•  
  •  
 

Rehabilitation Practice and Science

Translated Title

股四頭肌主動收縮之伸張反射在具不同肌肉張力成人受測者之動態表現

Abstract

Stretch reflex dynamics, including assessment of reflex threshold angle (RTA) and reflex threshold velocity (RTV), has been used for quantitative evaluation for spastic hypertonia. However, neither a reliable clinical scale nor objective instrumental measurement had been developed to quantify clinical hypotonia. The purpose of the present study is to assess stretch reflex dynamics in subjects with different muscle tones, in terms of RTA and RTV to the voluntarily contracted quadriceps femoris muscle .Twenty-four subjects were classified into 3 groups (hypotonic, ”normotonic” or normal, and hypertonic) according to clinical presentation of the muscle tone. Each group consisted of 8 subjects. The lower limbs with abnormal muscle tone and the right lower limbs of normal subjects were tested. Passive stretch of the maximally activated quadriceps muscle at various angular velocities(110, 140, 180, 200, and 240o/sec) was applied by a computer-controlled isokinetic dynamometer (Kin-Com, model 500H). From the angle-time curve, knee joint angle corresponding to the onset time of increased surface electromyographic activity of vastus lateralis was defined as RTA. Then RTV was derived from the velocity-time curve. RTA and RTV in the three groups under 5 differnet velocities of stretch were compared statistically using two-way, repeated measures of ANOVA. Significant difference was noted between the three groups(p＜0.001). Post hoc analysis revealed RTA and RTV in hypotonic group were significantly higher than in normal and hypertonic groups. Under various velocity of stretch, RTV was found to be significantly different within the same group, but RTA showed no difference. From the results, reflex threshold was not constant in a subject, depending on the stretching velocity and muscle tone. The status of muscle tone could be presented by the measures of RTA or RTV. ”Hypotonia” felt by clinical examination in relaxed muscle had not been able to show a decrease in stretch reflex. In our study, stretch reflex threshold was depressed by maximally voluntary muscle contraction. To assess the stretch reflex dynamics in this way, we found that stretch reflex threshold(RTA and RTV) in hypotonic group was significantly larger than both in normal and hypertonic groups. As a result, stretch reflex dynamics of the maximally voluntary contraction of quadriceps muscle could be used to assess the change of muscle tone in subjects with CNS lesions, especially those with hypotonia.

Language

Traditional Chinese

First Page

21

Last Page

29

Download

Share

COinS