RESUMEN
Upper limb performance is affected by diabetes mellitus (DM). Neuromuscular junction (NMJ) is a key structure to understand the relationship between performance and morphology in DM. The aim of the study was to analyze NMJ plasticity due to DM in an animal model and its relationship with the function of forelimbs in rats. Twelve Wistar rats were divided into control (C) and DM groups. Animals were trained to perform a grasping task, following procedures of habituation, shaping, and reaching task. DM was induced using streptozotocin. Forelimb neuromuscular performance for dexterity was evaluated one day before DM induction and five weeks following induction. After that, biceps, triceps, and finger flexors and extensors were removed. Connective tissue and muscle fiber cross-sectional area (CSA) were measured. NMJ was assessed by its morphometric characteristics (area, perimeter, and maximum diameter), using ImageJ software. Motor performance analyses were made using single pellet retrieval task performance test. Student's t-test was used for comparisons between groups. A significant decrease in all NMJ morphometric parameters was observed in the DM group compared with the C group. Results showed that DM generated NMJ retraction in muscles involved in a reaching task. These alterations are related to signs of muscular atrophy and to poor reaching task performance. In conclusion, induced DM caused NMJ retraction and muscular atrophy in muscles involved in reaching task performance. Induced DM caused significantly lower motor performance, especially in the final moments of evaluation, when DM compromised the tropism of the muscular tissue.
Asunto(s)
Adaptación Fisiológica/fisiología , Diabetes Mellitus Experimental/patología , Unión Neuromuscular/patología , Análisis y Desempeño de Tareas , Animales , Diabetes Mellitus Experimental/fisiopatología , Masculino , Ratones , Unión Neuromuscular/fisiopatología , Ratas , Ratas WistarRESUMEN
Upper limb performance is affected by diabetes mellitus (DM). Neuromuscular junction (NMJ) is a key structure to understand the relationship between performance and morphology in DM. The aim of the study was to analyze NMJ plasticity due to DM in an animal model and its relationship with the function of forelimbs in rats. Twelve Wistar rats were divided into control (C) and DM groups. Animals were trained to perform a grasping task, following procedures of habituation, shaping, and reaching task. DM was induced using streptozotocin. Forelimb neuromuscular performance for dexterity was evaluated one day before DM induction and five weeks following induction. After that, biceps, triceps, and finger flexors and extensors were removed. Connective tissue and muscle fiber cross-sectional area (CSA) were measured. NMJ was assessed by its morphometric characteristics (area, perimeter, and maximum diameter), using ImageJ software. Motor performance analyses were made using single pellet retrieval task performance test. Student's t-test was used for comparisons between groups. A significant decrease in all NMJ morphometric parameters was observed in the DM group compared with the C group. Results showed that DM generated NMJ retraction in muscles involved in a reaching task. These alterations are related to signs of muscular atrophy and to poor reaching task performance. In conclusion, induced DM caused NMJ retraction and muscular atrophy in muscles involved in reaching task performance. Induced DM caused significantly lower motor performance, especially in the final moments of evaluation, when DM compromised the tropism of the muscular tissue.
Asunto(s)
Animales , Masculino , Conejos , Ratas , Análisis y Desempeño de Tareas , Adaptación Fisiológica/fisiología , Diabetes Mellitus Experimental/patología , Unión Neuromuscular/patología , Ratas Wistar , Diabetes Mellitus Experimental/fisiopatología , Unión Neuromuscular/fisiopatologíaRESUMEN
The aim of this study was to compare muscle strength in male subjects with type 2 diabetes mellitus (DM2) with and without low plasma testosterone levels and assess the relationship between muscle strength, testosterone levels, and proinflammatory cytokines. Males (75) aged between 18 and 65 years were divided into 3 groups: control group that did not have diabetes and had a normal testosterone plasma level (>250 ng/dL), DnormalTT group that had DM2 with normal testosterone levels, and the DlowTT group that had DM2 and low plasma testosterone levels (<250 ng/dL). The age (means±SD) of the groups was 48.4±10, 52.6±7, and 54.6±7 years, respectively. Isokinetic concentric and isometric torque of knee flexors and extensors were analyzed by an isokinetic dynamometer. Plasma testosterone and proinflammatory cytokine levels were determined by chemiluminescence and ELISA, respectively. Glycemic control was analyzed by glycated hemoglobin (HbA1C). In general, concentric and isometric torques were lower and tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1ß plasma levels were higher in the groups with diabetes than in controls. There was no correlation between testosterone level and knee torques or proinflammatory cytokines. Concentric and isometric knee flexion and extension torque were negatively correlated with TNF-α, IL-6, and HbA1C. IL-6 and TNF-α were positively correlated with HbA1C. The results of this study demonstrated that muscle strength was not associated with testosterone levels in men with DM2. Low muscle strength was associated with inflammatory markers and poor glycemic control.
