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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in posture with age are of concern because of their association with impaired mobility and the possibility of falls. In this study alignment of the joint centers and balance of body segments were measured in 41 women, aged 65 and older, and correlated with weight, age, change in height, and activity. Balance was assessed by calculating the whole-body center of gravity, and the partial centers of gravity above the knee and hip. Compared to a younger reference population, the older subjects had greater kyphosis, a more posterior hip position, and leaned forward more from the hips (more anterior center of gravity above the hips). Among the 41 elderly subjects, larger kyphoses correlated with greater decrease in height. Elderly subjects who were inactive tended to learn more, but forward lean was not correlated to other variables. These findings suggest two separate sets of changes: an osteoporosis-related stooping, and also a forward lean that may relate to muscular weakness or to fear of instability. Posture among the elderly was quite varied and did not follow any one pattern of change.
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PMID:Changes in posture and balance with age. 142 Apr 5

Hip deformities in walking patients with cerebral palsy are rare. Nineteen diplegic and four hemiplegic patients with unilateral hip subluxation were studied to determine whether or not characteristic gait patterns could be identified. All were examined clinically and radiologically as well as undergoing observational and instrumented three dimensional gait analysis. Twenty one of the patients compensated for the subluxation with an ipsilateral trunk lean and contralateral pelvic drop. These patterns were quantified in the kinematic and kinetic variables measured. We conclude that hip abductor weakness should be considered as the cause of the deformity.
Gait Posture 2000 Apr
PMID:Hip deformities in walking patients with cerebral palsy. 1089 61

The purpose of this study was to identify biomechanically the mechanisms adopted by Chinese men when they psychophysically determined their MAWLs (maximum acceptable weights of lift) in different tasks. Twenty-two healthy Chinese men determined their MAWLs at two lifting vertical ranges and three lifting frequencies. Peak L5/S1 compressive forces, elbow and shoulder peak reactive moments, acceleration effects, and postures were analyzed throughout the lifting acts. The results showed that different lifting techniques were adopted when determining the MAWL at different vertical ranges and frequencies of lifting. Posture analyses showed that a more stooped technique was used in frequent tasks, which would minimize the metabolic cost. For infrequent tasks, subjects accelerated and lifted the load upward and then shortened the moment arm by flexing the elbow and shoulder joints during landing, to compensate for weakness of the upper extremities. The high prelifting acceleration used during the infrequent tasks caused high compressive forces on the L5/S1 disc. These results emphasize the importance of considering the roles of upper extremity strength when designing lifting tasks for Chinese workers.
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PMID:Optimal lifting techniques adopted by Chinese men when determining their maximum acceptable weight of lift. 1107 15

Eight children with lumbo-sacral myelomeningocele (MMC) underwent three-dimensional movement analysis to determine whether or not differing levels of lower extremity strength affected the extent of shoulder, trunk and pelvis movement during independent walking when wearing orthoses. Fourteen control children were also investigated. The patterns of upper body movements in all MMC children were well defined and consistent, showing small standard deviations from the mean. In the frontal and transverse planes, segment displacements of the MMC children assigned into Group II (hip extensor and abductor muscle strength grade 0-2) were almost twice that of the MMC children in Group I (hip extensor and abductor muscle strength grade 3-4). All segment displacements in the frontal, transverse and sagittal planes for Group I and Group II children were significantly greater than those for the controls. In the frontal plane these differences were approximately 4-10 times greater, with the Group II children having the largest peak-to-peak displacements. These results indicate that the motion amplitudes of the upper body segments are related to the degree of muscle weakness of the lower limbs. No significant differences were found when comparing segment motions during walking with either the Ferrari type knee-ankle-foot or ankle-foot orthoses.
Gait Posture 2002 Apr
PMID:Upper body movement during walking in children with lumbo-sacral myelomeningocele. 1186 5

Nine subjects (12 sides) with cerebral palsy who walked in equnius were evaluated prior to and 1 year after surgical tendo Achilles lengthening. Gastrocnemius and soleus length [Gait Posture, 6 (1997) 9] and plantarflexor force [Gait Posture, 6 (1997) 9; J Biomech, 23 (1990) 495] were calculated. The length of the gastrocnemius and soleus increased significantly (P<0.01) following the intervention. Force output of the triceps surae during push-off increased significantly (13.95 N/kg body weight (BW) preop to 30.31 N/kg BW postop; P<0.01). Assessment of the force-length capacity of the triceps surae in candidates for tendo Achilles lengthenings may identify individuals at risk of residual weakness and iatrogenic crouch.
Gait Posture 2002 Apr
PMID:Length and force of the gastrocnemius and soleus during gait following tendo Achilles lengthenings in children with equinus. 1186 6

