Exoscore: A Design Tool to Evaluate Factors Associated With Technology Acceptance of Soft Lower Limb Exosuits by Older Adults.

OBJECTIVE: This pilot study proposed and performs initial testing with Exoscore, a design evaluation tool to assess factors related to acceptance of exoskeleton by older adults, during the technology development and testing phases. BACKGROUND: As longevity increases and our aging population continues to grow, assistive technologies such as exosuits and exoskeletons can provide enhanced quality of life and independence. Exoscore is a design and prototype stage evaluation method to assess factors related to perceptions of the technology, the aim being to optimize technology acceptance. METHOD: In this pilot study, we applied the three-phase Exoscore tool during testing with 11 older adults. The aims were to explore the feasibility and face validity of applying the design evaluation tool during user testing of a prototype soft lower limb exoskeleton. RESULTS: The Exoscore method is presented as part of an iterative design evaluation process. The method was applied during an exoskeleton research and development project. The data revealed the aspects of the concept design that rated favorably with the users and the aspects of the design that required more attention to improve their potential acceptance when deployed as finished products. CONCLUSION: Exoscore was effectively applied to three phases of evaluation during a testing session of a soft exoskeleton. Future exoskeleton development can benefit from the application of this design evaluation tool. APPLICATION: This study reveals how the introduction of Exoscore to exoskeleton development will be advantageous when assessing technology acceptance of exoskeletons by older adults.

Average torsion axis location of athletic movements: subject specific or movement specific?

Foot torsion angles have previously been studied for different athletic movements. Sport shoes often contain a torsion element even though the location of the rotation axis of the foot is unknown. Therefore, the purpose of this study was to quantify the torsion axis location and determine if the location is influenced by the movement or the subject. The torsion axis location was calculated using a modified finite helical axis approach, which allowed the calculation of the rotation axis between the forefoot and the rearfoot without the influence of forefoot flexion. The torsion axis location during the lateral jab was 9.72 mm below and 26.96 mm lateral to a marker located at the posterior, central heel, whereas the shuffle cut resulted in an axis location of 9.59 mm below and 26.19 mm lateral to the reference marker. There was no significant difference for the average axis location between movements. There was, however, a significant difference for the location between subjects, indicating a subject specificity of the torsion axis. The results of the current study are the first to quantify the torsion axis location of the human foot during athletic movements.

Health-enhancing physical activity interventions in non-ambulatory people with severe motor impairments - a scoping review.

PURPOSE: Non-ambulatory people with severe motor impairments due to chronic neurological diagnoses are forced into a sedentary lifestyle. The purpose of this scoping review was to understand the type and amount of physical activity interventions performed in this population as well as their effect. METHODS: PubMed, Cochran and CINAHL Complete were systematically searched for articles describing physical activity interventions in people with a chronic, stable central nervous system lesion. The outcome measures needed to include physiological or psychological variables, measures of general health or quality of life. RESULTS: Of the initial 7554 articles, 34 were included after the title, abstract, and full-text screening. Only six studies were designed as randomized-controlled trials. Most interventions were supported by technologies, mainly functional electrical stimulation (cycling or rowing). The duration of the intervention ranged from four to 52 weeks. Endurance and strength training interventions (and a combination of both) were performed and over 70% of studies resulted in health improvements. CONCLUSIONS: Non-ambulatory people with severe motor impairments may benefit from physical activity interventions. However, the number of studies and their comparability is very limited. This indicates the need for future research with standard measures to develop evidence-based, specific recommendations for physical activity in this population.Key messagesPhysical activity interventions can have health benefits in non-ambulatory people with severe motor impairments.Even simple, low-tech interventions allow for health-enhancing training.

Biomechanical comparison of walking with a new, wearable rehabilitation training device to Nordic walking and regular walking in people with chronic low back pain.

Physical activity, particularly walking, is commonly used for the treatment of diseases such as low back pain. In this study, the effects of walking wearing the new ToneFit Reha training belt (TFR) were compared to both Nordic walking and regular walking. The TFR is intended to intensify the effects of walking through the integration of two adjustable resistance handles. Ten patients with low back pain performed regular walking, Nordic walking, and walking with the TFR in a movement laboratory. The kinematics of the trunk, upper extremities, and lower extremities were measured, and the activity of the trunk and upper extremity muscles recorded. Data were analyzed by repeated-measures ANOVA and paired t-test. Kinematics indicated that walking with the TFR introduces instability that was mitigated by a delayed peak trunk rotation (peak at 63.3% gait cycle, vs. 52.8% in walking (p = .001) and 51.0% in NW (p = .007)). Upper extremity kinematics (constrained elbow flexion, high peak shoulder abduction) showed movement patterns that need to be considered when training over a longer period. Increased muscle activity was observed especially for upper extremity muscles, when training with TFR. Overall, walking with the TFR was found to be a suitable therapy for use in a rehabilitation setting.