Asunto(s)
Citocinas/sangre , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/fisiopatología , Fuerza Muscular/fisiología , Testosterona/sangre , Adolescente , Adulto , Anciano , Femenino , Humanos , Mediadores de Inflamación/sangre , Interleucina-6/sangre , Contracción Isométrica/fisiología , Rodilla , Masculino , Persona de Mediana Edad , Torque , Factor de Necrosis Tumoral alfa/sangre , Adulto JovenRESUMEN
The aim of this study was to compare muscle strength in male subjects with type 2 diabetes mellitus (DM2) with and without low plasma testosterone levels and assess the relationship between muscle strength, testosterone levels, and proinflammatory cytokines. Males (75) aged between 18 and 65 years were divided into 3 groups: control group that did not have diabetes and had a normal testosterone plasma level (>250 ng/dL), DnormalTT group that had DM2 with normal testosterone levels, and the DlowTT group that had DM2 and low plasma testosterone levels (<250 ng/dL). The age (means±SD) of the groups was 48.4±10, 52.6±7, and 54.6±7 years, respectively. Isokinetic concentric and isometric torque of knee flexors and extensors were analyzed by an isokinetic dynamometer. Plasma testosterone and proinflammatory cytokine levels were determined by chemiluminescence and ELISA, respectively. Glycemic control was analyzed by glycated hemoglobin (HbA1C). In general, concentric and isometric torques were lower and tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β plasma levels were higher in the groups with diabetes than in controls. There was no correlation between testosterone level and knee torques or proinflammatory cytokines. Concentric and isometric knee flexion and extension torque were negatively correlated with TNF-α, IL-6, and HbA1C. IL-6 and TNF-α were positively correlated with HbA1C. The results of this study demonstrated that muscle strength was not associated with testosterone levels in men with DM2. Low muscle strength was associated with inflammatory markers and poor glycemic control.
Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto , Persona de Mediana Edad , Anciano , Adulto Joven , Testosterona/sangre , Citocinas/sangre , Diabetes Mellitus Tipo 2/fisiopatología , Diabetes Mellitus Tipo 2/sangre , Fuerza Muscular/fisiología , Interleucina-6/sangre , Factor de Necrosis Tumoral alfa/sangre , Mediadores de Inflamación/sangre , Torque , Contracción Isométrica/fisiología , RodillaRESUMEN
Several factors can affect the magnitude of eccentric exercise (ECC)-induced muscle damage, but little is known regarding the effect of the range of motion (ROM) in ECC-induced muscle damage. The purpose of this study was to investigate whether elbow flexor ECC with 120° of ROM (from 60° of elbow flexion until elbow full extension - 180° [120ROM]) induces a greater magnitude of muscle damage compared with a protocol with 60° of ROM (120-180° of elbow flexion [60ROM]). Twelve healthy young men (age: 22 ± 3.1 years; height: 1.75 ± 0.05 m; body mass: 75.6 ± 13.6 kg) performed the ECC with 120ROM and 60ROM using different arms in a random order separated by 2 weeks and were tested before and 24, 48, 72 and 96 h after ECC for maximal voluntary isometric contraction torque (MVC-ISO), ROM and muscle soreness. The 120ROM protocol showed greater changes and effect sizes (ES) for MVC-ISO (-35%, ES: 1.97), ROM (-11.5°, ES: 1.27) and muscle soreness (19 mm, ES: 1.18) compared with the 60ROM protocol (-23%, ES: 0.93; -12%, ES: 0.56; 17°, ES: 0.63; 8 mm, ES: 1.07, respectively). In conclusion, ECC of the elbow flexors with 120° of ROM promotes a greater magnitude of muscle damage compared with a protocol with 60° of ROM, even when both protocols are performed at long muscle lengths.
RESUMEN
Although tissue cooling is widely used in the treatment of musculoskeletal injuries there is still controversy about its effects on muscular performance. The combination of cooling and exercise justifies the study of this topic. The aim was to compare the effects of ice pack and cold-water immersion on the muscular performance parameters of plantar flexors and muscular activation of the triceps surae. 41 healthy men (mean age: 22.1 years, SD: 2.9) were randomly assigned to cooling with either ice pack (n=20) or cold-water immersion (n=21). Independent variables were cold modality (ice pack or cold-water immersion) and pre- and post-cooling measurement time. Dependent variables were muscular performance (measured during isometric and concentric contractions of plantar flexors) and electromyography parameters of the triceps surae (median frequency and root mean square amplitude). Dependent-samples t-tests were used to compare pre- and post-cooling data and independent-samples t-tests were used to compare the difference (pre- and post-cooling) between groups. Ice pack increased isometric peak torque (mean: 9.00 Nm, P=0.01) and both cold modalities reduced muscular activation in triceps surae (P<0.0001); Cold-water immersion and ice pack reduced peak torque and total work during dynamic isokinetic contraction at both velocities (mean: -11,00 Nm, P<0.05) and affected muscular activation in different ways. In conclusion, ice pack increases isometric torque, while both ice pack and cold-water immersion decrease concentric muscular performance. These results indicate that these cooling methods should be chosen with caution, considering the type of task required during training or rehabilitation. New studies investigating other muscle groups and joints are necessary.
