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Sample records for 6-minute walk test

  1. The 6-minute walk test as a new outcome measure in Duchenne muscular dystrophy.

    PubMed

    McDonald, Craig M; Henricson, Erik K; Han, Jay J; Abresch, R Ted; Nicorici, Alina; Elfring, Gary L; Atkinson, Leone; Reha, Allen; Hirawat, Samit; Miller, Langdon L

    2010-04-01

    Walking abnormalities are prominent in Duchenne muscular dystrophy (DMD). We modified the 6-minute walk test (6MWT) for use as an outcome measure in patients with DMD and evaluated its performance in 21 ambulatory boys with DMD and 34 healthy boys, ages 4 to 12 years. Boys with DMD were tested twice, approximately 1 week apart; controls were tested once. The groups had similar age, height, and weight. All tests were completed. Boys who fell recovered rapidly from falls without injury. Mean +/- SD [range] 6-minute walk distance (6MWD) was lower in boys with DMD than in controls (366 +/- 83 [125-481] m vs. 621 +/- 68 [479-754] m; P < 0.0001; unpaired t-test). Test-retest correlation for boys with DMD was high (r = 0.91). Stride length (R(2) = 0.89; P < 0.0001) was the major determinant of 6MWD for both boys with DMD and controls. A modified 6MWT is feasible and safe, documents disease-related limitations on ambulation, is reproducible, and offers a new outcome measure for DMD natural history and therapeutic trials.

  2. Strong correlation between the 6-minute walk test and accelerometry functional outcomes in boys with Duchenne muscular dystrophy.

    PubMed

    Davidson, Zoe E; Ryan, Monique M; Kornberg, Andrew J; Walker, Karen Z; Truby, Helen

    2015-03-01

    Accelerometry provides information on habitual physical capability that may be of value in the assessment of function in Duchenne muscular dystrophy. This preliminary investigation describes the relationship between community ambulation measured by the StepWatch activity monitor and the current standard of functional assessment, the 6-minute walk test, in ambulatory boys with Duchenne muscular dystrophy (n = 16) and healthy controls (n = 13). All participants completed a 6-minute walk test and wore the StepWatch™ monitor for 5 consecutive days. Both the 6-minute walk test and StepWatch accelerometry identified a decreased capacity for ambulation in boys with Duchenne compared to healthy controls. There were strong, significant correlations between 6-minute walk distance and all StepWatch parameters in affected boys only (r = 0.701-0.804). These data proffer intriguing observations that warrant further exploration. Specifically, accelerometry outcomes may compliment the 6-minute walk test in assessment of therapeutic interventions for Duchenne muscular dystrophy.

  3. The 6 minute walk test and performance of upper limb in ambulant duchenne muscular dystrophy boys.

    PubMed

    Pane, Marika; Mazzone, Elena Stacy; Sivo, Serena; Fanelli, Lavinia; De Sanctis, Roberto; D'Amico, Adele; Messina, Sonia; Battini, Roberta; Bianco, Flaviana; Scutifero, Marianna; Petillo, Roberta; Frosini, Silvia; Scalise, Roberta; Vita, Gian Luca; Bruno, Claudio; Pedemonte, Marina; Mongini, Tiziana; Pegoraro, Elena; Brustia, Francesca; Gardani, Alice; Berardinelli, Angela; Lanzillotta, Valentina; Viggiano, Emanuela; Cavallaro, Filippo; Sframeli, Maria; Bello, Luca; Barp, Andrea; Busato, Fabio; Bonfiglio, Serena; Rolle, Enrica; Colia, Giulia; Bonetti, Annamaria; Palermo, Concetta; Graziano, Alessandra; D'Angelo, Grazia; Pini, Antonella; Corlatti, Alice; Gorni, Ksenija; Baranello, Giovanni; Antonaci, Laura; Bertini, Enrico; Politano, Luisa; Mercuri, Eugenio

    2014-10-07

    The Performance of Upper Limb (PUL) test was specifically developed for the assessment of upper limbs in Duchenne muscular dystrophy (DMD). The first published data have shown that early signs of involvement can also be found in ambulant DMD boys. The aim of this longitudinal Italian multicentric study was to evaluate the correlation between the 6 Minute Walk Test (6MWT) and the PUL in ambulant DMD boys. Both 6MWT and PUL were administered to 164 ambulant DMD boys of age between 5.0 and 16.17 years (mean 8.82). The 6 minute walk distance (6MWD) ranged between 118 and 557 (mean: 376.38, SD: 90.59). The PUL total scores ranged between 52 and 74 (mean: 70.74, SD: 4.66). The correlation between the two measures was 0.499. The scores on the PUL largely reflect the overall impairment observed on the 6MWT but the correlation was not linear. The use of the PUL appeared to be less relevant in the very strong patients with 6MWD above 400 meters, who, with few exceptions had near full scores. In patients with lower 6MWD the severity of upper limb involvement was more variable and could not always be predicted by the 6MWD value or by the use of steroids. Our results confirm that upper limb involvement can already be found in DMD boys even in the ambulant phase.

  4. The 6 Minute Walk Test and Performance of Upper Limb in Ambulant Duchenne Muscular Dystrophy Boys

    PubMed Central

    Pane, Marika; Mazzone, Elena Stacy; Sivo, Serena; Fanelli, Lavinia; De Sanctis, Roberto; D’Amico, Adele; Messina, Sonia; Battini, Roberta; Bianco, Flaviana; Scutifero, Marianna; Petillo, Roberta; Frosini, Silvia; Scalise, Roberta; Vita, Gian Luca; Bruno, Claudio; Pedemonte, Marina; Mongini, Tiziana; Pegoraro, Elena; Brustia, Francesca; Gardani, Alice; Berardinelli, Angela; Lanzillotta, Valentina; Viggiano, Emanuela; Cavallaro, Filippo; Sframeli, Maria; Bello, Luca; Barp, Andrea; Busato, Fabio; Bonfiglio, Serena; Rolle, Enrica; Colia, Giulia; Bonetti, Annamaria; Palermo, Concetta; Graziano, Alessandra; D’Angelo, Grazia; Pini, Antonella; Corlatti, Alice; Gorni, Ksenija; Baranello, Giovanni; Antonaci, Laura; Bertini, Enrico; Politano, Luisa; Mercuri, Eugenio

    2014-01-01

    The Performance of Upper Limb (PUL) test was specifically developed for the assessment of upper limbs in Duchenne muscular dystrophy (DMD). The first published data have shown that early signs of involvement can also be found in ambulant DMD boys. The aim of this longitudinal Italian multicentric study was to evaluate the correlation between the 6 Minute Walk Test (6MWT) and the PUL in ambulant DMD boys. Both 6MWT and PUL were administered to 164 ambulant DMD boys of age between 5.0 and 16.17 years (mean 8.82). The 6 minute walk distance (6MWD) ranged between 118 and 557 (mean: 376.38, SD: 90.59). The PUL total scores ranged between 52 and 74 (mean: 70.74, SD: 4.66). The correlation between the two measures was 0.499. The scores on the PUL largely reflect the overall impairment observed on the 6MWT but the correlation was not linear. The use of the PUL appeared to be less relevant in the very strong patients with 6MWD above 400 meters, who, with few exceptions had near full scores. In patients with lower 6MWD the severity of upper limb involvement was more variable and could not always be predicted by the 6MWD value or by the use of steroids. Our results confirm that upper limb involvement can already be found in DMD boys even in the ambulant phase. PMID:25642376

  5. Factors associated with the 6-minute walk test in nursing home residents and community-dwelling older adults

    PubMed Central

    Caballer, Vicent-Benavent; Lisón, Juan Francisco; Rosado-Calatayud, Pedro; Amer-Cuenca, Juan José; Segura-Orti, Eva

    2015-01-01

    [Purpose] The main objective of this study was to determine the contributions and extent to which certain physical measurements explain performance in the 6-minute walk test in healthy older adults living in a geriatric nursing home and for older adults dwelling in the community. [Subjects] The subjects were 122 adults aged 65 and older with no cognitive impairment who were independent in their daily activities. [Methods] The 6-minute walk test, age, body mass index, walking speed, chair stand test, Berg Balance Scale, Timed Up-and-Go test, rectus femoris cross-sectional area, Short Physical Performance Battery, and hand-grip strength were examined. [Results] Strong significant associations were found between mobility, lower-limb function, balance, and the 6-minute walk test. A stepwise multiple regression on the entire sample showed that lower-limb function was a significant and independent predictor for the 6-minute walk test. Additionally, lower-limb function was a strong predictor for the 6-minute walk test in our nursing home group, whereas mobility was found to be the best predictor in our community-dwelling group. [Conclusion] Better lower-limb function, balance, and mobility result in a higher distance covered by healthy older adults. Lower-limb function and mobility appeared to best determine walking performance in the nursing home and community-dwelling groups, respectively. PMID:26696740

  6. 6 Minute Walk Test in Duchenne MD Patients with Different Mutations: 12 Month Changes

    PubMed Central

    Pane, Marika; Mazzone, Elena S.; Sormani, Maria Pia; Messina, Sonia; Vita, Gian Luca; Fanelli, Lavinia; Berardinelli, Angela; Torrente, Yvan; D'Amico, Adele; Lanzillotta, Valentina; Viggiano, Emanuela; D'Ambrosio, Paola; Cavallaro, Filippo; Frosini, Silvia; Bello, Luca; Bonfiglio, Serena; Scalise, Roberta; De Sanctis, Roberto; Rolle, Enrica; Bianco, Flaviana; Van der Haawue, Marlene; Magri, Francesca; Palermo, Concetta; Rossi, Francesca; Donati, Maria Alice; Alfonsi, Chiara; Sacchini, Michele; Arnoldi, Maria Teresa; Baranello, Giovanni; Mongini, Tiziana; Pini, Antonella; Battini, Roberta; Pegoraro, Elena; Previtali, Stefano C.; Napolitano, Sara; Bruno, Claudio; Politano, Luisa; Comi, Giacomo P.; Bertini, Enrico; Morandi, Lucia; Gualandi, Francesca; Ferlini, Alessandra; Goemans, Nathalie; Mercuri, Eugenio

    2014-01-01

    Objective In the last few years some of the therapeutical approaches for Duchenne muscular dystrophy (DMD) are specifically targeting distinct groups of mutations, such as deletions eligible for skipping of individual exons. The aim of this observational study was to establish whether patients with distinct groups of mutations have different profiles of changes on the 6 minute walk test (6MWT) over a 12 month period. Methods The 6MWT was performed in 191 ambulant DMD boys at baseline and 12 months later. The results were analysed using a test for heterogeneity in order to establish possible differences among different types of mutations (deletions, duplications, point mutations) and among subgroups of deletions eligible to skip individual exons. Results At baseline the 6MWD ranged between 180 and 560,80 metres (mean 378,06, SD 74,13). The 12 month changes ranged between −325 and 175 (mean −10.8 meters, SD 69.2). Although boys with duplications had better results than those with the other types of mutations, the difference was not significant. Similarly, boys eligible for skipping of the exon 44 had better baseline results and less drastic changes than those eligible for skipping exon 45 or 53, but the difference was not significant. Conclusions even if there are some differences among subgroups, the mean 12 month changes in each subgroup were all within a narrow Range: from the mean of the whole DMD cohort. This information will be of help at the time of designing clinical trials with small numbers of eligible patients. PMID:24421885

  7. Test-Retest Reliability of the 10-Metre Fast Walk Test and 6-Minute Walk Test in Ambulatory School-Aged Children with Cerebral Palsy

    ERIC Educational Resources Information Center

    Thompson, Patricia; Beath, Tricia; Bell, Jacqueline; Jacobson, Gabrielle; Phair, Tegan; Salbach, Nancy M.; Wright, F. Virginia

    2008-01-01

    Short-term test-retest reliability of the 10-metre fast walk test (10mFWT) and 6-minute walk test (6MWT) was evaluated in 31 ambulatory children with cerebral palsy (CP), with subgroup analyses in Gross Motor Function Classification System (GMFCS) Levels I (n=9), II (n=8), and III (n=14). Sixteen females and 15 males participated, mean age 9 years…

  8. The 6-minute walk test in Duchenne/Becker muscular dystrophy: longitudinal observations.

    PubMed

    McDonald, Craig M; Henricson, Erik K; Han, Jay J; Abresch, R Ted; Nicorici, Alina; Atkinson, Leone; Elfring, Gary L; Reha, Allen; Miller, Langdon L

    2010-12-01

    In this study we used the 6-minute walk distance (6MWD) to characterize ambulation over time in Duchenne/Becker muscular dystrophy (DBMD). The 6MWD was assessed in 18 boys with DBMD and 22 healthy boys, ages 4-12 years, over mean [range] intervals of 58 [39-87] and 69 [52-113] weeks, respectively. Height and weight increased similarly in both groups. At 52 weeks, 6MWD decreased in 12 of 18 (67%) DBMD subjects (overall mean [range]: 357 [125-481] to 300 [0-510] meters; Δ -57 meters, -15.9%), but increased in 14 of 22 (64%) healthy subjects (overall mean [range]: 623 [479-754] to 636 [547-717] meters; Δ +13 meters, +2.1%). Two DBMD subjects lost ambulation. Changes in 6MWD depended on stride length and age; improvements usually occurred by 7-8 years of age; older DBMD subjects worsened, whereas older healthy subjects were stable. The 6MWD changes at 1 year confirm the validity of this endpoint and emphasize that preserving ambulation must remain a major goal of DBMD therapy.

  9. Are the average gait speeds during the 10meter and 6minute walk tests redundant in Parkinson disease?

    PubMed

    Duncan, Ryan P; Combs-Miller, Stephanie A; McNeely, Marie E; Leddy, Abigail L; Cavanaugh, James T; Dibble, Leland E; Ellis, Terry D; Ford, Matthew P; Foreman, K Bo; Earhart, Gammon M

    2017-02-01

    We investigated the relationships between average gait speed collected with the 10Meter Walk Test (Comfortable and Fast) and 6Minute Walk Test (6MWT) in 346 people with Parkinson disease (PD) and how the relationships change with increasing disease severity. Pearson correlation and linear regression analyses determined relationships between 10Meter Walk Test and 6MWT gait speed values for the entire sample and for sub-samples stratified by Hoehn & Yahr (H&Y) stage I (n=53), II (n=141), III (n=135) and IV (n=17). We hypothesized that redundant tests would be highly and significantly correlated (i.e. r>0.70, p<0.05) and would have a linear regression model slope of 1 and intercept of 0. For the entire sample, 6MWT gait speed was significantly (p<0.001) related to the Comfortable 10 Meter Walk Test (r=0.75) and Fast 10Meter Walk Test (r=0.79) gait speed, with 56% and 62% of the variance in 6MWT gait speed explained, respectively. The regression model of 6MWT gait speed predicted by Comfortable 10 Meter Walk gait speed produced slope and intercept values near 1 and 0, respectively, especially for participants in H&Y stages II-IV. In contrast, slope and intercept values were further from 1 and 0, respectively, for the Fast 10Meter Walk Test. Comfortable 10 Meter Walk Test and 6MWT gait speeds appeared to be redundant in people with moderate to severe PD, suggesting the Comfortable 10 Meter Walk Test can be used to estimate 6MWT distance in this population.

  10. Comparison between the 6-minute walk tests performed in patients with chronic obstructive pulmonary disease at different altitudes

    PubMed Central

    Squassoni, Selma Denis; Machado, Nadine Cristina; Lapa, Mônica Silveira; Cordoni, Priscila Kessar; Bortolassi, Luciene Costa; de Oliveira, Juliana Nascimento; Tavares, Cecilia Melo Rosa; Fiss, Elie

    2014-01-01

    Objective To evaluate the influence of the altitude on the 6-minute walking test in patients with moderate to severe pulmonary disease. Methods Twenty-nine patients performed the 6-minute walk test at a pulmonary rehabilitation clinic in Santo André (above sea level), in São Paulo State, and at the Enseada Beach, in Guarujá (at sea level), also in São Paulo State. Of these 29 patients, 8 did the test both on hard sand and on asphalt to analyze if there were differences in performance during the tests. Data such as heart rate, oxygen saturation, test distance, and Borg scale were compared. Results We found no statistical difference in relation to oxygen saturation at rest before the beginning of the walking test in Santo André 94.67±2.26% and at sea level 95.56±2% (p=0.71). The minimum saturation measured during the test was 87.27±6.54% in Santo André and 89.10±5.41% in Guarujá (p=0.098). There were no differences in the performed distance between the different kinds of terrains; the distance on sand was 387.75±5.02m and on asphalt it was 375.00±6.54m (p=0.654). Regarding oxygen saturation during walking, the pulse oximetry on sand was 95.12±1.80% and on asphalt it was 96.87±1.64% (p=1.05). Conclusion Altitude did not affect the performance of the walking test in patients with moderate to severe pulmonary disease and the results were similar in both cases, on sand and on asphalt. PMID:25628195

  11. The 6-minute walk test in female fibromyalgia patients: relationship with tenderness, symptomatology, quality of life, and coping strategies.

    PubMed

    Carbonell-Baeza, Ana; Ruiz, Jonatan R; Aparicio, Virginia A; Ortega, Francisco B; Delgado-Fernández, Manuel

    2013-12-01

    The purpose of this study was to examine the relationship between the 6-minute walk test (6-MWT) and tenderness, symptomatology, quality of life, and coping strategies in women with fibromyalgia. One hundred eighteen women with fibromyalgia aged 51.9 ± 7.3 years participated in the study. The examination included the 6-MWT, tender points, and the following questionnaires: Fibromyalgia Impact Questionnaire (FIQ), Short-Form Health Survey 36 (SF-36), and Vanderbilt Pain Management Inventory. Fair correlations between the 6-MWT and the subscales of physical impairment (FIQ) and physical function (SF-36) were observed (ρ -0.365 and 0.347, respectively, both p < .001). The 6-MWT showed a weak relationship with tenderness (ρ 0.201 and -0.191 for algometer score and tender points count, respectively, both p < .05). The relationship between the 6-MWT and global score of FIQ, and FIQ subscales of pain and fatigue were weak (ρ -0.201, -0.211, and -0.226, respectively, all p < .05). The 6-MWT showed a weak relationship with bodily pain and vitality scales of SF-36 (ρ 0.256 and 0.258, respectively, both p = .005) and with passive and active coping strategies (ρ -0.255 and 0.223, both p < .05). This study in women with fibromyalgia shows significant relationships, ranging from weak to fair, between the 6-MWT and tenderness, symptomatology, quality of life, and coping strategies. These findings indicate that functional capacity, as assessed by the distance walked in 6 minutes, might be important when planning the assessment, treatment, and monitoring of patients with fibromyalgia.

  12. Usefulness of the 6-minute walk test as a screening test for pulmonary arterial enlargement in COPD

    PubMed Central

    Oki, Yutaro; Kaneko, Masahiro; Fujimoto, Yukari; Sakai, Hideki; Misu, Shogo; Mitani, Yuji; Yamaguchi, Takumi; Yasuda, Hisafumi; Ishikawa, Akira

    2016-01-01

    Purpose Pulmonary hypertension and exercise-induced oxygen desaturation (EID) influence acute exacerbation of COPD. Computed tomography (CT)-detected pulmonary artery (PA) enlargement is independently associated with acute COPD exacerbations. Associations between PA to aorta (PA:A) ratio and EID in patients with COPD have not been reported. We hypothesized that the PA:A ratio correlated with EID and that results of the 6-minute walk test (6MWT) would be useful for predicting the risk associated with PA:A >1. Patients and methods We retrospectively measured lung function, 6MWT, emphysema area, and PA enlargement on CT in 64 patients with COPD. The patients were classified into groups with PA:A ≤1 and >1. Receiver-operating characteristic curves were used to determine the threshold values with the best cutoff points to predict patients with PA:A >1. Results The PA:A >1 group had lower forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1:FVC ratio, diffusion capacity of lung carbon monoxide, 6MW distance, and baseline peripheral oxygen saturation (SpO2), lowest SpO2, highest modified Borg scale results, percentage low-attenuation area, and history of acute COPD exacerbations ≤1 year, and worse BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise) index results (P<0.05). Predicted PA:A >1 was determined for SpO2 during 6MWT (best cutoff point 89%, area under the curve 0.94, 95% confidence interval 0.88–1). SpO2 <90% during 6MWT showed a sensitivity of 93.1, specificity of 94.3, positive predictive value of 93.1, negative predictive value of 94.3, positive likelihood ratio of 16.2, and negative likelihood ratio of 0.07. Conclusion Lowest SpO2 during 6MWT may predict CT-measured PA:A, and lowest SpO2 <89% during 6MWT is excellent for detecting pulmonary hypertension in COPD. PMID:27920514

  13. Assessing Walking Ability in People with HTLV-1-Associated Myelopathy Using the 10 Meter Timed Walk and the 6 Minute Walk Test

    PubMed Central

    Adonis, Adine; Taylor, Graham P.