Hip and trunk kinematics during reaching on a mobile and stable seat.

Reaching movements are often used to assess selective trunk control in people with neurological conditions. Also, it is known that reaching performance after stroke is increased through training on a mobile seat compared to conventional physical therapy. However, the effect of a mobile seat on joint kinematics has not yet been investigated. This study aimed to quantify differences in the range of motion of the hip and trunk during reaching exercises on a mobile and stable sitting surface. Fifteen healthy participants performed reaching beyond arm's length on a mobile and a stable seat in four different directions: ipsilateral, anterior, contralateral, and contralateral diagonal. Biomechanical data were collected, including kinematics of the hip and trunk, and surface electromyography of the trunk muscles. The mobile sitting surface led to a higher range of motion in the trunk and the hip in the frontal and sagittal plane, but not in the rotational plane. Differences between reaching directions were found in all joint directions, except that of trunk flexion. Hence, movement patterns of the hip and trunk differ during reaching on different sitting surfaces and in different directions. A larger range of motion in the frontal or sagittal plane while training on the mobile seat provides added neuromuscular stimuli to the trunk muscles (= a higher demand on trunk muscles), which could result in more efficient training and therefore, increased trunk control after stroke. However, this has to be investigated in a future study with people after stroke.

The Effect on Muscle Activity of Reaching Beyond Arm's Length on a Mobile Seat: A Pilot Study for Trunk Control Training for People After Stroke.

Objective: This pilot study compared muscle activity during lateral reaching tasks between mobile and stable sitting using a novel therapy chair in people after stroke and healthy controls. Design: Observational pilot study. Setting: This study was conducted in a rehabilitation center for people after stroke and at the university's movement laboratory for healthy participants. Participants: A total of eleven people after stroke and fifteen healthy people (N=26) took part. Interventions: Lateral reaching exercises to the ipsilateral and contralateral sides were performed on a mobile and a stable seat. Main Outcome Measure: Muscular activity of the multifidus, erector spinae and external oblique was measured bilaterally. A within-subject linear mixed model was applied to analyze the effects of seat condition, task, muscle side, and group. Results: A seat condition effect was found for the multifidus and external oblique that was dependent on the muscle side and task. During ipsilateral reaching, the activity of the multifidi decreased for people after stroke on the mobile seat, while increasing for healthy participants. The erector spinae showed no condition effect. Decreased activity of the external oblique was found for both groups on the mobile seat. Conclusions: Mobile sitting influences muscular activity. However, these preliminary results should be further investigated in order to generate recommendations for rehabilitation.

Facilitators and barriers to health enhancing physical activity in individuals with severe functional limitations after stroke: A qualitative study.

Background: Patients with chronic conditions are less physically active than the general population despite knowledge of positive effects on physical and mental health. There is a variety of reasons preventing people with disabilities from achieving levels of physical activities resulting in health benefits. However, less is known about potential facilitators and barriers for physical activity (PA) in people with severe movement impairments. The aim of this study was to identify obstacles and facilitators of PA in individuals with severe disabilities. Materials and methods: Using a qualitative approach to explore individuals' subjective perspectives in depth, five community-dwelling adults (age 52-72, 2 female, 3 male) living with chronic mobility impairments after stroke that restrict independent PA were interviewed. A semi structured topic guide based on the theoretical domains framework was utilized. The interview data was analyzed thematically, and the theoretical domains framework constructs were mapped onto the main and sub-categories. Results: The six main categories of facilitators and barriers along the capability, opportunity, motivation-behavior (COM-B) framework were: (1) physical capabilities, (2) psychological capabilities, (3) motivation reflective, (4) motivation automatic, (5) opportunity physical, and (6) opportunity social. The physical capabilities to independently perform PA were variable between participants but were not necessarily perceived as a barrier. Participants were highly motivated to maintain and/or increase their abilities to master their everyday lives as independently as possible. It became clear that a lack of physical opportunities, such as having access to adequate training facilities can present a barrier. Social opportunities in the form of social support, social norms, or comparisons with others can act as both facilitators and barriers. Conclusion: While confirming known barriers and facilitators that impact the ability of individuals with functional limitations to be active, the findings highlight the need and opportunities for comprehensive service models based on interdisciplinary collaborations.

