Self-selected Walking Speed Research Articles

The Kinetic and Kinematic Efficacy of Posterior Leaf Spring Ankle-foot Orthosis in Patients with Drop foot

Background: Dorsi flexor weakness is one of the common consequences of stroke with a negative impact on normal walking. Posterior leaf spring (PLS) Ankle Foot Orthosis (AFO) is the most frequent prescription to assist foot clearance and leg propulsion in these patients. However, the real efficacy of this AFO needs more attention. This study aimed to investigate the efficacy of PLS AFO on gait outcomes as the most common AFO in drop foot post-stroke patients. Methods: The study design was a pre–post-test experiments in which twenty drop foot patients with a mean age of 65 years with a mean age of 58.45 (±5.23) years who were 4/5 years post-stroke. They walked at self-selected walking speed on a 10 meters walk away in two conditions of with their own shoes and PLS AFO. The 3D motion capture gait analysis system including 6 vicon cameras and a Kistler force plate were used in order to measure gait kinetic and kinematic variables. For each trial, each joints (ankle, knee and hip) angle, moment and power were averaged over one-minute walking. Results: Walking with PLS showed a statistically significant improve kinetic and kinematic variables in hip, knee and ankle joints included power, moments and angles at entire gait cycle. P<0.05. Conclusions: In our study of stroke patients who were fitted with a PLS AFO, immediate significant improvements occurred in most kinetic and kinematic than shoes only in sacrifice some others.

One-year budget impact of InTandem™: a novel neurorehabilitation system for individuals with chronic stroke walking impairment.

Aim: Chronic stroke walking impairment is associated with high healthcare resource utilization (HCRU) costs. InTandem™ is a neurorehabilitation system that autonomously delivers a rhythmic auditory stimulation (RAS)-based intervention for the at-home rehabilitation of walking impairment in adults in the chronic phase of stroke recovery. This study was conducted to estimate the budget impact of InTandem in comparison with currently available intervention strategies for improvement of gait/ambulation in individuals with chronic stroke walking impairment. Methods & materials: A budget impact analysis (BIA) for InTandem was conducted based on a 1-million-member US third-party payer perspective over a 1-year time horizon. Key inputs for the budget impact model were: costs for each intervention strategy (InTandem, physical therapy, self-directed walking and no treatment), HCRU costs for persons with chronic stroke and anticipated HCRU cost offsets due to improvements in gait/ambulatory status as measured by self-selected comfortable walking speed (based on functional ability). In addition to the reference case analysis, a sensitivity analysis was conducted. Results: Based on the reference case, introduction of InTandem was projected to result in overall cost savings of $439,954 in one year. Reduction of HCRU costs (-$2,411,778) resulting from improved walking speeds with InTandem offset an increase in intervention costs (+$1,971,824). Demonstrations of cost savings associated with InTandem were robust and were consistently evident in nearly all scenarios evaluated in the sensitivity analysis (e.g., with increased/decreased patient shares, increased HCRU costor increased InTandem rental duration). Conclusion: The InTandem system is demonstrated to improve walking and ambulation in adults in the chronic phase of stroke recovery after a five-week intervention period. The BIA predicts that introduction of InTandem will be associated with overall cost savings to the payer.

Alpha and beta/low-gamma frequency bands may have distinct neural origin and function during post-stroke walking.

Plantarflexors provide propulsion during walking and receive input from both corticospinal and corticoreticulospinal tracts, which exhibit some frequency-specificity that allows potential differentiation of each tract's descending drive. Given that stroke may differentially affect each tract and impair the function of plantarflexors during walking; here, we examined this frequency-specificity and its relation to walking-specific measures during post-stroke walking. Fourteen individuals with chronic stroke walked on an instrumented treadmill at self-selected and fast walking speed (SSWS and FWS, respectively) while surface electromyography (sEMG) from soleus (SOL), lateral gastrocnemius (LG), and medial gastrocnemius (MG) and ground reaction forces (GRF) were collected. We calculated the intermuscular coherences (IMC; alpha, beta, and low-gamma bands between SOL-LG, SOL-MG, LG-MG) and propulsive impulse using sEMG and GRF, respectively. We examined the interlimb and intralimb IMC comparisons and their relationships with propulsive impulse and walking speed. Interlimb IMC comparisons revealed that beta LG-MG (SSWS) and low-gamma SOL-LG (FWS) IMCs were degraded on the paretic side. Intralimb IMC comparisons revealed that only alpha IMCs (both speeds) exhibited a statistically significant difference to random coherence. Further, alpha LG-MG IMC was positively correlated with propulsive impulse in the paretic limb (SSWS). Alpha and beta/low-gamma bands may have a differential functional role, which may be related to the frequency-specificity of the underlying descending drives. The persistence of alpha band in plantarflexors and its strong positive relationship with propulsive impulse suggests relative alteration of corticoreticulospinal tract after stroke. These findings imply the presence of frequency-specific descending drives to walking-specific muscles in chronic stroke.

