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1.
J Musculoskelet Neuronal Interact ; 24(1): 38-46, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38427367

RESUMO

BFR) applied during sprint interval training (SIT) on performance and neuromuscular function. METHODS: Fifteen men completed a randomized bout of SIT with CBFR, IBFR, and without BFR (No-BFR), consisting of 2, 30-s maximal sprints on a cycle ergometer with a resistance of 7.5% of body mass. Concentric peak torque (CPT), maximal voluntary isometric contraction (MVIC) torque, and muscle thickness (MT) were measured before and after SIT, including surface electromyography (sEMG) recorded during the strength assessments. Peak and mean revolutions per minute (RPM) were measured during SIT and power output was examined relative to physical working capacity at the fatigue threshold (PWCFT). RESULTS: CPT and MVIC torque decreased from pre-SIT (220.3±47.6 Nm and 355.1±72.5 Nm, respectively) to post-SIT (147.9±27.7 Nm and 252.2±45.5 Nm, respectively, all P<0.05), while MT increased (1.77±0.31 cm to 1.96±0.30 cm). sEMG mean power frequency decreased during CPT (-12.8±10.5%) and MVIC (-8.7±10.2%) muscle actions. %PWCFT was greater during No-BFR (414.2±121.9%) than CBFR (375.9±121.9%). CONCLUSION: SIT with or without BFR induced comparable alterations in neuromuscular fatigue and sprint performance across all conditions, without affecting neuromuscular function.


Assuntos
Treinamento Intervalado de Alta Intensidade , Músculo Esquelético , Masculino , Humanos , Músculo Esquelético/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Eletromiografia , Contração Isométrica/fisiologia , Torque , Fadiga Muscular
2.
J Bodyw Mov Ther ; 37: 209-219, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38432808

RESUMO

OBJECTIVE: This study aimed investigate the effect of auriculotherapy on exercise-induced muscle fatigue, isometric torque production, and surface electromyographic activity (EMG). METHODS: Design: Randomized Crossover Trial. The sample consisted of 18 males' volunteers who exercised at least twice a week. THE SAMPLE WAS RANDOMLY ASSIGNED TO TWO GROUPS: Placebo Group (n = 9) and Treated Group (n = 9), and after seven days, the groups were crossed. The data analysis included 18 participants in each group. MAIN OUTCOME MEASURE: The muscle fatigue index, force production rate, and EMG of the quadriceps were used for evaluation. The evaluation moments included baseline pre-fatigue, baseline post-fatigue, 48 h post-intervention pre-fatigue, and 48 h post-intervention post-fatigue. Mixed two-way test ANOVA was used to compare times and groups. RESULTS: The fatigue index for peak torque and work showed no significant effect on time, groups, or interaction (p > 0.05). However, for isometric torque, force production rate, and EMG median frequency and average, the results indicate a positive change in values over time (p < 0.05) (with little practical relevance), with no differences observed between the groups or interaction (p > 0.05). CONCLUSIONS: In conclusion, auriculotherapy had no effect on exercise-induced muscle fatigue, isometric torque production, and surface electromyographic activity.


Assuntos
Auriculoterapia , Fadiga Muscular , Masculino , Humanos , Estudos Cross-Over , Análise de Variância , Músculo Quadríceps
3.
JCI Insight ; 9(6)2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38516893

RESUMO

Tubular aggregate myopathy (TAM) and Stormorken syndrome (STRMK) are clinically overlapping disorders characterized by childhood-onset muscle weakness and a variable occurrence of multisystemic signs, including short stature, thrombocytopenia, and hyposplenism. TAM/STRMK is caused by gain-of-function mutations in the Ca2+ sensor STIM1 or the Ca2+ channel ORAI1, both of which regulate Ca2+ homeostasis through the ubiquitous store-operated Ca2+ entry (SOCE) mechanism. Functional experiments in cells have demonstrated that the TAM/STRMK mutations induce SOCE overactivation, resulting in excessive influx of extracellular Ca2+. There is currently no treatment for TAM/STRMK, but SOCE is amenable to manipulation. Here, we crossed Stim1R304W/+ mice harboring the most common TAM/STRMK mutation with Orai1R93W/+ mice carrying an ORAI1 mutation partially obstructing Ca2+ influx. Compared with Stim1R304W/+ littermates, Stim1R304W/+Orai1R93W/+ offspring showed a normalization of bone architecture, spleen histology, and muscle morphology; an increase of thrombocytes; and improved muscle contraction and relaxation kinetics. Accordingly, comparative RNA-Seq detected more than 1,200 dysregulated genes in Stim1R304W/+ muscle and revealed a major restoration of gene expression in Stim1R304W/+Orai1R93W/+ mice. Altogether, we provide physiological, morphological, functional, and molecular data highlighting the therapeutic potential of ORAI1 inhibition to rescue the multisystemic TAM/STRMK signs, and we identified myostatin as a promising biomarker for TAM/STRMK in humans and mice.