Stability boots for the treatment of Achilles tendon injuries: Gait analysis of healthy participants.

BACKGROUND: Achilles tendon injuries are commonly treated with stability boots that secure the ankle at a specific position and aim to reduce loading of the tendon. These boots allow full weight bearing by limiting the range of movement. It is, however, unknown, to what extent these boots can reduce tendon loading and if the biomechanics are altered during walking. RESEARCH QUESTION: How do orthopedic boots influence lower extremity biomechanics during walking? METHODS: For this cross-sectional study, ten healthy participants walked with three orthopedic boots (Oped Vacoped, Kuenzli Ortho Rehab Absolut, Orthotech Variostabil) commonly used to treat Achilles tendon injuries. Kinematics and kinetics of the lower extremity of the booted leg and spatiotemporal parameters of both sides were collected using motion-capturing system and dynamometry. Each boot was tested in the maximally plantarflexed position. Group differences between boot conditions were analyzed by means of repeated-measures ANOVA and post-hoc paired t-test. RESULTS: The boot dorsiflexion range of motion differed significantly between boots with Vacoped (1.8° (0.3)) showing the smallest range, followed by Kuenzli (5.0° (1.3)) and Orthotech (7.9° (1.7)). Orthotech displayed a higher peak plantarflexion moment (1.36 Nm/kg (0.09)) than both Kuenzli (1.06 Nm/kg (0.12)) and Vacoped (1.04 Nm/kg (0.14)). Concerning loading over time, significant differences in the plantarflexion impulse were found, with the highest impulse in Vacoped (0.42 Nms/kg (0.06)), followed by Orthotech (0.29 Nms/kg (0.03)) and Kuenzli (0.25 Nms/kg (0.05)). In addition, asymmetries were seen in stance and step length for the booted and contralateral sides. SIGNIFICANCE: The lower extremity biomechanics were affected by the boots, with Kuenzli showing the lowest joint loading, Vacoped the smallest joint motion and Orthotech the most natural gait pattern. Future research is needed to determine the most relevant variable expressing the risk of re-rupture of the Achilles tendon in order to conclude which boot may be most favorable to use in clinical practice.

Human ankle joint movements during walking are probably not determined by talar morphology.

Knowledge about the orientation of a representative ankle joint axis is limited to studies of tarsal morphology and of quasistatic movements. The aim of our study was therefore to determine the development of the axis orientation during walking. Intracortical bone pins were used to monitor the kinematics of the talus and tibia of five healthy volunteers. The finite helical axis was determined for moving windows of 10% stance phase and its orientation reported if the rotation about the axis was more than 2°. A representative axis for ankle dorsi- and plantarflexion was also estimated based on tarsal morphology. As reported by literature, the morphology-based axis was inclined more medially upwards for dorsiflexion than for plantarflexion. However, when a mean of the finite helical axis orientations was calculated for each walking trial for dorsiflexion (stance phase 15-25%) and for plantarflexion (stance phase 85-95%), the inclination was less medially upwards in dorsiflexion than in plantarflexion in four out of five participants. Thus, it appears that the inclination of a representative ankle joint axis for dynamic loading situations cannot be estimated from either morphology or quasi-static experiments. Future studies assessing muscle activity, ligament behaviour and articulating surfaces may help to identify the determining factors for the orientation of a representative ankle joint axis.

Surface electromyographic activity of trunk muscles during trunk control exercises for people after stroke; effect of a mobile and stable seat for rehabilitation.

The aim of this study was to explore differences in trunk muscle activity on a stable and mobile seat for people after stroke and healthy participants. Trunk control exercises are known to have a beneficial effect on trunk control, balance, and mobility after stroke. The effect of such exercises could be enhanced by the use of a mobile seat to provide further training stimuli. However, little research on the musculoskeletal effects of trunk training on mobile seats has been carried out. On a stable and a mobile seat, thirteen people after stroke and fifteen healthy participants performed two selective trunk control exercises, which were lateral flexion initiated by the pelvis and the thorax. The maximal surface electromyography relative to static sitting of the muscles multifidus, erector spinae, and obliquus externus was recorded bilaterally. The effects of group, seat condition, trunk control exercise, and muscle side were investigated employing within-subject linear-mixed-models. Compared to the stable seat, the maximal muscle activity of people after stroke on the mobile seat was higher during the thorax-initiated exercise and lower during the pelvis-initiated exercise. Healthy participants showed opposite results with higher muscle activity on the mobile seat during the pelvis-initiated exercise. For trunk control training on a mobile seat with high muscle activation people after stroke should perform trunk control exercises initiated by the thorax, for training with lower muscle activity people after stroke should initiate selective trunk movements by the pelvis. The results can support the planning of progressive trunk control rehabilitation programs.

