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1.
Sci Rep ; 14(1): 7744, 2024 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-38565633

RESUMO

This study aimed to determine the effects of resistance training combined with a probiotic supplement enriched with vitamin D and leucine on sestrin2, oxidative stress, antioxidant defense, and mitophagy markers in aged Wistar rats. Thirty-five male rats were randomly assigned to two age groups (old with 18-24 months of age and young with 8-12 weeks of age) and then divided into five groups, including (1) old control (OC: n = 5 + 2 for reserve in all groups), (2) young control (YC: n = 5), (3) old resistance training (OR: n = 5), (4) old resistance training plus supplement (ORS: n = 5), and old supplement group (OS: n = 5). Training groups performed ladder climbing resistance training 3 times per week for 8 weeks. Training intensity was inserted progressively, with values equal to 65, 75, and 85, determining rats' maximal carrying load capacity. Each animal made 5 to 8 climbs in each training session, and the time of each climb was between 12 and 15 s, although the time was not the subject of the evaluation, and the climbing pattern was different in the animals. Old resistance plus supplement and old supplement groups received 1 ml of supplement 5 times per week by oral gavage in addition to standard feeding, 1 to 2 h post training sessions. Forty-eight hours after the end of the training program, 3 ml of blood samples were taken, and all rats were then sacrificed to achieve muscle samples. After 8 weeks of training, total antioxidant capacity and superoxide dismutase activity levels increased in both interventions. A synergistic effect of supplement with resistance training was observed for total antioxidant capacity, superoxide dismutase, and PTEN-induced kinase 1. Sestrin 2 decreased in intervention groups. These results suggest that resistance training plus supplement can boost antioxidant defense and mitophagy while potentially decreasing muscle strength loss.


Assuntos
Condicionamento Físico Animal , Probióticos , Treinamento de Força , Humanos , Idoso , Ratos , Masculino , Animais , Lactente , Pré-Escolar , Ratos Wistar , Antioxidantes/metabolismo , Treinamento de Força/métodos , Mitofagia , Condicionamento Físico Animal/fisiologia , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Músculo Esquelético/metabolismo
2.
BMJ Open ; 14(4): e082192, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38643006

RESUMO

INTRODUCTION: With increasing life expectancy of older adult population, maintaining independence and well-being in later years is of paramount importance. This study aims to investigate the impact of three distinct interventions: cognitive training, resistance training and a combination of both, compared with an inactive control group, on cognitive performance, mobility and quality of life in adults aged ≥65 years. METHODS AND ANALYSIS: This trial will investigate healthy older adults aged ≥65 years living independently without cognitive impairments. Participants will be randomly assigned to one of four groups: (1) cognitive training, (2) resistance training, (3) combined cognitive and resistance training, and (4) control group (n=136 participants with 34 participants per group). The interventions will be conducted over 12 weeks. The cognitive training group will receive group-based activities for 45-60 min two times a week. The resistance training group exercises will target six muscle groups and the combined group will integrate cognitive tasks into the resistance training sessions. Primary outcomes are: Short Physical Performance Battery, Sit-to-Stand Test, Montreal Cognitive Assessment, Trail Making Test and Stroop Test combined with gait on a treadmill (dual task). Life satisfaction will be measured by the Satisfaction With Life Scale. Secondary outcomes encompass hand grip strength and the Functional Independence Measure. ETHICS AND DISSEMINATION: Ethical approval was provided by the local Ethics Committee at the University of Hamburg (no. 2023_009). Informed consent will be obtained from all study participants. The results of the study will be distributed for review and discussion in academic journals and conferences. TRIAL REGISTRATION NUMBER: DRKS00032587.


Assuntos
Treinamento de Força , Humanos , Idoso , Treinamento de Força/métodos , Força da Mão , Qualidade de Vida , Marcha , Cognição , Terapia por Exercício/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
Scand J Med Sci Sports ; 34(3): e14608, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38515303

