Revision of hip flexor anatomy and function in modern humans, and implications for the evolution of hominin bipedalism.

Hip flexor musculature was instrumental in the evolution of hominin bipedal gait and in endurance running for hunting in the genus Homo. The iliacus and psoas major muscles were historically considered to have separate tendons with different insertions on the lesser trochanter. However, in the early 20th century, it became "common knowledge" that the two muscles insert together on the lesser trochanter as the "iliopsoas" tendon. We revisited the findings of early anatomists and tested the more recent paradigm of a common "iliopsoas" tendon based on dissections of hips and their associated musculature (n = 17). We rediscovered that the tendon of the psoas muscle inserts only into a crest running from the superior to anterior aspect of the lesser trochanter, separate from the iliacus. The iliacus inserts fleshly into the anterior portion of the lesser trochanter and into an inferior crest extending from it. We developed 3D multibody dynamics biomechanical models for: (a) the conjoint "iliopsoas" tendon hypothesis and (b) the separate insertion hypothesis. We show that the conjoint model underestimates the iliacus' capacity to generate hip flexion relative to the separate insertion model. Further work reevaluating the primate lower limb (including human) through dissection, needs to be performed to develop those datasets for reconstructing anatomy in fossil hominins using the extant phylogenetic bracket approach, which is frequently used for tetrapods clades outside of paleoanthropology.

Walking for hypertension.

BACKGROUND: Increased physical activity has been recommended as an important lifestyle modification for the prevention and control of hypertension. Walking is a low-cost form of physical activity and one which most people can do. Studies testing the effect of walking on blood pressure have revealed inconsistent findings. OBJECTIVES: To determine the effect of walking as a physical activity intervention on blood pressure and heart rate. SEARCH METHODS: We searched the following databases up to March 2020: the Cochrane Hypertension Specialised Register, CENTRAL (2020, Issue 2), Ovid MEDLINE, Ovid Embase, CINAHL, PsycINFO, SPORTDiscus, PEDro, the WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov. We also searched the following Chinese databases up to May 2020: Index to Taiwan Periodical Literature System; National Digital Library of Theses and Dissertation in Taiwan; China National Knowledge Infrastructure (CNKI) Journals, Theses & Dissertations; and Wanfang Medical Online. We contacted authors of relevant papers regarding further published and unpublished work. The searches had no language restrictions. SELECTION CRITERIA: Randomised controlled trials of participants, aged 16 years and over, which evaluated the effects of a walking intervention compared to non-intervention control on blood pressure and heart rate were included. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Where data were not available in the published reports, we contacted authors. Pooled results for blood pressure and heart rate were presented as mean differences (MDs) between groups with 95% confidence intervals (CIs). We undertook subgroup analyses for age and sex. We undertook sensitivity analyses to assess the effect of sample size on our findings. MAIN RESULTS: A total of 73 trials met our inclusion criteria. These 73 trials included 5763 participants and were undertaken in 22 countries. Participants were aged from 16 to 84 years and there were approximately 1.5 times as many females as males. The characteristics of walking interventions in the included studies were as follows: the majority of walking interventions was at home/community (n = 50) but supervised (n = 36 out of 47 reported the information of supervision); the average intervention length was 15 weeks, average walking time per week was 153 minutes and the majority of walking intensity was moderate. Many studies were at risk of selection bias and performance bias. Primary outcome We found moderate-certainty evidence suggesting that walking reduces systolic blood pressure (SBP) (MD -4.11 mmHg, 95% CI -5.22 to -3.01; 73 studies, n = 5060). We found moderate-certainty evidence suggesting that walking reduces SBP in participants aged 40 years and under (MD -4.41 mmHg, 95% CI -6.17 to -2.65; 14 studies, n = 491), and low-certainty evidence that walking reduces SBP in participants aged 41 to 60 years (MD -3.79 mmHg, 95% CI -5.64 to -1.94, P < 0.001; 35 studies, n = 1959), and those aged 60 years of over (MD -4.30 mmHg, 95% CI -6.17 to -2.44, 24 studies, n = 2610). We also found low certainty-evidence suggesting that walking reduces SBP in both females (MD -5.65 mmHg, 95% CI -7.89 to -3.41; 22 studies, n = 1149) and males (MD -4.64 mmHg, 95% CI -8.69 to -0.59; 6 studies, n = 203). Secondary outcomes We found low-certainty evidence suggesting that walking reduces diastolic blood pressure (DBP) (MD -1.79 mmHg, 95% CI -2.51 to -1.07; 69 studies, n = 4711) and heart rate (MD -2.76 beats per minute (bpm), 95% CI -4.57 to -0.95; 26 studies, n = 1747). We found moderate-certainty evidence suggesting that walking reduces DBP for participants aged 40 years and under (MD -3.01 mmHg, 95% CI -4.44 to -1.58; 14 studies, n = 491) and low-certainty evidence suggesting that walking reduces DBP for participants aged 41 to 60 years (MD -1.74 mmHg, 95% CI -2.95 to -0.52; 32 studies, n = 1730) and those aged 60 years and over (MD -1.33 mmHg, 95% CI -2.40 to -0.26; 23 studies, n = 2490). We found moderate-certainty evidence that suggests walking reduces DBP for males (MD -2.54 mmHg, 95% CI -4.84 to -0.24; 6 studies, n = 203) and low-certainty evidence that walking reduces DBP for females (MD -2.69 mmHg, 95% CI -4.16 to -1.23; 20 studies, n = 1000). Only 21 included studies reported adverse events. Of these 21 studies, 16 reported no adverse events, the remaining five studies reported eight adverse events, with knee injury being reported five times. AUTHORS' CONCLUSIONS: Moderate-certainty evidence suggests that walking probably reduces SBP. Moderate- or low-certainty evidence suggests that walking may reduce SBP for all ages and both sexes. Low-certainty evidence suggests that walking may reduce DBP and heart rate. Moderate- and low-certainty evidence suggests walking may reduce DBP and heart rate for all ages and both sexes.

