Single Support Duration Research Articles

The effect of low-level laser therapy and physical exercise on pain, stiffness, function, and spatiotemporal gait variables in subjects with bilateral knee osteoarthritis: a blind randomized clinical trial

Objective: To evaluate the effects of individual and combination therapies (low-level laser therapy and physical exercises) on pain, stiffness, function, and spatiotemporal gait variables in subjects with bilateral knee osteoarthritis (OA).Methods: Subjects with knee OA (Grades 1–3) were evaluated and randomized into four groups: Control Group (CG), untreated; Laser Group (LG), treated with laser at 808 nm, 5.6 J; Exercise Group (EG), treated with exercise; and Laser + Exercise Group (LEG), treated with laser and exercises. The treatment was carried out twice a week for 2 months. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire was applied for evaluation and reevaluation; evaluation of spatiotemporal gait variables was performed using GAITRite equipment.Results: The EG showed significant improvement in pain (p = 0.006) and function (p = 0.01) according to WOMAC. Regarding gait variables, in intergroup analysis after 8 weeks all groups receiving intervention showed a significant increase in gait speed: LG versus CG (p = 0.03); EG versus CG (p = 0.04) and LEG versus CG (p = 0.005). Only the group treated with laser + exercise showed a significant increase (p = 0.009) in the cadence and duration of single right limb support (p = 0.04), and only the groups treated with exercise and laser + exercise showed significant decreases in the duration of right limb support (p = 0.035 and p = 0.003, respectively), compared to the CG.Conclusions: The group treated only with exercise showed improvement in WOMAC questionnaire scores. Regarding the gait variables, all groups undergoing the interventions showed increases in the gait speed compared to the CG. The laser and exercise combination therapy provided the best results for the other gait variables (cadence and duration of right limb support and duration of single right limb support).Implications for rehabilitationThere are differences in gait patterns in patients with knee OA, including decreased gait speed, cadence, and step length.The results shown in the present study provide additional information about the physical therapy approaches that should be chosen during clinical practical to improve gait performance in individuals with knee osteoarthritis.The improvement in gait performance is a relevant issue due to the fact that is associated to physical independence and better quality of life.

Abnormal gait pattern emerges during curved trajectories in high-functioning Parkinsonian patients walking in line at normal speed.

BackgroundSeveral patients with Parkinson´s disease (PD) can walk normally along straight trajectories, and impairment in their stride length and cadence may not be easily discernible. Do obvious abnormalities occur in these high-functioning patients when more challenging trajectories are travelled, such as circular paths, which normally implicate a graded modulation in the duration of the interlimb gait cycle phases?MethodsWe compared a cohort of well-treated mildly to moderately affected PD patients to a group of age-matched healthy subjects (HS), by deliberately including HS spontaneously walking at the same speed of the patients with PD. All participants performed, in random order: linear and circular walking (clockwise and counter-clockwise) at self-selected speed. By means of pressure-sensitive insoles, we recorded walking speed, cadence, duration of single support, double support, swing phase, and stride time. Stride length-cadence relationships were built for linear and curved walking. Stride-to-stride variability of temporal gait parameters was also estimated.ResultsWalking speed, cadence or stride length were not different between PD and HS during linear walking. Speed, cadence and stride length diminished during curved walking in both groups, stride length more in PD than HS. In PD compared to HS, the stride length-cadence relationship was altered during curved walking. Duration of the double-support phase was also increased during curved walking, as was variability of the single support, swing phase and double support phase.ConclusionThe spatio-temporal gait pattern and variability are significantly modified in well-treated, high-functioning patients with PD walking along circular trajectories, even when they exhibit no changes in speed in straight-line walking. The increased variability of the gait phases during curved walking is an identifying characteristic of PD. We discuss our findings in term of interplay between control of balance and of locomotor progression: the former is challenged by curved trajectories even in high-functioning patients, while the latter may not be critically affected.

