Curso Temporal de los Efectos Agudos de una Sesión de Estiramiento Muscular en Sujetos Jóvenes y Sanos / Time Course of the Acute Effects of a Muscle Stretching Session in Young and Healthy Subjects

Introducción. La duración de los efectos agudos del estiramiento muscular y su relación con el volumen total de estiramiento es un tema controversial. Método. Se distribuyeron aleatoriamente 29 varones jóvenes y deportistas en tres grupos: Control, "protocolo corto" (5 estiramientos x 30' segundos) y "protocolo largo" (10 estiramientos x 30 segundos). Para medir el efecto se usó el Active Knee Extension Test en forma previa y posterior a los 0, 3, 7, 12, 18 y 25 minutos. Cada medición se grabó en video, y se identificó el rango máximo de estiramiento con el software Kinovea. Se realizó comparación pre y postintervención entre grupos e inter grupo. Se incorporó análisis post hoc en medidas repetidas. Resultados. No hubo diferencias en la medición preintervención entre los grupos (P=0,266). Ambos protocolos tuvieron cambios significativos (P<0,007) respecto del grupo control (P=0,65). Todas las mediciones postintervención comparadas con la preintervención presentan diferencias en el protocolo corto (P≤0,018) y largo (P≤0,009). Hubo diferencia entre el grupo control con el de protocolo corto (P≤0,014) y control con protocolo largo (P≤0,004) para todas las mediciones, y una diferencia entre ambos protocolos en el post inmediato (P=0,033) pero no para las mediciones posteriores (P≤0,139). Conclusión. Un protocolo de 150 segundos de estiramiento estático en isquiotibiales en varones asintomáticos jóvenes, presenta efectos por al menos 25 minutos. Al duplicar a 300 segundos sólo presenta diferencia en la medición inmediatamente posterior. Por lo tanto, ambos protocolos son igualmente efectivos, pero el protocolo corto es más eficiente.

Background. The duration of the acute effects of muscle stretching and its relationship with the total volume of stretching is a controversial issue. Methods. 29 young male athletes were randomly distributed into three groups: control, "short protocol" (5 stretches x 30'') and "long protocol" (10 stretches x 30''). To measure the effect, the Active Knee Extension Test was used before and after 0, 3', 7', 12', 18' and 25'. Each measurement was videotaped, and the maximum range of stretch was identified using the Kinovea software. A pre-post intervention comparison was made between groups and inter groups. Post hoc analysis was incorporated into repeated measures. Results. There were no differences in the pre-intervention measurement between the groups (P=0.266). Both protocols had significant changes (P<0.007) compared to the control group (P=0.65). All post-intervention measurements compared to pre-intervention present differences in the short (P≤0.018) and long (P≤0.009) protocol. There was a difference between the control group with the short protocol (P≤0.014) and the control group with the long protocol (P≤0.004) for all measurements, and a difference between both protocols in the immediate post (P=0.033) but not for the measurements. subsequent measurements (P≤0.139). Conclusion. A protocol of 150'' of static stretching in hamstrings in asymptomatic young men, presents effects for at least 25'. When doubling at 300'', it only presents a difference in the immediately subsequent measurement. Therefore, both protocols are equally effective, but the short protocol is more efficient.

A 120-second stretch improves postural control and plantar pressure: quasi-experimental study

ABSTRACT BACKGROUND: There are no studies on long-term bilateral calf stretching in relation to balance and plantar pressure. OBJECTIVES: To demonstrate that there is better control of posture and pressures after continuous stretching of the posterior calf muscles. DESIGN AND SETTING: Pre and post-intervention study conducted in a private clinic. METHODS: We measured static footprints and stabilometry before and after continuous passive plantar flexor stretching of duration 120 seconds, among 24 healthy subjects. RESULTS: We found differences in Y displacement with eyes closed (P = 0.010), but not among other variables with eyes closed: X displacement (P = 0.263); surface (P = 0.940); laterolateral speed displacement (P = 0.279); and anteroposterior speed displacement (P = 0.914). There were also no differences in eyes-open variables: X displacement (P = 0.341); Y displacement (P = 0.491); surface (P = 0.167); laterolateral speed displacement (P = 0.852); and anteroposterior speed displacement (P = 0.079). The plantar pressures in the heel (maximum pressure, P = 0.048; mean pressure, P = 0.001) and in the midfoot (maximum pressure, P = 0.004; mean pressure, P = 0.004) were reduced, but not in the forefoot (maximum pressure, P = 0.391; mean pressure, P = 0.225). The surface became larger in the forefoot (P = 0.000) and midfoot (P = 0.021). CONCLUSIONS: Continuous static stretching of plantar flexors for 120 seconds improved stance balance and reduced plantar pressures (maximum and mean) in the rearfoot and midfoot. It also increased the surface in the midfoot and forefoot. TRIAL REGISTRATION: at clinicaltrials.gov, under the number NTC03743168.