    2016-01-01

    Background Five to ten million persons, are infected by HTLV-1 of which 3% will develop HTLV-1-associated myelopathy (HAM) a chronic, disabling inflammation of the spinal cord. Walking, a fundamental, complex, multi-functional task is demanding of multiple body systems. Restricted walking ability compromises activity and participation levels in people with HAM (pwHAM). Therapy aims to improve mobility but validated measures are required to assess change. Study Design Prospective observational study. Objectives To explore walking capacity in pwHAM, walking endurance using the 6 minute walk (6MW), and gait speed, using the timed 10m walk (10mTW). Setting Out-patient setting in an inner London Teaching hospital. Methods Prospective documentation of 10mTW and 6MW distance; walking aid usage and pain scores measured twice, a median of 18 months apart. Results Data analysis was completed for twenty-six pwHAM, (8♂; 18♀; median age: 57.8 years; median disease duration: 8 years). Median time at baseline to: complete 10m was 17.5 seconds, versus 21.4 seconds at follow up; 23% completed the 6MW compared to 42% at follow up and a median distance of 55m was covered compared to 71m at follow up. Using the 10mTW velocity to predict the 6MW distance, overestimated the distance walked in 6 minutes (p<0.01). Functional decline over time was captured using the functional ambulation categories. Conclusions The 10mTW velocity underestimated the degree of disability. Gait speed usefully predicts functional domains, shows direction of functional change and comparison with published healthy age matched controls show that these patients have significantly slower gait speeds. The measured differences over 18 months were sufficient to reliably detect change and therefore these assessments can be useful to detect improvement or deterioration within broader disability grades. Walking capacity in pwHAM should be measured using the 10mTW for gait speed and the 6MW for endurance. PMID

  14. An Evaluation of Prediction Equations for the 6 Minute Walk Test in Healthy European Adults Aged 50-85 Years

    PubMed Central

    Duncan, Michael J.; Mota, Jorge; Carvalho, Joana; Nevill, Alan M.

    2015-01-01

    Objective This study compared actual 6 minute walk test (6MWT) performance with predicted 6MWT using previously validated equations and then determined whether allometric modelling offers a sounder alternative to estimating 6MWT in adults aged 50–80 years. Methods We compared actual 6MWT performance against predicted 6MWT in 125 adults aged 50–85 years (62 male, 63 female). In a second sample of 246 adults aged 50–85 years (74 male, 172 female), a new prediction equation for 6MWT performance was developed using allometric modelling. This equation was then cross validated using the same sample that the other prediction equations were compared with. Results Significant relationships were evident between 6MWT actual and 6MWT predicted using all of the commonly available prediction equations (all P<0.05 or better) with the exception of the Alameri et al prediction equation (P>0.05). A series of paired t-tests indicated significant differences between 6MWT actual and 6MWT predicted for all available prediction equations (all P<0.05 or better) with the exception of the Iwama et al equation (P = .540). The Iwama et al equation also had similar bias (79.8m) and a coefficient of variation of over 15%. Using sample 2, a log-linear model significantly predicted 6MWT from the log of body mass and height and age (P = 0.001, adjusted R2 = .526), predicting 52.6% of the variance in actual 6MWT. When this allometric equation was applied to the original sample, the relationship between 6MWT actual and 6MWT predicted was in excess of values reported for the other previously validated prediction equations (r = .706, P = 0.001). There was a significant difference between actual 6MWT and 6MWT predicted using this new equation (P = 0.001) but the bias, standard deviation of differences and coefficient of variation were all less than for the other equations. Conclusions Where actual assessment of the 6MWT is not possible, the allometrically derived equation presented in the current

  15. Performance in the 6-minute walk test and postoperative pulmonary complications in pulmonary surgery: an observational study

    PubMed Central

    Santos, Bruna F. A.; Souza, Hugo C. D.; Miranda, Aline P. B.; Cipriano, Federico G.; Gastaldi, Ada C.

    2016-01-01

    OBJECTIVES: To assess functional capacity in the preoperative phase of pulmonary surgery by comparing predicted and obtained values for the six-minute walk test (6MWT) in patients with and without postoperative pulmonary complication (PPC) METHOD: Twenty-one patients in the preoperative phase of open thoracotomy were evaluated using the 6MWT, followed by monitoring of the postoperative evolution of each participant who underwent the routine treatment. Participants were then divided into two groups: the group with PPC and the group without PPC. The results were also compared with the predicted values using reference equations for the 6MWT RESULTS: Over half (57.14%) of patients developed PPC. The 6MWT was associated with the odds for PPC (odds ratio=22, p=0.01); the group without PPC in the postoperative period walked 422.38 (SD=72.18) meters during the 6MWT, while the group with PPC walked an average of 340.89 (SD=100.93) meters (p=0.02). The distance traveled by the group without PPC was 80% of the predicted value, whereas the group with PPC averaged less than 70% (p=0.03), with more appropriate predicted values for the reference equations CONCLUSIONS: The 6MWT is an easy, safe, and feasible test for routine preoperative evaluation in pulmonary surgery and may indicate patients with a higher chance of developing PPC. PMID:26786074

  16. [Interpretation and use of routine pulmonary function tests: Spirometry, static lung volumes, lung diffusion, arterial blood gas, methacholine challenge test and 6-minute walk test].

    PubMed

    Bokov, P; Delclaux, C

    2016-02-01

    Resting pulmonary function tests (PFT) include the assessment of ventilatory capacity: spirometry (forced expiratory flows and mobilisable volumes) and static volume assessment, notably using body plethysmography. Spirometry allows the potential definition of obstructive defect, while static volume assessment allows the potential definition of restrictive defect (decrease in total lung capacity) and thoracic hyperinflation (increase in static volumes). It must be kept in mind that this evaluation is incomplete and that an assessment of ventilatory demand is often warranted, especially when facing dyspnoea: evaluation of arterial blood gas (searching for respiratory insufficiency) and measurement of the transfer coefficient of the lung, allowing with the measurement of alveolar volume to calculate the diffusing capacity of the lung for CO (DLCO: assessment of alveolar-capillary wall and capillary blood volume). All these pulmonary function tests have been the subject of an Americano-European Task force (standardisation of lung function testing) published in 2005, and translated in French in 2007. Interpretative strategies for lung function tests have been recommended, which define abnormal lung function tests using the 5th and 95th percentiles of predicted values (lower and upper limits of normal values). Thus, these recommendations need to be implemented in all pulmonary function test units. A methacholine challenge test will only be performed in the presence of an intermediate pre-test probability for asthma (diagnostic uncertainty), which is an infrequent setting. The most convenient exertional test is the 6-minute walk test that allows the assessment of walking performance, the search for arterial desaturation and the quantification of dyspnoea complaint.

  17. Effect of the 6-minute walk test on plantar loading and capability to produce ankle plantar flexion forces.

    PubMed

    Vie, Bruno; Griffon, Patricia; Bijoux, Audrey; Cadiere, Julie; Weber, Jean Paul; Jammes, Yves

    2016-09-01

    The six-minute walk test (6MWT) is used to evaluate the ambulatory capacity of patients suffering from respiratory disorders, obesity or neuromuscular diseases. Our primary aim was to evaluate the effects of the 6MWT on the postural sway and the ankle plantar flexion forces in healthy subjects. We measured the ankle plantar flexion forces and the plantar contact area before and after a 6MWT in normal weight and overweight subjects with no history of respiratory, cardiac, and neuromuscular disorders. A post-6MWT sensation of bodily fatigue was evaluated by Multidimensional Fatigue Inventory (MFI) and Pichot fatigue scales. A computerized pedobarographic platform was used to collect the mean plantar contact area, the changes of the center of pressure (CoP) surface and its medial and lateral deviations. In a limited number of subjects, the reproducibility of all the measurements was explored. In both groups, the 6MWT elicited a sensation of bodily fatigue. It also significantly reduced the ankle plantar flexion forces, and increased both the mean plantar contact area and the CoP surface, the changes being not apparent after 10min. The post-6MWT lateral CoP deviations were accentuated in normal weight subjects, while an increase in medial CoP deviations occurred in overweight ones. The 6MWT-induced changes in the plantar flexion force and pedobarographic variables were reproducible. Because this study clearly showed some post-6MWT alterations of the subjects' posture sway of our subjects, we questioned the possible mechanisms occurring that could explain the altered muscle force and the transient destabilization of posture after the 6MWT.

  18. THE 6-MINUTE WALK TEST AND OTHER CLINICAL ENDPOINTS IN DUCHENNE MUSCULAR DYSTROPHY: RELIABILITY, CONCURRENT VALIDITY, AND MINIMAL CLINICALLY IMPORTANT DIFFERENCES FROM A MULTICENTER STUDY

    PubMed Central

    McDonald, Craig M; Henricson, Erik K; Abresch, R Ted; Florence, Julaine; Eagle, Michelle; Gappmaier, Eduard; Glanzman, Allan M; Spiegel, Robert; Barth, Jay; Elfring, Gary; Reha, Allen; Peltz, Stuart W

    2013-01-01

    Introduction: An international clinical trial enrolled 174 ambulatory males ≥5 years old with nonsense mutation Duchenne muscular dystrophy (nmDMD). Pretreatment data provide insight into reliability, concurrent validity, and minimal clinically important differences (MCIDs) of the 6-minute walk test (6MWT) and other endpoints. Methods: Screening and baseline evaluations included the 6-minute walk distance (6MWD), timed function tests (TFTs), quantitative strength by myometry, the PedsQL, heart rate–determined energy expenditure index, and other exploratory endpoints. Results: The 6MWT proved feasible and reliable in a multicenter context. Concurrent validity with other endpoints was excellent. The MCID for 6MWD was 28.5 and 31.7 meters based on 2 statistical distribution methods. Conclusions: The ratio of MCID to baseline mean is lower for 6MWD than for other endpoints. The 6MWD is an optimal primary endpoint for Duchenne muscular dystrophy (DMD) clinical trials that are focused therapeutically on preservation of ambulation and slowing of disease progression. Muscle Nerve 48: 357–368, 2013 PMID:23674289

  19. THE 6-MINUTE WALK TEST AND OTHER ENDPOINTS IN DUCHENNE MUSCULAR DYSTROPHY: LONGITUDINAL NATURAL HISTORY OBSERVATIONS OVER 48 WEEKS FROM A MULTICENTER STUDY

    PubMed Central

    Mcdonald, Craig M; Henricson, Erik K; Abresch, R Ted; Florence, Julaine M; Eagle, Michelle; Gappmaier, Eduard; Glanzman, Allan M; Spiegel, Robert; Barth, Jay; Elfring, Gary; Reha, Allen; Peltz, Stuart

    2013-01-01

    Introduction: Duchenne muscular dystrophy (DMD) subjects ≥5 years with nonsense mutations were followed for 48 weeks in a multicenter, randomized, double-blind, placebo-controlled trial of ataluren. Placebo arm data (N = 57) provided insight into the natural history of the 6-minute walk test (6MWT) and other endpoints. Methods: Evaluations performed every 6 weeks included the 6-minute walk distance (6MWD), timed function tests (TFTs), and quantitative strength using hand-held myometry. Results: Baseline age (≥7 years), 6MWD, and selected TFT performance are strong predictors of decline in ambulation (Δ6MWD) and time to 10% worsening in 6MWD. A baseline 6MWD of <350 meters was associated with greater functional decline, and loss of ambulation was only seen in those with baseline 6MWD <325 meters. Only 1 of 42 (2.3%) subjects able to stand from supine lost ambulation. Conclusion: Findings confirm the clinical meaningfulness of the 6MWD as the most accepted primary clinical endpoint in ambulatory DMD trials. PMID:23681930

  20. Prognostic indices among hypertensive heart failure patients in Nigeria: the roles of 24-hour Holter electrocardiography and 6-minute walk test

    PubMed Central

    Mene-Afejuku, Tuoyo O; Balogun, Michael O; Akintomide, Anthony O; Adebayo, Rasaaq A

    2017-01-01

    Background Hypertensive heart failure (HHF) is associated with a poor prognosis. There is paucity of data in Nigeria on prognosis among HHF patients elucidating the role of 24-hour Holter electrocardiogram (ECG) in concert with other risk factors. Objective The aim of this study was to determine the prognostic utility of 24-hour Holter ECG, the 6-minute walk test (6-MWT), echocardiography, clinical and laboratory parameters among HHF patients. Methods A total of 113 HHF patients were recruited and followed up for 6 months. Thirteen of these patients were lost to follow-up, and as a result only 100 HHF patients were analyzed. All the patients underwent baseline laboratory tests, echocardiography, 24-hour Holter ECG and the 6-MWT. HHF patients were analyzed as “mortality vs alive” and as “events vs no-events” based on the outcome at the end of 6 months. Events was defined as HHF patients who were rehospitalized for heart failure (HF), had prolonged hospital stay or died. No-events group was defined as HHF patients who did not meet the criteria for the events group. Results HHF patients in the mortality group (n = 7) had significantly higher serum urea (5.71 ± 2.07 mmol/L vs 3.93 ± 1.45 mmol/L, p = 0.003) than that in those alive. After logistic regression, high serum urea conferred increased mortality risk (p = 0.035). Significant premature ventricular complexes (PVCs) on 24-hour Holter ECG following logistic regression were also significantly higher (p = 0.015) in the mortality group than in the “alive” group (n = 93) at the end of the 6-month follow-up period. The 6-minute walk distance (6-MWD) was least among the HHF patients who died (167.26 m ± 85.24 m). However, following logistic regression, the 6-MWT was not significant (p = 0.777) for predicting adverse outcomes among HHF patients. Patients in the events group (n = 41) had significantly higher New York Heart Association (NYHA) class (p = 0.001), Holter-detected ventricular tachycardia (VT; p

  1. Effects of Exercise Training versus Attention on Plasma B-type Natriuretic Peptide, 6-Minute Walk Test and Quality of Life in Individuals with Heart Failure

    PubMed Central

    Norman, Joseph F.; Pozehl, Bunny J.; Duncan, Kathleen A.; Hertzog, Melody A.; Krueger, Steven K.

    2012-01-01

    Purpose The purpose of this study was to compare an Exercise Training Group (EX) with an Attention-Control Group (AT-C) to more specifically assess the impact of exercise training on individuals with heart failure (HF). Methods Forty-two individuals with HF were randomized to AT-C or EX that met with the same frequency and format of investigator interaction. Baseline, 12- and 24-week measurements of B-type naturetic peptide (BNP), 6-minute walk test (6-MWT), and the Kansas City Cardiomyopathy Questionnaire (KCCQ) were obtained. Results BNP tended to increase in the AT-C while remaining stable in the EX over time. A clinically significant increase in 6-MWT was demonstrated by the EX but not the AT-C. The EX achieved a clinically significant change on the KCCQ at 12 weeks, with further improvement by 24 weeks, while the AT-C demonstrated a clinically significant change at 24 weeks. Conclusions Attention alone was inadequate to positively impact BNP levels or 6-MWT distances, but did have a positive impact on quality of life after 24 weeks. Although exercise offers enhanced benefits, individuals with HF unable to participate in an exercise program may still gain quality of life benefits from participation in a peer-support group that discusses topics pertinent to HF. PMID:23304096

  2. Between-rater reliability of the 6-minute walk test, berg balance scale, and handheld dynamometry in people with multiple sclerosis.

    PubMed

    Toomey, Elaine; Coote, Susan

    2013-01-01

    This study investigated the between-rater reliability of the Berg Balance Scale (BBS), 6-Minute Walk test (6MW), and handheld dynamometry (HHD) in people with multiple sclerosis (MS). Previous studies that examined BBS and 6MW reliability in people with MS have not used more than two raters, or analyzed different mobility levels separately. The reliability of HHD has not been previously reported for people with MS. In this study, five physical therapists assessed eight people with MS using the BBS, 6MW, and HHD, resulting in 12 pairs of data. Data were analyzed using intraclass correlation coefficients (ICCs), Spearman correlation coefficients (SCCs), and Bland and Altman methods. The results suggest excellent agreement for the BBS (SCC = 0.95, mean difference between raters [d̄] = 2.08, standard error of measurement [SEM] = 1.77) and 6MW (ICC = 0.98, d̄ = 5.22 m, SEM = 24.76 m) when all mobility levels are analyzed together. Reliability is lower in less mobile people with MS (BBS SCC = 0.6, d̄ = -1.83; 6MW ICC = 0.95, d̄ = 20.04 m). Although the ICC and SCC results for HHD suggest good-to-excellent reliability (0.65-0.85), d̄ ranges up to 17.83 N, with SEM values as high as 40.95 N. While the small sample size is a limitation of this study, the preliminary evidence suggests strong agreement between raters for the BBS and 6MW and decreased agreement between raters for people with greater mobility problems. The mean differences between raters for HHD are probably too high for it to be applied in clinical practice.

  3. The 6-minute walk: a new measure of exercise capacity in patients with chronic heart failure

    PubMed Central

    Guyatt, Gordon H.; Sullivan, Michael J.; Thompson, Penelope J.; Fallen, Ernest L.; Pugsley, Stewart O.; Taylor, D. Wayne; Berman, Leslie B.

    1985-01-01

    Cycle and treadmill exercise tests are unsuitable for elderly, frail and severely limited patients with heart failure and may not reflect capacity to undertake day-to-day activities. Walking tests have proved useful as measures of outcome for patients with chronic lung disease. To investigate the potential value of the 6-minute walk as an objective measure of exercise capacity in patients with chronic heart failure, the test was administered six times over 12 weeks to 18 patients with chronic heart failure and 25 with chronic lung disease. The subjects also underwent cycle ergometer testing, and their functional status was evaluated by means of conventional measures. The walking test proved highly acceptable to the patients, and stable, reproducible results were achieved after the first two walks. The results correlated with the conventional measures of functional status and exercise capacity. The authors conclude that the 6-minute walk is a useful measure of functional exercise capacity and a suitable measure of outcome for clinical trials in patients with chronic heart failure. PMID:3978515

  4. 013. Complementary role of 6-minutes walking test (6MWT) in the assessment of functional status of patients with chronic obstructive pulmonary disease (COPD)

    PubMed Central

    Mathioudakis, Alexander G.; Evangelopoulou, Efstathia I.; Karapiperis, Georgios C.; Perros, Elias I.; Simou, Georgia; Kiritsi, Evridiki; Chatzimavridou-Grigoriadou, Victoria; Mathioudakis, Georgios A.

