Principal postural acceleration and myoelectric activity: Interrelationship and relevance for characterizing neuromuscular function in postural control

Assessing Walking Stability Based on Whole-Body Movement Derived from a Depth-Sensing Camera

“…In addition, the pre-swing is a transitional period between the stance and swing in which the foot pushes off the ground and lifts off [ 48 ]. Since PM accelerations correlate with lower-limb electromyographic activity [ 14 ], the tighter neuromuscular control (PA 3 _N) observed in females may be interpreted as a sign of how neuromuscular control differs between sexes. In other words, females may need tighter neuromuscular control to maintain weight-bearing stability and move from the stance phase to the swing phase, since the single-limb support of the stance phase involves progressive body movement over the foot’s weight-bearing stability [ 48 ].…”

“…However, one main limitation is that the Kinect V2 kinematic data are not sampled consistently at 30 Hz throughout all studies, requiring resampling the signal at a constant sampling frequency before data processing [ 30 ]. For future research, a combination study of muscle activity and self-specific manners related to walking stability is of interest, since the strength of correlation level between myoelectric activities and principal accelerations (PA k ) differs between muscles, indicating that specific muscles play an important specific role in specific movement components [ 14 ]. Moreover, it may be of interest to focus on the effects of walking speed and external perturbation on walking stability.…”

“…In analogy with Newton’s mechanics, the “ principal accelerations ” (PA k ( t )) can be obtained by differentiating PP k ( t ) twice. PA k ( t ) are reported to be associated with the lower-limb electromyographic (EMG) data in postural control tasks [ 14 ], supporting their effectiveness in assessing neuromuscular control of individual PMs not only observed in balance tasks [ 10 , 32 , 33 , 35 , 39 , 40 ], but also in other types of human movement tasks (e.g., walking [ 12 , 41 ] and running [ 15 ]). The word “ principal ” in the titles of the kinematic variables indicates that these variables were obtained through PCA [ 9 ].…”

“…Individual PMs can be visualized as different movement synergies, resembling the swing phase, stance phase, and other relevant movements, cooperatively forming together to complete the walking tasks [ 12 , 13 ]. PCA-based posture space also provides data on each PM’s position and acceleration [ 9 ], reflecting the neuromuscular control of each PM k in terms of system forces [ 8 , 10 ] and myoelectric activities [ 14 ]. Furthermore, in order to assess the local dynamic stability during gait, LyE has been applied to individual PMs’ positions, reflecting the inherent ability of the neuromuscular system to control infinitesimal perturbations of individual movement components [ 13 , 15 ].…”

The Kinematic and Kinetic Responses of the Trunk and Lower Extremity Joints during Walking with and without the Spinal Orthosis

“…Body posture shows the interrelationship of human muscles, nervous system, bones, and internal organs [ 1 , 2 ]. Normal posture refers to the head in a normal position (not leaning forward, backward, laterally, or twisted), the cervical vertebrae, thoracic vertebrae, and lumbar vertebrae are in normal curvature, the pelvis and hip joints are in a normal position (not abducted or adducted), and the ilium and pubic symphysis are in the same plane [ 3 ].…”