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1.
Med Sci Sports Exerc ; 55(2): 301-310, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36635860

RESUMO

INTRODUCTION: Scheduling concurrent training (CT) during the in-season microcycle in field-based team sport is driven by prematch and postmatch recovery. This study examined the neuromuscular function, fatigue, and soreness responses to CT administered 48 h (match day (MD) + 2) versus 72 h (MD + 3) after match. METHODS: Ten male recreational-level team sport athletes were monitored daily during two 5-d microcycles, which began with a simulated match (Soccer-specific Aerobic Field Test (SAFT90)) and CT performed either 48 or 72 h after match. Maximal voluntary force, quadriceps maximum EMG, voluntary activation, muscle contractile function (evoked twitch responses), muscle soreness, and fatigue were assessed immediately before and after the SAFT90, and every 24 up to 96 h after match. Outcome measures were also assessed immediately after CT. The CT consisted of an intermittent sprint protocol and a lower limb resistance training session separated by 1 h. RESULTS: Immediately after the SAFT90 in both conditions, maximal voluntary force was below baseline (mean change (Δ), -14.6% ± 10.0%; P = 0.03), recovering 48 h post. Quadriceps contractile function (Δ, -31.5% ± 11.4%; P = 0.003) and voluntary activation (Δ, -8.9 ± 6.2%; P = 0.003) were also hampered after the SAFT90, recovering 24 h post in both conditions. In addition, the SAFT90 elicited elevated levels of fatigue and muscle soreness that recovered 24 h after the SAFT90 before increasing at 72 and 96 h post in the MD + 2 and MD + 3 conditions, respectively. CONCLUSIONS: Recovery of fatigue was only observed at the end of the microcycle when CT was prescribed on MD + 2. Therefore, CT scheduled early (MD + 2) in the microcycle might avoid compromising forthcoming match preparation.


Assuntos
Mialgia , Futebol , Humanos , Masculino , Fadiga Muscular/fisiologia , Futebol/fisiologia , Contração Muscular/fisiologia , Fadiga
2.
Sci Rep ; 13(1): 1282, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36690648

RESUMO

In this study, Kinesio tape (KT) was applied in two different directions to the gastrocnemius muscle, the most important muscle in stance stability, to investigate the effect of different taping directions on overall balance and sensation systems before versus after muscle fatigue. The participants, comprising 45 healthy athletes, were randomly divided into three groups: the placebo taping group (PTG), the facilitation KT group (FKTG), and the inhibition KT group (IKTG). The tests involved in this study were a balance test, a superficial sensory function test, and a combined cortical sensation test. The data from these tests were collected before taping, after taping and a 10-min rest, and immediately after continuous heel raises were performed to fatigue. The results of the balance tests showed no significant group × time interaction, whether subjects stood barefoot on one foot or stood on a soft mat with eyes open or closed (p > 0.05). Only the sway distance and sway velocity of the center of pressure (COP) when subjects stood barefoot on one foot with eyes open were significantly higher in the inhibition taping group than in the placebo taping group (p < 0.05). In addition, significant differences were noted in the sway area and sway distance of the COP before taping, after taping, and after exercise to fatigue when the participants stood on the soft mat with their eyes open (p < 0.05). When the participants stood on the soft mat on one foot with their eyes closed, no significant differences were noted among the groups. When subjects stood on a soft mat on one foot with eyes open, significant improvements were noted after fatiguing exercise versus before taping for all three groups (p < 0.05). The results of the superficial sensory test showed no significant group × time interaction and no difference among the three taping conditions or before/after taping and after fatiguing exercise. Only in the two-point discrimination test was a sensory difference observed, with the facilitation taping group having a significantly shorter discrimination distance than the placebo taping and inhibition taping groups (p < 0.05). The present study showed that KT application for a simple balance task (e.g., barefoot on a hard floor with eyes open) may slightly influence postural control, especially when the inhibition method is used. However, more difficult balance tasks (e.g., barefoot on a soft mat with eyes closed) show no effect of KT application-either the facilitation method or the inhibition method-on posture control.


Assuntos
Fita Atlética , Fadiga Muscular , Humanos , Fadiga Muscular/fisiologia , Equilíbrio Postural/fisiologia , Músculo Esquelético/fisiologia , Atletas
3.
Sensors (Basel) ; 23(2)2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36679631