[Evaluation of function and limiting factors of gait disorder treatment in cerebral palsy: development of the Walking Abilities Levels Classification System]. / Evaluación funcional y de factores limitantes del tratamiento de los trastornos de la marcha en la parálisis cerebral infantil: desarrollo del sistema de clasificación de niveles de deambulación funcional.

INTRODUCTION: The Gross Motor Function Classification System has allowed us to stratificate cerebral palsy patients, according to their walking abilities. The lack of sensitivity about detecting changes and the absence of a global patient evaluation, justify the search of new pre-operative evaluation tools. AIMS: To present the Walking Abilities Levels Classification System (WALCS) and to show the first inter-observer agreement study that has been carried out. This system uses first a different pattern for ordering gait functional skills, and after that, evaluates the reversibility of the contextual factors that may limit the result of a gait disorder treatment. SUBJECTS AND METHODS: A new evaluation frame was built by an interdisciplinary team with an average professional experience of more than 15 years, initially focused as part of the pre-surgical patient evaluation. An inter-observer agreement study was held to gain the first insight of it. 14 participants studied the medical reports and gait lab video images of 10 cases. RESULTS: The kappa index was 0.76 for the walking ability level, 0.79 for the biological type, 0.69 psychological type and 0.64 social type of limiting factors. CONCLUSIONS: The WALCS offers a new evaluation frame gathering patient walking skills and limiting factors treatment. The initial inter-observer agreement rate endorsed more intra- and inter-studies in order to achieve a more robust validation.

