Treadmill-based locomotor training with leg weights to enhance functional ambulation in people with chronic stroke: a pilot study

Design and Validation of a Pancake Style Planetary Gearbox for an Eddy Current-Based Wearable Gait Training Robot

Eddy current brakes have been recently used for functional resistance training in individuals with neurological and orthopaedic disorders. These devices consist of a gearbox, a conductive disc, and permanent magnets that can be moved relative to the disc to alter resistance. However, current devices use a commercial planetary gearbox with a tall profile that sticks out from the leg, which affects wearability. This is coupled with the large system inertia, which together impedes potential device transition to clinical and in-home use. In this study, we developed a low-profile, pancake-style planetary gearbox that greatly reduces the protrusion of the device from the leg. We performed a design analysis and optimization to minimize the thickness and inertia of the device while ensuring that it could withstand the maximum expected torque (50 Nm). We then performed human subjects experiments to examine the effectiveness of our new design for functional resistance training. The results indicated that all leg muscles showed a significant increase in activation during resisted conditions. There were also significant after-effects on medial hamstring activation. These results indicate that the new design is a feasible method for functional resistance training and may have a potential clinical value in gait rehabilitation.

Effectiveness of an 8-week overground walking with paretic lower limb loading on spatiotemporal gait parameters and motor function among chronic stroke survivors: a protocol for randomised controlled trial

BACKGROUND

Post-stroke gait deviations contribute to significant functional disability, impaired walking ability and poor quality of life. Prior studies suggest that gait training with paretic lower limb loading may improve gait parameters and walking ability in post-stroke. However, most gait training methods used in these studies are not readily available, and studies using cheaper methods are limited.

OBJECTIVE

The purpose of this study is to describe a protocol for a randomised controlled trial on the effectiveness of an 8-week overground walking with paretic lower limb loading on spatiotemporal gait parameters and motor function among chronic stroke survivors.

METHODS

This is a two-center, single-blind, two-arm parallel randomised controlled trial. Forty-eight stroke survivors with mild to moderate disability will be recruited from two tertiary facilities and randomly assigned into two intervention arms; overground walking with paretic lower limb loading or overground walking without paretic lower limb loading in a 1:1 ratio. All interventions will be administered thrice weekly for 8 weeks. Primary outcomes will be step length and gait speed whereas the secondary outcomes will include step length symmetry ratio, stride length, stride length symmetry ratio, stride width, cadence and motor function. All outcomes will be assessed at baseline, 4, 8 and 20 weeks after the start of intervention.

DISCUSSION

This will be the first randomised controlled trial to report the effects of overground walking with paretic lower limb loading on spatiotemporal gait parameters and motor function among chronic stroke survivors from low-resource setting.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05097391. Registered on 27 October 2021.

Functional resistance training methods for targeting patient-specific gait deficits: A review of devices and their effects on muscle activation, neural control, and gait mechanics

BACKGROUND

Injuries to the neuromusculoskeletal system often result in weakness and gait impairments. Functional resistance training during walking-where patients walk while a device increases loading on the leg-is an emerging approach to combat these symptoms. However, there are many methods that can be used to resist the patient, which may alter the biomechanics of the training. Thus, all methods may not address patient-specific deficits.

METHODS

We performed a comprehensive electronic database search to identify articles that acutely (i.e., after a single training session) examined how functional resistance training during walking alters muscle activation, gait biomechanics, and neural plasticity. Only articles that examined these effects during training or following the removal of resistance (i.e., aftereffects) were included.

FINDINGS

We found 41 studies that matched these criteria. Most studies (24) used passive devices (e.g., weighted cuffs or resistance bands) while the remainder used robotic devices. Devices varied on if they were wearable (14) or externally tethered, and the type of resistance they applied (i.e., inertial [14], elastic [8], viscous [7], or customized [12]). Notably, these methods provided device-specific changes in muscle activation, biomechanics, and spatiotemporal and kinematic aftereffects. Some evidence suggests this training results in task-specific increases in neural excitability.

INTERPRETATION

These findings suggest that careful selection of resistive strategies could help target patient-specific strength deficits and gait impairments. Also, many approaches are low-cost and feasible for clinical or in-home use. The results provide new insights for clinicians on selecting an appropriate functional resistance training strategy to target patient-specific needs.

Motor slacking during resisted treadmill walking: Can visual feedback of kinematics reduce this behavior?

BACKGROUND

Functional resistance training is frequently applied to rehabilitate individuals with neuromusculoskeletal injuries. It is performed by applying resistance in conjunction with a task-specific training, such as walking. However, the benefits of this training may be limited by motor slacking, a phenomenon in which the human body attempts to reduce muscle activation levels or movement excursions to minimize metabolic- or movement-related costs. While kinematic feedback could reduce one's tendency to minimize effort during training, this has not been verified experimentally.

RESEARCH QUESTION

Does functional resistance training during walking lead to motor slacking, and can techniques such as visual feedback be used to reduce these effects?

METHODS

Fourteen able-bodied individuals participated in this experiment. Participants were trained by walking on a treadmill while a bidirectional resistance was applied to the knee using a robotic knee exoskeleton. During training, participants were either instructed to walk in a manner that felt natural or were provided real-time visual feedback of their kinematics. Electromyography and knee kinematics were measured to determine if adding resistance to the limb induced slacking and if feedback could reduce slacking behavior. Kinematic aftereffects were measured after training bouts to gauge adaptation.

