Associations between gait and clinical parameters in patients with severe knee osteoarthritis: A multiple correspondence analysis

Background

Given the complexity of the gait of patients with knee osteoarthritis, a multiple correspondence analysis may be helpful to optimise the extraction of relevant gait and clinical information. Therefore, the aims of this study are to identify the main associations with clinical and gait biomechanical parameters and to evaluate whether there are more specific knee osteoarthritis groups with different gait profiles.

Methods

Ninety patients with severe knee osteoarthritis and twenty-six healthy individuals participated in this study. Pain and function were assessed with the WOMAC Index; knee joint deformity was assessed by the hip-knee-ankle angle on full-limb radiography; and full body gait analysis was performed with a motion analysis system and force plates.

Findings

Using multiple correspondence analysis, two categories of gait parameters that best explain the gait variance of patients with knee osteoarthritis were highlighted. The forward displacement category is composed of the parameters speed, stride length, hip flexion and knee flexion. The frontal category is composed of the parameters thorax obliquity and knee adductor moments. Moreover, based on these parameters, four distinct gait profiles were identified: two gait profiles were associated with knee varus deformities, increased thorax obliquity and different forward displacements, while two gait profiles were associated with valgus deformities and different forward displacements.

Interpretation

These gait parameters can be used to simplify the characterisation of the gait of the knee osteoarthritis population. Patients in varus profiles increase thorax obliquity on the stance limb and may reduce forward displacement. Patients in valgus profiles, however, only reduce forward displacement.     

Diabetic gait and posture abnormalities: A biomechanical investigation through three dimensional gait analysis

Background

Diabetic sensorimotor polyneuropathy is a long-term diabetic complication. It is involved in the pathogenesis of the diabetic foot, which is a major cause of morbidity and mortality. The study aims to investigate the effects of diabetic polyneuropathy on gait and posture.

Methods

Sixty seven subjects were enrolled: 21 diabetics without polyneuropathy, 26 with polyneuropathy, 20 controls (respectively, mean age 63.8 (SD 5.4), 63.2 (SD 5.6), 59.0 (SD 5.2) years, mean body mass index 26.3 (SD 2.5), 25.6 (SD 3), 24.0 (SD 2.9)). Postural and morphological evaluation and gait analysis were performed. Physical examination, together with a motion capture system synchronized with two force plates and two baropodometric systems were used. We evaluated lower limb mobility, foot deformities, trunk and pelvic posture, knee and heel position, plantar foot arch, three dimensional kinematics and kinetics during gait. The effect of peripheral vascular disease and microangiopathy on trunk and lower limb motion was also evaluated.

Findings

Trunk and lower limb joint mobility (in static and dynamic states) were more reduced in diabetics either with or without polyneuropathy on each plane; however in diabetics with polyneuropathy significantly lower ranges of motion were registered. Furthermore, both groups showed significant reductions in each joint moment and velocity (P ? 0.003) during gait. In presence of both vasculopathy and microangiopathy a further significant reduction (P ? 0.001) was noticed.

Interpretation

Altered gait and posture were found in diabetic patients irrespective of polyneuropathy. This approach may be relevant to predict the risk ulceration before clinically detectable neuropathy.     

Ankle range of motion is key to gait efficiency in adolescents with cerebral palsy

Background

Gait in young people with cerebral palsy is inefficient and there is a lack of relevant indicators for monitoring the problem. In particular, the impact of gait kinematics on gait efficiency is not well documented. The aim of this study is to examine the relationship between gait efficiency, gait kinematics, lower limb muscle strength, and muscular spasticity in adolescents with cerebral palsy.

Methods

Ten ambulatory adolescents with spastic cerebral palsy were recruited. The energy expenditure index during gait, gait kinematics, flexion and extension knee isometric muscle strength, and quadriceps spasticity were assessed.

Findings

Energy expenditure index (1.5 (0.7) beats/m) was strongly correlated with the ankle and knee flexion/extension ranges of motion (r = −0.82, P < 0.01 and r = −0.70, P < 0.02, respectively) and also with maximal plantar flexion (r = 0.74, P < 0.05) during gait. Knee flexion strength was the only strength measurement correlated with energy expenditure index (r = −0.85; P < 0.01).

Interpretation

This study suggests that ankle and knee flexion/extension ranges of motion during gait are key kinematics factors in gait efficiency in adolescents with cerebral palsy.     