TITLE: Evaluación funcional y de factores limitantes del tratamiento de los trastornos de la marcha en la parálisis cerebral infantil: desarrollo del sistema de clasificación de niveles de deambulación funcional.Introducción. El Gross Motor Function Classification System ha permitido estratificar, según su habilidad para caminar, a los pacientes que padecen parálisis cerebral infantil. La falta de sensibilidad en la detección de cambios y la ausencia de una evaluación del paciente en el contexto en el que se encuentra justifican la búsqueda de alternativas de evaluación pretratamiento. Objetivos. Presentar y mostrar la concordancia interobservador inicial del sistema de clasificación de niveles de deambulación funcional. Con él se evalúa la destreza para caminar y la necesidad de asistencia para realizar transferencias desde la silla de ruedas, y, posteriormente se analiza el escenario que la salud y el entorno del paciente ofrecen como condicionantes en la corrección de la marcha o la bipedestación asistida. Sujetos y métodos. Se describe un nuevo marco de evaluación, elaborado por un grupo interdisciplinar con más de 15 años de experiencia media, enfocado inicialmente a la toma de decisiones antes de un tratamiento quirúrgico. Como control interno, 14 participantes evaluaron la historia clínica y los vídeos de marcha de 10 casos. Resultados. Se alcanzó un índice kappa de acuerdo de 0,76 en niveles funcionales y de 0,79 en el tipo de escenario biológico, de 0,69 en el psicológico y de 0,64 en el social. Conclusiones. El sistema de clasificación de niveles de deambulación funcional ofrece un marco para la evaluación conjunta de la deambulación y de los factores limitantes en la eficacia de un tratamiento. La concordancia interobservador avala iniciar su validación.

Mobility Analysis of AmpuTees (MAAT 4): classification tree analysis for probability of lower limb prosthesis user functional potential.

Purpose: To develop a predictive model to inform the probability of lower limb prosthesis users' functional potential for ambulation.Materials and Methods: A retrospective analysis of a database of outcomes for 2770 lower limb prosthesis users was used to inform a classification and regression tree analysis. Gender, age, height, weight, body mass index adjusted for amputation, amputation level, cause of amputation, comorbid health status and functional mobility score [Prosthetic Limb Users Survey of Mobility (PLUS-M™)] were entered as potential predictive variables. Patient K-Level was used to assign dependent variable status as unlimited community ambulator (i.e., K3 or K4) or limited community/household ambulator (i.e., K1 or K2). The classification tree was initially trained from 20% of the sample and subsequently tested with the remaining sample.Results: A classification tree was successfully developed, able to accurately classify 87.4% of individuals within the model's training group (standard error 1.4%), and 81.6% within the model's testing group (standard error 0.82%). Age, PLUS-M™ T-score, cause of amputation and body weight were retained within the tree logic.Conclusions: The resultant classification tree has the ability to provide members of the clinical care team with predictive probabilities of a patient's functional potential to help assist care decisions.Implications for RehabilitationClassification and regression tree analysis is a simple analytical tool that can be used to provide simple predictive models for patients with a lower limb prosthesis.The resultant classification tree had an 81.6% (standard error 0.82%) accuracy predicting functional potential as an unlimited community ambulator (i.e., K3 or K4) or limited community/ household ambulator (i.e., K1 or K2) in an unknown group of 2770 lower limb prosthesis users.The resultant classification tree can assist with the rehabilitation team's care planning providing probabilities of functional potential for the lower limb prosthesis user.

Association between ambulatory status and call bell use in hospitalized patients-A retrospective cohort study.

AIM: Characterize the relationship between patient ambulatory status and in-hospital call bell use. BACKGROUND: Although call bells are frequently used by patients to request help, the relationship between physical functioning and call bell use has not been evaluated. METHODS: Retrospective cohort study of 944 neuroscience patients hospitalized in a large academic urban medical centre between April 1, 2014 and August 1, 2014. We conducted multiple linear regression analyses with number of daily call bells from each patient as the primary outcome and patients' average ambulation status as the primary exposure variable. RESULTS: The mean number of daily call bell requests for all patients was 6.9 (6.1), for ambulatory patients 5.6 (4.8), and for non-ambulatory patients, it was 7.7 (6.6). Compared with non-ambulatory patients, ambulatory patients had a mean reduction in call bell use by 1.7 (95% CI 2.5 to -0.93, p < .001) calls per day. In a post hoc analysis, patients who could walk >250 feet had 5 fewer daily call bells than patients who were able to perform in-bed mobility. CONCLUSION: Ambulatory patients use their call bells less frequently than non-ambulatory patients. IMPLICATIONS FOR NURSING MANAGEMENT: Frequent use of call bells by non-ambulatory patients can place additional demands on nursing staff; patient mobility status should be considered in nurse workload/patient assignment.

