Double Stance Duration Research Articles

Classification and Definitions of Compensatory Protective Step Strategies in Older Adults: A Scoping Review.

The risk for an unexpected fall can be due to increasing age, health conditions, and loss of cognitive, sensory, or musculoskeletal functions. Falls have personal and economic consequences in many countries. Different disturbances can occur during gait, such as tripping, slipping, or other unexpected circumstances that can generate a loss of balance. The strategies used to recover balance depend on many factors, but selecting a correct response strategy influences the success of balance recovery. (1) To collect and clarify the definitions of compensatory protective step strategies to recover balance in older adults; (2) to identify the most used methods to induce loss of balance; and (3) to identify the most used spatiotemporal variables in analyzing these actions. The present review has followed the PRISMA guideline extension for Scoping Review (PRISMA-ScR) and the phases proposed by Askery and O'Malley. The search was conducted in three databases: PubMed, Web of Science, and Scopus. A total of 525 articles were identified, and 53 studies were included. Forty-five articles were quasi-experimental studies, six articles were randomized controlled trials, and two studies had an observational design. In total, 12 compensatory protective step strategies have been identified. There are 12 compensatory protective step strategies: lowering and elevating strategy, short- and long-step strategy, backward and forward stepping for slip, single step, multiple steps, lateral sidesteps or loaded leg sidestep unloaded leg sidestep, crossover step (behind and front), and medial sidestep. To standardize the terminology applied in future studies, we recommend collecting these strategies under the term of compensatory protective step strategies. The most used methods to induce loss of balance are the tether-release, trip, waist-pull, and slip methods. The variables analyzed by articles are the number of steps, the acceleration phase and deceleration phase, COM displacement, the step initiation or step duration, stance phase time, swing phase time and double-stance duration, stride length, step length, speed step, speed gait and the type of step.

Stimulation of the pedunculopontine and cuneiform nuclei for freezing of gait and falls in Parkinson disease: Cross-over single-blinded study and long-term follow-up

IntroductionDeep brain stimulation (DBS) of the mesencephalic locomotor region, composed of the pedunculopontine (PPN) and cuneiform (CuN) nuclei, has been proposed to treat dopa-resistant gait and balance disorders in Parkinson's disease (PD). Here, we report the long-term effects of PPN- or CuN-DBS on these axial disorders. MethodsIn 6 PD patients operated for mesencephalic locomotor region DBS and prospectively followed for more than 2 years, we assessed the effects of both PPN- and CuN-DBS (On-dopa) in a cross-over single-blind study by using clinical scales and recording gait parameters. Patients were also examined Off-DBS. ResultsMore than 2 years after surgery, axial and Tinetti scores were significantly aggravated with both PPN- or CuN-DBS relative to before and one year after surgery. Gait recordings revealed an increased double-stance duration with both PPN- or CuN-DBS, higher swing phase duration with CuN-DBS and step width with PPN-DBS. With PPN- versus CuN-DBS, the step length, velocity and cadence were significantly higher; and the double-stance and turn durations significantly lower. Irrespective the target, we found no significant change in clinical scores Off-DBS compared to On-DBS. The duration of anticipatory postural adjustments as well as step length were lower with versus without PPN-DBS. We found no other significant changes in motor, cognitive or psychiatric scores, except an increased anxiety severity. ConclusionIn this long-term follow-up study with controlled assessments, PPN- or CuN-DBS did not improve dopa-resistant gait and balance disorders with a worsening of these axial motor signs with time, thus indicating no significant clinical effect.

Extraction of gait parameters from marker-free video recordings of Timed Up-and-Go tests: Validity, inter- and intra-rater reliability.