Increased power generation in impaired lower extremities correlated with changes in walking speeds in sub-acute stroke patients

Background

Establishing changes in net joint power in the lower extremity of patients during recovery of walking might direct gait training in early stroke rehabilitation. It is hypothesized that (1) net joint power in the lower extremity joints would increase in sub-acute stroke patients following gait rehabilitation, and (2) the improvements in net joint power would be significantly correlated with changes in walking speed.

Methods

Thirteen sub-acute patients (<3 months from stroke onset) participated in the study. All patients completed 6 weeks of gait training (3 weeks of robotic gait training and 3 weeks of physiotherapy). The gait patterns were analyzed using 3D motion analysis before and after training. The assessed variables were; gait speed and the net peak joint power of the ankle plantar flexors, hip extensors, hip flexors, hip abductors, and knee extensors.

Findings

Ankle plantar flexor power in the impaired limb and hip extensor power in the unimpaired limb increased significantly following training (133% and 77%, respectively; P < 0.002). Improvements (from 20% to 133%) in net joint power of the ankle plantar flexors, hip extensors, hip flexors, and hip abductors of the impaired limb and ankle plantar flexors and hip abductors of the unimpaired limb significantly correlated with the recovery of walking speed following training (0.24 m/s to 0.51 m/s) (r = 0.71–0.86).

Interpretation

The findings suggested investigations for strengthening the plantar flexors, hip flexors, hip extensors, and hip abductors concentrically, and knee extensors eccentrically in the impaired limb to determine the effectiveness in improving gait performance.     

Interlimb Coordination During the Stance Phase of Gait in Subjects With Stroke

Objective

To analyze the relation between contralesional and ipsilesional limbs in subjects with stroke during step-to-step transition of walking.

Design

Observational, transversal, analytical study with a convenience sample.

Setting

Physical medicine and rehabilitation clinic.

Participants

Subjects (n=16) with poststroke hemiparesis with the ability to walk independently and healthy controls (n=22).

Interventions

Not applicable.

Main Outcome Measures

Bilateral lower limbs electromyographic activity of the soleus (SOL), gastrocnemius medialis, tibialis anterior, biceps femoris, rectus femoris, and vastus medialis (VM) muscles and the ground reaction force were analyzed during double-support and terminal stance phases of gait.

Results

The propulsive impulse of the contralesional trailing limb was negatively correlated with the braking impulse of the leading limb during double support (r=−.639, P=.01). A moderate functional relation was observed between thigh muscles (r=−.529, P=.035), and a strong and moderate dysfunctional relation was found between the plantar flexors of the ipsilesional limb and the vastus medialis of the contralesional limb, respectively (SOL-VM, r=−.80, P<.001; gastrocnemius medialis-VM, r=−.655, P=.002). Also, a functional moderate negative correlation was found between the SOL and rectus femoris muscles of the ipsilesional limb during terminal stance and between the SOL (r=−.506, P=.046) and VM (r=−.518, P=.04) muscles of the contralesional limb during loading response, respectively. The trailing limb relative impulse contribution of the contralesional limb was lower than the ipsilesional limb of subjects with stroke (P=.02) and lower than the relative impulse contribution of the healthy limb (P=.008) during double support.

Conclusions

The findings obtained suggest that the lower performance of the contralesional limb in forward propulsion during gait is related not only to contralateral supraspinal damage but also to a dysfunctional influence of the ipsilesional limb.     

Changes in gait patterns and muscle activity following total hip arthroplasty: A six-month follow-up

Background

Appropriate gait function is an important determinant of the outcome of total hip arthroplasty and relies on appropriate joint motion and muscle activity. The purpose of this study was to test the hypothesis that 6-month postoperative dynamic joint range of motion, time-distance measures and muscle activity in the operated limb in patients undergoing total hip arthroplasty differ from preoperative levels and are more similar to those observed postoperatively in the contralateral limb and in healthy subjects.

Methods

Basic time-distance gait measurements, knee and hip kinematics and electromyographic activity from eight hip muscles were obtained preoperatively and 6 months postoperatively in 52 patients undergoing total hip arthroplasty and in 24 age-matched healthy subjects during treadmill walking.

