Showing papers on "Stair climbing published in 2021"

Functional design of a hybrid leg-wheel-track ground mobile robot

Abstract: This paper presents the conceptual and functional design of a novel hybrid leg-wheel-track ground mobile robot for surveillance and inspection, named WheTLHLoc (Wheel-Track-Leg Hybrid Locomotion). The aim of the work is the development of a general-purpose platform capable of combining tracked locomotion on irregular and yielding terrains, wheeled locomotion with high energy efficiency on flat and compact grounds, and stair climbing/descent ability. The architecture of the hybrid locomotion system is firstly outlined, then the validation of its stair climbing maneuver capabilities by means of multibody simulation is presented. The embodiment design and the internal mechanical layout are then discussed.

Lower-limb kinematics and kinetics during continuously varying human locomotion.

Abstract: Human locomotion involves continuously variable activities including walking, running, and stair climbing over a range of speeds and inclinations as well as sit-stand, walk-run, and walk-stairs transitions. Understanding the kinematics and kinetics of the lower limbs during continuously varying locomotion is fundamental to developing robotic prostheses and exoskeletons that assist in community ambulation. However, available datasets on human locomotion neglect transitions between activities and/or continuous variations in speed and inclination during these activities. This data paper reports a new dataset that includes the lower-limb kinematics and kinetics of ten able-bodied participants walking at multiple inclines (±0°; 5° and 10°) and speeds (0.8 m/s; 1 m/s; 1.2 m/s), running at multiple speeds (1.8 m/s; 2 m/s; 2.2 m/s and 2.4 m/s), walking and running with constant acceleration (±0.2; 0.5), and stair ascent/descent with multiple stair inclines (20°; 25°; 30° and 35°). This dataset also includes sit-stand transitions, walk-run transitions, and walk-stairs transitions. Data were recorded by a Vicon motion capture system and, for applicable tasks, a Bertec instrumented treadmill. Machine-accessible metadata file describing the reported data: https://doi.org/10.6084/m9.figshare.16611523

Active knee joint exoskeleton for stair ascent augmentation

Abstract: Stair climbing is a strenuous daily movement that is challenging for older adults and those with lower limb weakness. In this study, we describe a novel stairclimbing exoskeleton that was designed to help weak-kneed people to climb stairs and help workers to carry heavy loads up stairs (Figure 1(a)). The exoskeleton has a hybrid control method that enables different performances in the stance phase and the swing phase. A switching controller guarantees the stability of the transition. Evaluations have showed that the exoskeleton can produce the torque required for stairclimbing. Level ground walking and stairclimbing need different driving powers and joint motion ranges in both the sagittal and frontal planes [1]. During level ground walking, the knee joint acts as a passive joint, while the hip and ankle joints provide the driving forces [2]. In contrast, the motions during stairclimbing are mainly driven by the hip and knee joints in the frontal and sagittal planes, respectively [3]. Research on kinetics shows that stairclimbing requires more torque in the knee joint than that required during level ground walking, and that the torque of the knee joint is much larger than that of the other joints [4]. During stairclimbing, the knee joint provides more power and assistance than the hip joint. Thus, we considered that a powered knee joint exoskeleton would aid in stairclimbing. Mechanical design. The robotic knee was designed as an active joint that helps the exoskeleton robot lift and support the human body in the stair ascent process. The knee joint reportedly requires a large amount of driving torque [3, 5]. Thus, if a motor and speed reducer system had been adopted directly, the mass and size of the driving system would have been unacceptably large, and so a new approach was needed to achieve this driving torque. We developed a linkage topology mechanism to overcome the contradiction between mass and driving torque [6]. The mechanical structure is illustrated in Figure 1(b). The rotational motion of the motor can be converted to the linear motion of the nut-slider through the ball screw, and the rotational movement of the shank can be transferred from the crank mechanism. A shell (30 mm thick and 60 mm wide) has been created to contain the motor, crank mechanism, and other auxiliary devices. The leg, including the knee joint and the thigh, had a total weight of 2.9 kg, and the driving torque could be as large as 180 Nm. The knee joint needs distinct angular displacements and torque in the stair ascent process compared with level ground walking [1, 3]. After the foot strikes the stairs, the joint moment increases considerably to support the body, while the joint displacement decreases to unbend the standing leg [4]. The simulation results of the torque and angular displacement of the joint showed that the proposed linkage knee joint supplied its largest moment at about 95 (Figure 1(c)), and thus met the requirements of stairclimbing [3]. Hybrid control of the robot. The exoskeleton robot applied a hybrid controller to fulfill the varying demands in different walking states. Different control strategies were used in the two phases (stance and swinging) and during transition between phases. The walking phase was identified by embedded contact sensors installed in the shoes. Each leg of the exoskeleton was treated as a serial robot. The kinetic equation of the leg was