RESUMO

Surface electromyography (sEMG) is the acquisition, from the skin, of the electrical signal produced by muscle activation. Usually, sEMG is measured through electrodes with electrolytic gel, which often causes skin irritation. Capacitive contactless electrodes have been developed to overcome this limitation. However, contactless EMG devices are still sensitive to motion artifacts and often not comfortable for long monitoring. In this study, a non-invasive contactless method to estimate parameters indicative of muscular activity and fatigue, as they are assessed by EMG, through infrared thermal imaging (IRI) and cross-validated machine learning (ML) approaches is described. Particularly, 10 healthy participants underwent five series of bodyweight squats until exhaustion interspersed by 1 min of rest. During exercising, the vastus medialis activity and its temperature were measured through sEMG and IRI, respectively. The EMG average rectified value (ARV) and the median frequency of the power spectral density (MDF) of each series were estimated through several ML approaches applied to IRI features, obtaining good estimation performances (r = 0.886, p < 0.001 for ARV, and r = 0.661, p < 0.001 for MDF). Although EMG and IRI measure physiological processes of a different nature and are not interchangeable, these results suggest a potential link between skin temperature and muscle activity and fatigue, fostering the employment of contactless methods to deliver metrics of muscular activity in a non-invasive and comfortable manner in sports and clinical applications.


Assuntos
Músculo Esquelético , Músculo Quadríceps , Humanos , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiologia , Eletromiografia/métodos , Músculo Quadríceps/fisiologia , Fadiga , Aprendizado de Máquina Supervisionado , Fadiga Muscular/fisiologia
4.
Int J Sports Physiol Perform ; 18(1): 55-60, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36521189

RESUMO

PURPOSE: To examine the general perspectives of elite soccer players on the time course of perceived postmatch fatigue and the influence of away matches on subjective perceptions. METHODS: Adopting a cross-sectional study design, we invited 371 subjects from 14 top-division European clubs competing in the Belgian First Division A, English Premier League, French Ligue 1, Italian Serie A, Portuguese Primeira Liga, Russian Premier League, and Swiss Premier League to take part in a short survey on general issues relating to postmatch fatigue measurement and tracking in professional soccer. RESULTS: Three hundred male professional soccer players completed the short questionnaire. For perceptions relevant to the time course of postmatch fatigue, two-thirds of respondents (67%) indicated higher postmatch fatigue perceived 2 days (48 h) after an official competition. Among these respondents, a higher proportion of answers was observed in wide midfielders (74%), attackers (74%), and central midfielders (68%). Approximately two-thirds of respondents (63%) indicated more than usual and much more than usual perceived postmatch fatigue following away matches. CONCLUSIONS: For the first time, our investigation addressed practical aspects that remained unexplored and fundamental to the definition of an optimal player management process following a competition. From a practical standpoint, perspectives of individual elite soccer players substantiated the notion of implementing processes with dedicated recovery protocols within 48 hours postmatch and highlighted the need for differential strategies addressing the additional burden of away matches and travel.


Assuntos
Desempenho Atlético , Futebol , Humanos , Masculino , Estudos Transversais , Fadiga , Fadiga Muscular , Viagem
5.
Rev. bras. med. esporte ; 29: e2022_0167, 2023. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1394838

RESUMO

ABSTRACT Introduction: Skiing is a sport that demands the high performance of motor coordination with high energy consumption, factors that strongly influence muscle fatigue. Athletes who experience this phenomenon tend to present a decline in performance, generating psychological irritability and impairment in concentration. Diet is closely related to athletic performance, but the proper prescription for skiing athletes still lacks studies. Objective: To explore the methods of recovery from sports fatigue in skiers by providing up-to-date perspectives for effective nutritional intervention during the recovery stage. Methods: Seven young male skiers were selected as research subjects, and caloric intake, among other conditions, was recorded in detail. After three weeks, indices of body weight, body fat rate, serum metabolism, cardiopulmonary capacity, and energy metabolism, among other relevant information, were duly recorded and compared. Results: The intervention did not significantly impact lean body mass indices (p>0.05). The athletes' body weight decreased significantly, and the body fat rate decreased significantly after the nutritional intervention; The analyzed biomarkers were positively impacted, except the urea nitrogen concentration that showed a tendency to increase after the nutritional intervention, an effect that may be linked to the proportional increase of protein intake. Conclusion: The proposed nutritional intervention positively impacted the skiers' energy metabolism, directly impacting the athletes' recovery from sports fatigue. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.


