Peak torque and knee kinematics during gait after eccentric isokinetic training of quadriceps in healthy subjects / O pico de torque e a cinemática do joelho durante a marcha após treino isocinético excêntrico do quadríceps em sujeitos saudáveis

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.

Indivíduos que apresentam diferença estática entre os joelhos também apresentam diferença durante a marcha? / Do individuals who present a static difference between the knees also present a difference during gait?

CONTEXTUALIZAÇÃO: A articulação do joelho destaca-se por ser uma estrutura comumente afetada por alterações degenerativas, lesões e síndromes. Avaliações clínicas objetivas e precisas são necessárias para estabelecimento de diagnósticos adequados e, conseqüentemente, melhores resultados tanto das cirurgias como dos programas de reabilitação. OBJETIVO: Verificar a presença de diferença entre os joelhos durante a marcha e sua relação com a diferença estática, nos planos sagital e frontal. MÉTODO: Foram avaliados 45 sujeitos saudáveis, sendo 21 do sexo masculino e 24 do sexo feminino. Mediu-se a amplitude de movimento da articulação do joelho, na marcha, por meio da eletrogoniometria. A avaliação da postura estática do joelho foi feita por meio de fotogrametria. Os dados foram analisados descritivamente e aplicou-se o coeficiente de correlação de Pearson. RESULTADOS: Os indivíduos apresentaram valores médios similares para os lados direito e esquerdo (diferença de aproximadamente 0,5º) no registro estático dos planos sagital e frontal. No entanto, o desvio-padrão foi alto, indicando grande variabilidade entre os sujeitos. Para o registro dinâmico, a diferença entre os joelhos foi de 0,4º para o plano sagital e 1º para o plano frontal. No entanto, a variabilidade encontrada também foi alta, principalmente para o plano frontal. Não foi encontrada correlação entre os registros estáticos e dinâmicos nos dois planos de movimento avaliados (r= -0,003 e p= 0,492 para o plano sagital e r= -0,014 e p= 0,465 para o plano frontal). CONCLUSÕES: Embora não tenha sido encontrada relação entre os registros estático e dinâmico, esse assunto merece ser investigado em estudos futuros, avaliando-se grupos mais amplos e com alterações posturais específicas e mais pronunciadas.

INTRODUCTION: The knee joint stands out as a structure that is commonly affected by degenerative alterations, injuries and syndromes. Precise objective clinical evaluations are necessary for establishing appropriate diagnoses and, consequently, better results from both surgical procedures and rehabilitation programs. OBJECTIVE: To investigate the existence of differences between the knees during gait and their relationship with the static difference in the sagittal and frontal planes. METHOD: Forty-five healthy subjects were included, of whom 21 were male and 24 were female. Knee joint range of motion was measured during gait by means of flexible electrogoniometry. The static posture of the knee was evaluated by means of photogrammetry. The data were analyzed descriptively and the Pearson correlation coefficient was applied. RESULTS: The individuals presented mean values that were similar for right and left knees in static recordings of the sagittal and frontal planes (difference of approximately 0.5º). However, the standard deviation was large, thus indicating great variability between the subjects. For the dynamic recordings, the difference between the knees was 0.4º for the sagittal plane and 1º for the frontal plane. The variability found was also large, especially for the frontal plane. There was no correlation between the static and dynamic recordings in the two planes of motion evaluated (r = -0.003 and p = 0.492 for the sagittal plane; r = -0.014 and p = 0.465 for the frontal plane). CONCLUSION: Although no relationship was found between the static and dynamic recordings, this matter deserves investigation in future studies, with evaluations of broader groups with specific and more pronounced postural abnormalities.

Change in knee kinematics during gait after eccentric isokinetic training for quadriceps in subjects submitted to anterior cruciate ligament reconstruction.

Knee kinematics after anterior cruciate ligament (ACL) reconstruction is of interest in studies evaluating the effect of training programs. Many studies have addressed knee flexion/extension but not valgus/varus movements. Considering that joint stability is a major concern in ACL reconstruction surgery, movements occurring in the frontal plane of the knee also deserve attention. Knee extensor torque was analyzed by an isokinetic dynamometer and the angular amplitudes and velocities of flexion/extension and valgus/varus movements were analyzed by goniometry during gait 9 months after ACL reconstruction. The analysis was repeated after 3 months of eccentric isokinetic training of the quadriceps in five patients. The gait pattern was also recorded for 10 healthy controls. The knee extensor torque and flexion/extension range of movement during gait increased significantly after training. However, an unexpectedly increased valgus, most pronounced during the swing phase, which may imply adverse effects on the knee, was also observed in the ACL reconstructed knee. The recorded valgus angles may however be overestimated due to crosstalk. Thus, the extent of the increased valgus, as well as the mechanisms involved and the functional and clinical implications, need clarification before eccentric training after ACL reconstruction can be generally recommended.