Stair walking is associated with returning home after inpatient stroke rehabilitation in Belgium and Switzerland: a multicentric retrospective study

 Did your therapist identify EXACTLY YOUR PROBLEMS IN STAIR CLIMBING? Like specifying exactly what muscles need work according to this diagram. My hamstrings don't fire properly, something my therapists never found and obviously never fixed. Now that I have a four level condo I can slow down and climb stairs correctly instead of circumducting.

With this series of images from Nathan Nicholson I finally got the understanding that you don't just lift the foot straight up, you  engage your hamstring to pull your leg up behind you at the same time pointing your toes down(plantarflexion) to clear the lip of the step. I have to plan this all out on my own since most of my premotor cortex is dead. This currently is a very slow process.
1. Engage the hamstring
2. Point the toes down - plantarflexing 
3. Clear the step
4. Dorsiflex to lift the toe up
5. Straighten the leg 

Stair walking is associated with returning home after inpatient stroke rehabilitation in Belgium and Switzerland: a multicentric retrospective study

Odile Chevalley ^1,2, , Emmanuelle Opsommer ¹, Steven Truijen ², Grégoire Eberlé ³, Isabelle Lehmann ⁴, Katrien Van Den Keybus Déglon ³, Wim Saeys ²

PMCID: PMC12856565  PMID: 41623684

ABSTRACT

Introduction:

Identifying factors associated with discharge destination after inpatient stroke rehabilitation is important for patients and healthcare professionals. It supports discharge planning and prevents delayed discharge.

Objective:

To identify key variables from socio-demographic and clinical data associated with returning home after inpatient stroke rehabilitation, focusing on patients from three rehabilitation centers in Belgium and Switzerland.

Methods:

This multicenter retrospective study, conducted in three centers, included 1475 adult patients with stroke admitted to an inpatient rehabilitation unit between December 2012 and June 2021. A logistic regression with backward selection was used to define the model for discharge destination. The dependent variable was the discharge destination (home vs other). The independent variables were selected from the socio-demographic, medical, neurological, care pathway, and functional data and included age, gender, living arrangement, type of stroke, previous stroke, cognitive impairments, independence in grooming, eating, and stair walking.

Results:

The final model included three variables (independence in stair walking, living arrangement, and cognitive impairment). Stair walking had the strongest association with returning home. Patients who were partially (OR 5.83, 95% CI 3.67-9.26) or fully independent (OR 14.31, 95% CI 9.34-21.93) were more likely to return home than patients who were unable to walk the stairs. The results were similar for subgroups and for discharge and admission data.

Conclusion:

The study showed that independence in walking stairs is strongly associated with discharge destination. Aligned with another study, these results should be confirmed in further research.

Taking the Stairs Linked to a Boost in Longevity and Heart Health, Study Finds

 Did your competent? therapist show you this diagram and have EXACT PROTOCOLS to fix the problems you have in each part? NO? So you don't have functioning stroke medical personnel!

With this series of images from Nathan Nicholson I finally got the understanding that you don't just lift the foot straight up, you  engage your hamstring to pull your leg up behind you at the same time pointing your toes down(plantarflexion) to clear the lip of the step. I have to plan this all out on my own since most of my premotor cortex is dead. This currently is a very slow process. My therapists DID NOTHING for me on this!
1. Engage the hamstring
2. Point the toes down - plantarflexion
3. Clear the step
4. Dorsiflexion to lift the toe up
5. Straighten the leg 

Taking the Stairs Linked to a Boost in Longevity and Heart Health, Study Finds

Fact checked by Nick BlackmerFact checked by Nick Blackmer

• A new study found a link between stair climbing and a reduced risk of a cardiac event or dying from any cause.

• Experts said there isn't enough research to recommend a specific number of stairs to climb, but that any amount of stair-climbing has benefits.

• The first step to incorporating the exercise into your daily routine is to pay attention to your surroundings.

You probably already know that climbing stairs can boost fitness by burning calories and strengthening muscles, but a new analysis has found that the simple exercise may actually prolong your life.

The review, which looked at nearly 500,000 people, found a link between climbing stairs and a reduced chance of dying from any cause. Researchers also found that taking the stairs may lower the risk of cardiovascular events such as heart attack and stroke.

The findings, which haven’t been published in a peer-reviewed journal, were presented at a conference from the European Society of Cardiology in late April.