RESUMO

PURPOSE: The aim of this study was to determine whether a 9-week resistance training program based on high load (HL) versus low load combined with blood flow restriction (LL-BFR) induced a similar (i) distribution of muscle hypertrophy among hamstring heads (semimembranosus, SM; semitendinosus, ST; and biceps femoris long head, BF) and (ii) magnitude of tendon hypertrophy of ST, using a parallel randomized controlled trial. METHODS: A total of 45 participants were randomly allocated to one of three groups: HL, LL-BFR, and control (CON). Both HL and LL-BFR performed a 9-week resistance training program composed of seated leg curl and stiff-leg deadlift exercises. Freehand 3D ultrasound was used to assess the changes in muscle and tendon volume. RESULTS: The increase in ST volume was greater in HL (26.5 ± 25.5%) compared to CON (p = 0.004). No difference was found between CON and LL-BFR for the ST muscle volume (p = 0.627). The change in SM muscle volume was greater for LL-BFR (21.6 ± 27.8%) compared to CON (p = 0.025). No difference was found between HL and CON for the SM muscle volume (p = 0.178).There was no change in BF muscle volume in LL-BFR (14.0 ± 16.5%; p = 0.436) compared to CON group. No difference was found between HL and CON for the BF muscle volume (p = 1.0). Regarding ST tendon volume, we did not report an effect of training regimens (p = 0.411). CONCLUSION: These results provide evidence that the HL program induced a selective hypertrophy of the ST while LL-BFR induced hypertrophy of SM. The magnitude of the selective hypertrophy observed within each group varied greatly between individuals. This finding suggests that it is very difficult to early determine the location of the hypertrophy among a muscle group.


Assuntos
Músculos Isquiossurais , Treinamento de Força , Humanos , Músculos Isquiossurais/diagnóstico por imagem , Força Muscular/fisiologia , Hipertrofia , Tendões , Treinamento de Força/métodos , Fluxo Sanguíneo Regional/fisiologia , Músculo Esquelético/fisiologia
4.
Sensors (Basel) ; 24(6)2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38544173

RESUMO

Incorrect limb position while lifting heavy weights might compromise athlete success during weightlifting performance, similar to the way that it increases the risk of muscle injuries during resistance exercises, regardless of the individual's level of experience. However, practitioners might not have the necessary background knowledge for self-supervision of limb position and adjustment of the lifting position when improper movement occurs. Therefore, the computerized analysis of movement patterns might assist people in detecting changes in limb position during exercises with different loads or enhance the analysis of an observer with expertise in weightlifting exercises. In this study, hidden Markov models (HMMs) were employed to automate the detection of joint position and barbell trajectory during back squat exercises. Ten volunteers performed three lift movements each with a 0, 50, and 75% load based on body weight. A smartphone was used to record the movements in the sagittal plane, providing information for the analysis of variance and identifying significant position changes by video analysis (p < 0.05). Data from individuals performing the same movements with no added weight load were used to train the HMMs to identify changes in the pattern. A comparison of HMMs and human experts revealed between 40% and 90% agreement, indicating the reliability of HMMs for identifying changes in the control of movements with added weight load. In addition, the results highlighted that HMMs can detect changes imperceptible to the human visual analysis.


Assuntos
Treinamento de Força , Humanos , Reprodutibilidade dos Testes , Treinamento de Força/métodos , Levantamento de Peso/fisiologia , Postura , Extremidades , Movimento
5.
Sensors (Basel) ; 24(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38544213

RESUMO

Movement control can be an indicator of how challenging a task is for the athlete, and can provide useful information to improve training efficiency and prevent injuries. This study was carried out to determine whether inertial measurement units (IMU) can provide reliable information on motion variability during strength exercises, focusing on the squat. Sixty-six healthy, strength-trained young adults completed a two-day protocol, where the variability in the squat movement was analyzed at two different loads (30% and 70% of one repetition maximum) using inertial measurement units and a force platform. The time series from IMUs and force platforms were analyzed using linear (standard deviation) and non-linear (detrended fluctuation analysis, sample entropy and fuzzy entropy) measures. Reliability was analyzed for both IMU and force platform using the intraclass correlation coefficient and the standard error of measurement. Standard deviation, detrended fluctuation analysis, sample entropy, and fuzzy entropy from the IMUs time series showed moderate to good reliability values (ICC: 0.50-0.85) and an acceptable error. The study concludes that IMUs are reliable tools for analyzing movement variability in strength exercises, providing accessible options for performance monitoring and training optimization. These findings have implications for the design of more effective strength training programs, emphasizing the importance of movement control in enhancing athletic performance and reducing injury risks.


Assuntos
Treinamento de Força , Adulto Jovem , Humanos , Treinamento de Força/métodos , Reprodutibilidade dos Testes , Fenômenos Biomecânicos , Postura , Exercício Físico
6.
BMC Public Health ; 24(1): 798, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38481173

