Ambulation training of neurological patients on the treadmill with a new Walking Assistance and Rehabilitation Device (WARD)

Lower-body positive pressure diminishes surface blood flow reactivity during treadmill walking

Objective

The purpose of this study was to determine the effects of the lower-body positive pressure on surface blood flow during standing still and treadmill walking to explore cardiovascular safety for application to rehabilitation treatment. Thirteen healthy volunteers participated in the experiment and surface blood flows were measured in the forehead, thigh, calf, and the top of the foot during standing still and walking under various pressure conditions (0 kPa, 5 kPa, and 6.7 kPa).

Results

Lower-body positive pressure decreased the blood flow in the forehead and the thigh during walking (p < .05 for each), whereas an increasing trend in blood flow was observed during standing still (p < .05). Furthermore, in the forehead and thigh, the extent of blood flow increase at the onset of walking was found to decrease in accordance with the applied pressure (p < .01 for each). These findings suggest that during walking, lower-body positive pressure modulates the blood flow, which implies safeness of this novel apparatus for use during orthopedic rehabilitation treatment.

Comparison of neural activation and energy cost during treadmill walking with body weight unloading between frail and healthy older women

The aims of the study were to investigate whether body weight unloading (BWU) enables frail older women to walk on a treadmill without increasing energy and cardiac cost compared to normal gravity conditions and whether BWU affects lower extremity muscle activation levels. Oxygen uptake, heart rate (HR) and surface electromyography (EMG) of vastus medialis (VM) and biceps femoris (BF) of 10 frail older women (mean±SD; 78±3.6 years) and 10 healthy older women (78.5±4.2 years) were measured during various walking conditions overground and on a treadmill with BWU. Frail older women exercising at their self-selected comfortable walking speed on the treadmill at 0% BWU had a higher walking energy cost per unit of time (WECt) compared to overground walking at the same speed (255±46 vs 207±32 J kg(-1) min(-1), P<0.05), whereas healthy older women had similar responses in the two conditions (262±31 vs 260±39 J kg(-1) min(-1)). However, WECt of treadmill walking at self-selected fast walking speed with 40% BWU was not statistically different to overground walking at comfortable walking speed for frail (218±36 vs 207±31 J kg(-1) min(-1)) or healthy older women (265±65 vs 262±32 J kg(-1) min(-1)). EMG of the VM and BF muscles did not significantly change in either group during treadmill walking at any speeds up to 40% BWU (P>0.05). Frail older women could therefore be safely trained on a treadmill with 40% BWU thus achieving faster speeds without increasing energy and cardiac cost and without compromising lower extremity muscle activation levels.

Charcot-Marie-Tooth 1A patients with low level of impairment have a higher energy cost of walking than healthy individuals

The study aimed at quantifying the walking energy cost of a group of Charcot-Marie-Tooth 1A patients (CMT1A), with low severity of walking impairment, in comparison with healthy individuals. Oxygen uptake was measured in 8 patients (age-range 20-48 years; Barthel >90; Tinetti >20) and 8 healthy individuals, matched for age and gender, when walking on a circuit for 5-min at their self-selected speeds ("slow", "comfortable" and "fast"). Both comfortable and fast speeds were lower in patients than in the control group (0.92±0.16 vs 1.16±0.22 and 1.27±0.27 vs 1.61±0.22 m s⁻¹, respectively; P<0.05), whereas walking energy cost per unit of distance was higher in patients than in the control group (P<0.05) at both "comfortable" (2.27±0.35 vs 1.92±0.21 J kg⁻¹m⁻¹) and "fast" speed (3.05±0.35 vs 2.37±0.42 J kg⁻¹m⁻¹). CMT1A patients, therefore, choose to walk slower but with higher metabolic cost compared to healthy individuals, despite no clinically evident walking impairment, which is likely due to altered walking patterns.

