Effects of muscle strengthening and physical conditioning training on temporal, kinematic and kinetic variables during gait in chronic stroke survivors.

The purpose of this study was to evaluate the impact of a combined program of muscle strengthening and physical conditioning on gait performance in subjects with chronic stroke, using a single group pre- and post-test design. Thirteen subjects were recruited for the 10-week program (3 days/week), which consisted of warm-up, aerobic exercises, lower extremity muscle strengthening and cool-down. Data from cinematographic film and a force plate obtained during multiple walking trials were used in a four-segment kinetic model to yield spatiotemporal, kinematic and kinetic variables. Gait analysis revealed that the 10 week training resulted in significant increases in gait speed associated with improvements in walking patterns as determined by increases in selected kinematic and kinetic measures. After training, subjects were able to generate higher levels of powers and demonstrated increases in positive work performed by the ankle plantar flexor and hip flexor/extensor muscles.

Serial casting in idiopathic toe-walkers and children with spastic cerebral palsy.

Serial casting to stretch the plantar-flexors has been advocated for idiopathic toe-walkers (ITW) and children with spastic cerebral palsy (CP), although outcomes have not been well studied. Neuromuscular function and gait were examined in eight children with CP (mean age, 7.1 years) and eight ITW (mean age, 7.5 years) casted for 3 to 6 weeks. Baseline comparisons indicated that children with CP produced lower isometric plantar-flexor torques (p<0.02) concomitant with marked co-contraction (p<0.001). greater ankle mobility (p<0.02), and higher reflex excitability (p<0.001) than ITW. After casting, both groups increased dorsiflexion range (p<0.001), decreased resistance to passive stretch (p<0.005), and produced maximal plantar-flexor torques in dorsiflexed positions (p<0.001). Reflex excitability was reduced in CP (p<0.05). Immediately postcasting, no children toe-walked, but two with CP resumed a digitigrade pattern 6 weeks later. Gait velocity and stride length did not change (p>0.05). Serial casting yielded positive outcomes that may be longer lasting in ITW.

Muscle strengthening and physical conditioning to reduce impairment and disability in chronic stroke survivors.

OBJECTIVE: To evaluate the impact of a program of muscle strengthening and physical conditioning on impairment and disability in chronic stroke subjects. DESIGN: A randomized pretest and posttest control group, followed by a single-group pretest and posttest design. SUBJECTS: Thirteen community-dwelling stroke survivors of at least 9 months. INTERVENTION: A 10-week (3 days/week) program consisting of a warm-up, aerobic exercises, lower extremity muscle strengthening, and a cool-down. MAIN OUTCOME MEASURES: Peak isokinetic torque of the major muscle groups of the affected lower limb, quadriceps and ankle plantarflexor spasticity, gait speed, rate of stair climbing, the Human Activity Profile (HAP), and the Nottingham Health Profile (NHP) were recorded twice for the treatment group and three times for the control group. RESULTS: Significant improvements were found for all the selected outcome measures (HAP, NHP, and gait speed) for the treatment group (p < .001). In terms of overall training effects, the 13 subjects demonstrated increases in strength of the affected major muscle groups, in HAP and NHP profiles, and in gait speed and rate of stair climbing without concomitant increases in either quadriceps or ankle plantarflexor spasticity. CONCLUSIONS: The 10-week combined program of muscle strengthening and physical conditioning resulted in gains in all measures of impairment and disability. These gains were not associated with measurable changes of spasticity in either quadriceps or ankle plantarflexors.

Multivariate examination of data from gait analysis of persons with stroke.