Effect of Dry Needling Stimulation of Myofascial Trigger Point on Sample Entropy of Electromyography of Gastrocnemius Injured Site in Rats / 针刺研究

OBJECTIVE: To attempt to establish an objective quantitative indicator to characterize the trigger point activity, so as to evaluate the effect of dry needling on myofascial trigger point activity. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into blank control group, dry needling (needling) group, stretching exercise (stretching) group and needling plus stretching group (n＝6 per group). The chronic myofascial pain (trigger point) model was established by freedom vertical fall of a wooden striking device onto the mid-point of gastrocnemius belly of the left hind-limb to induce contusion, followed by forcing the rat to make a continuous downgrade running exercise at a speed of 16 m/min for 90 min on the next day which was conducted once a week for 8 weeks. Electromyography (EMG) of the regional myofascial injured point was monitored and recorded using an EMG recorder via electrodes. It was considered success of the model if spontaneous electrical activities appeared in the injured site. After a 4 weeks' recovery, rats of the needling group were treated by filiform needle stimulation (lifting-thrusting-rotating) of the central part of the injured gastrocnemius belly (about 10 mm deep) for 6 min, and those of the stretching group treated by holding the rat's limb to make the hip and knee joints to an angle of about 180°, and the ankle-joint about 90° for 1 min every time, 3 times altogether (with an interval of 1 min between every 2 times). The activity of the trigger point was estimated by the sample entropy of the EMG signal sequence in reference to Richman's and Moorman's methods to estimate the curative effect of both needling and exercise. RESULTS: After the modeling cycle, the mean sample entropies of EMG signals was significantly decreased in the model groups (needling group [0.034±0.010], stretching group [0.045±0.023], needling plus stretching group [0.047±0.034]) relevant to the blank control group (0.985±0.196, P0.05), suggesting a better efficacy of dry needling in easing trigger point activity. CONCLUSION: Dry needling is able to relieve myofascial trigger point activity in rats, which is better than that of simple passive stretching therapy.

Efeitos do ultrassom terapêutico associados ao alongamento estático sobre parâmetros histomorfométricos longitudinais de sóleos imobilizados de ratos / Effects of therapeutic ultrasound associated with static stretching on longitudinal histomorphometric parameters of immobilized soleus of rats

O músculo é um tecido dotado de plasticidade que se adapta a diferentes estímulos. A imobilização causa danos ao sistema muscular incluindo atrofia, perda da extensibilidade e resistência muscular. O alongamento muscular e o ultrassom terapêutico são modalidades utilizadas para acelerar o processo de reparo muscular, provendo aumento da síntese proteica e melhora da extensibilidade. OBJETIVO: Comparar o uso do ultrassom terapêutico, associado ao alongamento, na remobilização de músculo sóleo, de ratos, submetido ao encurtamento muscular, sobre os aspectos histomorfométricos longitudinais. MATERIAIS E MÉTODOS: Vinte e oito ratos Wistar foram imobilizados por 15 dias e, após liberados do aparato de imobilização, distribuídos em quatro grupos: grupo (GA) apenas remobilizado por alongamento durante 10 dias; e os demais foram submetidos a 10 dias de intervenção terapêutica do ultrassom de 1MHz a 1,0W/cm² (GAUS 1,0); 0,5W/cm² (GAUS 0,5); e 0,2W/cm² (GAUS 0,2), e posterior alongamento dos músculos sóleos. Ao final do tratamento, os animais foram eutanasiados e tiveram seus músculos removidos para posterior análise histológica dos parâmetros longitudinais (contagem de sarcômeros). RESULTADOS: Na análise intragrupo, quanto ao comprimento muscular, apenas o grupo GAUS 0,5 não teve diferença significativa. Quanto à contagem de sarcômeros, os grupos GA e GAUS 0,2 tiveram diferença significativa. Quanto ao tamanho dos sarcômeros, nenhum grupo teve diferença significativa. Na análise intergrupos, nenhum grupo apresentou diferença significativa. CONCLUSÃO: O alongamento foi insuficiente para reverter os efeitos da imobilização. Quando associado ao ultrassom terapêutico, a dose 0,5W/cm² recuperou o comprimento muscular, e as doses 1,0 e 0,5W/cm² contribuíram para o aumento da quantidade dos sarcômeros em série.