RESUMO Introdução: O esqui é um esporte que exige alto desempenho de coordenação motora com um elevado consumo de energia, fatores que influenciam fortemente a fadiga muscular. Atletas que experienciam esse fenômeno, tendem a apresentar um declínio no nível do desempenho, gerando irritabilidade psicológica e prejuízos na concentração. A dieta está intimamente relacionada ao desempenho atlético, porém a receita adequada para os atletas em esqui ainda carece de estudos. Objetivo: Explorar os métodos de recuperação da fadiga esportiva nos esquiadores fornecendo perspectivas atualizadas para uma intervenção nutricional eficaz durante a etapa de recuperação. Métodos: Sete jovens esquiadores do sexo masculino foram selecionados como sujeitos da pesquisa, e a ingestão calórica, entre outras condições foram detalhadamente registradas. Após três semanas, índices de peso corporal, taxa de gordura corporal, metabolismo sérico, capacidade cardiopulmonar, metabolismo energético, entre outras informações relevantes foram devidamente registradas e comparadas. Resultados: A intervenção não impactou significativamente nos índices de massa magra corporal (p>0,05). O peso corporal dos atletas diminuiu significativamente e a taxa de gordura corporal diminuiu significativamente após a intervenção nutricional; os biomarcadores analisados foram positivamente impactados, a exceção da concentração de nitrogênio ureico que apresentou tendência de alta após a intervenção nutricional, efeito que pode estar atrelado ao aumento proporcional da ingesta proteica. Conclusão: A proposta de intervenção nutricional apresentou impactos positivos no metabolismo energético dos esquiadores, impactando diretamente na recuperação da fadiga esportiva dos atletas. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.


RESUMEN Introducción: El esquí es un deporte que exige un alto rendimiento de coordinación motora con un elevado consumo de energía, factores que influyen fuertemente en la fatiga muscular. Los deportistas que experimentan este fenómeno, tienden a presentar un descenso en el nivel de rendimiento, generando irritabilidad psicológica y daños en la concentración. La dieta está estrechamente relacionada con el rendimiento deportivo, pero la prescripción adecuada para los atletas de esquí aún carece de estudios. Objetivo: Explorar los métodos de recuperación de la fatiga deportiva en los esquiadores proporcionando perspectivas actualizadas para una intervención nutricional eficaz durante la etapa de recuperación. Métodos: Se seleccionaron siete jóvenes esquiadores varones como sujetos de investigación, y se registró detalladamente la ingesta calórica, entre otras condiciones. Al cabo de tres semanas, se registraron y compararon debidamente los índices de peso corporal, el índice de grasa corporal, el metabolismo sérico, la capacidad cardiopulmonar y el metabolismo energético, entre otros datos relevantes. Resultados: La intervención no tuvo un impacto significativo en los índices de masa corporal magra (p>0,05). El peso corporal de los atletas disminuyó significativamente y el índice de grasa corporal disminuyó significativamente después de la intervención nutricional. Los biomarcadores analizados tuvieron un impacto positivo, con la excepción de la concentración de nitrógeno ureico que mostró una tendencia a aumentar después de la intervención nutricional, efecto que puede estar relacionado con el aumento proporcional de la ingesta de proteínas. Conclusión: La propuesta de intervención nutricional presentó impactos positivos en el metabolismo energético de los esquiadores, impactando directamente en la recuperación de la fatiga deportiva de los atletas. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.


Assuntos
Humanos , Masculino , Adulto Jovem , Esqui/fisiologia , Fadiga Muscular/fisiologia , Terapia Nutricional/métodos , Desempenho Atlético/fisiologia , Recomendações Nutricionais
6.
J Musculoskelet Neuronal Interact ; 22(4): 504-513, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36458388

RESUMO

OBJECTIVES: Females tend to fatigue less than males after isometric exercise, but less is clear for isotonic exercise. Further, there have been relatively few sex comparisons for fatigability of the plantar flexors (PFs). We sought to investigate potential sex differences in contractile properties after a sustained maximal voluntary isometric contraction (MVIC) and isotonic contractions. METHODS: Twenty-seven physically active males (n=14; 22±2 yrs) and females (n=13; 21±2 yrs) randomly performed a 2 min MVIC and 120 concentric isotonic (30% MVIC) contractions for the PFs on separate visits. Before and after each fatiguing task, muscle activation was obtained from brief MVICs, which was followed (~2 sec) by tibial nerve stimulation at rest. Contractile properties including peak twitch, absolute and normalized time to peak twitch, and half relaxation time were calculated. RESULTS: No sex differences existed for fatigue-induced changes in muscle activation (p=0.09-0.41; d=0.33-0.69) or contractile properties (p=0.19-0.96; d=0.06-0.94). CONCLUSIONS: Peripheral fatigue, as indicated by contractile parameters, did not differ between sexes after isometric or isotonic exercise. The PFs similar fiber type proportions between sexes or greater fiber type heterogeneity may explain why sex differences in fatigability, though common in other muscle groups (e.g., knee extensors), were not expressed in this muscle group.


