Selective tibial neurotomy in the treatment of spastic equinovarus foot: a 2-year follow-up of three cases

OBJECTIVE: To objectively assess the decrease in spasticity and the improvement in gait after tibial nerve neurotomy performed to treat spastic equinovarus foot. DESIGN: Before-after trial with a 2-yr follow-up. Three hemiplegic patients with spastic equinovarus foot were treated with a selective peripheral neurotomy of the tibial motor nerve branches (soleus, lateral and medial gastrocnemius and tibialis posterior nerves). Evaluation included clinical assessment of spasticity (Ashworth scale), maximal Hoffmann reflex (H(max))/compound muscle action potential (M(max)) ratio measurement, gait analysis, and muscle stiffness evaluation performed before and 2 mos, 1 yr, and 2 yrs after the neurotomy. RESULTS: Spasticity, muscle stiffness, and H(max)/M(max) ratio decreased after neurotomy. The kinematic (ankle dorsal flexion and knee recurvatum) and kinetic variables (maximum ankle muscle moment and external work) of the gait were permanently improved after neurotomy. Interestingly, kinetic variables seemed to gradually improve with time after the neurotomy. CONCLUSION: Tibial neurotomy is an effective and durable treatment for spastic equinovarus foot.     

Incidence of Gait Abnormalities After Traumatic Brain Injury

Williams G, Morris ME, Schache A, McCrory PR. Incidence of gait abnormalities after traumatic brain injury.

Objective

To identify the most common gait abnormalities presenting after traumatic brain injury (TBI) and quantify their incidence rate.

Design

Case series.

Setting

Biomechanics laboratory.

Participants

A convenience sample of 41 people with TBI receiving therapy for gait abnormalities, and a sample of 25 healthy controls.

Intervention

Three-dimensional gait analysis.

Main Outcome Measures

Spatiotemporal, kinematic, and kinetic data at a self-selected walking speed.

Results

People with TBI walked with a significantly slower speed than matched healthy controls. There was a significant difference between groups for cadence, step length, stance time on the affected leg, double support phase, and width of base of support. The most frequently observed biomechanical abnormality was excessive knee flexion at initial foot contact. Other significant gait abnormalities were increased trunk anterior/posterior amplitude of movement, increased anterior pelvic tilt, increased peak pelvic obliquity, reduced peak knee flexion at toe-off, and increased lateral center of mass displacement. Ankle equinovarus at foot-contact occurred infrequently.

Conclusions

People with TBI were found to have multijoint gait abnormalities. Many of these abnormalities have not been previously reported in this population.     

Functional Assessment of Lower Extremities in Hereditary Spastic Paraplegia

Braschinsky M, Parts K, Maamägi H, Gross-Paju K, Haldre S. Functional assessment of lower extremities in hereditary spastic paraplegia.

Objectives

To characterize the spasticity and range of motion (ROM) in patients with hereditary spastic paraplegia (HSP) and to correlate these parameters with walking speed.

Design

An observational population-based cohort study.

Setting

Patient data were acquired from a population-based epidemiologic study performed earlier in Estonia.

Participants

Persons (N=46) (mean age, 50.1y) with clinically confirmed HSP diagnosis (mean duration, 20.9y) participated in the study.

Interventions

Active and passive ROMs were measured with a plastic 360° goniometer. Spasticity was evaluated by using the modified Ashworth scale (MAS). The time it took a patient to walk 10m was recorded.

Main Outcome Measures

Measurements included testing of active and passive ROM as a marker for mobility, the MAS for spasticity, and time to complete a 10-m walk.

Results

A higher degree of spasticity in hip muscles was associated with lower values of active ROM and slower walking. Walking speed was negatively correlated to disease duration and participant age.

Conclusions

The present study provides analysis of the contributions of spasticity and ROM to walking speed in HSP, both factors negatively influence gait in persons with HSP.     

Effects of Combining Electric Stimulation With Active Ankle Dorsiflexion While Standing on a Rocker Board: A Pilot Study for Subjects With Spastic Foot After Stroke

Cheng J-S, Yang Y-R, Cheng S-J, Lin P-Y, Wang R-Y. Effects of combining electric stimulation with active ankle dorsiflexion while standing on a rocker board: a pilot study for subjects with spastic foot after stroke.