A randomized controlled trial on providing ankle-foot orthoses in patients with (sub-)acute stroke: Short-term kinematic and spatiotemporal effects and effects of timing

Initial walking function is often limited after stroke, and regaining walking ability is an important goal in rehabilitation. Various compensatory movement strategies to ensure sufficient foot-clearance are reported. Ankle-foot orthoses (AFOs) are often prescribed to improve foot-clearance and may influence these strategies. However, research studying effects of actual AFO-provision early after stroke is limited. We conducted an explorative randomized controlled trial and aimed to study the short-term effects of AFO-provision on kinematic and spatiotemporal parameters in patients early after stroke. In addition, we studied whether timing of AFO-provision influenced these effects. Unilateral hemiparetic patients maximal six weeks post-stroke were randomly assigned to AFO-provision: early (at inclusion) or delayed (eight weeks later). Three-dimensional gait-analysis with and without AFO in randomized order was performed within two weeks after AFO-provision. Twenty subjects (8 early, 12 delayed) were analyzed. We found significant positive effects of AFO-provision for ankle dorsiflexion at initial contact, foot-off and during swing (−3.6° (7.3) vs 3.0° (3.9); 0.0° (7.4) vs 5.2° (3.7); and −6.1° (7.8) vs 2.6° (3.5), respectively), all p<0.001. No changes in knee, hip and pelvis angles were found after AFO-provision, except for knee (+2.3°) and hip flexion (+1.6°) at initial contact, p≤0.001. Significant effects of AFO-provision were found for cadence (+2.1 steps/min, p=0.026), stride duration (−0.08s, p=0.015) and single support duration (+1.0%, p=0.002). Early or delayed AFO-provision after stroke did not affect results. In conclusion, positive short-term effects of AFO-provision were found on ankle kinematics early after stroke. Timing of AFO-provision did not influence the results.Trial registration number: NTR1930

Gait parameter control timing with dynamic manual contact or visual cues.

We investigated the timing of gait parameter changes (stride length, peak toe velocity, and double-, single-support, and complete step duration) to control gait speed. Eleven healthy participants adjusted their gait speed on a treadmill to maintain a constant distance between them and a fore-aft oscillating cue (a place on a conveyor belt surface). The experimental design balanced conditions of cue modality (vision: eyes-open; manual contact: eyes-closed while touching the cue); treadmill speed (0.2, 0.4, 0.85, and 1.3 m/s); and cue motion (none, ±10 cm at 0.09, 0.11, and 0.18 Hz). Correlation analyses revealed a number of temporal relationships between gait parameters and cue speed. The results suggest that neural control ranged from feedforward to feedback. Specifically, step length preceded cue velocity during double-support duration suggesting anticipatory control. Peak toe velocity nearly coincided with its most-correlated cue velocity during single-support duration. The toe-off concluding step and double-support durations followed their most-correlated cue velocity, suggesting feedback control. Cue-tracking accuracy and cue velocity correlations with timing parameters were higher with the manual contact cue than visual cue. The cue/gait timing relationships generalized across cue modalities, albeit with greater delays of step-cycle events relative to manual contact cue velocity. We conclude that individual kinematic parameters of gait are controlled to achieve a desired velocity at different specific times during the gait cycle. The overall timing pattern of instantaneous cue velocities associated with different gait parameters is conserved across cues that afford different performance accuracies. This timing pattern may be temporally shifted to optimize control. Different cue/gait parameter latencies in our nonadaptation paradigm provide general-case evidence of the independent control of gait parameters previously demonstrated in gait adaptation paradigms.

Obstacle Crossing During Gait in Children With Cerebral Palsy: Cross-Sectional Study With Kinematic Analysis of Dynamic Balance and Trunk Control.