We study dual-task performance with marker-free video recordings of Timed Up-and-Go tests (TUG) and TUG combined with a cognitive/verbal task (TUG dual-task, TUGdt). Can gait parameters be accurately estimated from video-recorded TUG tests by a new semi-automatic method aided by a technique for human 2D pose estimation based on deep learning? Thirty persons aged 60-85 years participated in the study, conducted in a laboratory environment. Data were collected by two synchronous video-cameras and a marker-based optoelectronic motion capture system as gold standard, to evaluate the gait parameters step length (SL), step width (SW), step duration (SD), single-stance duration (SSD) and double-stance duration (DSD). For reliability evaluations, data processing aided by a deep neural network model, involved three raters who conducted three repetitions of identifying anatomical keypoints in recordings of one randomly selected step from each of the participants. Validity was analysed using 95 % confidence intervals (CI) and p-values for method differences and Bland-Altman plots with limits of agreement. Inter- and intra-rater reliability were calculated as intraclass correlation coefficients (ICC) and standard errors of measurement. Smallest detectable change was calculated for inter-rater reliability. Mean ddifferences between video and the motion capture system data for SW, DSD, and SSD were significant (p < 0.001). However, mean differences for all parameters were small (-6.4%-13.0% of motion capture system) indicating good validity. Concerning reliability, almost all 95 % CI of the ICC estimates exceeded 0.90, indicating excellent reliability. Only inter-rater reliability for SW (95 % CI = 0.892;0.973) and one rater's intra-rater reliability for SSD (95 % CI = 0.793;0.951) were lower, but still showed good to excellent reliability. The presented method for extraction of gait parameters from video appears suitable for valid and reliable quantification of gait. This opens up for analyses that may contribute to the knowledge of cognitive-motor interference in dual-task testing.

PPNa-DBS for gait and balance disorders in Parkinson's disease: a double-blind, randomised study.

Gait and balance disorders are the major source of motor disabilities in advanced forms of Parkinson's disease (PD). Low-frequency stimulation of the pedunculopontine nucleus area (PPNa-DBS) has been recently proposed to treat these symptoms with variable clinical results. To further understand the effects of PPNa-DBS on resistant gait and balance disorders, we performed a randomised double-blind cross-over study in six PD patients. Evaluation included clinical assessment of parkinsonian disability, quality of life and neurophysiological recordings of gait. Evaluations were done 1 month before, 4 and 6 months after surgery with four double-blinded conditions assessed: with and without PPNa-DBS, with and without levodopa treatment. Four patients completed the study and two patients were excluded from the final analysis because of peri-operative adverse events (haematoma, infection). Clinically, the combination of PPNa-DBS and levodopa treatment produced a significant decrease of the freezing episodes. The frequency of falls also decreased in three out of four patients. From a neurophysiological point of view, PPNa-DBS significantly improved the anticipatory postural adjustments and double-stance duration, but not the length and speed of the first step. Interestingly, step length and speed improved after surgery without PPNa-DBS, suggesting that the lesioning effect of PPNa-DBS surgery alleviates parkinsonian akinesia. Quality of life was also significantly improved with PPNa-DBS. These results suggest that PPNa-DBS could improve gait and balance disorders in well-selected PD patients. However, this treatment may be riskier than others DBS surgeries in these patients with an advanced form of PD.

Spatial-Temporal Gait Characteristics in Individuals With Hip Osteoarthritis: A Systematic Literature Review and Meta-analysis

Systematic literature review and meta-analysis. To systematically review and critically evaluate the literature to determine how basic gait characteristics are altered in individuals with hip osteoarthritis (OA). Hip OA is a progressive musculoskeletal condition that leads to pain, stiffness, and functional limitation in activities such as walking. Understanding gait dysfunction in people with hip OA may contribute to more effective management of the disease. Eleven electronic research databases were searched. Studies comparing basic gait parameters in individuals with hip OA to healthy controls and the affected to the contralateral limb of individuals with hip OA were included. The studies were critically appraised for methodological quality. Available data were extracted, and meta-analysis was performed, with standardized effect sizes (Cohen d) and corresponding 95% confidence intervals computed for gait speed, cadence, step and stride length, stance, swing and double-stance duration, and step width. The final analysis included 30 articles. Self-selected gait speed was 26% slower in individuals with hip OA relative to controls, which was explained by shorter stride length. Consistent evidence was found for greater asymmetry in individuals with hip OA than controls, with shorter step length and stance duration in the affected compared to the contralateral limb. Individuals with hip OA walk at a slower speed and exhibit greater gait asymmetry than controls. Gait speed and asymmetry can be readily assessed clinically and represent a simple way of objectively evaluating gait dysfunction and monitoring treatment progress in individuals with hip OA.

