View Full Version : EMG onset and cessation

Steve Vankoski
10-02-1996, 01:22 AM
Greetings All:

Typically, in the clinical gait analysis setting, the onset and cessation of
muscle activity is determined by an experienced individual or group of
individuals by viusual inspection of the pattern. These points are
expressed as a percent of the gait cycle , stance phase or swing phase.
Much of the liturature which reports on normal and pathologic gait
electromyographic activity is not clear on the methodology used to determine
the threshold of activity (i.e. percent of maximium voluntary contraction,
percent of maximum magnitude signal during gait cycle, percent of average
magnitude signal over gait cycle or simply by visual inspection by an
experienced clinician). Dr. Sutherland's book The Development of Mature
Walking reports normal onsets and cessations for chilcren and mature gait as
a percent gait cycle without alluding to the method of this determination
(possibly in other references?) Visual inspection is commonplace in daily
clinical application. My question: What are the acceptable methods to
report EMG timing in clincal and scientific settings? Thank you in
anticipation of your responses.

Take care

Steve Vankoski, MS
Children's Memorial Hosiptal
Gait Analysis Laboratory
email: svankoski@nwu.edu