Assuntos
Transtornos Plaquetários , Dislexia , Ictiose , Transtornos de Enxaqueca , Miopatias Congênitas Estruturais , Baço , Baço/anormalidades , Humanos , Animais , Camundongos , Criança , Baço/metabolismo , Cálcio/metabolismo , Miose/tratamento farmacológico , Miose/genética , Miose/metabolismo , Miopatias Congênitas Estruturais/tratamento farmacológico , Miopatias Congênitas Estruturais/genética , Miopatias Congênitas Estruturais/metabolismo , Proteína ORAI1/genética , Proteína ORAI1/metabolismo , Fadiga Muscular , Eritrócitos Anormais
4.
J Bodyw Mov Ther ; 37: 372-378, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38432831

RESUMO

INTRODUCTION: Reliable and valid measurements for shoulder muscular endurance should be available for clinical use. The posterior shoulder endurance test offers a potential clinical assessment, but its construct validity isn't available. Since a criterion measure of muscular endurance is not available, this study's purpose was to determine a reliable method for testing shoulder muscular endurance using an isokinetic dynamometer. METHODS: The test-retest reliability, standard error measurement, and minimal detectable change were calculated on four different paradigms to quantify muscular fatigue using two isokinetic speeds (60°sec-1,180°sec-1). Calculation paradigms included peak torque fatigue index (FI), average torque FI, area-under-the-curve FI, and peak torque decay slope. Testing occurred on two days. Repeated measures analysis of variance compared the two peak torque decay slopes across both testing days. RESULTS: Superior reliability was found within the decay slope measurements at both 60°sec-1 (ICC = 0.941) and 180°sec-1 (ICC = 0.764) speeds, with the 60°sec-1 decay slope being the highest reliability between the two angular velocities. There was a greater amount of fatigue in the 60°sec-1 decay slope compared to the 180°sec-1 decay slope. CONCLUSION: Using the decay slope of isokinetic shoulder horizontal abduction at 60°sec-1 is a reliable method to validate other muscular endurance clinical measures. Rehabilitation specialists should utilize the decay slope of the isokinetic dynamometry to monitor responsiveness.


Assuntos
Fadiga Muscular , Ombro , Humanos , Terapia por Exercício , Reprodutibilidade dos Testes
5.
PLoS One ; 19(2): e0298291, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38319955

RESUMO

BACKGROUND: Jump tests have applications in fatigue monitoring, training intervention evaluations, and talent identification in cycling populations. Due to competitive cycling's inherent travel demands, linear position transducers (LPTs) are suitable for assessing jump performance in this population as they are a mobile and validated technology. Understanding the reliability and sensitivity of LPTs in assessing jump performance in cycling populations is required to support the development of sports science protocols. Using an LPT, this study aimed to determine the reliability and sensitivity of countermovement jump (CMJ) variables in road cyclists. METHODS: Ten national-level male road cyclists performed three maximal CMJ trials twice per week for two weeks, with an LPT measuring force, power, velocity, repetition rate, vertical distance, and concentric time from each trial. Using the mean and best CMJ results from three trials per testing session, the upper limit 90% confidence interval for the coefficient of variation (CV) and smallest worthwhile change (SWC) determined inter-day and -week reliability (CV ≤ 10%) and sensitivity (acceptable sensitivity = CV ≤ SWC) for CMJ variables. RESULTS: Mean power and force, velocity (mean and peak), vertical distance (VD), and concentric time had acceptable inter-day and -week reliability when using either the mean or best CMJ results (CV upper limit 90% confidence interval range = 3.54-10.13%). Moreover, the CV and SWC were typically lower when based on the mean rather than the best of three CMJ trials. Lastly, poor sensitivity (CV > SWC) was evident for all CMJ variables. CONCLUSIONS: CMJ-derived mean power and force, velocity (peak and mean), VD, and concentric time have acceptable inter-day and -week reliability when assessed via an LPT in national-level road cyclists. When using an LPT, sports scientists should consider that, while they typically have poor sensitivity, the reliability of CMJ-derived variables improves when expressed as the mean of three trials in national-level road cyclists.