Evaluation of a passive exoskeleton for static upper limb activities.

The aim of this study was to evaluate the effect of a passive upper body exoskeleton on muscle activity, perceived musculoskeletal effort, local perceived pressure and subjective usability for a static overhead task. Eight participants (4 male, 4 female) held a load (0 kg and 2 kg) three times overhead for a duration of 30 s each, both with and without the exoskeleton. Muscle activity was significantly reduced for the Biceps Brachii (49%) and Medial Deltoid (62%) by the device for the 2 kg load. Perceived effort of the arms was significantly lower with the device for the 2 kg load (41%). The device did not have a significant effect on trunk or leg muscle activity (for the 2 kg load) or perceived effort. Local perceived pressure was rated below 2 (low pressure levels) for all contact areas assessed. Half of the participants rated the device usability as acceptable. The exoskeleton reduced muscle activity and perceived effort by the arms, and had no significant negative effect on the trunk and lower body with regards to muscle activity, perceived effort and localised discomfort.

Accuracy of KinectOne to quantify kinematics of the upper body.

Motion analysis systems deliver quantitative information, e.g. on the progress of rehabilitation programs aimed at improving range of motion. Markerless systems are of interest for clinical application because they are low-cost and easy to use. The first generation of the Kinect™ sensor showed promising results in validity assessment compared to an established marker-based system. However, no literature is available on the validity of the new 'Kinect™ for Xbox one' (KinectOne) in tracking upper body motion. Consequently, this study was conducted to analyze the accuracy and reliability of the KinectOne in tracking upper body motion. Twenty subjects performed shoulder abduction in frontal and scapula plane, flexion, external rotation and horizontal flexion in two conditions (sitting and standing). Arm and trunk motion were analyzed using the KinectOne and compared to a marker-based system. Comparisons were made using Bland Altman statistics and Coefficient of Multiple Correlation. On average, differences between systems of 3.9±4.0° and 0.1±3.8° were found for arm and trunk motion, respectively. Correlation was higher for the arm than for the trunk motion. Based on the observed bias, the accuracy of the KinectOne was found to be adequate to measure arm motion in a clinical setting. Although trunk motion showed a very low absolute bias between the two systems, the KinectOne was not able to track small changes over time. Before the KinectOne can find clinical application, further research is required analyzing whether validity can be improved using a customized tracking algorithm or other sensor placement, and to analyze test-retest reliability.

Between-day reliability of three-dimensional motion analysis of the trunk: A comparison of marker based protocols.

Motion capture of the trunk using three-dimensional optoelectronic systems and skin markers placed on anatomical landmarks is prone to error due to marker placement, thus decreasing between-day reliability. The influence of these errors on angular output might be reduced by using an overdetermined number of markers and optimization algorithms, or by defining the neutral position using a reference trial. The purpose of this study was to quantify and compare the between-day reliability of trunk kinematics, when using these methods. In each of two sessions, 20 subjects performed four movement tasks. Trunk kinematics were established through the plug-in-gait protocol, the point cloud optimization algorithm, and by defining upright standing as neutral position. Between-day reliability was analyzed using generalizability theory and quantified by indexes of dependability. Across all movement tasks, none of the methods was superior in terms of between-day reliability. The point cloud algorithm did not improve between-day reliability, but did result in 24.3% greater axial rotation angles. The definition of neutral position by means of a reference trial revealed 5.8% higher indexes of dependability for lateral bending and axial rotation angles, but 13.7% smaller indexes of dependability for flexion angles. Further, using a reference trial resulted in 8.3° greater trunk flexion angles. Therefore, the selection of appropriate marker placement and the corresponding calculation of angular output are dependent on the movement task and the underlying research question.