RESULTS

Functional resistance training without feedback significantly reduced knee flexion when compared to baseline walking, indicating that participants were slacking. This reduction in knee flexion did not improve with continued training. Providing visual feedback of knee joint kinematics during training significantly increased knee muscle activation and kinematic aftereffects.

SIGNIFICANCE

The findings indicate that individuals are susceptible to motor slacking during functional resistance training, which could affect outcomes of this training. However, motor slacking can be reduced if training is provided in conjunction with a feedback paradigm. This finding underscores the importance of using additional methods that externally motivate motor adaptation when the body is not intrinsically motivated to do so.

Design and Preliminary Assessment of a Passive Elastic Leg Exoskeleton for Resistive Gait Rehabilitation

OBJECTIVE

This article aimed to develop a unique exoskeleton to provide different types of elastic resistances (i.e., resisting flexion, extension, or bidirectionally) to the leg muscles during walking.

METHODS

We created a completely passive leg exoskeleton, consisting of counteracting springs, pulleys, and clutches, to provide different types of elastic resistance to the knee. We first used a benchtop setting to calibrate the springs and validate the resistive capabilities of the device. We then tested the device's ability to alter gait mechanics, muscle activation, and kinematic aftereffects when walking on a treadmill under the three resistance types.

RESULTS

Benchtop testing indicated that the device provided a nearly linear torque profile and could be accurately configured to alter the angle where the spring system was undeformed (i.e., the resting position). Treadmill testing indicated the device could specifically target knee flexors, extensors, or both, and increase eccentric loading at the joint. Additionally, these resistance types elicited different kinematic aftereffects that could be used to target user-specific spatiotemporal gait deficits.

CONCLUSION

These results indicate that the elastic device can provide various types of targeted resistance training during walking.

SIGNIFICANCE

The proposed elastic device can provide a diverse set of resistance types that could potentially address user-specific muscle weaknesses and gait deficits through functional resistance training.

Does robot-assisted gait training improve mobility, activities of daily living and quality of life in stroke? A single-blinded, randomized controlled trial

The purpose of this study was to investigate the effects of robot-assisted gait training (RAGT) on mobility, activities of daily living (ADLs), and quality of life (QoL) in stroke rehabilitation. Fifty-one stroke patients randomly assigned to Group 1, Group 2, and Group 3 received conventional training (CT) plus RAGT, CT, and RAGT, respectively. The training duration was for 6 weeks. The primary outcome measures were the Barthel Index (BI), Stroke Specific Quality of Life Scale (SS-QOL), 6-Minute Walk Test (6-MWT), and Stair Climbing Test (SCT). The secondary outcomes were Fugl Meyer Assessment-Lower Extremity (FMA-LE), Comfortable 10-m Walk Test (CWT), Fast 10-m Walk Test (FWT), and Rate of Perceived Exertion (RPE). The mean change in all the primary [BI (p = 0.001), 6-MWT (p = 0.001), SS-QOL (p < 0.0001), and SCT (p = 0.004)] and except the FWT (p = 0.354) all the other secondary outcomes [FMA-LE (p = 0.049), CWT (p = 0.025) and RPE (p = 0.023)] improved significantly between the three groups. In the subgroup analysis, BI, 6-MWT, SS-QOL, and SCT improved significantly in Group 1 compared to Group 2 and Group 3 (p < 0.016). However, FMA-LE, CWT, and the RPE significantly improved in Group 1 compared to Group 2 and, also, only CWT improved significantly in Group 1 compared to Group 3 (p = 0.011). In a subgroup analysis of the primary and secondary outcome measures, there were no significant differences in Group 2 compared to Group 3 (p > 0.05). While combined training leads to more improvement in mobility, ADLs, and QoL, CT showed a similar improvement compared to the RAGT in stroke patients.

Effect of Underwater Treadmill Gait Training With Water-Jet Resistance on Balance and Gait Ability in Patients With Chronic Stroke: A Randomized Controlled Pilot Trial

Objective: The purpose of this study was to determine the effects of underwater treadmill gait training with water-jet resistance and underwater treadmill gait training with ankle weights on balance and gait abilities in chronic stroke patients.

Methods: Twenty-two inpatients and outpatients with stroke-induced impairments were randomly assigned into two groups: an underwater treadmill gait training with water-jet resistance group (n = 11) and an underwater treadmill gait training with ankle weights group (n = 11). Participants received conventional physical therapy for 30 min and underwater treadmill gait training with water-jet resistance or ankle weights for 30 min. Intervention was performed 5 days a week for 4 weeks. The Balance System SD was used to assess static and dynamic balance. The GAITRite system was used to assess gait velocity, cadence, step length, stride length, and swing phase. All measurements were performed at the beginning of the study and 4 weeks after the intervention.

Results: The water-jet resistance group and ankle weights group showed significant improvement in static balance (P < 0.00 vs. P = 0.01), dynamic balance (P < 0.00 vs. P = 0.57), gait velocity (P < 0.00 vs. P = 0.037), cadence (P < 0.00 vs. P = 0.001), step length (P < 0.00 vs. P = 0.003), stride length (P < 0.00 vs. P = 0.023), and swing phase (P < 0.00 vs. P < 0.00). However, the static and dynamic balance ability score (P < 0.00), gait velocity (P < 0.00), cadence (P < 0.00), step length (P < 0.00), stride length (P < 0.00), and swing phase (P = 0.023) in the group that received underwater treadmill gait training with water-jet resistance improved more than in the group that received underwater treadmill gait training with ankle weights.

