Association between knee-to-hip flexion ratio during single-leg vertical landings, and strength and range of motion in professional soccer players.

The aim of this study was to test the correlation between knee-to-hip flexion ratio during a single leg landing task and hip and knee strength, and ankle range of motion. Twenty-four male participants from a professional soccer team performed a continuous single leg jump-landing test during 10s, while lower limb kinematics data were collected using a motion analysis system. After biomechanical testing, maximal isometric hip (abduction, extension, external rotation), knee extension and flexion strength were measured. Maximum ankle dorsiflexion range of motion was assessed statically using the weight bearing lunge test. Pearson correlation coefficients were calculated to determine the associations between the predictor variables (knee and hip strength, and ankle ROM) and the main outcome measure (knee-to-hip flexion ratio). Correlation between knee-to-hip flexion ratio and hip abductors strength was significant (r = -0.47; p = 0.019). No other significant correlations were observed among the variables (p > 0.05). These results demonstrated that a lower hip abductors strength in male soccer players was correlated with a high knee-to-hip flexion ratio during landing from a single leg jump, potentially increasing knee overload by decreasing energy absorption at the hip. The results provide a novel proposal for the functioning of hip muscles to control knee overload.

Blood flow restriction training promotes hypotensive effect in hypertensive middle-age men / Efecto hipotensor producido por entrenamiento de restricción vascular sanguíneo en hipertensos de mediana edad

Objectives: The purposes of this study were a) to analyze the hemodynamic responses of two methods of resistance training (vascular occlusion vs. traditional) and, b) to demonstrate the effectiveness of vascular occlusion training method on the regulation of blood pressure in hypertensive subjects. Methods: Ten men of middle age (44.9±5.1 years, 83.7±12. kg, 174.1±8.1cm) performed two different protocols of resistance exercises (3 sets until concentric failure; leg press exercise; 60 sec pause between sets): a) with blood flow restriction (30% of 1RM intensity) and b) high intensity exercise (70% of 1RM intensity). Middle thigh muscle circumference was estimated and hemodynamic variables (heart rate, systolic and diastolic blood pressure) were measured before, immediately after and every 10 min (until 60 min) post exercise. The rate of perceived exertion was also utilized after exercise protocol. All subjects were encouraged not to perform the Valsalva maneuver. Results: Both protocols showed a significant reduction of systolic, diastolic and mean arterial blood pressure and heart rate post 10 until 60 min compared to values immediately post exercise (p<0.05). The blood flow restriction group showed a significant reduction (p<0.05) of diastolic blood pressure 20 min post-exertion time compared to rest values. In addition, the magnitude of the effect size about diastolic blood pressure revealed a large magnitude of effect at the 20' and 30 post-effort in the blood flow restriction group. Conclusion: Blood flow restriction protocol promoted a hypotensive effect during 60 min after it is realization

Objetivos: Los objetivos de este estudio fueron: a) analizar las respuestas hemodinámicas de dos métodos de entrenamiento de resistencia (oclusión vascular versus tradicional) y b) demostrar la efectividad del método de entrenamiento de oclusión vascular en la regulación de la presión arterial en sujetos hipertensos. Métodos: Diez hombres de mediana edad (44,9±5,1 años, 83,7±12 kg, 174,1±8,1 cm) realizaron dos protocolos diferentes de ejercicios de fuerza (3 series hasta el fallo concéntrico, ejercicio de ejercicios de pierna, pausa de 60 segundos entre series): a) Con restricción del flujo sanguíneo (30% de intensidad de 1RM) y b) ejercicio de alta intensidad (70% de intensidad de 1RM). Se estimó la circunferencia muscular media del muslo y se midieron las variables hemodinámicas (frecuencia cardíaca, presión arterial sistólica y diastólica) antes, inmediatamente después y cada 10 min (hasta 60 minutos) después del ejercicio. La escala de esfuerzo percibido también se utilizó después del protocolo de ejercicio. Se animó a todos los sujetos a no realizar la maniobra de Valsalva. Resultados: Ambos protocolos mostraron una reducción significativa de la presión arterial sistólica, diastólica y media ya frecuencia cardíaca post 10 hasta 60 min en comparación con los valores inmediatamente después del ejercicio (p<0.05). El grupo de restricción del flujo sanguíneo mostró una reducción significativa (p<0.05) de la presión arterial diastólica 20 minutos después del esfuerzo en comparación con los valores de reposo. Además, la magnitud del tamaño del efecto sobre la presión arterial diastólica reveló una gran magnitud de efecto a los 20 ‘ y 30’ post-esfuerzo en el grupo de restricción de flujo sanguíneo. Conclusión: El protocolo de restricción del flujo sanguíneo promovió un efecto hipotensor durante 60 minutos después de su realización