Assuntos
Força Muscular , Esportes , Masculino , Humanos , Reprodutibilidade dos Testes , Teste de Esforço/métodos , Fadiga Muscular
6.
PLoS One ; 19(2): e0293417, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38346010

RESUMO

After a unilateral muscle exercise, the performance of the non-exercised contralateral limb muscle can be also impaired. This crossover fatigue phenomenon is still debated in the literature and very few studies have investigated the influence of eccentric contractions. This study was designed to assess neuromuscular adaptations involved in the crossover fatigue of the non-exercised contralateral knee flexor muscles. Seventeen healthy young men performed a unilateral submaximal eccentric exercise of the right knee flexors until a 20% reduction in maximal voluntary isometric contraction torque was attained in the exercised limb. Before (PRE), immediately after exercise cessation (POST) and 24 hours later (POST24), neuromuscular function and perceived muscle soreness were measured in both the exercised limb and non-exercised limb. In addition, global perceived fatigue was assessed at each measurement time. At POST, significant reductions in maximal voluntary isometric contraction were observed in the exercised limb (-28.1%, p < 0.001) and in the non-exercised limb (-8.5%, p < 0.05), evidencing crossover fatigue. At POST, voluntary activation decreased in the exercised limb only (-6.0%, p < 0.001), while electrically evoked potentiated doublet torque was impaired in both the exercised limb and the non-exercised limb (-11.6%, p = 0.001). In addition, global perceived fatigue significantly increased at POST (p < 0.001). At POST24, all measured variables returned to PRE values, except for perceived muscle soreness scores exhibiting greater values than PRE (p < 0.05). A possible cumulative interaction between peripheral alterations and global perceived fatigue may account for the immediate crossover fatigue observed in the non-exercised limb.


Assuntos
Exercício Físico , Mialgia , Masculino , Humanos , Exercício Físico/fisiologia , Joelho/fisiologia , Articulação do Joelho/fisiologia , Músculo Esquelético/fisiologia , Fadiga Muscular/fisiologia , Contração Isométrica/fisiologia , Fadiga , Contração Muscular/fisiologia , Eletromiografia
7.
Math Biosci Eng ; 21(1): 144-169, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38303417

RESUMO

Recently, fuzzy dispersion entropy (DispEn) has attracted much attention as a new nonlinear dynamics method that combines the advantages of both DispEn and fuzzy entropy. However, it suffers from limitation of insensitivity to dynamic changes. To solve this limitation, we proposed fractional fuzzy dispersion entropy (FFDispEn) based on DispEn, a novel fuzzy membership function and fractional calculus. The fuzzy membership function was defined based on the Euclidean distance between the embedding vector and dispersion pattern. Simulated signals generated by the one-dimensional (1D) logistic map were used to test the sensitivity of the proposed method to dynamic changes. Moreover, 29 subjects were recruited for an upper limb muscle fatigue experiment, during which surface electromyography (sEMG) signals of the biceps brachii muscle were recorded. Both simulated signals and sEMG signals were processed using a sliding window approach. Sample entropy (SampEn), DispEn and FFDispEn were separately used to calculate the complexity of each frame. The sensitivity of different algorithms to the muscle fatigue process was analyzed using fitting parameters through linear fitting of the complexity of each frame signal. The results showed that for simulated signals, the larger the fractional order q, the higher the sensitivity to dynamic changes. Moreover, DispEn performed poorly in the sensitivity to dynamic changes compared with FFDispEn. As for muscle fatigue detection, the FFDispEn value showed a clear declining tendency with a mean slope of -1.658 × 10-3 as muscle fatigue progresses; additionally, it was more sensitive to muscle fatigue compared with SampEn (slope: -0.4156 × 10-3) and DispEn (slope: -0.1675 × 10-3). The highest accuracy of 97.5% was achieved with the FFDispEn and support vector machine (SVM). This study provided a new useful nonlinear dynamic indicator for sEMG signal processing and muscle fatigue analysis. The proposed method may be useful for physiological and biomedical signal analysis.