“This is the first systematic review and meta-analysis to specifically look at the association between stair climbing as a form of physical activity and cardiovascular risk,” lead study author Sophie Paddock, MD, of the University of East Anglia and Norfolk and Norwich University Hospital Foundation Trust in the United Kingdom, told Health. “It’s been well known for some time that physical inactivity is associated with a significant burden of cardiovascular disease, and many guidelines [and] policies advise us to increase our physical activity where possible.”

It’s important to remember that the study is observational and therefore doesn’t establish causation, Tamanna Singh, MD, the codirector of the Sports Cardiology Center at Cleveland Clinic, told Health. Instead, you can say that “there seems to be an association” between stair climbing and a reduced risk of dying and developing heart disease.

RichLegg / Getty Images

A Closer Look at the Study

Researchers reviewed nine studies examining the relationship between climbing stairs and cardiovascular disease and premature death. Those papers included 480,479 participants who were either in good health or had a previous history of heart attack or peripheral arterial disease. Ages ranged from 35 to 84, and about 53% were women.

The team found that people who climbed stairs as a form of exercise had a 24% lower risk of “all-cause mortality,” or dying from any cause, compared to non-stair climbers. Stair climbers also had a 39% lower chance of dying from cardiovascular disease, a category that includes coronary artery disease, heart attack, high blood pressure, and stroke. Cardiovascular disease is the leading cause of death worldwide.

Those who climbed stairs also had reduced odds of developing cardiac events such as heart attack, stroke, and heart failure.

Paddock said the study’s main limitation is that the research it reviewed relied on participants to report their climbing activity. “This may not be fully representative of their actual stair-climbing behaviors,” she said.

She also said there’s a need for more studies “that objectively measure people’s stair climbing behavior,” including the number of steps taken, and how that activity ends up impacting their health long term.

Why Stair-Climbing Boosts Health

Per Singh, the exercise’s benefits come down to one specific attribute: its vertical nature. Compared to an activity like walking on flat ground, climbing stairs is more of an “exertional challenge for your body to move itself against gravity,” she explained.

This type of movement takes up 9.6 times the amount of energy as sitting, Paddock added.

Not only does this mean that climbing stairs “improves our cardiorespiratory fitness,” Paddock said, but it can also boost other aspects of health. It “strengthens your posterior chain—glutes, hamstrings, hip flexors, calves—which improves overall mobility and musculoskeletal resilience," Singh said.

How Many Stairs Should You Climb?

According to Paddock, there isn’t enough research to recommend a specific number of flights or an intensity level to achieve the health benefits found in her study.

However, she said some studies suggest that five to six flights of stairs daily (or 50 to 60 total steps) can make an impact. A 2023 study, for example, found a link between climbing at least 50 steps daily and a 20% reduced risk of atherosclerosis, which is when plaque buildup causes arteries to harden.

Nonetheless, “any stairs are better than none,” Singh said.

She noted that taking the stairs, even in cases that “are not systematic exercise regimes,” can help reduce all-cause cardiovascular mortality.

How to Make Stair-Climbing a Habit

Incorporating stair climbing into your routine starts with simply paying attention to your surroundings. Look for stairs in homes, your workplace, parking garages, and more.

As Singh put it, “If you see stairs, climb them.”

“This type of exercise is accessible to nearly all individuals,” she added.

To stay motivated, Singh recommended creating a stair-climbing challenge at work or downloading an app that tracks the number of steps or flights climbed.

If you do create a stair-climbing routine and it eventually feels too easy, she advised continuing to “build fitness” by increasing the number of steps climbed or the frequency or duration of your workouts.

If you have mobility difficulties or lack access to stairs, try to move your body any way you can, Singh said. Similar benefits can be achieved with other types of exercise, such as swimming, biking, or rowing.

“Any physical activity is better than none,” Singh said. “Your heart really does not care what you do as long as there is a consistent practice of exercise.”

Read the original article on Health.com.

Changes in the activation and function of the ankle plantar flexor muscles due to gait retraining in chronic stroke survivors

What the hell did your doctor do with this in the past seven years? NOTHING?

Then get that doctor, the stroke department head, the president and the board of diectors fired. FOR INCOMPETENCE!