Asunto(s)
Crioterapia/métodos , Ejercicio Físico/fisiología , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Adolescente , Adulto , Traumatismos en Atletas/terapia , Electromiografía , Pie , Voluntarios Sanos , Humanos , Hielo , Inmersión , Pierna , Masculino , Músculo Esquelético/lesiones , Variaciones Dependientes del Observador , Termodinámica , Agua , Adulto JovenRESUMEN
We evaluated the effects of chronic allergic airway inflammation and of treadmill training (12 weeks) of low and moderate intensity on muscle fiber cross-sectional area and mRNA levels of atrogin-1 and MuRF1 in the mouse tibialis anterior muscle. Six 4-month-old male BALB/c mice (28.5 ± 0.8 g) per group were examined: 1) control, non-sensitized and non-trained (C); 2) ovalbumin sensitized (OA, 20 µg per mouse); 3) non-sensitized and trained at 50 percent maximum speed _ low intensity (PT50 percent); 4) non-sensitized and trained at 75 percent maximum speed _ moderate intensity (PT75 percent); 5) OA-sensitized and trained at 50 percent (OA+PT50 percent), 6) OA-sensitized and trained at 75 percent (OA+PT75 percent). There was no difference in muscle fiber cross-sectional area among groups and no difference in atrogin-1 and MuRF1 expression between C and OA groups. All exercised groups showed significantly decreased expression of atrogin-1 compared to C (1.01 ± 0.2-fold): PT50 percent = 0.71 ± 0.12-fold; OA+PT50 percent = 0.74 ± 0.03-fold; PT75 percent = 0.71 ± 0.09-fold; OA+PT75 percent = 0.74 ± 0.09-fold. Similarly significant results were obtained regarding MuRF1 gene expression compared to C (1.01 ± 0.23-fold): PT50 percent = 0.53 ± 0.20-fold; OA+PT50 percent = 0.55 ± 0.11-fold; PT75 percent = 0.35 ± 0.15-fold; OA+PT75 percent = 0.37 ± 0.08-fold. A short period of OA did not induce skeletal muscle atrophy in the mouse tibialis anterior muscle and aerobic training at low and moderate intensity negatively regulates the atrophy pathway in skeletal muscle of healthy mice or mice with allergic lung inflammation.
Asunto(s)
Animales , Masculino , Ratones , Asma/patología , Proteínas Musculares/análisis , Músculo Esquelético/química , Atrofia Muscular/patología , ARN Mensajero/análisis , Proteínas Ligasas SKP Cullina F-box/análisis , Ubiquitina-Proteína Ligasas/análisis , Asma/fisiopatología , Enfermedad Crónica , Modelos Animales de Enfermedad , Expresión Génica , Ratones Endogámicos BALB C , Fibras Musculares Esqueléticas/química , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/patología , Atrofia Muscular/genética , Atrofia Muscular/fisiopatología , Condicionamiento Físico Animal , Neumonía/metabolismo , Neumonía/patología , TibiaRESUMEN
Considering that short bouts of stretching, as recommended in rehabilitation and sports activities, induce skeletal muscle and connective tissue adaptation, the hypothesis of this study was that MMP-2 activity is regulated by muscle stretch. The level of MMP-2 activity was, thereby, assessed after stretching in rat soleus muscle. Animals received a single session of stretching (10 stretches lasting 1 min each with 30 s of rest in between) and were evaluated immediately and after 8, 24, 48, 72 and 168 h. To evaluate the effect of repetitive sessions of stretching, three groups of animals were evaluated - one group after 2 sessions, another after 3, and a third after 7. MMP-2 activity was evaluated by zymography and MMP-2 mRNA was assessed by real-time polymerase chain reaction. None of the groups presented MMP-9 activity. MMP-2 activity and mRNA expression did not change after either single or repetitive sessions of stretching. In conclusion, the results of this study indicate that MMP-2 is not involved in the muscle stretch-induced remodeling.