Customized passive-dynamic ankle–foot orthoses can improve walking economy and speed for many individuals post-stroke

BackgroundPassive-dynamic ankle–foot orthoses (PD-AFOs) are often prescribed to address plantar flexor weakness during gait, which is commonly observed after stroke. However, limited evidence is available to inform the prescription guidelines of PD-AFO bending stiffness. This study assessed the extent to which PD-AFOs customized to match an individual’s level of plantar flexor weakness influence walking function, as compared to No AFO and their standard of care (SOC) AFO.MethodsMechanical cost-of-transport, self-selected walking speed, and key biomechanical variables were measured while individuals greater than six months post-stroke walked with No AFO, with their SOC AFO, and with a stiffness-customized PD-AFO. Outcomes were compared across these conditions using a repeated measures ANOVA or Friedman test (depending on normality) for group-level analysis and simulation modeling analysis for individual-level analysis.ResultsTwenty participants completed study activities. Mechanical cost-of-transport and self-selected walking speed improved with the stiffness-customized PD-AFOs compared to No AFO and SOC AFO. However, this did not result in a consistent improvement in other biomechanical variables toward typical values. In line with the heterogeneous nature of the post-stroke population, the response to the PD-AFO was highly variable.ConclusionsStiffness-customized PD-AFOs can improve the mechanical cost-of-transport and self-selected walking speed in many individuals post-stroke, as compared to No AFO and participants’ standard of care AFO. This work provides initial efficacy data for stiffness-customized PD-AFOs in individuals post-stroke and lays the foundation for future studies to enable consistently effective prescription of PD-AFOs for patients post-stroke in clinical practice.Trial Registration: NCT04619043.

Differences in knee joint moments between individuals who are living with obesity and those of a healthy weight when negotiating stairs

BackgroundIndividuals who are living with obesity often adopt alternative lower limb walking mechanics compared to persons with a healthy weight. Stair negotiation is a common activity of daily living that, when used consistently with diet and other physical activity, can help promote the reversal of health-related risk factors associated with people who are obese. The purpose of this study was to determine how stair negotiation affects normalized and non-normalized peak knee extension and abduction moments in young adults who live with obesity (BMI between 30 and 40 kg/m2) compared to adults with a healthy weight (BMI between 18.5 and 25 kg/m2). MethodsFifteen young adults living with obesity and fifteen with a healthy weight performed stair ascent and descent walking trials on a 3-step instrumented staircase at a self-selected walking speed. A one-way ANCOVA (covariate: gait speed) was used to compare knee moment variables between groups. ResultsNo significant differences were found between groups in peak knee joint moments normalized to body mass. The individuals living with obesity demonstrated significantly larger non-normalized peak knee extension moments during stair ascent and descent but no differences in the non-normalized peak knee abduction moments for stair ascent or descent. ConclusionResults of this study indicate differences in non-normalized peak knee extension moments between BMI groups. The young age of the obese group may have contributed to minimal differences overall. Future research should determine how these findings differ in an older obese population and how using a handrail would affect these results.

Heteronymous feedback from quadriceps onto soleus in stroke survivors.