Changes in the activation and function of the ankle plantar flexor muscles due to gait retraining in chronic stroke survivors

2013, Journal of NeuroEngineering and Rehabilitation

 Brian A Knarr 1,5*, 

Trisha M Kesar 4, 

Darcy S Reisman 1,2, 

Stuart A Binder-Macleod 1,2
and Jill S Higginson 1,3

1 Biomechanics and Movement Science, University of Delaware, Newark, DE,USA.2 Department of Physical Therapy, University of Delaware, Newark, DE,USA.
3 Department of Mechanical Engineering, University of Delaware,Newark, DE, USA.
4 Department of Rehabilitation Medicine, Division of Physical Therapy, Emory University, Atlanta, GA, USA.
5 University of Delaware,126 Spencer Lab, Newark, DE 19716, USA.

Abstract

Background:
 A common goal of persons post-stroke is to regain community ambulation. The plantar flexor muscles play an important role in propulsion generation and swing initiation as previous musculoskeletal simulations have shown. The purpose of this study was to demonstrate that simulation results quantifying changes in plantar flexor activation and function in individuals post-stroke were consistent with (1) the purpose of an intervention designed to enhance plantar flexor function and (2) expected muscle function during gait based on previous literature.
Methods:
 Three-dimensional, forward dynamic simulations were created to determine the changes in model activation and function of the paretic ankle plantar flexor muscles for eight patients post-stroke after a 12-weeksFastFES gait retraining program.
Results:
 An median increase of 0.07 (Range [−0.01,0.22]) was seen in simulated activation averaged across all plantar flexors during the double support phase of gait from pre- to post-intervention. A concurrent increase in walking speed and plantar flexor induced forward center of mass acceleration by the plantar flexors was seen post-intervention for seven of the eight subject simulations. Additionally, post-training, the plantar flexors had an simulated increase in contribution to knee flexion acceleration during double support.
Conclusions:
 For the first time, muscle-actuated musculoskeletal models were used to simulate the effect of a gait retraining intervention on post-stroke muscle model predicted activation and function. The simulations showed a new pattern of simulated activation for the plantar flexor muscles after training, suggesting that the subjects activated these muscles with more appropriate timing following the intervention. Functionally, simulations calculated that the plantar flexors provided greater contribution to knee flexion acceleration after training, which is important for increasing swing phase knee flexion and foot clearance.
Keywords:
 Gait, Stroke, Musculoskeletal simulation, Plantar flexors, Muscle function
Background
3The degree of locomotor impairment post-stroke can vary greatly [1], but a majority of individuals post stroke have decreased walking speed and abnormal gait kinematics [2]. These post-stroke gait impairments are a criticaltarget of rehabilitation. The use of treadmills has gained popularity as an intervention for gait retraining post-stroke [3-6]. Recent studies have investigated combining treadmill walking with more targeted rehabilitation methods such as functional electrical stimulation (FES) [7].In particular, impairment of the plantar flexors, typical of stroke gait, has been the focus of recent rehabilitation approaches [8,9] because of the importance of both foot clearance and forward propulsion in post stroke gait function [10].It has been shown that functional electrical stimulation of the plantar flexors during preswing, along with the paretic ankle dorsiflexors during swing, provided additional gait benefits including increased swing phase knee flexion, plantar flexion at toe-off, and forward
* Correspondence: bknarr@udel.edu
1 Biomechanics and Movement Science, University of Delaware, Newark, DE,USA
5 University of Delaware, 126 Spencer Lab, Newark, DE 19716, USAFull list of author information is available at the end of the article
JNER
 JOURNAL OF NEUROENGINEERINGAND REHABILITATION
© 2013 Knarr et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the CreativeCommons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

 

Changes in the activation and function of the ankle plantar flexor muscles due to gait retraining in chronic stroke survivors

My conclusions on this is that it is useless, just an analysis of what is going on and no protocol created and publicly published for survivors to find. Nothing that will help us get 100% recovered. Nothing on how to activate plantar muscles better. 