Asunto(s)
Metaloproteinasa 2 de la Matriz/metabolismo , Ejercicios de Estiramiento Muscular/métodos , Músculo Esquelético/metabolismo , Animales , Regulación Enzimológica de la Expresión Génica/fisiología , Masculino , Metaloproteinasa 2 de la Matriz/genética , Metaloproteinasa 9 de la Matriz/metabolismo , Músculo Esquelético/enzimología , Reacción en Cadena de la Polimerasa , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Factores de TiempoRESUMEN
We evaluated the effects of chronic allergic airway inflammation and of treadmill training (12 weeks) of low and moderate intensity on muscle fiber cross-sectional area and mRNA levels of atrogin-1 and MuRF1 in the mouse tibialis anterior muscle. Six 4-month-old male BALB/c mice (28.5 +/- 0.8 g) per group were examined: 1) control, non-sensitized and non-trained (C); 2) ovalbumin sensitized (OA, 20 microg per mouse); 3) non-sensitized and trained at 50% maximum speed _ low intensity (PT50%); 4) non-sensitized and trained at 75% maximum speed _ moderate intensity (PT75%); 5) OA-sensitized and trained at 50% (OA+PT50%), 6) OA-sensitized and trained at 75% (OA+PT75%). There was no difference in muscle fiber cross-sectional area among groups and no difference in atrogin-1 and MuRF1 expression between C and OA groups. All exercised groups showed significantly decreased expression of atrogin-1 compared to C (1.01 +/- 0.2-fold): PT50% = 0.71 +/- 0.12-fold; OA+PT50% = 0.74 +/- 0.03-fold; PT75% = 0.71 +/- 0.09-fold; OA+PT75% = 0.74 +/- 0.09-fold. Similarly significant results were obtained regarding MuRF1 gene expression compared to C (1.01 +/- 0.23-fold): PT50% = 0.53 +/- 0.20-fold; OA+PT50% = 0.55 +/- 0.11-fold; PT75% = 0.35 +/- 0.15-fold; OA+PT75% = 0.37 +/- 0.08-fold. A short period of OA did not induce skeletal muscle atrophy in the mouse tibialis anterior muscle and aerobic training at low and moderate intensity negatively regulates the atrophy pathway in skeletal muscle of healthy mice or mice with allergic lung inflammation.
Asunto(s)
Asma/patología , Proteínas Musculares/análisis , Músculo Esquelético/química , Atrofia Muscular/patología , ARN Mensajero/análisis , Proteínas Ligasas SKP Cullina F-box/análisis , Ubiquitina-Proteína Ligasas/análisis , Animales , Asma/fisiopatología , Enfermedad Crónica , Modelos Animales de Enfermedad , Expresión Génica , Masculino , Ratones , Ratones Endogámicos BALB C , Fibras Musculares Esqueléticas/química , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/patología , Atrofia Muscular/genética , Atrofia Muscular/fisiopatología , Condicionamiento Físico Animal , Neumonía/metabolismo , Neumonía/patología , Tibia , Proteínas de Motivos TripartitosRESUMEN
Matrix metalloproteinases (MMPs) are crucial to the development and maintenance of healthy tissue and are mainly involved in extracellular matrix (ECM) remodeling of skeletal muscle. This study evaluated the effects of chronic allergic airway inflammation (CAAI), induced by ovalbumin, and aerobic training in the MMPs activity in mouse diaphragm muscle. Thirty mice were divided into 6 groups: 1) control; 2) ovalbumin; 3) treadmill trained at 50% of maximum speed; 4) ovalbumin and trained at 50%; 5) trained at 75%; 6) ovalbumin and trained at 75%. CAAI did not alter MMPs activities in diaphragm muscle. Nevertheless, both treadmill aerobic trainings, associated with CAAI increased the MMP-2 and -1 activities. Furthermore, MMP-9 was not detected in any group. Together, these findings suggest an ECM remodeling in diaphragm muscle of asthmatic mice submitted to physical training. This result may be useful for a better understanding of functional significance of changes in the MMPs activity in response to physical training in asthma.
Asunto(s)
Asma/rehabilitación , Diafragma/metabolismo , Condicionamiento Físico Animal , Animales , Asma/enzimología , Asma/fisiopatología , Diafragma/enzimología , Modelos Animales de Enfermedad , Matriz Extracelular/metabolismo , Masculino , Metaloproteinasa 1 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Endogámicos BALB C , Músculo Esquelético/enzimología , Músculo Esquelético/metabolismo , OvalbúminaRESUMEN
OBJECTIVE: To assess the effects of neuromuscular electrical stimulation (NMES) associated with an isokinetic training program in healthy young men and women. METHODS: Twenty participants (ten men, ten women; 21±1.5 years) underwent an isokinetic training program for knee extensors of both sides (three sets of ten concentric repetitions at 30°/s) twice a week for four weeks. One limb underwent only the isokinetic strength training (Ex) while the other underwent the same training but with NMES associated with each contraction (Ex+NMES). The current used for NMES was the Russian current (frequency of 2,500Hz, 50 bursts/s and pulse duration of 200µs). Isometric and isokinetic concentric extensor torque at 30°/s were evaluated. RESULTS: The groups increased their peak torque in both test procedures, with no difference between Ex and Ex+NMES. The angle of peak torque increased for the Ex limb, thus showing a change in the tension-length relationship of the muscle group tested, which did not occur for the Ex+NMES limb. There was also a decrease in acceleration time in both limbs, without any effects from NMES on this variable. CONCLUSIONS: These results showed that the association between NMES and isokinetic concentric voluntary strength training did not improve the strength gains and neuromuscular properties of voluntary strength training itself for healthy young participants of both genders.
