Period-amplitude analysis of EMG from slow and fast extensors of cat during locomotion and jumping.
A real-time period-amplitude analysis program for EMG involving the detection of events consisting of the period and amplitude difference between maxima and minima was used to study the activity patterns of fast and slow, hind and forelimb extensors during treadmill locomotion and jumping. Events were stored in a two-dimensional table providing an easily interpreted quantification of frequency and amplitude parameters of single EMG bursts which were characterized over a range of movements by the mean frequency and amplitude. Periods between zero crossings of the original signal were also stored. Both mean frequency and mean amplitude remained relatively steady for the slow extensors throughout the range of movements, while the fast extensors exhibited an increase in both mean frequency and mean amplitude during the same movements. The results show that fast extensors of the hind and forelimb follow the kinetic demands of the movement, while the activity pattern of the slow extensors is constant and independent of the movement kinetics. Slight discontinuities in these trends are discussed in their possible relation to the dynamics of msucle recruitment. Period-amplitude analysis provides a useful method of quantifying the raw EMG while retaining much of the original information of the signal.
D000818:Animals; D002415:Cats; D004576:Electromyography; D005552:Forelimb / Q000502:physiology; D006614:Hindlimb / Q000502:physiology; D009043:Motor Activity / Q000502:physiology*; D009119:Muscle Contraction