Recent findings suggest increased excitatory heteronymous feedback from quadriceps onto soleus may contribute to abnormal coactivation of knee and ankle extensors after stroke. However, there is lack of consensus on whether persons post-stroke exhibit altered heteronymous reflexes and, when present, the origin of increased excitation (i.e. increased excitation alone and/or decreased inhibition). This study examined heteronymous excitation and inhibition from quadriceps onto soleus in paretic, nonparetic, and age-matched control limbs to determine whether increased excitation was due to excitatory and/or reduced inhibitory reflex circuits. A secondary purpose was to examine whether heteronymous reflex magnitudes were related to clinical measures of lower limb recovery, walking-speed, and dynamic balance. Heteronymous excitation and inhibition from quadriceps onto soleus were examined in fourteen persons post-stroke and fourteen age-matched unimpaired participants. Heteronymous feedback was elicited by femoral nerve and quadriceps muscle stimulation in separate trials while participants tonically activated soleus at 20% max. Fugl-Myer assessment of lower extremity, 10-meter walk test, and Mini-BESTest were assessed in stroke survivors. Heteronymous excitation and inhibition onsets, durations, and magnitudes were not different between paretic, nonparetic or age-matched unimpaired limbs. Quadriceps stimulation elicited excitation that was half the magnitude of femoral nerve stimulation. Femoral nerve elicited paretic limb heteronymous excitation was positively correlated with walking speed but did not reach significance because only a subset of paretic limbs exhibited excitation (n = 8, Spearman r = 0.69, P = 0.058). Heteronymous feedback from quadriceps onto soleus assessed in a seated posture was not impaired in persons post-stroke. Despite being unable to identify whether reduced inhibition contributes to abnormal excitation reported in prior studies, our results indicate quadriceps stimulation may allow a better estimate of heteronymous inhibition in those that exhibit exaggerated excitation. Heteronymous excitation magnitude in the paretic limb was positively correlated with self-selected walking speed suggesting paretic limb excitation at the higher end of a normal range may facilitate walking ability after stroke. Future studies are needed to identify whether heteronymous feedback from Q onto SOL is altered after stroke in upright postures and during motor tasks as a necessary next step to identify mechanisms underlying motor impairment.

Improving trunk posture control in children with CP through a cable-driven robotic hippotherapy: A randomized controlled feasibility study

BackgroundMany children with cerebral palsy (CP) show impairments in trunk posture control, one crucial factor contributing to impairments in gait and arm manipulation. Research questionThe goal of this study was to test the feasibility of the cable-driven hippotherapy system on improving trunk posture control and walking function in children with CP. MethodTen children were recruited in this study with average age 6.4 ± 3.0 years old, and were randomly assigned to the robotic group and the conventional balance training group. A custom designed cable-driven robotic hippotherapy system was used to deliver controlled pelvis perturbations while children were sitting astride. Participants from both groups underwent intensive robotic hippotherapy training or conventional balance training, depending on their group assignment, for 6 weeks (3 time/week). Outcome measures were assessed pre and post 6 weeks of robotic or conventional balance training, and 8 weeks after the end of training (follow-up test). The primary outcome measure was trunk control, which was measured using the Trunk Control Measurement Scale (TCMS). In addition, the Gross Motor Function Measure (GMFM-66), self-selected overground walking speed, and 6-minute walking distance were also assessed. ResultsThe change in TCMS score from baseline to the post intervention was significantly greater for the robotic group than that for the conventional group (i.e., 6 ± 3 vs. −1 ± 5, p = 0.048, Mann-Whitney test). GMFM scores, self-selected overground walking speed, and 6-minute walking distance showed no significant improvement after robotic hippotherapy and after conventional balance training (p > 0.05). SignificanceResults from this study indicated that it was feasible to improve trunk posture control in children with CP using a cable-driven robotic hippotherapy system. Knowledge obtained from this study may provide an insight for the development of new perturbation-based intervention approaches for improving trunk posture control in children with CP.