Brief Vigorous Stair Climbing Effectively Improves Cardiorespiratory Fitness in Patients With Coronary Artery Disease: A Randomized Trial

Abstract: Background: Cardiac rehabilitation exercise reduces the risk of secondary cardiovascular disease. Interval training is a time-efficient alternative to traditional cardiac rehabilitation exercise and stair climbing is an accessible means. We aimed to assess the effectiveness of a high-intensity interval stair climbing intervention on improving cardiorespiratory fitness ( V ˙ O 2 peak ) compared to standard cardiac rehabilitation care. Methods: Twenty participants with coronary artery disease (61 ± 7 years, 18 males, two females) were randomly assigned to either traditional moderate-intensity exercise (TRAD) or high-intensity interval stair climbing (STAIR). V ˙ O 2 peak was assessed at baseline, following 4 weeks of six supervised exercise sessions and after 8 weeks of ~24 unsupervised exercise sessions. TRAD involved a minimum of 30 min at 60-80%HRpeak, and STAIR consisted of three bouts of six flights of 12 stairs at a self-selected vigorous intensity (~90 s/bout) separated by recovery periods of walking (~90 s). This study was registered as a clinical trial at clinicaltrials.gov (NCT03235674). Results: Two participants could not complete the trial due to the time commitment of the testing visits, leaving n = 9 in each group who completed the interventions without any adverse events. V ˙ O 2 peak increased after supervised and unsupervised training in comparison to baseline for both TRAD [baseline: 22.9 ± 2.5, 4 weeks (supervised): 25.3 ± 4.4, and 12 weeks (unsupervised): 26.5 ± 4.8 mL/kg/min] and STAIR [baseline: 21.4 ± 4.5, 4 weeks (supervised): 23.4 ± 5.6, and 12 weeks (unsupervised): 25 ± 6.2 mL/kg/min; p (time) = 0.03]. During the first 4 weeks of training (supervised) the STAIR vs. TRAD group had a higher %HRpeak (101 ± 1 vs. 89 ± 1%; p ≤ 0.001), across a shorter total exercise time (7.1 ± 0.1 vs. 36.7 ± 1.1 min; p = 0.009). During the subsequent 8 weeks of unsupervised training, %HRpeak was not different (87 ± 8 vs. 96 ± 8%; p = 0.055, mean ± SD) between groups, however, the STAIR group continued to exercise for less time per session (10.0 ± 3.2 vs. 24.2 ± 17.0 min; p = 0.036). Conclusions: Both brief, vigorous stair climbing, and traditional moderate-intensity exercise are effective in increasing V ˙ O 2 peak , in cardiac rehabilitation exercise programmes.

Lower-Limb-Assisting Robotic Exoskeleton Reduces Energy Consumption in Healthy Young Persons during Stair Climbing.