Findings

Postoperative dynamic hip range of motion for the operated limb (confidence interval differences [− 3.9°; − 2.3°]) and postoperative knee range of motion for both limbs (operated: [− 8.4°; − 5.6°]; contralateral: [− 8.1°; − 5.3°]) in patients with total hip arthroplasty were significantly lower than values for the control subjects (P < 0.001). Postoperative gait in patients with total hip arthroplasty was more symmetric than preoperative gait. Preoperative and postoperative electromyographic intensities were higher in patients with total hip arthroplasty than values for the control subjects (P < 0.001), and patients had different EMG patterns compared to the control group.

Interpretation

Pre- and postoperative differences not only in hip but also in knee kinematics emphasize the importance of evaluating the dynamic outcome of total hip arthroplasty by assessing joint motion of all lower extremity joints in both legs.     

Effects of unloading bracing on knee and hip joints for patients with medial compartment knee osteoarthritis

Background

Osteoarthritis affects the whole body, thus biomechanical effects on other joints should be considered. Unloading knee braces could be effective for knee osteoarthritis, but their effects on the contralateral knee and bilateral hip joints remain unknown. This study investigated the effects of bracing on the kinematics and kinetics of involved and contralateral joints during gait.

Methods

Nineteen patients with medial compartment knee osteoarthritis were analysed. Kinematics and kinetics of the knee and hip joints in frontal and sagittal planes were measured during walking without and with bracing on the more symptomatic knee.

Findings

The ipsilateral hip in the braced condition showed a lower adduction angle by an average of 2.58° (range, 1.05°–4.16°) during 1%–49% of the stance phase, and a lower abduction moment at the second peak during the stance phase than the hip in the unbraced condition (P < 0.05 and P < 0.005, respectively). With bracing, the contralateral hip showed a more marked peak extension moment and lower abduction moment at the first peak (P < 0.05), and the contralateral knee adduction angle increased by an average of 0.32° (range, 0.21°–0.45°) during 46%–55% of the stance phase (P < 0.05), compared to no bracing.

Interpretation

Unloading bracing modified the contralateral knee adduction angle pattern at a specific time point during gait. It also affected the frontal plane on the ipsilateral hip and the frontal and sagittal planes on the contralateral hip joint. Consideration should be provided to other joints when treating knee osteoarthritis.     

An animal model to evaluate skin–implant–bone integration and gait with a prosthesis directly attached to the residual limb

Background

Despite the number of advantages of bone-anchored prostheses, their use in patients is limited due to the lack of complete skin–implant integration. The objective of the present study was to develop an animal model that would permit both detailed investigations of gait with a bone-anchored limb prosthesis and histological analysis of the skin–implant–bone interface after physiological loading of the implant during standing and walking.

Methods

Full-body mechanics of walking in two cats were recorded and analyzed before and after implantation of a percutaneous porous titanium pylon into the right tibia and attachment of a prosthesis. The rehabilitation procedures included initial limb casting, progressively increasing loading on the implant, and standing and locomotor training. Detailed histological analysis of bone and skin ingrowth into implant was performed at the end of the study.

Findings

The two animals adopted the bone-anchored prosthesis for standing and locomotion, although loads on the prosthetic limb during walking decreased by 22% and 62%, respectively, 4 months after implantation. The animals shifted body weight to the contralateral side and increased propulsion forces by the contralateral hindlimb. Histological analysis of the limb implants demonstrated bone and skin ingrowth.

Interpretation

The developed animal model to study prosthetic gait and tissue integration with the implant demonstrated that porous titanium implants may permit bone and skin integration and prosthetic gait with a bone-anchored prosthesis. Future studies with this model will help optimize the implant and prosthesis properties.     

Home-Based Treadmill Training to Improve Gait Performance in Persons With a Chronic Transfemoral Amputation

Objective

To investigate the effectiveness of a home-based multiple-speed treadmill training program to improve gait performance in persons with a transfemoral amputation (TFA).

Design

Repeated measures.

Setting

Research laboratory.

Participants

Individuals with a TFA (N=8) who had undergone a unilateral amputation at least 3 years prior as a result of limb trauma or cancer.

Intervention

Home-based treadmill walking for a total of 30 minutes a day, 3 days per week for 8 weeks. Each 30-minute training session involved 5 cycles of walking for 2 minutes at 3 speeds.