Conclusions: Our results demonstrated that underwater treadmill gait training with water-jet resistance is effective in improving static and dynamic balance as well as gait abilities in chronic stroke patients. Thus, training using underwater treadmill gait training with water-jet resistance may be useful in facilitating active rehabilitation in chronic stroke patients.

Functional resistance training during walking: Mode of application differentially affects gait biomechanics and muscle activation patterns

BACKGROUND

Task-specific loading of the limbs-termed as functional resistance training-is commonly used in gait rehabilitation; however, the biomechanical and neuromuscular effects of various forms of functional resistance training have not been studied systematically. This information is crucial for correctly selecting the appropriate mode of functional resistance training when treating individuals with gait disorders.

RESEARCH QUESTION

To comprehensively evaluate the biomechanical (i.e., joint moment and power) and muscle activation changes with different forms of functional resistance training that are commonly used in clinics and research using biomechanical simulation-based analyses.

METHODS

We developed simulations of functional resistance training during walking using OpenSim (Gait2354, 23 degrees of freedom and 54 muscles) and custom MATLAB scripts. We investigated five modes of functional resistance training that have been commonly used in clinics or in research: (1) a weight attached at the ankle, (2) an elastic band attached at the ankle, (3) a viscous device attached to the hip and knee, (4) a weight attached at the pelvis, and (5) a constant backwards pulling force at the pelvis. Lower-extremity joint moments and powers were computed using inverse dynamics and muscle activations were estimated using computed muscle control while walking with each device under multiple resistance levels: normal walking with no resistance, and walking with 30, 60, and 90 Newtons of resistance.

RESULTS

The results indicate that the way in which resistance is applied during gait training differentially affects the internal joint moments, powers, and muscle activations as well as the joints and phase of the gait cycle where the resistance was experienced.

SIGNIFICANCE

The results highlight the importance of understanding the joints and muscles that are targeted by various modes of functional resistance training and carefully choosing the best mode of training that meets the specific therapeutic needs of the patient.

A wearable resistive robot facilitates locomotor adaptations during gait

BACKGROUND

Robotic-resisted treadmill walking is a form of task-specific training that has been used to improve gait function in individuals with neurological injury, such as stroke, spinal cord injury, or cerebral palsy. Traditionally, these devices use active elements (e.g., motors or actuators) to provide resistance during walking, making them bulky, expensive, and less suitable for overground or in-home rehabilitation. We recently developed a low-cost, wearable robotic brace that generates resistive torques across the knee joint using a simple magnetic brake. However, the possible effects of training with this device on gait function in a clinical population are currently unknown.

OBJECTIVE

The purpose of this study was to test the acute effects of resisted walking with this device on kinematics, muscle activation patterns, and gait velocity in chronic stroke survivors.

METHODS

Six stroke survivors wore the resistive brace and walked on a treadmill for 20 minutes (4×5 minutes) at their self-selected walking speed while simultaneously performing a foot trajectory-tracking task to minimize stiff-knee gait. Electromyography, sagittal plane gait kinematics, and overground gait velocity were collected to evaluate the acute effects of the device on gait function.

RESULTS

Robotic-resisted treadmill training resulted in a significant increase in quadriceps and hamstring EMG activity during walking. Significant aftereffects (i.e., improved joint excursions) were also observed on the hip and knee kinematics, which persisted for several steps after training. More importantly, training resulted in significant improvements in overground gait velocity. These results were consistent in all the subjects tested.

CONCLUSION

This study provides preliminary evidence indicating that robotic-resisted treadmill walking using our knee brace can result in meaningful biomechanical aftereffects that translate to overground walking.

Non-gait-specific intervention for the rehabilitation of walking after SCI: role of the arms

Arm movements modulate leg activity and improve gait efficiency; however, current rehabilitation interventions focus on improving walking through gait-specific training and do not actively involve the arms. The goal of this project was to assess the effect of a rehabilitation strategy involving simultaneous arm and leg cycling on improving walking after incomplete spinal cord injury (iSCI). We investigated the effect of 1) non-gait-specific training and 2) active arm involvement during training on changes in over ground walking capacity. Participants with iSCI were assigned to simultaneous arm-leg cycling (A&L) or legs only cycling (Leg) training paradigms, and cycling movements were assisted with electrical stimulation. Overground walking speed significantly increased by 0.092 ± 0.022 m/s in the Leg group and 0.27 ± 0.072m/s in the A&L group after training. Whereas the increases in the Leg group were similar to those seen after current locomotor training strategies, increases in the A&L group were significantly larger than those in the Leg group. Walking distance also significantly increased by 32.12 ± 8.74 m in the Leg and 91.58 ± 36.24 m in the A&L group. Muscle strength, sensation, and balance improved in both groups; however, the A&L group had significant improvements in most gait measures and had more regulated joint kinematics and muscle activity after training compared with the Leg group. We conclude that electrical stimulation-assisted cycling training can produce significant improvements in walking after SCI. Furthermore, active arm involvement during training can produce greater improvements in walking performance. This strategy may also be effective in people with other neural disorders or diseases. NEW & NOTEWORTHY This work challenges concepts of task-specific training for the rehabilitation of walking and encourages coordinated training of the arms and legs after spinal cord injury. Cycling of the legs produced significant improvements in walking that were similar in magnitude to those reported with gait-specific training. Moreover, active engagement of the arms simultaneously with the legs generated nearly double the improvements obtained by leg training only. The cervico-lumbar networks are critical for the improvement of walking.

