Abnormal EMG muscle activity during gait in patients without neurological disorders

Abnormal muscle activity in patients with a central neurological disorder is commonly attributed to the underlying condition. This study considered abnormal muscle activity in orthopaedic patients who had no neurological involvement. Thirty-nine patients with a variety of orthopaedic problems underwent gait analysis, which included measurement of passive range of motion at the legs, manual muscle strength testing (MMST), instrumented gait analysis, and surface electromyography (EMG). Abnormal timing and duration of EMG activity was found in 51/77 legs. Muscle weakness was the most important cause of the abnormal EMG activity (p>0.001). However, abnormal muscle activity did not correspond to the joint which was controlled by the weak muscles. The triceps surae muscle, represented by the medial gastrocnemius, was significantly more involved (68.6%). Co-activity of the knee extensors and hamstrings was found in 17% of the affected legs. Three out of the 51 legs showed a continuous activity of the rectus femoris muscle in swing. These findings illustrate mechanisms to compensate for muscle weakness in stance in neurologically intact subjects

Effects of plantarflexion on pelvis and lower limb kinematics

Modelling the effect of soleus and gastrocnemius contractions against the floor resistance in a forward dynamics simulation revealed that hip flexion, internal rotation and adduction together with external pelvic rotation could be attributed to a direct, but distant effect of triceps surae contraction. Knee flexion smoothed out the effect. To validate this clinically relevant biomechanical observation, ankle plantar flexion was correlated with hip and pelvic rotation retrospectively in children with spastic cerebral palsy. In 49 children with spastic hemiplegia, plantar flexion showed a significant correlation with increased pelvic retraction and hip internal rotation. In contrast, in 47 children with spastic diplegia no significant effect of the triceps surae on hip and pelvis kinematics was found. Bilateral hip and knee flexion in diplegia appeared to prevent the proximal effect of the triceps surae seen in the hemiplegics. In diplegia triceps surae overactivity did not appear to be a significant cause of internal rotation gait

Effects of Plantarflexion on Pelvis and Lower Limb Kinematics.

Modelling the effect of soleus and gastrocnemius contractions against the floor resistance in a forward dynamics simulation revealed that hip flexion, internal rotation and adduction together with external pelvic rotation could be attributed to a direct, but distant effect of triceps surae contraction. Knee flexion smoothed out the effect. To validate this clinically relevant biomechanical observation, ankle plantar flexion was correlated with hip and pelvic rotation retrospectively in children with spastic cerebral palsy. In 49 children with spastic hemiplegia, plantar flexion showed a significant correlation with increased pelvic retraction and hip internal rotation. In contrast, in 47 children with spastic diplegia no significant effect of the triceps surae on hip and pelvis kinematics was found. Bilateral hip and knee flexion in diplegia appeared to prevent the proximal effect of the triceps surae seen in the hemiplegics. In diplegia triceps surae overactivity did not appear to be a significant cause of internal rotation gait

Quantitative analysis of upper limbs during gait: a marker set protocol

To develop a marker set for simultaneously assessing upper and lower limb biomechanics during gait.; 24 healthy young subjects (mean age: 23.80 years) were assessed quantitatively using an optoelectronic system, two force platform and a video system. Passive markers were positioned according to the proposed marker set which enables acquiring the upper and lower limb movement simultaneously during Gait Analysis. In addition to the traditional parameters obtained from Gait Analysis, the shoulder and elbow angles were computed from markers coordinates of upper limbs; then, some significant parameters were identified and calculated. From shoulder and elbow position, angles, angular velocities, angular acceleration, moments, and powers were calculated for shoulder and elbow joints.; Kinematic and kinetic data were obtained in the three planes (sagittal, frontal, and transversal) for the shoulder and in the sagittal plane for the elbow. Normative ranges were obtained for these parameters from data of healthy participants.; The proposed experimental set-up enables simultaneous assessment of upper and lower limb movement during gait. Thus, no further trials are required in addition to those acquired during standard gait analysis in order to assess upper limb motion, which also makes the experimental set-up feasible for clinical applications

Restoring a heel-to-toe gait pattern does not influence spinal kinematics in patients with hemiplegic cerebral palsy

Introduction: Foot equinus and leg length discrepancy (LLD) are common problems in patients with hemiplegic cerebral palsy (hCP), each causing secondary deviations of pelvic motion during gait [1–3]. It is therefore plausible that the deviations in spinal kinematics observed in hCP patients occur secondarily as a compensation arising from the disturbed leg function and the associated changes in the position of the pelvis. Research question: Does the correction of lower extremity function by orthotics (ankle-foot-orthosis and heel lift) have an effect on spinal gait kinematics in hCP patients? Methods: A total of 10 adolescent hCP patients and 15 healthy controls participated in this study. Participants were equipped with 56 reflective markers (combination of Plug-in-Gait full body and IfB marker sets) and measured during barefoot walking at a self-selected speed using a 12-camera motion analysis system (Vicon). Patients then wore shoes with orthotic corrections on the affected side and were measured again. Thoracic and lumbar spinal curvature angles in the sagittal and frontal planes (primary outcomes) as well as segmental trunk, lower extremity joint angles, and spatio-temporal gait parameters (secondary outcomes) were extracted and parameterized accordingly. Comparisons between populations and conditions were conducted using oneway analyses of variance with Tukey post hoc tests and effect sizes. To evaluate the clinical relevance of a difference, a minimal clinically important difference (MCID) of 58 was used for the angles. Results: The pathological toe-walking gait pattern during the barefoot condition was corrected into a normal heel-to-toe gait pattern when walking with the orthotic corrections. However, this seemed not to influence spinal or general trunk kinematics. Differences could only be found between the hCP patients and the healthy controls (see Figure). Discussion: Spinal gait deviations in adolescent patients with mild forms of hCP seemed to occur not as a secondary effect of a spastic equinus foot or an LLD but due to proximal abnormalities such as hip flexor contractions, which might have been long-term structural adaptations due to passive secondary effects of foot deformity. The question remains, however, whether lower extremity orthotics in younger patients and/or more severe cases of hCP would have different effects on spinal kinematics. In addition, all patients were used to walking with orthotics and might therefore have already adapted their barefoot walking pattern such that possible effects of orthotics have been diluted. Future research should consider investigating long-term effects of orthotics as well as the relation between spinal kinematics and disease severity. References [1] Brunner R, et al. Gait Posture 2008;28:150–6. [2] Goodman MJ, et al. Gait Posture 2004;20:238–44. [3] Aiona M, et al. J. Pediatr. Orthop. 2015;35:280–4