Physiological electromyographic activation patterns of trunk muscles during walking

It is well known that, in spite of its crucial role in the posture, locomotion and voluntary movements, trunk hasreceived less consideration from researchers than upper and lower limbs. On the other hand, rehabilitative interventions ofpatients with upper motoneuron syndrome have always been focused firstly on treatment and recovery of trunk’s postureduring standing, sitting and walking.Trunk is a complex anatomical structure and it is composed by a large variety of bones, articulations, ligaments andmuscles. From a functional point of view, trunk muscles have been subdivided into two systems: a local system whichensures stability and a global system which enables movements. Muscles of these two systems work by eccentric andconcentric contractions, according to the functional needs.Surprisingly, in the literature are reported only a few studies regarding the trunk muscle activations during walking. Thesestudies investigated the electromyographic activation patterns in different experimental conditions as walking on awalkway, over a treadmill at different velocities, in water or in deep-water. Furthermore, data analysis was differentlyperformed by analyzing the qualitative and quantitative features of timing and amplitude of electromyographic recordingsfor each muscle or by other more sophisticated methods as cluster analysis or principal components analysis. Finally,some variability has been observed in the normal population also including sex differences. The aim of this review is toshow the state of art of this topic, in normal subjects.Keywords: Surface electromyography, trunk, muscle, gait, ana