BACKGROUND AND PURPOSE: Gait analyses yield redundant information that often is difficult to interpret. The purpose of this study was to show how principal-component analysis can provide insight into gait data obtained from persons with stroke. SUBJECTS: Twenty male and 11 female adults who were ambulatory were studied (mean age = 60.5 years, SD = 11.8, range = 24-79; mean time since stroke = 11.4 months, SD = 15.4, range = 2.0-88.0). METHODS: Spatial data were used in a 4-segment link-segment model to calculate the kinematic and kinetic variables of gait. Principal components were constructed on the averages for 40 variables. RESULTS: The first principal component was related to speed and accounted for 40.8% of the variance. The second principal component was related to differences between the 2 limbs (symmetry) and accounted for 12.8% of the variance. The third principal component was related to adoption of a postural flexion bias and accounted for 10.2% of the variance. The fourth principal component, which was not interpretable, accounted for 6.8% of the variance. CONCLUSION AND DISCUSSION: The principal-component analysis allowed clustering of related variables and simplified the complex picture presented by the large number of variables resulting from gait analysis. Examination of variables closely related to each principal component yielded insight into the nature of the strategies used in walking and their interrelationships. The method has potential for insight into similarities and differences in gait performances arising from different pathologies and for comparing the progress of individuals with similar pathologies.

The mobility needs of women with physical disabilities in India: a functional perspective.

The purpose of this research was to explore the functional mobility needs of women with lower extremity disabilities in Gujarat state, India. Ten women participated in a Mobility Needs Assessment which used multiple data collection methods to gather quantitative and qualitative information in five main areas. The results indicated that the physical environment was diverse, at times unpredictable, and environmental barriers were commonly encountered. The women travelled relatively long distances to perform self-care activities such as bathing and toileting. Furthermore, the women had compensated for their disability by implementing different strategies, such as four methods of locomotion, ten sitting positions, and various methods for carrying objects. Activities of daily living were similar amongst the women, although some women required assistance to complete specific activities successfully. Although the women expressed different views on how they felt about their present level of mobility, all were able to identify activities they wished to perform if they could move more easily. The resulting information contributed towards an area where little has been documented previously.

Relationship between alignment and kinematic and kinetic measures of the knee of osteoarthritic elderly subjects in level walking.

Eleven osteoarthritic elderly subjects were tested to analyse the relationships between static radiographic alignment and dynamic kinematic and kinetic measures at the knee in gait. A standard precision radiograph procedure (QPR) was used to measure the static lower limb alignment in two planes and a 3D optoelectronic system was used to measure the biomechanical performance of the knee in level walking. Relationships were calculated between the static radiographic angular measures and the dynamic knee angular measures, dynamic knee joint forces, and dynamic knee moments of force during gait. The results indicated that there was not a close relationship between lower limb alignment and the force estimates in gait. However, a closer relationship was observed between QPR parameters, dynamic knee joint angles, and joint moments in gait, implying that complex interrelationships may exist between static alignment, dynamic alignment, and dynamic kinetic measures. These findings suggest that the static alignment measures associated with both the kinematic and kinetic measures should be combined to better explain the biomechanical changes at the knee joint. RELEVANCE:--Values for radiograph alignment and dynamic variables obtained during walking for a group of elderly subjects with moderate osteoarthritis are provided. Joint forces obtained during walking were not related to static radiographic alignment. The findings indicate that both the coronal and sagittal plane measures were associated with the magnitude of joint moments, joint angles, and timing of the events.

Temporal, kinematic, and kinetic variables related to gait speed in subjects with hemiplegia: a regression approach.

BACKGROUND AND PURPOSE: The gait speed that a patient selects is a well-known indicator of overall gait performance. The purpose of this study was to use multiple linear regression to assess the strength of association of temporal, kinematic, and kinetic gait variables with high walking speeds in patients with hemiplegia. SUBJECTS: Thirty-two subjects (20 male, 12 female) with an average age of 61 years took part in a sagittal-plane gait study of both sides of the body. METHODS: Data from cinematographic film and a force plate obtained during multiple walking trials were used in a seven-segment link-segment kinetic model of the walking subject to yield temporal, kinematic, and kinetic variables. RESULTS: Variables correlating significantly with self-selected speed included the maximum hip extension angle and the maximum hip flexion moment on the affected side, and the maximum ankle and hip powers on both sides. A stepwise regression identified variables most useful in predicting stride speed. For the affected side, these variables were the hip flexion moment, the ankle moment range, the knee moment range, and the proportion of double support. Together these variables explained 94% of the variation in gait speed. On the unaffected side, the variables were the percentage of stance phase, the maximum ankle power (push-off), and the maximum hip power (pull-off). They explained 92% of the variation in gait speed. CONCLUSION AND DISCUSSION: These results suggest that experimental studies are needed to assess the effects of treatment aimed at increasing ankle power and hip power and at decreasing the stance time on the affected side, and that these studies should be directed at obtaining a larger hip flexion moment and a larger ankle moment range on the unaffected side.