Assuntos
Fadiga Muscular , Músculo Esquelético , Humanos , Fadiga Muscular/fisiologia , Entropia , Músculo Esquelético/fisiologia , Eletromiografia/métodos , Braço , Algoritmos
8.
Emerg Infect Dis ; 30(3): 539-547, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38407166

RESUMO

This study aimed to estimate the incidence rates of post-COVID-19 fatigue and chronic fatigue and to quantify the additional incident fatigue caused by COVID-19. We analyzed electronic health records data of 4,589 patients with confirmed COVID-19 during February 2020-February 2021 who were followed for a median of 11.4 (interquartile range 7.8-15.5) months and compared them to data from 9,022 propensity score-matched non-COVID-19 controls. Among COVID-19 patients (15% hospitalized for acute COVID-19), the incidence rate of fatigue was 10.2/100 person-years and the rate of chronic fatigue was 1.8/100 person-years. Compared with non-COVID-19 controls, the hazard ratios were 1.68 (95% CI 1.48-1.92) for fatigue and 4.32 (95% CI 2.90-6.43) for chronic fatigue. The observed association between COVID-19 and the significant increase in the incidence of fatigue and chronic fatigue reinforces the need for public health actions to prevent SARS-CoV-2 infections.


Assuntos
COVID-19 , Síndrome de Fadiga Crônica , Humanos , Incidência , COVID-19/epidemiologia , Fadiga Muscular , SARS-CoV-2
9.
J Sport Rehabil ; 33(3): 181-188, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38350443

RESUMO

CONTEXT: Blood flow restriction (BFR) is a rehabilitation tool which may introduce a constraint, similar to muscle fatigue, that challenge patients' sensorimotor system during balance exercises. The purpose of our study was to examine whether adding BFR to dynamic balance exercises produced a decrease in balance performance and an increase in ratings of perceived exertion and instability in individuals with chronic ankle instability (CAI) compared with dynamic balance exercises without BFR. DESIGNS: Crossover design. METHODS: Our sample included N = 25 young adults with a history of CAI. Participants completed 2 laboratory visits. At each visit, participants completed 4 sets (30×-15×-15×-15×) of dynamic balance exercises, performed similar to the modified star excursion balance test (SEBT), once with BFR and once with control (no BFR) conditions. We measured composite SEBT scores at baseline and during the final repetitions of each set of balance exercise (sets 1-4). We also measured ratings of perceived exertion and instability following each balance exercise set. RESULTS: We observed no difference in composite SEBT scores between conditions at baseline; however, composite SEBT scores were significantly lower during all balance exercises sets 1 to 4 with the BFR condition compared with control. During the BFR condition, composite SEBT scores were significantly lower during all balance exercise sets compared with baseline. During the control condition, composite SEBT scores did not significantly change between baseline and each balance exercise set. Ratings of perceived exertion and instability scores were significantly greater in the BFR group compared with the control group during all balance exercise sets. CONCLUSIONS: Individuals with CAI demonstrated lower composite SEBT scores and greater perceived instability and exertion during dynamic balance exercise with BFR compared to without BFR. BFR introduced a novel muscle fatigue constraint during dynamic balance exercises in individuals with CAI. Additional research is needed to determine if adding BFR to balance training could improve clinical outcomes in CAI patients.


