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2.
Nutrients ; 16(13)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38999769

RESUMO

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.


Assuntos
Cafeína , Ratos Wistar , Levantamento de Peso , Animais , Cafeína/farmacologia , Cafeína/administração & dosagem , Masculino , Projetos Piloto , Ratos , Levantamento de Peso/fisiologia , Condicionamento Físico Animal/fisiologia , Substâncias para Melhoria do Desempenho/farmacologia , Substâncias para Melhoria do Desempenho/administração & dosagem
3.
Eur J Sport Sci ; 24(6): 732-739, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38874957

RESUMO

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.


Assuntos
Fadiga Mental , Treinamento Resistido , Humanos , Masculino , Feminino , Treinamento Resistido/métodos , Adulto Jovem , Adulto , Percepção/fisiologia , Esforço Físico/fisiologia , Teste de Stroop , Motivação , Levantamento de Peso/fisiologia , Levantamento de Peso/psicologia
4.
J Sports Med Phys Fitness ; 64(7): 640-649, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38916087

RESUMO

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.


Assuntos
Desempenho Atlético , Aprendizado de Máquina , Levantamento de Peso , Humanos , Desempenho Atlético/fisiologia , Masculino , Feminino , Levantamento de Peso/fisiologia , Modelos Lineares , Adulto Jovem , Adulto
5.
J Strength Cond Res ; 38(7): 1221-1230, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38900172

RESUMO

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.


Assuntos
Músculo Esquelético , Humanos , Masculino , Fenômenos Biomecânicos , Músculo Esquelético/fisiologia , Adulto , Adulto Jovem , Articulação do Tornozelo/fisiologia , Articulação do Quadril/fisiologia , Articulação do Joelho/fisiologia , Levantamento de Peso/fisiologia , Força Muscular/fisiologia , Treinamento Resistido/métodos , Equipamentos Esportivos
6.
J Strength Cond Res ; 38(7): 1213-1220, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38900171

RESUMO

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.


Assuntos
Ácido Láctico , Músculo Esquelético , Treinamento Resistido , Humanos , Masculino , Treinamento Resistido/métodos , Adulto Jovem , Feminino , Músculo Esquelético/fisiologia , Ácido Láctico/sangue , Mãos/fisiologia , Levantamento de Peso/fisiologia , Temperatura Baixa , Desempenho Atlético/fisiologia , Força Muscular/fisiologia , Esforço Físico/fisiologia , Eletromiografia , Adulto
7.
J Strength Cond Res ; 38(7): 1321-1325, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38900178

RESUMO

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.


Assuntos
Força Muscular , Treinamento Resistido , Levantamento de Peso , Humanos , Masculino , Treinamento Resistido/métodos , Adulto , Levantamento de Peso/fisiologia , Adulto Jovem , Força Muscular/fisiologia
8.
J Strength Cond Res ; 38(7): e341-e348, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38900182

RESUMO

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.


Assuntos
Militares , Humanos , Feminino , Masculino , Militares/psicologia , Adolescente , Adulto Jovem , Levantamento de Peso/fisiologia , Levantamento de Peso/psicologia , Lesões nas Costas/prevenção & controle , Coluna Vertebral/fisiologia , Adulto
9.
J Sport Rehabil ; 33(5): 333-339, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38734422

RESUMO

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.


Assuntos
Eletromiografia , Dor Lombar , Levantamento de Peso , Humanos , Dor Lombar/fisiopatologia , Masculino , Adulto , Levantamento de Peso/fisiologia , Adulto Jovem , Estudo de Prova de Conceito
10.
J Strength Cond Res ; 38(6): 1019-1024, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38781465

RESUMO

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.


Assuntos
Temperatura Alta , Músculo Esquelético , Treinamento Resistido , Humanos , Treinamento Resistido/métodos , Masculino , Feminino , Adulto Jovem , Músculo Esquelético/fisiologia , Adulto , Temperatura Corporal/fisiologia , Levantamento de Peso/fisiologia , Regulação da Temperatura Corporal/fisiologia , Força Muscular/fisiologia
11.
Int J Sports Physiol Perform ; 19(7): 685-695, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38772547

RESUMO

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.