OBJETIVO: Verificar os efeitos da estimulação elétrica neuromuscular (EENM) associada a um programa de treinamento isocinético em homens e mulheres jovens e sadios. MÉTODOS: Vinte indivíduos (dez homens, dez mulheres, 21±1,5 anos) submeteram-se a um programa de treinamento isocinético de ambos os seus extensores de joelho (três séries de dez repetições concêntricas a 30°/s) duas vezes por semana por quatro semanas. Um membro foi submetido apenas ao treinamento de força isocinético (Ex) enquanto o outro foi submetido ao mesmo treinamento, mas com EENM associada a cada contração (Ex+EENM). A corrente utilizada para a EENM foi a corrente russa (frequência de 2.500Hz, 50 bursts/s, duração de pulso de 200µs). O protocolo de avaliação incluiu o torque extensor isométrico e isocinético concêntrico a 30°/s. RESULTADOS: Os grupos aumentaram seu pico de torque em ambas as modalidades testadas, sem diferença entre Ex e Ex+EENM. O ângulo do pico de torque aumentou para o membro Ex, mostrando uma alteração da relação comprimento-tensão do grupo muscular testado, o que não aconteceu com o membro Ex+EENM. Houve também uma diminuição no tempo de aceleração de ambos os membros, sem efeito da EENM sobre este parâmetro. CONCLUSÕES: Estes resultados mostraram que a associação entre a EENM e o treinamento voluntário isocinético concêntrico não melhorou os ganhos de força e de propriedades neuromusculares do próprio treinamento de força voluntário para sujeitos jovens e sadios de ambos os gêneros.
RESUMEN
The objective of the present study was to assess the effect of transcutaneous electrical diaphragmatic stimulation (TEDS) on different types of diaphragm muscle fibers. Male Wistar rats (8-12 weeks old) were divided into 2 experimental groups (N = 8 in each group): 1) control, 2) animals submitted to TEDS [frequency = 50 Hz; T(ON)/T(OFF) (contraction/relaxation time) = 2/2 s; pulse duration = 0.4 ms, intensity = 5 mA with a 1 mA increase every 3 min for 20 min] for 7 days. After completing this treatment period, the I, IIA, IIB, and IID diaphragm muscle fibers were identified using the mATPase technique. Statistical analysis consisted of the normality, homoscedasticity and t-tests (P < 0.05). There was a 19.6% (P < 0.05) reduction in the number of type I fibers and a 49.7% increase (P < 0.05) in type IID fibers in the TEDS group compared with the control group. An important result of the present study was that electrical stimulation with surface electrodes was efficient in altering the distribution of fibers in diaphragm muscle. This therapeutic resource could be used in the treatment of respiratory muscle alterations.
Asunto(s)
Diafragma/anatomía & histología , Fibras Musculares Esqueléticas , Estimulación Eléctrica Transcutánea del Nervio , Animales , Masculino , Fibras Musculares Esqueléticas/clasificación , Fibras Musculares Esqueléticas/metabolismo , Ratas , Ratas WistarRESUMEN
The objective of the present study was to assess the effect of transcutaneous electrical diaphragmatic stimulation (TEDS) on different types of diaphragm muscle fibers. Male Wistar rats (8-12 weeks old) were divided into 2 experimental groups (N = 8 in each group): 1) control, 2) animals submitted to TEDS [frequency = 50 Hz; T ON/T OFF (contraction/relaxation time) = 2/2 s; pulse duration = 0.4 ms, intensity = 5 mA with a 1 mA increase every 3 min for 20 min] for 7 days. After completing this treatment period, the I, IIA, IIB, and IID diaphragm muscle fibers were identified using the mATPase technique. Statistical analysis consisted of the normality, homoscedasticity and t-tests (P < 0.05). There was a 19.6 percent (P < 0.05) reduction in the number of type I fibers and a 49.7 percent increase (P < 0.05) in type IID fibers in the TEDS group compared with the control group. An important result of the present study was that electrical stimulation with surface electrodes was efficient in altering the distribution of fibers in diaphragm muscle. This therapeutic resource could be used in the treatment of respiratory muscle alterations.
Asunto(s)
Animales , Masculino , Ratas , Diafragma/anatomía & histología , Fibras Musculares Esqueléticas , Estimulación Eléctrica Transcutánea del Nervio , Fibras Musculares Esqueléticas/clasificación , Fibras Musculares Esqueléticas/metabolismo , Ratas WistarRESUMEN
OBJECTIVE: To evaluate the effects of eccentric isokinetic training on knee range of motion (ROM) of healthy subjects. METHODS: The knee extensor and flexor isokinetic peak torques and ROM of flexion/extension and varus/valgus knee movements during gait of 18 healthy men (21.7±2.2 years; 1.73±0.10m; 68.7±9.4kg; body mass index: 22.6±2kg/m²) were analyzed, before and after six weeks of bilateral eccentric isokinetic training of the knee extensors at 30º/s. RESULTS: The knee extensor torque increased in both limbs (right, from 229±54 to 304±53Nm; p<0.01; and left, from 228±59 to 311±63Nm; p<0.01), without any difference in torque gain between them. The knee flexor peak torque increased (from 114±30 to 123±22Nm; p<0.05), but the hamstrings/quadriceps (H/Q) ratio decreased (from 0.5±0.08 to 0.39±0.07; p<0.01) after the training. There were no differences in the flexion/extension and varus/valgus movements after the training, except for a small change (4°) in valgus for the left knee. CONCLUSIONS: The eccentric isokinetic training of the knee extensors increased the extensor torque and decreased the H/Q ratio, although the effect on the gait pattern seemed negligible in healthy subjects. Associated training for flexors, complementary to the extensor training, seems to be necessary for balance between knee agonists and antagonists.