Free-living Evaluation of Laboratory-based Activity Classifiers in Preschoolers.

Machine learning classification models for accelerometer data are potentially more accurate methods to measure physical activity in young children than traditional cut point methods. However, existing algorithms have been trained on laboratory-based activity trials, and their performance has not been investigated under free-living conditions. PURPOSE: This study aimed to evaluate the accuracy of laboratory-trained hip and wrist random forest and support vector machine classifiers for the automatic recognition of five activity classes: sedentary (SED), light-intensity activities and games (LIGHT_AG), walking (WALK), running (RUN), and moderate to vigorous activities and games (MV_AG) in preschool-age children under free-living conditions. METHODS: Thirty-one children (4.0 ± 0.9 yr) were video recorded during a 20-min free-living play session while wearing an ActiGraph GT3X+ on their right hip and nondominant wrist. Direct observation was used to continuously code ground truth activity class and specific activity types occurring within each class using a bespoke two-stage coding scheme. Performance was assessed by calculating overall classification accuracy and extended confusion matrices summarizing class-level accuracy and the frequency of specific activities observed within each class. RESULTS: Accuracy values for the hip and wrist random forest algorithms were 69.4% and 59.1%, respectively. Accuracy values for hip and wrist support vector machine algorithms were 66.4% and 59.3%, respectively. Compared with the laboratory cross validation, accuracy decreased by 11%-15% for the hip classifiers and 19%-21% for the wrist classifiers. Classification accuracy values were 72%-78% for SED, 58%-79% for LIGHT_AG, 71%-84% for MV_AG, 9%-15% for WALK, and 66%-75% for RUN. CONCLUSION: The accuracy of laboratory-based activity classifiers for preschool-age children was attenuated when tested on new data collected under free-living conditions. Future studies should train and test machine learning activity recognition algorithms using accelerometer data collected under free-living conditions.

The use of a pedometer to measure the physical activity during 12-hour shift of ICU and nurse anaesthetists in Poland.

BACKGROUND: Nurses are the largest group of employees in hospitals yet their working environment and conditions are not always optimal. Moreover, nurses may be convinced that the physical activity they perform during working hours is sufficient to maintain a healthy lifestyle. OBJECTIVES: The study aimed to measure the number of steps, the distance and the energy expenditure during a 12-hour shift in the intensive care unit and for nurse anaesthetists in selected hospitals in Poland. METHODS: Data were collected via a pedometer and a socio-demographic interview. The project was multicentre, data were collected from 11.11.2013 to 04.05.2014. RESULTS: The median number of steps taken by nurse anaesthetists within the operating room was 7404 (IQR 4461-9443) while in the ICU it was 7358 (IQR 4705-9101). During the day in the operating and recovery room, both nurse anaesthetists (IQR 3.90-6.26) and ICU nurses (IQR 3.54-6.39) reached the median distance of five kilometres. There were significant differences in the distance covered during day and night between ICU (p = 0.0003) and anaesthetic staff (p = 0.0001) as well as the number of steps (ICU p = 0.0002; ANEST p = 0.0001) and energy expenditure (ICU p = 0.0004; ANEST p = 0.0001). CONCLUSION: The professional activity of nurses alone is insufficient to meet the recommendation of taking 10,000 steps daily, which would contribute to improved quality of life.

Automatic Identification of Physical Activity Type and Duration by Wearable Activity Trackers: A Validation Study.