RESUMO

BACKGROUND: The COVID-19 pandemic has had a significant impact on individual health and fitness routines globally. Resistance training, in particular, has become increasingly popular among men and women looking to maintain or improve their physical fitness during the pandemic. However, using Anabolic Steroids (AS) for performance enhancement in resistance training has known adverse effects. Thus, this study aimed to explore the prevalence of AS use among men and women resistance training practitioners after the COVID-19 pandemic. METHODS: A cross-sectional survey was conducted among 3,603 resistance training practitioners (1,855 men and 1,748 women) in various geographical locations impacted by COVID-19. The participants were asked to complete self-administered questionnaires, which included questions regarding demographic information, training habits, and current or prior usage of AS. The data were analyzed using SPSS statistical software and the chi-square method, with a significance level of (P < 0.05). RESULTS: A total of 3603 men and women resistance training practitioners completed the survey. In the study, 53.05% of men and 41.99% of women used anabolic and androgenic steroids. Of those men who used steroids, 29.47% used Testosterone, while 31.20% of women used Winstrol. Additionally, 50.30% of men used steroids via injection, while 49.05% of women used them orally. According to the study, 49.99% of the participants had 6 to 12 months of experience with resistance training, and 64.25% of them underwent three training sessions per week. The analysis using the χ2 test did not reveal any significant difference between men and women in terms of duration of bodybuilding, frequency per week, and engagement in other activities. CONCLUSION: This study shows that a significant proportion of men and women resistance training practitioners used AS, particularly among young adults with limited training experience. Thus, there is a need for targeted education and awareness campaigns to address the hazards of AS use and promote healthy training habits during the COVID-19 pandemic.


Assuntos
Anabolizantes , COVID-19 , Treinamento de Força , Masculino , Adulto Jovem , Humanos , Feminino , Esteróides Androgênicos Anabolizantes , Pandemias , Treinamento de Força/métodos , Prevalência , Estudos Transversais , Anabolizantes/uso terapêutico , Congêneres da Testosterona , Esteroides
7.
PLoS One ; 19(3): e0298859, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38512981

RESUMO

The aim of this study was to investigate the reliability and validity of an affordable wireless force sensor in measuring mean and peak forces during resistance training.A Suiff Pro wireless force sensor (Suiff, Spain) and a MuscleLab force platform (Ergotest, Norway) were used concurrently to assess tensile load and the ground reaction force resulting from an upright row exercise. Thirteen participants (28.2 ± 5.7 years, 76.2 ± 9.6 kg, 178.2 ± 9.2 cm) performed the exercise under three velocity conditions and isometrically. Each condition involved three sets of exercise. Mean (Fmean) and peak (Fpeak) force values from both sensors were collected and compared.Suiff Pro exhibited excellent reliability for Fmean and Fpeak (ICCs = 0.99). When compared to the criterion measures, Suiff Pro showed trivial standardized bias for Fmean (Mean = 0.00 [CI 95% = 0.00 to 0.01]) and Fpeak (-0.02 [-0.04 to 0.00]). The standardized typical error was also trivial for Fmean (0.03 [0.02 to 0.03]) and Fpeak (0.07 [0.05 to 0.09]). Correlations with the MuscleLab force platform were nearly perfect: Fmean (0.97 [0.94 to 0.98]; p<0.001); Fpeak (0.96 [0.92 to 0.97]; p<0.001).The findings demonstrate that the Suiff Pro sensor is reliable and valid device for measuring force during isometric and dynamic resistance training exercises. Therefore, practitioners can confidently use this device to monitor kinematic variables of resistance training exercises and to obtain real-time augmented feedback during a training session.


Assuntos
Aplicativos Móveis , Treinamento de Força , Humanos , Treinamento de Força/métodos , Reprodutibilidade dos Testes , Exercício Físico , Fenômenos Biomecânicos , Força Muscular
8.
J Strength Cond Res ; 38(4): 787-790, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38513182

RESUMO

ABSTRACT: Nunes, JP, Blazevich, AJ, Schoenfeld, BJ, Kassiano, W, Costa, BDV, Ribeiro, AS, Nakamura, M, Nosaka, K, and Cyrino, ES. Determining changes in muscle size and architecture after exercise training: One site does not fit all. J Strength Cond Res 38(4): 787-790, 2024-Different methods can be used to assess muscle hypertrophy, but the effects of training on regional changes in muscle size can be detected only using direct muscle measurements such as muscle thickness, cross-sectional area, or volume. Importantly, muscle size increases vary across regions within and between muscles after resistance training programs (i.e., heterogeneous, or nonuniform, muscle hypertrophy). Muscle architectural changes, including fascicle length and pennation angle, after resistance and stretch training programs are also region-specific. In this paper, we show that the literature indicates that a single-site measure of muscle shape does not properly capture the effects achieved after exercise training interventions and that conclusions concerning the magnitude of muscle adaptations can vary substantially depending on the muscle site to be examined. Thus, we propose that measurements of muscle size and architecture should be completed at multiple sites across regions between the agonist muscles within a muscle group and along the length of the muscles to provide an adequate picture of training effects.