Balance problems are common in children who have cerebral palsy (CP) but are active and ambulant. Control of the whole-body center of mass is critical in maintaining dynamic stability during challenging mobility tasks, such as clearing an obstacle while walking. The objective of this study was to compare trunk and lower limb kinematics and center-of-mass control in children with CP and those in children with typical development during obstacle crossing. This was a cross-sectional study. Thirty-four children who were 5 to 17 years of age (17 with CP and 17 with typical development) and matched in age and height completed 2 gait trials involving crossing a 10-cm obstacle. Three-dimensional kinematic and kinetic data were captured with a general-purpose 3-dimensional motion tracking system and forceplates. Trunk data were captured with a validated model. All children cleared the obstacle with similar hip and knee kinematics, step length, and single-support duration. In children with CP, step width was increased by 4.81 cm, and center-of-mass velocity was significantly slower at lead limb toe-off (0.31 m/s) and during lead limb clearance (0.2 m/s). Children with CP showed altered trunk and pelvis movement, characterized by significantly greater pelvic obliquity, pelvic tilt, and trunk rotation throughout the task, increased lateral trunk lean during lead limb crossing (3.7°), and greater sagittal trunk movement as the trail limb crossed (5.1°). The study was not powered to analyze differences between children with diplegia and those with hemiplegia. Children with CP required greater adjustments at the trunk and pelvis to achieve successful obstacle crossing. The increase in trunk movement could have been compensatory for reduced stability distally or for a primary problem reflecting poor proximal control. The findings suggest that rehabilitation should focus on both proximal trunk control and distal stability to improve balance.

Computational evaluation of load carriage effects on gait balance stability

Evaluating the effects of load carriage on gait balance stability is important in various applications. However, their quantification has not been rigorously addressed in the current literature, partially due to the lack of relevant computational indices. The novel Dynamic Gait Measure (DGM) characterizes gait balance stability by quantifying the relative effects of inertia in terms of zero-moment point, ground projection of center of mass, and time-varying foot support region. In this study, the DGM is formulated in terms of the gait parameters that explicitly reflect the gait strategy of a given walking pattern and is used for computational evaluation of the distinct balance stability of loaded walking. The observed gait adaptations caused by load carriage (decreased single support duration, inertia effects, and step length) result in decreased DGM values (p < 0.0001), which indicate that loaded walking motions are more statically stable compared with the unloaded normal walking. Comparison of the DGM with other common gait stability indices (the maximum Floquet multiplier and the margin of stability) validates the unique characterization capability of the DGM, which is consistently informative of the presence of the added load.

Afferent control of walking: Are there distinct deficits associated to loss of fibres of different diameter?

ObjectivesTo compare the gait pattern in patients affected by different types of neuropathy. MethodsWe recruited healthy subjects (HS, n=38), patients with Charcot–Marie–Tooth disease type 1A (CMT1A) (n=10) and patients with diabetic neuropathy (DNP) (n=12). Neuropathy impairment score and neuropathy score were assessed. Body sway during quiet stance, and spatio-temporal gait parameters were recorded. ResultsMost patients had reduced or absent tendon-tap reflexes. Strength of foot dorsiflexor muscles (p<0.05) and conduction velocity (CV) of leg nerves (p<0.0001) were more impaired in CMT1A than DNP, whereas joint-position sense was more affected (p<0.05) in DNP. Body sway while standing was larger in DNP compared to CMT1A and HS (p<0.01 and p<0.0001 respectively). During gait, the distribution of foot sole contact pressure was abnormal in CMT1A (p<0.05) but not in DNP. Velocity and step length were decreased, and foot yaw angle at foot flat increased, in DNP with respect to CMT1A and HS (both variables, p<0.001). Gait velocity and step length were decreased (p<0.005) also in CMT1A, but to a smaller extent than in DNP, so that the difference between patient groups was significant (p<0.0005). Duration of the double support was protracted in DNP compared to CMT1A and HS (p<0.0005). For DNP only, velocity of gait and duration of single support were correlated (p<0.05) both to sway path and lower limb muscle strength. ConclusionsChanges in both body sway and stance phase of gait were larger in DNP than CMT1A, indicating more impaired static and dynamic control of balance when neuropathy affects the small in addition to the large afferent fibres. Diminished somatosensory input from the smaller fibres rather than muscle weakness or foot deformity plays a critical role in the modulation of the support phase of gait. SignificanceThe analysis of balance and gait in patients with neuropathy can offer a tool for understanding the nature and functional impact of the neuropathy and should be included in their functional evaluation.