Objective

To investigate the therapeutic effects of combining electric stimulation (ES) with active ankle dorsiflexion while standing on a rocker board in subjects with plantarflexor spasticity after stroke.

Design

Randomized controlled trial.

Setting

A rehabilitation medical center.

Participants

Subjects (N=15) with spastic foot after stroke.

Interventions

Subjects were randomly assigned to an experimental or a control group. The experimental group received ES of ankle dorsiflexors in concert with a motor training paradigm that required the subject to dorsiflex the ankles in response to a cue while standing on a rocker board. After 30 minutes of this exercise, subjects received ambulation training focusing on ankle control for 15 minutes. The control group received general range of motion and strength exercises for 30 minutes, followed by 15 minutes of ambulation training focusing on ankle control. Sessions occurred 3 times a week for 4 weeks.

Main Outcome Measures

Dynamic spasticity of plantarflexors, dorsiflexor muscle strength, balance performance, gait kinematics, and functional gait performance as assessed by the Emory Functional Ambulation Profile (EFAP) were used as outcome measurements.

Results

The experimental group demonstrated a greater decrease in dynamic ankle spasticity at a comfortable gait speed (P=.049), a greater improvement in spatial gait symmetry (P=.015), and a greater improvement in functional gait ability as indicated by the EFAP (P=.015) than the control group.

Conclusions

Our results suggest that repeated ES with volitional ankle movements can decrease dynamic ankle spasticity in subjects with stroke. Furthermore, such improvement parallels better gait symmetry and functional gait performance.     

Relationship Between Age and Spasticity in Children With Diplegic Cerebral Palsy

Pierce SR, Prosser LA, Lauer RT. Relationship between age and spasticity in children with diplegic cerebral palsy.

Objective

To examine the relationship between passive torque, reflex activity, co-contraction, and age during the assessment of spasticity of knee flexors and extensors in children with spastic diplegic cerebral palsy (CP).

Design

Retrospective.

Setting

Pediatric orthopedic hospital.

Participants

Children (N=36) with spastic diplegic CP.

Interventions

Not applicable.

Main Outcome Measures

Spasticity of the knee flexors and knee extensors (as measured by peak passive torque, mean passive torque, reflex activity of the medial hamstrings, reflex activity of vastus lateralis, and co-contraction) was assessed during passive movements completed using an isokinetic dynamometer with concurrent electromyography.

Results

A significant positive relationship was found between age and mean knee flexor passive torque (P<.05), while a significant negative relationship was found between age and mean percentage of the range of motion with co-contraction (P<.05).

Conclusions

Our results suggest that passive stiffness may play a larger role in spasticity than reflex activity as children with spastic diplegic CP age. Additional research is needed to determine whether subject age could influence the effectiveness of interventions, such as serial casting or botulinum toxin, for spasticity in children with spastic diplegic CP.     

Evaluation of velocity-dependent performance of the spastic elbow during voluntary movements

Song R, Tong KY, Hu XL. Evaluation of velocity-dependent performance of the spastic elbow during voluntary movements.

Objective

To evaluate quantitatively, using a voluntary elbow-tracking experiment, the performance at different angular velocities of unaffected elbow compared with spastic elbow after stroke.

Design

Poststroke subjects were recruited to perform voluntary movements of elbow flexion and extension by following sinusoidal trajectories from 30° to 90° at peak angular velocities of 15.7°, 31.4°, 47.1°, 62.8°, 78.5°, and 94.2°/s in a horizontal plane. The actual elbow angle and the target position were displayed as real-time visual feedback.

Setting

Rehabilitation center research laboratory.

Participants

Nine hemiplegic chronic stroke patients.

Interventions

Not applicable.

Main Outcome Measures

Root mean square error (RMSE) between actual elbow angle and target angle, root mean square jerk (RMSJ), and Modified Ashworth Scale (MAS). Jerk is the rate of change of acceleration, which is the third derivative of the actual angle. A smooth motion has less jerk.

Results

The RMSE and RMSJ had a good reliability. The RMSE and RMSJ increased in both affected and unaffected arms with increasing tracking velocity. The RMSE and RMSJ of the unaffected arms were significantly lower than those of the affected arms at all the velocities. There was significant correlation between the RMSJ and MAS at the peak velocities of 15.7°, 31.4°, 47.1°, 62.8°, and 94.2°/s (correlation coefficient range, .67−.83).

