ABSTRACT
Previous study reported that baseball pitchers had a decreased shoulder internal rotation (IR) range of motion after pitching. However, whether the decreased range of motion associated with pitching is caused by tightness of the posterior shoulder has not been clarified yet. The joint stiffness in the passive torque can be compared with posterior shoulder tightness before and after pitching. Hence, this study aimed to compare shoulder IR stiffness based on passive torque before and after pitching in baseball pitcher. Eleven health male collage baseball pitchers were recruited. Passive torque during IR (max IR, peak torque and stiffness) of dominant and non-dominant arms was measured using an isokinetic dynamometer. Measurements were taken before, after, and post 24 hours after pitching (105 pitches). It was observed that after pitching, max IR and peak torque were significantly decreased compared to those before pitching. However, there was no difference in the stiffness of passive torque among three measurements. In conclusion, healthy college baseball pitchers have a decreased IR range of motion after pitching. However, this result is not due to posterior shoulder tissue tightness, but because of altered stretch tolerance.
ABSTRACT
CONTEXTUALIZAÇÃO: Rigidez passiva adequada do quadril pode impedir movimentos excessivos dos membros inferiores no plano transverso durante a realização de atividades funcionais. O fortalecimento muscular dos rotadores laterais do quadril poderia ser utilizado na tentativa de aumentar a rigidez dessa articulação. No entanto, a relação entre rigidez passiva e força dos músculos do quadril não está documentada na literatura. OBJETIVO: Investigar a associação entre rigidez passiva do quadril durante o movimento de rotação medial e torque concêntrico dos rotadores laterais dessa articulação em indivíduos saudáveis. MÉTODO: Foram avaliados 26 indivíduos com média de idade de 24,42±2,77 anos. Para quantificação da rigidez passiva do quadril, o torque passivo de resistência durante a rotação medial dessa articulação foi mensurado por um dinamômetro isocinético. A rigidez foi determinada como a inclinação média da curva de torque passivo obtida nos primeiros 20° do movimento. Eletromiografia foi utilizada para verificar o repouso dos músculos do quadril durante esse procedimento. O dinamômetro isocinético também foi utilizado para avaliação do pico de torque e trabalho máximo dos rotadores laterais do quadril em uma amplitude de 55° de rotação. RESULTADOS: Regressões lineares demonstraram coeficientes de correlação r=0,70 (R²=0,50/p<0,001) e r=0,77 (R²=0,59/p<0,001) entre rigidez do quadril e as medidas de pico de torque e trabalho muscular dos rotadores laterais, respectivamente. CONCLUSÕES: Existe associação de moderada a boa entre rigidez passiva do quadril e torque concêntrico dos rotadores laterais dessa articulação. A associação demonstrada sugere que o fortalecimento dos rotadores laterais pode ser eficaz em aumentar a rigidez do quadril.
BACKGROUND: Adequate passive stiffness of the hip joint can prevent the occurrence of excessive transverse plane lower limb movement during functional activities. Strength training of the hip lateral rotator muscles can be used to increase the stiffness of this joint. However, the relationship between hip joint passive stiffness and muscle strength remains undocumented in the literature. OBJECTIVE: To investigate the association between hip passive stiffness measured during medial rotation and hip lateral rotator concentric torque in healthy young adults. METHOD: Twenty-six individuals with mean age of 24.42±2.77 years participated in the present study. To quantify hip stiffness, the passive resistance torque during medial rotation was measured using an isokinetic dynamometer. Stiffness was determined by the mean slope of the passive torque curve obtained in the first 20° of motion. Electromyography was used to ensure inactivity of the hip muscles during this procedure. The isokinetic dynamometer was also used for assessment of hip lateral rotator peak torque and work in a range of motion of 55° of rotation. RESULTS: Linear regressions demonstrated correlation coefficients of r=0.70 (R²=0.50/p<0.001) and r=0.77 (R²=0.59/p<0.001) between hip passive stiffness and the measures of lateral rotator peak torque and work, respectively. Conclusions: There is a moderate to good association between hip passive stiffness and lateral rotator concentric torque. This association suggests that lateral rotator strength training can increase hip stiffness.
