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Purpose. To assess the concurrent validity of the Human Activity Profile (HAP) with stroke and healthy control individuals, when reported by the subject or a proxy and compared to observed performance, used as gold standard; factors related to discrepancies; as well as to determine variables that could best predict physical activity levels. Methods. A total of 24 stroke and 23 healthy control subjects took part in the study. Functional outcome measures included personal/demographic factors, HAP, the 10-meter walk, and cognition. Results. Strong relationships were found between self-reported and observed scores for both groups (r = 0.89 - 0.99). The relationships between proxy and observed scores were acceptable for stroke (r = 0.80 - 0.87) but lower for control subjects (r = 0.65 - 0.75), with intraclass correlation coefficients (ICCs) ranging from 0.69 - 0.89. Significant differences were found between proxy and observed scores for stroke, but not for control subjects. Discrepancies between scores showed little predictability from selected variables. For stroke subjects, the strongest variable explaining physical activity levels was walking speed (r2 = 43%) and the best combination of variables was walking speed plus cognition (r2 = 55%). Conclusions. Self-reported HAP was an excellent measure both for stroke and control subjects and related well to observed performance. Proxy reports appear to be valid for stroke subjects. HAP was significantly related to measures of walking speed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

With increasing usage of many types of total elbow replacements, there is a continuing need for clinical series that report survivorship, complications and revisions, and performance of single types of implants over extended time periods. The purpose of this study was to assess the long-term effectiveness of all implants of the Sorbie-QUESTOR (SQ) unlinked surface arthroplasty conducted by a single surgeon (C.S.) over 15 years at a single site, and to determine whether there were diagnostic group differences. Between 1995 and 2002, 51 S-Q prosthetic elbows were implanted into 44 patients. The patient groups were hemophilia, rheumatoid arthritis, and "other," which included osteoarthritis, traumatic arthritis, psoriatic arthritis, and reactive arthritis. Annual evaluations included scores of pain, range of motion, and function. The most recent annual evaluation was included in the data set. Details of complications and revisions were recorded. The hemophiliac group had the best survival outcomes at 87.5%. Eighteen prostheses required revision or removal with all but 3 retained or replaced. Postoperatively, 73% rated their pain as 'slight' or 'none'. The hemophilia and rheumatoid arthritis groups made very large total flexion/extension gains. The rheumatoid arthritis group made significant forearm motion gains. Average functional assessment gains were nearly 2 grades of 5 functional levels and were significant for all groups. The S-Q surface arthroplasty has demonstrated long-term effectiveness in patients with a variety of elbow joint pathologies showing reduction in pain, large gains in joint range and function, and good long-term survival., (Copyright 2011, SLACK Incorporated.)

Background: Hip abductor muscle weakness may result in impaired frontal-plane pelvic control during gait, leading to greater medial compartment loading in people with knee osteoarthritis (OA)., Objective: This study investigated the effect of an 8-week home strengthening program for the hip abductor muscles on knee joint loading (measured by the external knee adduction moment during gait), strength (force-generating capacity), and function and pain in individuals with medial knee OA., Design: The study design was a nonequivalent, pretest-posttest, control group design., Setting: Testing was conducted in a motor performance laboratory., Patients: An a priori sample size calculation was performed. Forty participants with knee OA were matched for age and sex with a control group of participants without knee OA., Intervention: Participants with knee OA completed a home hip abductor strengthening program., Measurements: Three-dimensional gait analysis was performed to obtain peak knee adduction moments in the first 50% of the stance phase. Isokinetic concentric strength of the hip abductor muscles was measured using an isokinetic dynamometer. The Five-Times-Sit-to-Stand Test was used to evaluate functional performance. Knee pain was assessed with the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire., Results: Following the intervention, the OA group demonstrated significant improvement in hip abductor strength, but not in the knee adduction moment. Functional performance on the sit-to-stand test improved in the OA group compared with the control group. The OA group reported decreased knee pain after the intervention., Limitations: Gait strategies that may have affected the knee adduction moment, including lateral trunk lean, were not evaluated in this study., Conclusions: Hip abductor strengthening did not reduce knee joint loading but did improve function and reduce pain in a group with medial knee OA.