Age related progression of lower limb coordination during gait in children with cerebral palsy without a history of surgical intervention

Walking requires precise movement between body segments, referred to as intersegmental coordination, which is an important factor in efficient motor performance. For children with cerebral palsy (CP), who often demonstrate an impaired neuromuscular system, intersegmental coordination has been shown to be different when compared to their typically developed (TD) peers. However, how intersegmental coordination changes over time in these children is unclear. The aim of this study was to quantify age-related changes in intersegmental coordination in children with bilateral CP without a history of surgical intervention and to compare to control groups of children with TD of similar age, weight, and height. A retrospective analysis of 162 children with bilateral CP who had a baseline and follow-up 3D gait assessment, and no history of surgical intervention, was conducted. Two age, weight, and height control groups of children with TD were included. A full 3-dimensional kinematic analysis was performed, and continuous relative phase analysis of the thigh-shank and shank-foot, while walking at a self-selected walking speed, was used to measure intersegmental coordination. Differences were present for children with CP compared to children with TD at baseline for thigh-shank intersegmental coordination. However, children with CP demonstrated a change over time with a move towards TD patterns at follow-up assessment. This study provides insights into the acquisition and stabilisation of intersegmental coordination between children with CP and TD.

Dynamic gait stability and stability symmetry for people with transfemoral amputation: A case-series of 19 individuals with bone-anchored limbs

For some individuals with severe socket-related problems, prosthesis osseointegration directly connects a prosthesis to the residual limb creating a bone-anchored limb (BAL). We compared dynamic gait stability and between-limb stability symmetry, as measured by the Margin of Stability (MoS) and the Normalized Symmetry Index (NSI), for people with unilateral transfemoral amputation before and one-year after BAL implantation. The MoS provides a mechanical construct to assess dynamic gait stability and infer center of mass and limb control by relating the center of mass and velocity to the base of support. Before and one-year after BAL implantation, 19 participants walked overground at self-selected speeds. We quantified dynamic gait stability anteriorly and laterally at foot strike and at the minimum lateral MoS value. After implantation, we observed decreased lateral MoS at foot strike for the amputated (MoS mean(SD) %height; pre: 6.6(2.3), post: 5.9(1.3), d = 0.45) and intact limb (pre: 6.2(1.2), post: 5.8(1.0), d = 0.38) and increased between-limb MoS symmetry at foot strike (NSI mean(SD) %; anterior–pre: 10.3(7.3), post: 8.4(3.6), d = 0.23; lateral–pre: 18.8(12.4), post: 12.4(4.9), d = 0.47) and at minimum lateral stability (pre: 28.1(18.1), post: 19.2(6.8), d = 0.50). Center of mass control using a BAL resulted in dynamic gait stability more similar between limbs and may have reduced the adoption of functional asymmetries. We suggest that improved between-limb MoS symmetry after BAL implantation is likely due to subtle changes in individual limb MoS values at self-selected walking speeds resulting in an overall positive impact on fall risk through improved center of mass and prosthetic limb control.

Cognitive-Behavioral-Based Physical Therapy for Improving Recovery After a Traumatic Lower-Extremity Injury: The Results of a Randomized Controlled Trial.

Lower-extremity injuries can result in severe impairment and substantial years lived with a disability. Persistent pain and psychological distress are risk factors for poor long-term outcomes and negatively influence the recovery process following a traumatic injury. Cognitive-behavioral therapy (CBT) interventions have the potential to address these risk factors and subsequently improve outcomes. This study aimed to evaluate the effect of a telephone-delivered cognitive-behavioral-based physical therapy (CBPT) program on physical function, pain, and general health at 12 months after hospital discharge following lower-extremity trauma. The CBPT program was hypothesized to improve outcomes compared with an education program. A multicenter, randomized controlled trial was conducted involving 325 patients who were 18 to 60 years of age and had at least 1 acute orthopaedic injury to the lower extremity or to the pelvis or acetabulum requiring operative fixation. Patients were recruited from 6 Level-I trauma centers and were screened and randomized to the CBPT program or the education program early after hospital discharge. The primary outcome was the Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) scale. The secondary outcomes were objective physical function tests (4-square step test, timed stair ascent test, sit-to-stand test, and self-selected walking speed test), PROMIS Pain Intensity and Pain Interference, and the Veterans RAND 12-Item Health Survey. Treatment effects were calculated using targeted maximum likelihood estimation, a robust analytical approach appropriate for causal inference with longitudinal data. The mean treatment effect on the 12-month baseline change in PROMIS PF was 0.94 (95% confidence interval, -0.68 to 2.64; p = 0.23). There were also no observed differences in secondary outcomes between the intervention group and the control group. The telephone-delivered CBPT did not appear to yield any benefits for patients with traumatic lower-extremity injuries in terms of physical function, pain intensity, pain interference, or general health. Improvements were observed in both groups, which questions the utility of telephone-delivered cognitive-behavioral strategies over educational programs. Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Changes in walking function and neural control following pelvic cancer surgery with reconstruction.

