117 healthy Korean, age ranging between 17-58, were evaluated for H-reflex conduction velocities.

The aim of this study is to find a handy and precise method of H-reflex evaluation. E. Johnson has developed the expected normal latencies for the person with same age and same leg length. If one use this method, his patient's H-reflex latency has to be compared with the expected value every time. We thought this is too complicated and have come to think of more simple one.

Findings were following:

1) The coefficient of variation of the H-reflex latency and H-reflex conduction velocity were 112.3% and 8.0%, respectively. Narrower dispersion was obtained in H-reflex conduction velocity than the difference between observed H-reflex latency and expected H-reflex latency using Braddom & Johnson's formula:

H latency(msec)-9.14+0.46 leg length(cm)+0.1 age(year).

1) The coefficient of variation of the H-reflex latency and H-reflex conduction velocity were 112.3% and 8.0%, respectively. Narrower dispersion was obtained in H-reflex conduction velocity than the difference between observed H-reflex latency and expected H-reflex latency using Braddom & Johnson's formula:

H latency(msec)=9.14+0.46 leg length(cm)+0.1 age(year).

2) A formula was obtained by an analysis of the regression of the H-reflex conduction velocity(HCV) on age: HCV(m/sec)=65.28-0.12 age(year)

3) A formula was obtained by an analysis of the regression of the H-reflex conduction velocity(HCV) on height: HCV(m/sec)=3701+0.15 height(cm)

4) A formula was obtained by an analysis of the regression of the H-reflex latency on height: H latency(m/sec)=14.07+0.08 height(cm)

5) A formula was obtained by an analysis of the regression of the height on age: Height(cm)=177.88-0.30 age(cm)

The younger was taller than the older in this group.