Conclusions

The parameters reflected motion quality, which has potential for use in quantitatively evaluating the deficiencies of sensorimotor control of spastic elbow in persons after stroke during voluntary movements.     

A pilot study to investigate the combined use of Botulinum toxin type-a and ankle foot orthosis for the treatment of spastic foot in chronic hemiplegic patients

Background

Botulinum toxin is commonly used to treat spastic equinus foot. This treatment seems to improve gait in hemiplegic patients when used alone or combined with an ankle-foot orthosis. However, the nature and effects of this improvement have until now rarely been studied. The aim of this study was to quantify the impact of a Botulinum toxin injection in the triceps surae of hemiplegic patients with equinus foot, used either alone or in combination with an ankle-foot orthosis, on the kinematics and dynamics of the paretic lower limb, and to determine the advantage of combining an ankle-foot orthosis with this pharmacological treatment.

Methods

Patients were assessed using gait analysis to measure spatio-temporal, kinematic and dynamic parameters of the gait cycle before Botulinum toxin injection and then 3 and 6 weeks after injection. Eight chronic hemiplegics following central nervous system lesion were included.

Findings

Botulinum toxin injection led to an increase in velocity, peak ankle dorsiflexion during stance phase, and peak knee flexion during swing phase. It also resulted in an increased peak plantarflexion moment. Use of ankle-foot orthosis led to a specific increase in peak ankle dorsiflexion during swing phase and also increased peak plantarflexion moment.

Interpretation

The results indicate that combined Botulinum toxin injection of the triceps surae and wearing an ankle-foot orthosis is more effective than the use of Botulinum toxin only. Use of an ankle-foot orthosis increases ankle dorsiflexion during the swing phase and does not reduce the benefits gained by the use of Botulinum toxin in stance phase.     

The effects of hip and ankle stretching on gait function of older people

Christiansen CL. The effects of hip and ankle stretching on gait function of older people.

Objective

To examine effects of hip and ankle stretching on gait function of older people.

Design

Randomized controlled trial.

Setting

Flexibility training was performed in participants' homes. Assessments were performed in a biomechanics laboratory.

Participants

Forty healthy volunteers (mean age ± SD, 72.1±4.7y) randomized to 2 groups: intervention (n=20) and control (n=20).

Intervention

Intervention participants performed an 8-week stretching program, and control group participants maintained activity level for 8 weeks. One investigator made weekly visits to instruct and monitor participants.

Main Outcome Measures

Primary outcome measures were passive joint motion for hip extension and ankle dorsiflexion and freely chosen gait speed. Secondary outcome measures were gait parameters during freely chosen gait speed and set gait speed walking (stride length, joint displacement).

Results

Compared with the control group, the intervention group had increased combined hip and knee motion (P=.023), ankle motion (P=.020), and freely chosen gait speed (P=.016). The intervention group showed statistically nonsignificant trends of increased stride length at freely chosen gait speed and set gait speed.

Conclusions

Findings suggest joint motion is a modifiable impairment that is effectively targeted with flexibility training for older people. Participants in the intervention group had improvements in joint motion as well as increased freely chosen gait speed. Mechanisms responsible for changes in freely chosen gait speed warrant further investigation.     

Gait Analysis in Patients With Parkinson's Disease Off Dopaminergic Therapy

Švehlík M, Zwick EB, Steinwender G, Linhart WE, Schwingenschuh P, Katschnig P, Ott E, Enzinger C. Gait analysis in patients with Parkinson's disease off dopaminergic therapy.

Objective

To compare time-distance, kinematic, and kinetic gait parameters in patients with idiopathic Parkinson's disease (PD) off dopaminergic therapy with a group of healthy control subjects.

Design

A group-comparison study.

Setting

Gait analysis laboratory.

Participants

Patients with PD (n=20) and healthy age-matched controls (n=20).

Interventions

Not applicable.

Main Outcome Measures

Time-distance, kinematic, and kinetic gait variables.

Results

PD patients walked slower with shorter stride-length, comparable cadence, and longer double support times. Kinematics showed a reduction of the range of motion in the hip, knee, and ankle joints. Maximum hip extension and the ankle plantar flexion were significantly reduced. Kinetic gait parameters showed reduced push-off ankle power and lift-off hip power generation. Strong correlations between these important body advancement mechanisms and the walking velocity were observed.