This study evaluated the effects of medial hamstring lengthening on gait in patients with diplegic cerebral palsy. A group of patients who underwent medial hamstring lengthening and distal rectus transfer was compared to a group of patients who underwent intramuscular psoas lengthening as well. Patients who underwent a psoas lengthening showed an increased anterior pelvic tilt and a tendency towards genu recurvatum, features that could indicate postoperative hamstring weakness. These results underline the importance of medial hamstrings for pelvis and knee motion in the sagittal plane during walking. In additional the limitations of the popliteal angle as a clinical measure to evaluate hamstring length in the presence of hip flexor tightness are discussed.
Gait Posture 2002 Dec
PMID:Medial hamstring lengthening in the presence of hip flexor tightness in spastic diplegia. 1244 54

This paper focuses on the contributions of the gluteus maximus, biceps femoris, gastrocnemius and soleus in maintaining the stability of the stance limb in the sagittal plane during the mid-stance phase of gait. In the absence of any one of these muscles, the potential compensatory changes in muscle activation are explored, the aim being to restore stability to the stance limb. The investigation was carried out by integrating musculoskeletal modelling, forward simulation and optimization techniques. We concluded that maintenance of stance limb stability requires a subtle interplay of muscle activations. Weakness in a single muscle is unlikely to be adequately compensated for by increasing or decreasing the activation of one muscle alone.
Gait Posture 2003 Jun
PMID:The complementary role of the plantarflexors, hamstrings and gluteus maximus in the control of stance limb stability during gait. 1277 Jun 40

The movement of the centre of mass in the vertical and lateral directions during gait in children with myelomeningocele was analyzed. The children were classified into five groups depending on the successive paresis of lower limb muscle groups and compared to a control group. In the groups with dorsi- and plantarflexor weakness, the excursions increased and an anterior trend in the centre of mass was observed. In the groups with additional abductor paresis, the lateral excursion was highest and the vertical excursion low due to increased transverse and frontal motion and reduced sagittal motion. With further paresis of the hip extensors, the centre of mass was more posteriorly positioned due to compensatory trunk extension. Improved understanding of individual children's solutions to their muscle paresis can be obtained by visualizing the centre of mass relative to the pelvis. Centre of mass analyses in myelomeningocele offer an important complement to standard gait analysis.
Gait Posture 2003 Oct
PMID:Centre of mass motion during gait in persons with myelomeningocele. 1465 6

This study was performed to investigate whether elderly patients with imbalance can be distinguished from healthy elderly subjects by comparing their whole body center of mass (COM) motion in the medio-lateral (M-L) direction during obstacle crossing. Nine healthy elderly adults and six elderly patients having complaints of 'dizziness' or 'unsteadiness' during walking (three with bilateral/unilateral vestibular weakness and three with unclear diagnosis) were recruited to perform unobstructed level walking and crossing of obstacles set to 2.5, 5, 10 and 15% of each subject's height. Kinematics of the COM was calculated using a weighted sum average of a 13-segment biomechanical model. There were no significant group differences for the temporal-distance gait parameters during all testing conditions. However, elderly patients with balance disorders demonstrated significantly greater and faster lateral motion of the COM when crossing over obstacles. These measurements distinguish elderly patients with imbalance from healthy elderly subjects. Furthermore, the increased M-L motion of the COM during obstacle crossing showed a positive correlation with an increased M-L range of motion of the swing foot trajectory. This increase in M-L motion indicates a compensatory adjustment in the swing foot trajectory to land the swing foot at an appropriate location that would establish a new base of support to counter the balance disturbance in the frontal plane.
Gait Posture 2003 Dec
PMID:Medio-lateral motion of the center of mass during obstacle crossing distinguishes elderly individuals with imbalance. 1466 45

Thirty self-ambulatory children with mid-lumbar to low-sacral myelomeningocele who walked without aids and 21 control children were evaluated by three-dimensional gait analysis. Characteristic kinematic patterns and parameters in the trunk, pelvis, hip, knee and ankle were analyzed with respect to groups with successive weakness of the ankle plantarflexor, ankle dorsiflexor, hip abductor, hip extensor and knee flexor muscles. Extensive weakness of the plantarflexors resulted in kinematic alterations in the trunk, pelvis, hip and knee and in all three planes seen as knee flexion, anterior pelvic tilt and trunk and pelvic rotation. Additional extensive weakness of the dorsiflexors made little difference in the walking strategy. Large kinematic alterations in all planes were observed where there was a large extent of additional weakness of the hip abductor but strength remaining in the hip extensors. In this group, gait was characterized by large lateral sway of the trunk, rotation of the trunk and pelvis, pelvic hike and increased extension of the knees. In the group with total poresis hip extensors but yet some knee flexion, gait was similar to the previous group but there was less sagittal plane movement greates and posterior trunk tilt. Gait analysis provides an understanding of the compensatory strategies employed in these patients. Clinical management can be directed towards stabilizing the lower extremities and accommodating large upper body motion to preserve this method of self-ambulation even in children who have considerable hip extensor and abductor weakness.
Gait Posture 2003 Dec
PMID:Characteristic gait kinematics in persons with lumbosacral myelomeningocele. 1466 50


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