    2015-01-01

    Background Despite its limited repeatability, spirometry is the most widely used method of assessment of the pulmonary ventilation. However, it is not a safe measure of the functional reserve of chronic obstructive pulmonary disease (COPD) patients with multiple comorbidities. Consequently, a stress test that would include cardiovascular and neuromuscular variables would be a useful complimentary test. Objective The aim of this observational study was to investigate the correlation between FEV1 and 6MWT, in patients with stable COPD (mean FEV1% pred =43.9%, SD =15.3). Methods 174 male ex-smokers with stable COPD, with a mean age of 63±6.7 years, mean height of 171.4 and weight of 73.9 were included and grouped according to their GOLD severity staging. A control group consisting of 87 healthy volunteers (mean age: 64±6.2, height: 175.2 and weight: 70.5) was also included. All the patient and controls had spirometry before and after bronchodilatation, on a daily scaled turbine spirometer, and 6MWT, on a 10-meter straight corridor. Elapsed distance (eD), haemoglobin saturation (Sats) and heart rate (HR) were continuously monitored during the 6MWT. All the data of our study were imported in an excel sheet for statistical analysis. Results Among the main results of our study, FEV1 decrease by year of age was less pronounced among healthy volunteers (21 mL/year, r2=0.4) compared to COPD patients (53 mL/year, r2=0.06). Similarly, volunteers had a significantly lower decrease by year of age in eD (2.3 m/year, r2=0.4) compared to COPD patients (7.7 m/year, r2=0.7). A more pronounced decrease of eD by year of age was recognized in patients with later COPD stages, while weight was more significantly correlated to eD compared to age. Post-bronchodilatation FEV1 was correlated to eD in COPD patients (r2=0.7); for each 1% decrease in the FEV1, COPD patients also lose approximately 7 m of walking distance in 6MWT. Conclusions 6MWT is a reliable measure of COPD progression and

  5. The 6-Minute Walk Test and Person-Reported Outcomes in Boys with Duchenne Muscular Dystrophy and Typically Developing Controls: Longitudinal Comparisons and Clinically-Meaningful Changes Over One Year

    PubMed Central

    Henricson, Erik; Abresch, Richard; Han, Jay J.; Nicorici, Alina; Goude Keller, Erica; de Bie, Evan; McDonald, Craig M.

    2013-01-01

    Introduction: Data is currently lacking anchoring a 30-meter longitudinal change in walking ability by 6-minute walk test (6MWT) in Duchenne muscular dystrophy as a minimal clinically important difference and “clinically meaningful” person-reported outcomes (PROs) at differing levels of ambulatory ability. Methods: We describe correlation between measures, 1-year change in measures, and correlation of 1-year changes between measures for the six-minute walk test (6MWT), 10-meter run/walk velocity, PedsQL and POSNA Pediatric Outcomes Data Collection Instrument (PODCI) in 24 4-12 year old. ambulatory DMD and 36 typical controls, and determine if minimal clinically important differences (MCID) of PROs contribute to different estimates of 6-minute walk distance (6MWD) change at differing levels of ability. Results: PedsQL total and physical function and PODCI global, transfer/mobility and sports/physical function PROs demonstrated significant differences between DMD and controls (p<0.00001). In DMD, 6MWD and 10-meter run/walk velocity were correlated with PODCI domain scores, with the transfer/mobility scale showing the strongest relationship (r=0.79 and r=0.76). In DMD, 6MWD distance and 10-meter run/walk velocity weakly correlated with PedsQL domain scores. In DMD, 6MWD, 10-meter run/walk velocity, and PODCI global and transfer and basic mobility demonstrated significant one-year change and exceeded the amount of change representing MCID. In DMD, 6MWD change highly correlated with change in PODCI global and PODCI transfer/mobility scores (r=0.76 and r=0.93). PODCI global and PODCI transfer/mobility scales provided the best estimates of 6MWT performance. A “meaningful” 4.5 point change in a low PODCI transfer / basic mobility score of 30 to 34.5 was associated with a 5.6m 6MWD change from 150.3 to 155.9m. At PODCI levels closer to normative levels for healthy controls, the change in 6MWD distance associated with a “meaningful” change in PODCI scores was

  6. Percent-predicted 6-minute walk distance in duchenne muscular dystrophy to account for maturational influences.

    PubMed

    Henricson, Erik; Abresch, Richard; Han, Jay J; Nicorici, Alina; Goude Keller, Erica; Elfring, Gary; Reha, Allen; Barth, Jay; McDonald, Craig M

    2012-01-25

    We recently described a modified version of the 6-minute walk test (6MWT) for Duchenne muscular dystrophy (DMD) based partly on the American Thoracic Society (ATS) guidelines. This measure has shown reliability, validity and utility as a primary outcome measure in DMD clinical trials. Because loss of muscle function in DMD occurs against the background of normal childhood growth and development, younger children with DMD can show increase in distance walked during 6MWT over ~1 year despite progressive muscular impairment. In this study, we compare 6-minute walk distance (6MWD) data from DMD boys (n=17) and typically developing control subjects (n=22) to existing normative data from age- and sex-matched children and adolescents. An age- and height-based equation fitted to normative data by Geiger and colleagues was used to convert 6MWD to a percent-predicted (%-predicted) value in boys with DMD. Analysis of %-predicted 6MWD data represents a method to account for normal growth and development, and shows that gains in function at early ages represents stable rather than improving abilities in boys with DMD. Boys with DMD from 4-7 years of age maintain a stable 6MWD approximately 80% of that of typically developing peers, with the deficit progressing at a variable rate thereafter.

  7. Percent-Predicted 6-Minute Walk Distance in Duchenne Muscular Dystrophy to Account for Maturational Influences

    PubMed Central

    Henricson, Erik; Abresch, Richard; Han, Jay J.; Nicorici, Alina; Goude Keller, Erica; Elfring, Gary; Reha, Allen; Barth, Jay; McDonald, Craig M.

    2012-01-01

    We recently described a modified version of the 6-minute walk test (6MWT) for Duchenne muscular dystrophy (DMD) based partly on the American Thoracic Society (ATS) guidelines. This measure has shown reliability, validity and utility as a primary outcome measure in DMD clinical trials. Because loss of muscle function in DMD occurs against the background of normal childhood growth and development, younger children with DMD can show increase in distance walked during 6MWT over ~1 year despite progressive muscular impairment. In this study, we compare 6-minute walk distance (6MWD) data from DMD boys (n=17) and typically developing control subjects (n=22) to existing normative data from age- and sex-matched children and adolescents. An age- and height-based equation fitted to normative data by Geiger and colleagues was used to convert 6MWD to a percent-predicted (%-predicted) value in boys with DMD. Analysis of %-predicted 6MWD data represents a method to account for normal growth and development, and shows that gains in function at early ages represents stable rather than improving abilities in boys with DMD. Boys with DMD from 4-7 years of age maintain a stable 6MWD approximately 80% of that of typically developing peers, with the deficit progressing at a variable rate thereafter. PMID:22306689

  8. Determinants of 6-minute walk distance in patients with idiopathic pulmonary fibrosis undergoing lung transplant evaluation

    PubMed Central

    Rivera-Lebron, Belinda N.; Kreider, Maryl; Lee, James; Kawut, Steven M.

    2016-01-01

    Abstract Little is known about the physiologic determinants of 6-minute walk distance in idiopathic pulmonary fibrosis. We investigated the demographic, pulmonary function, echocardiographic, and hemodynamic determinants of 6-minute walk distance in patients with idiopathic pulmonary fibrosis evaluated for lung transplantation. We performed a cross-sectional analysis of 130 patients with idiopathic pulmonary fibrosis who completed a lung transplantation evaluation at the Hospital of the University of Pennsylvania between 2005 and 2010. Multivariable linear regression analysis was used to generate an explanatory model for 6-minute walk distance. After adjustment for age, sex, race, height, and weight, the presence of right ventricular dilation was associated with a decrease of 50.9 m (95% confidence interval [CI], 8.4–93.3) in 6-minute walk distance (P=0.02). For each 200-mL reduction in forced vital capacity, the walk distance decreased by 15.0 m (95% CI, 9.0–21.1; P<0.001). For every increase of 1 Wood unit in pulmonary vascular resistance, the walk distance decreased by 17.3 m (95% CI, 5.1–29.5; P=0.006). Six-minute walk distance in idiopathic pulmonary fibrosis depends in part on circulatory impairment and the degree of restrictive lung disease. Future trials that target right ventricular morphology, pulmonary vascular resistance, and forced vital capacity may potentially improve exercise capacity in patients with idiopathic pulmonary fibrosis. PMID:27076905

  9. Individualized Prediction of Changes in 6-Minute Walk Distance for Patients with Duchenne Muscular Dystrophy

    PubMed Central

    Goemans, Nathalie; vanden Hauwe, Marleen; Signorovitch, James; Swallow, Elyse; Song, Jinlin

    2016-01-01

    Background Deficits in ambulatory function progress at heterogeneous rates among individuals with Duchenne muscular dystrophy (DMD). The resulting inherent variability in ambulatory outcomes has complicated the design of drug efficacy trials and clouded the interpretation of trial results. We developed a prediction model for 1-year change in the six minute walk distance (6MWD) among DMD patients, and compared its predictive value to that of commonly used prognostic factors (age, baseline 6MWD, and steroid use). Methods Natural history data were collected from DMD patients at routine follow up visits approximately every 6 months over the course of 2–5 years. Assessments included ambulatory function and steroid use. The annualized change in 6MWD (Δ6MWD) was studied between all pairs of visits separated by 8–16 months. Prediction models were developed using multivariable regression for repeated measures, and evaluated using cross-validation. Results Among n = 191 follow-up intervals (n = 39 boys), mean starting age was 9.4 years, mean starting 6MWD was 351.8 meters, and 75% had received steroids for at least one year. Over the subsequent 8–16 months, mean Δ6MWD was -37.0 meters with a standard deviation (SD) of 93.7 meters. Predictions based on a composite of age, baseline 6MWD, and steroid use explained 28% of variation in Δ6MWD (R2 = 0.28, residual SD = 79.4 meters). A broadened prognostic model, adding timed 10-meter walk/run, 4-stair climb, and rise from supine, as well as height and weight, significantly improved prediction, explaining 59% of variation in Δ6MWD after cross-validation (R2 = 0.59, residual SD = 59.7 meters). Conclusions A prognostic model incorporating timed function tests significantly improved prediction of 1-year changes in 6MWD. Explained variation was more than doubled compared to predictions based only on age, baseline 6MWD, and steroid use. There is significant potential for composite prognostic models to inform DMD clinical trials

  10. [Use of the six-minute walk test in cardiology].

    PubMed

    Kervio, G; Ville, N S; Leclercq, C; Daubert, J C; Carré, F

    2005-12-01

    The symptom-limited exercise test is nowadays the gold standard to assess the exercise tolerance and the effects of different treatments in patients with chronic heart failure (CHF). A simpler alternative to this test is the 6-minute walk test. The 6-minute walk test is easy to realize and well-tolerated. Moreover, it is reliable just after one familiarization practice and requires standardization. Indeed, its conduction, which is submitted to some security precautions, can be altered by variation factors. The distance walked during the 6 minutes was the only parameter studied during the test. This parameter could allow judging the CHF severity and prognostic. The analyse of cardiorespiratory parameters has shown that the 6-minute walk test relative intensity is near to the peak individual values. Moreover, the cardiac and ventilatory adaptation of patient during this test depends to his own functional capacity. Lastly, the 6-minute walk test is a submaximal constant-load exercise, which should be performed in complement to the symptom-limited exercise test in cardiac patients.

  11. Reliability and validity of the 6-minute arm test for the evaluation of cardiovascular fitness in individuals with spinal cord injury

    PubMed Central

    Hol, Adrienne T; Eng, Janice J; Miller, William C; Sproule, Shannon; Krassioukov, Andrei V

    2011-01-01

    Objectives (1) To design a submaximal arm ergometry test (6-minute arm test [6-MAT]), for individuals with spinal cord injury (SCI) and (2) to determine the test-retest reliability and concurrent validity of this test. Design Prospective, exploratory, methodological study. To determine test-retest reliability, subjects completed the 6-MAT on 2 days, separated by 1 week. Validity was determined by comparing 6-MAT results with VO2peak. Setting Tertiary rehabilitation center. Participants 30 subjects with SCI (mean age=36.3 years; 83% male). Intervention Not applicable. Main Outcome Measures Subjects were evaluated on the 6-MAT and a VO2peak test. Results All subjects were able to complete the 6-MAT. Test-retest reliability of steady state VO2 and heart rate (HR) during the 6-MAT were excellent; intraclass correlation coefficient (ICC)=0.81 [95% confidence interval (CI)=0.58–0.92], and 0.90 (95%CI=0.75–0.96), respectively. The correlation between VO2peak and 6-MAT VO2 was excellent (r=0.92), while those between VO2peak and 6-MAT HR (r=0.63) and VO2peak and 6-MAT power output (PO) (r=0.73) were good. Conclusions This study demonstrated that the 6-MAT has acceptable values for test-retest reliability and validity. The 6-MAT should be further tested for responsiveness to enhance its use as a clinical tool. PMID:17398251

  12. Ecological Validity of Walking Capacity Tests in Multiple Sclerosis

    PubMed Central

    Stellmann, J. P.; Neuhaus, A.; Götze, N.; Briken, S.; Lederer, C.; Schimpl, M.; Heesen, C.; Daumer, M.

    2015-01-01

    Background Ecological validity implicates in how far clinical assessments refer to real life. Short clinical gait tests up to ten meters and 2- or 6-Minutes Walking Tests (2MWT/6MWT) are used as performance-based outcomes in Multiple Sclerosis (MS) studies and considered as moderately associated with real life mobility. Objective To investigate the ecological validity of 10 Meter Walking Test (10mWT), 2MWT and 6MWT. Methods Persons with MS performed 10mWT, 6MWT including 2MWT and 7 recorded days by accelerometry. Ecological validity was assumed if walking tests represented a typical walking sequence in real-life and correlations with accelerometry parameters were strong. Results In this cohort (n=28, medians: age=45, EDSS=3.2, disease duration=9 years), uninterrupted walking of 2 or 6 minutes occurred not frequent in real life (2.61 and 0.35 sequences/day). 10mWT correlated only with slow walking speed quantiles in real life. 2MWT and 6MWT correlated moderately with most real life walking parameters. Conclusion Clinical gait tests over a few meters have a poor ecological validity while validity is moderate for 2MWT and 6MWT. Mobile accelerometry offers the opportunity to control and improve the ecological validity of MS mobility outcomes. PMID:25879750

  13. Impact of adherence to GOLD guidelines on 6-minute walk distance, MRC dyspnea scale score, lung function decline, quality of life, and quality-adjusted life years in a Shanghai suburb.

    PubMed

    Jiang, Y Q; Zhu, Y X; Chen, X L; Xu, X; Li, F; Fu, H J; Shen, C Y; Lu, Y Y; Zhuang, Q J; Xu, G; Cai, Y Y; Zhang, Y; Liu, S S; Zhu, M Y; Li, S H

    2015-08-03

    We performed a 1-year cluster-randomized field trial to assess the effect of standardized management of chronic obstructive pulmonary disease (COPD) on lung function and quality of life (QOL) measures in patients in China. We used the Global Initiative for Chronic Obstructive Lung Disease (GOLD) treatment guidelines and assessed indexes including pulmonary function, QOL, quality-adjusted life years (QALY), Medical Research Council (MRC) dyspnea scale, 6-min walk distance (6-MWD), number of emergency visits, and frequency of hospitalization. Of a total of 711 patients with chronic cough and asthma, 132 were diagnosed as having COPD and 102 participated in this study [intervention group (N = 47); control group (N = 55)]. We found that adherence to GOLD guidelines had a perceivable impact on 6-MWD, MRC dyspnea scale score, and QOL. The average QALY increased by 1.42/person/year in the intervention group, but declined by 0.95/person/year in the control group. We conclude that standardized management improves disease severity, QOL, and QALY in COPD patients when treatment protocols adhere to GOLD guidelines.

  14. The six-minute walk--an adequate exercise test for pacemaker patients?

    PubMed

    Langenfeld, H; Schneider, B; Grimm, W; Beer, M; Knoche, M; Riegger, G; Kochsiek, K

    1990-12-01

    In many pacemaker patients bicycle and treadmill ergometry are not practicable. As an alternative, we performed a 6-minute walk on a 20-m corridor in 97 pacemaker patients, who were asked to walk as far as possible determining their speed by themselves. Results were compared with those of bicycle ergometry in 42 of these patients and with treadmill exercise of a group of 92 other pacemaker patients. In the 6-minute walk, performance and maximal heart rate were slightly lower (49 +/- 18 W; 96 +/- 23 beats/min) than in bicycle (57 +/- 16 W; 110 +/- 26 beats/min) and treadmill ergometry (50 +/- 37 W; 102 +/- 35 beats/min). A good correlation was found between walking and bicycling (r = 0.74) and in subgroups of patients with different pacemaker indications. All patients preferred the walk to bicycle ergometry considering it to be more related to daily physical activity. In conclusion, a 6-minute walk is a simple and physiological exercise test for nearly all pacemaker patients with good correlation to other types of exercise. It seems to be preferable to other tests because of its better acceptance and practicability.

  15. Foot Progression Angle Walking Test

    PubMed Central

    Ranawat, Anil S.; Gaudiani, Michael A.; Slullitel, Pablo A.; Satalich, James; Rebolledo, Brian J.

    2017-01-01

    Background: Determining an accurate clinical diagnosis for nonarthritic hip pain may be challenging, as symptoms related to femoroacetabular impingement (FAI) or hip instability can be difficult to elucidate with current testing methods. In addition, commonly utilized physical examination maneuvers are static and do not include a dynamic or weightbearing assessment to reproduce activity-related symptoms. Therefore, implementing a dynamic assessment for FAI and hip instability could help to improve diagnostic accuracy for routine clinical examinations of patients with nonarthritic hip pain. Purpose: To assess the efficacy of a novel diagnostic foot progression angle walking (FPAW) test for identifying hip pathology related to FAI or hip instability. Study Design: Prospective cohort study; Level of evidence, 3. Methods: This prospective study included 199 consecutive patients who were evaluated for unilateral hip pain and who underwent FPAW testing along with standard physical examination testing. Demographic data, including age, sex and hip laterality, were collected from each patient. FPAW testing was performed with directed internal and external foot progression angles from their baseline measurements, with a positive test reproducing pain and/or discomfort. Comparisons were then made with flexion adduction internal rotation (FADIR) and flexion abduction external rotation (FABER) tests as the designated diagnostic standard examinations for FAI and hip instability, respectively. Sensitivity and specificity, along with the McNemar chi-square test for group comparison, were used to generate summary statistics. In addition, areas under the combined receiver operating characteristic curves (AUC) of test performance were calculated for both FPAW and the designated standard examination tests (FADIR, FABER). Radiographic imaging was used subsequently to confirm the diagnosis. Results: The average age of the study cohort was 35.4 ± 11.8 years, with 114 patients being

  16. Submaximal Exercise Testing Treadmill and Floor Walking.

    DTIC Science & Technology

    1978-05-01

    Association, 65(Suppl 1): 18-25, 1969. 35. Traugh, G. H., Corcoran, P. J., and Reyes , R. L., "Energy Expenditure of Ambulation in Patients with Above Knee...subjects were measured over three walking velocities. 1 No comments were offered on the subjects attire during the testa or the experimental conditions...Testing," Journal of the South Carolina Medical Association, 65(Suppl 1): 18- ,- _19-69.7 .. i 35. Traugh, G. H., Corcoran, P. J., and Reyes , R. L

  17. Cardiac Effect of Interstitial Lung Disease Correlated with Spirometry and Six Minute Walk Test

    PubMed Central

    Agrawal, Mitali Bharat

    2017-01-01

    Introduction The cardiac effect of different pulmonary functions, six minute walk distance, arterial blood gases and saturation in Interstitial Lung Disease (ILD) is not much known. So this study, a tertiary care hospital experience that entails to know the various factors in Pulmonary Hypertension (PH) mentioned above causing PH and their correlation with PH. Aim To study the correlation of PH in patients with ILD with spirometry and six minute walk test (6MWT). Materials and Methods All consecutive patients with confirmed diagnosis of ILD taken over a period of 1½year in tertiary care hospital. 6MWT and spirometry were performed as per the American Thoracic Guidelines. Percent predicted 6 minute walk distance was calculated using Enright et al., and Indian reference equation. PH was diagnosed using 2-D echo. The spirometry variables and 6MWT were then correlated with the mean pulmonary artery pressure. Results There were 75 patients. About 66.66 % had PH on 2-D echo. The mean% predicted six minute walk distance as per the Indian reference equation, pre- and post- exercise PaO2 as well as desaturation had a significant correlation with PH. Spirometry variables Forced Expiratory Volume in First Second (FEV1) and Forced Vital Capacity (FVC) did not correlate with PH. Conclusion Thus, the 6MWT correlated significantly with PH while spirometry did not. PMID:28384908

  18. Comparing Two Conditions of Administering the Six-Minute Walk Test in People with Multiple Sclerosis

    PubMed Central

    Sandroff, Brian M.; Pilutti, Lara A.; Dlugonski, Deirdre; Learmonth, Yvonne C.; Pula, John H.