OBJETIVO: Avaliar os efeitos do treino isocinético excêntrico sobre a amplitude de movimento (ADM) do joelho em sujeitos saudáveis. MÉTODOS: Foram analisados os picos de torque isocinético dos extensores e flexores do joelho e a ADM de flexo/extensão e valgo/varo, durante a marcha, de 18 homens saudáveis (21,7±2,2 anos; 1,73±0,10m; 68,7±9,4kg; índice de massa corpórea: 22,6±2kg/m²) antes e após seis semanas de treino isocinético excêntrico bilateral dos extensores do joelho a 30º/s. RESULTADOS: O torque extensor do joelho aumentou em ambos os membros, direito (de 229±54 para 304±53Nm; p<0,01) e esquerdo (de 228±59 para 311±63Nm; p<0,01) sem diferença de ganho de torque entre eles. O pico de torque flexor aumentou (de 114±30 para 123±22Nm; p<0,05), mas a razão isquiotibiais/quadríceps (I/Q) diminuiu (de 0,5±0,08 para 0,39±0,07; p<0,01) após o treino. Não houve diferença para os movimentos de flexo/extensão e valgo/varo após o treino, exceto uma pequena mudança (4°) no valgo para o joelho esquerdo. CONCLUSÕES: O treino isocinético excêntrico dos extensores do joelho aumentou o torque extensor e diminuiu a razão I/Q, entretanto o efeito sobre o padrão da marcha parece desprezível em sujeitos saudáveis. Um treino associado dos flexores, complementar ao treino dos extensores parece ser necessário para o equilíbrio entre agonistas e antagonistas do joelho.
RESUMEN
OBJETIVO: Avaliar a amplitude de movimento (ADM) e o torque flexor e extensor do joelho após a realização de um programa de alongamento ativo excêntrico dos músculos flexores do joelho. MATERIAIS E MÉTODOS: Trinta e quatro voluntários (23 mulheres e 11 homens), 34,42±9,3 anos, realizaram um programa de alongamento ativo excêntrico dos músculos flexores do joelho na postura em pé, que consistiu de sete repetições de um minuto com 30 segundos de descanso entre as repetições. O programa de alongamento foi realizado duas vezes por semana, durante quatro semanas. A ADM de extensão e o torque flexor e extensor do joelho foram avaliados no dinamômetro isocinético pré e pós-programa de alongamento. O torque foi avaliado nos modos isométrico e isocinético concêntrico e excêntrico a 30º/s e 60º/s. RESULTADOS: Houve aumento na ADM de 53,7±13º para 30,1±16º (p=0,0001), no torque isométrico flexor de 89±32Nm para 93±33Nm (p=0,01) e extensor de 178±67Nm para 187±73Nm (p=0,006). O torque flexor concêntrico e excêntrico a 30º/s aumentou de 90±31Nm para 96±31Nm (p=0,001) e de 100±34Nm para 105±35Nm (p=0,01), respectivamente. O torque extensor concêntrico a 60º/s aumentou de 144±51Nm para 151±58Nm (p=0,02) e o excêntrico a 30º/s de 175±71Nm para 189±73Nm (p=0,01). CONCLUSÕES: O programa de alongamento proposto foi efetivo para aumentar a flexibilidade dos músculos alongados e torque dos grupos musculares agonistas (alongados) e seus antagonistas.
OBJECTIVE: To evaluate the changes in knee range of motion (ROM) and torque of knee flexor and extensor muscles after an active eccentric stretching program for the knee flexor muscles. METHODS: Thirty-four volunteers (23 women and 11 men), aged 34.42±9.3 years, performed an active eccentric stretching program for the knee flexor muscles in the standing posture, consisting of seven repetitions of one minute each, with 30 seconds of resting between them. The stretching program was performed twice a week, for four weeks. Knee extension ROM and the torque of the knee flexor and extensor muscles were evaluated using an isokinetic dynamometer before and after the stretching program. The torque was evaluated in the isometric, isokinetic concentric and eccentric modes at 30º/s and 60º/s. RESULTS: There was an increase in ROM from 53.7±13º to 30.1±16º (p=0.0001), in isometric torque of the flexors from 89±32Nm to 93±33Nm (p=0.01) and of the extensors from 178±67Nm to 187±73Nm (p=0.006). The concentric and eccentric torque of the flexors at 30º/s increased from 90±31Nm to 96±31Nm (p=0.001) and from 100±34Nm to 105±35Nm (p=0.01), respectively. The concentric torque of the extensors at 60º/s increased from 144±51Nm to 151±58Nm (p=0.02), and the eccentric torque at 30º/s increased from 175±71Nm to 189±73Nm (p=0.01). CONCLUSIONS: The stretching program proposed was effective for increasing the flexibility of the stretched muscles and the torque of the agonist (stretched) muscle groups and their antagonists.