Main Outcome Measures

Participants were tested pretraining and after 4 and 8 weeks of training. The primary measures were temporal-spatial gait performance (symmetry ratios for stance phase duration and step length), physiological gait performance (energy expenditure and energy cost), and functional gait performance (self-selected walking speed [SSWS], maximum walking speed [MWS], and 2-minute walk test [2MWT]).

Results

Eight weeks of home-based training improved temporal-spatial gait symmetry at SSWS but not at MWS. A relative interlimb increase in stance duration for the prosthetic limb and proportionally greater increases in step length for the limb taking shorter steps produced the improved symmetry. The training effect was significant for the step length symmetry ratio within the first 4 weeks of the program. Energy expenditure decreased progressively during the training with nearly 10% improvement observed across the range of walking speeds. SSWS, MWS, and 2MWT all increased by 16% to 20%.

Conclusions

Home-based treadmill walking is an effective method to improve gait performance in persons with TFA. The results support the application of training interventions beyond the initial rehabilitation phase, even in individuals considered highly functional.     

Effect of Overground Training Augmented by Mental Practice on Gait Velocity in Chronic,Incomplete Spinal Cord Injury

Objective

To compare the efficacy of a regimen combining mental practice (MP) with overground training (OT) with the efficacy of a regimen consisting of OT only on gait velocity and lower extremity motor outcomes in individuals with chronic (>12mo postinjury), incomplete spinal cord injury (SCI).

Design

Randomized, controlled, single-blinded study.

Setting

Outpatient rehabilitation laboratories.

Participants

Subjects with chronic, incomplete SCI (N=18).

Interventions

Subjects were randomly assigned to receive (1) OT only, occurring 3d/wk for 8 weeks; or (2) OT augmented by MP (MP + OT), during which randomly assigned subjects listened to an MP audio recording directly after OT sessions.

Main Outcome Measures

Subjects were administered a test of gait velocity as well as the Tinetti Performance Oriented Mobility Assessment, Spinal Cord Injury Independence Measure, and Satisfaction With Life Scale on 2 occasions before intervention, 1 week after intervention, and 12 weeks after intervention.

Results

A significant increase in gait velocity was exhibited across subjects at both 1 week posttherapy (P=.005) and at 12 weeks posttherapy (P=.006). However, no differences were seen in intervention response at either 1 or 12 weeks postintervention among subjects in the MP + OT group versus the OT-only group.

Conclusions

OT was associated with significant gains in gait velocity, and these gains were not augmented by further addition of MP.     

Biomechanical mechanisms of toe-out gait performance in people with and without knee osteoarthritis

Background

Toe-out gait modification (increased toe-out angle) has been proposed to decrease medial knee joint loading and slow disease progression in patients with knee osteoarthritis. However, the manner in which toe-out gait modification is performed is unknown. The purposes of this study were to assess the biomechanical strategies of achieving a toe-out gait, and to compare these strategies between older individuals with knee osteoarthritis and young, healthy individuals.

Methods

Lower limb biomechanics were evaluated for ten patients with knee osteoarthritis and for ten young, healthy individuals during treadmill walking. Two trials, consisting of natural gait followed by a ten degree increase in toe-out angle were performed. Transverse plane rotations of the thigh, shank and foot segments were calculated and compared between walking conditions and groups.

Findings

External rotation changes with toe-out were significantly different between the thigh and shank, and thigh and foot (P < 0.001), but not between the shank and foot (P = 0.48). External rotation at each segment was not significantly different (P > 0.05) between groups, with the exception of thigh rotation during natural gait (P = 0.04).

Interpretation

Current findings suggest that increased toe-out gait is primarily achieved through rotation of the shank and foot, with less contribution from the thigh, and those individuals with knee osteoarthritis perform a toe-out gait biomechanically similar to young, healthy individuals. Gait modification programs should address individuals' limitations, such as joint stiffness, to ensure functional performance of toe-out gait modification.     

Effect of an anterior-sloped brace joint on anterior tibial translation and axial tibial rotation: A motion analysis study

Background

Anterior tibial translation and axial tibial rotation are major biomechanical factors involved in anterior cruciate ligament injuries. This study sought to evaluate a brace prototype designed with an anterior-sloped joint, in terms of its efficacy in attenuating anterior tibial translation and axial tibial rotation during landing, using a motion analysis approach.