Abstract: Many robotic exoskeletons for lower limb assistance aid walking by reducing energy costs. However, investigations examining stair-climbing assistance have remained limited, generally evaluating reduced activation of related muscles. This study sought to investigate how climbing assistance by a robotic exoskeleton affects energy consumption. Ten healthy young participants wearing a robotic exoskeleton that assists flexion and extension of hip and knee joints walked up nine flights of stairs twice at a self-selected speed with and without stair-climbing assistance. Metabolic cost was assessed by measuring oxygen consumption, heart rate, and the time to climb each flight of stairs. Net oxygen cost (NOC) and total heart beats (THB) were used as measures of metabolic cost, accounting for different climbing speeds. Stair-climbing assistance reduced NOC and THB by 9.3% (P < 0.001) and 6.9% (P = 0.003), respectively, without affecting climbing speed. Despite lack of individual optimization, assistive joint torque applied to the hip and knee joints reduced metabolic cost and cardiovascular burden of stair climbing in healthy young males. These results may be used to improve methods for stair ascent assistance.

Home-Based Stair Climbing as an Intervention for Disease Risk in Adult Females; A Controlled Study.

Abstract: Cardiovascular disease and the metabolic syndrome are major contributors to health care expenditure. Increased physical activity reduces disease risk. The study compared effects of walking up and down stairs at home with continuous, gym-based stair climbing on the disease risk factors of aerobic fitness, serum lipids, body composition, fasting blood glucose, and resting cardiovascular variables. Sedentary women (31.7 ± 1.4 years) were randomly assigned to home-based (n = 26) or gym-based (n = 24) climbing for five days.week-1 over an eight-week period. Each ascent required a 32.8-m climb, with home-based climbing matching the vertical displacement in the gym. Participants progressed from two ascents.day-1 to five ascents.day-1 in weeks 7 and 8. Relative to controls, stair climbing improved aerobic fitness (V˙O2max +1.63 mL.min-1.kg-1, 95% CI = 1.21-2.05), body composition (weight -0.99 kg, 95% CI = 1.38-0.60), and serum lipids (LDL cholesterol -0.20 mmol.L-1, 95% CI = 0.09-0.31; triglycerides -0.21 mmol.L-1, 95% CI = 0.15-0.27), with similar risk reductions for home and gym-based groups. Only the home-based protocol reduced fasting blood glucose. Discussion focuses on stair climbing bouts as time-efficient exercise and the potential benefits of a home-based intervention. Stair use at home offers a low-cost intervention for disease risk reduction to public health.

Prefrontal Cortex Involvement during Dual-Task Stair Climbing in Healthy Older Adults: An fNIRS Study

Abstract: Executive function and motor control deficits adversely affect gait performance with age, but the neural correlates underlying this interaction during stair climbing remains unclear. Twenty older adults (72.7 ± 6.9 years) completed single tasks: standing and responding to a response time task (SC), ascending or descending stairs (SMup, SMdown); and a dual-task: responding while ascending or descending stairs (DTup, DTdown). Prefrontal hemodynamic response changes (∆HbO2, ∆HbR) were examined using functional near-infrared spectroscopy (fNIRS), gait speed was measured using in-shoe smart insoles, and vocal response time and accuracy were recorded. Findings revealed increased ∆HbO2 (p = 0.020) and slower response times (p < 0.001) during dual- versus single tasks. ∆HbR (p = 0.549), accuracy (p = 0.135) and gait speed (p = 0.475) were not significantly different between tasks or stair climbing conditions. ∆HbO2 and response time findings suggest that executive processes are less efficient during dual-tasks. These findings, in addition to gait speed and accuracy maintenance, may provide insights into the neural changes that precede performance declines. To capture the subtle differences between stair ascent and descent and extend our understanding of the neural correlates of stair climbing in older adults, future studies should examine more difficult cognitive tasks.

Stair climbing activity and vascular function in patients with hypertension.