Background: Comparisons of treadmill and overground walking following stroke indicate that symmetry in temporal-distance measures is better on the treadmill suggestive of better gait economy. We examined this issue by examining the kinematic, kinetic and metabolic demands associated with overground and treadmill walking at matched speeds and also explored the effect of increasing treadmill speed., Methods: Ten people with hemiparesis walked overground at their preferred speed which was matched on the treadmill. Belt speed was then increased 10% and 20% above preferred speed. Temporal-distance outcomes, angular kinematics and vertical ground reaction forces were recorded during steady state (stable heart rate and oxygen uptake)., Findings: Step and stance times were longer when walking overground but the degree of symmetry was comparable for both surfaces. In contrast kinematic data revealed significant interlimb asymmetry with respect to all lower limb joint excursions during overground walking accompanied by higher vertical ground reaction forces at push-off. The metabolic demands, however, were lower when walking overground than on the treadmill. Increasing the belt speed increased angular displacements and the vertical forces associated with both limbs such that symmetry remained unchanged. Metabolic demands increased significantly., Interpretation: People with stroke adopt a more symmetrical kinematic walking pattern on the treadmill which is maintained at faster belt speeds. Surprisingly, at matched speed the metabolic cost was significantly higher with treadmill walking. We suggest further research to explore whether an increased reliance on the hip musculature to compensate lower push-off forces could explain the higher the energy cost.

Purpose: To characterize the effects of botulinum toxin A treatment of spastic plantar flexors in stroke on joint mobility and gait kinematics and kinetics., Method: Nine patients with hemiparetic stroke presenting with ankle hypertonicity participated in this exploratory open-label case series study. Comprehensive gait analysis provided bilateral kinematic and kinetic information for the ankle, knee, and hip joints throughout the stance phase. Data were obtained at baseline, 2 weeks, and 10 weeks post botulinum toxin injection of the spastic plantar flexors., Results: Passive ankle range of motion increased post injection (p < .05). The amount of plantarflexion in late stance was significantly reduced (p < .05) while the maximum dorsiflexion increased in midstance at 10 weeks post treatment. The angular displacement profiles for the knee revealed that patients tended to display less hyperextension following treatment (p = .053). No significant changes in kinetic measures were found; however, case-by-case observations suggested that most patients experienced improvements in positive work production., Conclusions: The findings indicate that botulinum toxin treatment results in improved joint mobility and ankle kinematics and, in some patients, increases in positive work, suggesting better gait performance.

Background: Although treadmill and overground walking appear to be biomechanically similar in healthy, young adults it is not known whether this can be generalized to older subjects or if the metabolic demands are correspondingly comparable., Methods: Ten healthy adults between 50 and 73 years of age walked at the same speed overground and on a treadmill. Temporal parameters, angular kinematics and vertical ground reaction forces were recorded during walking once subjects were in steady state as determined from their heart rate and oxygen uptake., Findings: Step, stride and joint angular kinematics were similar for both modes of walking with the exception of the maximum hip flexion and knee extension which were more pronounced with treadmill or overground walking, respectively but in both instances differed by less than 3 degrees. Vertical ground reaction force profiles were similar although the peak associated with push-off was 5.5% smaller with treadmill walking. The metabolic requirements of treadmill walking were about 23% higher than that associated with overground walking., Interpretation: While treadmill and overground walking are biomechanically similar, the metabolic cost of treadmill walking is higher. Clinically this may be important when using a treadmill for gait retraining in patient populations as it may lead to premature fatigue or undesirable physiologic challenge.

Background: Pain experienced by people with knee osteoarthritis is related to psychosocial factors and damage to articular tissues and/or the pain pathway itself. Mechanical factors have been speculated to trigger this pain experience; yet mechanics have not been identified as a source of pain in this population. The purpose of this study was to identify whether mechanics could explain variance in pain intensity in people with knee osteoarthritis., Methods: Data from 53 participants with physician-diagnosed knee osteoarthritis (mean age=68.5 years; standard deviation=8.6 years) were analyzed. Pain intensity was reported on the Western Ontario and McMaster Universities Osteoarthritis Index. Mechanical measures included weight-bearing varus-valgus alignment, body mass index and isokinetic quadriceps torque. Gait analysis captured the range of adduction-abduction angle, range of flexion-extension angle and external knee adduction moment during level walking., Findings: Pain intensity was significantly related to the dynamic range of flexion-extension during gait and body mass index. A total of 29% of the variance in pain intensity was explained by mechanical variables. The range of flexion-extension explained 18% of variance in pain intensity. Body mass index added 11% to the model. The knee adduction moment was unrelated to pain intensity., Interpretation: The findings support that mechanical factors are related to knee osteoarthritis pain. Because limitations in flexion-extension range of motion and body size are modifiable factors, future research could examine whether interventions targeting these mechanics would facilitate pain management.