Methods

Ten healthy male subjects performed single-leg landing tasks from a 0.6-m height with and without the brace prototype. Ground reaction force and kinematics data were obtained using a motion-capture system and force-plates. Anterior tibial translation and axial tibial rotation were determined based on tibial and femoral marker reference frames. Vertical and anterior–posterior ground reaction forces, hip, knee and ankle joint range-of-motions and angular velocities, anterior tibial translation and axial tibial rotation were compared between unbraced and braced conditions using Wilcoxon signed-rank test.

Findings

We found no significant difference in peak vertical and anterior–posterior ground reaction forces (p = 0.770 and p = 0.332 respectively) between unbraced and braced conditions. Knee joint range-of-motion and angular velocity were lower (p = 0.037 and p = 0.038 respectively) for braced condition than unbraced condition. Anterior tibial translation and axial tibial rotation were reduced (p = 0.027 and p = 0.006 respectively) in braced condition, compared to unbraced condition.

Interpretation

The anterior-sloped brace joint helps to attenuate anterior tibial translation and axial tibial rotation present in the knee joint during landing. It is necessary to test the brace prototype in a sporting population with realistic sports landing situations in order to assess its effectiveness in lowering anterior cruciate ligament injury risk.     

A biomechanical analysis of trunk and pelvis motion during gait in subjects with knee osteoarthritis compared to control subjects

Background

Trunk lean over the stance limb during gait has been linked to a reduction in the knee adduction moment, which is associated with joint loading. We examined differences in knee adduction moments and frontal plane trunk lean during gait between subjects with knee osteoarthritis and a control group of healthy adults.

Methods

Gait analysis was performed on 80 subjects (40 osteoarthritis). To define lateral trunk lean two definitions were used. The line connecting the midpoint between two reference points on the pelvis and the midpoint between the acromion processes was projected onto the lab frontal plane and the pelvis frontal plane. Pelvic tilt was also measured in the frontal plane as the angle between the pelvic and lab coordinate systems. Angles were calculated across the stance phase of gait. We analyzed the data, (i) by extracting discrete parameters (mean and peak) waveform values, and (ii) using principal component analysis to extract shape and magnitude differences between the waveforms.

Findings

Osteoarthritis subjects had a higher knee adduction moment than the control group (α = 0.05). Although the discrete parameters for trunk lean did not show differences between groups, principal component analysis did detect characteristic waveform differences between the control and osteoarthritis groups.

Interpretation

A thorough biomechanical analysis revealed small differences in the pattern of motion of the pelvis and the trunk between subjects with knee osteoarthritis and control subjects; however these differences were only detectable using principal component analysis.     

Preservation of the first rocker is related to increases in gait speed in individuals with hemiplegia and AFO

Background

Changes in impulse during the first rocker (braking force) and third rocker (propulsion force) may affect changes in gait speed after orthotic intervention. The purpose of this investigation was to objectively measure changes in impulse during double support and correlate those findings to changes in gait speed with and without ankle foot orthosis in individuals with hemiplegia.

Methods

Fifteen adults with stroke-related hemiplegia walked with and without ankle foot orthosis while foot pressure data was collected bilaterally. Outcome measures included: gait cycle time (s), mean force (N), and impulse (Ns) in the wholefoot, hindfoot, forefoot, and toe box during initial double support and terminal double support.

Findings

Time significantly decreased during the entire gait cycle, initial double support, and terminal double support, with the ankle foot orthosis. During initial double support, affected limb impulse significantly decreased with the ankle foot orthosis in the wholefoot (P = 0.016), and hindfoot (P = 0.006), and hindfoot impulse % change and gait speed % change were significantly correlated (P = 0.007). During terminal double support, affected limb impulse was not significantly different in the wholefoot or forefoot and these changes were not significantly correlated to gait speed.

Interpretation

Previous research found that orthotics increase gait speed in individuals with hemiplegia. This research suggests that the increase in speed is not due to increased propulsive forces at the end of terminal double support, but due to decreased braking forces during initial double support. Therefore, the orthosis preserved the first ankle rocker and provided a more efficient weight acceptance which positively affected gait speed.     

Longitudinal changes in transtibial amputee gait characteristics when negotiating a change in surface height during continuous gait

Background

Negotiating a raised surface during continuous gait is an important activity of daily living and is a potentially hazardous task with regards to trips, falls and fall-related injury. However, it is not known how recent transtibial amputees adapt to performing stepping gait tasks in the 6-month period following discharge from rehabilitation.