Abstract: We evaluated the relationship between daily stair climbing activity and vascular function as assessed by flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation (NID). This study was a cross-sectional study. A total of 374 patients with hypertension were enrolled. The subjects were divided into three groups based on their daily stair climbing habit: no stairs group, climbing stairs to the 2nd-floor group, and climbing stairs to the ≥3rd-floor group. There was a significant difference in FMD between the ≥3rd-floor group and the other two groups (3.3 ± 2.5% vs. 2.3 ± 2.7% and 2.4 ± 2.7%, p = 0.02, respectively). FMD values were similar in the no stairs group and the 2nd-floor group (p = 0.96). There was a significant difference in NID between the no stairs group and the other two groups (7.4 ± 4.2% vs. 10.9 ± 5.3% and 11.3 ± 5.1%, p < 0.001, respectively). NID values were similar in the second-floor group and the ≥3rd-floor group (p = 0.86). These findings suggest that both endothelial function and vascular smooth muscle function are impaired in individuals who do not climb stairs and that endothelial function but not vascular smooth muscle function is impaired in individuals who climb stairs to the second floor compared with individuals who climb stairs to the ≥3rd floor. Stair climbing activity, a simple method for assessing daily physical activity, may reflect vascular function in patients with hypertension.

Daily stair climbing is associated with decreased risk for the metabolic syndrome.

Abstract: Background Stair climbing can be a vigorous lifestyle physical activity, and is associated with healthier lipoprotein profiles, lower body weight and blood pressure, as well as higher aerobic fitness. The present analysis of data from a cohort of late middle-aged men and women examined the association between daily stair climbing and the metabolic syndrome. Methods Data from 782 (423 women) participants (mean (SD) age 58.3 (0.95) years in the Dutch Famine Birth Cohort Study (2002-2004) were used to examine the cross-sectional association between self-reported daily stair climbing and the metabolic syndrome. Stair climbing was assessed by the question 'Do you climb stairs daily?' and the metabolic syndrome was defined using the established five components relating to lipid fractions, blood glucose levels, blood pressure and abdominal obesity. Results Not climbing stairs daily was associated with an increased incidence of the metabolic syndrome (OR = 1.90, 95% CI = 1.23, 2.92, p = 0.004) and a greater number of its components (F1,780 = 8.48, p = 0.004): these associations were still evident after adjusting for a variety of potential confounders. Conclusions The most likely explanation for the current findings is that daily stair climbing may be protective against the metabolic syndrome. This result reinforces public health recommendations for increased stair climbing with evidence from physiological outcomes.

Staircase design for health monitoring in elderly people

Abstract: The need for early detection and intervention for age-related health deterioration via home-based health monitoring systems is growing with global population aging. Health deterioration is typically evaluated using questionnaires, but obtaining frequent responses is difficult. Although stair walking involving a high physical load is suitable for assessing health deterioration, uniform assessment using home-based systems is difficult because different stair designs result in different movements. There is currently insufficient research on differences in evaluation performance between different stair designs. The current study aimed to develop an objective index to assess difficulties in activities of daily living (ADLs) as an indicator of health deterioration by observing stair walking, and to investigate the effects of stair dimensions on the relationship between the index and health deterioration. We hypothesized that knee joint positions during stair ascent would be associated with health deterioration, and developed the “Stepping in Level” index, reflecting the knee joint position when stepping in, obtained using a markerless depth information-based system. Seventy elderly people ascended two types of stairs (steep: 33.7°; shallow: 28.2°) and completed a questionnaire regarding ADL difficulty. We used a generalized linear mixed model to investigate the ability of “Stepping in Level” to explain ADL difficulty. The results revealed that “Stepping in Level” was able to explain ADL difficulty, and steep stairs were more suitable than shallow stairs for assessment. Our system enables daily assessment of difficulty in ADLs and detection of subtle changes in daily life. The current findings could inform design guidelines for health monitoring.

Dynamic Assessment of Femoroacetabular Impingement Syndrome Hips.