Assuntos
Tornozelo , Instabilidade Articular , Adulto Jovem , Humanos , Terapia por Exercício , Exercício Físico , Fadiga Muscular
10.
Sci Data ; 11(1): 208, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38360835

RESUMO

Measuring muscle fatigue involves assessing various components within the motor system. While subjective and sensor-based measures have been proposed, a comprehensive comparison of these assessment measures is currently lacking. This study aims to bridge this gap by utilizing three commonly used measures: participant self-reported perceived muscle fatigue scores, a sports physiotherapist's manual palpation-based muscle tightness scores, and surface electromyography sensors. Compensatory muscle fatigue occurs when one muscle group becomes fatigued, leading to the involvement and subsequent fatigue of other muscles as they compensate for the workload. The evaluation of compensatory muscle fatigue focuses on nine different upper body muscles selected by the sports physiotherapist. With a cohort of 30 male subjects, this study provides a valuable dataset for researchers and healthcare practitioners in sports science, rehabilitation, and human performance. It enables the exploration and comparison of diverse methods for evaluating different muscles in isometric contraction.


Assuntos
Eletromiografia , Contração Isométrica , Fadiga Muscular , Músculo Esquelético , Humanos , Masculino , Eletromiografia/métodos , Contração Isométrica/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Autorrelato
11.
J Appl Physiol (1985) ; 136(4): 659-676, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38357723

RESUMO

High-level athletic performances may be a proxy for the trajectory of optimal function of human biology with advanced aging and the differences between males and females. Males are faster, stronger, and more powerful than females and these physical attributes decline dramatically with advanced aging for both sexes. Experimental mechanistic studies determine the physiological mechanisms for these sex and age differences in human physical performance. The assumption however, that real-world performances solely reflect the biological and physiological differences between the sexes and with advanced aging, even among elite athletes, is not complete. This review presents evidence that an integrated approach encompassing analysis of real-world data and experimental mechanistic studies is necessary to determine the biological and sociocultural factors attributed to the limits of performance with aging and between males and females. First, experimental studies are presented that focus on the sex and age differences in performance fatigability that determine the physiological mechanisms of absolute and relative exercise performance. Second, analysis of current and historical real-world data including world records, and performances of elite, collegiate, and competitive age-group athletes are highlighted. These data illustrate that the upper limits of physical performance that have changed historically, and other factors such as sociocultural influences, explain the widening of the sex and age gaps in human performance observed in real-world data even in present-day performances. These approaches have broader significance when applied to understanding the impact of the historically low representation of females and minority groups in biomedical research on health outcomes.


Assuntos
Desempenho Atlético , Caracteres Sexuais , Humanos , Masculino , Feminino , Fadiga Muscular/fisiologia , Desempenho Atlético/fisiologia , Envelhecimento/fisiologia , Exercício Físico/fisiologia , Fadiga
12.
J Biomech ; 164: 111987, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38342053

RESUMO

Muscle fatigue is prevalent across different aspects of daily life. Tracking muscle fatigue is useful to understand muscle overuse and possible risk of injury leading to musculoskeletal disorders. Current fatigue models are not suitable for real-world settings as they are either validated using simulations or non-functional tasks. Moreover, models that capture the changes to muscle activity due to fatigue either assume a linear relationship between muscle activity and muscle force or utilize a simple muscle model. Personalised electromygraphy (EMG)-driven musculoskeletal models (pEMS) offer person-specific approaches to model muscle and joint kinetics during a wide repertoire of daily life tasks. These models utilize EMG, thus capturing central fatigue-dependent changes in multi-muscle bio-electrical activity. However, the peripheral muscle force decay is missing in these models. Thus, we studied the influence of fatigue on a large scale pEMS of the trunk. Eleven healthy participants performed functional asymmetric lifting task. Average peak body-weight normalized lumbosacral moments (BW-LM) were estimated to be 2.55 ± 0.26 Nm/kg by reference inverse dynamics. After complete exhaustion of the lower back, the pEMS overestimated the peak BW-LM by 0.64 ± 0.37 Nm/kg. Then, we developed a time-varying muscle force decay model resulting in a time-varying pEMS (t-pEMS). This reduced the difference between BW-LM estimated by the t-pEMS and reference to 0.49 ± 0.14 Nm/kg. We also showed that five fatiguing contractions are sufficient to calibrate the t-pEMS. Thus, this study presents a person and muscle specific model to track fatigue during functional tasks.