BACKGROUND: Activity trackers are now ubiquitous in certain populations, with potential applications for health promotion and monitoring and chronic disease management. Understanding the accuracy of this technology is critical to the appropriate and productive use of wearables in health research. Although other peer-reviewed validations have examined other features (eg, steps and heart rate), no published studies to date have addressed the accuracy of automatic activity type detection and duration accuracy in wearable trackers. OBJECTIVE: The aim of this study was to examine the ability of 4 commercially available wearable activity trackers (Fitbits Flex 2, Fitbit Alta HR, Fitbit Charge 2, and Garmin Vívosmart HR), in a controlled setting, to correctly and automatically identify the type and duration of the physical activity being performed. METHODS: A total of 8 activity types, including walking and running (on both a treadmill and outdoors), a run embedded in walking bouts, elliptical use, outdoor biking, and pool lap swimming, were tested by 28 to 34 healthy adult participants (69 total participants who participated in some to all activity types). Actual activity type and duration were recorded by study personnel and compared with tracker data using descriptive statistics and mean absolute percent error (MAPE). RESULTS: The proportion of trials in which the activity type was correctly identified was 93% to 97% (depending on the tracker) for treadmill walking, 93% to 100% for treadmill running, 36% to 62% for treadmill running when preceded and followed by a walk, 97% to 100% for outdoor walking, 100% for outdoor running, 3% to 97% for using an elliptical, 44% to 97% for biking, and 87.5% for swimming. When activities were correctly identified, the MAPE of the detected duration versus the actual activity duration was between 7% and 7.9% for treadmill walking, 8.7% and 144.8% for treadmill running, 23.6% and 28.9% for treadmill running when preceded and followed by a walk, 4.9% and 11.8% for outdoor walking, 5.6% and 9.6% for outdoor running, 9.7% and 13% for using an elliptical, 9.5% and 17.7% for biking, and was 26.9% for swimming. CONCLUSIONS: In a controlled setting, wearable activity trackers provide accurate recognition of the type of some common physical activities, especially outdoor walking and running and walking on a treadmill. The accuracy of measurement of activity duration varied considerably by activity type and tracker model and was poor for complex sets of activity, such as a run embedded within 2 walking segments.

The Dynamic Baropodometric Profile of Children with Idiopathic Toe-Walking A Cross-Sectional Study.

BACKGROUND: Idiopathic toe-walking (ITW) gait may present in children older than 3 years and in the absence of a medical condition known to cause or be associated with toe-walking gait. It is unknown how this gait type changes pressure distribution in the growing foot. We sought to determine whether children with ITW gait exhibit different plantar pressures and temporal gait features than typically developing children. METHODS: Children aged 3 to 6 years were recruited who had either a typical heel-toe gait pattern or a diagnosis of ITW. The ITW diagnosis was reported by the parent/caregiver and confirmed through history and physical examination. Temporal gait measures, peak pressures, and impulse percentages were measured. A minimum of ten unshod footprints were collected. Data were compared with unpaired t tests. RESULTS: The study included 40 children with typical gait and 56 with ITW gait. The ITW group displayed lower peak pressures at the hallux, midfoot, and hindfoot ( P < .05) and higher and lower pressure impulse percentages at the forefoot ( P < .001) and hindfoot ( P < .001), respectively. The ITW group spent a higher percentage of contact time at all areas of the forefoot and less at the midfoot and rearfoot ( P < .05). There were no significant differences in total step duration and foot progression angle between groups ( P > .05). CONCLUSIONS: There were differences in pressure distributions between groups. Understanding these differences may help us better understand the compensations or potential long-term impact that ITW gait may have on a young child's foot. Podiatric physicians may also consider the use of this equipment in the clinical setting to measure outcomes after treatment for ITW.

A Novel Accelerometer-Based Technique for Robust Detection of Walking Direction.

