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The nervous system controls eccentric exercise in a special way. During eccentric exercise, excitability increases in cortex, and inhibition decreases, causing excitability decrease in spinal cords. In another hand, increased cortical excitability results in extra excitatory compensation for spinal inhibition. The excitability of the corticospinal pathway depends on the balance between excitability and inhibition of the spinal cord level finally, which usually decreases. Many factors, such as the intensity of contraction, can affect the balance of corticospinal excitability. There is a cross-over effect in eccentric exercise, which promotes corticospinal excitability in untrained limbs. However, the effects and mechanisms of muscle length, fatigue and training duration are still unclear, and current researches have focused in the healthy populations. More researches are needed to explore the effects of eccentric exercise on ill populations.
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ABSTRACT Introduction: Muscle microlesions produced by eccentric contractions (EC) cause changes in strength, endurance, power and neuromuscular activity parameters for an extended period of time. Objectives: To investigate the effect of aquatic exercise after EC-induced muscle injury on strength, endurance, power and neuromuscular activity parameters. Methods: A cross-sectional experimental study with six subjects (age 25 ± 4 years, weight 77 ± 4kg and height of 162 ± 2 cm) with EC-induced muscle injury followed up during a recovery period (48h, 72h and 96h) without intervention (Group 1A) and involving aquatic exercises (Group 1B). Dynamic and isometric strength, muscular endurance, and vertical/horizontal power tests as well as vastus lateralis neuromuscular activity measurements were performed before, immediately after, and during the recovery period. Results: Our results indicate that the intervention in Group 1B, when compared to Group 1A, accelerated the recovery of dynamic (p <0.01) and isometric (p <0.03) strength at 48h and 72h, increased vertical power at 48h (p <0.05) and horizontal power at 48h and 72h (p <0.05), and reduced neuromuscular activity (p <0.05) at 48h and 72h after EC. Conclusions: According to our findings, performing aquatic exercises during the recovery period improves muscle efficiency and accelerates strength, power and neuromuscular activity recovery. Level of evidence l; Randomized clinical trial.
RESUMO Introdução: As microlesões musculares geradas por contrações excêntricas (CE) provocam alterações dos parâmetros de força, resistência, potência e atividade neuromuscular por período prolongado. Objetivos: Investigar o efeito do exercício aquático depois de lesão muscular provocada por CE sobre os parâmetros força, resistência, potência e atividade neuromuscular. Métodos: Estudo experimental cruzado com seis indivíduos (idade 25 ± 4 anos, peso 77 ± 4 kg e altura 162 ± 2 cm) com lesão muscular por CE e acompanhados durante um período de recuperação (48 h, 72 h e 96 h) sem intervenção (Grupo 1A) e envolvendo exercícios aquáticos (Grupo 1B). Antes, imediatamente e durante o período de recuperação foram realizados testes de força dinâmica, isométrica, resistência muscular, potência vertical/horizontal e mensuração da atividade neuromuscular do músculo vasto lateral. Resultados: Nossos resultados apontam que a intervenção no Grupo 1B, em comparação com o Grupo 1A, acelerou a recuperação da força dinâmica (p < 0,01) e isométrica (p < 0,03) nos tempos de 48 h e 72 h, aumentou a potência vertical no tempo de 48 h (p < 0,05) e a horizontal nos tempos de 48 h e 72 h (p < 0,05) e reduziu a atividade neuromuscular (p < 0,05) nos tempos de 48 h e 72 h depois de CE. Conclusões: De acordo com nossos achados, apontamos que os exercícios aquáticos durante o período de recuperação melhoram a eficiência muscular e aceleram a recuperação de força, potência e atividade neuromuscular. Nível de evidência l; Estudo clínico randomizado