    2014-01-01

    Objective: This quasi-experimental study was conducted to determine whether differences existed in the total distance walked and energy expended between two conditions of administering the 6-Minute Walk test (6MW) across different levels of disability in people with multiple sclerosis (MS). Methods: The sample comprised 160 individuals with MS. One group of participants (n = 82) completed a 6MW while wearing a portable metabolic unit (K4b2, Cosmed, Italy) in a square hallway with four corridors and performing 90° turns. Another group (n = 78) completed a 6MW while wearing the same metabolic unit in a single corridor and performing 180° turns. Main outcome measures included total distance walked (in feet) and oxygen consumption (in milliliters per minute) expressed as 30-second averages for 1 minute before the 6MW and over the entire 6MW. Disability status was assessed using the Patient-Determined Disease Steps scale. Results: Participants undertaking the 6MW in a single corridor (1412 ft) walked 37 ft (2.7%) farther than those undertaking the test in a square hallway (1375 ft), but this difference was not statistically significant (F = 0.45, P = .51). Those completing the 6MW in a single corridor expended more energy than those completing the 6MW in the square hallway with four corridors (F = 3.41, P < .01). Conclusions: Either protocol is acceptable, but researchers should be aware of the additional physiological demands when administering the 6MW in a single corridor with 180° turns. PMID:24688354

  19. A comparison of at-home walking and 10-meter walking test parameters of individuals with post-stroke hemiparesis.

    PubMed

    Nagano, Katsuhito; Hori, Hideaki; Muramatsu, Ken

    2015-02-01

    [Purpose] The purpose of this study was to clarify the difference in gait parameters of at-home walking and the 10-meter walking test results of individuals with hemiparesis. [Subjects] A total of 14 hemiparetic stroke recovery patients participated in this study. Inclusion criteria were: living at home, the ability to walk independently, and demonstrated low extremity on recovery stages III-V on the Brunnstrom Approach. The average age of the subjects was 66 years. [Methods] We used video surveillance and the inked footprint technique to record usual walking speed and maximum speed patterns both in subjects' homes and during the 10-meter walking test. From these methods, walking speed, stride length, and step rate were calculated. [Results] While both usual and maximum walking speeds of the 10-meter walking test correlated with stride length and step rate, at-home walking speeds only significantly correlated with stride length. [Conclusion] Walking patterns of the 10-meter walking test are quantifiably distinct from those demonstrated in patients' homes, and this difference is mainly characterized by stride length. In order to enhance in-home walking ability, exercises that improve length of stride rather than step rate should be recommended.

  20. The endurance shuttle walk test: an alternative to the six-minute walk test for the assessment of ambulatory oxygen.

    PubMed

    Revill, S M; Noor, M Z; Butcher, G; Ward, M J

    2010-01-01

    UK guidelines for domiciliary oxygen have suggested the six-minute walk test or shuttle walk tests as suitable functional measures for the clinical assessment of ambulatory oxygen (AO). To date, there is limited evidence that would support the use of shuttle walk tests as assessment tools for AO. The endurance shuttle walk test (ESWT) is used increasingly as an assessment tool within pulmonary rehabilitation (PR) but its potential as an investigative test for AO has not been explored. Using the same test for both PR and AO assessment is appealing since it would improve efficiency and act to standardise outcome measures in this patient population. The aim of this study was to examine the responsiveness and repeatability of the ESWT to AO and to compare the response with that of the six-minute walk test (6MWT). Twenty-three patients with chronic obstructive pulmonary disease (COPD) performed, in random order, the ESWT and the 6MWT on air and whilst breathing AO. Oxygen saturation and Borg ratings of breathlessness and perceived exertion were recorded. On a third day, eleven patients repeated the ESWT with AO in order to measure repeatability. There was a significantly greater change in the ESWT with oxygen than the change recorded from the 6MWT (66 [91] vs 6 [28] m respectively; P < .05). When repeated on a separate day, the mean difference (95% CI) between distances walked on the ESWT with AO was 0.91 (-47, 49) m. The ESWT was more responsive than the 6MWT for detecting improvements in walking endurance whilst breathing AO.

  1. Comparison of bioenergetics of walking during a multistage incremental shuttle walk test and a 6-min walk test in active older adults.

    PubMed

    Leone, Mario; Duvergé, Sébastien; Kalinova, Émilia; Bui, Hung Tien; Comtois, Alain S

    2017-04-01

    The goal of the present research was to compare the bioenergetics variability of walking, during the 6-min walk test (6-MWT) and a multistage incremental shuttle walk test (MISWT) in an active older population. Twenty-two healthy physically active older adults with a group mean age of 70.4 ± 5.8 years completed the 6-MWT and the MISWT. Heart rate (HR), walking speed and walking [Formula: see text]O2 were measured throughout each test with a portable metabolic cart. Strong correlations were found for the [Formula: see text]O2 peak and the walking speed (r = 0.91 and r = 0.89 respectively for 6-MWT and MISWT). Differences in [Formula: see text]O2 peak values were analysed with a paired Student's t test. Repeated measures ANOVA were conducted to detect differences between tests. The Bland and Altman plot indicates that the average difference between both tests was 2.5 ml kg(-1) min(-1). MISWT [Formula: see text]O2 peak means were significantly greater than the 6-MWT [Formula: see text]O2 peak mean values (21.6 ± 5.3 vs. 18.9 ± 4.5 ml kg(-1) min(-1)) which indicate bioenergetics differences between the two walking tests. Thus, the MISWT and 6-MWT elicited different walking [Formula: see text]O2 peak and HR suggesting that the MISWT field test challenge the participants to a higher level of cardiovascular and respiratory stress. The walking [Formula: see text]O2 peak recorded for the MISWT was significantly greater than the 6-MWT. Consequently, both tests seem to measure different facets of the aerobic capacity. MISWT seems to be a better indicator of maximal aerobic power whereas the 6-MWT provides more relevant information regarding aerobic endurance in aging population.

  2. [Six-minute walk test in children with neuromuscular disease.

    PubMed

    Cruz-Anleu, Israel Didier; Baños-Mejía, Benjamín Omar; Galicia-Amor, Susana

    2013-01-01

    Background: neuromuscular diseases affect the motor unit. When they evolve, respiratory complications are common; the six-minute walk test plays an important role in the assessment of functional capacity. Methods: prospective, transversal, descriptive and observational study. We studied seven children with a variety of neuromuscular diseases and spontaneous ambulation. We tested their lung function, and administered a six-minute walk test and a test of respiratory muscle strength to these children. Results: the age was 9.8 ± 2.4 years. All patients were males. Forced vital capacity decreased in three patients (42.8 %), forced expiratory volume during the first second (2.04 ± 1.4 L) and peak expiratory flow (4.33 ± 3.3 L/s) were normal. The maximum strength of respiratory muscles was less than 60 % of predicted values. The distance covered in the six-minute walk test was lower when compared with healthy controls (29.9 %). Conclusions: the six-minute walk test can be a useful tool in early stages of this disease, since it is easy to perform and well tolerated by the patients.

  3. Tests of walking balance for screening vestibular disorders.

    PubMed

    Cohen, Helen S; Mulavara, Ajitkumar P; Peters, Brian T; Sangi-Haghpeykar, Haleh; Bloomberg, Jacob J

    2012-01-01

    Few reliable tests are available for screening people rapidly for vestibular disorders although such tests would be useful for a variety of testing situations. Balance testing is widely performed but of unknown value for screening. The goal of this study was to determine the value of tests of walking balance for screening people with vestibular impairments. We tested three groups of patients with known vestibular impairments: benign paroxysmal positional vertigo, unilateral vestibular weakness, and post-acoustic neuroma resection. We compared them to normal subjects. All subjects were independently ambulatory without gait aids. Subjects were tested on tandem walking (TW) with eyes open and eyes closed for 10 steps, walking with no additional head motions and with augmented head rotations in yaw for 7 m (WwHT), and an obstacle avoidance task, the Functional Mobility Test (FMT). Subjects wore a 3-D motion sensor centered at mid-torso to capture kinematic measures. Patients and normals differed significantly on some behavioral measures, such as the number of steps to perform TW, and on some but not all kinematic measures. ROC analyses, however, were at best only moderate, and failed to find strong differences and cut-points that would differentiate the groups. These findings suggest that although patients and normals differ in performance of these tests in some interesting ways the groups are not sufficiently different on these tests for easy use as screening tests to differentiate the populations.

  4. 10 CFR 431.304 - Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... consumption of walk-in coolers and walk-in freezers. 431.304 Section 431.304 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers Test Procedures § 431.304 Uniform test method for the measurement of...

  5. 10 CFR 431.304 - Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... consumption of walk-in coolers and walk-in freezers. 431.304 Section 431.304 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers Test Procedures § 431.304 Uniform test method for the measurement of...

  6. 10 CFR 431.304 - Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... consumption of walk-in coolers and walk-in freezers. 431.304 Section 431.304 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers Test Procedures § 431.304 Uniform test method for the measurement of...

  7. 10 CFR 431.304 - Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in freezers. 431.304 Section 431.304 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers Test Procedures...

  8. Walking tests during the exercise training: specific use for the cardiac rehabilitation.

    PubMed

    Casillas, J-M; Hannequin, A; Besson, D; Benaïm, S; Krawcow, C; Laurent, Y; Gremeaux, V

    2013-10-01

    Walk tests, principally the six-minute walk test (6mWT), constitute a safe, useful submaximal tool for exercise tolerance testing in cardiac rehabilitation (CR). The 6mWT result reflects functional status, walking autonomy and efficacy of CR on walking endurance, which is more pronounced in patients with low functional capacity (heart failure - cardiac surgery). The 6mWT result is a strong predictor of mortality. However, clinically significant changes and reliability are still subject to debate - probably because of the ambiguity in terms of the target speed (either comfortable or brisk walking). Of the other time-based walk tests, the 2-minute-walk test is the only one applicable during CR, reserved for patients with severe disabilities by its psychometric properties. Fixed-distance tests (principally the 200m fast walk test) and incremental shuttle walking, tests explore higher levels of effort and may represent a safe and inexpensive alternative to laboratory-based tests during CR. These walking tests may be useful for personalizing prescription of training programs. However, the minimum clinically significant difference has not yet been determined. Lastly, walking tests appear to be potential useful tools in promoting physical activity and behavioural changes at home. Thus, validation of other walk tests with better psychometric properties will be necessary.

  9. Evidence for the different physiological significance of the 6- and 2-minute walk tests in multiple sclerosis

    PubMed Central

    2012-01-01

    Background Researchers have recently advocated for the 2-minute walk (2MW) as an alternative for the 6-minute walk (6MW) to assess long distance ambulation in persons with multiple sclerosis (MS). This recommendation has not been based on physiological considerations such as the rate of oxygen consumption (V·O2) over the 6MW range. Objective This study examined the pattern of change in V·O2 over the range of the 6MW in a large sample of persons with MS who varied as a function of disability status. Method Ninety-five persons with clinically-definite MS underwent a neurological examination for generating an Expanded Disability Status Scale (EDSS) score, and then completion of the 6MW protocol while wearing a portable metabolic unit and an accelerometer. Results There was a time main effect on V·O2 during the 6MW (p = .0001) such that V·O2 increased significantly every 30 seconds over the first 3 minutes of the 6MW, and then remained stable over the second 3 minutes of the 6MW. This occurred despite no change in cadence across the 6MW (p = .84). Conclusions The pattern of change in V·O2 indicates that there are different metabolic systems providing energy for ambulation during the 6MW in MS subjects and steady state aerobic metabolism is reached during the last 3 minutes of the 6MW. By extension, the first 3 minutes would represent a test of mixed aerobic and anaerobic work, whereas the second 3 minutes would represent a test of aerobic work during walking. PMID:22380843

  10. 75 FR 55067 - Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In Freezers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-09

    ...The U.S. Department of Energy (DOE) previously published a notice of proposed rulemaking to adopt test procedures for measuring the energy consumption of walk-in coolers and walk-in freezers, pursuant to the Energy Policy and Conservation Act (EPCA), as amended. DOE is continuing to consider those proposals, but is now soliciting comments on several alternative proposed options. Once any final......

  11. Reproducibility of the six-minute walk test and Glittre ADL-test in patients hospitalized for acute and exacerbated chronic lung disease

    PubMed Central

    José, Anderson; Dal Corso, Simone

    2015-01-01

    Background: The 6-minute walk test (6MWT) and the Glittre ADL-test (GT) are used to assess functional capacity and exercise tolerance; however, the reproducibility of these tests needs further study in patients with acute lung diseases. Objectives: The aim of this study was to investigate the reproducibility of the 6MWT and GT performed in patients hospitalized for acute and exacerbated chronic lung diseases. Method: 48 h after hospitalization, 81 patients (50 males, age: 52±18 years, FEV1: 58±20% of the predicted value) performed two 6MWTs and two GTs in random order on different days. Results: There was no difference between the first and second 6MWT (median 349 m [284-419] and 363 m [288-432], respectively) (ICC: 0.97; P<0.0001). A difference between the first and second tests was found in GT (median 286 s [220-378] and 244 s [197-323] respectively; P<0.001) (ICC: 0.91; P<0.0001). Conclusion: Although both the 6MWT and GT were reproducible, the best results occurred in the second test, demonstrating a learning effect. These results indicate that at least two tests are necessary to obtain reliable assessments. PMID:26039036

  12. Validation of the English version of the Walking Estimated-Limitation Calculated by History (WELCH) questionnaire in patients with intermittent claudication.

    PubMed

    Tew, Garry A; Nawaz, Shah; Humphreys, Liam; Ouedraogo, Nafi; Abraham, Pierre

    2014-02-01

    The Walking Estimated-Limitation Calculated by History (WELCH) questionnaire has recently been proposed as a valid and simple instrument for assessing walking limitation in patients with intermittent claudication. The aim of this study was to validate an English version of the WELCH questionnaire in an English native population. Thirty-nine patients (ankle-brachial index 0.59 ± 0.16, age 65 ± 11 years, 82% male) completed an English version of the WELCH questionnaire. Maximum walking distance was measured objectively using the Gardner-Skinner treadmill test and the 6-minute walk test. The median WELCH score was 24 (9-39). Maximum walking distances were 412 m (149-675 m) for the treadmill test and 381 ± 88 m for the 6-minute walking test. The Spearman's correlation coefficient was ρ = 0.59 between the WELCH score and treadmill distance (p < 0.001) and ρ = 0.82 between the WELCH score and 6-minute walk distance (p < 0.001). These findings suggest that the English version of the WELCH questionnaire is a valid instrument for assessing walking impairment in patients with intermittent claudication.

  13. Multidirectional walk test in individuals with Parkinson's disease: a validity study.

    PubMed

    Bryant, Mon S; Workman, Craig D; Jackson, George R

    2015-03-01

    Gait parameters of forward, backward, and sideways walk were studied when the participants walked overground in four directions at their self-selected speed and were compared with walking in the four directions on an instrumented GAITRite walkway. Intraclass correlation coefficients between the overground walk test measures and the instrumented walkway measures of gait speed, cadence, and stride length for the forward walk were 0.85, 0.88, and 0.87, respectively. For the backward walk, the coefficients were 0.91 for gait speed, 0.75 for cadence, and 0.93 for stride length. For the sideways walk, the coefficients were 0.92 for gait speed, 0.93 for cadence, and 0.94 for stride length. Gait parameters of forward, backward, and sideways walk obtained by the overground walk test had excellent agreement with those obtained by the instrumented walkway. The quick timed test provided quantitative data for gait evaluation and was valid for clinical use.

  14. Vascular Reactivity is Impaired and Associated With Walking Ability in Patients With Intermittent Claudication.

    PubMed

    Silva, Rita de Cassia Gengo E; Wolosker, Nelson; Yugar-Toledo, Juan Carlos; Consolim-Colombo, Fernanda Marciano

    2015-08-01

    We verified whether vascular reactivity is impaired and whether there is any association between vascular reactivity, walking ability, and peripheral artery disease (PAD) severity in patients with intermittent claudication (IC). We studied 63 patients and 17 age- and sex-matched volunteers without PAD. Vascular reactivity was evaluated in the brachial artery during reactive hyperemia (flow-mediated dilation [FMD]) and after a sublingual single dose of nitroglycerin (nitroglycerin-induced vasodilation [NID]). Walking ability was verified by a 6-minute walk test. Vascular reactivity and walking ability were significantly worse in patients with IC compared with control participants. The ankle-brachial index correlated with FMD, NID, as well as total and pain-free distances. The NID and walking ability progressively decreased as PAD severity increased. Walking ability correlated with NID but not with FMD. In patients with IC, vascular reactivity is impaired and is related to the severity of PAD and to walking ability.

  15. Knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae.

    PubMed

    Orr, Caley M

    2005-11-01

    Appeals to synapomorphic features of the wrist and hand in African apes, early hominins, and modern humans as evidence of knuckle-walking ancestry for the hominin lineage rely on accurate interpretations of those features as adaptations to knuckle-walking locomotion. Because Gorilla, Pan, and Homo share a relatively close common ancestor, the interpretation of such features is confounded somewhat by phylogeny. The study presented here examines the evolution of a similar locomotor regime in New World anteaters (order Xenarthra, family Myrmecophagidae) and uses the terrestrial giant anteater (Myrmecophaga tridactyla) as a convergence test of adaptation for purported knuckle-walking features of the Hominidae. During the stance phase of locomotion, Myrmecophaga transmits loads through flexed digits and a vertical manus, with hyperextension occurring at the metacarpophalangeal joints of the weight-bearing rays. This differs from the locomotion of smaller, arboreal anteaters of outgroup genera Tamandua and Cyclopes that employ extended wrist postures during above-branch quadrupedality. A number of features shared by Myrmecophaga and Pan and Gorilla facilitate load transmission or limit extension, thereby stabilizing the wrist and hand during knuckle-walking, and distinguish these taxa from their respective outgroups. These traits are a distally extended dorsal ridge of the distal radius, proximal expansion of the nonarticular surface of the dorsal capitate, a pronounced articular ridge on the dorsal aspects of the load-bearing metacarpal heads, and metacarpal heads that are wider dorsally than volarly. Only the proximal expansion of the nonarticular area of the dorsal capitate distinguishes knuckle-walkers from digitigrade cercopithecids, but features shared with digitigrade primates might be adaptive to the use of a vertical manus of some sort in the stance phase of terrestrial locomotion. The appearance of capitate nonarticular expansion and the dorsal ridge of the

  16. The Impact of Walking Exercises and Resistance Training upon the Walking Distance in Patients with Chronic Lower Limb Ischaemia

    PubMed Central

    Oszkinis, Grzegorz

    2016-01-01

    Objective. The objective of this paper is to compare the impact of supervised walking and resistance training upon the walking distance in PAD patients. Materials and Methods. The examination involved 50 PAD patients at the 2nd stage of the disease according to Fontaine's scale. The participants were randomly allocated to two groups: one exercising on the treadmill (n = 24) and one performing resistance exercises of lower limbs (n = 26). Results. The 12-week program of supervised rehabilitation led to a significant increase in the intermittent claudication distance measured both on the treadmill and during the 6-minute walking test. The group training on the treadmill showed a statistically significant increase of the initial claudication distance (ICD) and the absolute claudication distance (ACD) measured on the treadmill, as well as of ICD and the total walking distance (TWD) measured during the 6-minute walking test. Within the group performing resistance exercises, a statistically significant improvement was observed in the case of parameters measured on the treadmill: ICD and ACD. Conclusions. The supervised rehabilitation program, in the form of both walking and resistance exercises, contributes to the increase in the intermittent claudication distance. The results obtained in both groups were similar. PMID:27833919

  17. The Impact of Walking Exercises and Resistance Training upon the Walking Distance in Patients with Chronic Lower Limb Ischaemia.