OBJECTIVE: Distance estimation in pedestrian dead reckoning is acquired using vector norm of accelerations, which results in positive values. However, anteroposterior acceleration is negative when a step is taken backward, which must be detected for accurate localization. This paper proposes a novel approach for the detection of walking direction, which uses a dominant trend duration. METHODS: The approach evaluates anteroposterior acceleration out of a foot-worn accelerometer for temporal dominance of acceleration trends during swing phase of the walk. The approach is tested for forward and backward walks with speed variations on a straight path as well as for forward walk at normal speed on a turning path. To validate the detection accuracy, success rates per participant per walk trial are calculated and then overall success rate for all the trials are reported. Moreover, metrics precision, recall and F1 scores are calculated for detection reliability in both directions. RESULTS: Overall 98 ± 2% detection accuracy is achieved on linear path considering both directions and all speed variations, whereas 93 ± 7% on turning path including left and right turns. In comparison with the state-of-the-art bidirectional detection approach, the proposed approach delivers accurate detection with speed variations without requiring prior training and relies on a single sensory feature. CONCLUSION: Dominant trend duration is a novel and reliable feature to detect directional changes during communal walk with speed variation. SIGNIFICANCE: The approach can be employed in different contexts, such as enabling pedestrian localization approaches to accommodate back stepping or any application that requires knowledge of changing directions while walking.

Wandering Pattern Sensing at S-Band.

Increasing prevalence of dementia has posed several challenges for care-givers. Patients suffering from dementia often display wandering behavior due to boredom or memory loss. It is considered to be one of the challenging conditions to manage and understand. Traits of dementia patients can compromise their safety causing serious injuries. This paper presents investigation into the design and evaluation of wandering scenarios with patients suffering from dementia using an S-band sensing technique. This frequency band is the wireless channel commonly used to monitor and characterize different scenarios including random, lapping, and pacing movements in an indoor environment. Wandering patterns are characterized depending on the received amplitude and phase information of that measures the disturbance caused in the ideal radio signal. A secondary analysis using support vector machine is used to classify the three patterns. The results show that the proposed technique carries high classification accuracy up to 90% and has good potential for healthcare applications.

Identifying the effects of using integrated haptic feedback for gait rehabilitation of stroke patients.

This paper evaluates the prospects of using a novel Integrated Haptic Feedback (IHF) system. IHF can provide over-ground gait training regimens for post-stroke ambulatory subjects. IHF system combines the use of a portable cane for kinesthetic feedback and a wearable vibrotactor array for tactile feedback. Continuous somatosensory input is aiforded to the users at the handle of cane; it serves the purpose of balance assurance at higher gait speeds. Besides, restricted use of upper limb for weight-bearing inspires the users to involve the paretic lower limbs more actively. Furthermore, tactile feedback contributes in enhancing the gait symmetry through afferent signal of vibration. Six post-stroke ambulatory individuals participated in walking trials to identity the effects of IHF system. Results indicate that while walking faster patients' body sway was not disturbed. Statistically significant increase was observed in temporal stance symmetry (p-value=0.02) and in paretic muscle (vastus medialis obliquus and semitendinosus) activation during stance phase (p-value<0.01). The IHF system can be a valuable tool to assist physical therapist in gait rehabilitation of post-stroke individuals.

Literature Review of Idiopathic Toe Walking: Etiology, Prevalence, Classification, and Treatment.

PURPOSE: The main objective of this review is to gather the information available about idiopathic toe walking (ITW), its prevalence and classification, and possible therapeutic approaches. In addition, this review aims to clarify the differences between idiopathic toe walkers and tiptoe walkers with underlying neurological or muscle deficiency as primary conditions. Understanding its causes and learning to make a differential diagnosis will help determine the adequate therapeutic approach. METHODS: This is a review of different articles and case studies from 1967 to 2016. The information was gathered to update and unify all the information about ITW that has been published. CONCLUSION: The literature offers limited research regarding the possible etiology, prevalence, classification, and evaluation of ITW. This review puts together all the information regarding the etiology, prevalence, classifications, evaluation, and treatment of ITW. LEVELS OF EVIDENCE: Level IV.

Mechanical energy patterns in nordic walking: comparisons with conventional walking.