RESUMEN Introducción: Las microlesiones musculares generadas por contracciones excéntricas (CE) provocan alteraciones de los parámetros de fuerza, resistencia, potencia y actividad neuromuscular por período prolongado. Objetivos: Investigar el efecto del ejercicio acuático después de una lesión muscular provocada por CE sobre los parámetros fuerza, resistencia, potencia y actividad neuromuscular. Métodos: Estudio experimental cruzado con seis individuos (edad 25±4 años, peso 77±4kg y altura 162±2cm) con lesión muscular por CE y acompañados durante un período de recuperación (48h, 72h y 96h) sin intervención (Grupo 1A) e involucrando ejercicios acuáticos (Grupo 1B). Antes, inmediatamente después y durante el período de recuperación, fueron realizados tests de fuerza dinámica, isométrica, resistencia muscular, potencia vertical/horizontal y medición de la actividad neuromuscular del músculo vasto lateral. Resultados: Nuestros resultados apuntan que la intervención en el Grupo 1B, en comparación con el Grupo 1A, aceleró la recuperación de la fuerza dinámica (p<0,01) e isométrica (p<0,03) en 48h y 72h, aumentó la potencia vertical en el tiempo de 48h (p<0,05) y la horizontal en los tiempos de 48h y 72h (p<0,05) y redujo la actividad neuromuscular (p<0,05) en los tiempos de 48h y 72h después de la CE. Conclusiones: De acuerdo con nuestros hallazgos, apuntamos que los ejercicios acuáticos durante el período de recuperación mejoran la eficiencia muscular y aceleran la recuperación de fuerza, potencia y actividad neuromuscular. Nivel de evidencia l; Estudio ensayo clínico aleatorizado.
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Objetivo: determinar el efecto de la inmersión en agua fría sobre los marcadores de daño muscular inducidos por el ejercicio excéntrico. Metodología: estudio cuasi-experimental, con 15 hombres nadadores, 10 en el grupo de tratamiento y 5 en el grupo control. Luego del protocolo excéntrico, con 2 series de 10 repeticiones en extensión de rodilla, el grupo de tratamiento tuvo 15 minutos de inmersión en agua fría, a 15 °C ± 1 °C, y el grupo control tuvo 15 minutos de inmersión en agua termoneutra, a 32 °C ± 1 °C. Las variables (CK, LDH, salto vertical, potencia y percepción del dolor) se registraron a las 24, 48 y 72 horas posteriores a la intervención. Resultados: la inmersión en agua fría no tiene efectos estadísticamente significativos en la reducción de los marcadores de daño muscular.
Objective: To determine the effect of immersion in cold water on markers of muscle damage induced by eccentric exercise. Methodology: Quasi-experimental study, with 15 male swimmers, 10 in the treatment group and 5 in the control group. After the eccentric protocol, with 2 series of 10 repetitions in knee extension, the treatment group had 15 minutes of immersion in cold water, at 15 °C ± 1 °C, and the control group had 15 minutes of immersion in thermoneutral water, at 32 °C ± 1 °C. The variables (CK, LDH, vertical jump, power and pain perception) were recorded at 24, 48 and 72 hours after the intervention. Results: Immersion in cold water has no statistically significant effects in reducing markers of muscle damage.
Objetivo: Determinar o efeito da imersão em água fria sobre os marcadores de dano muscular induzido por exercício excêntrico. Metodologia: Estudo quase experimental, 15 homens nadadores, 10 no grupo de tratamento e 5 no grupo de controle. Após o protocolo excêntrico (2 séries de 10 repetições na extensão do joelho), o grupo de tratamento teve 15 minutos de imersão em água fria a 15 ° C ± 1 ° C e o grupo controle teve 15 minutos de imersão em água termo-neutra a 32 ° C ± 1 ° C. As variáveis (CK, LDH, salto vertical, potência e percepção da dor) foram registradas nas 24, 48 e 72 horas após a intervenção. Resultados: A imersão em água fria não tem efeitos estatisticamente significativos na redução dos marcadores de dano muscular.
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Swimming , Water , Exercise , Wounds and InjuriesABSTRACT
This article introduced the characteristics of eccentric contraction and its mechanism,as well as its application in the re-habilitation of chronic heart disease,chronic obstructive pulmonary disease,sports injuries,elderly sarcopenia,anterior cruciate ligament repair,cancer survivor,type 2 diabetes and nervous system diseases,etc.
