Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology
-
J Electromyogr Kinesiol · Aug 2018
Trunk postural adjustments: Medium-term reliability and correlation with changes of clinical outcomes following an 8-week lumbar stabilization exercise program.
Low back pain (LBP) has been previously associated with delayed anticipatory postural adjustments (APAs) determined by trunk muscle activation. Lumbar stabilization exercise programs (LSEP) for patients with LBP may restore the trunk neuromuscular control of the lumbar spine, and normalize APAs. This exploratory study aimed at testing the reliability of EMG and kinematics-based postural adjustment measures over an 8-week interval, assessing their sensitivity to LBP status and treatment and examining their relationship with clinical outcomes. ⋯ Future clinical trials are needed to target patients with and without delayed APAs at baseline and to explore the sensitivity of different outcome measures related to APAs. Different tasks more challenging to postural stability may need to be explored to more effectively reveal APA dysfunction.
-
J Electromyogr Kinesiol · Feb 2018
Standing on a sliding board affects generation of anticipatory and compensatory postural adjustments.
Postural control is compromised in the presence of body instability. We studied anticipatory and compensatory postural adjustments people use to maintain balance while standing on an unstable surface and performing voluntary arm movements. Nine healthy participants stood on a sliding board (that was either locked and as such motionless or unlocked and as such free to move in the anterior-posterior direction) and performed fast bilateral arms flexion. ⋯ Larger maximum COP displacement was seen when participants stood on the locked board. The results demonstrated that when standing on a free to move sliding board and performing bilateral arm flexion, the central nervous system (CNS) does not slow down the arm movements; instead it modifies activation of the lower extremity muscles. The observed differences in APAs and CPAs between the locked and unlocked conditions suggest that the CNS employs similar strategy while controlling the focal part of the task and adjusts the activity of muscles that are close to the source of instability to control postural task.
-
J Electromyogr Kinesiol · Aug 2017
Effects of amplitude and predictability of perturbations to the arm on anticipatory and reactionary muscle responses to maintain balance.
Disturbances to balance arising from forces applied to the upper limb have received relatively little attention compared to disturbances arising from support surface perturbations. In this study we applied fast ramp perturbations to the hand in anterior, posterior, medial and lateral directions. The effects of perturbation predictability and amplitude on the postural response of upper limb, trunk and lower limb muscles were investigated. ⋯ However, the slope of the relation between perturbation amplitude and the magnitude of the change in muscle activation was greater when perturbations were predictable than when they were randomly selected. The timing of both the anticipatory and reactionary increases in muscle activation was invariant across perturbation amplitudes. The characteristics of the reactionary responses have a similar organization to the long latency muscle responses to support surface perturbations.
-
J Electromyogr Kinesiol · Jun 2017
The relationship of corticospinal excitability with pain, motor performance and disability in subjects with chronic wrist/hand pain.
There is a growing body of evidence of changes in corticospinal excitability associated with musculoskeletal disorders, however there is a lack of knowledge of how these changes relate to measures of pain, motor performance and disability. An exploratory study was performed utilizing Transcranial Magnetic Stimulation to investigate differences in corticospinal excitability in the Abductor Pollicis Brevis (APB) between 15 pain-free subjects and 15 subjects with chronic wrist/hand pain and to determine how corticospinal excitability was associated with measures of pain (visual analog scale, AUSCAN™), hand motor performance (isometric and key pinch strength, Purdue Pegboard Test), disability (AUSCAN™), and spinal motoneuronal excitability. ⋯ Changes in corticospinal excitability were significantly correlated with pain intensity (r=0.77), disability (r=0.58), and negatively correlated with motoneuronal excitability (r=-0.57). Corticospinal excitability in subjects with heterogeneous injuries of the wrist/hand was associated with disability and pain.
-
J Electromyogr Kinesiol · Apr 2017
Analysis of 3D multi-segment lumbar spine motion during gait and prone hip extension.
Modeling the lumbar spine as a single rigid segment does not consider the relative contribution of regional or segmental motion that may occur during a task. The current study used a multi-segment model to measure three-dimensional (3D) upper and lower lumbar spine motion during walking and prone hip extension (PHE). The degree of segmental redundancy during these movements was assessed by calculating the cross-correlation of the segmental angle time series (R0) and the correlation of the segmental ranges of motion (RROM). ⋯ Non-significant RROM were demonstrated for all other planes and movements. These results suggest the motion patterns of the upper and lower lumbar regions during walking and PHE are sufficiently distinct to warrant the use a multi-segment model for these movements. It also appears that the degree of redundancy between the upper and lower lumbar regions may be task-dependent.