Background: Self-efficacy is a determinant of walking performance in older adults with knee osteoarthritis. We examined whether self-efficacy mediated the effect of age, psychosocial, impairment, and mechanical factors on walking performance., Methods: Fifty-four participants with knee osteoarthritis completed the Six Minute Walk test and Arthritis Self-Efficacy Scale. Independent variables reflected age, psychosocial (depressive symptoms), impairment (pain, stiffness), and mechanical (strength, obesity) factors., Results: Self-efficacy fully mediated the effect of age and impairments on walking. The effects of strength were only partially mediated by self-efficacy. Depressive symptoms and obesity were not mediated by self-efficacy., Conclusions: These findings are consistent with Social Cognitive Theory, according to which age may alter outcome expectations, and impairments like pain and stiffness provide negative physiological feedback to influence performance. Mechanical factors like strength and obesity may better represent a person's capabilities and interact with other variables to influence physical performance in older adults with knee osteoarthritis.

Background: Knowledge of associations between changes in muscle work with changes in gait speed could assist gait training in persons with stroke. The purpose of the study was to determine changes in the work of major muscle groups during gait that were associated with increases in walking speed of persons with stroke following training., Methods: The gait of 28 subjects (14 males, 14 females) with mean age of 64.2 (SD 11.7) years, at 4.8 (SD 6.9) years post stroke was studied using two-dimensional motion analysis before and after a strength training program. Outcome variables were changes in gait speed and changes in work associated with the hip flexors and extensors, knee flexors and extensors and ankle plantar flexors bilaterally. A stepwise linear regression analysis determined best positive work predictors of changes in gait speed., Findings: Hip extension work in early stance and ankle plantarflexion work in late stance of the affected side accounted for 74.9% of the variance in change of gait speed; a second model showed that hip extension work in early stance of the affected and less-affected sides accounted for 74.3%, a similar amount of variance., Interpretation: This work is the first to explore the changes in muscle work during gait that are associated with speed increases in persons with stroke. Augmenting hip extensor work in early stance on both sides, as well as ankle plantarflexion thrust on the affected side may be particularly beneficial in increasing the speed of walking of persons with stroke.

Background: Although gait characteristics have been well documented in people with knee osteoarthritis, little is known about the relationships between gait characteristics and performance or disability. Our purpose was to examine the role of knee kinematics and kinetics on walking performance and disability in people with knee osteoarthritis. We also examined whether pain mediated the relationship between the knee adduction moment and performance or disability., Methods: Three-dimensional gait analysis was conducted on 54 people with medial compartment knee osteoarthritis. Performance was quantified with the Six Minute Walk test and disability was self-reported on the Short Form-36. The pain subscale of the Western Ontario McMaster Universities Osteoarthritis Index and the functional self-efficacy subscale of the Arthritis Self-Efficacy scale were completed., Findings: A step-wise linear regression demonstrated that the variance in Six Minute Walk test scores was explained by functional self-efficacy (50%) and the range of knee motion (8%). The variance in Short Form-36 was explained by pain (36%), the peak extension angle (19%) and the range of knee motion (4%). Pain was unrelated to the knee adduction moment so analyses of pain as a mediator of the adduction moment on either performance or disability were halted., Interpretation: Kinematic output from the motor control system is useful in understanding some variance in current performance and disability in people with knee osteoarthritis. The knee adduction moment was unrelated to these variables and pain did not mediate between the knee adduction moment and performance or disability. Therefore this moment does not explain current clinical status in people with knee osteoarthritis based on the measures of performance and disability used in this study.

Objective: To determine the accuracy (criterion-related validity) of real-time clinical observations of push-off in gait after stroke., Design: Criterion-related validity study of gait observations., Setting: Rehabilitation hospital in Australia., Participants: Eleven participants with stroke and 8 treating physical therapists., Interventions: Not applicable., Main Outcome Measures: Pearson product-moment correlation between physical therapists' observations of push-off during gait and criterion measures of peak ankle power generation from a 3-dimensional motion analysis system., Results: A high correlation was obtained between the observational ratings and the measurements of peak ankle power generation (Pearson r =.98). The standard error of estimation of ankle power generation was .32W/kg., Conclusions: Physical therapists can make accurate real-time clinical observations of push-off during gait following stroke.