Assuntos
Músculo Esquelético , Treinamento de Força , Humanos , Músculo Esquelético/fisiologia , Força Muscular/fisiologia , Músculo Quadríceps/fisiologia , Exercício Físico/fisiologia , Treinamento de Força/métodos , Hipertrofia
9.
J Strength Cond Res ; 38(4): e160-e173, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38513184

RESUMO

ABSTRACT: Weldon, A, Cloak, R, Kirk, C, Ruddock, A, Langan-Evans, C, Detanico, D, Loturco, I, and Kons, R. Strength and conditioning (S&C) practices of judo athletes and S&C coaches: A survey-based investigation. J Strength Cond Res 38(4): e160-e173, 2024-The benefits of strength and conditioning (S&C) for improving judo performance and reducing injuries have been widely studied. However, the S&C practices used and perspectives held by those delivering S&C have yet to be elucidated. Therefore, this study investigated the S&C practices and perspectives of judokas and S&C coaches working within judo. Forty-two judokas and 9 S&C coaches completed an online survey comprising 6 sections: (a) written informed consent; (b) background information; (c) education, qualifications, and prescription; (d) views on S&C; (e) exercise selection; and (f) issues and improvements. Frequency analysis was used to report responses to fixed-response questions and thematic analysis for open-ended questions. Results indicated that S&C coaches were primarily responsible for delivering S&C programs (60%), and S&C information was predominantly sourced from S&C coaches (43%). Strength and conditioning was deemed very important for randori (78-88%), overall judo performance (67-79%), and judo fitness (62-78%). Similarly, S&C was considered very important for the development of speed and power (76-89%), strength (71-89%), and injury reduction (69-78%). Novel findings were also observed, such as integrating judo-specific training within S&C practice, which may be partly explained by more S&C coaches holding judo belts (67%) than S&C qualifications (11%). This study supports practitioners delivering S&C in judo by offering a base of information to critique or align with their existing S&C practices and perspectives. Furthermore, our results may help identify potential gaps between methods used, proposed guidelines, and actual practice, facilitating the development of research and education resources tailored to the current climate.


Assuntos
Artes Marciais , Treinamento de Força , Humanos , Educação Física e Treinamento , Treinamento de Força/métodos , Inquéritos e Questionários , Atletas
10.
PLoS One ; 19(3): e0298517, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38517872

RESUMO

Resisted sprint and assisted sprint are the two main types of training methods used by athletes in sprint training, so optimizing resisted sprint training and assisted sprint training process is beneficial for improving athletes' sprint performance. Kinematics is the most intuitive parameter that reflects the quality of training during running process, and it is particularly important to analyze the gait of athletes during resisted and assisted sprint process. Therefore, this paper investigates the effects of resisted and assisted sprint on the sprint kinematics of sprinters in the first 30 meters to demonstrate the targeted effects of resisted and assisted sprint training. The experimental results show that compared to the unloaded running, male collegiate sprinters increase their total step count, decrease their step length, increase their step time, increase their contact time, whereas have almost no change in the flight time when performing the 30-m resisted sprint. Male collegiate sprinters decrease their total step count, increase their step length, increase their step time, decrease their contact time and increase their flight time, when performing the 30-m assisted sprint. In addition, it is found that resisted sprint training is beneficial for improving the athletes' power and explosiveness during the acceleration phase, thereby improving acceleration ability. However, prolonged and frequent resisted sprint training may reduce the step length and step frequency of athletes. Assisted sprint training is beneficial for shortening the contact time of athletes, improving their step length and flight time, and enabling them to overspeed, thereby increasing their maximum speed ability.


Assuntos
Desempenho Atlético , Treinamento de Força , Corrida , Humanos , Masculino , Fenômenos Biomecânicos , Atletas , Marcha , Treinamento de Força/métodos
11.
J Appl Physiol (1985) ; 136(4): 889-900, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38450425