    PubMed

    Szymczak, Maria; Oszkinis, Grzegorz; Majchrzycki, Marian

    2016-01-01

    Objective. The objective of this paper is to compare the impact of supervised walking and resistance training upon the walking distance in PAD patients. Materials and Methods. The examination involved 50 PAD patients at the 2nd stage of the disease according to Fontaine's scale. The participants were randomly allocated to two groups: one exercising on the treadmill (n = 24) and one performing resistance exercises of lower limbs (n = 26). Results. The 12-week program of supervised rehabilitation led to a significant increase in the intermittent claudication distance measured both on the treadmill and during the 6-minute walking test. The group training on the treadmill showed a statistically significant increase of the initial claudication distance (ICD) and the absolute claudication distance (ACD) measured on the treadmill, as well as of ICD and the total walking distance (TWD) measured during the 6-minute walking test. Within the group performing resistance exercises, a statistically significant improvement was observed in the case of parameters measured on the treadmill: ICD and ACD. Conclusions. The supervised rehabilitation program, in the form of both walking and resistance exercises, contributes to the increase in the intermittent claudication distance. The results obtained in both groups were similar.

  18. Preliminary study of novel, timed walking tests for children with spina bifida or cerebral palsy

    PubMed Central

    Kane, Kyra J; Lanovaz, Joel; Bisaro, Derek; Oates, Alison; Musselman, Kristin E

    2016-01-01

    Objective: Walking assessment is an important aspect of rehabilitation practice; yet, clinicians have few psychometrically sound options for evaluating walking in highly ambulatory children. The purpose of this study was to evaluate the validity and reliability of two new measures of walking function—the Obstacles and Curb tests—relative to the 10-Meter Walk test and Timed Up and Go test in children with spina bifida or cerebral palsy. Methods: A total of 16 ambulatory children with spina bifida (n=9) or cerebral palsy (n=7) (9 boys; mean age 7years, 7months; standard deviation 3years, 4months) and 16 age- and gender-matched typically developing children participated. Children completed the walking tests, at both self-selected and fast speeds, twice. To evaluate discriminative validity, scores were compared between typically developing and spina bifida/cerebral palsy groups. Within the spina bifida/cerebral palsy group, inter-test correlations evaluated convergent validity and intraclass correlation coefficients evaluated within-session test–retest reliability. Results: At fast speeds, all tests showed discriminative validity (p<0.006 for typically developing and spina bifida/cerebral palsy comparisons) and convergent validity (rho=0.81–0.90, p⩽0.001, for inter-test correlations). At self-selected speeds, only the Obstacles test discriminated between groups (p=0.001). Moderately strong correlations (rho=0.73–0.78, p⩽0.001) were seen between the 10-Meter Walk test, Curb test, and Timed Up and Go test. Intraclass correlation coefficients ranged from 0.81 to 0.97, with higher test–retest reliability for tests performed at fast speeds rather than self-selected speeds. Conclusion: The Obstacles and Curb tests are promising measures for assessing walking in this population. Performing tests at fast walking speeds may improve their validity and test–retest reliability for children with spina bifida/cerebral palsy. PMID:27493754

  19. Reference values for the incremental shuttle walk test in healthy subjects: from the walk distance to physiological responses *,**

    PubMed Central

    Dourado, Victor Zuniga; Guerra, Ricardo Luís Fernandes; Tanni, Suzana Erico; Antunes, Letícia Cláudia de Oliveira; Godoy, Irma

    2013-01-01

    OBJECTIVE: To determine reference values for incremental shuttle walk distance (ISWD) and peak physiological responses during the incremental shuttle walk test (ISWT), as well as to develop a series of predictive equations for those variables in healthy adults. METHODS: We evaluated 103 healthy participants ≥ 40 years of age (54 women and 49 men). We fitted each participant with a gas analysis system for use during the ISWT. Oxygen consumption (VO2), carbon dioxide production, minute ventilation, heart rate (HR), ISWD, and maximal walking velocity (MWV) were obtained as primary outcomes. We also assessed hand grip strength (HGS) and lean body mass (LBM). RESULTS: The regression analysis models, including physiological variables, ISWD, and MWV (adjusted for age, body mass, height, and sex), produced R2 values ranging from 0.40 to 0.65 (for HR and peak VO2, respectively). Using the models including LBM or HGS, we obtained no significant increase in the R2 values for predicting peak VO2, although the use of those models did result in slight increases in the R2 values for ISWD and MWV (of 8% and 12%, respectively). The variables ISWD, MWV, and ISWD × body mass, respectively, explained 76.7%, 73.3%, and 81.2% of peak VO2 variability. CONCLUSIONS: Our results provide reference values for ISWD and physiological responses to the ISWT, which can be properly estimated by determining simple demographic and anthropometric characteristics in healthy adults ≥ 40 years of age. The ISWT could be used in assessing physical fitness in the general adult population and in designing individualized walking programs. PMID:23670504

  20. Exploring adaptations to the modified shuttle walking test

    PubMed Central

    Woolf-May, Kate; Meadows, Steve

    2013-01-01

    Objective The 10 m modified shuttle walking test (MSWT) is recommended to determine the functional capacity in older individuals and for patients entering cardiac rehabilitation. Participants are required to negotiate around cones set 1 m from the end markers. However, consistent comments indicate that for some individuals manoeuvring around the cones can be quite difficult. Therefore, the objective of this study was to explore differences within and between non-cardiac and postmyocardial infarction (MI) males during MSWT with and without the cones. Design Comparative study. Participants 20 post-MI (64.8±6.6, range 51–74 years) and 20 non-cardiac male controls (64.1±5.7, range 52–74 years) participated. Methods Participants performed MSWT with and without cones. Throughout, the participants expired air, and the heart rate (bpm) (HR) and ratings of perceived exertion (RPE) were measured. Participant protocol preference was recorded verbatim. Results One-way analysis of variance found no significant difference in VO2 peak (cones 20.4±5.1 vs no-cones 21.9±4.8 ml/kg/min, p=0.197) or distance ambulated (cones 631.8±132.9 m vs no-cones 662.4±164.1 m, p=0.371) between protocols or groups. Analysis comparing lines of regression showed a significant trajectory difference in VO2 (ml/kg/min) (p<0.01) between protocols with higher HR (p<0.01) and respiratory exchange ratio (RER, p<0.001) values during cones. RPEs were higher for post-MIs versus controls during both protocols (p<0.05). Post-MIs taking β-blockers produce significantly lower HR values. The χ2 analysis found no significant difference in protocol preference (no-cones: all n=25, 63%; post-MIs n=13, 65%; and controls n=12, 60%). Conclusions Post-MIs found both protocols subjectively harder than controls with no significant difference in the VO2 peak. However, both groups worked at a lesser percentage of their anaerobic threshold during no-cones protocol as indicated by lower RER values

  1. Six-Minute Walk Test for Persons with Mild or Moderate Disability from Multiple Sclerosis: Performance and Explanatory Factors

    PubMed Central

    Fry, Donna K.; Pfalzer, Lucinda A.

    2011-01-01

    ABSTRACT Purpose: The primary purpose of this study was to determine the extent to which health factors, functional measures, and pulmonary impairment explain performance on 6-Minute Walk Test (6MWT) distance in ambulatory persons with multiple sclerosis (MS). Another purpose was to determine the effect of disability and age on 6MWT performance and explanatory factors. Methods: A cross-sectional study design was used to evaluate factors that explain performance on the 6MWT in 64 community-dwelling persons with MS-related disability (Expanded Disability Status Scale [EDSS] 3.8±1.6). Of the 64 participants, 43 (67.2%) exhibited mild disability (EDSS <4.0) and 21 (32.8%) had moderate disability (EDSS 4.0–6.5). A regression analysis compared 6MWT performance to measures of health factors (EDSS, number of medications, number of comorbidities, resting HR, systolic and diastolic blood pressure [BP]); physical performance (functional stair test [FST], sit-to-stand test [SST], static standing balance [BAL], Fatigue Severity Scale [FSS], Activities-specific Balance Confidence [ABC] Scale); and pulmonary function (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], maximal voluntary ventilation [MVV], maximal inspiratory pressure [MIP], maximal expiratory pressure [MEP]). Results: EDSS, ABC, FST, SST, BAL, MVV, MIP, and MEP were significantly associated with 6MWT distance after adjusting for age. Multiple step-wise linear regression analysis revealed that ABC, FST, and BAL were significant and independent explanatory factors of 6MWT distance. ABC and FST explained 75% of the variance in 6MWT performance (R2=0.75). Curvilinear regression analysis revealed that the FST is the most significant explanatory factor for 6MWT distance, explaining 79% of the variance (R2=0.79). Conclusions: 6MWT performance in persons with MS was explained by balance confidence (ABC) and stair-climbing ability (FST). The ABC and FST may be practical clinical measures for

  2. The Walking Trail-Making Test is an early detection tool for mild cognitive impairment

    PubMed Central

    Perrochon, Anaick; Kemoun, Gilles

    2014-01-01

    Background Executive function impairment (in particular, mental flexibility) in the elderly, and in patients with mild cognitive impairment (MCI), is strongly correlated with difficulties in performing complex walking tasks. The aim of this study was to determine if the adaptation of a neuropsychological test (the Trail-Making Test), to evaluate executive functions during walking, can be an early detection tool for cognitive impairment. Methods Fifty subjects (15 young, 20 older, presumably healthy, and 15 MCI) were first evaluated for cognitive functions (Mini-Mental State Examination, Frontal Assessment Battery, and Trail-Making Test) and motor functions (10-meter walking test). All subjects then performed a spatial navigation, or a complex walking test (the Walking Trail-Making Test: [WTMT]), and their spatiotemporal walking variables were analyzed using cluster analysis. Results Following evaluation of WTMT locomotor performance, cluster analysis revealed three groups that were distinctly different in age and cognitive abilities: a group of young subjects, a group of healthy older subjects, MCI subjects with amnestic impairment, and a group of MCI subjects with executive function impairment. The WTMT enabled early detection, (ie, borderline MCI) of dysexecutive impairment, with 78% sensitivity and 90% specificity. Conclusion The WTMT is of interest in that it can help provide early detection of dysexecutive cognitive impairment. PMID:24426778

  3. Influence of a visual-verbal Stroop test on standing and walking performance of older adults.

    PubMed

    Wollesen, B; Voelcker-Rehage, C; Regenbrecht, T; Mattes, K

    2016-03-24

    The dual task (DT) paradigm has been used to investigate decrements in balance performance while walking and standing in fall prevention studies with older adults. However, there are inconsistent findings whether balance performance decreases or increases in DT situations. Following different theoretical models (e.g. limited resource hypothesis or cross domain competition model), these inconsistent findings can be explained by task settings and task complexity. We compared DT performance in an executive control task (Stroop test) while standing and walking to analyze which theoretical model would fit our data best. Twenty-eight persons (>65 years) were examined under single task (ST) and DT conditions for standing (sway length and sway velocity) and walking (step length, step width (SW), peak forces of the heel, mid- and forefoot). SW increased from ST to DT conditions, and step length decreased significantly. Maximum forces of the forefoot were reduced whereas the maximum forces of the midfoot increased. Additionally, correct answers of the Stroop test decreased from the ST baseline condition to DT walking. No correlations were found between DT costs (performance decrements) of standing and walking. For both conditions (standing and walking), the limited resources hypothesis fits best. Moreover, not all modified gait variables could be defined as negative DT costs. Increased SW and decreased step length might be used to compensate influences on lateral stability while demands on motor-cognitive resources increase. Further, drawing conclusions from a standing task for walking conditions might lead to misinterpretations.

  4. Accelerometry and Its Association With Objective Markers of Walking Limitations in Ambulatory Adults With Multiple Sclerosis

    PubMed Central

    Motl, Robert W.; Dlugonski, Deirdre; Suh, Yoojin; Weikert, Madeline; Fernhall, Bo; Goldman, Myla

    2011-01-01

    Objective To validate accelerometry based on its correlations with 6-minute walk distance (6MWD) and oxygen cost of walking as objective markers of walking limitations in multiple sclerosis (MS). Design Cross-sectional. Setting Laboratory and general community. Participants Ambulatory participants with MS (N=26) who resided in the local community. Interventions Not applicable. Main Outcome Measures Patient Determined Disease Steps (PDDS) scale and Multiple Sclerosis Walking Scale-12 (MSWS-12); 6-minute walk test while wearing a portable metabolic unit for measuring the 6MWD and oxygen cost of walking; accelerometer during the waking hours of a 7-day period. Results The average of total daily movement counts from the accelerometer correlated significantly and strongly with MSWS-12 scores (ρ−.681, P=.001), PDDS scores (ρ−.609, P=.001), 6MWD (ρ.519, P=.003), and oxygen cost of walking (ρ−.541, P=.002). Conclusions We provide evidence that further supports the validity of accelerometry as a measure of walking limitations in ambulatory persons with MS. PMID:21112438

  5. Determinants of distance walked during the six-minute walk test in patients undergoing cardiac surgery at hospital discharge

    PubMed Central

    2014-01-01

    Introduction The aim of this study was to identify the determinants of distance walked in six-minute walk test (6MWD) in patients undergoing cardiac surgery at hospital discharge. Methods The assessment was performed preoperatively and at discharge. Data from patient records were collected and measurement of the Functional Independence Measure (FIM) and the Nottingham Health Profile (NHP) were performed. The six-minute walk test (6MWT) was performed at discharge. Patients undergoing elective cardiac surgery, coronary artery bypass grafting or valve replacement were eligible. Patients older than 75 years who presented arrhythmia during the protocol, with psychiatric disorders, muscular or neurological disorders were excluded from the study. Results Sixty patients (44.26% male, mean age 51.53 ± 13 years) were assessed. In multivariate analysis the following variables were selected: type of surgery (P = 0.001), duration of cardiopulmonary bypass (CPB) (P = 0.001), Functional Independence Measure - FIM (0.004) and body mass index - BMI (0.007) with r = 0.91 and r2 = 0.83 with P < 0.001. The equation derived from multivariate analysis: 6MWD = Surgery (89.42) + CPB (1.60) + MIF (2.79 ) - BMI (7.53) - 127.90. Conclusion In this study, the determinants of 6MWD in patients undergoing cardiac surgery were: the type of surgery, CPB time, functional capacity and body mass index. PMID:24885130

  6. Feasibility and Reliability of Two Different Walking Tests in People with Severe Intellectual and Sensory Disabilities

    ERIC Educational Resources Information Center

    Waninge, A.; Evenhuis, I. J.; van Wijck, R.; van der Schans, C. P.

    2011-01-01

    Background: The purpose of this study is to describe feasibility and test-retest reliability of the six-minute walking distance test (6MWD) and an adapted shuttle run test (aSRT) in persons with severe intellectual and sensory (multiple) disabilities. Materials and Methods: Forty-seven persons with severe multiple disabilities, with Gross Motor…

  7. Heart rate recovery after the 6-min walk test is related to 6-min walk distance and percutaneous oxygen saturation recovery in patients with COPD.

    PubMed

    Shiroishi, Ryota; Kitagawa, Chika; Miyamoto, Naomi; Kakuno, Nao; Koyanagi, Harumi; Rikitomi, Naoto; Senjyu, Hideaki

    2015-05-01

    Heart rate recovery (HRR) after maximal load exercise affects mortality in chronic obstructive pulmonary disease (COPD). However, the associations of clinical characteristics with HRR after the 6-min walk test (6MWT), which is defined as a submaximal load test, remain unclear. We showed that HRR in patients with COPD after 6MWT was related to 6-min walk distance and percutaneous oxygen saturation recovery. HRR after the 6MWT may be useful to assess exercise capacity in COPD.

  8. Predicting habitual walking performance in multiple sclerosis: relevance of capacity and self-report measures.

    PubMed

    Gijbels, Domien; Alders, Geert; Van Hoof, Elke; Charlier, Caroline; Roelants, Machteld; Broekmans, Tom; Eijnde, Bert Op 't; Feys, Peter

    2010-05-01

    The objective was to establish the extent to which physical functioning capacity and self-report measures are able to predict the habitual walking performance in ambulatory persons with multiple sclerosis. Fifty persons with multiple sclerosis (Expanded Disability Status Scale, EDSS, 1.5-6.5) were tested on leg muscle strength as well as walking and balance capacity, and completed self-report indices on perceived physical functioning. Habitual walking performance, that is, the real amount of steps that is performed in the customary living environment, was registered by means of an ambulant accelerometer-based monitor during seven consecutive days. Mild (EDSS 1.5-4.0, n = 29) and moderate (EDSS 4.5-6.5, n = 21) multiple sclerosis subgroups were additionally distinguished as predictor variables and values were hypothesized to differ depending on multiple sclerosis severity and concomitant ambulatory function. Multiple regression analyses yielded a single most significant predictor for each (sub)group with other variables making no independent contribution to the variation in habitual walking performance. For the total study sample, this was the 6-Minute Walking Test (R(2) = 0.458, p < 0.01). In the mild multiple sclerosis subgroup, the 6-Minute Walking Test was again most predictive, yet to a modest degree (R(2) = 0. 187, p = 0.02). In the moderate multiple sclerosis subgroup, the 2-Minute Walking Test explained over half of the variance (R(2) = 0.532, p < 0.01). Habitual walking performance is best reflected by longer walking capacity tests. The extent to which it can be predicted based on clinical testing is larger in a multiple sclerosis patient sample with more severe walking disability. Ambulatory monitoring, however, includes aspects of community ambulation not captured in the clinic, and must be considered as an additional outcome for evaluating interventions in multiple sclerosis.

  9. Physiologic responses during the six minute walk test in obese and non-obese COPD patients.

    PubMed

    Bautista, Jennifer; Ehsan, Mohsin; Normandin, Edgar; Zuwallack, Richard; Lahiri, Bimalin

    2011-08-01

    Although obesity is a common co-morbid condition in COPD, relatively little is known how it may affect functional exercise capacity. Accordingly, we compared physiologic responses during a 6 min walk test in 10 obese and 10 non-obese COPD patients matched by gender, age, and spirometric severity category. Patients first exercised on a treadmill to determine maximal exercise responses, then following a rest period they completed a 6 min walk test. Breath by-breath analyses of expired air via a facemask was obtained using a portable, battery operated device. Oxygen consumption (VO(2)), carbon dioxide production (VCO(2)), tidal volume (VT), respiratory rate (RR), minute ventilation (VE), and inspiratory capacity (IC) were compared. The mean FEV1 in the obese and non-obese groups was 52 ± 13 and 58 ± 18 percent of predicted, respectively, and the BMI of the obese patients was 37 ± 02 kg/m(2). Obese patients had shorter 6 min walk distances than non-obese patients (247 ± 73 vs 348 ± 51 m, respectively, p = 0.003), but walk-work, defined as 6 min walk distance × weight (in kg), was not different. There were no significant between-group differences in any exercise variable measured during the 6 min walk test. In both groups, VO(2) and VE increased linearly over the first 2-3 min, then plateaued at approximately 80% of maximum. Although 6 min walk distance is shorter in obese COPD patients, their physiologic responses are similar to those of non-obese patients.

