The Stepping Threshold Test for assessing reactive balance discriminates between older adult fallers and non-fallers.

Introduction: The ability to respond effectively to external perturbations is crucial for avoiding falls. The Stepping Threshold Test (STT) has been developed to assess this reactive balance, but its ability to discriminate between fallers and non-fallers is still unsubstantiated. This study aimed to evaluate the discriminant validity of the STT in distinguishing fallers and non-fallers and its convergent validity.

A full-body motion capture gait dataset of 138 able-bodied adults across the life span and 50 stroke survivors.

This reference dataset contains biomechanical data of 138 able-bodied adults (21-86 years) and 50 stroke survivors walking bare-footed at their preferred speed. It is unique due to its size, and population, including adults across the life-span and over 70 years, as well as stroke survivors. Full-body kinematics (PiG-model), kinetics and muscle activity of 14 back and lower limbs muscles was collected with a Vicon motion capture system, ground-embedded force plates, and a synchronized surface EMG system.

Age- and sex-related differences in trunk kinematics during walking in able-bodied adults.

Introduction: Trunk motion during walking acts as a biomarker for decreased mobility and can differ between sexes. Knowing how age and sex affect trunk motion and energy conservation can help clinicians decide when and in whom to intervene with physiotherapy to prolong functional mobility.

Methods: A large sample of 138 able-bodied males and females in the age-categories 20-39 years, 40-59 years, 60-69 years, 70-79 years, and 80-89 years received a full-body 3D gait analysis.

Rollator usage lets young individuals switch movement strategies in sit-to-stand and stand-to-sit tasks.

The transitions between sitting and standing have a high physical and coordination demand, frequently causing falls in older individuals. Rollators, or four-wheeled walkers, are often prescribed to reduce lower-limb load and to improve balance but have been found a fall risk. This study investigated how rollator support affects sit-to-stand and stand-to-sit movements.

Aging in 10 Minutes: Do Age Simulation Suits Mimic Physical Decline in Old Age? Comparing Experimental Data with Established Reference Data.

Introduction: Age simulation suits are increasingly used in health care education. However, empirical evidence that quantifies the simulated performance losses in established geriatric tests and compares those declines with reference data of older adults is scarce.

Methods: In a standardized lab setting, we compared performance of  = 61 participants (46 middle-aged, 15 young adults) with and without age simulation suit, for example in the Timed Up and Go Test (+dual task), Short Physical Performance Battery, grip strength, and 30-Second-Chair- Standing Test.

Feasibility, effectiveness and acceptability of two perturbation-based treadmill training protocols to improve reactive balance in fall-prone older adults (FEATURE): protocol for a pilot randomised controlled trial.

Introduction: Perturbation-based balance training (PBT) targets the mechanism of falls (eg, slipping, tripping) to specifically train the recovery actions needed to avoid a fall. This task-specific training has shown great promise as an effective and efficient intervention for fall prevention in older adults. However, knowledge about the dose-response relationship of PBT, as well as its feasibility and acceptability in older adults with increased risk of falling is still limited.

Effects of a soft robotic exosuit on the quality and speed of overground walking depends on walking ability after stroke.

Background: Soft robotic exosuits can provide partial dorsiflexor and plantarflexor support in parallel with paretic muscles to improve poststroke walking capacity. Previous results indicate that baseline walking ability may impact a user's ability to leverage the exosuit assistance, while the effects on continuous walking, walking stability, and muscle slacking have not been evaluated. Here we evaluated the effects of a portable ankle exosuit during continuous comfortable overground walking in 19 individuals with chronic hemiparesis.

Contribution of arm movements to balance recovery after tripping in older adults.

Falls are common in daily life, often caused by trips and slips and, particularly in older adults, with serious consequences. Although arm movements play an important role in balance control, there is limited research into the role of arm movements during balance recovery after tripping in older adults. We investigated how older adults use their arms to recover from a trip and the difference in the effects of arm movements between fallers (n = 5) and non-fallers (n = 11).

Functional assessment of stretch hyperreflexia in children with cerebral palsy using treadmill perturbations.

Background: As hyperactive muscle stretch reflexes hinder movement in patients with central nervous system disorders, they are a common target of treatment. To improve treatment evaluation, hyperactive reflexes should be assessed during activities as walking rather than passively. This study systematically explores the feasibility, reliability and validity of sudden treadmill perturbations to evoke and quantify calf muscle stretch reflexes during walking in children with neurological disorders.

Decline in gait propulsion in older adults over age decades.

Background: Despite strong evidence that walking speed and forward propulsion decline with increasing age, their relationship is still poorly understood. While changes in the ankle and hip mechanics have been described, few studies have reported the effect of ageing on the whole leg's contribution to propulsion.

Research Question: The aim of this study was to investigate age-related changes in the work performed by the leg on the center of mass (COM) push-off power during walking in adults aged 20-86 years.

Applying Stretch to Evoke Hyperreflexia in Spasticity Testing: Velocity vs. Acceleration.

In neurological diseases, muscles often become hyper-resistant to stretch due to hyperreflexia, an exaggerated stretch reflex response that is considered to primarily depend on the muscle's stretch velocity. However, there is still limited understanding of how different biomechanical triggers applied during clinical tests evoke these reflex responses. We examined the effect of imposing a rotation with increasing velocity vs.

Relationship Between Muscular Activity and Assistance Magnitude for a Myoelectric Model Based Controlled Exosuit.