Abstract: Purpose The purpose of our study was to compare lower extremity rotational kinematics and kinetics (angles, torques, and powers) and hip muscle electromyography (EMG) activity between cam-type femoroacetabular impingement syndrome (FAIS) and age- and sex-matched controls during walking, fast walking, stair ascent, stair descent, and sit-to-stand. Methods This study included 10 males with unilateral FAIS and 10 control males with no FAIS. We measured kinematics, kinetics, and electromyographic signals during stair ascent/descent, sit-to-stand, self-selected walk, and fast walk. Peak signal differences between groups were compared with independent t-tests with statistical significance when P Results FAIS hips showed significant differences compared to controls, including increased hip flexion during walking (+4.9°, P = .048) and stair ascent (+7.8°, P =.003); diminished trunk rotation during stair ascent (−3.4°; P = .015), increased knee flexion during self-selected walking (+5.1°, P = .009), stair ascent (+7.4°, P = .001), and descent (+5.3°, P = .038); and increased knee valgus during fast walking (+4.7°, P = .038). gMed and MedHam showed significantly decreased activation in FAIS during walking (gMed: −12.9%, P = .002; MedHam: −7.4%, P = .028) and stair ascent (gMed: −16.7%, P = .036; MedHam: −13.0%, P = .041); decreased gMed activation during sit-to-stand (−8.8%, P = .004) and decreased MedHam activation during stair descent (−8.0%, P = .039). Conclusions Three-dimensional motion analysis and EMG evaluation of functional kinematics and kinetics in subjects with symptomatic unilateral cam-type FAIS across a spectrum of provocative tasks demonstrated significant differences compared to controls in hip flexion, trunk rotation, knee flexion, and valgus. FAIS hips had significantly decreased gMed and MedHam activity. These findings may explain altered torso-pelvic, hip, and knee mechanics in FAIS patients and suggest that evaluation of FAIS should include the patient’s hip, knee, and torso-pelvic relationships and muscle function. Clinical Relevance The clinical and functional manifestation of FAIS hip pathomechanics is not entirely understood, and previous literature to date has not clearly described the alterations in gait and functional movements seen in patients with cam-type FAIS. The current study used 3D motion analysis and EMG evaluation of functional kinematics and kinetics to identify a number of differences between FAIS and control hips, which help us better understand the lower extremity kinematics and kinetics and muscle activation in FAIS.

Design of A Wheel-Legged Stair Climbing Robot

Abstract: This paper presents a wheel-legged robot capable of overcoming steps and climbing stairs with six linear actuators as legs. With its control algorithm, this design can conquer irregular stairs with high operation stability. We built our physical prototype and developed the climbing procedures for a single stair and multiple stairs. Experiment results showed the feasibility of our mechanical design and the effectiveness of its climbing algorithms. The leg-wheel platform design and climbing algorithms show the potential application in various areas include service robots, goods transportation, and wheelchairs.

Knee Extensor Muscle Strength Is More Important Than Postural Balance for Stair-Climbing Ability in Elderly Patients with Severe Knee Osteoarthritis.

Abstract: Knee osteoarthritis is a chronic joint disease which damages articular cartilage In its severe stages, it results in impairments in balance and muscle strength loss, which affect daily life activities such as walking or climbing stairs This study sought to investigate associated factors with stair-climbing ability in this population, with special interest in measuring the relevance of postural balance for this task Forty-four patients scheduled to undergo unilateral total knee arthroplasty were assessed Timed up and go test, stair ascent-descent test, three different isometric strength tests (knee flexion, knee extension and hip abduction), active knee extension and flexion range of movement and static postural balance assessment were evaluated Spearman's correlation coefficients and multiple linear regression analysis determined the strength of association between the different variables and stair-climbing time No significant association between the stair-climbing time and static balance was found Significant associations were found between stair-climbing time and timed up and go (r = 071; p < 00001) and maximal knee extensor strength (r = -052; p = 00003) One-year increase in age was associated with 015 s (95% CI 000 to 030) slower stair-climbing time In conclusion, muscle strength is more important than postural balance for stair-climbing ability in this population