Changes in the activation and function of the ankle plantar flexor muscles due to gait retraining in chronic stroke survivors

  Brian A Knarr 1,5*
 Trisha M Kesar 4
 Darcy S Reisman 1,2
 Stuart A Binder-Macleod 1,2
and Jill S Higginson 1,3
 Correspondence: bknarr@udel.edu
1 Biomechanics and Movement Science, University of Delaware, Newark, DE,USA
5 University of Delaware, 126 Spencer Lab, Newark, DE 19716, USA Full list of author information is available at the end of the article

Abstract

Background:
 A common goal of persons post-stroke is to regain community ambulation. The plantar flexor muscles play an important role in propulsion generation and swing initiation as previous musculoskeletal simulations have shown. The purpose of this study was to demonstrate that simulation results quantifying changes in plantar flexor activation and function in individuals post-stroke were consistent with (1) the purpose of an intervention designed to enhance plantar flexor function and (2) expected muscle function during gait based on previous literature.
Methods:
 Three-dimensional, forward dynamic simulations were created to determine the changes in model activation and function of the paretic ankle plantar flexor muscles for eight patients post-stroke after a 12-weeksFastFES gait retraining program.
Results:
 An median increase of 0.07 (Range [0.01,0.22]) was seen in simulated activation averaged across all plantar flexors during the double support phase of gait from pre- to post-intervention. A concurrent increase in walking speed and plantar flexor induced forward center of mass acceleration by the plantar flexors was seen post intervention for seven of the eight subject simulations. Additionally, post-training, the plantar flexors had an simulated increase in contribution to knee flexion acceleration during double support.
Conclusions:
 For the first time, muscle-actuated musculoskeletal models were used to simulate the effect of a gait retraining intervention on post-stroke muscle model predicted activation and function. The simulations showed a new pattern of simulated activation for the plantar flexor muscles after training, suggesting that the subjects activated these muscles with more appropriate timing following the intervention(Where is that intervention located/described?). Functionally, simulations calculated that the plantar flexors provided greater contribution to knee flexion acceleration after training, which is important for increasing swing phase knee flexion and foot clearance.

Functional Electrical Stimulation of Ankle Plantarflexor and Dorsiflexor Muscles: Effects on Poststroke Gait

In the 11 years since this came out, has a stroke protocol been published AND distributed  to ALL 10 million yearly stroke survivors? If not, THEN THERE IS COMPLETE FUCKING INCOMPETENCY IN TENS OF THOUSANDS OF STROKE DOCTORS AND THERAPISTS. Do you prefer your incompetency NOT KNOWING OR NOT DOING? Your Hobson's choice. Until we start writing and updating protocols stroke rehab will never move forward. Guidelines are useless because they leave leeway for the survivor to be blamed for not recovering. This is so obvious, IS EVERYONE IN STROKE LEADERSHIP COMPLETELY STUPID?

Functional Electrical Stimulation of Ankle Plantarflexor and Dorsiflexor Muscles: Effects on Poststroke Gait

 Stroke
. 2009 December ; 40(12): 3821–3827. doi:10.1161/STROKEAHA.109.5603
Trisha M. Kesar, PT, PhD 1,
Ramu Perumal, PhD 2,
Darcy S. Reisman, PT, PhD 1,2,
 AngelaJancosko, PT 2,
Katherine S. Rudolph, PT, PhD 1,2,
Jill S Higginson, PhD 2,3, and
Stuart A.Binder-Macleod, PT, PhD 1,2
1 Department of Physical Therapy, University of Delaware, Newark, DE
2 Graduate Program in Biomechanics and Movement Science, University of Delaware, Newark, DE
3 Department of Mechanical Engineering, University of Delaware, Newark, DE

 Abstract

Background and Purpose—
Functional electrical stimulation (FES) is a popular post-stroke gait rehabilitation intervention. Although stroke causes multi-joint gait deficits, FES is commonly used only for the correction of swing phase foot drop. Ankle plantar flexor muscles play an important role during gait. The aim of the current study is to test the immediate effects of delivering FES to both ankle plantar flexors and dorsiflexors on post-stroke gait.
Methods—
Gait analysis was performed as subjects (N=13) with chronic post-stroke hemiparesis walked at their self-selected walking speeds during walking with and without FES.
Results—
Compared to delivering FES to only the ankle dorsiflexor muscles during the swing phase,delivering FES to both the paretic ankle plantarflexors during terminal stance and dorsiflexors during swing phase provided the advantage of greater swing phase knee flexion, greater ankle plantar flexion angle at toe-off, and greater forward propulsion. Although FES of both the dorsi- and plantar flexor muscles improved swing phase ankle dorsiflexion compared to no FES, the improvement was less than that observed by stimulating the dorsiflexors alone, suggesting the need to further optimize stimulation parameters and timing for the dorsiflexor muscles during gait.
Conclusions—
In contrast to the typical FES approach of only stimulating ankle dorsiflexor muscles during the swing phase, delivering FES to both the plantar- and dorsiflexor muscles can help to correct post-stroke gait deficits at multiple joints (ankle and knee) during both the swing and stance phases of gait. Our study shows the feasibility and advantages of stimulating the ankle plantar flexors during FES for post-stroke gait.
 