Introduction: Surgical planning and custom prosthesis design for pelvic cancer patients are challenging due to the unique clinical characteristics of each patient and the significant amount of pelvic bone and hip musculature often removed. Limb-sparing internal hemipelvectomy surgery with custom prosthesis reconstruction has become a viable option for this patient population. However, little is known about how post-surgery walking function and neural control change from pre-surgery conditions. Methods: This case study combined comprehensive walking data (video motion capture, ground reaction, and electromyography) with personalized neuromusculoskeletal computer models to provide a thorough assessment of pre- to post-surgery changes in walking function (ground reactions, joint motions, and joint moments) and neural control (muscle synergies) for a single pelvic sarcoma patient who received internal hemipelvectomy surgery with custom prosthesis reconstruction. Pre- and post-surgery walking function and neural control were quantified using pre- and post-surgery neuromusculoskeletal models, respectively, whose pelvic anatomy, joint functional axes, muscle-tendon properties, and muscle synergy controls were personalized using the participant's pre-and post-surgery walking and imaging data. For the post-surgery model, virtual surgery was performed to emulate the implemented surgical decisions, including removal of hip muscles and implantation of a custom prosthesis with total hip replacement. Results: The participant's post-surgery walking function was marked by a slower self-selected walking speed coupled with several compensatory mechanisms necessitated by lost or impaired hip muscle function, while the participant's post-surgery neural control demonstrated a dramatic change in coordination strategy (as evidenced by modified time-invariant synergy vectors) with little change in recruitment timing (as evidenced by conserved time-varying synergy activations). Furthermore, the participant's post-surgery muscle activations were fitted accurately using his pre-surgery synergy activations but fitted poorly using his pre-surgery synergy vectors. Discussion: These results provide valuable information about which aspects of post-surgery walking function could potentially be improved through modifications to surgical decisions, custom prosthesis design, or rehabilitation protocol, as well as how computational simulations could be formulated to predict post-surgery walking function reliably given a patient's pre-surgery walking data and the planned surgical decisions and custom prosthesis design.

The effect of time normalization and biomechanical signal processing techniques of ground reaction force curves on deep-learning model performance

Time-series data are common in biomechanical studies. These data often undergo pre-processing steps such as time normalization or filtering prior to use in further analyses, including deep-learning classification. In this context, it remains unclear how these preprocessing steps affect deep-learning model performance. Thus, the aim of this study is to assess the effect of time-normalization and filtering on the performance of deep-learning classification models. We also investigated the effect of amplitude scaling. Using a public dataset (Gutenburg Gait Database, a ground reaction force database of level overground walking at self-selected walking speed involving 350 healthy individuals), we trained convolutional neural network (CNN) and long short-term memory (LSTM) models to predict binary sex (male, female) using three-dimensional ground-reaction forces to which we applied different processing approaches: zero padding, interpolation to 100% of signal, filtering, and scaling (min–max, body mass). The results show that transformations resulted in differences in model performances. Highest performance was obtained using unfiltered data, zero-padding, and min–max amplitude scaling (F1-score of 91 and 87% for CNN and LSTM, respectively). Not filtering data and using min–max scaling generally improve performance for both model architectures. For interpolation, results are not consistent across model architectures. This study suggests that processing steps must be considered in applications where deep-learning classification performance is relevant.

Ankle Muscle Strength and Gait Function After Dorsal Closing Wedge Calcaneal Osteotomy for Haglund Exostosis-Related Heel Pain.