Assuntos
Contração Muscular , Fadiga Muscular , Feminino , Humanos , Masculino , Terapia por Exercício , Contração Isométrica , Caracteres Sexuais , Adolescente , Adulto Jovem , Adulto
7.
PLoS One ; 17(12): e0276921, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36454887

RESUMO

BACKGROUND: Muscle fatigue is a crucial indicator to determine whether training is in place and to protect trainers. PURPOSE: To make full use of morphological information of surface EMG and ECG signals in the time domain, a new idea and method for the fatigue assessment of exercise muscles based on data fusion is proposed in this paper. METHODS: sEMG and ECG time series with the same length were obtained by signal preprocessing and sequence normalization, feature extraction of sequence tenses was realized by a deep learning network based on sequential convolution and signal fusion model of muscle fatigue evaluation was established by D-S evidence theory. EXPERIMENT: Thirty volunteers were recruited and divided into three groups. ECG signals and sEMG signals at the biceps brachii of the right upper limb were monitored in a 20-minute exercise cycle. RESULTS: The prediction result of TCN based on time domain signal is better than the commonly used KNN and SVM recognition algorithm, and the recognition accuracy of relaxed, excessive and fatigue by D-S fusion was 89%, 86%, 88.5%. The accuracy was 0.9055, 0.9494 and 0.9269, respectively. The recall rates of the three conditions were 0.9303, 0.9570 and 0.9435. The F-score of the three conditions was 0.8911, 0.8764 and 0.8837, respectively. CONCLUSION: Based on time series and time series convolutional network, sEMG and ECG fusion of motor muscle recognition method can better distinguish different state information and has certain practical value in the fields of muscle evaluation, clinical diagnosis, wearable devices and so on.


Assuntos
Exercício Físico , Fadiga Muscular , Humanos , Eletromiografia , Fatores de Tempo , Eletrocardiografia
8.
Medicina (Kaunas) ; 58(12)2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36556911

RESUMO

Background and Objectives: Verbal encouragement (VE) can be used to enhance performance in several sports, even though no studies have been conducted among swimmers and only a few effects have been reported in elite athletes. Besides influencing motor performance, VE is also known to enhance the physical load, thus potentially increasing the probability of developing fatigue. With this in mind, this study aimed to explore the effects of VE in swimmers in order to fill in the knowledge gap concerning the aquatic environment. Materials and Methods: Each athlete swam a maximal 200 m freestyle trial under two different conditions: one trial with VE and the other without VE. The two main outcome measures were: (1) performance velocity (m/s); and (2) muscle fatigue, investigated by means of surface electromyography. Sixty swimmers were recruited, aged 18.63 ± 3.46 years (median 18 years), 28 men (47%), and 32 women (53%), with 7.03 ± 3.9 years of experience. Results: With VE, performance significantly improved in the swim trial (p < 0.001, effect size (ES) -0.95, large). When breaking the results down into the first half (first (0-100 m) vs. the second half (100-200 m)), the ES was large in the first part (-1.11), indicating an improvement in performance. This worsened, however, in the second part of the trial (ES 0.63). In the multivariate analysis, years of experience were found to be a significant predictor of the change in overall performance (p = 0.011). There was a significant increase in muscle fatigue induced by VE, overall, and during the second half, but not during the first half of the trial. Conclusions: The present study indicates that VE during a middle-distance event (200 m) increases performance most in swimmers with little experience. However, it has a negative impact on fatigue.


Assuntos
Desempenho Atlético , Fadiga Muscular , Masculino , Humanos , Feminino , Desempenho Atlético/fisiologia , Natação/fisiologia , Atletas , Eletromiografia
9.
Respir Res ; 23(1): 357, 2022 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-36528761

RESUMO

BACKGROUND: Rapid magnetic stimulation (RMS) of the phrenic nerves may serve to attenuate diaphragm atrophy during mechanical ventilation. With different coil shapes and stimulation location, inspiratory responses and side-effects may differ. This study aimed to compare the inspiratory and sensory responses of three different RMS-coils either used bilaterally on the neck or on the chest, and to determine if ventilation over 10 min can be achieved without muscle fatigue and coils overheating. METHODS: Healthy participants underwent bilateral anterior 1-s RMS on the neck (RMSBAMPS) (N = 14) with three different pairs of magnetic coils (parabolic, D-shape, butterfly) at 15, 20, 25 and 30 Hz stimulator-frequency and 20% stimulator-output with + 10% increments. The D-shape coil with individual optimal stimulation settings was then used to ventilate participants (N = 11) for up to 10 min. Anterior RMS on the chest (RMSaMS) (N = 8) was conducted on an optional visit. Airflow was assessed via pneumotach and transdiaphragmatic pressure via oesophageal and gastric balloon catheters. Perception of air hunger, pain, discomfort and paresthesia were measured with a numerical scale. RESULTS: Inspiration was induced via RMSBAMPS in 86% of participants with all coils and via RMSaMS in only one participant with the parabolic coil. All coils produced similar inspiratory and sensory responses during RMSBAMPS with the butterfly coil needing higher stimulator-output, which resulted in significantly larger discomfort ratings at maximal inspiratory responses. Ten of 11 participants achieved 10 min of ventilation without decreases in minute ventilation (15.7 ± 4.6 L/min). CONCLUSIONS: RMSBAMPS was more effective than RMSaMS, and could temporarily ventilate humans seemingly without development of muscular fatigue. Trial registration This study was registered on clinicaltrials.gov (NCT04176744).