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<p><b>PURPOSE</b>Macrophages are known to be important for healing numerous injured tissues depending on their functional phenotypes in response to different stimuli. The objective of this study was to reveal macrophage phenotypic changes involved in exercise-induced skeletal muscle injury and regeneration.</p><p><b>METHODS</b>Adult male Sprague-Dawley rats experienced one session of downhill running (16° decline, 16 m/min) for 90 min. After exercise the blood and soleus muscles were collected at 0 h, 6 h, 12 h, 1 d, 2 d, 3 d, 1 w and 2 w after exercise, separately.</p><p><b>RESULTS</b>It was showed that CD68 M1 macrophages mainly infiltrated into muscle necrotic sites at 1-3 d, while CD163 M2 macrophages were present in muscles from 0 h to 2 weeks after exercise. Using transmission electron microscopy, we observed activated satellite cells 1 d after exercise. Th1-associated transcripts of iNOS and Ccl2 were inhibited post exercise, while COX-2 mRNA was dramatically increased 12 h after running (p < 0.01). M2 phenotype marker Arg-1 increased 12 h and 3 d (p < 0.05, p < 0.01) after exercise, and Clec10a and Mrc2 were up-regulated in muscles 12 h following exercise (p < 0.05, p < 0.05).</p><p><b>CONCLUSION</b>The data demonstrate the dynamic patterns of macrophage phenotype in skeletal muscle upon eccentric exercise stimuli, and M1 and M2 phenotypes perform different functions during exercise-induced skeletal muscle injury and recovery.</p>
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Animals , Male , Rats , Antigens, CD , Antigens, Differentiation, Myelomonocytic , Macrophages , Physiology , Muscle, Skeletal , Wounds and Injuries , Pathology , Myoglobin , Blood , Phenotype , Physical Conditioning, Animal , Rats, Sprague-Dawley , Receptors, Cell SurfaceABSTRACT
Background and Objectives: Resistance training in the form of concentric and eccentric exercise is a highly recommended form of exercise for athletes and an individual with or at risk of cardiovascular diseases. So the purpose of this study was to compare the effect of exercise intensity on cardiovascular changes during concentric and eccentric resistive knee extension exercise on healthy males. Methods: A sample of 50 healthy subjects between the age group (18-25 years) were randomly selected and divided into 2 groups, A (concentric exercise) and B (Eccentric exercise). Each group exercised knee extension at 3 different intensities 75% of 1 RM, 85% of 1 RM, 1 RM). 5 minutes warm up was given and 5 minute rest was given after each exercise. SBP, DBP, HR, MAP and RPP were measured before and after each exercise. Results: Statistical analysis done with related t-test and unrelated t-test. Both the group improved but significantly more improvement was seen in concentric group when compared to eccentric group. Conclusion: The result of the study suggests that eccentric exercise produce lower cardiovascular response than concentric exercise.
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Objective From the angle of skeletal muscle ultrastructure and free radical metabolism,the paper explored the effect of vitamin E on skeletal muscle's damage after eccentric exercise.Methods 48 male Sprague Dawley rats were randomly divided into the control group,the sport group,the physiological saline group,and the vitamin E group.The model of animals was made by a bout of eccentric exercise on a treadmill.After the training,triceps brachiies were extracted from the right side of rats.Parts of triceps brachiies were made for microelectric slices,the others for the extracting of SR by the method of centrifugation at different speeds and for measuring the content of MDA and activity of SOD.Results In the vitamin E group,the muscular ultrastructures damage were improved obviously compared with that of the physiological saline group.Meanwhile,the value of MDA in the vitamin E group was greatly decreased and activity of SOD was notably increased compared with the sport group and the physiological saline group,but still worse than those of the control group.Conclusions Supplying of vitamin E could decrease the content of MDA in SR of skeletal muscle,increase the activity of SOD,then further relieve the effect of free radical on athletic injury.