Subject(s)
Adolescent , Adult , Female , Humans , Male , Young Adult , Hip Joint/physiopathology , Muscle, Skeletal/physiopathology , Range of Motion, Articular , Rotation , TorqueABSTRACT
BACKGROUND: The presence of inadequate levels of passive ankle stiffness have been associated with the occurrence of movement disorders, the development of pathological conditions and the reduction in the performance of functional activities such as walking, running and jumping. Therefore, clinical tests to evaluate ankle stiffness may be useful for the physical therapy assessment. OBJECTIVES: To investigate the concurrent validity and the intra- and inter-examiner reliability of clinical measures developed to assess passive stiffness of the ankle joint during dorsiflexion movement. METHODS: Fifteen healthy participants underwent to test-retest evaluations of their ankles by two examiners. Two clinical measures were performed: 'position of first detectable resistance' and 'change in passive resistance torque'. The results of these tests were compared to the passive stiffness measured with an isokinetic dynamometer, in which the electromyography activity of specific muscles was monitored to ensure that the test was performed passively (gold standard measure). RESULTS: Pearson correlation coefficients ranged from r=-0.81 to -0.88 (p<0.001) for the correlation between the passive ankle stiffness measured with the isokinetic dynamometer and the results of the clinical measure 'position of the first detectable resistance'. For the measure of 'change in passive resistance torque', these coefficients ranged from r=0.72 to 0.83 (p<0.004). The Intraclass Correlation Coefficients (ICCs) for the intra- and inter-examiner reliability ranged from 0.75 to 0.98. CONCLUSION: The clinical measures presented satisfactory validity and reliability to be used in clinical practice.
CONTEXTUALIZAÇÃO: Níveis inadequados de rigidez passiva do tornozelo têm sido associados à ocorrência de disfunções de movimento, ao desenvolvimento de patologias e à redução no desempenho em atividades como marcha, corrida e salto. Testes clínicos para investigar a rigidez dessa articulação podem ser úteis no processo de avaliação fisioterápica. OBJETIVOS: Investigar a validade concorrente e as confiabilidades intra e interexaminadores de medidas clínicas para avaliação da rigidez passiva do tornozelo durante o movimento de dorsiflexão. MÉTODOS: Quinze voluntários saudáveis foram submetidos a avaliações teste-reteste do tornozelo por dois examinadores. Duas medidas clínicas foram realizadas: "posição de primeira resistência detectável" e "mudança do torque passivo de resistência". Os resultados desses testes foram comparados à medida da rigidez passiva realizada com um dinamômetro isocinético, no qual a atividade eletromiográfica dos músculos foi monitorada para garantir que o teste fosse realizado passivamente (medida padrão-ouro). RESULTADOS:Os Coeficientes de Pearson variaram de r=-0,81 a -0,88 (p<0,001) para a correlação entre a medida da rigidez com o dinamômetro isocinético e os resultados da medida "posição de primeira resistência detectável". Para a medida "mudança do torque passivo de resistência", esses coeficientes variaram de r=0,72 a 0,83 (p<0,004). Os Coeficientes de Correlação Intraclasse (CCIs) obtidos para as confiabilidades intra e interexaminadores variaram de 0,75 a 0,98. CONCLUSÃO: Os testes propostos apresentaram validade e confiabilidades satisfatórias para serem utilizados na prática clínica.
Subject(s)
Female , Humans , Male , Young Adult , Ankle Joint/physiopathology , Muscle Strength Dynamometer , Reproducibility of ResultsABSTRACT
OBJECTIVES: The aim of the study was to investigate the effect of fetal undernutrition on the passive mechanical properties of skeletal muscle of weaned and young adult rats. INTRODUCTION: A poor nutrition supply during fetal development affects physiological functions of the fetus. From a mechanical point of view, skeletal muscle can be also characterized by its resistance to passive stretch. METHODS: Male Wistar rats were divided into two groups according to their mother's diet during pregnancy: a control group (mothers fed a 17 percent protein diet) and an isocaloric low-protein group (mothers fed a 7.8 percent protein diet). At birth, all mothers received a standardized meal ad libitum. At the age of 25 and 90 days, the soleus muscle and extensor digitorum longus (EDL) muscles were removed in order to test the passive mechanical properties. A first mechanical test consisted of an incremental stepwise extension test using fast velocity stretching (500 mm/s) enabling us to measure, for each extension stepwise, the dynamic stress (σd) and the steady stress (σs). A second test consisted of a slow velocity stretch in order to calculate normalized stiffness and tangent modulus from the stress-strain relationship. RESULTS: The results for the mechanical properties showed an important increase in passive stiffness in both the soleus and EDL muscles in weaned rat. In contrast, no modification was observed in young adult rats. CONCLUSIONS: The increase in passive stiffness in skeletal muscle of weaned rat submitted to intrauterine undernutrition it is most likely due to changes in muscle passive stiffness.