Haglund exostosis-related heel pain may be surgically treated with dorsal closing wedge calcaneal osteotomy (DCWCO). Recent reports on this technique show good clinical and self-reported outcomes. However, uncertainty about functional consequences related to ankle muscle strength and gait function due to a shortened Achilles tendon lever arm exists. Fifteen patients (15 feet) with Haglund exostosis-related heel pain were surgically treated with DCWCO and evaluated before and 1 year after surgery. Isometric plantar flexion and dorsiflexion strength was quantified for both the involved and the uninvolved limb. Gait analysis was performed at a self-selected walking speed using a 3D motion capture system including force plates. Self-reported outcomes (Foot Function Index and Global Treatment Outcome) were also assessed. Before surgery, as well as after surgery, plantar flexion strength of the involved limb was significantly lower compared to the uninvolved limb while dorsiflexion strength did not differ between limbs at both time points. Step length and time, ankle flexion angles, power generation, and propulsive impulses during gait did not differ between limbs both before and after surgery. Propulsive impulse and step length of the involved limb increased from pre- to postsurgery with an effect size of 1.04 and 0.48, respectively, revealing a general improvement in gait dynamics. Total Foot Function Index improved by 48% after surgery, and 80% of patients rated their surgery as "helped" or "helped a lot" (Global Treatment Outcome). In this relatively small cohort, we found that patients treated for Haglund exostosis-related heel pain with DCWCO surgery had minor interlimb differences in gait kinematics and kinetics and generally improved gait dynamics and self-reported function at 1-year follow-up. Level II, observational prospective cohort study.

Risk of unfavorable pain prognosis impacts walking physiomechanical parameters and psychophysiological workload in sufferers of chronic low back pain

BackgroundTolerating physical tasks depends not only on task-specific characteristics but also on an individual's psychophysiological capacity to respond to the imposed load. People suffering from chronic low back pain (CLBP) may experience reduced psychophysiological capacity and are at risk for poor pain prognosis, which could lead to an increased walking workload. AimTo investigate how the risk of unfavorable pain prognosis in CLBP can impact walking physiomechanical parameters and psychophysiological workload. MethodsA cross-sectional observational study. The study classified 74 volunteers into four groups based on their prognosis for pain: pain-free control (CG/n = 20), low (LrG/n = 21), medium (MrG/n = 22), and high (HrG/n = 11) risk of poor prognosis for CLBP. The ground assessments identified the self-selected (SSW) and optimal (OWS) walking speeds, as well as the locomotor rehabilitation index (LRI). Treadmill assessments were conducted at two different speeds (0.83 and 1.11 m s−1, SSW and OWS) to record physiomechanical parameters. Psychophysiological workloads during walking were measured via workload impulse for the session (TRIMP), determined by variations in heart rate. ResultsCLBP groups exhibited slower SSW and lower LRI compared to the CG. The TRIMP was lower in the LrG. However, both MrG and HrG exhibited a comparable overload to the CG, even while walking at a lower intensity with a psychophysical demand. SSW and OWS displayed an increased TRIMP compared to fixed speeds. ConclusionPsychosocial factors may affect SSW in people with CLBP but not among the risk strata. An unfavorable prognosis for pain could jeopardize the psychophysiological capacity to withstand walking demands.

Compensatory increase in ipsilesional supplementary motor area and premotor connectivity is associated with greater gait impairments: a personalized fMRI analysis in chronic stroke.

Balance and mobility impairments are prevalent post-stroke and a large number of survivors require walking assistance at 6 months post-stroke which diminishes their overall quality of life. Personalized interventions for gait and balance rehabilitation are crucial. Recent evidence indicates that stroke lesions in primary motor pathways, such as corticoreticular pathways (CRP) and corticospinal tract (CST), may lead to reliance on alternate motor pathways as compensation, but the current evidence lacks comprehensive knowledge about the underlying neural mechanisms. In this study, we investigate the functional connectivity (FC) changes within the motor network derived from an individualized cortical parcellation approach in 33 participants with chronic stroke compared to 17 healthy controls. The correlations between altered motor FC and gait deficits (i.e., walking speed and walking balance) were then estimated in the stroke population to understand the compensation mechanism of the motor network in motor function rehabilitation post-stroke. Our results demonstrated significant FC increases between ipsilesional medial supplementary motor area (SMA) and premotor in stroke compared to healthy controls. Furthermore, we also revealed a negative correlation between ipsilesional SMA-premotor FC and self-selected walking speed, as well as the Functional Gait Assessment (FGA) scores. The increased FC between the ipsilesional SMA and premotor regions could be a compensatory mechanism within the motor network following a stroke when the individual can presumably no longer rely on the more precise CST modulation of movements to produce a healthy walking pattern. These findings enhance our understanding of individualized motor network FC changes and their connection to gait and walking balance impairments post-stroke, improving stroke rehabilitation interventions.