The use of poles during Nordic Walking (NW) actively engages the upper body to propel the body forward during walking. Evidence suggests that NW leads to a longer stride and higher speed, and sometimes to increased ground reaction forces with respect to conventional walking (W). The aim of this study was to investigate if NW is associated with different changes in body centre of mass (COM) motion and limbs energy patterns, mechanical work and efficiency compared to W. Eight experienced Nordic Walkers performed 5-min W and NW trials on a treadmill at 4kmh-1. Steady state oxygen consumption and movements of body segments and poles were measured during each trial. We found greater fluctuation of kinetic (KE) and potential (PE) energy associated with COM displacement for NW compared to W. An earlier increase of KE for NW than for W, probably due to the propulsive action of poles, modified the synchronization between PE and KE oscillations so that a 10.9% higher pendular recovery between these energies was found in NW. The 10.2% higher total mechanical work found for NW was mainly due to the greater work required to move upper limbs and poles. NW was 20% less efficient and was metabolically more demanding than W, this difference could be ascribed to isometric contraction and low efficiency of upper musculature. Concluding, NW can be considered a highly dynamic gait, with distinctive mechanical features compared to conventional gait, due to pole propulsion and arm/pole swing.

Classification of Movement of People with Parkinsons Disease Using Wearable Inertial Movement Units and Machine Learning.

In this work, inertial movement units were placed on people with Parkinsons disease (PwPD) who subsequently performed a standard test of walking endurance (six-minute walk test - 6MWT). Five devices were placed on each the limbs and small of the back. These devices captured the acceleration and rotational motion while the person walked as far as they can in six minutes. The wearable devices can objectively indicate the pattern and rhythmicity of limb and body movements. It is possible that this data, when subject to machine learning could provide additional objective measures that may support clinical observations related to the quality of movement. The aim of this work is two fold. First, to identify the most useful features of the captured signals; second, to identify the accuracy of using these features to predict the severity of PD as measured by standard clinical assessment.

Treadmill measures of ambulation rates in ovine models of spinal cord injury and neuropathic pain.

Our laboratories are developing treadmill-based gait analysis employing sheep to investigate potential efficacy of intra-dural spinal cord stimulation in the treatment of spinal cord injury and neuropathic pain. As part of efforts to establish the performance characteristics of the experimental arrangement, this study measured the treadmill speed via a tachometer, video belt-marker timing and ambulation-rate observations of the sheep. The data reveal a 0.1-0.3% residual drift in the baseline (unloaded) treadmill speed which increases with loading, but all three approaches agree on final speed to within 1.7%, at belt speeds of ≈ 4 km/h. Using the tachometer as the standard, the estimated upper limit on uncertainty in the video belt-marker approach is ± 0.18 km h(-1) and the measured uncertainty is ± 0.15 km h(-1). Employment of the latter method in determining timing differences between contralateral hoof strikes by the sheep suggests its utility in assessing severity of SCI and responses to therapeutic interventions.

The Walking Speed Questionnaire: Assessing Walking Speed in a Self-reported Format.

OBJECTIVES: The literature increasingly demonstrates the importance of gait speed (GS) in the frailty assessment of patients aged 60 years and older. Conventional GS measurement, however, maybe contraindicated in settings such as trauma where the patient is temporarily immobilized. We devised a Walking Speed Questionnaire (WSQ) to allow assessment of preinjury baseline GS, in meters per second, in a self-reported manner, to overcome the inability to directly test the patients' walking speed. DESIGN: Four questions comprise the WSQ, and were derived using previously published questionnaires and expert opinion of 6 physician-researchers. SETTING: Four ambulatory clinics. PARTICIPANTS: Ambulating individuals aged 60-95 (mean age, 73.2 ± 8.1 years, 86.1% female, n = 101). INTERVENTION: Participants completed the WSQ and underwent GS measurement for comparison. ANALYSIS: WSQ score correlation to true GS, receiver operating characteristics, and validation statistics were performed. RESULTS: All 4 questions of the WSQ independently predicted true GS significantly (P < 0.001). The WSQ sufficiently predicted true GS with r = 0.696 and ρ = 0.717. CONCLUSIONS: The WSQ is an effective tool for assessing baseline walking speed in patients aged 60 years and older in a self-reported manner. It permits gait screening in health care environments where conventional GS testing is contraindicated due to temporary immobilization and maybe used to provide baseline targets for goal-oriented post-trauma care. Given its ability to capture GS in patients who are unable to ambulate, it may open doors for frailty research in previously unattainable populations. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Exploring Muscle Activation during Nordic Walking: A Comparison between Conventional and Uphill Walking.