Relationships between alignment, kinematic and kinetic measures of the knee of normal elderly subjects in level walking.

Twelve normal elderly subjects were tested to analyse the relationships between static radiographic alignment and dynamic kinematic and kinetic measures at the knee in gait. A standard precision radiograph was used to measure the static lower limb alignment and a 3D optoelectric system was used to measure the biomechanical performance of the knee in level walking. Relationships were calculated between static radiographic angular measures and dynamic knee angular measures, dynamic knee joint forces, and dynamic knee joint moments during gait in corresponding motion planes; and between dynamic knee angular measures and dynamic knee joint forces and dynamic knee moments during gait and in corresponding motion planes. The results showed that the static lower-limb alignment measures did not closely correlate with the kinetic measures of the knee in gait although about half of the static angular alignment measures were significantly related to some of the dynamic knee angular measures. Instead, six of nine dynamic angular measures of the knee were significantly related to the dynamic forces and moments of force in the corresponding motion planes. These results suggest that static alignment measures alone at the present time are not sufficient to predict the dynamic knee joint forces in intact knees.

Feedback of ankle joint angle and soleus electromyography in the rehabilitation of hemiplegic gait.

A computer-assisted feedback system was developed to present to walking subjects instantaneous feedback of their muscle activity or joint angular excursions during gait. Targets for muscle activity or joint motion were displayed on the feedback screen along with timing cues that prompted muscle activity or joint flexion/extension at specific times during the gait cycle. The purpose was to compare the effectiveness of joint angle and electromyographic (EMG) feedback to a focused program of physical therapy for gait. Eight hemiplegic stroke patients were treated with ankle joint angle feedback, EMG biofeedback from the soleus muscle, and conventional physical therapy for gait in a three-period crossover design. PT was given either first or last in the sequence of treatments. Gait analysis prior to and following each type of treatment revealed that the feedback treatments resulted in significant increases in stride length and walking velocity and in positive changes in push-off impulse, gait symmetry, and standing weight-bearing symmetry, as evaluated in a general linear model and paired t-tests. Overall, physical therapy produced no significant changes. However, when physical therapy was the first treatment of the sequence, significant increases in stride length and velocity were observed. When physical therapy was last, there were significant negative changes in gait symmetry and standing weight-bearing symmetry, and negative trends in stride length, walking velocity, and push-off impulse. It is concluded that computer-assisted feedback is an effective tool for retraining gait in stroke patients.

Stairclimbing kinematics on stairs of differing dimensions.

The purpose of this study was to provide a kinematic description of the task of stair ascent and descent. Fifteen women were divided into short, medium, and tall subject groups. Three testing staircases of different riser and tread dimensions were used. Temporal and cinematographic data were collected simultaneously via switchmats and a high-speed camera, respectively. Measures of stairclimbing gait cycle duration, swing and stance phase durations, cadence, and velocity appeared to be systematically related to subject height. Stance (19% to 64%) and swing (36% to 81%) phase durations varied considerably depending on stair dimensions during stair descent. Less variation was observed in stance (50% to 60%) and swing (40% to 50%) values during tasks of stair ascent. Individuals appeared to adjust to stair dimensions by varying the flexion/extension patterns of the knee rather than those of the ankle or hip. Depending on the staircase climbed, knee flexion angles ranging from 83 degrees to 105 degrees were required. Stair dimensions, therefore, appeared to influence the temporal and angular kinematics of the lower limb during stairclimbing.

First metatarsophalangeal joint reaction forces during high-heel gait.