The muscle tissue is endowed with plasticity that adapts to different stimuli. Immobilization causes damage to the musculature including atrophy, loss of muscle strength and extensibility. The stretching and ultrasound treatment modalities are used to speed up muscle repair process as they can increase protein synthesis and improve extensibility. OBJECTIVE: To compare the use of therapeutic thermal and non thermal ultrasound, associated with stretching, in the remobilization of the soleus muscle of rats subjected to position of muscle shortening on aspects histomorphometric longitudinal muscle.} METHODS: 28 rats were immobilized for 15 days, later released from the apparatus and divided into four groups: group AG only remobilized by stretching for 10 days and the others were subjected to 10 days of therapeutic intervention 1MHz of ultrasound at 1.0W/cm² (GAUS 1.0), 0.5W/cm² (GAUS 0.5), and 0.2 W/cm² (GAUS 0.2), and further stretching to the soleus. At the end of treatment, the animals were sacrificed and their soleus muscles were removed for later histological analysis of longitudinal parameters (count of sarcomeres). RESULTS: At intragroup analysis on the muscle length, only the group GAUS 0.5 did not present significant difference. The count of sarcomeres in the groups GA and GAUS 0.2 was statistically different. The size of the sarcomeres in both groups had no statistically significant difference. In inter-group analysis both groups had no statistically significant difference for any of the variables. CONCLUSION: The stretching was insufficient to reverse the effects of immobilization. When associated with therapeutic ultrasound, the dose 0.5 W/cm² recovered muscle length significantly, and the doses 1.0 and 0.5 W/cm² contributed to the significant increase of the number of sarcomeres in immobilized muscles.

Alterações morfofuncionais musculares em resposta ao alongamento passivo em modelo animal de imobilização prolongada de membro posterior / Muscle morphological changes in response to passive stretching in an animal model of prolonged immobilization of hind limb

INTRODUÇÃO: O alongamento passivo ou estático (EAL) é frequentemente utilizado em programas de reabilitação e na área desportiva; porém, as alterações morfofuncionais ocorridas ainda não estão bem claras, principalmente após imobilização prolongada. OBJETIVOS: Examinar as alterações morfofuncionais musculares produzidas em resposta a três semanas de exercícios de EAL em um modelo animal de imobilização prolongada de membro posterior (MP) em posição encurtada. MÉTODOS: Foram utilizados 32 ratos Wistar divididos em quatro grupos (n = 8, em cada): A - grupo controle (CONT), B - grupo imobilizado por 21 dias (IMOB), C - grupo remobilizado por 21 dias (LIVRE), D - grupo alongados por 21 dias (ALONG). Foram comparadas as variações morfofuncionais entre grupos experimentais. As variáveis foram: peso corporal e muscular, comprimento muscular e ósseo, número de miofibrilas e quantidade de colágeno, determinadas através de histomorfometria muscular por contraste de cor. RESULTADOS: A IMOB do bíceps femoral em posição encurtada produziu uma importante hipotrofia com hiperplasia muscular compensatória, além do aumento (p < 0,05) na deposição de colágeno no perimísio e intramuscular de ratos. A remobilização livre ou o alongamento passivo reduziram significativamente (p < 0,05) estas alterações morfofuncionais observados no grupo IMOB. CONCLUSÃO: Através desses resultados, pode-se concluir que tanto o EAL quanto a remobilização livre promovem a restauração das alterações morfofuncionais no bíceps femoral esquerdo induzida pela imobilização prolongada, embora somente o EAL foi capaz de reduzir a relação entre colágeno/músculo.

BACKGROUND: Passive or static stretching (ALMP) is often used in rehabilitation programs and in sports; however, the morphological changes occurred are not very clear, especially after prolonged immobilization. AIMS:This study aimed to examine the muscle morphological and functional changes produced in response to three weeks of ALMP in an animal model of prolonged immobilization of hind limb (HL) in the short range. METHODS: For this purpose, 32 rats (Wistar) were used and divided in 4 groups (n = 8 each): A- control group (CONT), B - immobilized group for 21 days (IMMOB), C - remobilized group for 21 days (FREE), D - elongated group for 21 days (ELONG). The variables evaluated were body weight and muscle mass, muscle and bone length, number of myofibrils and quantity of collagen, determined by histomorphometry muscle by color contrast. The morphological variations between all the experimental groups were compared. RESULTS: The IMMOB of the femoral biceps in shortened position produced important muscular atrophy with compensatory hyperplasia, and increase (p <0.05) in collagen deposition in the perimysium and intramuscular of rats. The free remobilization and the passive stretching reduced significantly (p <0.05) these morphological changes observed in group IMMOB. CONCLUSIONS: Based on these results, it was concluded that both passive stretch and free remobilization promote restoration of the morphological changes induced by prolonged immobilization in the left femoral biceps of rats; however only passive stretching was able to reduce the correlation between collagen/muscle.