Stair Climbing Capability-Based Dimensional Synthesis for the Multi-legged Robot

Abstract: Staircase is a typical obstacle for the legged robot to overcome in buildings. This paper studies the stair climbing capability-based dimensional synthesis for a hexapod legged robot, i.e., exploring how to determine the leg length and the longitudinal body length concerning the target staircase in the mechanical design stage. In climbing a staircase, leg-staircase interference is one of the predominant issues. The three possible interference cases are illustrated in detail with a 2-DOF (degree of freedom) leg mechanism and the staircase size, based on the predefined tripod gait sequence. The mathematical relationships between the leg length, longitudinal body length, and the target staircase size are derived. The leg length and the body length are finally determined with the target staircase size. The virtual simulations and prototype experiments verify the effectiveness of the dimensional synthesis for the hexapod robot.

A Ground-Stair Walking Strategy of the Assistive Device Based on the RGB-D Camera

Abstract: To ensure the safety of elderly people with a walking assistive device during the ground-stair transition, a system which could automatically transfer the walking mode between level walking and stair climbing was proposed A road condition detection system with a RGB-D Camera and ultrasonic sensors was utilized in this system The walking mode transformation is triggered by the detection of environment change When far approach the stairs, the RGB-D Camera is responsible for the stair detection The ultrasonic sensors are used in the near-approach of stairs and stair traversal The ultrasonic sensors were mounted on the toe and heel to find the upwards and downwards stairs respectively During stair traversal, if the ultrasonic sensors find the foot of the device is too closed to the edge of stairs, the target trajectory will be higher and the stride will be adjusted to prevent collisions The Impedance control was introduced to let the device trace the predefined walking trajectories In experiments, the device changed walking modes successfully when getting close the stairs The results engaged in three subjects showed that the foot height was increased compared without assistance Thus a huge potential can be expected that this system can solve the adaptability of walking assistive devices to different surroundings

Stair climbing and mortality: a prospective cohort study from the UK Biobank.

Abstract: Background Regular stair climbing has the potential to lower the risk of premature death, but current evidence is scarce. We aimed to examine whether daily stair climbing is associated with lower risk of all-cause, cancer, and cardiovascular disease (CVD) mortality. Methods Using the UK Biobank cohort, we extracted information of self-reported daily flights of stairs climbed at home, categorized as none, 1 to 5, 6 to 10, 11 to 15, and ≥16 flights per day. Associations between flights of stair climbed per day and mortality were examined as hazard ratios (HRs) from Cox proportional hazards models adjusted for demographic, clinical, and behavioural covariates including time spent in other physical activities. We calculated the restricted mean survival time as an absolute measure of association. The risk of residual confounding was examined using propensity score matching and by using lung cancer as negative control outcome. Participants were followed from baseline (2006–2010) through 31 March 2020. Results A total of 280 423 participants (median follow-up 11.1 years, during which 9445 deaths occurred) were included. Compared with not climbing any stairs, climbing more than five flights of stairs at home per day was associated with lower risk of premature mortality. The lowest risk was found for those climbing 6–10 flights per day: 0.91; 95% confidence interval (CI): 0.85, 0.98, translated to approximately 44 to 55 days of additional survival. A similar pattern was found after applying propensity score matching and for cancer mortality (6–10 flights per day HR: 0.88; 95% CI: 0.80, 0.97), but not for CVD mortality (6–10 flights per day HR: 1.08; 95% CI: 0.91, 1.29). The association between stair climbing and lung cancer was similar to that of all-cause mortality. Conclusions Climbing more than five flights of stairs at home per day was associated with a lower risk of all-cause and cancer mortality, but not CVD mortality, compared with those who did not take the stairs. The magnitude of the association was small and appeared susceptible to residual confounding. It is unlikely that at-home stair climbing is sufficient physical activity stimuli to lower the risk of premature mortality.