RESUMO

Resistance training at longer muscle lengths induces greater muscle hypertrophy and different neuromuscular functional adaptations than training at shorter muscle lengths. However, the acute time course of recovery of neuromuscular characteristics after resistance exercise at shorter and longer muscle lengths in the quadriceps has never been described. Eight healthy young participants (4 M, 4 F) were randomly assigned to perform four sets of eight maximal isometric contractions at shorter (SL; 50° knee flexion) or longer (LL; 90° knee flexion) muscle lengths in a crossover fashion. During exercise, peak torque (PT), muscle activity [electromyogram (EMG)], and internal muscle forces were assessed. PT and EMG at shorter (PT50, EMG50) and longer (PT90, EMG90) muscle lengths, creatine kinase (CK), and muscle soreness were measured at baseline, immediately after exercise (Post), after 24 h (24 h), and after 48 h (48 h). During exercise, EMG (P = 0.002) and internal muscle forces (P = 0.017) were greater in LL than in SL. During recovery, there was a main effect of exercise angle, with PT50 (P = 0.002), PT90 (P = 0.016), and EMG50 (P = 0.002) all significantly reduced to a greater degree in LL compared with SL. CK and muscle soreness increased after resistance exercise, but there were no differences between SL and LL. The present results suggest that if the preceding isometric resistance exercise is performed at longer muscle lengths, function and muscle activity at shorter and longer muscle lengths are inhibited to a larger degree in the subsequent recovery period. This information can be used by practitioners to manipulate exercise prescription.NEW & NOTEWORTHY Despite the established long-term benefits of training at longer muscle lengths for muscle size and strength, acutely performing resistance exercise at longer muscle lengths may require a longer time course of neuromuscular recovery compared with performing resistance exercises at shorter muscle lengths. Furthermore, there appear to be different joint angle-specific recovery profiles, depending on the muscle length of the preceding exercise.


Assuntos
Músculo Esquelético , Treinamento de Força , Humanos , Músculo Esquelético/fisiologia , Treinamento de Força/métodos , Mialgia , Eletromiografia , Músculo Quadríceps , Contração Isométrica/fisiologia , Creatina Quinase , Torque
12.
Physiol Meas ; 45(4)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38507792

RESUMO

Objective. Surface mechanomyography (sMMG) can measure oscillations of the activated muscle fibers in three axes (i.e.X,Y, andZ-axes) and has been used to describe motor unit activation patterns (X-axis). The application of blood flow restriction (BFR) is common in exercise studies, but the cuff may restrict muscle fiber oscillations. Therefore, the purpose of this investigation was to examine the acute effects of submaximal, fatiguing exercise with and without BFR on sMMG amplitude in theX,Y, andZ-axes among female participants.Approach. Sixteen females (21 ± 1 years) performed two separate exercise bouts to volitional exhaustion that consisted of unilateral, submaximal (50% maximal voluntary isometric contraction [MVIC]) intermittent, isometric, leg extensions with and without BFR. sMMG was recorded and examined across percent time to exhaustion (%TTE) in 20% increments. Separate 2-way repeated measures ANOVA models were constructed: (condition [BFR, non-BFR]) × (time [20, 40, 60, 80, and 100% TTE]) to examine absolute (m·s-2) and normalized (% of pretest MVIC) sMMG amplitude in theX-(sMMG-X),Y-(sMMG-Y), andZ-(sMMG-Z) axes.Main results. The absolute sMMG-X amplitude responses were attenuated with the application of BFR (mean ± SD = 0.236 ± 0.138 m·s-2) relative to non-BFR (0.366 ± 0.199 m·s-2, collapsed across time) and for sMMG-Y amplitude at 60%-100% of TTE (BFR range = 0.213-0.232 m·s-2versus non-BFR = 0.313-0.445 m·s-2). Normalizing sMMG to pretest MVIC removed most, but not all the attenuation which was still evident for sMMG-Y amplitude at 100% of TTE between BFR (72.9 ± 47.2%) and non-BFR (98.9 ± 53.1%). Interestingly, sMMG-Z amplitude was not affected by the application of BFR and progressively decreased across %TTE (0.332 ± 0.167 m·s-2to 0.219 ± 0.104 m·s-2, collapsed across condition.)Significance. The application of BFR attenuated sMMG-X and sMMG-Y amplitude, although normalizing sMMG removed most of this attenuation. Unlike theXandY-axes, sMMG-Z amplitude was not affected by BFR and progressively decreased across each exercise bout potentially tracking the development of muscle fatigue.


Assuntos
Fadiga Muscular , Treinamento de Força , Humanos , Feminino , Fadiga Muscular/fisiologia , Exercício Físico/fisiologia , Contração Isométrica/fisiologia , Fluxo Sanguíneo Regional , Modalidades de Fisioterapia , Músculo Esquelético/fisiologia , Eletromiografia , Treinamento de Força/métodos
13.
PeerJ ; 12: e17079, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38525282