Assuntos
Remoção , Coluna Vertebral , Humanos , Eletromiografia/métodos , Coluna Vertebral/fisiologia , Articulações/fisiologia , Região Lombossacral/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia
13.
Hum Mov Sci ; 94: 103182, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38401336

RESUMO

Predictive simulation of human motion could provide insight into optimal techniques. In repetitive or long-duration tasks, these simulations must predict fatigue-induced adaptation. However, most studies minimize cost function terms related to actuator activations, assuming it minimizes fatigue. An additional modeling layer is needed to consider the previous use of muscles to reveal adaptive strategies to the decreased force production capability. Here, we propose interfacing Xia's three-compartment fatigue dynamics model with rigid-body dynamics. A stabilization invariant was added to Xia's model. We simulated the maximum repetition of dumbbell biceps curls as an optimal control problem (OCP) using direct multiple shooting. We explored three cost functions (minimizing torque, fatigue, or both) and two OCP formulations (full-horizon and sliding-horizon approaches). We adapted Xia's model by adding a stabilization invariant coefficients S=105 for direct multiple shooting. Sliding-horizon OCPs achieved 20 to 21 repetitions. The kinematic strategy slowly deviated from a plausible dumbbell lifting task to a swinging strategy as fatigue onset increasingly compromised the humerus to remain vertical. In full-horizon OCPs, the latter kinematic strategy was used over the whole motion, resulting in 32 repetitions. We showed that sliding-horizon OCPs revealed a reactive strategy to fatigue when only torque was included in the cost function, whereas an anticipatory strategy was revealed when the fatigue term was included in the cost function. Overall, the proposed approach has the potential to be a valuable tool in optimizing performance and helping reduce fatigue-related injuries in a variety of fields.


Assuntos
Fadiga Muscular , Músculo Esquelético , Humanos , Músculo Esquelético/fisiologia , Fenômenos Biomecânicos , Fadiga Muscular/fisiologia
14.
Pain Res Manag ; 2024: 9982411, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38312327

RESUMO

Background: Reaction time is a reliable indicator of the velocity and efficiency of neuromuscular control and may be associated with fear-avoidance beliefs. However, the effect of exercise-induced muscle fatigue on reaction time in chronic low back pain (cLBP) and its relationship with fear-avoidance beliefs remains poorly understood. Objectives: This study aimed to reveal the relationship between fear-avoidance beliefs and reaction time changes before and after exercise-induced muscle fatigue in cLBP. Methods: Twenty-five patients with cLBP were tested by the Biering-Sorensen test (BST) to induce exhaustive muscle fatigue. Total reaction time (TRT), premotor time (PMT), and electromechanical delay (EMD) of dominated deltoid muscle were recorded by surface electromyography during the arm-raising task with visual cues before and after muscle fatigue. The mean difference (MD) of TRT (MDTRT), PMT (MDPMT), and EMD (MDEMD) was calculated from the changes before and after muscle fatigue. Fear-avoidance beliefs questionnaire (FABQ) was applied to evaluate fear-avoidance beliefs before muscle fatigue. In addition, the duration time of BST was recorded for each subject. Results: TRT and PMT of dominated deltoid muscle were prolonged after exercise-induced muscle fatigue (Z = 3.511, p < 0.001; t = 3.431, p = 0.001), while there was no statistical difference in EMD (Z = 1.029, p = 0.304). Correlation analysis showed that both the MDTRT and MDPMT were positively correlated with FABQ (r = 0.418, p = 0.042; r = 0.422, p = 0.040). Conclusions: These findings suggested that we should pay attention to both muscle fatigue-induced reaction time delay in cLBP management and the possible psychological mechanism involved in it. Furthermore, this study implied that FABQ-based psychotherapy might serve as a potential approach for cLBP treatment by improving reaction time delay. This trial is registered with ChiCTR2300074348.