Assuntos
Nervo Frênico , Respiração Artificial , Humanos , Diafragma/fisiologia , Fenômenos Magnéticos , Fadiga Muscular/fisiologia , Nervo Frênico/fisiologia , Respiração Artificial/efeitos adversos
10.
Artigo em Inglês | MEDLINE | ID: mdl-36554889

RESUMO

This study focused on the effect of acute Judo training on countermovement jump (CMJ) performance and perceived fatigue among a group of highly trained collegiate judo athletes. Twenty male judo athletes participated in this study (age: 20.65 ± 1.22 years, weight: 84.17 ± 28.45 kg). Participants were assessed for CMJperformance changes before, immediately after (0 h), 12 h after, and 24 h after judo training (JT) using unloaded CMJ(CMJunloaded) and loaded CMJ(CMJloaded). All the jumps were performed on a force plate, and the force-time curves were collected for further analysis. Respondents' perceptions were evaluated using the modified rating of perceived exertion (mRPE) before, after (0 h), 12 h, and 24 h after JT. CMJparameters were analyzed at four measured points using a one-way repeated analysis of variance. Effect sizes (ES) and percentage changes before versus 24 h after JT were calculated for comparison. Associations between the CMJparameters and mRPE were analyzed using the Pearson product-moment correlation. The ratio of flight time to contact time significantly decreased, whereas the eccentric duration, concentric duration, and total duration significantly increased (p < 0.05) in both CMJs 24 h after JT. Compared with CMJunloaded, CMJloaded had a significantly lower (p < 0.05) flight time, jump height, peak velocity, and peak power. The mRPE and CMJloaded peak velocity showed moderate- to high-level negative correlation results both 0 and 24 h after training (r = -0.543, p < 0.05; r = -0.479, p < 0.05). In this study, we only observed the effect of fatigue on the neuromuscular (NM) system 24 h after JT. CMJloaded height may help to better determine fatigue state compared with CMJunloaded. According to the results, the neuromuscular effects of fatigue were not observed until 24 h after a single high-intensity training. Therefore, when arranging high-intensity special training or strength and conditioning training, one should reduce the volume of training appropriately to avoid fatigue accumulation and reduce the risk of sports injuries.


Assuntos
Atletas , Artes Marciais , Humanos , Masculino , Adulto Jovem , Adulto , Fadiga Muscular , Fadiga , Força Muscular
11.
Sci Rep ; 12(1): 19484, 2022 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-36376467

RESUMO

Forward head posture (FHP) is a serious problem causing head and neck disability, but the characteristics of muscle activity during long-term postural maintenance are unclear. This study aimed to investigate a comparison of electromyography (EMG) activation properties and subjective fatigue between young adults with and without habitual FHP. In this study, we examined the changes in the spatial and temporal distribution patterns of muscle activity using high-density surface EMG (HD-SEMG) in addition to mean frequency, a conventional measure of muscle fatigue. Nineteen male participants were included in the study (FHP group (n = 9; age = 22.3 ± 1.5 years) and normal group (n = 10; age = 22.5 ± 1.4 years)). Participants held three head positions (e.g., forward, backward, and neutral positions) for a total of 30 min each, and the EMG activity of the trapezius pars descendens muscle during posture maintenance was measured by HD-SEMG. The root mean square (RMS), the modified entropy, and the correlation coefficient were calculated. Additionally, the visual analogue scale (VAS) was evaluated to assess subjective fatigue. The RMS, VAS, modified entropy, and correlation coefficients were significantly higher in the FHP group than in the normal group (p < 0.001). With increasing postural maintenance time, the modified entropy and correlation coefficient values significantly decreased, and the mean frequency and VAS values significantly increased (p < 0.001). Furthermore, the forward position had significantly higher RMS, correlation coefficient, modified entropy, and VAS values than in the neutral position (p < 0.001). The HD-SEMG potential distribution patterns in the FHP group showed less heterogeneity and greater muscle activity in the entire muscle and subjective fatigue than those in the normal group. Excess muscle activity even in the neutral/comfortable position in the FHP group could potentially be a mechanism of neuromuscular conditions in this population.


