Effects of electrical muscle stimulation combined with voluntary contractions after knee ligament surgery.

The aim of the present study is to compare the effect of electrical muscle stimulation combined with voluntary muscle contractions with a program only with voluntary muscle contractions during immobilization in casts after anterior cruciate ligament surgery. Twenty-three patients, 7 women and 16 men with a mean age of 28 yr, were randomized into two groups: an experimental group (13 patients) and a control group (10 patients). Post-operatively, the patients were immobilized for 3 wk in a full leg cast with the knee flexed at an angle of 20 degrees to 30 degrees and then in a knee cast for another 3 wk. All patients had a standard program with quadriceps muscle contractions. In addition, the experimental group received electrical stimulation of the quadriceps muscle 4 X 10 min, 3 times.wk-1, at a frequency of 30 Hz. During each stimulation, the patients were requested to contract the quadriceps muscle voluntarily as well. When pre-operative measurements were compared with those at the end of the immobilization period (6 wk after the operation), a significantly larger reduction in the knee extension isometric muscle strength was found for the control group than for the experimental group. In comparisons of the data of the male subjects only, this difference was still seen to be significant. The cross-sectional area of the quadriceps muscle measured with computed tomography was significantly less reduced during the immobilization period in the experimental group than in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of high- and low-frequency muscle stimulators.

Electrical stimulation of the quadriceps muscle with a high-frequency since wave stimulator (Electro-Stim 180) and a low-frequency rectangular wave stimulator (Respond II) was compared in 15 physiotherapists. The maximal tolerable stimulation intensity was given for 30 stimulation periods, and the isometric torque produced was measured on a Cybex dynamometer. Maximal voluntary isometric contractions were recorded immediately before and after the stimulation sessions and showed a significant reduction after stimulation, with no difference between the two stimulators. There was no significant difference between the stimulators in the amount of torque produced. The torque during stimulation with Electro-Stim 180 showed a larger variability than with Respond. With both stimulators there was a decrease in the torque produced with an increase in number of contractions. There was no qualitative or quantitative difference between the two stimulators in the perceived discomfort. The low-frequency stimulator has a theoretical advantage because of its constant current principle and more constant stimulation effect.

Muscle function and morphology in myotonic dystrophy.

Patients with myotonic dystrophy classified clinically into function groups were studied. Muscle strength for knee extension and flexion was, with few exceptions, moderately or markedly reduced with successively more severe clinical disability. The reduction in maximal walking speed showed a similar tendency. There was a large percentage of both type I and in relation to normal findings of type II C fibers in biopsies from most patients. The fiber area varied greatly even in the patients in the best function groups, some of whom had large type II fibers. The most common-histopathological changes, found in all function groups, were fiber atrophy with small angular fibers, internal nuclei, splitting, fibrosis and moth-eaten fibers. A high percentage of type I fibers can already be seen in patients with practically no other morphological changes and without significant functional deterioration.