  10. The weighted walking test as an alternative method of assessing aerobic power.

    PubMed

    Klimek, Andrzej T; Klimek, Adam

    2007-01-15

    The aim of the present study was to determine maximal oxygen uptake (VO2max) directly during uphill walking exercise and to compare these values with those achieved during running and cycling exercise. Forty untrained students (20 males and 20 females) took part in three exercise tests. The running test was performed on a horizontal treadmill and the speed was gradually increased by 0.3 m . s(-1) every 3 min. The walking test was conducted on a treadmill inclined at 12% (speed of 1.8 m . s(-1)). The load was further increased every 3 min by the addition of a mass of one-twentieth of the body mass of the participant (plastic containers filled with water and added to a backpack carried by the participant). During the bicycle ergometry test, the workload was increased by 20 W every 2 min. All tests were performed until volitional exhaustion. During all tests, oxygen uptake, minute ventilation, tidal volume, respiratory frequency, heart rate, hydrogen ion concentration, base excess, and blood lactate concentration were analysed. The Pearson correlation coefficients between the weighted walking test and the commonly applied running and bicycle ergometry tests indicate a strong association with the new test in evaluating maximal oxygen uptake. The negligible differences in VO2max between the three tests for the male participants (running: 61.0 ml . kg(-1) . min(-1); walking: 60.4 ml . kg(-1) . min(-1); cycling: 60.2 ml . kg(-1) . min(-1)), and the fact that the females achieved better results on the walking test than the cycle ergometer test (running: 45.0 ml . kg(-1) . min(-1); walking: 42.6 ml . kg(-1) . min(-1); cycling: 40.1 ml . kg(-1) . min(-1)), confirm the suitability of the new method for evaluating aerobic power. The weighted walking test could be useful in the assessment of aerobic power in individuals for whom running is not advised or is difficult. In addition, the new test allows for determination of VO2max on small treadmills with a limited speed regulator

  11. Evaluating Walking in Patients with Multiple Sclerosis

    PubMed Central

    Bennett, Susan

    2011-01-01

    Walking limitations are among the most visible manifestations of multiple sclerosis (MS). Regular walking assessments should be a component of patient management and require instruments that are appropriate from the clinician's and the patient's perspectives. This article reviews frequently used instruments to assess walking in patients with MS, with emphasis on their validity, reliability, and practicality in the clinical setting. Relevant articles were identified based on PubMed searches using the following terms: “multiple sclerosis AND (walking OR gait OR mobility OR physical activity) AND (disability evaluation)”; references of relevant articles were also searched. Although many clinician- and patient-driven instruments are available, not all have been validated in MS, and some are not sensitive enough to detect small but clinically important changes. Choosing among these depends on what needs to be measured, psychometric properties, the clinical relevance of results, and practicality with respect to space, time, and patient burden. Of the instruments available, the clinician-observed Timed 25-Foot Walk and patient self-report 12-Item Multiple Sclerosis Walking Scale have properties that make them suitable for routine evaluation of walking performance. The Dynamic Gait Index and the Timed Up and Go test involve other aspects of mobility, including balance. Tests of endurance, such as the 2- or 6-Minute Walk, may provide information on motor fatigue not captured by other tests. Quantitative measurement of gait kinetics and kinematics, and recordings of mobility in the patient's environment via accelerometry or Global Positioning System odometry, are currently not routinely used in the clinical setting. PMID:24453700

  12. Clinical utility of the 6-min walk test for patients with moderate Parkinson's disease.

    PubMed

    Kobayashi, Eiji; Himuro, Nobuaki; Takahashi, Mitsuhiko

    2017-03-01

    The aim of this study was to test the clinical utility of the 6-min walk test (6MWT) for patients with moderate Parkinson's disease (PD) through a determination of factors related to this test. This was a descriptive, observational study carried out at a General Hospital, in-patients. Twenty-four patients with moderate PD were studied. We used Hoehn and Yahr stage ratings (HY stage), Unified Parkinson Disease Rating Scales (UPDRS) motor examination score, 6MWT, Berg Balance scale, Timed 'Up & Go' test (TUG), 10-m walk test (10-m walk speed, 10-m walk steps and cadence), and the energy cost of walking (Ec). The average HY stage was 3.1±0.5 and 6MWT was 340.8±110.9 m. TUG (r=-0.68, P<0.01) and Ec (r=-0.65, P<0.01) were correlated significantly with 6MWT. Multiple regression analysis with age, HY stage, TUG, cadence, and Ec as variables indicated a significant degree of variability in the 6MWT results (R=0.77, P<0.001). The TUG (β=-0.47, P<0.01) and Ec (β=-0.4, P<0.01) were correlated independently with the 6MWT results. In contrast, age, HY stage, and cadence were not independently correlated. The 6MWT is a simple tool for assessing walking capacity for patients with PD. In this study, we confirmed the convergent validity and clinical utility of the 6MWT for patients with moderate PD. The 6MWT is useful for clinical assessment to guide the planning of rehabilitation treatment for patients with moderate PD.

  13. Walk on Floor Eyes Closed Test: A Unique Test of Spaceflight Induced Ataxia

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Fisher, E. A.; Kofman, I. S.; Cerisano, J. M.; Harm, D. L.; Bloomberg, J. J.

    2011-01-01

    Measurement and quantification of posture and locomotion following spaceflight is an evolving process. Based on the data obtained from the current investigation we believe that the walk on the floor line test with the eyes closed (WOFEC) provides a unique procedure for quantifying postflight ataxia. As a part of an ongoing investigation designed to look at functional changes in astronauts returning from spaceflight seven astronauts (5 short duration with flights of 12-16 days; 2 long duration crewmembers with flights of 6 months) were tested twice before flight, on landing day (short duration only), and 1, 6, and 30 days after flight. The WOFEC consisted of walking for 10 steps (repeated twice) with the feet heel to toe in tandem, arms folded across the chest and the eyes closed. The performance metric (scored by three examiners from video) was the percentage of correct steps completed over the three trials. A step was not counted as correct if the crewmember side-stepped, opened their eyes, or paused for more than three seconds between steps. The data reveled a significant decrease in percentage of correct steps on landing day (short duration crew) and on the first day following landing (long duration) with partial recovery the following day, and full recovery beginning on day sixth after flight. Both short and long duration fliers appeared to be unaware of foot position relative to their bodies or the floor. Postflight, deviation from a straight path was common, and seemed to be determined by the angle of foot placement relative to their body. While deviation from a straight line could be either left or right, primary deviations were observed to occur to the right. Furthermore, the test for two crewmembers elicited motion sickness symptoms. These data clearly demonstrate the sensorimotor challenges facing crewmembers after returning from spaceflight. The WOFEC test has value providing the investigator or crew surgeon with a simple method to quantify vestibular

  14. Development and Psychometric Testing of the Dogs and WalkinG Survey (DAWGS)

    ERIC Educational Resources Information Center

    Richards, Elizabeth A.; McDonough, Meghan H.; Edwards, Nancy E.; Lyle, Roseann M.; Troped, Philip J.

    2013-01-01

    Purpose: Dog owners represent 40% of the population, a promising audience to increase population levels of physical activity. The purpose of this study was to develop and test the psychometric properties of a new instrument to assess social-cognitive theory constructs related to dog walking. Method: Dog owners ("N" = 431) completed the…

  15. Validation of the Rockport Fitness Walking Test in College Males and Females.

    ERIC Educational Resources Information Center

    Dolgener, Forrest A.; And Others

    1994-01-01

    This study attempted to validate the Rockport Fitness Walking Test (RFWT) in college students and develop prediction equations if the RFWT proved invalid. Researchers compared measured maximal oxygen uptake (VO2max) and VO2max predicted from previous equations. The original RFWT overpredicted VO2max in college students and thus is invalid for that…

  16. Modified Six-Minute Walk Test: Number of Steps per Second

    PubMed Central

    Burioka, Naoto; Imada, Akari; Kiyohiro, Akiko; Sugitani, Fumika; Fujii, Takenori; Hosaka, Akari; Nakamoto, Sachiko; Amisaki, Takashi; Shimizu, Eiji

    2014-01-01

    ABSTRACT The 6-min walk test (6MWT) has been used to examine subjective dyspnea, predict mortality and measure clinical outcomes in studies of patients with chronic pulmonary or heart disease. Although the 6MWT is useful to assess the general ability to perform daily physical activity, it is difficult to evaluate time-dependent responses. To improve the 6MWT, we devised a new index, which is the number of steps walked per second (NSPS). We performed the 6MWT in 11 healthy subjects and 7 patients with chronic obstructive pulmonary disease (COPD) and calculated the NSPS. The mean NSPS was significantly higher in the healthy subjects than in the COPD patients, while the coefficient of variation of the NSPS was significantly smaller in healthy subjects compared with COPD patients. Calculation of the NSPS was useful to evaluate the walking pattern. This modified 6MWT may be helpful for assessing the efficacy of rehabilitation and drug therapy for COPD. PMID:25067880

  17. Comparison between the six-minute walk test and the six-minute step test in post stroke patients

    PubMed Central

    2013-01-01

    Background The Stroke remains one of the major chronic diseases worldwide, and is considered a major cause of disability, which results not only in persistent neurological deficits, but also in the high physical deconditioning, nevertheless there are not many forms of assessing functional capacity in this population. We aimed to investigate the feasibility of the Six Minute Walk Teste and the Six-Minute Step Test (6MST) in post-stroke patients and compare the behavior of physiological variables during the 6MST and the Six-Minute Walk Test (6MWT), by correlating the functional performance obtained in both tests. Method The 6MWT was carried out according to the American Thoracic Society (ATS) and the 6MST was performed in six minutes in order to compare it to the 6MWT in a 20 cm step. Was included post-stroke individuals able to walk without aid. All of them did the 6MWT and the 6MST. Results 12 patients participated in the study. There was no statistical difference in the parameters analyzed when tests were compared. There was poor correlation between the functional performance in both tests. Conclusion The 6MWT and the 6MST is feasible for post-stroke patients and physiological responses are equal during the performance of both tests. However, there was no correlation with respect to functional performance, which was assessed by the distance walked in the 6MWT and by the number of steps climbed in the 6MST. PMID:23924407

  18. The Six-Minute Walk Test for Adults with Intellectual Disability: A Study of Validity and Reliability

    ERIC Educational Resources Information Center

    Nasuti, Gabriella; Stuart-Hill, Lynneth; Temple, Viviene A.

    2013-01-01

    Background: The Six-Minute Walk Test (6MWT) has been used with clinical and healthy populations to assess functional capacity and cardiovascular fitness. The aim of this study was to determine the test-retest reliability of a modified-6MWT as well as concurrent validity of walk distance with peak oxygen uptake (VO[subscript 2] peak). Method:…

  19. 78 FR 20695 - Walk-Through Metal Detectors and Hand-Held Metal Detectors Test Method Validation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... Office of Justice Programs Walk-Through Metal Detectors and Hand-Held Metal Detectors Test Method... has recently developed updated versions of its minimum performance standards for walk-through metal detectors and hand-held metal detectors. In order to ensure that the test methods in the standards...

  20. How to carry out a field walking test in chronic respiratory disease

    PubMed Central

    Spruit, Martijn A.; Singh, Sally J.

    2015-01-01

    Educational Aims To provide recommendations for conducting field walking tests in people with chronic respiratory disease, from the new European Respiratory Society/American Thoracic Society Technical Standard To provide information to assist in selecting a field walking test in people with chronic respiratory disease. Key points The 6MWT, ISWT and ESWT are valid and reliable tests of functional exercise capacity in people with COPD. The 6MWT is also widely used in other chronic respiratory disorders. There is a learning effect for the 6MWT and ISWT, so two tests must be performed if the tests are being used to measure change over time, with the best distance recorded. The 6MWT is very sensitive to changes in the way it is conducted, including use of encouragement, provision of supplemental oxygen, changes in track layout and length, and use of wheeled walkers. These factors should be held constant when the test is repeated. The 6MWT, ISWT and ESWT are strenuous tests, with cardiorespiratory responses that are similar to those during a maximal incremental exercise test. As a result, the contraindications and precautions for these field walking tests should be the same as for a laboratory-based incremental exercise test. Summary The European Respiratory Society (ERS) and American Thoracic Society (ATS) have recently published a Technical Standard which documents the standard operating procedures for the 6-min walk test (6MWT), incremental shuttle walk test (ISWT) and endurance shuttle walk test (ESWT). The Technical Standard shows that all three tests are valid and reliable measures of functional exercise capacity in people with chronic respiratory disease and makes recommendations for standardising their performance. Key findings and recommendations of the Technical Standard include: The 6MWT, ISWT and ESWT are strenuous tests which elicit cardiorespiratory responses that are similar to those observed during a maximal incremental exercise test. As a result, the

  1. Reliability and feasibility of the six minute walk test in subjects with myotonic dystrophy.

    PubMed

    Kierkegaard, Marie; Tollbäck, Anna

    2007-12-01

    The objective was to describe test-retest reliability and feasibility of the six minute walk test in adult subjects with myotonic dystrophy type 1. Twelve subjects (28-68 years, mean 44) performed three six minute walk tests on two occasions, one week apart. Relative reliability was high (ICC(2.1)=0.99) and absolute reliability values were low (standard error of measurement 12 m, repeatability 33 m). Feasibility was investigated in a sample of 64 subjects (19-70 years, mean 43). Fifty-two subjects were able to perform two tests on the same day. Subjects with severe proximal weakness had difficulties performing repeated tests. A practice trial followed by a second test on the same day can be recommended for most subjects, and the best test should be used for evaluations. In conclusion, even though the study sample was small, the present study indicates that the six minute walk test is reliable and feasible in subjects with myotonic dystrophy type 1.

  2. Changes in cardiopulmonary function in normal adults after the Rockport 1 mile walking test: a preliminary study.

    PubMed

    Kim, Kyoung; Lee, Hye-Young; Lee, Do-Youn; Nam, Chan-Woo

    2015-08-01

    [Purpose] The purpose of this study was to investigate the changes of cardiopulmonary function in normal adults after the Rockport 1 mile walking test. [Subjects and Methods] University students (13 males and 27 females) participated in this study. Before and after the Rockport 1 mile walking test, pulmonary function, respiratory pressure, and maximal oxygen uptake were measured. [Results] Significant improvements in forced vital capacity and maximal inspiratory pressure were observed after the Rockport 1 mile walking test in males, and significant improvements in forced vital capacity, forced expiratory volume at 1 s, maximal inspiratory pressure, and maximal expiratory pressure were observed after the Rockport 1 mile walking test in females. However, the maximal oxygen uptake was not significantly different. [Conclusion] Our findings indicate that the Rockport 1 mile walking test changes cardiopulmonary function in males and females, and that it may improve cardiopulmonary function in middle-aged and older adults and provide basic data on cardiopulmonary endurance.

  3. Comparison of walking performance over the first 2 minutes and the full 6 minutes of the Six-Minute Walk Test

    PubMed Central

    2014-01-01

    Background Although the Six-Minute Walk Test (6MWT), as recommended by the American Thoracic Society, is widely used as a measure of functional endurance, it may not be applicable in some settings and populations. We sought to examine, therefore, performance over the first 2 minutes and the full 6 minutes of the 6MWT. Specifically, we investigated completion rates, distances walked, test-retest reliability, and the relationship between distances walked over the first 2 and the full 6 minutes of the 6MWT. Methods Community-dwelling children and adults age 3–85 years (n = 337) were asked to walk back and forth on a 15.24 meter (50 ft) course as far as possible without running over a 6 minute period. Test completion and the distance covered by the participants at 2 and 6 minutes were documented. The reliability of distances covered at 2 and 6 minutes was determined by retesting a subsample of 54 participants 6 to 10 days later. The relationship between distances covered at 2 and 6 minutes was determined for the 330 participants completing the 6MWT. Results All 337 participants completed at least 2 minutes of walking, but 7 children less than 5 years of age ceased walking before 6 minutes had elapsed. For the remaining 330 participants the mean distance walked was 186 meters at 2 minutes and 543 meters at 6 minutes. The distances covered at 2 and 6 minutes were reliable between sessions (intraclass correlation coefficients = 0.888 and 0.917, respectively). The distances covered over 2 and 6 minutes were highly correlated (r = 0.968). Conclusions The completion rate, values obtained, test-retest reliability, and relationship of the distances walked in 2 and 6 minutes support documentation of 2 minute distance during the 6MWT. The findings also provide support for use of a Two-Minute Walk Test as the endurance component in the Motor Battery of the NIH Toolbox. PMID:24767634

  4. Synthesis of two-dimensional human walking: a test of the lambda-model.

    PubMed

    Günther, Michael; Ruder, Hanns

    2003-08-01

    To test the lambda-model version of the equilibrium point hypothesis both for feasibility and validity with respect to the control of terrestrial locomotion, we developed a two-dimensional, eleven-segment musculoskeletal model of the human body including 14 muscle-tendon complexes per leg, three-segment feet, and a physiologically based model of foot-ground interaction. Human walking was synthesized by numerical integration of the coupled muscle-tendon and rigid body dynamics. To this end a control algorithm based on the lambda-model was implemented in the model providing muscle stimulation patterns that guaranteed dynamically stable walking including a balanced trunk. Thus, the timing of the movement is not preset by a central pattern generator but emerges from the interaction of the musculoskeletal system with the control algorithm. The control parameters were found in a trial-and-error approach. The feedforward part of the control scheme consists of just two target configurations each of which is composed of a set of one nominal length per muscle (lambda-model). Variation of gravity reveals that (1) the synthesized walking patterns are close to ballistic walking and (2) this muscularly induced natural walking can only be initiated and maintained in the range between about a tenth and three times earth-bound gravity. Our walking patterns are robust both against parameter variations and shuffling of the swing leg. We discuss our model with respect to gravity scaling, speed control, feedback delay, and the terms "equilibrium point hypothesis" and "central pattern generator."

  5. Daily intermittent hypoxia enhances walking after chronic spinal cord injury

    PubMed Central

    Hayes, Heather B.; Jayaraman, Arun; Herrmann, Megan; Mitchell, Gordon S.; Rymer, William Z.

    2014-01-01

    Objectives: To test the hypothesis that daily acute intermittent hypoxia (dAIH) and dAIH combined with overground walking improve walking speed and endurance in persons with chronic incomplete spinal cord injury (iSCI). Methods: Nineteen subjects completed the randomized, double-blind, placebo-controlled, crossover study. Participants received 15, 90-second hypoxic exposures (dAIH, fraction of inspired oxygen [Fio2] = 0.09) or daily normoxia (dSHAM, Fio2 = 0.21) at 60-second normoxic intervals on 5 consecutive days; dAIH was given alone or combined with 30 minutes of overground walking 1 hour later. Walking speed and endurance were quantified using 10-Meter and 6-Minute Walk Tests. The trial is registered at ClinicalTrials.gov (NCT01272349). Results: dAIH improved walking speed and endurance. Ten-Meter Walk time improved with dAIH vs dSHAM after 1 day (mean difference [MD] 3.8 seconds, 95% confidence interval [CI] 1.1–6.5 seconds, p = 0.006) and 2 weeks (MD 3.8 seconds, 95% CI 0.9–6.7 seconds, p = 0.010). Six-Minute Walk distance increased with combined dAIH + walking vs dSHAM + walking after 5 days (MD 94.4 m, 95% CI 17.5–171.3 m, p = 0.017) and 1-week follow-up (MD 97.0 m, 95% CI 20.1–173.9 m, p = 0.014). dAIH + walking increased walking distance more than dAIH after 1 day (MD 67.7 m, 95% CI 1.3–134.1 m, p = 0.046), 5 days (MD 107.0 m, 95% CI 40.6–173.4 m, p = 0.002), and 1-week follow-up (MD 136.0 m, 95% CI 65.3–206.6 m, p < 0.001). Conclusions: dAIH ± walking improved walking speed and distance in persons with chronic iSCI. The impact of dAIH is enhanced by combination with walking, demonstrating that combinatorial therapies may promote greater functional benefits in persons with iSCI. Classification of evidence: This study provides Class I evidence that transient hypoxia (through measured breathing treatments), along with overground walking training, improves walking speed and endurance after iSCI. PMID:24285617

  6. Utilization of the walking oximetry test to allow safe ambulation after pulmonary resection.

    PubMed

    Kageyama, Y; Urabe, N; Chiba, A

    2001-01-01

    Supplemental oxygen therapy after pulmonary resection can generally be tapered according to arterial blood gases at rest or pulse oximetry (SpO2). However, detecting exercise-induced oxygen desaturation can be difficult. We developed the walking oximetry test (WOT) so that thoracotomy patients could be rehabilitated without the risk of undetected ambulatory hypoxemia. The subjects were 58 patients who had undergone pulmonary resection and could walk at the bedside, with oxygen at 3 l/min via a nasal cannula. Patients with a value of more than 100 torr were allowed to walk with assistance for 6 min in the corridor. The oxygen flow rate was kept at 3 l/min and the walking pace was less than 50 m/min. SpO2 was determined using a wristwatch pulse oximeter. The test was stopped if the SpO2 fell below 90% or there was a score of 5 or more on the Borg scale (range 1-10). Oxygen desaturation occurred in six patients (10%) during the WOT. These patients underwent ambulatory training with sufficient oxygen supplementation and were then tested again. Patients whose SpO2 values remained higher than 90% and who showed no more than 5% desaturation were permitted to walk in the corridor with oxygen at 3 l/min via a nasal cannula. All these patients had a Borg score of 4 or lower. The WOT is a reliable, nonvasive method for detecting exercise-induced oxygen desaturation during ambulation after pulmonary resection.