Assuntos
Músculos Superficiais do Dorso , Humanos , Adulto Jovem , Masculino , Adulto , Músculos Superficiais do Dorso/fisiologia , Postura/fisiologia , Eletromiografia , Fadiga Muscular/fisiologia , Cabeça/fisiologia , Músculo Esquelético/fisiologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-36360770

RESUMO

Muscles are affected at the cellular level by exercised-induced fatigue, inducing changes in their stiffness. Examining muscle stiffness can improve the knowledge of various pathologic conditions, such as pain and injury. The objective of this study was to examine the stiffness of the medial gastrocnemius (MG) muscle and the lateral gastrocnemius (LG) muscle to determine the changes in stiffness, and to assess the differences in the stiffness between the MG and the LG, as affected by muscle fatigue measured using shear wave elastography (SWE) and a MyotonPRO after inducing muscle fatigue. A total of 35 healthy young adults participated in the study. The stiffness of the MG and the LG were assessed before and after a muscle fatigue protocol (MFP), which included three sets of 50 eccentric contractions of the calf muscles of the dominant leg, at rest, and at maximum voluntary contraction (MVC). The measurements were taken with SWE and the MyotonPRO simultaneously. Compared to baseline, the resting stiffness of the MG and the LG significantly increased immediately, 24 h, and 48 h after muscle fatigue (p < 0.05); however, during MVC, the stiffness of the MG decreased (p < 0.05) and that of the LG showed no change (p > 0.05). When the stiffness of the MG and the LG were compared before and after the MFP, changes in the stiffness of the MG were significantly greater than those in the LG (p < 0.05). This signifies that the MG was more affected by the exercise-induced muscle fatigue than was the LG. The assessment of musculoskeletal tissue and its characteristics, before and after eccentric exercise, is crucial in the prevention of overuse injuries associated with repeated exposure to both low and high levels of force.


Assuntos
Técnicas de Imagem por Elasticidade , Fadiga Muscular , Adulto Jovem , Humanos , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Perna (Membro) , Exercício Físico
13.
Medicine (Baltimore) ; 101(43): e31004, 2022 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-36316875

RESUMO

BACKGROUND: Fatigue is a common phenomenon encountered by athletes in ordinary life and sports. Fatigue results in decreased muscle strength, balance, agility, and an increased risk of injury, which together results in hampered sports performance. Several studies have examined the effects of Kinesio Tape (KT) application on muscle fatigue however, contradictory findings are reported. This study aimed to examine the effects of the application of KT on calf muscle fatigability. METHODS: A three-arm parallel pretest-post-test experimental design was used. Forty-five collegiate female athletes (mean age of 20.57 years) were randomly assigned to three groups. For the experimental group, KT with 50% tension; for the sham group, KT without any tension; and for the placebo group, rigid tape without any tension was applied. The number of heel rises (HRn) was measured before and after taping in the three groups, using Haberometer and Metronome. The tapes were applied in the Y shape to the calf muscle region. RESULTS: In the experimental group: The HRn significantly increased by 18.76 % (P = .000) after applying KT. In the sham and placebo groups: There was no change in HRn before and after Taping (P > .05). CONCLUSION: Y-shaped application of KT with 50% tension over the calf muscle region is effective in reducing its fatigability.


Assuntos
Fita Atlética , Adulto , Feminino , Humanos , Adulto Jovem , Atletas , Fadiga Muscular/fisiologia , Músculo Esquelético
14.
Am J Physiol Cell Physiol ; 323(6): C1642-C1651, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36317798

RESUMO

Low-frequency fatigue (LFF) is defined by a relatively larger deficit in isometric force elicited by low-frequency electrical stimulation compared with high-frequency stimulation. However, the effects of LFF on power during dynamic contractions elicited at low and high frequencies have not been thoroughly characterized. In the current study, rat soleus muscles underwent fatiguing either concentric, eccentric, or isometric contractions. Before and 1 h after the fatiguing contractions, a series of brief isometric and dynamic contractions elicited at 20 and 80 Hz stimulation to establish force-velocity relationships. Maximal force (Fmax), velocity (Vmax), and power (Pmax) were assessed for each frequency. Sarcoplasmic reticulum (SR) Ca2+ release and reuptake rates were assessed pre- and postfatigue. Prolonged fatigue was observed as a loss of Fmax and Pmax in muscles fatigued by concentric or eccentric, but not by isometric contractions. When quantified as a decrease in the ratio between 20 Hz and 80 Hz contractile output, LFF was more pronounced for isometric force than for power (-21% vs. -16% for concentrically fatigued muscles, P = 0.003; 29 vs. 13% for eccentrically fatigued muscles, P < 0.001). No changes in SR Ca2+ release or reuptake rates were observed. We conclude that LFF is less pronounced when expressed in terms of power deficits than when expressed in terms of force deficits, and that LFF, therefore, likely affects performance to a lesser degree during fast concentric contractions than during static or slow contractions.