Conclusions

In addition to previously described dysfunctional kinematics, abnormal kinetic parameters play an important role in the characterization of gait in PD patients off therapy. Hence, these parameters could be used to document treatment effects of parkinsonian gait disorders.     

Physical Function in Hip Osteoarthritis: Relationship to Isometric Knee Extensor Steadiness

Pua Y-H, Clark RA, Bryant AL. Physical function in hip osteoarthritis: relationship to isometric knee extensor steadiness.

Objective

To evaluate, in a community hip osteoarthritis sample, the cross-sectional associations of isometric strength and steadiness of the knee extensors and their interaction with physical performance measures of physical function.

Design

Cross-sectional.

Setting

Human movement laboratory of a university.

Participants

Sixty-seven adults (27 men and 40 women; age, 61±10y) with radiographically confirmed symptomatic hip osteoarthritis.

Interventions

Not applicable.

Main Outcome Measures

Participants performed isometric knee extensor steadiness and strength testing on a dynamometer. Physical function was assessed by using the habitual timed walk test and the self- and fast-paced stair-climbing tests.

Results

In the hierarchical regression models, although there were clear main effects of knee extensor steadiness on fast-paced stair performance, greater knee steadiness predictively associated with faster stair-climbing performance particularly in individuals with high knee extensor strength. In contrast, knee extensor steadiness was not related to gait speed regardless of knee extensor strength levels.

Conclusions

In patients with hip OA, knee extensor steadiness was positively associated with stair-climbing performance, particularly in those with high levels of knee extensor strength. These findings are of importance in developing intervention strategies, but they call for further study.     

Physical Function, Gait, and Dynamic Balance of Transfemoral Amputees Using Two Mechanical Passive Prosthetic Knee Devices

Lythgo N, Marmaras B, Connor H. Physical function, gait, and dynamic balance of transfemoral amputees using two mechanical passive prosthetic knee devices.

Objective

To investigate the effect of the 3R90 and 3R92 (Otto Bock Healthcare) mechanical passive prosthetic knee devices on the physical function, gait, and dynamic balance (sudden stop and turn) of transfemoral amputees.

Design

Intervention study with crossover design.

Setting

University research center.

Participants

Men (N=5; mean age ± SD, 58.8±11.9y) with unilateral transfemoral amputation.

Intervention

Prosthetic knee joints (N=2; 3R90 and 3R92). Acclimatization ranged from 14 to 47 days (25.5±9.3d).

Main Outcome Measures

Physical function, gait, dynamic balance.

Results

The Timed Up and Go Test, 6-Minute Walk Test, and Four Square Step Test measures improved with the 3R92. Total scores on the Prosthesis Evaluation Questionnaire were similar for the 3R92 (82.0±6.3) and the participant's own or original device (83.9±4.8). These devices were rated higher than the 3R90 (65.5±16.8). Compared with the original device, gait velocity was significantly slower (5cm/s; P=.017) with the 3R92, but was unchanged for the 3R90. This difference was not considered clinically significant because the effect size was small (0.2). No other significant gait differences were found. Large temporal gait asymmetries observed with the original device remained with the 3R90 and 3R92 (step, ≈20%; single support, ≈30%; stance, ≈19%). Although no significant differences were found for the sudden-turn or sudden-stop tasks, the sudden-turn group success rates were highest with the original devices.

Conclusions

Gait and symmetry measures were unchanged. Gait speed was slower with the 3R92, but this was not considered to be clinically significant. Sudden-turn success rates generally were higher with the original devices. A crossover stepping movement was more difficult to implement than a side-stepping movement during sudden turns.     

Locomotor treadmill training with partial body-weight support before overground gait in adults with acute stroke: a pilot study

McCain KJ, Pollo FE, Baum BS, Coleman SC, Baker S, Smith PS. Locomotor treadmill training with partial body-weight support before overground gait in adults with acute stroke: a pilot study.

Objective

To investigate the impact of locomotor treadmill training with partial body-weight support (BWS) before the initiation of overground gait for adults less than 6 weeks poststroke.

Design

Parallel group, posttest only.

Setting

Inpatient rehabilitation center.