Methods

Recent transtibial amputees performed continuous gait trials, stepping onto and from a raised surface walkway representing the height of a street kerb, whilst kinematic and kinetic data were recorded at one, three and six months post-discharge from rehabilitation.

Findings

Walking speed increased when stepping down (p = 0.04) and was invariant across the study period when stepping up. At one month post-discharge, participants displayed an affected lead limb preference (90.8%) when stepping down and an intact lead limb preference (70.0%) when stepping up, although these lead limb preferences diminished over time. Participants spent more time in stance on the intact limb compared to the affected limb in both stepping down (trail limb) (p = 0.01) and stepping up (lead and trail limbs) (p = 0.05). Participants displayed significantly greater joint mobility and power bursts in the intact trail limb when stepping down and in the intact lead limb when stepping up.

Interpretation

Transtibial amputees prefer to exploit intact limb function to a greater extent, although over time, the means by which this occurs changes which affects the initial lead limb preferences. The results from the current study enable future evidence-based therapeutic and prosthetic interventions to be designed that improve transtibial amputee stepping gait.     

Differences in lumbopelvic motion between people with and people without low back pain during two lower limb movement tests

Background

Clinical data suggest that active limb movements may be associated with early lumbopelvic motion and increased symptoms in people with low back pain.

Methods

Forty-one people without low back pain who did not play rotation-related sports and 50 people with low back pain who played rotation-related sports were examined. Angular measures of limb movement and lumbopelvic motion were calculated across time during active knee flexion and active hip lateral rotation in prone using a three-dimensional motion capture system. Timing of lumbopelvic motion during the limb movement tests was calculated as the difference in time between the initiation of limb movement and lumbopelvic motion normalized to limb movement time.

Findings

During knee flexion and hip lateral rotation, people with low back pain demonstrated a greater maximal lumbopelvic rotation angle and earlier lumbopelvic rotation, compared to people without low back pain (P < 0.05).

Interpretation

The data suggest that people with low back pain who play rotation-related sports may move their lumbopelvic region to a greater extent and earlier during lower limb movements than people without low back pain. Because people perform many of their daily activities in early to midranges of joint motion the lumbopelvic region may move more frequently across the day in people with low back pain. The increased frequency may contribute to increased lumbar region tissue stress and potentially low back pain symptoms. Lower limb movements, therefore, may be important factors related to the development or persistence of low back pain.     

Between-Limb Kinematic Asymmetry During Gait in Unilateral and Bilateral Mild to Moderate Knee Osteoarthritis

Objective

To compare lower-limb kinematic asymmetries during gait in individuals with unilateral and bilateral symptomatic osteoarthritis and controls.

Design

Cross-sectional.

Setting

Laboratory.

Participants

Participants (N=54) had symptomatic unilateral (n=18) or bilateral (n=18) knee osteoarthritis. Healthy controls were sex- and age-matched and similar in height and weight to osteoarthritis groups (n=18).

Intervention

Three-dimensional motion analysis was conducted while participants walked on a treadmill at 1.1m/s.

Main Outcome Measures

Maximum joint angles and velocities of the knee and hip during stance, knee flexion, knee adduction, and hip adduction at initial contact, pelvic drop, stride length, and average toe out.

Results

There was a significant limb effect for knee flexion at initial contact (P=.01). The bilateral osteoarthritis group demonstrated the largest between-limb asymmetry (2.83°; 95% confidence interval, .88–4.78; effect size [ES]=.67). The bilateral osteoarthritis group also displayed tendencies toward between-limb asymmetry in hip adduction at initial contact and peak knee adduction during stance; ESs were small (ES=.33 and .48). Lower-limb kinematics was symmetrical in the control and unilateral knee osteoarthritis groups.

Conclusions

Between-limb asymmetries are present even at mild to moderate stages of knee osteoarthritis. During this stage, between-limb asymmetry appears to be more prevalent in patients with bilateral symptomatic disease, suggesting that patients with unilateral disease maintain kinematic symmetry for longer in the knee osteoarthritis process. Further, early treatment strategies should target the restoration of gait symmetry and involve kinematics changes in both lower limbs. Future research is needed to determine the efficacy of such strategies with respect to kinematic asymmetry, pain, and disease progression.     

