SQ, and movement velocity against the load that elicited a 1 m·s -1 velocity at baseline (V1-load) in SQ were assessed at pre- and post-exercise. The CLU protocols allowed a better maintenance of MPF, MPV, MPP, and EMG median frequency during the exercise compared to TRA (clu-time interaction, p < 0.05). The TRA protocols experienced greater impairments post-exercise in TMG- and EMG-derived variables (clu-time interaction, p < 0.05) and SQ and CMJ performance (clu-time interaction, p = 0.08 and p < 0.05, respectively), as well as higher blood lactate concentrations (clu-time interaction, p < 0.001) than CLU. Moreover, BFR displayed decreases in TMG variables (bfr-time interaction, p < 0.01), but BFR-CLU resulted in the greatest reduction in twitch contraction time ( p < 0.001). Cluster sets reduced fatigue during and after the training session and BFR exacerbated impairments in muscle mechanical properties; however, the combination of both could improve contraction speed after exercise.


Asunto(s)
Electromiografía , Fuerza Muscular , Músculo Esquelético , Entrenamiento de Fuerza , Humanos , Masculino , Entrenamiento de Fuerza/métodos , Adulto Joven , Músculo Esquelético/fisiología , Músculo Esquelético/irrigación sanguínea , Fuerza Muscular/fisiología , Adulto , Flujo Sanguíneo Regional/fisiología , Ácido Láctico/sangre , Levantamiento de Peso/fisiología
19.
Int J Sports Med ; 45(9): 690-697, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38729165

RESUMEN

This study investigated the effects of different resistance training (RT) volumes quantified by weekly sets at high intensity (load and effort) on dynamic strength adaptations and psychophysiological responses in trained individuals. Twenty-four athletes were randomly allocated to three groups that performed three (3 S, n=8), six (6 S, n=8), and nine (9 S, n=8) weekly sets, respectively, three times a week on the barbell back squat and bench press during an 8-week period. While all groups showcased strength gains (p<0.05), post hoc comparisons revealed that 6 S and 9 S elicited greater strength adaptations than 3 S in barbell back squat (p=0.027 and p=0.004, respectively) and bench press (p=0.001 and p=0.044, respectively). There were no differences between 6 S and 9 S conditions for back squat (p=0.999) and bench press (p=0.378). Although a time effect was observed for Session-RPE (p=0.014) and Total Quality Recovery scale (p=0.020), psychophysiological responses were similar among groups. Our findings suggest that performing six and nine weekly sets at high intensities led to greater strength gains compared to three weekly sets in strength-trained individuals, despite similar psychophysiological responses.


Asunto(s)
Adaptación Fisiológica , Fuerza Muscular , Entrenamiento de Fuerza , Humanos , Fuerza Muscular/fisiología , Entrenamiento de Fuerza/métodos , Masculino , Adulto Joven , Percepción/fisiología , Atletas , Levantamiento de Peso/fisiología , Adulto , Esfuerzo Físico/fisiología , Femenino
20.
Sci Rep ; 14(1): 9176, 2024 04 22.
Artículo en Inglés | MEDLINE | ID: mdl-38649771

RESUMEN

Back pain is one of the major global challenges and is one of the most prevalent musculoskeletal disorders occurring in 80% of people at least once in their lifetime. Therefore, the need to find appropriate treatment methods for this issue is very important. The objective is to examine the short-term and acute effects of a treatment session with dry needling, massage therapy, stretching exercises and Kinesio tape on pain, functional disability, position sense and range of motion in elite bodybuilders with non-specific chronic low back pain. The sample of this quasi-experimental study consisted of 48 bodybuilders with non-specific chronic low back pain (all male, mean age = 25.96 ± 2.18 years; mean weight = 74.45 ± 4.51 kg; mean height = 173.88 ± 3.74 cm; mean BMI = 24.60 ± 0.74 kg/m2) who randomly were placed in 4 dry needling, massage therapy, stretching exercises and Kinesio tape groups. The duration of each intervention was 30 min. The dependent variables in this study included the massage range of motion, position sense tests and visual pain scale that were taken separately from each subject in pretest, posttest (acute effect) and follow-up test (72 h after posttest; short-term effect). The results of a 4 (groups) × 3 (time) the mixed ANOVAs showed that pain in the short-term phase was significantly lower in the dry needling group than in the stretching and massage groups (P < 0.05). Also in the acute effect phase, the flexion range of motion was significantly lower in the dry needling group than in the massage group (P < 0.05). Furthermore, the two groups of stretching and massage exercises showed significantly greater range of motion (P < 0.05). Other comparisons were not significant (P > 0.05). The findings of the study showed that both massage and stretching treatment have higher acute effects, while dry needling treatment was more effective in follow up. On the other hand, these findings show that these treatment methods can have immediate and lasting positive effects in improving the performance in elite bodybuilders with non-specific chronic low back pain.


Asunto(s)
Dolor de la Región Lumbar , Rango del Movimiento Articular , Humanos , Dolor de la Región Lumbar/terapia , Dolor de la Región Lumbar/fisiopatología , Masculino , Adulto , Masaje/métodos , Dolor Crónico/terapia , Dolor Crónico/fisiopatología , Ejercicios de Estiramiento Muscular , Levantamiento de Peso , Resultado del Tratamiento , Dimensión del Dolor , Adulto Joven
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