Test-Retest Reliability of the Win-Track Platform in Analyzing the Gait Parameters and Plantar Pressures During Barefoot Walking in Healthy Adults

The Win-Track platform is an instrument used to measure plantar pressures and gait parameters during barefoot walking. The objective of this study was to determine the test-retest reliability of the system in assessing plantar pressures and temporal gait variables between 1-step and 3-step gait protocols. A total of 30 healthy participants (18 women and 12 men; age 23.7 ± 4.75 years) were recruited for the study. The 1-step gait protocol exhibited good reliability in terms of single stance, step duration and swing duration of the left foot; stride duration of the right foot; stride length; and step length of the right foot, with intraclass correlation coefficients (ICCs) ranging from 0.75 to 0.88. The 3-step gait protocol showed good reliability, with ICC values ranging between 0.75 and 0.90 in cadence; step duration of the right foot; double-stance duration and swing duration of the right foot; stride length of the right foot; step length and gait cycle length of the right and the left foot; and the area covered by the first, second, and third foot. The authors concluded that the Win-Track platform provided reliable plantar pressures and temporal gait measures, and the 3-step gait protocol showed better reliability compared with the 1-step gait protocol.

Expression of Sensory Neuropeptides in Tendon is Associated with Failed Healing and Activity-Related Tendon Pain in Collagenase-Induced Tendon Injury

Background Increase in expression of substance P (SP) and calcitonin gene-related peptide (CGRP) has been reported in clinical samples of tendinopathy. Purpose To examine the spatial-temporal expression of these neuropeptides as well as their association with activity-related tendon pain, matrix degeneration, failed healing, and pathologic calcification in an established collagenase-induced tendon injury rat model. Study Design Controlled laboratory study. Methods Collagenase or saline was injected into the patellar tendon of rats. At weeks 2, 4, 8, 12, and 16, just before the rats were sacrificed, the double-stance duration of rats was examined by gait analysis method. After sacrifice, the patellar tendons were harvested for histologic analysis and immunohistochemical staining of SP and CGRP. Results There was an increase of SP and CGRP immunopositivity in tendon fibroblasts at week 2. The immunopositive signals decreased at weeks 4 and 8 and were observed in chondrocyte-like cells. At weeks 12 and 16, the immunopositive staining increased again and was observed in cells embedded in calcific deposits in addition to tendon fibroblasts and chondrocyte-like cells. The expression pattern was consistent with matrix degeneration, calcification, and failed healing in the animal model. There were significant positive correlations of immunopositivity of SP (rho = .502, P = .002) and CGRP (rho = .483, P = .003) with double-stance duration after collagenase injection. Conclusion There was increased expression of SP and CGRP after collagenase-induced tendon injury, and their expression was positively associated with double-stance duration. Clinical Relevance Substance P and CGRP might be involved in the pathogenesis and origin of pain of tendinopathy and could be the targets for future intervention.

The use of motion analysis to measure pain-related behaviour in a rat model of degenerative tendon injuries

Chronic tendinopathy is characterized with longstanding activity-related pain with degenerative tendon injuries. An objective tool to measure painful responses in animal models is essential for the development of effective treatment for tendinopathy. Gait analysis has been developed to monitor the inflammatory pain in small animals. We reported the use of motion analysis to monitor gait changes in a rat model of degenerative tendon injury. Intratendinous injection of collagenase into the left patellar tendon of Sprague Dawley rat was used to induce degenerative tendon injury, while an equal volume of saline was injected in the control groups. Motion analyses with a high speed video camera were performed on all rats at pre-injury, 2, 4, 8, 12 or 16 weeks post injection. In the end-point study, the rats were sacrificed to obtain tendon samples for histological examination after motion analyses. In the follow-up study, repeated motion analyses were performed on another group of collagenase-treated and saline-treated rats. The results showed that rats with injured patellar tendon exhibited altered walking gait as compared to the controls. The change in double stance duration in the collagenase-treated rats was reversible by administration of buprenorphrine ( p = 0.029), it suggested that the detected gait changes were associated with pain. Comparisons of end-point and follow-up studies revealed the confounding effects of training, which led to higher gait velocities and probably a different adaptive response to tendon pain in the trained rats. The results showed that motion analysis could be used to measure activity-related chronic tendon pain.