Gait parameters and stride-to-stride variability during familiarization to walking on a split-belt treadmill

Background

Subjects unfamiliar to walking on a split-belt treadmill may initially demonstrate an altered gait pattern or increased variability of gait parameters. While previous investigations have examined kinematic variables associated with familiarization time, the objective of this study was to determine the familiarization period required to obtain the most reproducible gait pattern through the assessment of kinetic, kinematic and spatio-temporal parameters during a single session of treadmill walking.

Methods

Eleven healthy subjects participated in a single bout of treadmill walking which lasted 9 min. Kinematic and kinetic data were collected from the first 30 s of each minute, beginning when the treadmill reached full speed. Means and standard deviations for knee flexion at heel strike, ground reaction forces, step width and step length were obtained to examine the changes in each variable over the 9 min. Mean r² values were evaluated for changes in variability from one stride to the subsequent stride for sagittal plane hip, knee and ankle joint angles and moments, as well as for vertical and horizontal ground reaction forces.

Findings

Significant reductions in variability were found for vertical and horizontal ground reaction forces, knee flexion at heel strike and step length over 9 min. Only step width showed a change in the mean value across trials. There were no increases in r² values after the 5th min for any of the gait variables.

Interpretation

The results suggest that in order to collect accurate data for gait analysis, subjects should be familiarized to the split-belt treadmill for at least 5 min prior to data collection.     

The effects of neuromuscular training on the gait patterns of ACL-deficient men and women

Background

Anterior cruciate ligament rupture is the most common knee ligament injury sustained by active individuals, and the relative injury risk is sex-specific. Women not only demonstrate an increased risk for injury, but also a poorer response following ligament rupture. Perturbation training has shown positive results in healthy females, but gender-specific responses to training after injury have not been evaluated. The purpose of this investigation was to describe the effects of perturbation training on the gait characteristics of male and female non-copers.

Methods

Biomechanical data were collected before and after training on 12 male and nine female non-copers using standard motion analysis techniques. Subjects walked at a consistent, self-selected speed over an embedded force plate. Data from both limbs were post-processed and analyzed using a mixed model analysis of variance and minimal clinically important differences to compare the limb behaviors of men and women.

Findings

Prior to training, only women demonstrated significant hip joint excursion asymmetry (ES = 1.03; P = 0.009). Minimal clinically important difference values showed that the involved limb of the women had reduced hip and knee flexion angles and moments, truncated knee excursions, and increased hip excursions when compared to their own uninvolved limb and the limbs of the male non-copers. Following training, only knee extensor moment values exceeded the minimal clinically important differences in women.

Interpretation

Female non-copers demonstrated unique movement strategies following injury and perturbation training. Women may be a meaningful subgroup of non-copers, and future investigations should consider the effects of gender in the outcomes of non-copers.     

Slowed Down: Response Time Deficits in Well-Recovered Subjects With Incomplete Spinal Cord Injury

Objective

To quantify remaining motor deficits in well-recovered subjects with incomplete spinal cord injury.

Design

Case-control study.

Setting

Spinal cord injury center of a university hospital.

Participants

Out of a volunteer sample, we recruited 15 subjects with incomplete paraplegia (mean age, 50y; 67% men; neurologic level from T4 to L4; mean time since injury, 6.3y) and close-to-normal walking pattern. They were compared with 15 age- and sex-matched controls.

Interventions

Not applicable.

Main Outcome Measures

Response time and its 4 subparts, processing time, conduction time, motor time, and movement time. These were assessed with an electromyogram-supported lower-limb response time task and single-pulse transcranial magnetic stimulation to measure the motor-evoked potential latency of the M. tibialis anterior. In addition, participants were tested for lower-extremity muscle strength, gait capacity, visual acuity, and upper-extremity response time.

Results

Well-recovered subjects with incomplete paraplegia still suffered from deficits in conduction and movement time, whereas their processing and motor times were essentially normal. In addition, these patients showed delayed movement times of the upper limb, even if their injury was located in the thoracic or lumbar region.

Conclusions

Well-recovered patients with incomplete paraplegia still experience difficulties with quick and accurate movements. Furthermore, combining transcranial magnetic stimulation, electromyogram, and a response time task proved useful for investigating deficits in executing fast and accurate movements.