Participants

Adults after first stroke admitted to an inpatient rehabilitation unit: treadmill group (n=7) and comparison group (n=7).

Interventions

Locomotor treadmill training with partial BWS or traditional gait training methods.

Main Outcome Measures

Gait kinematics, symmetry, velocity, and endurance at least 6 months postinsult.

Results

Data from 3-dimensional gait analysis and 6-minute walk test (6MWT) supported improved gait for adults postacute stroke who practiced gait on a treadmill before walking over ground. Gait analysis showed increased knee flexion during swing and absence of knee hyperextension in stance for the treadmill group. In addition, more normal ankle kinematics at initial contact and terminal stance were observed in the treadmill group. Improved gait symmetry in the treadmill group was confirmed by measures of single support time, hip flexion at initial contact, maximum knee flexion, and maximum knee extension during stance. The treadmill group also walked further and faster in the 6MWT than the comparison group.

Conclusions

Application of locomotor treadmill training with partial BWS before overground gait training may be more effective in establishing symmetric and efficient gait in adults postacute stroke than traditional gait training methods in acute rehabilitation.     

Neuroprosthetic Effect of Peroneal Nerve Stimulation in Multiple Sclerosis: A Preliminary Study

Sheffler LR, Hennessey MT, Knutson JS, Chae J. Neuroprosthetic effect of peroneal nerve stimulation in multiple sclerosis: a preliminary study.

Objective

To determine the neuroprosthetic effect of a peroneal nerve stimulator on tasks of functional ambulation in multiple sclerosis (MS).

Design

A single point-in-time assessment of functional ambulation tasks under the conditions of no device and peroneal nerve stimulator.

Setting

Outpatient academic medical center.

Participants

Participants (N=11) with diagnosis of MS (>6mo), dorsiflexion weakness, and prior usage of an ankle-foot orthosis.

Intervention

Surface peroneal nerve stimulator for ambulation.

Main Outcome Measures

Timed 25-foot Walk portion of the MS Functional Composite; Floor, Carpet, Up and Go, Obstacle, and Stair components of the Modified Emory Functional Ambulation Profile.

Results

Peroneal nerve stimulator-Stair performance was significantly enhanced (P=.05) versus no device, and statistical significance was approached for peroneal nerve stimulator-Obstacles (P=.09) versus no device. There were no significant differences between peroneal nerve stimulator and no device conditions in the remaining outcome measures.

Conclusions

The neuroprosthetic effect of the peroneal nerve stimulator is modest relative to no device in the performance of specific functional tasks of ambulation in MS gait. A longitudinal, controlled trial is needed to show effectiveness.     

A method to measure the accuracy of loads in knee-ankle-foot orthoses using conventional gait analysis, applied to persons with poliomyelitis

Andrysek J, Redekop S, Matsui NC, Kooy J, Hubbard S. A method to measure the accuracy of loads in knee-ankle-foot orthoses using conventional gait analysis, applied to persons with poliomyelitis.

Objectives

To determine (1) the forces and moments passing through knee-ankle-foot orthoses (KAFOs) during walking and (2) the accuracy with which these loads can be measured using conventional gait analysis techniques.

Design

Comparative case series.

Setting

Rehabilitation facility with human movement laboratory (gait lab).

Participants

Four patients with poliomyelitis wearing KAFOs.

Interventions

KAFOs were instrumented with a load cell, and walking data were concurrently collected using conventional gait analysis.

Main Outcome Measures

Load measurements and gait parameters.

Results

Predominant orthotic loads (knee joint forces and moments) were composed of knee flexion moments and axial compression forces. With conventional gait analysis, peak knee joint moments were substantially underestimated compared with those directly measured using the load cell. Defining the knee axis anatomically versus at the orthotic axis, tracking it dynamically, and compensating for each patient's corrected knee flexion contracture resulted in considerable improvements in the gait lab estimates of knee joint moments.

Conclusions

A practical method that directly measures moments and forces in conventional KAFOs has been applied to show that conventional gait analysis techniques substantially underestimate knee joint moments in the KAFOs of persons with poliomyelitis. Underestimation of orthotic loads could result in underdesigned orthotic components and ultimately higher incidence of component failure in clinical applications.     