Assuntos
Dor Lombar , Humanos , Dor Lombar/terapia , Fadiga Muscular/fisiologia , Tempo de Reação , Eletromiografia , Medo/psicologia , Inquéritos e Questionários , Avaliação da Deficiência
16.
J Biomech ; 163: 111905, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38183760

RESUMO

Previous studies have identified some sex differences in how individual muscles change their activation during repetitive multi-joint arm motion-induced fatigue. However, little is known about how indicators of multi-muscle coordination change with fatigue in males and females. Fifty-six (29 females) asymptomatic young adults performed a repetitive, forward-backward pointing task until scoring 8/10 on a Borg CR10 scale while surface electromyographic activity of upper trapezius, anterior deltoid, biceps brachii, and triceps brachii was recorded. Activation coefficient, synergy structure, and relative weight of each muscle within synergies were calculated using the non-negative matrix factorization method. Two muscle synergies were extracted from the fatiguing task. The synergy structures were mostly preserved after fatigue, while the activation coefficients were altered. A significant Sex × Fatigue interaction effect showed more use of the anterior deltoid in males especially before fatigue in synergy 1 during shoulder stabilization (p = 0.04). As for synergy 2, it was characterized by variations in the relative weight of biceps, which was higher by 16 % in females compared to males (p = 0.04), and increased with fatigue (p = 0.03) during the elbow flexion acceleration phase and the deceleration phase of the backward pointing movement. Findings suggest that both sexes adapted to fatigue similarly, using fixed synergy structures, with alterations in synergy activation patterns and relative weights of individual muscles. Results support previous findings of an important role for the biceps and anterior deltoid in explaining sex differences in patterns of repetitive motion-induced upper limb fatigue.


Assuntos
Fadiga Muscular , Ombro , Feminino , Humanos , Masculino , Adulto Jovem , Eletromiografia , Movimento/fisiologia , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Ombro/fisiologia
17.
Am J Physiol Cell Physiol ; 326(3): C795-C809, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38223925

RESUMO

Mitsugumin 23 (MG23) has been identified as a ball-shaped cation channel in the sarcoplasmic reticulum (SR) but its physiological role remains unclear. This study aimed to examine the contribution of MG23 to Ca2+ storage function in skeletal muscle by using Mg23-knockout (Mg23-/-) mice. There was no difference in the isometric specific force of the extensor digitorum longus (EDL) and soleus (SOL) muscles between Mg23-/- and wild-type (Wt) mice. In Mg23-/- mice, the calsequestrin 2 content in the EDL muscle and SR Ca2+-ATPase 2 content in the SOL were increased. We have examined SR and myofibril functions using mechanically skinned fibers and determined their fiber types based on the response to Sr2+, which showed that Mg23-/- mice, compared with Wt, had: 1) elevated total Ca2+ content in the membranous components including SR, mitochondria, and transverse tubular system referred to as endogenous Ca2+ content, in both type I and II fibers of the EDL and SOL; 2) increased maximal Ca2+ content in both type I and II fibers of the EDL and SOL; 3) decreased SR Ca2+ leakage in type I fibers of the SOL; and 4) enhanced SR Ca2+ uptake in type I fibers of the SOL, although myofibril function was not different in both type I and II fibers of the SOL and EDL muscles. These results suggest that MG23 decreases SR Ca2+ storage in both type I and type II fibers, likely due to increased SR Ca2+ leakage.NEW & NOTEWORTHY The function of calcium storage within sarcoplasmic reticulum (SR) plays a pivotal role in influencing the health and disease states of skeletal muscle. In the present study, we demonstrated that mitsgumin 23, a novel non-selective cation channel, modifies SR Ca2+ storage in skeletal muscle fibers. These findings provide valuable insights into the physiological regulation of Ca2+ in skeletal muscle, offering significant potential for uncovering the mechanisms underlying muscle fatigue, muscle adaptation, and muscle diseases.


Assuntos
Músculo Esquelético , Retículo Sarcoplasmático , Animais , Camundongos , Cátions , Fadiga Muscular , Fibras Musculares Esqueléticas
18.
Int J Sports Physiol Perform ; 19(3): 299-306, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38194958

RESUMO

PURPOSE: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake (V˙O2) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. METHODS: Twenty trained CrossFitters performed Fran at maximal exertion. V˙O2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. RESULTS: A marked increase in V˙O2 kinetics was observed at the beginning of Fran, remaining elevated until the end (V˙O2peak: 49.2 [3.7] mL·kg-1·min-1, V˙O2 amplitude: 35.8 [5.2] mL·kg-1·min-1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. CONCLUSIONS: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue.