RESUMO

This study aimed to compare the effects of 8 weeks (24 sessions) between flywheel complex training with eccentric overload and traditional complex training of well-trained volleyball players on muscle adaptation, including hypertrophy, strength, and power variables. Fourteen athletes were recruited and randomly divided into the flywheel complex training with an eccentric-overload group (FCTEO, n = 7) and the control group (the traditional complex training group, TCT, n = 7). Participants performed half-squats using a flywheel device or Smith machine and drop jumps, with three sets of eight repetitions and three sets of 12 repetitions, respectively. The variables assessed included the muscle thickness at the proximal, mid, and distal sections of the quadriceps femoris, maximal half-squats strength (1RM-SS), squat jump (SJ), countermovement jump (CMJ), and three-step approach jump (AJ). In addition, a two-way repeated ANOVA analysis was used to find differences between the two groups and between the two testing times (pre-test vs. post-test). The indicators of the FCTEO group showed a significantly better improvement (p < 0.05) in CMJ (height: ES = 0.648, peak power: ES = 0.750), AJ (height: ES = 0.537, peak power: ES = 0.441), 1RM-SS (ES = 0.671) compared to the TCT group and the muscle thicknes at the mid of the quadriceps femoris (ES = 0.504) after FCTEO training. Since volleyball requires lower limb strength and explosive effort during repeated jumps and spiking, these results suggest that FCTEO affects muscular adaptation in a way that improves performance in well-trained female volleyball players.


Assuntos
Treinamento de Força , Voleibol , Feminino , Humanos , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Músculo Quadríceps , Treinamento de Força/métodos , Voleibol/fisiologia
14.
PeerJ ; 12: e16865, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38313010

RESUMO

Background: The barbell squat is an exercise used to strengthen the lower limbs, with implications for both performance in sports and improving movement during everyday tasks. Although the exercise is being trained across a variety of repetition ranges, the technical requirements may vary, affecting appropriate repetition range for specific training goals. Methods: A randomised within-subject design was used to compare kinematics and surface electromyography (EMG) in the lower extremities during different concentric phases (pre-, sticking- and post-sticking region) of the last repetition when performing squats at different repetition maximums (RMs). Thirteen strength-trained men (age: 23.6 ± 1.9 years; height: 181.1 ± 6.5 cm; body mass: 82.2 kg, 1RM: 122.8 ± 16.2, relative strength: 1.5 ± 0.2 x body mass in external load) performed a 1, 3, 6, and 10RM squat, in a randomised order. Results: The main findings were that barbell-, ankle-, knee- and hip kinematics were similar across different repetition ranges, except for a smaller trunk lean at 1RM in the pre-sticking region compared to other repetitions and in the sticking region compared to 10RM (p ≤ 0.04). Furthermore, 1RM revealed significantly higher EMG amplitude in the vastus lateralis, gastrocnemius and soleus in the sticking and post-sticking regions when compared to 10RM. It was concluded that 10RM may locally fatigue the vastus lateralis and plantar flexors, explaining the lower EMG amplitude. The observed differences indicate that requirements vary for completing the final repetition of the 10RM compared to the 1RM, an important aspect to consider in training to enhance 1RM strength.


Assuntos
Treinamento de Força , Levantamento de Peso , Adulto , Humanos , Masculino , Adulto Jovem , Fenômenos Biomecânicos , Eletromiografia/métodos , Músculo Esquelético , Treinamento de Força/métodos
15.
J Sports Sci ; 42(1): 73-84, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38412241

RESUMO

We sought to determine the effects of blood flow restriction (BFR) on exercise-induced hypoalgesia, specifically using low-load (LL) resistance exercise (30% 1RM) protocols that accounted for each individual's local muscular endurance capabilities. Forty-four participants completed four conditions: (1) 70% of maximal BFR repetitions with blood flow restriction (LL+BFR exercise); (2) 70% maximal BFR repetitions without LL+BFR (LL exercise); (3) 70% maximal free flow repetitions (LL+EFFORT exercise); (4) time-matched, non-exercise control (CON). Pressure pain threshold (PPT) was measured before and after exercise. Ischaemic pain threshold and tolerance was assessed only at post. The change in upper body PPT was greater for LL+BFR exercise compared to LL exercise [difference of 0.15 (0.35) kg/cm2], LL+EFFORT exercise [difference of 0.23 (0.45) kg/cm2], and the CON condition. The change in lower body PPT was greater for LL+BFR exercise compared to LL exercise [difference of 0.40 (0.55) kg/cm2], LL+EFFORT exercise [difference of 0.36 (0.62) kg/cm2], and the CON condition. Ischaemic pain thresholds and tolerances did not change. Submaximal exercise with BFR resulted in systemic increases in PPT but had no influence on ischaemic pain sensitivity. This effect is likely unique to BFR as we did not see changes in the effort matched free flow condition.