The role of movement errors in modifying spatiotemporal gait asymmetry post stroke: a randomized controlled trial

OBJECTIVE

Current rehabilitation to improve gait symmetry following stroke is based on one of two competing motor learning strategies: minimizing or augmenting symmetry errors. We sought to determine which of those motor learning strategies best improves overground spatiotemporal gait symmetry.

DESIGN

Randomized controlled trial.

SETTING

Rehabilitation research lab.

SUBJECTS

In all, 47 participants (59 ± 12 years old) with chronic hemiparesis post stroke and spatiotemporal gait asymmetry were randomized to error augmentation, error minimization, or conventional treadmill training (control) groups.

INTERVENTIONS

To augment or minimize asymmetry on a step-by-step basis, we developed a responsive, "closed-loop" control system, using a split-belt instrumented treadmill that continuously adjusted the difference in belt speeds to be proportional to the patient's current asymmetry.

MAIN MEASURES

Overground spatiotemporal asymmetries and gait speeds were collected prior to and following 18 training sessions.

RESULTS

Step length asymmetry reduced after training, but stance time did not. There was no group × time interaction. Gait speed improved after training, but was not affected by type of asymmetry, or group. Of those who trained to modify step length asymmetry, there was a moderately strong linear relationship between the change in step length asymmetry and the change in gait speed.

CONCLUSION

Augmenting errors was not superior to minimizing errors or providing only verbal feedback during conventional treadmill walking. Therefore, the use of verbal feedback to target spatiotemporal asymmetry, which was common to all participants, appears to be sufficient to reduce step length asymmetry. Alterations in stance time asymmetry were not elicited in any group.

Effects of treadmill training with load addition on non-paretic lower limb on gait parameters after stroke: A randomized controlled clinical trial

The addition of load on the non-paretic lower limb for the purpose of restraining this limb and stimulating the use of the paretic limb has been suggested to improve hemiparetic gait. However, the results are conflicting and only short-term effects have been observed. This study aims to investigate the effects of adding load on non-paretic lower limb during treadmill gait training as a multisession intervention on kinematic gait parameters after stroke. With this aim, 38 subacute stroke patients (mean time since stroke: 4.5 months) were randomly divided into two groups: treadmill training with load (equivalent to 5% of body weight) on the non-paretic ankle (experimental group) and treadmill training without load (control group). Both groups performed treadmill training during 30min per day, for two consecutive weeks (nine sessions). Spatiotemporal and angular gait parameters were assessed by a motion system analysis at baseline, post-training (at the end of 9days of interventions) and follow-up (40days after the end of interventions). Several post-training effects were demonstrated: patients walked faster and with longer paretic and non-paretic steps compared to baseline, and maintained these gains at follow-up. In addition, patients exhibited greater hip and knee joint excursion in both limbs at post-training, while maintaining most of these benefits at follow-up. All these improvements were observed in both groups. Although the proposal gait training program has provided better gait parameters for these subacute stroke patients, our data indicate that load addition used as a restraint may not provide additional benefits to gait training.

Part 2: Adaptation of Gait Kinematics in Unilateral Cerebral Palsy Demonstrates Preserved Independent Neural Control of Each Limb

Motor adaptation, or alteration of neural control in response to a perturbation, is a potential mechanism to facilitate motor learning for rehabilitation. Central nervous system deficits are known to affect locomotor adaptation; yet we demonstrated that similar to adults following stroke, children with unilateral brain injuries can adapt step length in response to unilateral leg weighting. Here, we extend our analysis to explore kinematic strategies underlying step length adaptation and utilize dynamical systems approaches to elucidate how neural control may differ in those with hemiplegic CP across legs and compared to typically developing controls. Ten participants with hemiplegic CP and ten age-matched controls participated in this study. Knee and hip joint kinematics were analyzed during unilateral weighting of each leg in treadmill walking to assess adaptation and presence and persistence of after-effects. Peak joint angle displacement was used to represent changes in joint angles during walking. We examined baseline and task-specific variability and local dynamic stability to evaluate neuromuscular control across groups and legs. In contrast to controls, children with unilateral CP had asymmetries in joint angle variability and local dynamic stability at baseline, showing increased variability and reduced stability in the dominant limb. Kinematic variability increased and local stability decreased during weighting of ipsilateral and contralateral limbs in both groups compared to baseline. After weight removal both measures returned to baseline. Analogous to the temporal-spatial results, children with unilateral CP demonstrated similar capability as controls to adapt kinematics to unilateral leg weighting, however, the group with CP differed across sides after weight removal with dominant limb after-effects fading more quickly than in controls. The change in kinematics did not completely return to baseline in the non-dominant limb of the CP group, producing a transient improvement in joint angle symmetry. Recent studies demonstrate that neural control of gait is multi-layered with distinct circuits for different types of walking and for each leg. Remarkably, our results demonstrate that children with unilateral brain injury retain these separate circuits for each leg during walking and, importantly, that those networks can be adapted independently from one another to improve symmetry in the short term.

Effect of Aerobic Exercise Interventions on Mobility among Stroke Patients: A Systematic Review

OBJECTIVE

The purpose of this systematic review was to examine studies that examined the effectiveness of aerobic exercise interventions on mobility in long-term stroke survivors.