Functional Electrical Stimulation of Ankle Plantarflexor and Dorsiflexor Muscles: Effects on Poststroke Gait

We don't need weasel words like 'can help'. We need definitive EXACT STROKE PROTOCOLS. This is useless. 

Functional Electrical Stimulation of Ankle Plantarflexor and Dorsiflexor Muscles: Effects on Poststroke Gait

risha M. Kesar, PT, PhD
1,
Ramu Perumal, PhD
2,
Darcy S. Reisman, PT, PhD
1,2,
 AngelaJancosko, PT
2,
Katherine S. Rudolph, PT, PhD
1,2,
Jill S Higginson, PhD
2,3, and
Stuart A.Binder-Macleod, PT, PhD
1,2
1
 Department of Physical Therapy, University of Delaware, Newark, DE
2
 Graduate Program in Biomechanics and Movement Science, University of Delaware, Newark, DE
3
 Department of Mechanical Engineering, University of Delaware, Newark, DE

 

Abstract

Background and Purpose—

Functional electrical stimulation (FES) is a popular post-stroke gaitrehabilitation intervention. Although stroke causes multi-joint gait deficits, FES is commonly used only for the correction of swing phase foot drop. Ankle plantarflexor muscles play an important roleduring gait. The aim of the current study is to test the immediate effects of delivering FES to bothankle plantarflexors and dorsiflexors on post-stroke gait.
Methods—
Gait analysis was performed as subjects (N=13) with chronic post-stroke hemiparesiswalked at their self-selected walking speeds during walking with and without FES.
Results—
Compared to delivering FES to only the ankle dorsiflexor muscles during the swing phase,delivering FES to both the paretic ankle plantarflexors during terminal stance and dorsiflexors duringswing phase provided the advantage of greater swing phase knee flexion, greater ankle plantarflexionangle at toe-off, and greater forward propulsion. Although FES of both the dorsi- and plantar-flexor muscles improved swing phase ankle dorsiflexion compared to noFES, the improvement was lessthan that observed by stimulating the dorsiflexors alone, suggesting the need to further optimizestimulation parameters and timing for the dorsiflexor muscles during gait.
Conclusions—
In contrast to the typical FES approach of only stimulating ankle dorsiflexor muscles during the swing phase, delivering FES to both the plantar- and dorsi-flexor muscles can help to correct post-stroke gait deficits at multiple joints (ankle and knee) during both the swing and stance phases of gait. Our study shows the feasibility and advantages of stimulating the ankle plantarflexors during FES for post-stroke gait.

Reducing the metabolic cost of walking with an ankle exoskeleton: interaction between actuation timing and power

Stroke use and clinical testing needs a followup on this. Assisting dorsiflexion and plantatflexion(push off) would be a massive win for those survivors with drop foot. 11 years later and I still have no push off.
http://jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-017-0235-0

• Samuel Galle†Email authorView ORCID ID profile,
• Philippe Malcolm†,
• Steven Hartley Collins and
• Dirk De Clercq

†Contributed equally

Journal of NeuroEngineering and Rehabilitation201714:35

DOI: 10.1186/s12984-017-0235-0

©  The Author(s). 2017

Received: 10 September 2016

Accepted: 17 March 2017

Published: 27 April 2017

Abstract

Background

Powered ankle-foot exoskeletons can reduce the metabolic cost of human walking to below normal levels, but optimal assistance properties remain unclear. The purpose of this study was to test the effects of different assistance timing and power characteristics in an experiment with a tethered ankle-foot exoskeleton.

Methods

Ten healthy female subjects walked on a treadmill with bilateral ankle-foot exoskeletons in 10 different assistance conditions. Artificial pneumatic muscles assisted plantarflexion during ankle push-off using one of four actuation onset timings (36, 42, 48 and 54% of the stride) and three power levels (average positive exoskeleton power over a stride, summed for both legs, of 0.2, 0.4 and 0.5 W∙kg⁻¹). We compared metabolic rate, kinematics and electromyography (EMG) between conditions.