Asunto(s)
Humanos , Masculino , Femenino , Alargamiento Óseo , Rodilla , Modalidades de Fisioterapia , Docilidad , TorqueRESUMEN
INTRODUÇÃO: Embora a crioterapia associada à compressão seja recomendada como tratamento imediato após lesão muscular, o efeito de sessões intermitentes desses procedimentos na área de lesão muscular secundária não é bem estabelecido. O objetivo deste estudo foi avaliar o efeito da aplicação intermitente de crioterapia e compressão (três sessões de 30 min a cada 1h30min) na área de lesão do músculo tibialis anterior direito (TAD) do rato. METODOLOGIA: A lesão muscular foi induzida por criolesão no TAD. Vinte e quatro ratos Wistar (340 ± 20g) foram divididos em quatro grupos experimentais: a) O grupo Lesão + Crioterapia (L+C) recebeu tratamentos intermitentes de crioterapia e compressão; b) O grupo Lesão + Placebo (L+P) recebeu tratamento placebo; c) O grupo Lesão (L) não foi submetido a nenhum protocolo de tratamento; e d) o grupo Crioterapia (C) que permaneceu intacto e foi submetido a tratamentos de crioterapia e compressão. Os animais foram sacrificados 24h pós-lesão, sendo os músculos seccionados em criostato e os cortes histológicos corados com Azul de Toluidina para posterior mensuração da área muscular lesada (morfometria). A análise estatística constou da ANOVA e do teste Tukey (p < 0,05). RESULTADOS: A morfometria aplicada 24 horas pós-lesão indicou redução significante da área de lesão muscular no grupo L+C (35,87 ± 4,9 por cento) quando comparado aos grupos L+P (46,4 ± 3,9 por cento; p= 0,001) e L (46,5 ± 4,1 por cento; p= 0,002). CONCLUSÃO: Três sessões de crioterapia e compressão foram eficientes na prevenção do aumento da área de lesão, enquanto somente a compressão não apresentou a mesma efetividade.
INTRODUCTION: Although cryotherapy associated with compression has been recommended as an immediate treatment for muscle injuries, the effect of intermittent sessions of these procedures in the area of secondary muscle injuries has not been clearly established. OBJECTIVE: To evaluate the effect of intermittently applying cryotherapy and compression (three 30-minute sessions at 90-minute intervals) on an injured area of the right tibialis anterior (RTA) muscle in rats. Method: An injury was induced in the RTA muscle by means of cryoinjury. Twenty-four Wistar rats (340 ± 20g) were divided into four experimental groups: a) Injury + Cryotherapy (I+C), which received intermittent cryotherapy and compression; b) Injury + Placebo (I+P), which received placebo treatment; c) Injury (I), which did not undergo any treatment protocols; and d) Cryotherapy, which remained intact and underwent cryotherapy and compression treatment. The animals were sacrificed 24 hours after the injury, and the muscles were sectioned in a cryostat. The histological sections were stained with toluidine blue for subsequent measurement of the area of the muscle injury (morphometry). The statistical analysis consisted of the ANOVA and Tukey tests (p < 0.05). RESULTS: The morphometric analysis 24 hours after the injury indicated that there had been a significant reduction in the area of the muscle injury in the I+C group (35.87 ± 4.9 percent), in comparison with the I+P group (46.4 ± 3.9 percent; p= 0.001) and the I group (46.5 ± 4.1 percent; p= 0.002). CONCLUSION: Three sessions of cryotherapy and compression were efficient in preventing an increase in the injured area, while compression alone did not achieve such effectiveness.
Asunto(s)
Ratas , Crioterapia , Músculo Esquelético/lesiones , Ratas WistarRESUMEN
OBJECTIVE: This study assessed physical function and pain in male and female workers with shoulder impingement syndrome using the Brazilian Portuguese versions of the Disabilities of the Arm, Shoulder and Hand (DASH) and McGill pain questionnaires. METHODS: Twenty-seven assembly line workers (18 men and 9 women; mean age of 33.26 ± 6.49 years) in the school supply industry were evaluated. The duration of the shoulder impingement pain was 31.74 ± 32.92 months and the amount of time of the workers in this industry was 11.08 ± 6.41 years. The DASH questionnaire was used to evaluate functional status and symptoms of the upper limbs of the workers. Using the McGill Pain Questionnaire, the pain was quantified by the number of words chosen and by the pain rating index (PRI). RESULTS: The women presented higher scores (P< 0.05) than the men for both DASH overall and DASH work scores. The women chose more words (17.00 ± 2.59) than the men (13.33 ± 3.16) and also presented the highest total PRI (P< 0.05). CONCLUSIONS: The results obtained in this group of Brazilian workers with shoulder impingement identify the most commonly used descriptors of shoulder pain. Further, this study shows that females are more likely than males to refer physical disability and pain. Also, the DASH and McGill pain questionnaires are important and helpful tools in the clinical evaluation of shoulder impingement syndrome.