DESIGN

The authors searched electronic databases for randomized control trials between January 1995 and December 2014 investigating aerobic exercise interventions and mobility in stroke survivors after the subacute phase (>6 mos). Mobility was measured using objective functional fitness tests: 6-minute walk, 10-meter walk, and up-n-go.

RESULTS

Nine randomized control trials that compared aerobic exercise with a control group among stroke survivors (mean age, 56.95-68 yrs) were identified. Aerobic interventions lasted between 2 and 6 mos and primarily involved walking. Using the Comprehensive Meta-analysis software, it was found that two of the three mobility outcomes showed small to moderate effect sizes favoring the aerobic exercise group: 6-minute walk (g = 0.366, P < 0.001) and 10-meter walk (g = 0.411, P = 0.002), while the up-n-go test was not significant (g = -0.150, P = 0.330).

CONCLUSION

These findings demonstrate that stroke survivors may continue to benefit from aerobic exercise after the subacute phase. Future research needs to examine the precise dose and recommendation for aerobic exercise, test other exercise modalities, and use larger samples to thoroughly determine long-term exercise effects on mobility in this population.

Individuals Poststroke Do Not Perceive Their Spatiotemporal Gait Asymmetries as Abnormal

BACKGROUND

Following stroke, spatiotemporal gait asymmetries persist into the chronic phases, despite the neuromuscular capacity to produce symmetric walking patterns. This persistence of gait asymmetry may be due to deficits in perception, as the newly established asymmetric gait pattern is perceived as normal.

OBJECTIVE

The purpose of this study was to determine the effect of usual overground gait asymmetry on the ability to consciously and unconsciously perceive the presence of gait asymmetry in people poststroke.

DESIGN

An observational study was conducted.

METHODS

Thirty people poststroke walked overground and on a split-belt treadmill with the belts moving at different speeds (0%-70% difference) to impose varied step length and stance time asymmetries. Conscious awareness and subconscious detection of imposed gait patterns were determined for each participant, and the asymmetry magnitudes at those points were compared with overground gait.

RESULTS

For both spatial and temporal asymmetry variables, the asymmetry magnitude at the threshold of awareness was significantly greater than the asymmetry present at the threshold of detection or during overground gait. Participants appeared to identify belt speed differences using the type of gait asymmetry they typically exhibited (ie, step length or stance time asymmetries during overground gait).

LIMITATIONS

Very few individuals with severe spatiotemporal asymmetry were tested, and participants were instructed to identify asymmetric belt speeds rather than interlimb movements.

CONCLUSIONS

The data suggest that asymmetry magnitudes need to exceed usual overground levels to reach conscious awareness. Therefore, it is proposed that the spatiotemporal asymmetry that is specific to each participant may need to be augmented beyond what he or she usually has during walking in order to promote awareness of asymmetric gait patterns for long-term correction and learning.

The effects of ankle loads on balance ability during one-leg stance

[Purpose] The purpose of this study was to evaluate the effects of ankle loads on balance ability and to suggest an appropriate load amount. [Subjects and Methods] The 31 healthy subjects randomly put 0%, 1%, and 2% body weight loads on their ankles using a strap, and limit of stability was measured using a Biorescue system. Limits of stability were measured for 10 seconds using their dominant leg in the left, right, forward, and backward directions. [Results] All values for limit of stability increased significantly with the 1% load compared with the 0% load during a one-leg stance. However, all values except for the backward limit of stability showed a significant decrease with the 2% load compared with the 1% load. There was a significant difference between the 0% and 2% loads. [Conclusion] Application of loads on the ankles can be used as a training method for improving balance ability, and to increase efficiency, it is appropriate to apply 1% of the subject’s body weight.

Effects of gait training with horizontal impeding force on gait and balance of stroke patients

[Purpose] The purpose of this study was to investigate the effects of treadmill training with a horizontal impeding force applied to the center of upper body mass on the gait and balance of post-stroke patients. [Subjects and Methods] Twenty-four subjects with hemiplegia less than 3 months after stroke onset were randomly assigned to 2 groups: an applied horizontal impeding force on treadmill training (experimental) group (n = 12), and a control group (n = 12). Both groups walked on a treadmill at a comfortable or moderate speed for 20 minutes per day, 3 sessions per week for 8 weeks after a pre-test. The experimental group also had a horizontal impeding force applied to the center of their upper body mass. [Results] All groups demonstrated significant improvement after 8 weeks compared to baseline measurements. In intra-group comparisons, the subjects’ gait ability (CGS, MGS, cadence, and step length) and balance ability (TUG, BBS, and FRT) significantly improved. In inter-group comparisons, the experimental group’s improvement was significantly better in CGS MGS, cadence, step length, TUG, and BBS, but not in FRT. [Conclusion] Treadmill training was identified as an effective training method that improved gait and balance ability. A horizontal impeding force applied during treadmill training was more effective than treadmill walking training alone at improving the gait and dynamic balance of patients with stroke.

Body weight-supported treadmill training is no better than overground training for individuals with chronic stroke: a randomized controlled trial

BACKGROUND

Body weight-supported treadmill training (BWSTT) has produced mixed results compared with other therapeutic techniques.

OBJECTIVE

The purpose of this study was to determine whether an intensive intervention (intensive mobility training) including BWSTT provides superior gait, balance, and mobility outcomes compared with a similar intervention with overground gait training in place of BWSTT.