Assuntos
Fadiga Muscular , Treinamento Resistido , Descanso , Humanos , Masculino , Feminino , Treinamento Resistido/métodos , Fadiga Muscular/fisiologia , Adulto Jovem , Fatores Sexuais , Descanso/fisiologia , Adulto , Percepção/fisiologia , Homeostase , Força Muscular/fisiologia , Contração Isométrica/fisiologia , Músculo Esquelético/fisiologia , Levantamento de Peso/fisiologia
12.
Int Urogynecol J ; 35(6): 1291-1298, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38758455

RESUMO

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.


Assuntos
Terapia por Exercício , Diafragma da Pelve , Incontinência Urinária por Estresse , Levantamento de Peso , Humanos , Feminino , Incontinência Urinária por Estresse/terapia , Incontinência Urinária por Estresse/fisiopatologia , Projetos Piloto , Diafragma da Pelve/fisiopatologia , Adulto , Terapia por Exercício/métodos , Adulto Jovem , Força Muscular , Estudos de Viabilidade , Resultado do Tratamento , Cooperação do Paciente
13.
J Electrocardiol ; 84: 95-99, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38579637

RESUMO

BACKGROUND: The control of the cardiovascular system depends on the autonomic nerve system. Chronic anabolic andorogenic steroids (AAS) use causes sympathovagal imbalance and increases sympathetic nerve activity. OBJECTIVE: The reduction in heart rate from the peak exercise rate following the end of the exercise stress test is known as the heart rate recovery index (HRRI). Several methods have been utilized to assess myocardial repolarization, such as QT interval (QT), corrected QT interval (QTc), and T-wave peak-to-end interval (Tp-e interval). Based on a growing number of data a higher Tp-e/QT ratio is linked to malignant ventricular arrhythmias, and an increased Tp-e interval may correlate with the transmural dispersion of repolarization. Our hypothesis is that the use of chronic AAS was decrease HRRI during maximal exercise and increased risk of cardiac arrhythmias and sudden cardiac death. METHODS: This study included 44 male bodybuilders, with an average age of 29.7 ± 8.14 years, divided into AAS abuse [AAS users (n = 21) and AAS nonuser (n = 23)]. RESULTS: The first (p = 0.001) and second minute (p = 0.001) HRRI of the subjects with AAS users were significantly lower than those of the control group. Additionally, HRRI after the third (p = 0.004) and fifth minutes (p = 0.007) of the recovery period were significantly lower in AAS group compared with the control group. Who used AAS had significantly higher QT, QTc, Tp-e, Tp-e/QT, and Tp-e/QTc values than non-users (all p = 0.001). CONCLUSIONS: Chronic AAS use has been shown to cause sympathetic dominance, which may be a pro arrhythmic state.


Assuntos
Eletrocardiografia , Frequência Cardíaca , Humanos , Masculino , Frequência Cardíaca/efeitos dos fármacos , Adulto , Levantamento de Peso , Anabolizantes/efeitos adversos , Arritmias Cardíacas/induzido quimicamente , Arritmias Cardíacas/fisiopatologia , Teste de Esforço , Androgênios/efeitos adversos , Androgênios/farmacologia , Esteróides Androgênicos Anabolizantes
14.
J Strength Cond Res ; 38(7): 1206-1212, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38595310

RESUMO

ABSTRACT: Hickmott, LM, Butcher, SJ, and Chilibeck, PD. A comparison of subjective estimations and objective velocities at quantifying proximity to failure for the bench press in resistance-trained men and women. J Strength Cond Res 38(7): 1206-1212, 2024-The purpose of this study was to compare the accuracy of quantifying repetitions in reserve (RIR) in the bench press among 18 men and 18 women between 2 conditions: (a) subjective estimations and (b) objective velocities. Subjects performed 4 sessions over 10 days: (a) 1 repetition maximum (1RM) test; (b) repetition-to-failure test at 80% of 1RM; (c) 3 sets to failure at 80% of 1RM; and (d) 3 sets to failure at 75, 80, and 85% of 1RM. During sessions 2, 3, and 4, subjects verbally stated their perceived 4 and 2 RIR intraset, whereas average concentric velocity was recorded on all repetitions. The dependent variable for the subjective estimations condition was the difference between the actual number of RIR and the subject's subjective estimated number of RIR at the verbally stated 4 and 2 RIR. The dependent variable for the objective velocities condition was the difference between the actual number of RIR and the number of RIR calculated from the subject's baseline individualized last repetition average concentric velocity-RIR profile. Significance was set at p ≤ 0.05. Sessions 3 and 4 had significant ( p < 0.001) condition × set and condition × load interactions, respectively, at both 4 and 2 RIR. Objective velocities were significantly more accurate than subjective estimations on set 1 and set 2 at both RIRs during session 3 and for 75 and 80% of 1RM at both RIRs during session 4. Objective velocities exhibit significantly greater accuracy than subjective estimations at quantifying RIR during initial sets and lower loads.