Swim training initiated acutely after spinal cord injury is ineffective and induces extravasation in and around the epicenter

Activity-based rehabilitation is a promising strategy for improving functional recovery following spinal cord injury (SCI). While results from both clinical and animal studies have shown that a variety of approaches can be effective, debate still exists regarding the optimal post-injury period to apply rehabilitation. We recently demonstrated that rats with moderately severe thoracic contusive SCI can be re-trained to swim when training is initiated 2 weeks after injury and that swim training had no effect on the recovery of overground locomotion. We concluded that swim training is a task-specific model of post-SCI activity-based rehabilitation. In the present study, we ask if re-training initiated acutely is more or less effective than when initiated at 2 weeks post-injury. Using the Louisville Swim Scale, an 18-point swimming assessment, supplemented by kinematic assessment of hindlimb movement during swimming, we report that acute re-training is less effective than training initiated at 2 weeks. Using the bioluminescent protein luciferase as a blood-borne macromolecular marker, we also show a significant increase in extravasation in and around the site of SCI following only 8 min of swimming at 3 days post-injury. Taken together, these results suggest that acute re-training in a rat model of SCI may compromise rehabilitation efforts via mechanisms that may involve one or more secondary injury cascades, including acute spinal microvascular dysfunction.

Cardiorespiratory capacity after weight-supported treadmill training in patients with traumatic brain injury

BACKGROUND AND PURPOSE

The primary goal of body-weight-supported treadmill training (BWSTT) has been to improve the temporal and spatial characteristics of unsupported overground walking; however, little attention has been given to cardiorespiratory adaptations. The purpose of this case report is to describe the effects of BWSTT on cardiorespiratory fitness in 2 patients recovering from severe traumatic brain injury (TBI).

CASE DESCRIPTION

Both patients were involved in motor vehicle accidents and were studied after admission to a postacute residential treatment program. Patient 1 was a 25-year-old man (initial Glasgow Coma Scale [GCS] score=3) who began observation and treatment 3 months after the injury. Patient 2 was an 18-year-old woman (initial GCS=6) who began observation and treatment 1 year after the injury.

OUTCOMES

Each patient received 2 to 3 sessions of BWSTT per week. Aerobic capacity was measured while they ambulated on a treadmill without body-weight support before and after BWSTT. Both patients' submaximal and peak responses improved. For patient 1 and patient 2, total treadmill work performed increased 134% and 53%, respectively. Peak oxygen uptake increased 24% for patient 1 and 16% for patient 2. Estimated cardiac stroke volume (oxygen pulse) increased 32% and 26% for patient 1 and patient 2, respectively.

DISCUSSION

The observations made on these 2 patients suggest that BWSTT has the potential to favorably change cardiorespiratory capacity after TBI.

Speed training with body weight unloading improves walking energy cost and maximal speed in 75- to 85-year-old healthy women

This randomized controlled study was designed to prove the hypothesis that a novel approach to high-speed interval training, based on walking on a treadmill with the use of body weight unloading (BWU), would have improved energy cost and speed of overground walking in healthy older women. Participants were randomly assigned to either the exercise group (n = 11, 79.6 +/- 3.7 yr, mean +/- SD) or the nonintervention control group (n = 11, 77.6 +/- 2.3 yr). During the first 6 wk, the exercise group performed walking interval training on the treadmill with 40% BWU at the maximal walking speed corresponding to an intensity close to heart rate at ventilatory threshold (T(vent) walking speed). Each session consisted of four sets of 5 min of walking (three 1-min periods at T(vent) walking speed, with two 1-min intervals at comfortable walking speed in between each period at T(vent) walking speed) with 1-min interval between each set. Speed was increased session by session until the end of week 6. BWU was then progressively reduced to 10% during the last 6 wk of intervention. After 12 wk, the walking energy cost per unit of distance at all self-selected overground walking speeds (slow, comfortable, and fast) was significantly reduced in the range from 18 to 21%. The exercise group showed a 13% increase in maximal walking speed and a 67% increase in mechanical power output at T(vent) after the training program. The novel "overspeed" training approach has been demonstrated to be effective in improving energy cost and speed of overground walking in healthy older women.

Physiological costs and temporo-spatial parameters of walking on a treadmill vary with body weight unloading and speed in both healthy young and older women

Walking on a treadmill with Body Weight Unloading (BWU), which has been successfully used on patients with neurological conditions, may also be used as a training tool to increase walking speed in healthy individuals. We hypothesised that BWU enables individuals to walk at a faster speed on a treadmill than they would do in normal gravity conditions without increasing their effort and with an increase in both stride length (SL) and stride frequency (SF). Oxygen uptake, heart rate (HR), SL and SF of six older women (mean +/- SD; 70 +/- 4 years) and six young women (26 +/- 3 years) were measured during treadmill walking at three self-selected speeds (comfortable, slow and fast) and three different percentages of BWU (0, 20 and 40%). No significant differences were found between the groups in any self-selected walking speeds and any of the other variables. The combined data of the two groups showed that walking energy cost per unit of time (WECt) and HR at fast speed with 40% of BWU (258 +/- 60 J kg(-1) min(-1) and 95 +/- 15 beats min(-1), respectively) were similar to those measured at comfortable speed with no BWU (273 +/- 47 J kg(-1) min(-1) and 101 +/- 16 beats min(-1), respectively). Also SL and SF increased significantly with speed (P < 0.017) at any given percentage of BWU. The results suggest that 40% of BWU enables both young and older women to walk at a faster speed on a treadmill without increasing their effort and with an increase in both SL and SF.