Assuntos
Limiar da Dor , Treinamento de Força , Humanos , Fluxo Sanguíneo Regional/fisiologia , Hemodinâmica , Dor , Exercício Físico/fisiologia , Treinamento de Força/métodos , Músculo Esquelético/fisiologia
16.
Physiol Rep ; 12(5): e15955, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38418370

RESUMO

Establishing a relationship between repetitions left in reserve and the mean absolute velocity (RIR-velocity relationship) during resistance training (RT) could allow for objective monitoring, prescription, and real-time adjustment of the training load and set-volume. Therefore, we examined the goodness of fit and prediction accuracy of general and individual RIR-velocity relationships in the free-weight back squat exercise. The effects of sex, training status and history, as well as personality traits, on the goodness of fit and the accuracy of these relationships were also investigated. Forty-six resistance-trained people (15 females and 31 males) performed a one-repetition maximum (1RM) test, and two repetitions to failure (RTF) tests 72 h apart. We found greater goodness of fit of individual RIR-velocity relationships compared to general RIR-velocity relationships. Individual, but not general RIR-velocity relationships established in the first testing session yielded acceptable prediction accuracy of RIR (mean error <2 repetitions) in the subsequent testing session, regardless of the load used. Similar results were obtained when both general and individual RIR-velocity relationships were averaged across the loads, suggesting that a single RIR-velocity relationship covering a range of loads can be used instead of traditional RT methods, potentially allowing for better fatigue management and more efficient adaptation.


Assuntos
Músculo Esquelético , Treinamento de Força , Masculino , Feminino , Humanos , Treinamento de Força/métodos , Força Muscular , Fadiga/terapia , Prescrições
17.
BMC Musculoskelet Disord ; 25(1): 138, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38350917

RESUMO

BACKGROUND: Hip osteoarthritis (OA) is a leading cause of chronic pain and disability worldwide. Self-management is vital with education, exercise and weight loss core recommended treatments. However, evidence-practice gaps exist, and service models that increase patient accessibility to clinicians who can support lifestyle management are needed. The primary aim of this study is to determine the effectiveness of a telehealth-delivered clinician-supported exercise and weight loss program (Better Hip) on the primary outcomes of hip pain on walking and physical function at 6 months, compared with an information-only control for people with hip OA. METHODS: A two-arm, parallel-design, superiority pragmatic randomised controlled trial. 212 members from a health insurance fund aged 45 years and over, with painful hip OA will be recruited. Participants will be randomly allocated to receive: i) Better Hip; or ii) web-based information only (control). Participants randomised to the Better Hip program will have six videoconferencing physiotherapist consultations for education about OA, prescription of individualised home-based strengthening and physical activity programs, behaviour change support, and facilitation of other self-management strategies. Those with a body mass index > 27 kg/m2, aged < 80 years and no specific health conditions, will also be offered six videoconferencing dietitian consultations to undertake a weight loss program. Participants in the control group will be provided with similar educational information about managing hip OA via a custom website. All participants will be reassessed at 6 and 12 months. Primary outcomes are hip pain on walking and physical function. Secondary outcomes include measures of pain; hip function; weight; health-related quality of life; physical activity levels; global change in hip problem; willingness to undergo hip replacement surgery; rates of hip replacement; and use of oral pain medications. A health economic evaluation at 12 months will be conducted and reported separately. DISCUSSION: Findings will determine whether a telehealth-delivered clinician-supported lifestyle management program including education, exercise/physical activity and, for those with overweight or obesity, weight loss, is more effective than information only in people with hip OA. Results will inform the implementation of such programs to increase access to core recommended treatments. TRIAL REGISTRATION: Australia New Zealand Clinical Trials Registry (ACTRN12622000461796).


Assuntos
Osteoartrite do Quadril , Osteoartrite do Joelho , Treinamento de Força , Telemedicina , Programas de Redução de Peso , Humanos , Osteoartrite do Quadril/diagnóstico , Osteoartrite do Quadril/terapia , Osteoartrite do Quadril/complicações , Osteoartrite do Joelho/diagnóstico , Osteoartrite do Joelho/terapia , Osteoartrite do Joelho/complicações , Qualidade de Vida , Resultado do Tratamento , Dor , Artralgia/etiologia , Terapia por Exercício/métodos , Treinamento de Força/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto
18.
BMC Geriatr ; 24(1): 173, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38373934

RESUMO

BACKGROUND: Transient progressive weakness and disability of lower limb during the early stage after TKR will increase the risk of fall, but the superior postoperative strength training mode have not been elucidated for functional restoration. This study aimed to compare whether the isokinetic lower limb training is superior to either isotonic or home isometric exercise during early stage after TKR in older people. METHODS: A total of 43 recruited old participants (mean age, 68.40 years old) receiving TKR were divided randomly based on the different four-week training modes into three groups including isokinetic, isotonic, and home isometric exercise (control group). The primary outcome was set as functional performance in terms of Timed Up and Go (TUG) test and the secondary outcomes include the peak torque of knee at 60 and 120 degree/ second, Short-Form 36 Health Survey (SF-36), and Western Ontario and McMaster Universities Arthritis index (WOMAC). RESULTS: All of the peak torque measurements of the knee improved significantly in both the isokinetic and the isotonic group, but not in the control group. Although isotonic training resulted in more strength gains, a significant enhancement in TUG test was observed in the isokinetic group only (p = 0.003). However, there were no significantly improvement of TUG test after training in other two groups. SF-36 and WOMAC improved after training in all three groups, with no significant difference in the degree of improvement between groups. CONCLUSION: Isokinetic training for 4 weeks following TKR effectively improved all the outcome parameters in this study, including the TUG test, lower limb strength, and functional scores. However, both isokinetic and isotonic training modes could be recommended after TKR because of no significant difference in the degree of improvement between these two groups. TRIAL REGISTRATION: Clinical trial registration number: NCT02938416. LEVEL OF EVIDENCE: I.