Does treadmill exercise improve performance of cognitive or upper-extremity tasks in people with chronic stroke? A randomized cross-over trial

Ploughman M, McCarthy J, Bossé M, Sullivan HJ, Corbett D. Does treadmill exercise improve performance of cognitive or upper-extremity tasks in people with chronic stroke? A randomized cross-over trial.

Objective

To determine whether acute exercise, using a body-weight-supported treadmill, improves performance on subsequent cognitive tests or an upper-extremity task in people with stroke.

Design

The study was a within-subject, cross-over design in which 21 subjects received, randomly, 2 different testing sequences separated by an interval of 7 to 10 days.

Setting

Outpatient department of a rehabilitation hospital.

Participants

Of 72 potential participants in the convenience sample, 21 people with chronic stroke completed the study. They were 0.5 to 5 years after only 1 documented stroke, were able to walk with or without a cane, were able to grasp with the affected hand, and scored more than 24 on the Mini-Mental State Examination.

Interventions

One session of body-weight-supported treadmill walking for 20 minutes at 70% of estimated heart rate reserve or level 13 on the Borg rating of perceived exertion scale. The control condition consisted of a 20-minute review of a home exercise program with a physiotherapist.

Main Outcome Measures

Cognitive tests included Trail Making Tests Parts A and B, Symbol Digit Substitution Test, and Paced Auditory Serial Addition Test. The Action Research Arm Test (ARAT) measured hemiplegic upper-extremity motor skill.

Results

Treadmill exercise improved movement of the hemiplegic upper extremity (P=.04) but not cognitive performance. The improvement in the ARAT occurred without a change in strength (measured by grip strength) and was negatively correlated with maximum treadmill speed (R²=.20; P=.04).

Conclusions

These findings suggest that acute treadmill exercise improves subsequent skilled movement of the hemiplegic upper extremity that seems unrelated to attention, visuomotor processing, or strength. The etiology and duration of this enhancing effect are worth further study. The existence of an exercise-cognition relationship in people with stroke is an intriguing area of future research.     

Influence of Task on Interlimb Coordination in Adults With Cerebral Palsy

Langan J, Doyle ST, Hurvitz EA, Brown SH. Influence of task on interlimb coordination in adults with cerebral palsy.

Objective

To examine movement time and kinematic properties of unilateral and bilateral reaching movements in adults with cerebral palsy (CP), focusing on how different types of bilateral movements, simultaneous or sequential, may influence interlimb coordination.

Design

Quantitative study using between-group repeated-measures analyses.

Setting

Motor control laboratory at a research university.

Participants

Adults with hemiplegic CP (n=11; mean age ± SD, 33±10y; 4 men) and age-matched controls (mean age ± SD, 32±9y; 4 men).

Interventions

Not applicable.

Main Outcome Measures

Movement time (MT), maximum deviation from a straight trajectory to the target, and peak speed.

Results

Although adults with hemiplegic CP showed strong unilateral deficits, bilateral simultaneous reaching movements were temporally and spatially coupled. Movement of the less affected arm slowed to match the movement of the more affected arm. In contrast, bilateral sequential movements improved MTs of the less affected and more affected arms.

Conclusions

Bilateral sequential movements were conducive to faster MT compared with unilateral or bilateral simultaneous movements. Training that includes bilateral sequential movements may be beneficial to adults with hemiplegic CP. Upper-limb movements are coordinated in a variety of ways to perform routine bilateral tasks. Some bilateral tasks, such as stacking boxes, require more symmetric movements of the upper limbs. Other bilateral tasks, such as opening the refrigerator with 1 hand while placing an item on the shelf with the other hand, emphasize coordinated sequential action between upper limbs. Despite the prevalence of integrative upper-limb use, the control of different forms of bilateral movement is not well understood. A more comprehensive knowledge of upper-limb bilateral movements may hold important implications for developing more effective upper-limb movement therapies.     

Metabolic and Mechanical Energy Costs of Reducing Vertical Center of Mass Movement During Gait

Gordon KE, Ferris DP, Kuo AD. Metabolic and mechanical energy costs of reducing vertical center of mass movement during gait.

Objectives

To test the hypothesis that reducing vertical center of mass (COM) displacement will lower the metabolic cost of human walking. To examine changes in joint work associated with increasing and decreasing vertical COM movement during gait.

Design

Randomized repeated measures.