Over-ground walking on level and sloped surfaces in people with stroke compared to healthy matched adults

Purpose: To investigate the basic spatio-temporal gait characteristics of people with stroke whilst walking on sloped and level terrain, and to compare this performance to healthy matched adults. Method: Fifteen community dwelling people with stroke who walked with a hemiplegic gait and a reference group of 15 adults without impairments matched for sex, age and height participated in this descriptive, observational study. Basic gait spatio-temporal measures were recorded at self-selected speed across a GAITRite mat placed on level, uphill and downhill (ramp gradient 1:14 or 4.1°) surfaces. Measures recorded were gait speed, cadence, step length, support base, single and double limb support duration and step length symmetry. Group and walking condition effects were assessed by two separate 2-way (group × slope) repeated measures multivariate analysis of variance. Results: The stroke group walked slower (p < 0.001) than the reference group for all conditions. Within-group analyses found the stroke group decreased their speed and step length when walking downhill compared to level and uphill walking (p < 0.001). In contrast, the reference group maintained speed across all walking conditions. Conclusions: The findings suggest that walking on slopes affects gait speed in people with stroke and this may have implications when walking in the community.Implications for RehabilitationAlthough a high percentage of people achieve walking independence following a stroke, few achieve independent community mobility.Walking on slopes is an important aspect of community mobility.When walking down a standard gradient ramp, people with stroke reduced their speed and step length, relative to level over-ground and uphill walking.It is recommended that attention be directed to assessment and treatment of walking on slopes as part of stroke rehabilitation, as this may have implications when walking in the community.

Estimation of spatial-temporal gait parameters in level walking based on a single accelerometer: Validation on normal subjects by standard gait analysis

This paper investigates the ability of a single wireless inertial sensing device stuck on the lower trunk to provide spatial-temporal parameters during level walking. The 3-axial acceleration signals were filtered and the timing of the main gait events identified. Twenty-two healthy subjects were analyzed with this system for validation, and the estimated parameters were compared with those obtained with state-of-the-art gait analysis, i.e. stereophotogrammetry and dynamometry. For each side, from four to six gait cycles were measured with the device, of which two were validated by gait analysis. The new acquisition system is easy to use and does not interfere with regular walking. No statistically significant differences were found between the acceleration-based measurements and the corresponding ones from gait analysis for most of the spatial-temporal parameters, i.e. stride length, stride duration, cadence and speed, etc.; significant differences were found for the gait cycle phases, i.e. single and double support duration, etc. The system therefore shows promise also for a future routine clinical use.

Postural Instability and Gait Impairment During Obstacle Crossing in Parkinson's Disease

Stegemöller EL, Buckley TA, Pitsikoulis C, Barthelemy E, Roemmich R, Hass CJ. Postural instability and gait impairment during obstacle crossing in Parkinson's disease. ObjectiveTo examine whether Parkinson's disease (PD) affects gait behavior and stability while walking over an obstacle. DesignParallel group comparisons were completed in which participants completed 5 trials of normal walking and 5 trials of obstacle crossing while gait kinematics and kinetics were collected. SettingUniversity biomechanics laboratory. ParticipantsIndividuals with PD (n=10) and age- and sex-matched healthy older adults (n=10). InterventionsNot applicable. Main Outcome MeasuresGait parameters, obstacle clearance parameters, and center of mass motion were calculated during normal walking and obstacle crossing. ResultsResults revealed that decrements in gait performance in individuals with PD were amplified during obstacle crossing, suggesting that due to disease-related degradation, individuals with PD chose a more conservative strategy for obstacle crossing. Moreover, an increased duration of single limb support (18% increase), a decrease in anteroposterior range of motion (20% decrease), and an increase in mediolateral range of motion (36% increase, though not significant) coupled with the reduction in the distance between the center of pressure and center of mass (mean of 21% decrease across toe-off and heel strike) and increase in margin of stability (31% increase at toe-off and 71% increase at heel strike) may suggest that deficits in muscle strength and balance may contribute to this impairment. ConclusionsPersons with PD alter their behavior to reduce the mechanical demands and increase dynamic stability during obstacle avoidance tasks.

Are Spatiotemporal Gait Characteristics Reliable Outcome Measures in Children With Developmental Coordination Disorder?