Results

Optimal assistance was achieved with an onset of 42% stride and average power of 0.4 W∙kg⁻¹, leading to 21% reduction in metabolic cost compared to walking with the exoskeleton deactivated and 12% reduction compared to normal walking without the exoskeleton. With suboptimal timing or power, the exoskeleton still reduced metabolic cost, but substantially less so. The relationship between timing, power and metabolic rate was well-characterized by a two-dimensional quadratic function. The assistive mechanisms leading to these improvements included reducing muscular activity in the ankle plantarflexors and assisting leg swing initiation.

Conclusions

These results emphasize the importance of optimizing exoskeleton actuation properties when assisting or augmenting human locomotion. Our optimal assistance onset timing and average power levels could be used for other exoskeletons to improve assistance and resulting benefits.

Keywords

Human locomotion Augmentation Lower-limb exoskeletons Metabolic cost Optimal assistance

Background

Walking is the most frequent means of human locomotion [1]. While humans use many strategies to reduce energy expenditure [2], walking still requires a considerable amount of metabolic energy, sometimes referred to as the ‘metabolic cost’ of walking. Assisting the ankle joint with an exoskeleton can reduce the metabolic cost of walking to below the cost of normal walking [3, 4, 5, 6]. This shows that it is possible to reduce metabolic cost through robotic assistance.

Reductions in the metabolic cost of walking with ankle-foot exoskeletons result from two competing factors. A benefit can be derived from the exoskeleton when it acts to assist gait, expressed as the difference between powered exoskeleton¹ walking and walking in zero-work mode¹. However, wearing the exoskeleton in zero-work mode typically results in a metabolic penalty, expressed as the difference between normal walking¹ without an exoskeleton and walking in zero-work mode. Some full-body exoskeletons have resulted in large metabolic penalties (e.g. [7]) while lightweight ankle-foot exoskeletons have resulted in penalties of less than 3% for active autonomous¹ exoskeletons [4] and even close to zero for passive autonomous¹ exoskeletons [5]. Reducing the penalty of wearing an exoskeleton in zero-work mode is mainly a design challenge, while increasing the difference between the zero-work condition and powered exoskeleton conditions is mainly a biomechanics challenge.

In order to solve the latter human-exoskeleton interaction challenge, optimal assistance properties (e.g. actuation timing, assistance magnitude, etc.) are crucial to further reduce the metabolic energy cost of walking. Malcolm et al. [3] showed that the timing of exoskeleton actuation onset (referred to as actuation timing) is an important exoskeleton property that influences the metabolic cost of walking with active exoskeletons. They found a convex landscape in metabolic cost versus actuation timing with an optimum around 40% of the stride. Studies that have found the highest reductions in metabolic energy cost have also used an actuation timing around 40% of the stride [4, 6].

Of course, actuation timing is not the only determinant of metabolic cost when walking with ankle-exoskeleton assistance. Assistance magnitude also seems to have a strong effect [8, 9]. The average positive mechanical exoskeleton power per stride summed for both ankles (referred to here as exoskeleton power) can be as high as 0.38 W∙kg⁻¹ resulting in reductions in net metabolic cost of between 10 and 22% for powered exoskeleton conditions compared to zero-work conditions [3, 4, 6, 8, 10, 11, 12]. However, comparing these studies does not result in a clear relationship between exoskeleton power magnitude and metabolic cost, likely because many factors differ between studies (e.g. design, exoskeleton mass, actuation profile, etc.), confounding comparisons. The simplest walking model [13] would suggest that increasing exoskeleton power will reduce the mechanical energy requirements for walking until subjects walk with zero metabolic cost. Indeed, a recent study, in which both ankle and hip joints were assisted with a soft exo-suit [8] indicated that metabolic energy cost reduces linearly with increasing exoskeleton assistance magnitude, similar to some findings with active prostheses [9]. On the other hand, a study on unilateral exoskeleton assistance suggested an exponential relationship between device power and metabolic cost [14]. Experiments and simulation studies with exoskeletons have similarly suggested that under some conditions “more is not always better” [5, 15, 16]. Interpretations have been made more difficult by the limited range of attainable levels of exoskeleton power, which has often been between 50 and 80% of biological ankle power [4, 10, 11].