Setting

Human Neuromechanics Laboratory, University of Michigan.

Participants

Able-bodied subjects (N=10).

Interventions

Subjects walked at 1.2m/s on a treadmill and overground. Subjects manipulated vertical COM displacement either by adjusting stride length or by using visual feedback to reduce COM movement.

Main Outcome Measures

We measured kinematic and kinetic data to calculate vertical and lateral COM displacements, joint torques, and work. In addition, we collected oxygen consumption to calculated metabolic power.

Results

Increasing and decreasing vertical COM displacement beyond subjects' preferred range resulted in increases in the metabolic cost of walking. When vertical COM displacement was reduced, corresponding increases in positive ankle and hip work and negative knee work were observed.

Conclusions

Humans are capable of walking in a manner that will reduce COM displacement from normal. Decreasing vertical COM movement results in increases in metabolic energy costs because of greater mechanical work performed at the hip, knee, and ankle joints. Thus, reducing vertical COM movement is not a successful strategy for improving either metabolic or mechanical energy economy during normal walking by able-bodied subjects.     

Age-related differences in Tai Chi gait kinematics and leg muscle electromyography: a pilot study

Wu G. Age-related differences in Tai Chi gait kinematics and leg muscle electromyography: a pilot study.

Objective

To compare the biomechanic features of Tai Chi gait by elders with those by young adults, and with those of normative gait.

Design

Cross-sectional study.

Setting

Laboratory-based testing.

Participants

Young (n=6; 3 women) and old (n=6; 5 women) Tai Chi practitioners.

Intervention

All subjects had practiced Tai Chi for at least 4 months.

Main Outcome Measures

Spatial, temporal, and leg muscle electromyography during Tai Chi gait and normative gait.

Results

The primary age-related differences in Tai Chi gait were during single stance, with elders having significantly shorter single-stance time (−50%), less lateral displacement (-30%), knee flexion (-42%), hip flexion (-39%), activation time in the tibialis anterior (-13%), soleus (-39%), and tensor fascia lata (TFL) (-21%), activation magnitude in the tibialis anterior (-39%), and coactivation time of the tibialis anterior and soleus (-47%). Compared with normative gait, elders during Tai Chi gait had significantly larger knee (139%) and hip (66%) flexions, longer duration (90%-170%) and higher magnitude (200%-400%) of the tibialis anterior, rectus femoris, and TFL muscle activities, and longer duration of coactivation of most leg muscle pairs (130%-380%).

Conclusions

The elders practice Tai Chi gait in higher posture than younger subjects. The Tai Chi gait poses significantly higher challenges to elder’s balance and muscular system than does their normative gait.     

Gait Analysis for Evaluating the Relationship Between Increased Signal Intensity on T2-Weighted Magnetic Resonance Imaging and Gait Function in Cervical Spondylotic Myelopathy

Kim CR, Yoo JY, Lee SH, Lee DH, Rhim SC. Gait analysis for evaluating the relationship between increased signal intensity on T2-weighted magnetic resonance imaging and gait function in cervical spondylotic myelopathy.

Objective

To determine relationships between increased signal intensity (ISI) on T2-weighted cervical spine magnetic resonance imaging (MRI) and parameters of gait analysis in patients with cervical spondylotic myelopathy (CSM).

Design

Retrospective comparative study.

Setting

Gait analysis laboratory.

Participants

Patients (N=36) who undertook cervical laminectomy or laminoplasty because of CSM.

Interventions

Not applicable.

Main Outcome Measures

Subjects were evaluated by using the modified Japanese Orthopaedic Association (JOA) scale, the Nurick scale, cervical spine MRI, and gait analysis. Two radiologists classified patients into 3 groups: intense, faint, and no ISI.

Results

Relative to patients without ISI, those with ISI showed significantly slower gait speed, longer step time, decreased single-limb support time, increased double-limb support time, and limited range of motion of knee and ankle (P<.05). Increased intensity tended to correlate with poor gait function including slower gait speed, longer step time, decreased single-limb support time, and increased double-limb support time. The modified JOA and Nurick scale did not correlate with ISI.

Conclusions

In patients with CSM who received surgical treatment, more intense ISI on T2-weighted MRI correlated preoperatively with increased difficulties in gait function. Gait analysis may be a useful tool for evaluating gait functions in cervical myelopathy.