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Objective To explore the effect of wrist extensor energy on humeral epicondylitis. Methods 48 humeral epicondylitis pa-tients were divided into muscular energy group and block therapy group with 24 cases in each group. The muscular energy group was treat-ed with muscle energy technique, and the other group received block therapy. They were assessed with Visual Analogue Scale (VAS) and muscle strength. They were followed up 3 months, 6 months and 1 year after discharge. Results The score of VAS was lower in the block therapy group than in the muscular energy group (P0.05);6 months after discharge, the muscular energy group (75.0%) was better than the block therapy group (46.1%) (P<0.01); 1 year after dis-charge, the muscular energy group (54.2%) was better than the block therapy group (16.7%) (P<0.01). Conclusion The block therapy is bet-ter in short-term effect on humeral epicondylitis, and the muscle energy technique was better in long-term effect.
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This study was conducted to investigate whether administration of IH901, a ginseng intestinal metabolite, ameliorates exercise-induced oxidative stress while preserving antioxidant defense capability in rat skeletal muscles and lung. Eight adult male Sprague-Dawley rats per group were randomly assigned to the resting control, exercise control, resting with IH901 (25, 50, and 100 mg/kg) consumption (R/IH901), or exercise with IH901 (25, 50, and 100 mg/kg) consumption (E/IH901) group. The trained groups ran 35 min 2 days/week for 8 weeks. To analyze the IH901-training interaction, serum biochemical analysis, lipid peroxidation, citrate synthase, protein oxidation, antioxidant and superoxide dismutase in skeletal muscles and lung tissue were measured. Compared to the exercise control group, animals that consumed IH901 had significantly increased exercise endurance times (p < 0.05) and decreased plasma creatine kinase and lactate dehydrogenase levels (p < 0.05), while those in the E/IH901 groups had increased citrate synthase and anti-oxidant enzymes and decreased lipid peroxidation and protein oxidation (p < 0.05). In conclusion, IH901 consumption in aging rats after eccentric exercise has beneficial effects on anti-inflammatory and anti-oxidant activities through down-regulation of pro-inflammatory mediators, lipid peroxidation, and protein oxidation and up-regulation of anti-oxidant enzymes.
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Animals , Male , Rats , Aging , Antioxidants/administration & dosage , Dose-Response Relationship, Drug , Lung/drug effects , Muscle, Skeletal/drug effects , Oxidative Stress/drug effects , Panax/chemistry , Physical Conditioning, Animal , Rats, Sprague-Dawley , Sapogenins/administration & dosage , Specific Pathogen-Free OrganismsABSTRACT
O objetivo deste estudo foi analisar a resposta inflamatória induzida por grande número de ações excêntricas (AE) máximas realizadas pelos flexores do cotovelo. Participaram do estudo nove homens jovens, que realizaram 35 séries de seis AE nos flexores de cotovelo, com intervalo de um minuto, utilizando um dinamômetro isocinético em uma velocidade de 210º.s-1. As variáveis mensuradas foram: a contração isométrica voluntaria máxima (CIVM), a amplitude de movimento (AM), a dor muscular de inicio tardio (DMIT), a interleucina-6 (IL-6) e o fator de necrose tumoral alfa (TNF-α). Alterações significantes foram observadas para os marcadores indiretos de dano muscular (CIVM, AM e DMIT), entretanto não houve modificações para os marcadores inflamatórios (IL-6 e TNF-α). Em conclusão, os resultados demonstraram que mesmo com alterações nos marcadores indiretos de dano muscular após a realização de um grande número de AE não foram observadas alterações na resposta inflamatória sistêmica.
The objective of this study was to analyze the magnitude of the inflammatory response induced by a high number of eccentric actions (AE) of the elbow flexors. Participated on this study nine young men who performed 35 sets of six AE of the elbow flexors, with an one minute interval, using an isokinetic dynamometer at 210º.s-1. Maximum voluntary isometric contraction (MVIC), range of motion (ROM), delayed onset muscle soreness (DOMS), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) were measured. Significant changes were observed for markers of muscle damage (MVIC, ROM and DOMS), however, there were no changes on inflammatory markers IL-6 and TNF-α. In conclusion, the results show that even with large numbers of AE and changes in indirect markers of muscle damage, no change was observed in the systemic inflammatory response.