Measuring lumbar reposition accuracy in patients with unspecific low back pain: systematic review and meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To evaluate if patients with nonspecific chronic low back pain (NSCLBP) show a greater lumbar reposition error (RE) than healthy controls. SUMMARY OF BACKGROUND DATA: Studies on lumbar RE in patients with NSCLBP present conflicting results. METHODS: A systematic review and meta-analysis of the available literature were performed to evaluate differences in RE between patients with NSCLBP and healthy controls. Data on absolute error, constant error (CE), and variable error were extracted and effect sizes (ESs) were calculated. For the CE flexion pattern and active extension pattern, subgroups of patients with NSCLBP were analyzed. Results of homogeneous studies were pooled. Measurement protocols and study outcomes were compared. The quality of reporting and the authors' appraisal of risk of bias were investigated. RESULTS: The original search revealed 178 records of which 13 fulfilled the inclusion criteria. The majority of studies showed that patients with NSCLBP produced a significantly larger absolute error (ES, 0.81; 95% confidence interval [95% CI], 0.13-1.49) and variable error (ES, 0.57; 95% CI, 0.05-1.09) compared with controls. CE is direction specific in flexion and active extension pattern subgroups of patients with NSCLBP (ES, 0.39; 95% CI, -1.09 to 0.3) and ES, 0.18; 95% CI, -0.3 to 0.65, respectively). The quality of reporting and the authors' appraisal of risk of bias varied considerably. The applied test procedures and instrumentation varied between the studies, which hampered the comparability of studies. CONCLUSION: Although patients with NSCLBP seemed to produce a larger lumbar RE compared with healthy controls, study limitations render firm conclusions unsafe. Future studies should pay closer attention to power, precision, and reliability of the measurement approach, definition of outcome measures, and patient selection. We recommend a large, well-powered, prospective randomized control study that uses a standardized measurement approach and definitions for absolute error, CE, and variable error to address the hypothesis that proprioception may be impaired with CLBP.

The effect of lateral banking on the kinematics and kinetics of the lower extremity during lateral cutting movements.

There are many aspects of cutting movements that can limit performance, however, the implementation of lateral banking may reduce some of these limitations. Banking could provide a protective mechanism, placing the foot and ankle in orientations that keep them out of dangerous positions. This study sought to determine the effect of two banking angles on the kinematics and kinetics of the lower extremity during two athletic maneuvers. Kinematic and kinetic data were collected on 10 recreational athletes performing v-cuts and side shuffle movements on different banked surfaces (0°, 10°, 20°). Each sample surface was rigidly attached to the force platform. Joint moments were calculated and compared between conditions using a repeated measures ANOVA. Banking had a pronounced effect on the ankle joint. As banking increased, the amount of joint loading in the transverse and frontal planes decreased likely leading to a reduction in injury risk. Also an increase in knee joint loading in the frontal plane was seen during the 20° bank during the v-cut. Conversely loading in the sagittal plane at the ankle joint increased with banking and coupled with a reorientation of the ground reaction vector may facilitate a performance increase. The current study indicates that the 10° bank may be the optimal bank, in that it decreases ankle joint loading, as well as increases specific performance variables while not increasing frontal plane knee joint loading. If banking could be incorporated in footwear it may be able to provide a protective mechanism for athletes.

The shifting of the torsion axis of the foot during the stance phase of lateral cutting movements.

Previously, foot torsion has been studied with respect to peak angles during athletic movements. Athletic footwear often contains a torsion element that dictates a torsion axis of the shoe. The location of the axis of rotation of the foot is, however, unknown. Therefore, the purpose of this study was to describe the torsion axis location during the stance phase of lateral cutting movements. Thirty-nine subjects performed a barefoot lateral jab and 19 subjects performed a barefoot shuffle cut. Markers were placed on the fore- and rearfoot and their movement was quantified using a 3-D video system. The torsion axis location was determined using a modified finite helical axis approach during the stance phase while the torsion angle was calculated as the amount of rotation around the torsion axis. At the beginning of the stance phase, the axis was located on the medial aspect of the foot. During the stance phase, the axis shifted towards the lateral side of the foot before the axis moved back to the medial aspect of the foot at the end of stance. For both movements significant correlations between the axis location in the vertical and medio-lateral directions and the torsion angle were found. With larger torsion (forefoot inversion) angles the axis was in a more lateral and plantar location within the foot. With this knowledge, a shoe torsion system where the shoe torsion axis location is in agreement with the foot axis location could be developed.

Effect of relative marker movement on the calculation of the foot torsion axis using a combined Cardan angle and helical axis approach.

The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location.