Full Familiarisation Is Not Required for the Self-Paced 1 km Treadmill Walk to Predict Peak Oxygen Uptake in Phase IV Cardiac Patients.

Exercise is a recommended part of phase IV cardiovascular rehabilitation (CR). The 1 km treadmill walk test (1-KTWT) is a submaximal continuous exercise test to predict cardiorespiratory fitness in patients with cardiovascular disease. We examined physiological, metabolic and subjective responses in patients with cardiovascular disease with self-selected, unchanging walking speed for two 1-KTWTs. Fifteen men (age: 65 ± 9 yr, height: 174 ± 5 cm, body mass: 86 ± 17 kg, BMI: 28.5 ± 5.5 kg·m-2, body fat%: 27.7 ± 7.5%, 10 on beta-blockers) were recruited from phase IV CR groups in the United Kingdom. Participants established a self-selected walking speed for the 1-KTWT and performed the 1-KTWT on separate days with recording of physiological responses to predict V˙O2peak with equations. For the two 1-KTWTs, no differences existed for walking speed, mean and maximal heart rates, oxygen uptake, predicted V˙O2peak (1st 1-KTWT (range: 41-78% V˙O2peak, 95%CI, 53-65; 2nd 1-KTWT range: 43-78% V˙O2peak, 95%CI, 52-65) and rating of perceived exertion. In phase IV cardiac patients, the 1-KTWT with self-selected, unchanging walking speed can be used for V˙O2peak prediction without the need for a full familiarisation. The self-selected constant walking speed for the first 1-KTWT can be used to support nonsupervised physical activity for phase IV CR patients.

High Intensity Functional Training for People with Parkinson's & Their Care Partners: A Feasibility Study.

Various forms of exercise have proven health benefits for people with Parkinson's (pwPD) yet high intensity functional training (HIFT) has yet to be studied. The purpose of this study was to examine the feasibility, physical and psychosocial impacts of a HIFT program for pwPD and their care partners (CPs). A single group, pre-post design with assessments before, in the middle (13weeks), and after the 25-week intervention. Community fitness facility. Fourteen pwPD (10 at Hoehn Yahr Stage ≤2, 4 females) and 10 CPs (5 females) were included (mean age = 71.5 (6.1)). A 25-week HIFT program (≤49 exercise sessions, ≤75min long). Recruitment, retention, attendance, safety and exercise intensity (measured via session-Rating of Perceived Exertion (RPE)) was assessed in addition to cardiovascular endurance, lower extremity strength, walking speed, balance, exercise self-efficacy, balance confidence, social support for exercise and health-related quality of life. Descriptive data was used to describe feasibility measures. Wilcoxon signed-rank test was used to compare pre- and post-program data. Effect size, r, was calculated. Recruitment rates were ≥40% for pwPD and CPs and retention rates were 80% for pwPD and 62.5% for CPs. Average session attendance was 71.2% with 15 adverse events reported, including 7 non-injurious falls. Median session-RPE was 5 (IQR = 1) out of 10. PwPD demonstrated significant improvements in cardiovascular endurance, self-selected and fast walking speeds, balance and social support for exercise. CPs demonstrated significant improvements in cardiovascular endurance and lower extremity strength. Exercise self-efficacy, balance confidence and health-related quality of life did not significantly change for pwPD or CPs. High intensity functional training appears feasible for pwPD and their CPs and may lead to health benefits. Healthcare providers should consider HIFT as another option to engage pwPD in community-based exercise.

Dynamic Acetabular Cup Orientation during Gait: A Study of Fast- and Slow-Walking Total Hip Replacement Patients.