To evaluate the reliability of spatiotemporal gait parameters used in the clinical evaluation of children with developmental coordination disorder (DCD). Participants recruited were asked to ambulate across a 4.5-meter GAITRite walkway (CIR Systems, Inc, Havertown, Pennsylvania) at a self-selected walking speed. The spatiotemporal parameters recorded for both limbs were: velocity (cm/sec), stance phase duration (%), swing phase duration (%), stride length (cm), double support duration (%), and single support duration (%). Intraclass correlation coefficient values attained in this study ranged from 0.24 to 0.73, with good reliability achieved for one parameter (cadence = 0.73), and moderate reliability for step length (0.55-0.58), stride length (0.57-0.61), and double support duration (0.56-0.59). The findings from this study indicate that the clinical evaluation of spatiotemporal gait parameters in children with DCD can yield reliable data for some parameters but further work on this is warranted.

Basic gait and symmetry measures for primary school-aged children and young adults. II: Walking at slow, free and fast speed

This study recorded basic gait data from 656 healthy primary school-aged children (5–13 years) and 81 young adults (18–27 years) whilst walking over-ground across a level walkway at varying speed. It investigated the effect of gait speed and re-examined the issue of gait maturation. Participants completed 6–8 walks at self-selected slow, free and fast speed along a GAITRite walkway whilst wearing athletic shoes. Outcome measures (non-normalized and normalized) were gait speed, cadence, step and stride length, step and stride time, support base, single and double support (%), stance duration (%), foot angle and associated symmetry measures. Compared to free speed, participants walked 24% slower for the slow speed and 30% faster for the fast speed (p<0.0001). Both normalized and non-normalized measures of cadence, step and stride length increased with speed (p<0.001) whereas step and stride time reduced (p<0.001). As a percentage of the gait cycle, single support and stance duration increased with speed (p<0.001) whereas double support reduced (p<0.001). Foot angle was significantly less (less toe-out) for the fast speed than the free and slow speeds (p<0.001) whereas support base was unaffected by speed. Symmetry measures were unaffected by age or speed. Step and stride symmetry differentials (combining conditions) fell around 0.8cm, whereas symmetry differentials for step and stance time, single and double support fell around 0.7%. This information can be used by clinicians and researchers to assess the gait of children.

Assessment of Gait Symmetry in Transfemoral Amputees Using C-Leg Compared With 3R60 Prosthetic Knees

In Brief The objective of the study was to investigate gait symmetry in transfemoral amputees using a hydraulic- and a microprocessor-controlled knee prosthesis. An A-B design with repeated measurements was chosen, and the measurements were carried out at a prosthetics/orthotics rehabilitation center. Nine unilateral transfemoral C-Leg bearing amputees participated in the study, of whom five subjects completed the study. Three-dimensional inverse dynamic gait analysis was performed on each subject. Each subject was then fitted with a 3R60 prosthesis. After a 1-week acclimation period, gait analysis was performed on the 3R60 prosthesis. The outcome measures were temporospatial symmetry, duration of single support on the sound side and the prosthetic side, and the introduced butterfly symmetry ratio. Spatial symmetry was not significantly different between the two prosthetic knees. Temporal symmetry was not significantly improved when subjects used the C-Leg. Single support was significantly longer on the sound side than on the prosthetic side (p < 0.05). However, no significant difference was observed between the two prosthetic knees. The butterfly symmetry ratio was not significantly improved when subjects used C-Leg. The butterfly patterns differed remarkably across subjects, which indicates different gait strategies, but the gait patterns within subjects were not influenced by the type of prosthetic knee. In conclusion, none of the outcome measures investigated showed a significantly improved gait symmetry when subjects used C-Leg compared with the mechanical prosthetic knee 3R60. This study investigated gait symmetry in transfemoral amputees using the microprocessor-controlled C-Leg and the 3R60 hydraulic knee prosthesis. The introduced symmetry parameter—the butterfly symmetry ratio—did not show significantly improved gait symmetry when subjects used the C-Leg compared with the 3R60 knee. This conclusion was supported by findings from three other outcome measures. However, it is suggested that the butterfly plot could be a promising clinical tool in the future to achieve better gait symmetry in transfemoral amputees.