OBJETIVO: Este estudo avaliou função física e dor em trabalhadores com síndrome do impacto através das versões brasileiras dos questionários "Disabilities of the Arm, Shoulder and Hand" (DASH) e McGill de dor. MÉTODO: Vinte e sete trabalhadores (18 homens e 9 mulheres; idade média de 33,26 ± 6,49 anos) de uma linha de produção de uma indústria de material escolar foram avaliados. O tempo de duração de dor no ombro era de 31,74 ± 32,92 meses e o tempo de trabalho na indústria era de 11,08 ± 6,41 anos. O questionário DASH foi utilizado para avaliar o estado funcional e os sintomas dos membros superiores dos trabalhadores. Através do questionário McGill de dor, a dor foi quantificada pelo número de palavras escolhidas e pelo índice de classificação da dor (ICD). RESULTADOS: As mulheres apresentaram maiores escores (P< 0,05) que os homens para ambos os módulos do DASH. As mulheres escolheram mais palavras (17,00 ± 2,59) que os homens (13,33 ± 3,16) e também apresentaram o maior ICD total (P< 0,05). CONCLUSÃO: Os resultados obtidos neste grupo de trabalhadores brasileiros com síndrome do impacto do ombro identificam os mais comuns descritores utilizados para dor no ombro. Além disso, este estudo mostra que as mulheres estão mais propensas a relatarem incapacidade física e dor quando comparadas aos homens. Os questionários DASH e McGill de dor são ferramentas importantes e úteis na avaliação clínica da síndrome do impacto do ombro.
Asunto(s)
Humanos , Masculino , Femenino , Dimensión del Dolor , Manguito de los Rotadores , Dolor de HombroRESUMEN
Cyclosporin-A (CsA) is an immunosuppressive drug that acts as an inhibitor of calcineurin, a calcium phosphatase that has been suggested to play a role in skeletal muscle hypertrophy. The aim of the present study was to determine the effect of CsA administration (25 mg kg(-1) day(-1)) on skeletal muscle mass and phenotype during disuse and recovery. Male Wistar rats received vehicle (N = 8) or CsA (N = 8) during hind limb immobilization (N = 8) and recovery (N = 8). Muscle weight (dry/wet) and cross-sectional area were evaluated to verify the effect of CsA treatment on muscle mass. Muscle phenotype was assessed by histochemistry of myosin ATPase. CsA administration during immobilization and recovery did not change muscle/body weight ratio in the soleus (SOL) or plantaris (PL). Regarding muscle phenotype, we observed a consistent slow-to-fast shift in all experimental groups (immobilized only, receiving CsA only, and immobilized receiving CsA) as compared to control in both SOL and PL (P < 0.05). During recovery, no difference was observed in SOL or PL fiber type composition between the experimental recovered group and recovered group receiving CsA compared to their respective controls. Considering the muscle/body weight ratio, CsA administration does not maximize muscle mass loss induced by immobilization. Our results also indicate that CsA fails to block skeletal muscle regrowth after disuse. The present data suggest that calcineurin inhibition by CsA modulates muscle phenotype rather than muscle mass.
Asunto(s)
Inhibidores de la Calcineurina , Ciclosporina/farmacología , Inhibidores Enzimáticos/farmacología , Músculo Esquelético/efectos de los fármacos , Animales , Suspensión Trasera , Masculino , Fibras Musculares Esqueléticas/efectos de los fármacos , Músculo Esquelético/patología , Atrofia Muscular/genética , Atrofia Muscular/patología , Fenotipo , Reacción en Cadena de la Polimerasa , Ratas , Ratas WistarRESUMEN
Cyclosporin-A (CsA) is an immunosuppressive drug that acts as an inhibitor of calcineurin, a calcium phosphatase that has been suggested to play a role in skeletal muscle hypertrophy. The aim of the present study was to determine the effect of CsA administration (25 mg kg-1 day-1) on skeletal muscle mass and phenotype during disuse and recovery. Male Wistar rats received vehicle (N = 8) or CsA (N = 8) during hind limb immobilization (N = 8) and recovery (N = 8). Muscle weight (dry/wet) and cross-sectional area were evaluated to verify the effect of CsA treatment on muscle mass. Muscle phenotype was assessed by histochemistry of myosin ATPase. CsA administration during immobilization and recovery did not change muscle/body weight ratio in the soleus (SOL) or plantaris (PL). Regarding muscle phenotype, we observed a consistent slow-to-fast shift in all experimental groups (immobilized only, receiving CsA only, and immobilized receiving CsA) as compared to control in both SOL and PL (P < 0.05). During recovery, no difference was observed in SOL or PL fiber type composition between the experimental recovered group and recovered group receiving CsA compared to their respective controls. Considering the muscle/body weight ratio, CsA administration does not maximize muscle mass loss induced by immobilization. Our results also indicate that CsA fails to block skeletal muscle regrowth after disuse. The present data suggest that calcineurin inhibition by CsA modulates muscle phenotype rather than muscle mass.