Assuntos
Contração Isométrica , Fadiga Muscular , Ratos , Animais , Fadiga Muscular/fisiologia , Contração Isométrica/fisiologia , Músculo Esquelético/fisiologia , Contração Muscular/fisiologia , Estimulação Elétrica , Fadiga
15.
J Vis Exp ; (189)2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36440840

RESUMO

Execution of Sit-to-Stand (SitTS) in incomplete spinal cord injury (SCI) patients involves motor function in both upper and lower extremities. The use of arm support, in particular, is a significant assistive factor while executing SitTS movement in SCI population. In addition, the application of functional electrical stimulation (FES) onto quadriceps and gluteus maximus muscles is one of the prescribed management for incomplete SCI to improve muscle action for simple lower limb movements. However, the relative contribution of upper and lower extremities during SitTS has not been thoroughly investigated. Two motor incomplete SCI paraplegics performed repetitive SitTS to fatigue exercise challenge. Their performance was investigated as a mixed-method case-control study comparing SitTS with and without the assistance of FES. Three sets of SitTS tests were completed with 5-min resting period allocated in between sets, with mechanomyography (MMG) sensors attached over the rectus femoris muscles bilaterally. The exercise was separated into 2 sessions; Day 1 for voluntary SitTS and Day 2 for FES-assisted SitTS. Questionnaires were conducted after every session to gather the participants' input about their repetitive SitTS experience. The analysis confirmed that a SitTS cycle could be divided into three phases; Phase 1 (Preparation to stand), Phase 2 (Seat-off), and Phase 3 (Initiation of hip extension), which contributed to 23% ± 7%, 16% ± 4% and 61% ± 6% of the SitTS cycle, respectively. The contribution of arms and legs during SitTS movement varied in different participants based on their legs' Medical Research Council (MRC) muscle grade. In particular, the applied arm forces start to increase clearly when the leg forces start to decline during standing. This finding is supported by the significantly reduced MMG signal indicating leg muscle fatigue and their reported feeling of tiredness.


Assuntos
Perna (Membro) , Traumatismos da Medula Espinal , Humanos , Perna (Membro)/fisiologia , Braço/fisiologia , Projetos Piloto , Estudos de Casos e Controles , Fadiga Muscular/fisiologia
16.
Sportverletz Sportschaden ; 36(4): 178-187, 2022 12.
Artigo em Alemão | MEDLINE | ID: mdl-36446547

RESUMO

Although numerous studies have been performed, there are no clear findings providing a meaningful statement about how foot strike changes as a result of muscular fatigue. In studies on running fatigue, it is not possible to differentiate which kinematic or kinetic changes are a direct result of local muscle fatigue and varied speeds. This study aimed to investigate the effect of foot strike technique and localized muscle fatigue of the plantar and dorsal flexors on plantar pressure distribution and selected kinematic features of treadmill running. Twenty-six voluntary forefoot and rearfoot runners of similar age and body mass participated in the study. Each group completed two tests with a time interval of 3-7 days. The kinematic data was measured with the help of a three-dimensional measuring and analysis system while the volunteers ran on the treadmill. The fatigue protocol included an isometric maximal force test and an isokinetic endurance test. In order to check the differences, a variance analysis with repeated measurements was used. The strength values of the two groups of runners showed significant average differences in the plantar flexors in the endurance test and in the fatigue index for both the left and right legs. The results of the strength values are surprising because the plantar flexors of this group of runners should be well-trained due to the forefoot strike during regular running. In response to fatigue, the pressure maxima decreased under the exposed foot regions, i.e. under the forefoot at forefoot strike and under the heel at rearfoot strike. The two groups of runners differed in foot angle at foot-on with higher values measured in the forefoot runners. The larger foot angle of the forefoot runners improved shock absorption and can thus reduce the risk of injury.


Assuntos
, Fadiga Muscular , Humanos , Fenômenos Biomecânicos , Extremidade Inferior , Caminhada
17.
Artigo em Inglês | MEDLINE | ID: mdl-36429363

RESUMO

The aim of this study was to analyse the influence of fatigue on sprint biomechanics. Fifty-one football players performed twelve maximal 30 m sprints with 20 s recovery between each sprint. Sprint kinetics were computed from running speed data and a high-frequency camera (240 Hz) was used to study kinematic data. A cluster analysis (K-mean clustering) was conducted to classify individual kinematic adaptations. A large decrease in maximal power output and less efficiency in horizontally orienting the ground reaction force were observed in fatigued participants. In addition, individual changes in kinematic components were observed, and, according to the cluster analysis, five clusters were identified. Changes in trunk, knee, and hip angles led to an overall theoretical increase in hamstring strain for some players (Cluster 5, 20/51) but to an overall decrease for some others (Cluster 1, 11/51). This study showed that the repeated sprint ability (RSA) protocol had an impact on both kinetics and kinematics. Moreover, fatigue affected the kinematics in a different way for each player, and these individual changes were associated with either higher or lower hamstring length and thus strain.