Voluntary Wheel Running Improves Recovery from a Moderate Spinal Cord Injury

Recently, locomotor training has been shown to improve overground locomotion in patients with spinal cord injury (SCI). This has triggered renewed interest in the role of exercise in rehabilitation after SCI. However, there are no mouse models for voluntary exercise and recovery of function following SCI. Here, we report voluntary wheel running improves recovery from a SCI in mice. C57Bl/10 female mice received a 60-kdyne T9 contusion injury with an IH impactor after 3 weeks of voluntary wheel running or 3 weeks of standard single housing conditions. Following a 7-day recovery period, running mice were returned to their running wheels. Weekly open-field behavior measured locomotor recovery using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale and the Basso Mouse Scale (BMS) locomotor rating scale, a scale recently developed specifically for mice. Initial experiments using standard rung wheels show that wheel running impaired recovery, but subsequent experiments using a modified flat-surface wheel show improved recovery with exercise. By 14 days post SCI, the modified flat-surface running group had significantly higher BBB and BMS scores than the sedentary group. A repeated measures ANOVA shows locomotor recovery of modified flat-surface running mice was significantly improved compared to sedentary animals (p < 0.05). Locomotor assessment using a ladder beam task also shows a significant improvement in the modified flat-surface runners (p < 0.05). Finally, fibronectin staining shows no significant difference in lesion size between the two groups. These data represent the first mouse model showing voluntary exercise improves recovery after SCI.

Determinants of sit-to-stand capability in the motor impaired elderly

Among the healthy elderly, sit-to-stand (STS) movement largely depends on: (a) trunk bending momentum, (b) centre of gravity (CG) position before the body rises and (c) lower limb extensor muscle strength. Because determining whether (c) improvement would affect STS capability in the motor impaired elderly (MIE) has been recommended, we studied the relative importance of (a), (b) and (c) in determining a successful fast STS movement comparing the healthy elderly with MIE with orthopaedic disorders studied before and after a rehabilitation program. Force platform was used to measure body's posture and kinematics during a STS test and therefore to assess (a), (b) and maximum vertical velocity (VVpeak), assumed as outcome measurement. Knee extensor maximal isometric voluntary contraction normalized by body mass (nMVC) was an indicator of (c). A multiple regression model was built to predict VVpeak from the three determinants of STS movement. In both groups, the model significantly determined VVpeak, with (a) and (c) being significant predictors of VVpeak and (a) being the major predictor. Rehabilitation was effective in improving nMVC. This process resulted in a change of the relative importance of (a) and (c), strength becoming the major predictor of VVpeak. In conclusion the present study demonstrates that a rehabilitative intervention aimed at increasing strength is effective in improving STS capability in MIE.

Treadmill training with partial body weight support after stroke

Treadmill therapy with partial BWS is a promising new approach to improve gait ability after stroke. This task-specific approach enables nonambulatory patients the repetitive practice of complex gait cycles instead of single-limb gait-preparatory maneuvers. Patients walk more symmetrically with less spasticity and better cardiovascular efficiency on the treadmill than with floor walking. Several controlled, clinical studies have shown the potential of treadmill training as a therapeutic intervention for nonambulatory patients with chronic stroke-related hemiplegia. Furthermore, controlled trials in acute stroke survivors have shown that treadmill training is as effective as other physiotherapy approaches that stress the repetitive practice of gait. Controlled multicenter trials comparing locomotor training with conventional therapy will be forthcoming. An electromechanical gait trainer that relieves the strenuous effort of the therapists and provides control of the trunk in a phase-dependent manner is a new technical alternative for gait training in severely impaired stroke patients.

