An electromyographic (EMG) activity pattern for individual muscles in the gait cycle exhibits a great deal of intersubject, intermuscle and context-dependent variability. Here we examined the issue of common underlying patterns by applying factor analysis to the set of EMG records obtained at different walking speeds and gravitational loads. To this end healthy subjects were asked to walk on a treadmill at speeds of 1, 2,3 and 5 km h(-1) as well as when 35-95% of the body weight was supported using a harness. We recorded from 12-16 ipsilateral leg and trunk muscles using both surface and intramuscular recording and determined the average, normalized EMG of each record for 10-15 consecutive step cycles. We identified five basic underlying factors or component waveforms that can account for about 90% of the total waveform variance across different muscles during normal gait. Furthermore, while activation patterns of individual muscles could vary dramatically with speed and gravitational load, both the limb kinematics and the basic EMG components displayed only limited changes. Thus, we found a systematic phase shift of all five factors with speed in the same direction as the shift in the onset of the swing phase. This tendency for the factors to be timed according to the lift-off event supports the idea that the origin of the gait cycle generation is the propulsion rather than heel strike event. The basic invariance of the factors with walking speed and with body weight unloading implies that a few oscillating circuits drive the active muscles to produce the locomotion kinematics. A flexible and dynamic distribution of these basic components to the muscles may result from various descending and proprioceptive signals that depend on the kinematic and kinetic demands of the movements.

Ivanenko Y.P., Poppele R.E., & Lacquaniti F. (2004). Five basic muscle activation patterns account for muscle activity during human locomotion. THE JOURNAL OF PHYSIOLOGY, 556(1), 267-282 [10.1113/jphysiol.2003.057174].

Five basic muscle activation patterns account for muscle activity during human locomotion

LACQUANITI, FRANCESCO
2004

Abstract

An electromyographic (EMG) activity pattern for individual muscles in the gait cycle exhibits a great deal of intersubject, intermuscle and context-dependent variability. Here we examined the issue of common underlying patterns by applying factor analysis to the set of EMG records obtained at different walking speeds and gravitational loads. To this end healthy subjects were asked to walk on a treadmill at speeds of 1, 2,3 and 5 km h(-1) as well as when 35-95% of the body weight was supported using a harness. We recorded from 12-16 ipsilateral leg and trunk muscles using both surface and intramuscular recording and determined the average, normalized EMG of each record for 10-15 consecutive step cycles. We identified five basic underlying factors or component waveforms that can account for about 90% of the total waveform variance across different muscles during normal gait. Furthermore, while activation patterns of individual muscles could vary dramatically with speed and gravitational load, both the limb kinematics and the basic EMG components displayed only limited changes. Thus, we found a systematic phase shift of all five factors with speed in the same direction as the shift in the onset of the swing phase. This tendency for the factors to be timed according to the lift-off event supports the idea that the origin of the gait cycle generation is the propulsion rather than heel strike event. The basic invariance of the factors with walking speed and with body weight unloading implies that a few oscillating circuits drive the active muscles to produce the locomotion kinematics. A flexible and dynamic distribution of these basic components to the muscles may result from various descending and proprioceptive signals that depend on the kinematic and kinetic demands of the movements.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/09
English
adult; analysis of variance; article; body weight; controlled study; electromyography; factorial analysis; female; gait; gravity; heel; human; human experiment; kinematics; kinetics; leg muscle; locomotion; male; muscle contraction; normal human; oscillation; priority journal; recording; skeletal muscle; treadmill exercise; walking aid; walking speed; waveform; Adult; Biomechanics; Body Weight; Electromyography; Factor Analysis, Statistical; Female; Gait; Humans; Leg; Male; Muscle, Skeletal; Time Factors; Weight-Bearing
Ivanenko Y.P., Poppele R.E., & Lacquaniti F. (2004). Five basic muscle activation patterns account for muscle activity during human locomotion. THE JOURNAL OF PHYSIOLOGY, 556(1), 267-282 [10.1113/jphysiol.2003.057174].
Ivanenko, Yp; Poppele, Re; Lacquaniti, F
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/31201
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