The growing field of soft wearable exosuits, is gradually gaining terrain and proposing new complementary solutions in assistive technology, with several advantages in terms of portability, kinematic transparency, ergonomics, and metabolic efficiency. Those are palatable benefits that can be exploited in several applications, ranging from strength and resistance augmentation in industrial scenarios, to assistance or rehabilitation for people with motor impairments. To be effective, however, an exosuit needs to synergistically work with the human and matching specific requirements in terms of both movements kinematics and dynamics: an accurate and timely intention-detection strategy is the paramount aspect which assume a fundamental importance for acceptance and usability of such technology.

Slow but Steady: Similar Sit-to-Stand Balance at Seat-Off in Older vs. Younger Adults.

Many older adults suffer injuries due to falls as the ability to safely move between sitting and standing degrades. Unfortunately, while existing measures describe sit-to-stand (STS) performance, they do not directly measure the conditions for balance. To gain insight into the effect of age on STS balance, we analyzed how far 8 older and 10 young adults strayed from a state of static balance and how well each group maintained dynamic balance.

A hinge-free, non-restrictive, lightweight tethered exosuit for knee extension assistance during walking.

In individuals with motor impairments such as those post-stroke or with cerebral palsy, the function of the knee extensors may be affected during walking, resulting in decreased mobility. We have designed a lightweight, hinge-free wearable robot combining soft textile exosuit components with integrated rigid components, which assists knee extension when needed but is otherwise highly transparent to the wearer. The exosuit can apply a wide range of assistance profiles using a flexible multi-point reference trajectory generator.

How to measure responses of the knee to lateral perturbations during gait? A proof-of-principle for quantification of knee instability.

Knee instability is a major problem in patients with anterior cruciate ligament injury or knee osteoarthritis. A valid and clinically meaningful measure for functional knee instability is lacking. The concept of the gait sensitivity norm, the normalized perturbation response of a walking system to external perturbations, could be a sensible way to quantify knee instability.

A soft robotic exosuit improves walking in patients after stroke.

Stroke-induced hemiparetic gait is characteristically slow and metabolically expensive. Passive assistive devices such as ankle-foot orthoses are often prescribed to increase function and independence after stroke; however, walking remains highly impaired despite-and perhaps because of-their use. We sought to determine whether a soft wearable robot (exosuit) designed to supplement the paretic limb's residual ability to generate both forward propulsion and ground clearance could facilitate more normal walking after stroke.

Motorized versus manual instrumented spasticity assessment in children with cerebral palsy.

Aim: We compared the outcomes of manual and motorized instrumented ankle spasticity assessments in children with cerebral palsy (CP).

Method: Ten children with spastic CP (three males, seven females; mean age 11y [standard deviation 3y], range 6-14y; Gross Motor Function Classification System levels I-III) were included. During motorized assessments, fast (100°/s) rotations were imposed around the ankle joint by a motor-driven footplate; during manual assessments, rotations of comparable speed were applied by a therapist using a foot orthotic.

Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e.

Self-paced versus fixed speed walking and the effect of virtual reality in children with cerebral palsy.

While feedback-controlled treadmills with a virtual reality could potentially offer advantages for clinical gait analysis and training, the effect of self-paced walking and the virtual environment on the gait pattern of children and different patient groups remains unknown. This study examined the effect of self-paced (SP) versus fixed speed (FS) walking and of walking with and without a virtual reality (VR) in 11 typically developing (TD) children and nine children with cerebral palsy (CP). We found that subjects walked in SP mode with twice as much between-stride walking speed variability (p<0.

Kinetic comparison of walking on a treadmill versus over ground in children with cerebral palsy.

Kinetic outcomes are an essential part of clinical gait analysis, and can be collected for many consecutive strides using instrumented treadmills. However, the validity of treadmill kinetic outcomes has not been demonstrated for children with cerebral palsy (CP). In this study we compared ground reaction forces (GRF), center of pressure, and hip, knee and ankle moments, powers and work, between overground (OG) and self-paced treadmill (TM) walking for 11 typically developing (TD) children and 9 children with spastic CP.

The validity and reliability of modelled neural and tissue properties of the ankle muscles in children with cerebral palsy.

Spastic cerebral palsy (CP) is characterized by increased joint resistance, caused by a mix of increased tissue stiffness, as well as involuntary reflex and background muscle activity. These properties can be quantified using a neuromechanical model of the musculoskeletal complex and instrumented assessment. The construct validity of the neuromechanical parameters was examined (i.

Overground versus self-paced treadmill walking in a virtual environment in children with cerebral palsy.

Treadmill walking offers several advantages for clinical gait analysis and gait training, but may affect gait parameters. We compared walking on a self-paced treadmill in a virtual environment (TM+) with overground walking in a conventional gait lab (CGL), and with natural walking (NW) outside a lab environment on a GaitRite measurement mat, for 11 typically developing (TD) children and 9 children with cerebral palsy (CP). Spatiotemporal parameters and subjective scores on similarity to normal walking were compared between all three conditions, while kinematic parameters and Gait and Motion Analysis Profile Scores (GPS and MAP) were compared between CGL and TM+.

Sensitivity of trunk variability and stability measures to balance impairments induced by galvanic vestibular stimulation during gait.

For targeted prevention of falls, it is necessary to identify individuals with balance impairments. To test the sensitivity of measures of variability, local stability and orbital stability of trunk kinematics to balance impairments during gait, we used galvanic vestibular stimulation (GVS) to impair balance in 12 young adults while walking on a treadmill at different speeds. Inertial sensors were used to measure trunk accelerations, from which variability in the medio-lateral direction and local and orbital stability were calculated.

Sensitivity of local dynamic stability of over-ground walking to balance impairment due to galvanic vestibular stimulation.

Impaired balance control during gait can be detected by local dynamic stability measures. For clinical applications, the use of a treadmill may be limiting. Therefore, the aim of this study was to test sensitivity of these stability measures collected during short episodes of over-ground walking by comparing normal to impaired balance control.