Assuntos
Desempenho Atlético , Futebol Americano , Futebol , Humanos , Fenômenos Biomecânicos , Fadiga Muscular
18.
Artigo em Inglês | MEDLINE | ID: mdl-36429786

RESUMO

The straight-line run is the most frequent action in soccer goal scoring situations, and it deserves considerable attention. The objective of this study was to evaluate the neuromuscular fatigue produced by an independent repeat sprint ability (RSA) test, a countermovement jump (CMJ) and a hamstring test (HT) in elite female soccer players. Twenty-four elite female soccer players participated in the study. The evaluation protocol included hamstring and CMJ tests before an RSA test (6 × 40 m 30 s rest), and hamstring and CMJ post-tests. Significant differences were found between pre-post HT measurements in the maximum angulation of the right leg (p = 0.012 Effect Size (ES) = 0.27), and the maximum velocity was higher in the left leg after RSA (p = 0.023 ES = 0.34). CMJ height after RSA was significantly lower than before the RSA test (p < 0.001 ES = 0.40). The sprint total time (SprintTT) and percentage difference (%Dif) increased throughout the RSA (p < 0.001, and ES = 0.648 and ES = 0.515, respectively). In elite female soccer players, it seems that the fatigue induced by an RSA test can be assessed through the loss of CMJ height and the different performance variables extracted from the RSA itself (e.g., SprintTT, Ideal Sprint). These findings could contribute to better performance management and injury prevention for elite female soccer players.


Assuntos
Desempenho Atlético , Músculos Isquiossurais , Corrida , Futebol , Feminino , Humanos , Fadiga Muscular
19.
Artigo em Inglês | MEDLINE | ID: mdl-36429882

RESUMO

Manual materials handling (MMH) contributes to musculoskeletal disorders (MSDs) in the workplace. The development and recovery of muscle fatigue are essential in work/rest arrangements for MMH tasks. A pulling experiment, including a muscle fatigue test and a muscle fatigue recovery test, was conducted. In the muscle fatigue test, the participant performed a pulling task on a treadmill with a walking velocity of 1 km/h until they could no longer do so. The load was either 30 or 45 kg. The maximum endurance time (MET) was recorded. The pull strength (PS) of the participant both before and after the pulling task was measured. The subjective ratings of muscle fatigue after the pulling task were recorded. In the muscle fatigue recovery test, the participant took a rest after performing the pulling task. The participants reported their subjective ratings of muscle fatigue on the CR-10 scale after taking a rest for a time period t, where t = 1, 2,…, 6 min. The PS of the participant was then measured again. It was found that the load significantly affected the MET for pulling tasks. The load was insignificant to the decrease of the PS, but was significant to the decrease rate (PS decrease per min) of the PS. The PS decrease rate for the 45 kg condition (30.8 ± 16.5 N/min) was significantly higher (p < 0.05) than that of the 30 kg condition (15.4 ± 5.5 N/min). The recovery time significantly affected the PS and CR-10. Two MET models were established to explore the development of muscle fatigue in pulling tasks. A PS model was constructed to describe the recovery of muscle force. A CR-10 model was proposed to show the subjective ratings of recovery. These models are beneficial for determining the work/rest allowance for pulling tasks.


Assuntos
Fadiga Muscular , Músculo Esquelético , Humanos , Fadiga Muscular/fisiologia , Músculo Esquelético/fisiologia , Caminhada/fisiologia , Teste de Esforço , Local de Trabalho
20.
Artigo em Inglês | MEDLINE | ID: mdl-36430106

RESUMO

How the match-derived load metrics relate to post-match fatigue in soccer is scarcely researched. Thus, the aim of this study was to determine the associations between soccer match-related internal and external loads, neuromuscular performance decrease and intermittent-running endurance capacity decrement immediately post-match. Vertical jump (countermovement jump), straight-line sprinting (10- and 20-m sprint), change of direction ability (T-test) and intermittent-running endurance capacity (YO-YO intermittent recovery level 2) were measured one day before and immediately after a friendly match in male soccer players. During the match, players' internal and external loads were also monitored, including heart rate-derived indices, total distance at various speed thresholds, average running velocity, maximal running velocity, number of sprints and number of accelerations and decelerations at various intensity thresholds. The results show that match-induced fatigue was reflected on neuromuscular performance and intermittent-running endurance capacity immediately post-match (p < 0.05). The quantification of percentage change of match external-load metrics, particularly accelerations and decelerations, provides a useful non-invasive predictor of subsequent neuromuscular fatigue status in soccer players immediately post-match (p < 0.05). However, only internal load metrics present a practical application for predicting intermittent-running endurance capacity impairment (p < 0.05). In summary, internal and external load metrics may allow for predicting the extent of acute fatigue, and variability between halves may represent a valuable alternative to facilitate the analysis of match-related fatigue both for research and applied purposes.


Assuntos
Corrida , Futebol , Masculino , Humanos , Fadiga Muscular , Aceleração , Estado Nutricional
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