El objetivo del presente estudio fue analizar la magnitud de la respuesta inflamatoria inducida por un gran número de acciones excéntricas (AE) de los flexores del codo. Han participado del estudio nueve jóvenes que llevaron a cabo 35 series de seis AE de los flexores del codo, con un intervalo de un minuto, utilizando un dinamómetro isocinético a 210º.s-1. Fueran mensurados la máxima contracción voluntaria isométrica (CIVM), la amplitud de movimiento (AM), el dolor muscular de aparición tardía (DMIT), la interleucina 6 (IL-6) y el factor de necrosis tumoral alfa (TNF-α). Se observaron cambios significativos para los marcadores de daño muscular (CIVM, AM y DMIT), sin embargo, no hubo cambios en los marcadores de inflamación IL-6 y TNF-α. En conclusión, los resultados indican que mismo con un gran número de AE y cambios en los marcadores indirectos de daño muscular, no se observaron cambios en la respuesta inflamatoria sistémica.
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Humans , Male , Young Adult , Cytokines , Elbow , Exercise , InflammationABSTRACT
Abstract The reduction of skeletal muscle loss in pathological states, such as muscle disuse, has considerable effects in terms of rehabilitation and quality of life. Since there is no currently effective and safe treatment available for skeletal muscle atrophy, the search for new alternatives is necessary. Resistance exercise (RE) seems to be an important tool in the treatment of disuse-induced skeletal muscle atrophy by promoting positive functional (strength and power) and structural (hypertrophy and phenotypic changes) adaptive responses. Human and animal studies using different types of resistance exercise (flywheel, vascular occlusion, dynamic, isometric, and eccentric) have obtained results of great importance. However, since RE is a complex phenomenon, lack of strict control of its variables (volume, frequency, intensity, muscle action, rest intervals) limits the interpretation of the impact of the manipulation on skeletal muscle remodeling and function under disuse. The aim of this review is to critically describe the functional and morphological role of resistance exercise in disuse-induced skeletal muscle atrophy with emphasis on the principles of training.
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Humans , Muscle Strength/physiology , Muscle, Skeletal/physiopathology , Muscular Atrophy/therapy , Resistance Training/adverse effects , Hypertrophy/therapyABSTRACT
Ankle and foot injuries are endemic to all sports that involve running, jumping, cutting, or kicking. Ankle injuries, especially ligament sprains are the most common injuries seen at all levels of athletic participation. Although many of ankle and foot injuries are well recovered after short-term conservative managements, there are not uncommon patients with chronic pain and dysfunction after acute injury because of improper diagnosis and rehabilitation. In this chapter, a brief review of functional anatomy, biomechanics, and clinical aspects are presented, followed by a special discussion of rehabilitation of various injuries that may involve the ankle and foot.
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Animals , Humans , Ankle , Ankle Injuries , Athletic Injuries , Biomechanical Phenomena , Chronic Pain , Foot , Foot Injuries , Ligaments , Running , Sports , Sprains and StrainsABSTRACT
Ankle and foot injuries are endemic to all sports that involve running, jumping, cutting, or kicking. Ankle injuries, especially ligament sprains are the most common injuries seen at all levels of athletic participation. Although many of ankle and foot injuries are well recovered after short-term conservative managements, there are not uncommon patients with chronic pain and dysfunction after acute injury because of improper diagnosis and rehabilitation. In this chapter, a brief review of functional anatomy, biomechanics, and clinical aspects are presented, followed by a special discussion of rehabilitation of various injuries that may involve the ankle and foot.