METHODS

Forty-three individuals with chronic stroke (mean [SD] age, 61.5 [13.5] years; mean [SD] time since stroke, 3.3 [3.8] years), were randomized to a treatment (BWSTT, n = 23) or control (overground gait training, n = 20) group. Treatment consisted of 1 hour of gait training; 1 hour of balance activities; and 1 hour of strength, range of motion, and coordination for 10 consecutive weekdays (30 hours). Assessments (step length differential, self-selected and fast walking speed, 6-minute walk test, Berg Balance Scale [BBS], Dynamic Gait Index [DGI], Activities-specific Balance Confidence [ABC] scale, single limb stance, Timed Up and Go [TUG], Fugl-Meyer [FM], and perceived recovery [PR]) were conducted before, immediately after, and 3 months after intervention.

RESULTS

No significant differences (α = 0.05) were found between groups after training or at follow-up; therefore, groups were combined for remaining analyses. Significant differences (α = 0.05) were found pretest to posttest for fast walking speed, BBS, DGI, ABC, TUG, FM, and PR. DGI, ABC, TUG, and PR results remained significant at follow-up. Effect sizes were small to moderate in the direction of improvement.

CONCLUSIONS

Future studies should investigate the effectiveness of intensive interventions of durations greater than 10 days for improving gait, balance, and mobility in individuals with chronic stroke.

Effects of traumatic brain injury on locomotor adaptation

BACKGROUND AND PURPOSE

Locomotor adaptation is a form of short-term learning that enables gait modifications and reduces movement errors when the environment changes. This adaptation is critical for community ambulation for example, when walking on different surfaces. While many individuals with traumatic brain injury (TBI) recover basic ambulation, less is known about recovery of more complex locomotor skills, like adaptation. The purpose of this study was to investigate how TBI affects locomotor adaptation.

METHODS

Fourteen adults with TBI and 11 nondisabled comparison participants walked for 15 minutes on a split-belt treadmill with 1 belt moving at 0.7 m/s, and the other at 1.4 m/s. Subsequently, aftereffects were assessed and de-adapted during 15 minutes of tied-belt walking (both belts at 0.7 m/s).

RESULTS

Participants with TBI showed greater asymmetry in interlimb coordination on split-belts than the comparison group. Those with TBI did not adapt back to baseline symmetry, and some individuals did not store significant aftereffects. Greater asymmetry on split-belts and smaller aftereffects were associated with greater ataxia.

DISCUSSION

Participants with TBI were more perturbed by walking on split-belts and showed some impairment in adaptation. This suggests a reduced ability to learn a new form of coordination to compensate for environmental changes. Multiple interacting factors, including cerebellar damage and impairments in higher-level cognitive processes, may influence adaptation post-TBI.

CONCLUSIONS

Gait adaptation to novel environment demands is impaired in persons with chronic TBI and may be an important skill to target in rehabilitation.

VIDEO ABSTRACT AVAILABLE

(See Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A74) for more insights from the authors.

Effects of Progressive Body Weight Support Treadmill Forward and Backward Walking Training on Stroke Patients' Affected Side Lower Extremity's Walking Ability

[Purpose] The purpose of the present study was to examine the effects of progressive body weight supported treadmill forward and backward walking training (PBWSTFBWT), progressive body weight supported treadmill forward walking training (PBWSTFWT), progressive body weight supported treadmill backward walking training (PBWSTBWT), on stroke patients' affected side lower extremity's walking ability. [Subjects and Methods] A total of 36 chronic stroke patients were divided into three groups with 12 subjects in each group. Each of the groups performed one of the progressive body weight supported treadmill training methods for 30 minute, six times per week for three weeks, and then received general physical therapy without any other intervention until the follow-up tests. For the assessment of the affected side lower extremity's walking ability, step length of the affected side, stance phase of the affected side, swing phase of the affected side, single support of the affected side, and step time of the affected side were measured using optogait and the symmetry index. [Results] In the within group comparisons, all the three groups showed significant differences between before and after the intervention and in the comparison of the three groups, the PBWSTFBWT group showed more significant differences in all of the assessed items than the other two groups. [Conclusion] In the present study progressive body weight supported treadmill training was performed in an environment in which the subjects were actually walked, and PBWSTFBWT was more effective at efficiently training stroke patients' affected side lower extremity's walking ability.

Modifications in ankle dorsiflexor activation by applying a torque perturbation during walking in persons post-stroke: a case series

Background

Results obtained in a previous study (Gait Posture 34:358–363, 2011) have shown that, in non-disabled participants, a specific increase in ankle dorsiflexor (Tibialis anterior [TA]) activation can be induced by walking with a torque perturbation that plantarflexes the ankle during the swing phase. After perturbation removal, the increased TA activation persisted temporarily and was associated with a more dorsiflexed ankle during swing. The objective of the present case-series study was to verify if these results can be reproduced in persons post-stroke.

Methods

Six participants who sustained a stroke walked on a treadmill before, during and after exposure to a torque perturbation applied at the ankle by a robotized ankle-foot orthosis. Spatiotemporal gait parameters, ankle and knee kinematics, and the electromyographic activity of TA and Soleus were recorded. Mean amplitude of the TA burst located around toe off and peak ankle dorsiflexion angle during swing were compared across the 3 walking periods for each participant.

Results

At the end of the walking period with the perturbation, TA mean amplitude was significantly increased in 4 of the 6 participants. Among these 4 participants, modifications in TA activation persisted after perturbation removal in 3 of them, and led to a statistically significant increase in peak dorsiflexion during swing.