Nordic Walking (NW) owes much of its popularity to the benefits of greater energy expenditure and upper body engagement than found in conventional walking (W). Muscle activation during NW is still understudied, however. The aim of the present study was to assess differences in muscle activation and physiological responses between NW and W in level and uphill walking conditions. Nine expert Nordic Walkers (mean age 36.8±11.9 years; BMI 24.2±1.8 kg/m2) performed 5-minute treadmill trials of W and NW at 4 km/h on inclines of 0% and 15%. The electromyographic activity of seven upper body and five leg muscles and oxygen consumption (VO2) were recorded and pole force during NW was measured. VO2 during NW was 22.3% higher at 0% and only 6.9% higher at 15% than during W, while upper body muscle activation was 2- to 15-fold higher under both conditions. Lower body muscle activation was similarly increased during NW and W in the uphill condition, whereas the increase in erector spinae muscle activity was lower during NW than W. The lack of a significant increase in pole force during uphill walking may explain the lower extra energy expenditure of NW, indicating less upper body muscle activation to lift the body against gravity. NW seemed to reduce lower back muscle contraction in the uphill condition, suggesting that walking with poles may reduce effort to control trunk oscillations and could contribute to work production during NW. Although the difference in extra energy expenditure between NW and W was smaller in the uphill walking condition, the increased upper body muscle involvement during exercising with NW may confer additional benefit compared to conventional walking also on uphill terrains. Furthermore, people with low back pain may gain benefit from pole use when walking uphill.

Gait velocity and walking distance to predict community walking after stroke.

Gait speed and walking distance were evaluated as predictors for levels of community walking after stroke. In this study, 103 stroke survivors were identified as limited (n = 67) or independent community walkers (n = 36). Ten meter and six min walk tests were used to measure gait speed and walking distance, respectively. The discriminative properties of gait speed and walking distance for community walking were investigated using receiver operating characteristic curves. Cut-off values of 0.87 m/s for community walking gait speed for walking distance had positive predictive values of 65% and 55%, respectively. The negative predictive value ranged from 89% for gait speed to 79% for walking distance. Gait speed and walking distance showed significant differences between limited and independent community walking. Gait speed was more significantly related to community walking than walking distance. The results of this study suggest that gait speed is a better predictor for community walking than walking distance in moderately affected post-stroke survivors.

Joints and their relations as critical features in action discrimination: evidence from a classification image method.

Classifying an action as a runner or a walker is a seemingly effortless process. However, it is difficult to determine which features are used with hypothesis-driven research, because biological motion stimuli generally consist of about a dozen joints, yielding an enormous number of potential relationships among them. Here, we develop a hypothesis-free approach based on a classification image method, using experimental data from relatively few trials (∼1,000 trials per subject). Employing ambiguous actions morphed between a walker and a runner, we identified three types of features that play important roles in discriminating bipedal locomotion presented in a side view: (a) critical joint feature, supported by the finding that the similarity of the movements of feet and wrists to prototypical movements of these joints were most reliably used across all participants; (b) structural features, indicated by contributions from almost all other joints, potentially through a form-based analysis; and (c) relational features, revealed by statistical correlations between joint contributions, specifically relations between the two feet, and relations between the wrists/elbow and the hips. When the actions were inverted, only critical joint features remained to significantly influence discrimination responses. When actions were presented with continuous depth rotation, critical joint features and relational features associated strongly with responses. Using a double-pass paradigm, we estimated that the internal noise is about twice as large as the external noise, consistent with previous findings. Overall, our novel design revealed a rich set of critical features that are used in action discrimination. The visual system flexibly selects a subset of features depending on viewing conditions.