Assuntos
Artroplastia do Joelho , Treinamento de Força , Humanos , Idoso , Artroplastia do Joelho/efeitos adversos , Terapia por Exercício/métodos , Treinamento de Força/métodos , Joelho , Exercício Físico
19.
Medicine (Baltimore) ; 103(7): e37102, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38363950

RESUMO

BACKGROUND: Strengthening the hip muscles, particularly the abductors and rotators, has been reported beneficial for treating Patellofemoral pain syndrome (PFPS). Proprioceptive training (PT) is also shown to improve musculoskeletal pain and function in PFPS. The most appropriate treatment from these 2 is unclear. This study aimed to compare the effects of hip abductors and external rotator strengthening exercises along with conventional physical therapy (CPT) vs the proprioceptive training of the knee along with CPT in patients with PFPS. METHODS: Forty-five participants were divided into 3 groups, experimental group 1 (EG 1), experimental group 2 (EG 2), and control group (CG), with fifteen participants in each group. EG 1 received hip abductor and external rotator strengthening exercises in addition to CPT. EG 2 received proprioceptive training and CPT. CG received CPT alone. Intervention programs lasted for 4 weeks. The pain was measured by Kujala Anterior Knee Pain Scale (AKPS). The study was registered retrospectively in the protocol registration and results system (clinicaltrials.gov, ID: NCT05698797 on 26/01/2023). RESULTS: AKPS scores significantly (P < .001) improved in all 3 groups. A significant (P < .05) difference was also observed between all 3 groups. The greatest improvement was observed in EG 1, followed by EG 2 and CG. CONCLUSION: The addition of hip abductor and external rotator strengthening exercises to a 4-week CPT program showed a more significant improvement in AKPS scores than the addition of proprioceptive training in patients with PFPS.


Assuntos
Dor Musculoesquelética , Síndrome da Dor Patelofemoral , Treinamento de Força , Humanos , Treinamento de Força/métodos , Síndrome da Dor Patelofemoral/terapia , Estudos Retrospectivos , Terapia por Exercício/métodos , Força Muscular/fisiologia
20.
J Physiol Sci ; 74(1): 10, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38365576

RESUMO

BACKGROUND/OBJECTIVES: Myocardial infarction (MI) frequently leads to cardiac remodeling and failure with impaired life quality, playing an important role in cardiovascular deaths. Although physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases, the effects of strength training (ST) on the structural and functional aspects of cardiac remodeling need to be further documented. In this study, we aimed to investigate the role of a linear block ST protocol in the rat model of MI. METHODS AND RESULTS: After 6 weeks of MI induction or sham surgery, male adult rats performed ST for the following 12 weeks. The ladder-based ST program was organized in three mesocycles of 4 weeks, with one load increment for each block according to the maximal carrying load test. After 12 weeks, the infarcted-trained rats exhibited an increase in performance, associated with reduced cardiac hypertrophy and pulmonary congestion compared with the untrained group. Despite not changing MI size, the ST program partially prevented cardiac dilatation and ventricular dysfunction assessed by echocardiography and hemodynamics, and interstitial fibrosis evaluated by histology. In addition, isolated cardiac muscles from infarcted-trained rats had improved contractility parameters in a steady state, and in response to calcium or stimuli pauses. CONCLUSIONS: The ST in infarcted rats increased the capacity to carry mass, associated with attenuation of cardiac remodeling and pulmonary congestion with improving cardiac function that could be attributed, at least in part, to the improvement of myocardial contractility.


Assuntos
Insuficiência Cardíaca , Infarto do Miocárdio , Treinamento de Força , Humanos , Ratos , Masculino , Animais , Treinamento de Força/métodos , Remodelação Ventricular , Ratos Wistar , Insuficiência Cardíaca/tratamento farmacológico , Miocárdio/patologia , Infarto do Miocárdio/tratamento farmacológico , Cardiomegalia , Colágeno
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