  7. Six-minute walk test in children and adolescents with renal diseases: tolerance, reproducibility and comparison with healthy subjects

    PubMed Central

    Watanabe, Flávia Tieme; Koch, Vera Herminia Kalika; Juliani, Regina Celia Turola Passos; Cunha, Maristela Trevisan

    2016-01-01

    OBJECTIVES: To evaluate exercise tolerance and the reproducibility of the six-minute walk test in Brazilian children and adolescents with chronic kidney disease and to compare their functional exercise capacities with reference values for healthy children. METHODS: This cross-sectional study assessed the use of the six-minute walk test in children and adolescents aged 6-16 with stage V chronic kidney disease. For statistical analysis of exercise tolerance, including examinations of correlations and comparisons with reference values, the longest walked distances were considered. The reproducibility of the six-minute walk test was assessed using intraclass correlation coefficients. RESULTS: A total of 38 patients (14 females and 24 males) were evaluated, including 5 on peritoneal dialysis, 12 on hemodialysis and 21 who had undergone renal transplantation, with a median age of 11.2 years (6.5-16). The median walked distance was 538.5 meters (413-685) and the six-minute walk test was found to be reproducible. The walked distance was significantly correlated with age (r=0.66), weight (r=0.76), height (r=0.82), the height Z score (r=0.41), hemoglobin (r=0.46), hematocrit (r=0.47) and post-test systolic blood pressure (r=0.39). The chronic kidney disease patients predicted walked distance was 84.1% of the reference value according to age, 90.6% according to age-corrected height and 87.4% according to a predictive equation. CONCLUSIONS: The stage V chronic kidney disease patients had a significantly decreased functional exercise capacity, as measured by the six-minute walk test, compared with the healthy pediatric reference values. In addition, the six-minute walk test was shown to be well tolerated, reliable and applicable as a low-cost tool to monitor functional exercise capacity in patients with renal disease. PMID:26872080

  8. Incremental shuttle walk test: Reference values and predictive equation for healthy Indian adults

    PubMed Central

    Agarwal, Bela; Shah, Monal; Andhare, Nilesh; Mullerpatan, Rajani

    2016-01-01

    Purpose: Physical inactivity in Indians is leading to an increase in noncommunicable disorders at an early age in life. Early identification and quantification of the lack of physical activity using simple and reliable exercise testing is the need of the hour. The incremental shuttle walk test (ISWT) is an externally paced walk test widely used for the evaluation of exercise capacity. Currently the normative values available for clinical reference are generated from Western populations. Hence, the study was conducted to find normative values for the ISWT in healthy Indian adults (17-75 years). Materials and Methods: A convenience sample of 862 subjects was recruited after ethical approval was obtained. All subjects were divided into groups as per age and gender. For age, the grouping was as follows: Group 1: Young adulthood (17-40 years), group 2: Middle adulthood (40-65 years), and group 3: Old adulthood (>65 years). The ISWT was performed as per standard protocol by Sally Singh. Results: The average distance walked were 709.2m,556.4m and 441.3m in females and 807.9 m, 639.6 m and 478.2 m in males in the three respective age groups. Stepwise regression analysis revealed age and gender as key variables correlating with incremental shuttle walk distance (ISWD). The derived predictive equations for males and females may be given as follows: 740.351 - (5.676 × age) + (99.007 × gender). Conclusion: Reference values were generated for healthy Indian adults. Physiological response to the ISWT was shown to be affected by gender and increasing age. Easily measurable variables explained 68% of the variance seen in the test, making the reference equation a relevant part of the evaluation of the ISWT. PMID:26933305

  9. Reference Values for the Six-Minute Walk Test in Healthy Children and Adolescents: a Systematic Review

    PubMed Central

    Cacau, Lucas de Assis Pereira; de Santana-Filho, Valter Joviniano; Maynard, Luana G.; Gomes Neto, Mansueto; Fernandes, Marcelo; Carvalho, Vitor Oliveira

    2016-01-01

    Objective The aim of the study is to compare the available reference values and the six-minute walk test equations in healthy children/adolescents. Our systematic review was planned and performed in accordance with the PRISMA guidelines. We included all studies that established reference values for the six-minute walk test in healthy children/adolescents. Methods To perform this review, a research was performed in PubMed, EMBASE (via SCOPUS) and Cochrane (LILACS), Bibliographic Index Spanish in Health Sciences, Organization Collection Pan-American Health Organization, Publications of the World Health Organization and Scientific Electronic Library Online (SciELO) via Virtual Health Library until June 2015 without language restriction. Results The initial research identified 276 abstracts. Twelve studies met the inclusion criteria and were fully reviewed and approved by both reviewers. None of the selected studies presented sample size calculation. Most of the studies recruited children and adolescents from school. Six studies reported the use of random samples. Most studies used a corridor of 30 meters. All studies followed the American Thoracic Society guidelines to perform the six-minute walk test. The walked distance ranged 159 meters among the studies. Of the 12 included studies, 7 (58%) reported descriptive data and 6 (50%) established reference equation for the walked distance in the six-minute walk test. Conclusion The reference value for the six-minute walk test in children and adolescents ranged substantially from studies in different countries. A reference equation was not provided in all studies, but the ones available took into account well established variables in the context of exercise performance, such as height, heart rate, age and weight. Countries that did not established reference values for the six-minute walk test should be encouraged to do because it would help their clinicians and researchers have a more precise interpretation of the test

  10. Shuttle walking versus maximal cycle testing: clinical correlates in patients with kyphoscoliosis.

    PubMed

    López-Campos, José Luis; Cejudo, Pilar; Ortega, Francisco; López-Márquez, Isabel; Márquez-Martín, Eduardo; Capote, Francisco; Echevarría, Miriam; Montemayor, Teodoro; Barrot, Emilia

    2008-02-29

    A cross-sectional prospective design was used to compare the effectiveness of the shuttle walking test (SWT) and the maximal cycle ergometry test (CET) to assess the functional capacity of patients with chronic hypercapnic respiratory failure due to severe kyphoscoliosis. Twenty-four patients completed both the SWT and CET. Heart rate, blood pressure, leg fatigue, chest pain and dyspnea (Borg's scale) were measured immediately after each test. Correlation coefficients and Bland-Altman analysis were used to compare the two methods. Borg's dyspnea, leg and chest pain after exercise were not significantly different between tests. Only heart rate (SWT 130[20.7] versus CET 116[28.75]; p = 0.048) and diastolic blood pressure (SWT: 85.5[13.75] versus CET 95[17.5]; p = 0.021) were slightly but significantly different between the two protocols. There was a good positive correlation between the distance walked in SWT and maximal oxygen consumption (r = 0.675; p < 0.001). SWT and CET testing elicited similar clinical and hemodynamic responses. SWT is a feasible measure of functional capacity in this patient group.

  11. Acute Cardiorespiratory and Metabolic Responses During Exoskeleton-Assisted Walking Overground Among Persons with Chronic Spinal Cord Injury

    PubMed Central

    Hartigan, Clare; Kandilakis, Casey; Pharo, Elizabeth; Clesson, Ismari

    2015-01-01

    Background: Lower extremity robotic exoskeleton technology is being developed with the promise of affording people with spinal cord injury (SCI) the opportunity to stand and walk. The mobility benefits of exoskeleton-assisted walking can be realized immediately, however the cardiorespiratory and metabolic benefits of this technology have not been thoroughly investigated. Objective: The purpose of this pilot study was to evaluate the acute cardiorespiratory and metabolic responses associated with exoskeleton-assisted walking overground and to determine the degree to which these responses change at differing walking speeds. Methods: Five subjects (4 male, 1 female) with chronic SCI (AIS A) volunteered for the study. Expired gases were collected during maximal graded exercise testing and two, 6-minute bouts of exoskeleton-assisted walking overground. Outcome measures included peak oxygen consumption (V̇O2peak), average oxygen consumption (V̇O2avg), peak heart rate (HRpeak), walking economy, metabolic equivalent of tasks for SCI (METssci), walk speed, and walk distance. Results: Significant differences were observed between walk-1 and walk-2 for walk speed, total walk distance, V̇O2avg, and METssci. Exoskeleton-assisted walking resulted in %V̇O2peak range of 51.5% to 63.2%. The metabolic cost of exoskeleton-assisted walking ranged from 3.5 to 4.3 METssci. Conclusion: Persons with motor-complete SCI may be limited in their capacity to perform physical exercise to the extent needed to improve health and fitness. Based on preliminary data, cardiorespiratory and metabolic demands of exoskeleton-assisted walking are consistent with activities performed at a moderate intensity. PMID:26364281

  12. [Benefits of using rapid HIV testing at the PMU-FLON walk-in clinic in Lausanne].

    PubMed

    Gilgien, W; Aubert, J; Bischoff, T; Herzig, L; Perdrix, J

    2012-05-16

    Lab tests are frequently used in primary care to guide patient care. This is particularly the case when a severe disorder, or one that will affect patients' initial care, needs to be excluded rapidly. At the PMU-FLON walk-in clinic the use of HIV testing as recommended by the Swiss Office of Public Health was hampered by the delay in obtaining test results. This led us to introduce rapid HIV testing which provides results within 30 minutes. Following the first 250 tests the authors discuss the results as well as the benefits of rapid HIV testing in an urban walk-in clinic.

  13. Reliability and validity of a twelve-minute walking test for coronary heart disease patients.

    PubMed

    de Greef, Mathieu H G; Sprenger, Siska R; Elzenga, Corrie T A; Popkema, Dorien Y; Bennekers, Johan H; Niemeijer, Menco G; Middel, Berry; Mook, Gerrit A

    2005-04-01

    This study examined the reliability and validity of a 12-min. walking test for coronary heart disease patients. CHD patients (28 men, 18 women) were recruited out of 86 CHD patients of the Martini Hospital Groningen, The Netherlands. 46 CHD patients (age M=66.0 yr., SD=6.8) participated in the reliability study and 24 (age M=62.0 yr., SD=9.2) in the validity study. A test-retest analysis showed a satisfactory Bland-Altman plot and an intraclass coefficient of .98. The Pearson correlation between the score on the test and the VO2 peak was .77. This test gives a reliable and valid assessment of cardiorespiratory fitness of CHD patients.

  14. Lung function and six-minute walk test performance in individuals with sickle cell disease

    PubMed Central

    Ohara, Daniela G.; Ruas, Gualberto; Walsh, Isabel A. P.; Castro, Shamyr S.; Jamami, Mauricio

    2014-01-01

    Background Sickle Cell Disease (SCD), which is characterized by a mutation in the gene encoding beta hemoglobin, causes bodily dysfunctions such as impaired pulmonary function and reduced functional capacity. Objective To assess changes in pulmonary function and functional capacity in patients with SCD and to identify the relationships between these variables. Method We evaluated sociodemographic, anthropometric, lung function (spirometry), respiratory (manovacuometer), peripheral muscle strength (Handgrip strength - HS) and functional capacity (i.e., the six-minute walk test) parameters in 21 individuals with SCD (average age of 29±6 years). Shapiro-Wilk, paired Student's, Wilcoxon, Pearson and Spearman correlation tests were used for statistical analyses, and the significance threshold was set at p<0.05. Results A total of 47.6% of the study subjects exhibited an altered ventilation pattern, 42.8% had a restrictive ventilatory pattern (RVP) and 4.8% exhibited a mixed ventilatory pattern (MVP). The observed maximal inspiratory pressure (MIP) values were below the predicted values for women (64 cmH2O), and the maximum expiratory pressure (MEP) values, HS values and distance walked during the 6MWT were below the predicted values for both men (103 cmH2O, 39 Kgf and 447 m, respectively) and women (64 cmH2O; 27 Kgf; 405 m, respectively). Positive correlations were observed between maximum voluntary ventilation (MVV) and MEP (r=0.4; p=0.046); MVV and BMI (r=0.6; p=0.003); and between HS and MIP (r=0.7; p=0.001), MEP (r=0.6; p=0.002), MVV (r=0.5; p=0.015), distance walked in the 6MWT (r=0.4; p=0.038) and BMI (r=0.6; p=0.004). Conclusions SCD promoted changes in lung function and functional capacity, including RVPs and a reduction in the distance walked in the 6MWT when compared to the predictions. In addition, significant correlations between the variables were observed. PMID:24675916

  15. Walk on Floor Eyes Closed Test as a Measure of Postflight Ataxia

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Fisher, E. A.; Kofman, I. S.; Cerisano, J. M.; Harm, D.L.; Peters, B. T.; Bloomberg, J. J.

    2010-01-01

    INTRODUCTION: Astronauts returning from space flight universally exhibit impaired posture and locomotion. Measurement of this impairment is an evolving process. The walk on the floor line test with the eyes closed (WOFEC) provides a unique procedure for quantifying postflight ataxia. Data from a modified WOFEC were obtained as part of an ongoing NASA interdisciplinary pre- and postflight study (Functional Task Test, FTT) designed to evaluate astronaut postflight functional performance. METHODS: Seven astronauts (5 short duration with flights of 12-16 days; 2 long duration crewmembers with flights of 6 months) were tested twice before flight, on landing day (short duration only), and 1, 6, and 30 days after flight. The WOFEC consisted of walking for 10 steps (repeated twice) with the feet heel to toe in tandem, arms folded across the chest and the eyes closed. The performance metric (scored by three examiners from video) was the percentage of correct steps completed over the three trials. A step was not counted as correct if the crewmember sidestepped, opened their eyes, or paused for more than three seconds between steps. RESULTS/ CONCLUSIONS: There was a significant decrease in percentage of correct steps on landing day (short duration crew) and on first day following landing (long duration) with partial recovery the following day, and full recovery beginning on day sixth after flight. Both short and long duration fliers appeared to be unaware of foot position relative to their bodies or the floor. Postflight, deviation from a straight path was common, and the test for two crewmembers elicited motion sickness symptoms. These data clearly demonstrate the sensorimotor challenges facing crewmembers after returning from spaceflight. The WOFEC test has value providing the investigator or crew surgeon with a simple method to quantify vestibular ataxia, as well as providing instant feedback of postural ataxia without the use of complex test equipment.

  16. Estimated V(O2)max from the rockport walk test on a nonmotorized curved treadmill.

    PubMed

    Seneli, Rhiannon M; Ebersole, Kyle T; OʼConnor, Kristian M; Snyder, Ann C

    2013-12-01

    The Rockport Walk Test (RWT) is a 1-mile walk used to estimate the maximal volume of oxygen uptake (V(O2)max). The purpose of this study was to validate the RWT on a nonmotorized curved treadmill (CT). Twenty-three healthy adults (10 females; 19-44 years old) participated. One trial of the RWT was performed on a measured indoor track (RWTO) and another on the CT (RWTC) on different days in randomized order. Heart rate (HR) and completion time were used to calculate V(O2)max using 6 different general and gender specific equations from previous research. Subjects also performed a treadmill graded exercise test (GXT), which was used as the criterion measure for V(O2)max. Completion times and HR between the 2 RWT were compared using dependent t-tests. Estimated V(O2)max values were compared between the RWTC, RWTO, and GXT through repeated measures analysis of variance, Pearson's correlations (r), and Bland-Altman's plots. There was no difference between completion times for the RWTO and RWTC but HRs were significantly higher with RWTC. When the same equation was applied to the RWTO and RWTC, there were no similar results. All V(O2)max estimations were different from observed V(O2)max except for the estimation from the relative general Kline et al. equation on the RWTO. Despite high correlations (r = 0.75-0.91), the RWTC underestimated V(O2)max. The RWTC underestimates V(O2)max but may be beneficial if a new equation were created specifically for the CT. With appropriate equations for the CT, the RWTC would provide an alternate form of V(O2)max testing.

  17. Dynamometer-based measure of spasticity confirms limited association between plantarflexor spasticity and walking function in persons with multiple sclerosis.

    PubMed

    Kremer, Theodore R; Van Dillen, Linda R; Wagner, Joanne M

    2014-01-01

    The literature shows inconsistent evidence regarding the association between clinically assessed plantar-flexor (PF) spasticity and walking function in ambulatory persons with multiple sclerosis (pwMS). The use of a dynamometer-based spasticity measure (DSM) may help to clarify this association. Our cohort included 42 pwMS (27 female, 15 male; age: 42.9 +/- 10.1 yr) with mild clinical disability (Expanded Disability Status Scale score: 3.6 +/- 1.6). PF spasticity was assessed using a clinical measure, the modified Ashworth Scale (MAS), and an instrumented measure, the DSM. Walking function was assessed by the timed 25-foot walk test (T25FWT), the 6-minute walk test (6MWT), and the 12-item Multiple Sclerosis Walking Scale (MSWS-12). Spearman rho correlations were used to evaluate relationships between spasticity measures, measures of walking speed and endurance, and self-perceived limitations in walking. The correlation was small between PF spasticity and the T25FWT (PF maximum [Max] MAS rho = 0.27, PF Max DSM rho = 0.26), the 6MWT (PF Max MAS rho = -0.20, PF Max DSM rho = -0.21), and the MSWS-12 (PF Max MAS rho = 0.11, PF Max DSM rho = 0.26). Our results are similar to reports in other neurologic clinical populations, wherein spasticity has a limited association with walking dysfunction.

  18. Six minute walk test: a simple and useful test to evaluate functional capacity in patients with heart failure.

    PubMed

    Rostagno, Carlo; Gensini, Gian Franco

    2008-09-01

    In heart failure survival is closely related to functional capacity. Peak O2 consumption at cardiopulmonary exercise test (CPET) is considered the gold standard for the evaluation of exercise tolerance. Since >70% of patients with heart failure, usually elderly or with significant comorbidities, are referred to Departments of Internal Medicine where facilities for cardiopulmonary test are rarely available, CPET may be performed in <5% of the patients. Six-minute walk test (6MWT) has been proposed as a simple, inexpensive, reproducible alternative to CPET. The 6MWT reproduces the activity of daily life and this is particularly relevant in elderly patients who usually develop symptoms below their theoretical maximal exercise capacity. Despite some limits 6MWT is attractive for patients referred to Departments of Internal Medicine allowing an objective evaluation of exercise tolerance, a better prognostic evaluation and a guide to evaluate response to medical treatment.

  19. Note: Network random walk model of two-state protein folding: Test of the theory

    NASA Astrophysics Data System (ADS)

    Berezhkovskii, Alexander M.; Murphy, Ronan D.; Buchete, Nicolae-Viorel

    2013-01-01

    We study two-state protein folding in the framework of a toy model of protein dynamics. This model has an important advantage: it allows for an analytical solution for the sum of folding and unfolding rate constants [A. M. Berezhkovskii, F. Tofoleanu, and N.-V. Buchete, J. Chem. Theory Comput. 7, 2370 (2011), 10.1021/ct200281d] and hence for the reactive flux at equilibrium. We use the model to test the Kramers-type formula for the reactive flux, which was derived assuming that the protein dynamics is described by a Markov random walk on a network of complex connectivity [A. Berezhkovskii, G. Hummer, and A. Szabo, J. Chem. Phys. 130, 205102 (2009), 10.1063/1.3139063]. It is shown that the Kramers-type formula leads to the same result for the reactive flux as the sum of the rate constants.