Three-dimensional motion analysis of the effects of auditory cueing on gait pattern in patients with Parkinson’s disease: a preliminary investigation

Auditory cueing enhances gait in parkinsonian patients. Our aim was to evaluate its effects on spatiotemporal (stride length, stride time, cadence, gait speed, single and double support duration) kinematic (range of amplitude of the hip, knee and ankle joint angles registered in the sagittal plane) and kinetic (maximal values of the hip and ankle joint power) gait parameters using three-dimensional motion analysis. Eight parkinsonian patients performed 12 walking tests: 3 repetitions of 4 conditions (normal walking, 90, 100, and 110% of the mean cadence at preferred pace cued walking). Subjects were asked to uniform their cadence to the cueing rhythm. In the presence of auditory cues stride length, cadence, gait speed and ratio single/double support duration increased. Range of motion of the ankle joint decreased and the maximal values within the pull-off phase of the hip joint power increased. Thus, auditory cues could improve gait modifying motor strategy in parkinsonian patients.

Stabilometry is a predictor of gait performance in chronic hemiparetic stroke patients

In patients with spastic hemiparesis, centre of foot pressure (CoP) is shifted toward the unaffected limb during quiet stance. We hypothesised that abnormal gait features would correlate with the degree of asymmetry during stance. In 15 patients and 17 normals we recorded CoP and body sway by a force platform and measured spatial–temporal variables of gait with pedobarography. In patients CoP was shifted toward the unaffected limb and sway was larger than in normals. CoP position was associated with the decrease in strength of the affected lower-limb muscles. Spatio-temporal variables of gait were also affected by the disease. Cadence and velocity were decreased, duration of single support on the unaffected limb and of double support were increased with respect to normals. The degree of impairment of gait variables correlated with CoP. We found a negative relationship between velocity or cadence and CoP, and a positive relationship between duration of single support and CoP in the unaffected but not in the affected limb. Duration of double support correlated positively with CoP. CoP asymmetry during both standing and walking suggests that postural and gait problems share some common neural origin in hemiparetic patients. This asymmetry affects gait performance by increasing the time and effort needed to shift body weight toward the affected limb. The degree of postural asymmetry measured by stabilometry is associated with the level of impairment of gait variables.

Gait synchronized force modulation during the stance period of one limb achieved by an active partial body weight support system

Our purpose was to demonstrate the ability of an actively controlled partial body weight support (PBWS) system to provide gait synchronized support during the stance period of a single lower extremity while examining the affect of such a support condition on gait asymmetry. Using an instrumented treadmill and a motion capture system, we compared gait parameters of twelve healthy elderly subjects (age 65–80 years) during unsupported walking to those while walking with 20% body weight support provided during only the stance period of the right limb. Specifically, we examined peak three-dimensional ground reaction force (GRF) data and the symmetry of lower extremity sagittal plane joint angles and of time and distance parameters. A reduction in all three GRF components was observed for the supported limb during modulated support. Reductions observed in the vertical GRF were comparable to the desired 20% support level. Additionally, GRF components examined for the unsupported limb during modulated support were consistently similar to those measured during unsupported walking. Modulated support caused statistically significant increases in asymmetry for knee flexion during stance (increased 5.9%), hip flexion during late swing (increased 9.1%), and the duration of single limb support (increased 2.8%). However, the observed increases were similar or considerably less than the natural variability in the asymmetry of these parameters during unsupported walking. The ability of the active PBWS device to provide unilateral support may offer new and possibly improved applications of PBWS rehabilitation for patients with unilateral walking deficits such as hemiparesis or orthopaedic injury.