Objective: Self efficacy, the confidence an individual has to perform a task, is an important determinant of physical performance in individuals with knee osteoarthritis (OA). The purpose of this study was to determine what personal, pathophysiologic, and impairment factors relate to self efficacy for physical tasks in community-dwelling adults with knee OA., Methods: Fifty-four persons with radiographically confirmed knee OA (mean +/- SD age 68.3 +/- 8.7 years, range 50-87 years) participated. The Functional Self-Efficacy subscale of the Arthritis Self-Efficacy Scale was the dependent measure. Independent measures included age, education, scores from the Center for Epidemiologic Studies Depression and State-Trait Anxiety Inventory questionnaires, medial joint space and varus/valgus tibiofemoral angle from radiographs, body mass index, and isokinetic quadriceps and hamstrings strength. Knee pain and stiffness, assessed using the Western Ontario and McMaster Universities Osteoarthritis Index, were independent measures., Results: Fifty-one percent of the variance of Functional Self Efficacy was explained by knee stiffness, hamstrings strength, age, and depression scores. Pain, education, anxiety, radiographic joint space, and body weight did not significantly contribute to the variance in Functional Self-Efficacy scores. Substituting quadriceps strength for hamstrings strength resulted in a regression model that included only stiffness, age, and depression, which explained nearly as much variance as the original model., Conclusion: Self efficacy for physical tasks is related to the sensation of stiffness, hamstrings strength, age, and level of depressive symptoms in persons with knee OA. Clinicians and researchers could consider these variables when assessing the level of self efficacy for physical tasks in persons with knee OA.

Objectives: To identify the determinants of self-report mobility measures in people with knee osteoarthritis (OA) and to compare self-report measures with physical performance., Design: Cross-sectional, prospective., Setting: Motor performance laboratory and human mobility research center., Participants: A convenient sample of 54 participants with medial compartment knee OA (32 women, 22 men; age 68.3+/-8.7y; range, 50-87y). Three participants were excluded because of the presence of lateral knee OA on radiographs., Interventions: Not applicable., Main Outcome Measures: Self-reports were recorded by using the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Performance measures included the six-minute walk test (6MWT), Timed Up & Go (TUG) test, and a standardized stair-climbing task (STR)., Results: Stepwise linear regression analysis identified models that included pain, quadriceps and hamstrings strength, and depression to explain 62% to 73% of the variance in scores on the physical functioning subscale of the WOMAC and the SF-36. These self-report measures had a moderate relation (r range, .46-.64) with performance measures (6MWT, TUG, STR)., Conclusions: Self-report measures were strongly related to pain; physical performance measures were strongly related to self-efficacy. Regression models showed that self-report scores reflect pain, knee strength, and depression. The relation between self-report and performance measures was moderate, suggesting that these examine different aspects of mobility.

Background and Purpose: This cross-sectional study evaluated the relative contributions of psychosocial and mechanical variables to physical performance measures in people with knee osteoarthritis (OA)., Subjects: Fifty-four subjects (age, in years: mean=68.3, SD=8.7, range=50-87) with radiographically confirmed knee OA were included in this study., Methods: Physical performance measures included the Six-Minute Walk Test (SMW), the Timed "Up & Go" Test (TUG), and a stair-climbing task (STR). Responses to psychosocial questionnaires that reflect depression, anxiety, and self-efficacy (a person's confidence in his or her ability to complete a task) were collected. Mechanical variables measured included body mass index and knee strength (force-generating capacity of muscle). Stepwise linear regressions were performed with the SMW, TUG, and STR as separate dependent variables., Results: Functional self-efficacy explained the greatest amount of variance in all performance measures, contributing 45% or more. Knee strength and body weight also explained some variance in performance measures. Anxiety and depression did not explain any variance in performance., Discussion and Conclusion: Physical therapists evaluating the significance of the SMW, TUG, and STR scores in subjects with knee OA should note that a large part of each score reflects self-efficacy, or confidence, for physical tasks, with some contributions from knee strength and body weight.

Background and Purpose: Physical therapists routinely observe gait in clinical practice. The purpose of this study was to determine the accuracy and reliability of observational assessments of push-off in gait after stroke., Subjects: Eighteen physical therapists and 11 subjects with hemiplegia following a stroke participated in the study., Methods: Measurements of ankle power generation were obtained from subjects following stroke using a gait analysis system. Concurrent videotaped gait performances were observed by the physical therapists on 2 occasions. Ankle power generation at push-off was scored as either normal or abnormal using two 11-point rating scales. These observational ratings were correlated with the measurements of peak ankle power generation., Results: A high correlation was obtained between the observational ratings and the measurements of ankle power generation (mean Pearson r=.84). Interobserver reliability was moderately high (mean intraclass correlation coefficient [ICC (2,1)]=.76). Intraobserver reliability also was high, with a mean ICC (2,1) of.89 obtained., Discussion and Conclusion: Physical therapists were able to make accurate and reliable judgments of push-off in videotaped gait of subjects following stroke using observational assessment. Further research is indicated to explore the accuracy and reliability of data obtained with observational gait analysis as it occurs in clinical practice.

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 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.

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.

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.

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., (Copyright © 1994. Published by Elsevier Ltd.)

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.