Influência do número de séries e tempo de alongamento estático sobre a flexibilidade dos músculos isquiotibiais em mulheres sedentárias / Influence of the number of sets and time of static stretching on the flexibility of hamstring muscles in sedentary women

INTRODUÇÃO E OBJETIVO: Os exercícios de alongamento são frequentemente utilizados em programas de reabilitação e na área desportiva, porém, a duração ideal e o número de séries ainda não foram determinados. O objetivo do estudo foi avaliar os efeitos de 10 séries de 30 segundos e três séries de três minutos de alongamento estático passivo na flexibilidade dos músculos isquiotibiais, comparando diferentes volumes de alongamento dentro de 10 minutos. Além disso, verificar se existe diferença entre os dois programas de alongamento ao término do protocolo e após cinco meses. MÉTODOS: 25 mulheres (17 a 25 anos) foram distribuídas aleatoriamente em três grupos: grupo GC (controle), G30 e G3. O G30 alongou 10 X 30 segundos e o G3 3 X 3 minutos. O alongamento foi realizado por meio de um sistema de polias, utilizando-se 10 por cento do peso corporal da voluntária. Este protocolo durou 6 semanas. As mensurações foram feitas no início do protocolo (Av1), após seis semanas (Av2) e após cinco meses (Av3). Foi mensurada a amplitude de movimento (ADM) de extensão do joelho com 90º de flexão do quadril. A análise de variância (Anova) com dois fatores cruzados de medidas repetidas foi usada com nível de significância de 5 por cento (p < 0,05). RESULTADOS: Não houve diferença estatisticamente significante na ADM de joelho entre 30 segundos (G30) e três minutos (G3) após seis semanas (Av2) (p > 0,05) e após cinco meses (Av3) (p > 0,05). Tanto o G30 quanto o G3 apresentaram aumento da flexibilidade ao término do protocolo (Av1xAv2) (p < 0,05) e após cinco meses (Av1xAv3) (p < 0,05). CONCLUSÕES: Dez séries de 30 segundos e três séries de três minutos podem aumentar a flexibilidade dos isquiotibiais e manter a flexibilidade adquirida após cinco meses do término da intervenção.

INTRODUCTION AND OBJECTIVE: Stretching exercises are largely used in rehabilitation programs, but the ideal duration and the number of sets have not been determined yet. The purpose of this study was to evaluate the effects of 10 sets-30 seconds and 3 sets-3 minutes of static stretch on flexibility of hamstring muscles, comparing different volumes within 10 minutes. Moreover, to verify the difference between the two stretching programs. METHOD: 25 women (17 to 25 years old) were randomly assigned to one of 3 groups: group GC (control), G30 and G3. G30 stretched 10 X 30 seconds and G3 3 X 3 minutes. In all volunteers the stretching was performed by a pulley system, using weight corresponding to 10 percent of their body weight. This protocol took 6 weeks. Measurements were taken at the beginning of the protocol (Av1), after 6 weeks (Av2), and after 5 months (Av3). Flexibility of the hamstring was determined by measuring knee extension range of movement (ROM) with 90º of hip flexion. A two-way repeated measures Analysis of Variance (Anova) was used and significance level was set at 5 percent (p < 0.05). RESULTS: There was no statistically significant difference between 30 seconds (G30) and 3 minutes (G3) in knee extension ROM after 6 weeks (Av2) (p >0.05) and neither after 5 months (Av3) (p>0.05). Both the G30 as the G3 showed increasing flexibility at the end of protocol (Av1xAv2) (p<0.05) and after 5 months (Av1xAv3) (p<0.05). CONCLUSION: Stretching sets of 30 seconds and 3 minutes can increase the hamstrings flexibility and keep the flexibility obtained after 5 months from the end of intervention. There was no difference on the flexibility obtained with sets of 30 seconds or 3 minutes.

The Effect of Passive Stretching on the Spasticity of Ankle Plantar Flexor Muscles

OBJECTIVE: This study was designed to evaluate the effect of stretching on decreasing spasticity of ankle plantar flexor muscles by biomechanical assessments. METHOD: Twenty two ankle joints of nineteen patients with upper motor neuron lesion were included. The spasticity was assessed both clinically and biomechanically before and after stretching of ankle plantar flexor muscles by tilt table. For clinical assessment modified Ashworth scale (MAS) was used. For biomechanical assessment, ankle plantar flexor muscles were stretched isokinetically while EMG signals were recorded simultaneously and peak eccentric torque, stiffness index and stretch reflex threthold speed (SRTS) were measured. RESULTS: Two cases showed improvement in MAS after stretching but the others did not. SRTS of ankle plantar flexor was increased significantly while peak eccentric torque and stiffness index were unchanged. CONCLUSION: Passive stretching of ankle plantar flexor muscles decreased the stretch threshold, that is a neural component of spasticity but it did not decrease the mechanical component of spasticity.