Assuntos
Treinamento Resistido , Levantamento de Peso , Humanos , Masculino , Treinamento Resistido/métodos , Feminino , Adulto Jovem , Adulto , Levantamento de Peso/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia
15.
J Pediatr Orthop ; 44(6): 373-378, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38606635

RESUMO

BACKGROUND: Increasing strength through weightlifting has become a core component of competitive sports training, recreational exercise programs, and school physical education classes. Although many health benefits exist, there is concern for injury, especially with improper supervision and accelerated progression of training loads. Though organizations have advocated safe training practices, trends in the national health burden of injuries, specifically fractures, associated with weightlifting in the adolescent population have not been investigated. METHODS: The National Electronic Injury Surveillance System database was queried between 2002 and 2021 for patients aged 11 to 21 years presenting to US Emergency Departments with weight lifting-related injuries. The narrative component of each case identified was analyzed to include only patients noted to be using weightlifting equipment or free weights at the time of injury. Estimates and analyses were performed with 95% CIs. RESULTS: Although there has been some variability in weight lifting-related injuries, the incidence remained roughly constant over the 20 years ( R2 =0.0364). 14,497 cases were identified, reflecting a national estimate of 540,986 total injuries and an annual estimate of 27,049 injuries. Most injuries occurred among 15-to-18-year olds (44.1%±1.6%) and 19-to-21-year olds (38.3%±2.0%). The most common injuries were sprain/strain (36.7%±1.3%), contusion/abrasion (15.7%±0.7%), and fracture (9.9%±0.3%). There were 53,813 estimated fractures, giving an annual incidence of 2,691 fractures. As a portion of all injuries, the number of fractures decreased significantly as patients got older, accounting for 26.8%±3.3% at age 11 and only 8.3%±0.9% at age 21 ( R2 =0.6626). Fingers (37.1%±1.8%) and toes (27.9%±1.4%) were the most fractured body parts. Overall, fractures mainly occurred either at school (25.3%±2.0%) or places of recreation (24.7%±2.2%). CONCLUSIONS: Despite the guidelines to improve safety, the national health burden of weight lifting-related injuries among adolescents has remained constant over the past 20 years. Given that most of the fractures occur in the distal extremities, such as toes and fingers, at school and places of recreation, there may be an opportunity to promote safer weightlifting practices and the development of weightlifting equipment with in-built safety mechanisms, especially at gyms and schools. LEVEL OF EVIDENCE: Level III-prognostic.


Assuntos
Fraturas Ósseas , Levantamento de Peso , Humanos , Adolescente , Levantamento de Peso/lesões , Levantamento de Peso/estatística & dados numéricos , Feminino , Masculino , Criança , Fraturas Ósseas/epidemiologia , Fraturas Ósseas/etiologia , Estados Unidos/epidemiologia , Adulto Jovem , Incidência , Traumatismos em Atletas/epidemiologia , Bases de Dados Factuais
16.
Int J Sports Physiol Perform ; 19(6): 593-599, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38608716