Toward Generalization of Bipedal Gait Cycle During Stair Climbing Using Learning From Demonstration

Abstract: Lower limb assistive exoskeletons for rehabilitation is a growing field of study. They allow people with spinal cord injuries and strokes to stand upright and walk. Exoskeleton controls research typically focuses on trajectory generation, motion control over the trajectories, and balance and stability. This work focuses on the generalization of people’s joint trajectories climbing a single stair, for an exoskeleton to be developed for people of all leg lengths and be used on variable stair heights. The motion of subjects of different heights, ages, and genders climbing a single stair was collected using motion capture. By using Gaussian mixed regression and Gaussian mixed models, these trajectories were combined to build a model that generalizes individuals with different leg lengths, genders, ages and stair heights. The variability of the subject’s leg length is accounted for by tracking a marker on the toe of the subject and using inverse kinematics to calculate the joint angles. The analysis in this paper shows that joint angles can be generalized to climb various stair heights. In addition, an open-source database of motion capture climbing data and an open-source framework for generating joint trajectories has been made available for public use.

Design and Implementation of Involute-Curve-Shaped-Mechanism for Stair Climbing

Abstract: For stair climbing by a mobile robot, we discussed a 1-DOF mechanism that allows a rotating axis to be lifted with less torque. A prototype robot equipped involute-curve-shaped mechanism which is obtained from that discussion was developed and a control method for stair climbing was proposed. Furthermore, it was confirmed by experiments that the robot autonomously climbs stairs.

Fabrication of Stair Climbing Trolley

Abstract: The stair climbing trolley is developing easy mechanism for transportation of heavy loads in over stairs. The transfer of heavy load from bottom floor to top floor is very difficult by using single wheel. In production or manufacturing factory transfer by means of crane or lifting machines. The hand trolleys are used to relief the stress of lifting while on flat ground. This paper describes the research of stair climbing trolley. In civil construction sites or also in home such kinds of instrument are not in used so the transfer load on top floor is difficult. The stair climbing trolley is hand trolley to carry heavy load up the stair with less effort and with manually. In stair climbing trolley tri-star wheel is used to carry load on top floor and down the floor stairs. Also it is very low maintenance.

Evaluation of a novel stair-climbing transportation aid for emergency medical services.

Abstract: Acute and planned transportations of patients are major tasks for emergency medical services (EMS) and often result in substantial physical strains with a major impact on the workers' health, because current transportation aids cannot provide sufficient support, especially on stairs. A new stair-climbing and self-balancing approach (SEBARES) has been developed and its usability is evaluated in the context of this paper. Twelve participants operated a prototype in a transportation scenario and user forces, user joint angles and the perceived usability were evaluated. Results show that user forces were within long-term acceptable ergonomic limits for over 90% of the transportation time and a mainly healthy upright posture of the back could be maintained. This resulted in a healthy working posture for 85% of the time, according to the OWAS method, and a good perceived usability. A comparison to the most ergonomic aid according to literature, a caterpillar stair chair, reveals that similar upright postures are assumed, while the operation of SEBARES required only 47% of the forces to operate the caterpillar stair chair. A comparison to a previous field study indicates a reduction of strenuous working postures by a factor of three, which further confirms the ergonomic advantages of this concept.

Early biomechanical outcome in patients with acetabular fractures treated using the pararectus approach: a gait and stair climb analysis study