Predictive modelling of human walking over a complete gait cycle

An inverse dynamics multi-segment model of the body was combined with optimisation techniques to simulate normal walking in the sagittal plane on level ground. Walking is formulated as an optimal motor task subject to multiple constraints with minimisation of mechanical energy expenditure over a complete gait cycle being the performance criterion. All segmental motions and ground reactions were predicted from only three simple gait descriptors (inputs): walking velocity, cycle period and double stance duration. Quantitative comparisons of the model predictions with gait measurements show that the model reproduced the significant characteristics of normal gait in the sagittal plane. The simulation results suggest that minimising energy expenditure is a primary control objective in normal walking. However, there is also some evidence for the existence of multiple concurrent performance objectives.

Influence of Speed Variation and Age on Ground Reaction Forces and Stride Parameters of Children's Normal Gait

The aim of this study was to assess the influence of both age and speed on ground reaction forces and temporal parameters during normal gait in children. Fifteen children aged 4-6 years (group 1), 16 aged 6-8 years (group 2), and 16 aged 8-10 years (group 3) walked at 2.7 km/h, 3.6 km/h, and 4.5 km/h on a treadmill. For each child thirty successive steps were recorded. The influence of speed and age on normalized gait parameters was examined with two-way analysis of variance. The first vertical peak force (Fz1) and all the antero-posterior forces of group 1 were higher than those of the other groups for the three speeds. The minimum vertical force (Fz2), the second vertical peak force (Fz3), and the duration of stride and stance were significantly higher in groups 2 and 3. For all the groups, Fz1 and all the antero-posterior forces increased with the speed while Fz2, stride, stance, and double-stance duration decreased. Fz3 was not influenced by speed variation. The results of this study show that age and walking speed influence ground reaction forces and stride time parameters in 4- to 10-year-old children.

Immediate effects of speed-dependent treadmill training on gait parameters in early Parkinson’s disease

Pohl M, Rockstroh G, Rückriem S, Mrass G, Mehrholz J. Immediate effects of speed-dependent treadmill training on gait parameters in early Parkinson’s disease. Arch Phys Med Rehabil 2003;84:1760–6. Objective To compare the immediate effects of different training interventions on gait parameters in patients with early Parkinson’s disease (PD). Design Randomized, multiple intervention crossover pilot study. Setting A rehabilitation center for adult persons with neurologic disorders. Participants Seventeen patients with early PD (Hoehn and Yahr stages I through III) and gait disturbances. Intervention Patients were randomly assigned to varying sequences of the following interventions over 4 consecutive days: structured speed-dependent treadmill training (STT), limited progressive treadmill training (LTT), conventional gait training (CGT), and a control intervention. Main outcome measures Basic gait parameters (overground walking speed and stride length at self-adapted speeds) and parameters of gait analysis based on vertical ground reaction forces. Results STT and LTT improved all basic gait parameters and the double stance duration compared with preintervention values ( P<.05). No changes were found after CGT and the control intervention ( P<.05). Significantly higher gains were observed in all basic gait parameters after STT and LTT when compared with CGT and the control intervention ( P<.05). Additionally, a greater reduction of double stance duration was found after STT than after the control intervention ( P<.001). No significant differences in gains were observed between STT and LTT, or between CGT and the control intervention, in all gait parameters. Conclusion The main disturbances of gait in PD, namely, speed and stride length, can be improved through a single intervention of STT or LTT, but not through CGT and the control intervention.

Effect of hindlimb unloading on interlimb coordination during treadmill locomotion in the rat.

Effects of hindlimb unloading on interlimb coordination were examined in adult rats walking on a treadmill at moderate speed. In the first group of animals, the electromyographic activity (EMG) of soleus muscle of both hindlimbs was recorded after 7 and 14 days of unloading. In the second group, the EMG was recorded daily until the 14th day of unloading. The general organization of locomotion was preserved in the two groups whatever the duration of the unloading. The step cycles of the two hindlimbs were always strictly alternating. However, the locomotor pattern was very irregular. A lateral instability was observed. It was accompanied by an abduction of the hindlimbs, and frequent hyperextensions of the ankle when walking. The EMG analysis showed an increase in step cycle duration and in coactivation duration of the soleus muscles (i.e. in the double stance duration). In the rats recorded daily, mean EMG was dramatically reduced the 1st day of unloading, suggesting a decrease in the neural drive. Taken together, these data indicate that 14 days of hindlimb unloading can alter the neuromuscular pattern during locomotion. It is proposed that these changes are related to changes in the peripheral sensory information.