RESUMO

There has been an increase in the use of commercially available multi-ingredient preworkout supplements (MIPS); however, there are inconsistencies regarding the efficacy of MIPS in resistance-trained women. PURPOSE: To determine the effect of varying doses of MIPS compared with caffeine only (C) and a placebo (PL) on resistance-training performance in trained women. METHODS: Ten women (21.5 [2.3] y) completed 1-repetition-maximum tests at baseline for leg press and bench press. A within-group, double-blind, and randomized design was used to assign supplement drinks (ie, PL, C, MIPS half scoop [MIPS-H], and MIPS full scoop [MIPS-F]). Repetitions to failure were assessed at 75% and 80% to 85% of 1-repetition maximum for bench and leg press, respectively. Total performance volume was calculated as load × sets × repetitions for each session. Data were analyzed using a 1-way repeated-measures analysis of variance and reported as means and SDs. RESULTS: There were no differences in repetitions to failure for bench press (PL: 14.4 [3.2] repetitions, C: 14.4 [2.9] repetitions, MIPS-H: 14.2 [2.6] repetitions, MIPS-F: 15.1 [3.1] repetitions; P = .54) or leg press (PL: 13.9 [7.8] repetitions, C: 10.8 [5.9] repetitions, MIPS-H: 13.1 [7.1] repetitions, MIPS-F: 12.4 [10.7] repetitions; P = .44). Furthermore, there were no differences in total performance volume across supplements for bench press (PL: 911.2 [212.8] kg, C: 910.7 [205.5] kg, MIPS-H: 913.6 [249.3] kg, MIPS-F: 951.6 [289.6] kg; P = .39) or leg press (PL: 4318.4 [1633.6] kg, C: 3730.0 [1032.5] kg, MIPS-H: 4223.0 [1630.0] kg, MIPS-F: 4085.5 [2098.3] kg; P = .34). CONCLUSIONS: Overall, our findings suggest that caffeine and MIPS do not provide ergogenic benefits for resistance-trained women in delaying muscular failure.


Assuntos
Desempenho Atlético , Cafeína , Suplementos Nutricionais , Treinamento Resistido , Humanos , Feminino , Treinamento Resistido/métodos , Cafeína/administração & dosagem , Método Duplo-Cego , Adulto Jovem , Desempenho Atlético/fisiologia , Força Muscular/efeitos dos fármacos , Levantamento de Peso/fisiologia , Adulto , Substâncias para Melhoria do Desempenho/administração & dosagem
17.
Sci Rep ; 14(1): 9176, 2024 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-38649771

RESUMO

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.


Assuntos
Dor Lombar , Amplitude de Movimento Articular , Humanos , Dor Lombar/terapia , Dor Lombar/fisiopatologia , Masculino , Adulto , Massagem/métodos , Dor Crônica/terapia , Dor Crônica/fisiopatologia , Exercícios de Alongamento Muscular , Levantamento de Peso , Resultado do Tratamento , Medição da Dor , Adulto Jovem
18.
Nutrients ; 16(8)2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38674813

RESUMO

Despite increasing awareness of plant-based diets for health and athletic performance, athletes are cautioned that careful dietary monitoring is necessary. Whether commonly consumed plant-based diets are nutritionally adequate for maximal muscular hypertrophy remains unknown. This modeling study assessed the nutrient composition of completely plant-based diets scaled to the caloric demands of maximal muscle mass and strength development in adult male bodybuilders. To model calorie requirements, anthropometric data from bodybuilders were input into the Tinsley resting metabolic rate prediction equation, and an appropriate physical activity factor and calorie surplus were applied. Dietary data from a large cohort following completely plant-based diets were then scaled to meet these needs. Modeled intakes for nutrients of interest were calculated as 1.8 g/kg/day of protein and 2.75 g/meal of leucine, which surpass mean requirements for maximal increases in muscle mass and strength and muscle protein synthesis, respectively. Daily levels for all micronutrients, except vitamin D, also exceeded requirements. Saturated fat levels were aligned with dietary guidelines, although sodium levels exceeded recommended limits. Consumption of larger portions of commonplace plant-based diets, scaled to meet the energy demands of maximal accrual of muscle mass and strength, satisfied protein and leucine requirements without the need for additional planning.


Assuntos
Proteínas Alimentares , Ingestão de Energia , Leucina , Força Muscular , Músculo Esquelético , Treinamento Resistido , Humanos , Masculino , Proteínas Alimentares/administração & dosagem , Leucina/administração & dosagem , Força Muscular/fisiologia , Adulto , Músculo Esquelético/metabolismo , Necessidades Nutricionais , Dieta Vegetariana , Adulto Jovem , Hipertrofia , Levantamento de Peso/fisiologia , Dieta Baseada em Plantas
19.
J Strength Cond Res ; 38(5): e211-e218, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38662888