Clinical implications

This approach may be helpful to evaluate the residual adaptive capacity in the ankle dorsiflexors after a stroke and guide decision-making for the selection of optimal rehabilitation interventions. Future work will investigate the clinical impact of a multiple-session gait training based on this approach in persons presenting a reduced ankle dorsiflexion during the swing phase of walking.

The Effect of Treadmill-based Incremental Leg Weight Loading Training on the Balance of Stroke Patients

[Purpose] The purpose of this study was to examine the effect of treadmill-based gait training using incremental weight loading on the ankle of the affected side on hemiplegic stroke patients’ balance. [Subjects] In this study, 30 hemiplegic stroke patients were randomly divided into an incremental weight load group (IWLG, n=15) and a no-load group (NLG, n=15). [Methods] The IWLG performed gait training on treadmills for four weeks wearing a sandbag weighing 3% of the body weight on the affected side ankle, followed by wearing a sandbag weighing 5% of the body weight from the 5th week. The NLG performed similar training without sandbags. [Results] Both the IWLG and the NLG showed significant improvements in balance ability. The IWLG showed a larger decrease in the area and length of movement of the center of pressure in static standing positions after the experiment although the difference was not significant. [Conclusion] We recommend, utilizing the treadmill-based gait training using incremental weight loading on the affected side ankle as a clinical intervention for improving hemiplegic stroke patients’ balance ability.

Influence of lower extremity sensory function on locomotor adaptation following stroke: a review

Following stroke, people commonly demonstrate locomotor impairments including reduced walking speed and spatiotemporal asymmetry. Rehabilitation programs have been effective in increasing gait speed, but spatiotemporal asymmetry has been more resistant to change. The inability to modify gait patterns for improved symmetry may be related, in part, to impairments in lower extremity sensation. Assessment of lower extremity sensory impairments in people post stroke, including cutaneous and proprioceptive sensation, has been insufficiently studied. Conventional rehabilitation programs, including body weight-supported walking or robotic assistance, that modify sensory feedback intended to alter lower extremity movement patterns have shown limited success in improving gait symmetry. Rehabilitation programs that amplify specific gait asymmetries have demonstrated the potential to ultimately produce more symmetric gait, presumably by allowing individuals post stroke to more readily perceive their gait asymmetry. The effectiveness of such error augmentation paradigms, however, may be influenced by lower extremity sensation and the ability of the central nervous system to be aware of altered lower extremity movement. The purpose of this review is to critically examine the literature on lower extremity sensory function and its influence on gait adaptation in people post stroke.

Contributions to enhanced activity in rectus femoris in response to Lokomat-applied resistance

The application of resistance during the swing phase of locomotion is a viable approach to enhance activity in the rectus femoris (RF) in patients with neurological damage. Increased muscle activity is also accompanied by changes in joint angle and stride frequency, consequently influencing joint angular velocity, making it difficult to attribute neuromuscular changes in RF to resistance. Thus, the purpose of this study was to evaluate the effects of resistance on RF activity while constraining joint trajectories. Participants walked in three resistance conditions; 0 % (no resistance), 5 and 10 % of their maximum voluntary contraction (MVC). Visual and auditory biofeedback was provided to help participants maintain the same knee joint angle and stride frequency as during baseline walking. Lower limb joint trajectories and RF activity were recorded. Increasing the resistance, while keeping joint trajectories constant with biofeedback, independently enhanced swing phase RF activity. Therefore, the observed effects in RF are related to resistance, independent of any changes in joint angle. Considering resistance also affects stride frequency, a second experiment was conducted to evaluate the independent effects of resistance and stride frequency on RF activity. Participants walked in four combinations of resistance at 0 and 10 %MVC and natural and slow stride frequency conditions. We observed significant increases in RF activity with increased resistance and decreased stride frequency, confirming the independent contribution of resistance on RF activity as well as the independent effect of stride frequency. Resistance and stride frequency may be key parameters in gait rehabilitation strategies where either of these may be manipulated to enhance swing phase flexor muscle activity in order to maximize rehabilitation outcomes.

Effects of repeated walking in a perturbing environment: a 4-day locomotor learning study

Previous studies have shown that when subjects repeatedly walk in a perturbing environment, initial movement error becomes smaller, suggesting that retention of the adapted locomotor program occurred (learning). It has been proposed that the newly learned locomotor program may be stored separately from the baseline program. However, how locomotor performance evolves with repeated sessions of walking with the perturbation is not yet known. To address this question, 10 healthy subjects walked on a treadmill on 4 consecutive days. Each day, locomotor performance was measured using kinematics and surface electromyography (EMGs), before, during, and after exposure to a perturbation, produced by an elastic tubing that pulled the foot forward and up during swing, inducing a foot velocity error in the first strides. Initial movement error decreased significantly between days 1 and 2 and then remained stable. Associated changes in medial hamstring EMG activity stabilized only on day 3, however. Aftereffects were present after perturbation removal, suggesting that daily adaptation involved central command recalibration of the baseline program. Aftereffects gradually decreased across days but were still visible on day 4. Separation between the newly learned and baseline programs may take longer than suggested by the daily improvement in initial performance in the perturbing environment or may never be complete. These results therefore suggest that reaching optimal performance in a perturbing environment should not be used as the main indicator of a completed learning process, as central reorganization of the motor commands continues days after initial performance has stabilized.