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Animals , Humans , Ankle , Ankle Injuries , Athletic Injuries , Biomechanical Phenomena , Chronic Pain , Foot , Foot Injuries , Ligaments , Running , Sports , Sprains and StrainsABSTRACT
【Purpose】 To investigate effects of physiotherapy on delayed onset muscle soreness (DOMS), DOMS was induced in the elbow flexors of the non-dominant arm. We selected transcutaneous electrical nerve stimulation (TENS) to examine effects of physiotherapy to the recovery process.【Methods】 Fifteen human volunteers were recruited. DOMS was induced by eccentric exercise. Subjects were assigned randomly to one of three groups (Control, 110 Hz TENS, 4 Hz TENS). TENS was applied for 20 min over the biceps brachii on 1 day only after exercise. Measurements of Mechanical Pain Threshold (MPT) and Visual Analogue Scale (VAS) were performed as evaluation of pain. Measurements were taken before and after exercise.【Results】 There was no significant improvement in MPT and VAS among all three groups.【Conclusion】 It was suggested application of TENS on DOMS at the parameters used here had no beneficial effect.
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This study was designed to investigate the effects of supplementing soy peptide on isometric performances and serum CK and LDH trends after a high intensity eccentric exercise stress. Study subjects consisted of 13 males and were divided into 2 groups. They were instructed to take 4,000 mg of soy peptide or placebo orally before and for 7 days following the initial exercise stress. Soy peptide group revealed significantly faster improvements in knee extension performance at 72 hr-post the eccentric exercise (p<0.05). Comparing with placebo group, soy peptide group showed significantly lower serum LDH activity 168 hr after the exercise (p<0.05), while as to serum CK levels, significant difference was not observed between those 2 groups. These results indicate that oral supplementation of soy peptide could induce not only reduction in serum LDH activity level, but also faster recovering in isometric performance after high intensity repetitive eccentric exercise.
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Delayed Onset Muscle Soreness (DOMS) is characterized by a sensation of discomfort that usually develops 24-48 hours after unaccustomed exercise, with muscle swelling and stiffness that usually results in a reduced range of movement. Muscle weakness is often seen. It may be surmised that DOMS is a problem that affects all athletes.<BR>We examined six male subjects to determine the effect of acupuncture stimulation on DOMS, which was induced experimentally in both legs using a heel raising exercise. Acupuncture stimulation has long been used in the treatment of pain, but there is insufficient proof of its efficacy. A problem acupuncture research has had to face is the concept of a control group. To deal with this, we used non-invasive acupuncture stimulation, which would allow the simulation of the acupuncture procedure without penetrating the skin. The leg that would receive actual acupuncture stimulation and the leg that would receive non-invasive stimulation after the induction of DOMS were determined by randomization.<BR>The muscle stiffness, ankle range of movement, maximal voluntary contraction, one-legged vertical jump, muscle tenderness, pain on muscle stretching, pain on muscle contraction, ankle mobility and subjective muscle strain were measured as indices of stimulation efficacy. Pain on muscle stretching was significantly less (p<0.05) at 48 hours after exercise for the side stimulated by acupuncture as compared with the side stimulated non-invasively. The other indices did not differ significantly between the side stimulated using acupuncture stimulation and the side stimulated non invasively. These results suggest that the early relief of DOMS can be achieved by acupuncture stimulation.
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Objective Through morphometric methods,the effects of soy hydrolyzed peptides(SHPs) supplementation on histological and ultrastructural damages of skeletal muscle after intensive training were investigated.Methods 150 male Sprague-Dawley rats were randomly divided into 15 groups according to different supplementations(placebo,ISP and SHPs),exercise or not and different sampling phase after exercise.Rats in exercise groups ran 120 minutes at speed of 20?1m /min and-16? of slope.All rats were respectively fed with 2ml beverage containing 15% SHPs,15% ISP or placebo for 1 week before exercise.Results HE staining results showed that the skeletal muscle structure changed obviously in 24～48hr after exercise and the ultrastructure of skeletal muscle changed evidently in 12～24hr after exercise.With ISP or SHPs supplementation,the histological and ultrastructural damages of skeletal muscle reduced obviously.Moreover,SHPs supplementation showed better protective effects than ISP supplementation.