The dynamic orientation of total hip replacement acetabular cups during walking may vary substantially from their assumed position at surgical implantation and may vary between individuals. The scale of this effect is of interest for both pre-clinical device testing and for pre-operative surgical planning. This work aimed to evaluate (1) patient variation in dynamic cup orientation; (2) whether walking speed was a candidate proxy measure for the dynamic cup orientation; and (3) the relationships between dynamic cup orientation angles and planar pelvic angles. Pelvic movement data for patients with fast (20 patients) and slow (19 patients) self-selected walking speeds were used to calculate acetabular cup inclination and version angles through gait. For aim 1, the range and extremes of acetabular cup orientation angles were analysed for all patients. A large patient-to-patient variation was found in the ranges of both inclination angle (1° to 11°) and version angle (4° to 18°). The version angle was typically retroverted in comparison to the implantation position (greatest deviation 27°). This orientation is substantially different to the static, 0° version, simplifying assumptions in pre-clinical 'edge loading' testing. For aim 2, the cup orientation angles were compared between the fast- and slow-walking groups using statistical parametric mapping. The only significant differences observed were for cup version angle, during ~12% of the gait cycle before toe-off (p < 0.05). Therefore, self-selected walking speed, in isolation, is not a sufficient proxy measure for dynamic acetabular orientation. For aim 3, correlations were recorded between the acetabular cup orientation angles and the planar pelvic angles. The cup inclination angle during gait was strongly correlated (Spearman's coefficient -1) with pelvic obliquity alone, indicating that simple planar assessment could be used to anticipate inclination angle range. The cup version angle was correlated with both pelvic rotation and tilt (Spearman's coefficient 0.8-1), indicating that cup version cannot be predicted directly from any single pelvic movement. This complexity, along with the interaction between inclination angle and range of version angle, supports the use of computational tools to aid clinical understanding.

The Impact of Different Self-Selected Walking Speeds on Muscle Synergies in Transfemoral Amputees during Transient-State Gait

Facing above-knee amputation poses a significant hurdle due to its profound impact on walking ability. To overcome this challenge, a complex adaptation strategy is necessary at the neuromuscular level to facilitate safe movement with a prosthesis. Prior research conducted on lower-limb amputees has shown a comparable amount of intricacy exhibited by the neurological system, regardless of the level of amputation and state of walking. This research investigated the differences in muscle synergies among individuals with unilateral transfemoral amputations during walking at three different speeds of transient-state gait. Surface electromyography was recorded from eleven male transfemoral amputees’ intact limbs (TFA), and the concatenated non-negative matrix factorization technique was used to identify muscle synergy components, synergy vectors (S), and activation coefficient profiles (C). Results showed varying levels of correlation across paired-speed comparisons in TFA, categorized as poor (S1), moderate (S3 and S4), and strong (S2). Statistically significant differences were observed in all activation coefficients except C3, particularly during the stance phase. This study can assist therapists in understanding muscle coordination in TFA during unsteady gait, contributing to rehabilitation programs for balance and mobility improvement, and designing myoelectric prosthetic systems to enhance their responsiveness to trips or falls.

Optimizing exoskeleton assistance to improve walking speed and energy economy for older adults

BackgroundWalking speed and energy economy tend to decline with age. Lower-limb exoskeletons have demonstrated potential to improve either measure, but primarily in studies conducted on healthy younger adults. Promising techniques like optimization of exoskeleton assistance have yet to be tested with older populations, while speed and energy consumption have yet to be simultaneously optimized for any population.MethodsWe investigated the effectiveness of human-in-the-loop optimization of ankle exoskeletons with older adults. Ten healthy adults > 65 years of age (5 females; mean age: 72 ± 3 yrs) participated in approximately 240 min of training and optimization with tethered ankle exoskeletons on a self-paced treadmill. Multi-objective human-in-the-loop optimization was used to identify assistive ankle plantarflexion torque patterns that simultaneously improved self-selected walking speed and metabolic rate. The effects of optimized exoskeleton assistance were evaluated in separate trials.ResultsOptimized exoskeleton assistance improved walking performance for older adults. Both objectives were simultaneously improved; self-selected walking speed increased by 8% (0.10 m/s; p = 0.001) and metabolic rate decreased by 19% (p = 0.007), resulting in a 25% decrease in energetic cost of transport (p = 8e-4) compared to walking with exoskeletons applying zero torque. Compared to younger participants in studies optimizing a single objective, our participants required lower exoskeleton torques, experienced smaller improvements in energy use, and required more time for motor adaptation.ConclusionsOur results confirm that exoskeleton assistance can improve walking performance for older adults and show that multiple objectives can be simultaneously addressed through human-in-the-loop optimization.