Abstract: Patients with surgically treated acetabular fractures using extensive dissection of hip muscles demonstrate an incomplete biomechanical recovery and limited joint mobility during movement. The purpose of this study was to evaluate the early biomechanical outcome in a series of patients with acetabular fractures treated using the less invasive anatomical pararectus approach. Eight patients (48 ± 14 years, BMI 25.8 ± 3 kg/m2) were investigated 3.8 ± 1.3 months after surgery and compared to matched controls (49 ± 13 years, BMI 26 ± 2.8 kg/m2). Trunk and lower extremity kinematics and kinetics during gait and stair climb were calculated. SF-12 and the Merle d’Aubigne score were used for functional evaluation. Statistical analysis was conducted using Mann–Whitney test and Student’s t test. Effect sizes were calculated using Cohen’s d. No group differences for lower extremity kinematics during walking and stair climbing were found. During walking, patients showed significant reductions (p < 0.05) of the vertical ground reaction force (8%) and knee and hip extension moments (29 and 27%). Ipsilateral trunk lean was significantly increased by 3.1° during stair descend while reductions of vertical ground reaction force were found for stair ascend (7%) and descend (20%). Hip extension moment was significantly reduced during stair descend by 37%. Patients revealed acceptable SF-12 physical and mental component outcomes and a good rating for the Merle d’Aubigne score (15.9 ± 1.7). Patients showed some biomechanical restrictions that can be related to residual deficits in weight bearing capacity and strength of the hip muscles. In contrast, an immediate recovery of mobility was achieved by preserving lower extremity and pelvic movement. Therefore, the pararectus approach can serve as a viable strategy in the surgical treatment of acetabular fractures. Trial registration number DRKS00011308, 11/14/2016, prospectively registered.

Comparison of different symmetry indices for the quantification of dynamic joint angles.

Abstract: Symmetry is a sign of physiological and healthy movements, as pathologies are often described by increased asymmetries. Nevertheless, based on precisely measured data, even healthy individuals will show small asymmetries in their movements. However, so far there do not exist commonly accepted methods and reference values for gait symmetry in a healthy collective. Therefore, a comparison and presentation of reference values calculated by 3 different methods of symmetry indices for lower limb joint angles during walking, ascending, and descending stairs were shown. Thirty-five healthy participants were analyzed during walking, ascending, and descending stairs with the help of the inertial measurement system MyoMotion. Using the normalized symmetry index (SInorm), the symmetry index (SI) as the integral of the symmetry function, and another normalized symmetry index (NSI), the symmetry of joint angles was evaluated. For statistical evaluation of differences, repeated measurement models and Bland–Altman-Plots were used. Apart from a bias between the symmetry indices, they were comparable in the predefined limits of 5%. For all parameters, significantly higher asymmetry was found for ankle dorsi/-plantarflexion, compared with the hip and knee flexion. Moreover, the interaction effect of the joint and movement factors was significant, with an increased asymmetry of the hip and knee during descending stairs greater than while ascending stairs or walking, but a reduced symmetry of the ankle during walking when compared to descending. The movement only showed significant effects when analyzing the SInorm. Even for healthy individuals, small asymmetries of movements were found and presented as reference values using 3 different symmetry indices for dynamic lower limb joint angles during 3 different movements. For the quantification of symmetrical movements differences between the joints, movements, and especially their interaction, are necessary to be taken into account. Moreover, a bias between the methods should be noted. The potential for each presented symmetry index to identify pathological movements or track a rehabilitation process was shown but has to be proven in further research. Trial registration: DRKS00025878.

Template-Based Recognition of Human Locomotion in IMU Sensor Data Using Dynamic Time Warping.

Abstract: Increased levels of light, moderate and vigorous physical activity (PA) are positively associated with health benefits. Therefore, sensor-based human activity recognition can identify different types and levels of PA. In this paper, we propose a two-layer locomotion recognition method using dynamic time warping applied to inertial sensor data. Based on a video-validated dataset (ADAPT), which included inertial sensor data recorded at the lower back (L5 position) during an unsupervised task-based free-living protocol, the recognition algorithm was developed, validated and tested. As a first step, we focused on the identification of locomotion activities walking, ascending and descending stairs. These activities are difficult to differentiate due to a high similarity. The results showed that walking could be recognized with a sensitivity of 88% and a specificity of 89%. Specificity for stair climbing was higher compared to walking, but sensitivity was noticeably decreased. In most cases of misclassification, stair climbing was falsely detected as walking, with only 0.2–5% not assigned to any of the chosen types of locomotion. Our results demonstrate a promising approach to recognize and differentiate human locomotion within a variety of daily activities.