RESUMO

ABSTRACT: Corrêa Neto, VG, Silva, DdN, Palma, A, de Oliveira, F, Vingren, JL, Marchetti, PH, da Silva Novaes, J, and Monteiro, ER. Comparison between traditional and alternated resistance exercises on blood pressure, acute neuromuscular responses, and rating of perceived exertion in recreationally resistance-trained men. J Strength Cond Res 38(5): e211-e218, 2024-The purpose of this study was to compare the acute effects of traditional and alternated resistance exercises on acute neuromuscular responses (maximum repetition performance, fatigue index, and volume load), rating of perceived exertion (RPE), and blood pressure (BP) in resistance-trained men. Fifteen recreationally resistance-trained men (age: 26.40 ± 4.15 years; height: 173 ± 5 cm, and total body mass: 78.12 ± 13.06 kg) were recruited and performed all 3 experimental conditions in a randomized order: (a) control (CON), (b) traditional (TRT), and (c) alternated (ART). Both conditions (TRT and ART) consisted of 5 sets of bilateral bench press, articulated bench press, back squat, and Smith back squat exercises at 80% 1RM until concentric muscular failure. The total number of repetitions performed across sets in the bench press followed a similar pattern for TRT and ART, with significant reductions between sets 3, 4, and 5 compared with set 1 (p < 0.05). There was a significant difference for set 4 between conditions with a lower number of repetitions performed in the TRT. The volume load was significantly higher for ART when compared with TRT. TRT showed significant reductions in BP after 10-, 40-, and 60-minute postexercise and when compared with CON after 40- and 60-minute postexercise. However, the effect size illustrated large reductions in systolic BP during recovery in both methods. Thus, it is concluded that both methods reduced postexercise BP.


Assuntos
Pressão Sanguínea , Esforço Físico , Treinamento Resistido , Adulto , Humanos , Masculino , Adulto Jovem , Pressão Sanguínea/fisiologia , Fadiga Muscular/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Percepção/fisiologia , Esforço Físico/fisiologia , Treinamento Resistido/métodos , Levantamento de Peso/fisiologia
20.
J Strength Cond Res ; 38(5): 825-834, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38595263

RESUMO

ABSTRACT: Johansson, DG, Marchetti, PH, Stecyk, SD, and Flanagan, SP. A biomechanical comparison between the safety-squat bar and traditional barbell back squat. J Strength Cond Res 38(5): 825-834, 2024-The primary objectives for this investigation were to compare the kinematic and kinetic differences between performing a parallel back squat using a traditional barbell (TB) or a safety-squat bar (SSB). Fifteen healthy, recreationally trained male subjects (23 + 4 years of age) performed the back squat with a TB and an SSB at 85% of their respective 1 repetition maximum with each barbell while instrumented for biomechanical analysis. Standard inverse dynamics techniques were used to determine joint kinematic and kinetic measures. A 2 × 3 (exercise × joint) factorial analysis of variance with repeated measures was used to determine the kinetic and kinematic differences between the squats while using the different barbells. Fisher's least significant difference post hoc comparisons showed that the TB resulted in significantly greater maximum hip flexion angle (129.33 ± 11.8° vs. 122.11 ± 12.1°; p < 0.001; d = 1.80), peak hip net joint extensor torque (2.54 ± 0.4 Nm·kg -1 vs. 2.40 ± 0.4 Nm·kg -1 ; p = 0.001; d = 1.10), hip net extensor torque mechanical energy expenditure (MEE; 2.81 ± 0.5 Nm·kg -1 vs. 2.58 ± 0.6 Nm·kg -1 ; p = 0.002; d = 0.97), and ankle net joint plantar flexor torque MEE (0.32 ± 0.09 J·kg -1 vs. 0.28 ± 0.06 J·kg -1 ; p = 0.029; d = 0.63), while also lifting significantly (123.17 ± 20.8 kg vs. 117.17 ± 20.8 kg; p = 0.005; d = 0.858) more weight than the SSB. The SSB resulted in significantly higher maximum knee flexion angles (116.82 ± 5.8° vs. 115.65 ± 5.6°; p = 0.011; d = 0.75) than the TB, with no significant difference in kinetics at the knee. The TB may be preferred to the SSB for developing the hip extensors and lifting higher maximum loads. The SSB may be advantageous in situations where a more upright posture or a lower load is preferred while creating a similar demand for the knee joint.


Assuntos
Articulação do Joelho , Humanos , Masculino , Fenômenos Biomecânicos , Adulto Jovem , Adulto , Articulação do Joelho/fisiologia , Articulação do Quadril/fisiologia , Torque , Levantamento de Peso/fisiologia , Músculo Esquelético/fisiologia , Articulação do Tornozelo/fisiologia , Treinamento Resistido/métodos , Amplitude de Movimento Articular/fisiologia
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