Assuntos
Fadiga , Consumo de Oxigênio , Humanos , Consumo de Oxigênio/fisiologia , Fadiga Muscular/fisiologia , Oxigênio , Músculos
19.
Physiol Rep ; 12(1): e15892, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38172088

RESUMO

The absolute magnitude and rate of arterial desaturation each independently impair whole-body aerobic exercise. This study examined potential mechanisms underlying the rate-dependent relationship. Utilizing an exercise protocol involving unilateral, intermittent, isometric knee extensions (UIIKE), we provided sufficient reperfusion time between contractions to reduce the accumulation of intramuscular metabolic by-products that typically stimulate muscle afferents. The objective was to create a milieu conducive to accentuating any influence of arterial desaturation rate on muscular fatigue. Eight participants completed four UIIKE sessions, performing one 3 s contraction every 30s at a perceived intensity of 50% MVC for 25 min. Participants voluntarily adjusted their force generation to maintain perceptual effort at 50% MVC without feedback. Reductions in inspired oxygen fraction (FI O2 ) decreased arterial saturation from >98% to 70% with varying rates in three trials: FAST (5.3 ± 1.3 min), MED (11.8 ± 2.7 min), and SLOW (19.9 ± 3.7 min). FI O2 remained at 0.21 during the control trial. Force generation and muscle activation remained at baseline levels throughout UIIKE trials, unaffected by the magnitude or rate of desaturation. Minute ventilation increased with hypoxia (p < 0.05), and faster desaturation rates magnified this response. These findings demonstrate that arterial desaturation magnitude and rate independently affect ventilation, but do not influence fatigue development during UIIKE.


Assuntos
Hipóxia , Consumo de Oxigênio , Humanos , Projetos Piloto , Consumo de Oxigênio/fisiologia , Hipóxia/metabolismo , Oxigênio/metabolismo , Fadiga Muscular/fisiologia , Músculo Esquelético/metabolismo , Contração Isométrica
20.
BMC Complement Med Ther ; 24(1): 44, 2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38245778

RESUMO

BACKGROUND: Acupuncture is known to improve exercise capacity in patients with chronic obstructive pulmonary disease (COPD), but its mechanism remains unknown. Whether acupuncture improves exercise capacity in patients with COPD through alleviation of leg fatigue and dyspnea is examined by applying causal mediation analysis to previous trial data. METHODS: Sixty-two patients with COPD completed treatments with either real or placebo acupuncture once a week for 12 weeks. Walk distance measured using the 6-minute walk test and intensities of leg fatigue and dyspnea in the modified Borg scale were evaluated at baseline and after treatment. The intervention effect of acupuncture against the placebo acupuncture on two mediators, changes in leg fatigue and dyspnea, and whether they mediated improvements in walk distance, were analyzed. RESULTS: Linear regression analysis showed that the unstandardized regression coefficients [95% confidence interval (CI)] for the intervention effect by acupuncture were -4.9 (-5.8--4.0) in leg fatigue and -3.6 (-4.3--2.9) in dyspnea. Mediation analysis showed that when changes in leg fatigue were considered as a mediator, direct effect, indirect effect and proportion mediated were 47.1 m (95% CI, 4.6-85.1), 34.3 m (-2.1-82.1), and 42.1%, respectively, and when changes in dyspnea were considered as a mediator, they were 9.8 m (-32.9-49.9), 72.5 m (31.3-121.0), and 88.1%, respectively, and the effects of joint mediator were -5.8 m (-55.4-43.9), 88.9 m (32.7-148.5), and 107.0%, respectively. CONCLUSION: The improvement in exercise capacity by acupuncture is explained by changes in both leg fatigue and dyspnea.


Assuntos
Terapia por Acupuntura , Tolerância ao Exercício , Doença Pulmonar Obstrutiva Crônica , Humanos , Dispneia/etiologia , Dispneia/terapia , Perna (Membro) , Análise de Mediação , Doença Pulmonar Obstrutiva Crônica/complicações , Doença Pulmonar Obstrutiva Crônica/terapia , Fadiga Muscular , Ensaios Clínicos Controlados Aleatórios como Assunto
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