Use of visual and proprioceptive feedback to improve gait speed and spatiotemporal symmetry following chronic stroke: a case series

BACKGROUND AND PURPOSE

Persistent deficits in gait speed and spatiotemporal symmetry are prevalent following stroke and can limit the achievement of community mobility goals. Rehabilitation can improve gait speed, but has shown limited ability to improve spatiotemporal symmetry. The incorporation of combined visual and proprioceptive feedback regarding spatiotemporal symmetry has the potential to be effective at improving gait.

CASE DESCRIPTION

A 60-year-old man (18 months poststroke) and a 53-year-old woman (21 months poststroke) each participated in gait training to improve gait speed and spatiotemporal symmetry. Each patient performed 18 sessions (6 weeks) of combined treadmill-based gait training followed by overground practice. To assist with relearning spatiotemporal symmetry, treadmill-based training for both patients was augmented with continuous, real-time visual and proprioceptive feedback from an immersive virtual environment and a dual belt treadmill, respectively.

OUTCOMES

Both patients improved gait speed (patient 1: 0.35 m/s improvement; patient 2: 0.26 m/s improvement) and spatiotemporal symmetry. Patient 1, who trained with step-length symmetry feedback, improved his step-length symmetry ratio, but not his stance-time symmetry ratio. Patient 2, who trained with stance-time symmetry feedback, improved her stance-time symmetry ratio. She had no step-length asymmetry before training.

DISCUSSION

Both patients made improvements in gait speed and spatiotemporal symmetry that exceeded those reported in the literature. Further work is needed to ascertain the role of combined visual and proprioceptive feedback for improving gait speed and spatiotemporal symmetry after chronic stroke.

Evaluation of biomechanical effects of four stimulation devices placed on the hind feet of trotting horses

OBJECTIVE

To compare effects of 4 types of stimulation devices attached to the hind feet on hoof flight, joint angles, and net joint powers of trotting horses.

ANIMALS

8 clinically normal horses.

PROCEDURES

Horses were evaluated under 5 conditions in random order: no stimulators, loose straps (10 g), lightweight tactile stimulators (55 g), limb weights (700 g), and limb weights with tactile stimulators (700 g). Reflective markers on the hind limbs were tracked during the swing phase of 6 trotting trials performed at consistent speed to determine peak hoof heights and flexion angles of the hip, stifle, tarsal, and metatarsophalangeal joints. Inverse dynamic analysis was used to calculate net joint energies. Comparisons among stimulators were made.

RESULTS

Peak hoof height was lowest for no stimulators (mean ± SD, 5.42 ± 1.38 cm) and loose straps (6.72 ± 2.19 cm), intermediate for tactile stimulators (14.13 ± 7.33 cm) and limb weights (16.86 ± 15.93 cm), and highest for limb weights plus tactile stimulators (24.35 ± 13.06 cm). Compared with no stimulators, net tarsal energy generation increased for tactile stimulators, limb weights, and limb weights plus tactile stimulators, but only the weighted conditions increased net energy generation across the hip joint.

CONCLUSIONS AND CLINICAL RELEVANCE

The type and weight of foot stimulators affected the magnitude of the kinematic and kinetic responses and the joints affected. These findings suggest that different types of foot stimulators are appropriate for rehabilitation of specific hind limb gait deficits, such as toe dragging and a short stride.

Movement therapy induced neural reorganization and motor recovery in stroke: a review

This paper is a review conducted to provide an overview of accumulated evidence on contemporary rehabilitation methods for stroke survivors. Loss of functional movement is a common consequence of stroke for which a wide range of interventions has been developed. Traditional therapeutic approaches have shown limited results for motor deficits as well as lack evidence for their effectiveness. Stroke rehabilitation is now based on the evidence of neuroplasticity, which is responsible for recovery following stroke. The neuroplastic changes in the structure and function of relevant brain areas are induced primarily by specific rehabilitation methods. The therapeutic method which induces neuroplastic changes, leads to greater motor and functional recovery than traditional methods. Further, the recovery is permanent in nature. During the last decade various novel stroke rehabilitative methods for motor recovery have been developed. This review focuses on the methods that have evidence of associated cortical level reorganization, namely task-specific training, constraint-induced movement therapy, robotic training, mental imaging, and virtual training. All of these methods utilize principles of motor learning. The findings from this review demonstrated convincing evidence both at the neural and functional level in response to such therapies. The main aim of the review was to determine the evidence for these methods and their application into clinical practice.

Walking: the first steps in cardiovascular disease prevention

PURPOSE OF REVIEW

Health professionals are presented with the challenge of prescribing physical activity that is likely to be sustained by the sedentary majority. Walking is eminently suited to physical activity prescription for inactive individuals as it is accessible to men and women of all ages and social groups and poses little risk of injury. This paper reviews recent evidence of the health benefits of walking and promotion of walking behavior.

RECENT FINDINGS

Large observational studies consistently show associations between walking and cardiovascular disease endpoints over long periods of follow-up. Intervention studies further support the health benefits of walking, showing improvements in clinical biomarkers and measures after shorter periods of follow-up. Walking appears to have cardiovascular disease-related health benefits in younger, middle-aged, and older men and women, in both healthy and patient populations. Pedometer-based, mobile phone-based, and computer-based programs are effective in increasing walking levels. Neighborhood and workplace amenities and programs may be important supports for walking behaviors.

SUMMARY

Walking has the potential to play a key role in the primary and secondary prevention of cardiovascular disease. Clinicians can prescribe walking to assist patients meet physical activity recommendations and help identify supports available to the patient.