Análise da força muscular em indivíduos treinados na plataforma de instabilidade / Analysis of the muscular force in subjects trained in the platform of instability

O objetivo do estudo foi comparar a variabilidade do grau de força muscular pelo teste 10 repetições máximas (RM) antes e depois do treinamento de força na execução do exercício agachamento no Smith Machine em indivíduos treinando com e sem a plataforma de instabilidade (PI). A amostra foi composta de 30 homens jovens, com idades entre 20 e 25 anos, peso entre 75 e 80 Kg e altura entre 175 e 180 cm. Os indivíduos foram separados aleatoriamente em 3 grupos: 1) grupo plataforma de instabilidade (GPI); 2) grupo padrão (GP); 3) grupo controle (GC). Todos os indivíduos realizaram o teste de 10RM 48 H antes do 1º dia de treinamento e 48 H depois do último dia de treinamento. Os indivíduos do GPI e do GP realizaram o treinamento de força 3 vezes por semana durante 4 semanas com a carga constante (carga do teste 10RM) e ao final de cada treinamento respondiam a escala de percepção subjetiva de esforço (PSE). A ANOVA de duas entradas, seguida, pelo teste post hoc de Tuckey mostrou diferença significativa entre o teste e o reteste 10RM no GP e no GPI (p<0,0001, ambos os grupos), sem mudanças no GC (P>0,05). As médias do reteste comparadas entre os grupos mostraram redução significativa no GP (P<0,02) e GC (P<0,0001) em relação ao GPI. As médias do GP apresentaram aumento significativo em relação ao GC (P<0,01). Em relação a PSE o teste t-student mostrou valores próximos ao absoluto em ambos os grupos (GPI e GP) após a 4º semana de treinamento, e as médias intergrupos relataram diferença significativa (10,6+ 0,6 – GP; 11,8+ 0,2 – GPI, P<0,0001). A conclusão mostrou que o treinamento com instabilidade gera através da adaptação neural habilidade de maior coordenação inter e intramuscular, conseqüentemente, melhora da atividade dos agonistas, sinergistas, estabilizadores, assim, apresentou aumento da produção de força, quando comparado com ações de estabilidade.

The aim of the study was to compare the variability of the degree of muscular force for the test 10 maximum repetitions (RM) before and after the strength training in the execution of the exercise squat in individuals with and without the platform of instability (PI). The sample was composed of 30 young men, with ages between 20 and 25 years, body weight between 75 and 80 kg and height between 175 and 180 cm. The individuals were separate in 3 groups: 1) group platform of instability (GPI); 2) group pattern (GP); 3) group control (GC). All of the individuals accomplished the test of 10RM 48 H before the 1st day of training and 48 H after the last day of training. The individuals of GPI and of GP they accomplished the strength training per 3 times for 4 weeks with the constant load (load of the test 10RM) and at the end of each training they answered the scale of subjective perception of effort (SPE). The ANOVA two way from post hoc Tuckey results showed significant difference between the test and the retest 10RM in GP and in GPI (p <0.0001, both groups), without changes in GC (P>0.05). The averages of the retest compared among the groups showed significant reduction in GP (P <0.02) and GC (P <0.0001) in relation to GPI. The averages of GP presented significant increase in relation to GC (P <0.01). SPE told himself close values to the absolute in both groups (GPI and GP) after to 4th week of training, and the averages inter-groups told significant difference (10,6+ 0,6 - GP; 11,8+ 0,2 - GPI, P <0.0001). The conclusion shows that the training with instability generates through the adaptation neural, ability of larger coordination inter and intramuscularly, consequently, it gets better of the activity of the agonists, synergists, stabilize. However showed increase of the production of force, when compared with actions of stability.