First metatarsophalangeal (MTP) joint reaction forces were calculated for 11 normal females during the toe-off phase of gait while walking in bare feet and in high heeled shoes. A biomechanical model was used to calculate the forces utilizing kinematic, kinetic, footprint, and radiographic data. The results showed that the MTP joint reaction forces (FJ), the metatarsal-sesamoid forces (FS), and the resultant of these forces (FRES), were twice as large in high heels compared to barefoot walking. The average peak forces for barefoot and high-heeled gait were FJ: 0.8 and 1.58 times body weight, FS: 0.44 and 1.03 times body weight, and FRES: 0.93 and 1.88 times body weight. Also, the kinematics changed when wearing high heels, making angles of application of forces and sesamoidal articulations less favorable.

Work and power in gait of stroke patients.

Biomechanical analysis of the work and power patterns involved in gait provides insight into the nature of gait deficits and suggests methods for improvement. The purpose of this study was to describe the work and power characteristics during gait for both limbs of hemiplegic patients, and to determine the work and power variables related to self-selected speeds of walking. The gait of 30 ambulatory adults between the ages of 47 and 79 years was studied using two-dimensional cinematography and force-plate data in a link-segment model. About 40% of the positive work required for walking was performed by the muscles of the affected side. Major contributors were the ankle plantar flexors, hip flexors, and hip extensors. The results suggest interdependence between the limbs and between muscle groups of the same limb; a need for further research is indicated.

Work and power in hemiplegic cerebral palsy gait.

The purpose of this descriptive study was to quantify the work that is accomplished by major muscle groups of the affected limb of 10 children with spastic hemiplegia secondary to cerebral palsy during walking. Cinematographic film and force-plate data were used in a biomechanical link-segment model to calculate the positive and negative work performed by the muscles around each joint. The results revealed that the ankle plantar flexors produced just over a third of the positive work for the affected limb instead of the normal two thirds. The greatest proportion of positive work was performed by the hip muscles. More research using work and power analyses will assist in prescribing and determining the effectiveness of treatments.

Feedback of joint angle and EMG in gait of able-bodied subjects.

Recent developments in the ability to identify discrete disturbances in gait patterns have led to the development of a computer-assisted feedback system which can provide continuous visual and auditory feedback to a walking subject concerning some discrete aspect of his gait. The purpose of this study was to determine if able-bodied subjects could use this feedback to modify their gait according to externally imposed targets set for exaggerated joint motions or muscle activity, or for changes in the timing of these movements, or for both parameters together. Two groups of able-bodied older adults were presented with either knee and ankle joint angle feedback or quadriceps electromyographic feedback over four identical sessions. Records were kept of performance relative to the targets set for amplitude, timing, and for both parameters together. Results indicated that able-bodied subjects could modify the amplitude and timing of movements in the presence of feedback; they also suggested that the use of this approach in the reeducation of pathologic gait patients should be explored.

Joint reaction forces at the first MTP joint in a normal elderly population.

The calculation of net ankle, knee, and hip joint reaction forces is an often applied procedure in the analysis of gait. Except for very few studies, joint reaction forces have not been measured in other joints such as the fingers, wrist, elbow, shoulder and toes. In this study the joint reaction forces between the metatarsal head and the proximal phalanx and the metatarsal head and the sesamoids are calculated for the push off phase during gait. The results of ten normal elderly subjects show that the maximum resultant loads of the two articulations lie close to the longitudinal axis of the metatarsal. The knowledge of the magnitude and direction of the joint reaction forces of a normal elderly population will be essential for the design of an optimal fixation of an artificial anatomical first MTP joint.

Joint angle feedback and biomechanical gait analysis in stroke patients: a case report.