Locomotor Strategies in Obese and Non‐obese Children

The constant strain in obese children may increase the risks of articular problems in adulthood. In the short term, obesity in children could lead to modifications of the gait pattern. The purpose of this study was to compare biomechanical parameters between obese and non-obese children during self-paced walking. Gait analysis was performed on 10 non-obese and 10 obese (body weight > 95th percentile) children between 8 and 13 years of age. Subjects were asked to walk at their own pace on a 10-m walkway with two embedded AMTI force plates (Advanced Mechanical Technology, Watertown, MA) sampling at 960 Hz. Kinematics were captured with eight VICON optoelectronic cameras (Oxford Metrics Limited, Oxford, United Kingdom) recording at 60 Hz. Obese children modified their hip motor pattern by shifting from extensor to flexor moment earlier in the gait cycle. This led obese children to significantly decrease the mechanical work done by the hip extensors during weight acceptance and significantly increase the mechanical work done by the hip flexors compared with non-obese children. The ratio of power-absorption-by-hip-flexors to power-generation-by-hip-flexors was also significantly increased in the obese group compared with non-obese children. Finally, there was a significant decrease in the single support duration in the obese group compared with non-obese. The kinetics analyzed showed that obese children could take advantage of a passive hip strategy to achieve forward progression during walking. However, considering that they are mechanically less efficient to transfer energy, walking at a natural cadence should be an appropriate exercise to reduce weight in obese children.

Basic walker-assisted gait characteristics derived from forces and moments exerted on the walker's handles: Results on normal subjects

This paper describes a method that passively assesses basic walker-assisted gait characteristics using only force-moment measurements from the walker's handles. The passively derived gait characteristics of 22 subjects were validated against motion capture gait analysis. The force-moment based heel initial contact detection algorithm have produced a high level of concordance with heel initial contacts detected by a human inspecting the heel marker data sets of the Vicon video capture system. The algorithm has demonstrated 97% sensitivity and 98% specificity with a narrow 95% confidence interval of ±1% during all experiments, which included five navigational scenarios. Temporal error in detecting the instances of heel initial contacts were within 5.27 ± 3.66% of the overall stride time obtained from Vicon when the subjects walked in a straight line, whereas the toe-off instance estimates were within 5.18 ± 2.75% of the gait cycle. The errors in determining the duration of stride time, single support, and double support were within 5.86 ± 2.49%, 5.24 ± 2.29%, and 4.34 ± 2.13% of the gait cycle respectively. The stride time estimated, using the method presented here, correlated well with stride time computations based on visual inspection of Vicon's data, Pearson correlation coefficient r = 0.86 for straight line segments. However, absolute errors were too high to estimate the single and double support phases with acceptable accuracy. The potential application of the instrumented walker and the method presented here is longitudinal basic gait assessment that can be performed outside of the conventional gait labs.

Gait Analysis in Rotational Acetabular Osteotomy

A study on early weight-bearing after rotational acetabular osteotomy (RAO) was performed in our hospital. In this study, gait analysis was performed on 27 patients (all females; mean age 37 years, range 12-58 years) who underwent unilateral RAO between 1999 to 2003.The gait was analyzed preoperatively and 3 weeks, 1, 3, 6, and 12 months postoperatively. All the patients underwent a free walking test on a 5-m walkway having a ground reaction force plate (gait scan 8000; Nitta Inc.). The test was carried out for 5 seconds. Single and double support duration (% cycle) was assessed. The normal average value in healthy humans reported by Murray et al. 3) was used during the assessment.The preoperative single support duration was unchanged while the double support duration was increased when compared with that for a normal person. Three weeks post operation, single support duration showed increasing reduction while double support duration showed decreasing reduction. However, single support duration gradually attained the normal average value within 1 year. Double support duration attained the normal average value postoperatively. Thus, it can be concluded that the gait improved post RAO. These results concurred with other studies that also reported pre- and postoperativ results in patients with late weight-bearing post RAO. Given these results, we believe gait characteristics remain unaffected post RAO if early weight-bearing is performed.

変形性股関節症患者の臨床評価と歩行分析の相関について

In this report, gait analysis was performed on 176 patients (mean age 61.1 years) who underwent total hip arthroplasty from March 2003 to June 2004. All patients were tested during free walking along an 5-m walkway in which a ground reaction force plate (gait scan 8000; Nitta, Inc.) was installed. Clinical evaluation was carried out on age, sex, Japanese Orthopaedic Association (JOA) score, OA stage, and limb length discrepancy.Multivariate analysis showed that clinical data associated with single support duration were JOA pain score (p<0.001), JOA gait score (p<0.001), and JOA ROM score (p<0.05). Clinical data associated with double support duration were JOA pain score (p<0.001) and JOA gait score (p<0.001). The results of gait analysis can be used as objective index of hip pain and gait ability.