Using robotics to teach the spinal cord to walk

We have developed a robotic device (e.g. the rat stepper) that can be used to impose programmed forces on the hindlimbs of rats during stepping. In the present paper we describe initial experiments using this robotic device to determine the feasibility of robotically assisted locomotor training in complete spinally transected adult rats. The present results show that using the robots to increase the amount of load during stance by applying a downward force on the ankle improved lift during swing. The trajectory pattern during swing was also improved when the robot arms were programmed to move the ankle in a path that approximated the normal swing trajectory. These results suggest that critical elements for successful training of hindlimb stepping in spinal cord injured rats can be implemented rigorously and evaluated using the rat stepper.

Gait analysis on the treadmill - monitoring exercise in the treatment of paraplegia

STUDY DESIGN

A prospective study was performed to evaluate the gait training of seven consecutive spinal cord injured patients and 10 controls on a treadmill using instrumented gait analysis and video documentation.

OBJECTIVES

To determine whether it is possible to maintain gait motion within physiological limits during treadmill training.

SETTING

Primary and secondary care unit for spinal cord injury, Heidelberg, Germany.

METHODS

Treadmill training was instituted as early as possible. Gait analysis was performed when the patients were stable enough to walk without manual aid from therapists and enough endurance to allow measurements. A control group of healthy volunteers were examined as well. Video documentation and a camera system using passive markers were employed.

RESULTS

Treadmill training started with weight reduction of 25% of bodyweight (18 (0-35) kg), maximum walking speed 0.28 (0.15-0.7) m/s and maximum walking duration 4.7 (3-7) min. At the end of the training, weight reduction decreased to 9.3 (0-20) kg, maximum walking speed increased to 0.67 (0.23-1.1) ms with a maximum walking duration of 11 (8-15) min. 3-D motion analysis of hip, knee and ankle demonstrated joint excursions almost entirely within the limits of normal gait. Exceptions were due to fixed contractures.

CONCLUSIONS

Our data suggests that it is possible to perform early gait training on a treadmill with no supportive orthoses within the physiologic range of joint motion. The risk for repetitive stress injuries or other negative effects is low.

Influence of walking speed on lower limb muscle activity and energy consumption during treadmill walking of hemiparetic patients

OBJECTIVE

To identify the relationship between treadmill speed and energy consumption and lower limb muscle activity in ambulatory hemiparetic patients.

DESIGN

Experimental cohort.

SETTING

Inpatient rehabilitation clinic.

PARTICIPANTS

Twenty-four ambulatory hemiparetic subjects.

INTERVENTION

Subjects walked harness-secured on the treadmill with no body-weight support at self-reported (V SAS), slow (V SAS - 25%), and fast (V SAS + 25%) speed.

MAIN OUTCOME MEASURES

Assessment of basic, limb-dependent cycle parameters, lower limb muscle activity, and energy consumption.

RESULTS

Cadence (r = .75), stride length (r = .78), relative double-support duration (r = .31), mean muscle activity of the paretic tibialis anterior (r = .12), gastrocnemius (r = .37), vastus lateralis (r =.19), rectus femoris (r = .31), and biceps femoris (r = .45) muscles, as well as heart rate (r = .54), correlated positively with treadmill speed. Mean maximum heart rate was 131 beats/min. Energy (r = -.67) and cardiac cost (r = -.55) correlated negatively with gait speed (ie, patients walked more efficiently at faster velocities). The qualitative muscle activation pattern analysis revealed earlier (more normal) onset of activation of gastrocnemius, vastus lateralis, biceps femoris, and gluteus medius.

CONCLUSIONS

Patients should try to walk fast on the treadmill, thereby facilitating relevant weight-bearing muscles and improving gait efficiency.

Body weight-supported treadmill training after stroke

Gait rehabilitation is a major aspect of neurologic rehabilitation. This review focuses on locomotor therapy by treadmill stimulation with partial body weight support (BWS), which has become a very promising treatment concept over the past few years. It enables severely affected patients to follow modern aspects of motor learning, favoring a task-specific approach. Initially two therapists assist the movement, placing the paretic limbs and controlling the trunk movements. As compared with overground walking, patients walked more symmetrically, less spastically, and more efficiently on the treadmill with BWS. Several clinical controlled studies have shown its potential in patients after stroke, who regained walking ability faster in the acute or in the chronic stage. Controlled multicenter trials comparing locomotor and conventional therapy will be the next step. Also, the use of BWS during overground walking could be incorporated into the locomotor treatment program of less affected stroke patients. An electromechanical gait trainer relieving the strenuous effort of the therapists and controlling the trunk in a phase-dependent manner is a new technical alternative for severe stroke patients.