The purpose of this case report is to demonstrate the use of gait analysis and computer-assisted visual and auditory feedback (CAF) in the treatment of a patient with stroke secondary to hemiplegia. Two-dimensional kinematic and kinetic gait analyses were performed to determine the objectives of treatment and to evaluate the results. The CAF hardware and software permitted immediate visual feedback of performance relative to the desired target with auditory reinforcement if the target was reached in the desired phase of the gait cycle. The objective of the treatment was to increase knee flexion during push-off and pull-off. After four weekly treatments, the patient's gait velocity and stride length, in addition to transfers between kinetic energy and potential energy, were significantly improved. The patient demonstrated a downward trend in total mechanical energy costs and an upward trend in the amount of energy conservation, as well as increased knee flexion. These promising results indicate a need for further research into the use of CAF as a tool in motor learning for rehabilitation.

Mechanical energy patterns in gait of cerebral palsied children with hemiplegia.

The mechanical energy costs of walking were studied in 10 cerebral palsied children with hemiplegia to determine whether their values were substantially different from normal and, if so, to discover the movements that were responsible. A two-dimensional, sagittal-plane cinematographic analysis of the subjects' normal walking was undertaken. This technique provided continuous information about the mechanical energy costs of the whole body and each of its parts, the energy types involved, and the amounts of energy conserved. In most cases, the energy costs were above normal and were attributable to poor patterns of exchange between the potential and kinetic energy types of the head, arms, and trunk segment; to very low levels of kinetic energy that precluded exchange; or to both. We concluded that attention should be directed to restoring the sinusoidal pattern of motion and to the fluctuating speeds during each gait cycle when energy costs are a therapeutic consideration.

Mechanical energy of walking of stroke patients.

The mechanical energy costs of walking have been studied in ten stroke patients with hemiplegia. A two-dimensional sagittal plane cinematographic analysis of two strides of the subjects' normal walking was undertaken, yielding continuous information about the mechanical energy costs of the whole body and each of its parts, about the energy types involved, and the amounts of energy conservation. The large head, arms, and trunk (HAT) were found to dominate the total pattern. Three major disturbances were seen. In contrast to normal subjects who show energy-conserving negatively correlated potential and kinetic energy curves for the HAT, the subjects who demonstrated the first disturbance showed gross irregularity of the curves, with almost no opportunity for exchange between energy types. In a second disturbance the curves of the HAT showed some energy-conserving portions, but levels of kinetic energy curves were low, resulting in little energy exchange. In the third disturbance, some exchange was evident, but the pattern was dominated by potential energy changes in the form of a single large rise and fall, coinciding with swing phase of the affected leg. Each of these disturbances would require a different approach to treatment. Although mechanical energy analyses do not reflect certain energy costs, such as the effort required to hold the body up against the pull of gravity and that used in contracting antagonist muscles, they could be of considerable assistance in pinpointing costly variations in energy patterns during walking and in determining appropriate treatment procedures.

Predictions of knee and ankle moments of force in walking from EMG and kinematic data.

A deterministic model was developed and validated to calculate instantaneous ankle and knee moments during walking using processed EMG from representative muscles, instantaneous joint angle as a correlate of muscle length and angular velocity as a correlate of muscle velocity, and having available total instantaneous joint moments for derivation of certain model parameters. A linear regression of the moment on specifically processed EMG, recorded while each subject performed cycled isometric calibration contractions, yielded the constants for a basic moment-EMG relationship. Using the resultant moment for optimization, the predicted moment was proportionally augmented for longer muscle lengths and reduced for shorter lengths. Similarly, the predicted moment was reduced for shortening velocities and increased if the muscle was lengthening. The plots of moments predicted using the full model and those calculated from link segment mechanics followed each other quite closely. The range of root mean square errors were: 3.2-9.5 Nm for the ankle and 4.7-13.0 Nm for the knee.

The pedynograph: a clinical tool for force measurement and gait analysis in lower extremity amputees.

The pedynograph is a simple, inexpensive piece of equipment which can be used in the clinical setting to monitor amputee gait. Strain gauges applied to the pylon of a modular prosthesis and incorporated in an appropriate electrical circuit provide measurements of axial load which are displayed on an oscilloscope during ambulation. Preliminary experience with the described equipment has shown that it is of value in monitoring and regulating weight bearing in patients with healing or maturing stumps or impairment of stump sensation. Gait and prosthetic problems can be analyzed, their correction documented and a permanent record of amputee performance provided.