In order to study if and when the reduction in the metabolic cost of walking begins to level-off with increasing exoskeleton power during bilateral exoskeleton assistance, it seems necessary to deliver more power than in current studies. To identify the influence of exoskeleton power magnitude on the metabolic cost of walking, as well as the interaction with actuation timing, there is a need for a parametric study of actuation timing and exoskeleton power over a larger range. A study of both actuation characteristics is also expected to contribute to an improved understanding of the assistive mechanisms of ankle-foot exoskeletons. Several studies have indicated that other joints besides the ankle joint are involved in the reduction in metabolic cost experienced when using an ankle-foot exoskeleton [3, 4, 5, 8, 12, 17, 18] but the exact mechanisms are unclear. Exploring different assistance parameters over a broad range would help to identify the relationship between biomechanical changes and the resulting changes in metabolic cost.

The overall goal of this study was to characterize the relationship between ankle exoskeleton power, actuation timing, and metabolic cost during walking over a broad range. We used a tethered and powered plantarflexion-assisting exoskeleton to vary actuation onset timing and average exoskeleton power independently and over a broad range and studied the influence of these characteristics on the metabolic energy cost of walking. We expected a second-order effect of actuation timing on metabolic energy cost [3] and explored several candidate relationships between exoskeleton power and metabolic energy cost to evaluate the interaction between timing, power and metabolic cost. A secondary goal was to use the best relationship to define optimal assistance parameters. Finally, we analyzed muscle activation, exoskeleton kinetics and walking kinematics that describe the neuromechanical interaction between the exoskeleton and the human, with the goal of explaining the reduction in metabolic cost and improving our understanding of human-exoskeleton interaction.

More at link.

A neuromechanics-based powered ankle exoskeleton to assist walking post-stroke: a feasibility study

Will your doctor use this or stick to static AFOs?
http://www.jneuroengrehab.com/content/12/1/23/abstract

Kota Z Takahashi^1*, Michael D Lewek² and Gregory S Sawicki^1*

• * Corresponding authors: Kota Z Takahashi ktakaha@ncsu.edu - Gregory S Sawicki gsawicki@email.unc.edu

Author Affiliations

For all author emails, please log on.

Journal of NeuroEngineering and Rehabilitation 2015, 12:23  doi:10.1186/s12984-015-0015-7
Published: 25 February 2015

Abstract

Background

In persons post-stroke, diminished ankle joint function can contribute to inadequate gait propulsion. To target paretic ankle impairments, we developed a neuromechanics-based powered ankle exoskeleton. Specifically, this exoskeleton supplies plantarflexion assistance that is proportional to the user’s paretic soleus electromyography (EMG) amplitude only during a phase of gait when the stance limb is subjected to an anteriorly directed ground reaction force (GRF). The purpose of this feasibility study was to examine the short-term effects of the powered ankle exoskeleton on the mechanics and energetics of gait.

Methods

Five subjects with stroke walked with a powered ankle exoskeleton on the paretic limb for three 5 minute sessions. We analyzed the peak paretic ankle plantarflexion moment, paretic ankle positive work, symmetry of GRF propulsion impulse, and net metabolic power.

Results

The exoskeleton increased the paretic plantarflexion moment by 16% during the powered walking trials relative to unassisted walking condition (p < .05). Despite this enhanced paretic ankle moment, there was no significant increase in paretic ankle positive work, or changes in any other mechanical variables with the powered assistance. The exoskeleton assistance appeared to reduce the net metabolic power gradually with each 5 minute repetition, though no statistical significance was found. In three of the subjects, the paretic soleus activation during the propulsion phase of stance was reduced during the powered assistance compared to unassisted walking (35% reduction in the integrated EMG amplitude during the third powered session).

Conclusions

This feasibility study demonstrated that the exoskeleton can enhance paretic ankle moment. Future studies with greater sample size and prolonged sessions are warranted to evaluate the effects of the powered ankle exoskeleton on overall gait outcomes in persons post-stroke.

Stroke therapy at St. Peters cathedral during Latin high mass

Sacrareligious I know but not knowing any Latin I didn't want to waste any time that could be used doing therapy. I spent the whole service passively flexing and extending the fingers on my left hand. The one time we all got down on the kneelers I used that time to dorsiflex and plantarflex my left foot rubbing against the floor.
Looking over the crowds in St. Peters square.