  20. Field Test: Results of Tandem Walk Performance Following Long-Duration Spaceflight

    NASA Technical Reports Server (NTRS)

    Rosenberg, M. J. F.; Reschke, M. F.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.; Gadd, N. E.; May-Phillips, T. R.; Lee, S. M. C.; Laurie, S. S.; Stenger, M. B.; Bloomberg, J. J.; Mulavara, A.; Kozlovskaya, I.; Tomilovskaya, E.

    2016-01-01

    BACKGROUND: Coordinated locomotion has proven to be challenging for many astronauts following long duration spaceflight. As NASA's vision for spaceflight points toward interplanetary travel, we must prepare for unassisted landings, where crewmembers may need to perform mission critical tasks within minutes of landing. Thus, it is vital to develop a knowledge base from which operational guidelines can be written that define when astronauts can be expected to safely perform certain tasks. Data obtained during the Field Test experiment (FT) will add important insight to this knowledge base. Specifically, we aim to develop a recovery timeline of functional sensorimotor performance during the first 24 hours and several days after landing. METHODS: FT is an ongoing study of 30 long-duration ISS crewmembers. Thus far, 9 have completed the full FT (5 U.S. Orbital Segment [USOS] astronauts and 4 Russian cosmonauts) and 4 more consented and launching within the next year. This is in addition to the eighteen crewmembers that participated in the pilot FT (11 USOS and 7 Russian crewmembers). The FT is conducted three times preflight and three times during the first 24 hours after landing. All crewmembers were tested in Kazakhstan in either the medical tent at the Soyuz landing site (one hour post-landing), or at the airport (four hours post-landing). The USOS crewmembers were also tested at the refueling stop (12 hours post-landing) and at the NASA Johnson Space Center (24 hours post-landing) and a final session 7 days post-landing. Crewmembers are instrumented with 9 inertial measurement unit sensors that measure acceleration and angular displacement (APDM's Emerald Sensors) and foot pressure-sensing insoles that measure force, acceleration, and center of pressure (Moticon GmbH, Munich, Germany) along with heart rate and blood pressure recording instrumentation. The FT consists of 12 tasks, but here we will focus on the most challenging task, the Tandem Walk, which was also

  1. 76 FR 21579 - Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In Freezers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-15

    ... building's heating, ventilation, and air conditioning (HVAC) system. (NRDC, No. 0064.1 at p. 8) A comment... refrigeration systems. These test procedures will be mandatory for product testing to demonstrate compliance...,'' ``Envelope,'' ``K- factor,'' ``Panel,'' ``Refrigerated,'' ``Refrigeration system,'' ``U-...

  2. Pilot Field Test: The Ability to Ambulate Following Landing as Assessed with Seat Egress, Walk and Obstacle Testing

    NASA Technical Reports Server (NTRS)

    Fisher, E. A.; Fomina, E. V; Reschke, M. F.; Cerisano, J. M.; Kofman, I. S.; Gadd, N. E.; Phillips, T. R.; Lee, S. M. C.; Laurie, S. S.; Stenger, M. B.; Bloomberg, J. J.; Mulavara, A. P.; Kozlovskaya, I. B.; Tomilovskaya, E. S.

    2016-01-01

    To date, changes in functional performance have been systematically studied after short-duration space flight. As important as the postflight functional changes have been, full functional recovery has never been investigated or established for long-duration flights. The Pilot Field Test (PFT) experiment, conducted with participation of ISS crewmembers traveling on Soyuz expeditions 34S - 41S, is comprised of several tasks designed to study the recovery of sensorimotor abilities of astronauts during the first 24 hours after landing and beyond. The objective of the Seat Egress - Walk and Obstacle Test, developed by NASA's Russian collaborators at the Institute for Biomedical Problems, is to address this gap in knowledge. This will allow us to characterize the ability of crewmembers to perform critical mission requirements that they will be expected to perform after an unassisted landing following 6 to 12 months in microgravity.

  3. Oxygen desaturation in healthy subjects undergoing the incremental shuttle walk test*

    PubMed Central

    Seixas, Daniel Machado; Seixas, Daniela Miti Tsukumo; Pereira, Monica Corso; Moreira, Marcos Mello; Paschoal, Ilma Aparecida

    2013-01-01

    OBJECTIVE: To determine the probability of oxygen desaturation in healthy individuals undergoing the incremental shuttle walk test (ISWT). METHODS: We enrolled 83 healthy subjects: 55 males (including 1 smoker) and 28 females. We determined pre-ISWT FEV1, FEV6, HR and SpO2, as well as post-ISWT HR and SpO2. RESULTS: Mean values overall were as follows: age, 35.05 ± 12.53 years; body mass index, 24.30 ± 3.47 kg/m2; resting HR, 75.12 ± 12.48 bpm; resting SpO2, 97.96 ± 1.02%; FEV1, 3.75 ± 0.81 L; FEV6, 4.45 ± 0.87 L; FEV1/FEV6 ratio, 0.83 ± 0.08 (no restriction or obstruction); incremental shuttle walk distance, 958.30 ± 146.32 m; post-ISWT HR, 162.41 ± 18.24 bpm; and post-ISWT SpO2, 96.27 ± 2.21%. In 11 subjects, post-ISWT SpO2 was higher than was pre-ISWT SpO2. In 17 subjects, there was a 4% decrease in SpO2 after the ISWT. There were no statistically significant differences between the groups with and without post-ISWT oxygen desaturation in terms of age, gender, FEV1, FEV6, FEV1/FEV6, pre-ISWT SpO2, incremental shuttle walk distance, HR, or percentage of maximal HR. In the individuals with post-ISWT oxygen desaturation, the body mass index was higher (p = 0.01) and post-ISWT SpO2 was lower (p = 0.0001). CONCLUSIONS: Healthy individuals can present oxygen desaturation after the ISWT. Using the ISWT to predict subtle respiratory abnormalities can be misleading. In healthy subjects, oxygen desaturation is common after the ISWT, as it is during any intense physical activity. PMID:24068265

  4. The J-Meter Coercivity Spectrometer - Hysteresis Loop, IRM Acquisition Spectrum and Viscosity Spectrum in 6 Minutes

    NASA Astrophysics Data System (ADS)

    Enkin, R. J.; Nourgaliev, D.; Iassonov, P.

    2009-05-01

    The J-Meter Coercivity Spectrometer uses an innovative robust design for measuring a geological sample's magnetic hysteresis loop, IRM acquisition spectrum and viscosity spectrum in 6 minutes. With this tool, several labs around the world have been able measure large sample collections and develop useful magnetic proxies for a variety of paleoclimate, diagenesis and other studies. The main element of the J-meter is a pulse magnetometer, in which an electromotive force pulse is induced in an array of pick-up coils by the magnetic field of a sample moving at a high speed past the coils. The sample is placed near the rim of a 50 cm diameter plexiglas disk which rotates 18 times a second through the pole pieces of an electromagnet. Both the induced and remanent magnetization are measured during each rotation of the disk. Induced magnetization for hysteresis loops are measure with a set of pick-up coils mounted directly on the pole pieces, similar to the geometry used for a vibrating sample magnetometer. The magnetic remanence is measured with a second array of coils situated away from the electromagnet and surrounded by a three-layer mu-metal shield. The electromagnet field is ramped up to 500 mT, and the down to the opposite polarity (-500 mT). The J meter is called a coercivity spectrometer because it is particularly well suited to measuring the IRM acquisition curve with sufficient sensitivity and resolution to take the derivative which defines the coercivity spectrum. To finish each measurement, the magnetic field is cut to zero and the viscous demagnetization is monitored for 100s, mostly following a log(time) relationship but with perturbations determined by the grain size distribution of the finest grains. A suite of analysis programs have been developed to determine hysteresis parameters and S-ratios, and to characterize coercivity and viscosity spectra. We present a series of applications demonstrating the power of the J-Meter to trace sediment sources

  5. Short-distance walking speed and timed walking distance: redundant measures for clinical trials?

    PubMed

    Dobkin, Bruce H

    2006-02-28

    The velocity of a 15-meter walk and walking endurance (distance covered in 6 minutes) are considered distinct outcomes in clinical trials of stroke rehabilitation. Comfortable velocities used for each task in 24 subjects with chronic hemiparesis were not significantly different, however. Although speed and endurance did not reflect different domains of efficacy in outpatients whose usual speed was >0.5 m/s, the fastest feasible 15-meter velocity augmented these measures.

  6. Increasing walking among older people: A test of behaviour change techniques using factorial randomised N-of-1 trials

    PubMed Central

    Nyman, Samuel R.; Goodwin, Kelly; Kwasnicka, Dominika; Callaway, Andrew

    2016-01-01

    Objective: Evaluations of techniques to promote physical activity usually adopt a randomised controlled trial (RCT). Such designs inform how a technique performs on average but cannot be used for treatment of individuals. Our objective was to conduct the first N-of-1 RCTs of behaviour change techniques with older people and test the effectiveness of the techniques for increasing walking within individuals. Design: Eight adults aged 60–87 were randomised to a 2 (goal-setting vs. active control) × 2 (self-monitoring vs. active control) factorial RCT over 62 days. The time series data were analysed for each single case using linear regressions. Main outcome measures: Walking was objectively measured using pedometers. Results: Compared to control days, goal-setting increased walking in 4 out of 8 individuals and self-monitoring increased walking in 7 out of 8 individuals. While the probability for self-monitoring to be effective in 7 out of 8 participants was beyond chance (p = .03), no intervention effect was significant for individual participants. Two participants had a significant but small linear decrease in walking over time. Conclusion: We demonstrate the utility of N-of-1 trials for advancing scientific enquiry of behaviour change and in practice for increasing older people’s physical activity. PMID:26387689

  7. Six-Minute Walk Test as a Predictor for Outcome in Children with Dilated Cardiomyopathy and Chronic Stable Heart Failure.

    PubMed

    den Boer, Susanna L; Flipse, Daniël H K; van der Meulen, Marijke H; Backx, Ad P C M; du Marchie Sarvaas, Gideon J; Ten Harkel, Arend D J; van Iperen, Gabriëlle G; Rammeloo, Lukas A J; Tanke, Ronald B; Helbing, Willem A; Takken, Tim; Dalinghaus, Michiel

    2017-03-01

    Cardiopulmonary exercise testing is an important tool to predict prognosis in children and adults with heart failure. A much less sophisticated exercise test is the 6 min walk test, which has been shown an independent predictor for morbidity and mortality in adults with heart failure. Therefore, we hypothesized that the 6 min walk test could be predictive for outcome in children with dilated cardiomyopathy. We prospectively included 49 children with dilated cardiomyopathy ≥6 years who performed a 6 min walk test. Median age was 11.9 years (interquartile range [IQR] 7.4-15.1), median time after diagnosis was 3.6 years (IQR 0.6-7.4). The 6 min walk distance was transformed to a percentage of predicted, using age- and gender-specific norm values (6MWD%). For all patients, mean 6MWD% was 70 ± 21%. Median follow-up was 33 months (IQR 14-50). Ten patients reached the combined endpoint of death or heart transplantation. Using univariable Cox regression, a higher 6MWD% resulted in a lower risk of death or transplantation (hazard ratio 0.95 per percentage increase, p = 0.006). A receiver operating characteristic curve was generated to define the optimal threshold to identify patients at highest risk for an endpoint. Patients with a 6MWD% < 63% had a 2 year transplant-free survival of 73%, in contrast to a transplant-free survival of 92% in patients with a 6MWD% ≥ 63% (p = 0.003). In children with dilated cardiomyopathy, the 6 min walk test is a simple and feasible tool to identify children with a higher risk of death or heart transplantation.

  8. Convergent validity of the Timed Up and Go Test and Ten-metre Timed Walk Test in pregnant women with pelvic girdle pain.

    PubMed

    Evensen, Natalie Michelle; Kvåle, Alice; Brækken, Ingeborg Hoff

    2016-02-01

    Pregnant women with pelvic girdle pain (PGP) often experience functional difficulties, in particular walking difficulties. Currently, however, there is a lack of validated performance-orientated outcome measures available for use in this population. The Timed Up and Go (TUG) test and Ten-metre Timed Walk Test (10 mTWT) are two short-distance walking tests that have demonstrated reliability in pregnant women with PGP, but as yet have no established validity. The aim of the present study was to evaluate the convergent validity of the TUG and 10 mTWT by comparing performances on these two walking tests with scores achieved on the Active Straight Leg Raise (ASLR) test and the Pelvic Girdle Questionnaire (PGQ). Eighteen pregnant women with PGP aged 31.4 years (SD = 2.7) and 28.9 weeks pregnant (SD = 7.3) were included. Spearman rank correlation coefficient (rs) was used to determine convergent validity. Strong correlations were found between the TUG and ASLR (rs = 0.73, p = 0.001), and the 10 mTWT and ASLR (rs = -0.65, p = 0.003). Relationships between the TUG and PGQ were moderate (rs = 0.41 to 0.52) and between the 10 mTWT and PGQ low to moderate (rs = -0.25 to -0.56). The strong relationships between the walking tests and the ASLR may suggest these tests all assess the same construct. The weaker relationships found between the walking tests and the PGQ may be related to the self-report and multiple functional activities nature of the questionnaire. This study found both the TUG and 10 mTWT to be valid weight-bearing physical performance measures, although more research is warranted due to the small study sample.

  9. 75 FR 186 - Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In Freezers

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-04

    ... free-standing structure, testing it as a whole building would not be practical. (Kason, No. 16 at pp. 1... calculation methodology or software program as an AEDM could be problematic. Owens Corning questioned whether... software as an AEDM could be unfair to manufacturers with fewer resources, because the software...

  10. Does the incremental shuttle walk test require maximal effort in young obese women?

    PubMed

    Jürgensen, S P; Trimer, R; Di Thommazo-Luporini, L; Dourado, V Z; Bonjorno-Junior, J C; Oliveira, C R; Arena, R; Borghi-Silva, A

    2016-07-11

    Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI ≥30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 - age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option.

  11. Measuring Steady-State Oxygen Uptake during the 6-Min Walk Test in Adults with Cerebral Palsy: Feasibility and Construct Validity

    ERIC Educational Resources Information Center

    Maltais, Desiree B.; Robitaille, Nancy-Michelle; Dumas, Francine; Boucher, Normand; Richards, Carol L.

    2012-01-01

    This study evaluated the feasibility of measuring steady-state oxygen uptake (V[Combining Dot Above]O[subscript 2]) during the 6-min walk test (6MWT) in adults with cerebral palsy (CP) who walk without support and whether there is construct validity for net 6MWT V[Combining Dot Above]O[subscript 2] as a measure of their walking ability.…

  12. Oxygen desaturation during the six-minute walk test in COPD patients*

    PubMed Central

    Moreira, Maria Ângela Fontoura; de Medeiros, Gabriel Arriola; Boeno, Francesco Pinto; Sanches, Paulo Roberto Stefani; da Silva, Danton Pereira; Müller, André Frotta

    2014-01-01

    Objective: To evaluate the behavior of oxygen saturation curves throughout the six-minute walk test (6MWT) in patients with COPD. Methods: We included 85 patients, all of whom underwent spirometry and were classified as having moderate COPD (modCOPD, n = 30) or severe COPD (sevCOPD, n = 55). All of the patients performed a 6MWT, in a 27-m corridor with continuous SpO2 and HR monitoring by telemetry. We studied the SpO2 curves in order to determine the time to a 4% decrease in SpO2, the time to the minimum SpO2 (Tmin), and the post-6MWT time to return to the initial SpO2, the last designated recovery time (RT). For each of those curves, we calculated the slope. Results: The mean age in the modCOPD and sevCOPD groups was 66 ± 10 years and 62 ± 11 years, respectively. At baseline, SpO2 was > 94% in all of the patients; none received supplemental oxygen during the 6MWT; and none of the tests were interrupted. The six-minute walk distance did not differ significantly between the groups. The SpO2 values were lowest in the sevCOPD group. There was no difference between the groups regarding RT. In 71% and 63% of the sevCOPD and modCOPD group patients, respectively, a ≥ 4% decrease in SpO2 occurred within the first minute. We found that FEV1% correlated significantly with the ΔSpO2 (r = −0.398; p < 0.001), Tmin (r = −0.449; p < 0.001), and minimum SpO2 (r = 0.356; p < 0.005). Conclusions: In the sevCOPD group, in comparison with the modCOPD group, SpO2 was lower and the Tmin was greater, suggesting a worse prognosis in the former. PMID:25029644

  13. Responsiveness of the ten-metre walk test, Step Test and Motor Assessment Scale in inpatient care after stroke

    PubMed Central

    2014-01-01

    Background Responsiveness of a measurement tool is its ability to detect change over time. The aim of this study was to determine the responsiveness and floor/ceiling effects of the ten-metre walk test (10mWT), Step Test and Motor Assessment Scale (MAS) lower limb items. Methods An inception cohort study was conducted, including 190 stroke survivors admitted to a comprehensive stroke unit. The 10mWT, Step Test and MAS were administered within 48 hours of admission and repeated in the 48 hours before discharge. Responsiveness was analysed with Effect Size (ES), Standardised Response Mean (SRM) and a median-based Effect Size (mES). Floor/ceiling effects were calculated as the percentage of participants scoring the lowest/highest possible scores. Results Responsiveness of each outcome measure varied according to the statistic used. Values for the 10mWT were ES 1.44, SRM 0.93, mES 0.45; the step test ES 1.99, SRM 0.88, mES 0.36; MAS sit-to-stand (item 4) score ES 1.27, SRM 1.00, mES 0.50; and for MAS item 5 (walking) ES 1.43, SRM 1.10, mES 0.50. The MAS item 3 (sitting balance) was moderately responsive in all analyses (ES 0.72, SRM 0.71, mES 0.50). The MAS mobility score (summed items 3-5) consistently showed large responsiveness (ES 1.42, SRM 1.16, mES 0.92). The Step Test had the highest proportion of participants who didn’t change (46%) and item 4 of the MAS showed the largest ceiling effect on discharge (44%). Conclusions Most measures were able to detect change in motor performance during inpatient stroke rehabilitation but the MAS mobility score was the only measure that demonstrated large responsiveness and no marked floor or ceiling effects. PMID:24934859

  14. Protocol Variations and Six-Minute Walk Test Performance in Stroke Survivors: A Systematic Review with Meta-Analysis

    PubMed Central

    Dunn, A.; Marsden, D. L.; Nugent, E.; Van Vliet, P.; Spratt, N. J.; Attia, J.; Callister, R.

    2015-01-01

    Objective. To investigate the use of the six-minute walk test (6MWT) for stroke survivors, including adherence to 6MWT protocol guidelines and distances achieved. Methods. A systematic search was conducted from inception to March 2014. Included studies reported a baseline (intervention studies) or first instance (observational studies) measure for the 6MWT performed by stroke survivors regardless of time after stroke.  Results. Of 127 studies (participants n = 6,012) that met the inclusion criteria, 64 were also suitable for meta-analysis. Only 25 studies made reference to the American Thoracic Society (ATS) standards for the 6MWT, and 28 reported using the protocol standard 30 m walkway. Thirty-nine studies modified the protocol walkway, while 60 studies did not specify the walkway used. On average, stroke survivors walked 284 ± 107 m during the 6MWT, which is substantially less than healthy age-matched individuals. The meta-analysis identified that changes to the ATS protocol walkway are associated with reductions in walking distances achieved. Conclusion. The 6MWT is now widely used in stroke studies. The distances achieved by stroke patients indicate substantially compromised walking ability. Variations to the standard 30 m walkway for the 6MWT are common and caution should be used when comparing the values achieved from studies using different walkway lengths. PMID:25685596

  15. Factors Shaping the Decision of College Students to Walk or Drive under the Influence of Alcohol: A Test of Rational Choice Theory

    ERIC Educational Resources Information Center

    Mason, Ashley; Monk-Turner, Elizabeth

    2010-01-01

    Aims: Rational Choice theory was tested to better understand the differences in behaviour regarding walking and driving under the influence of alcohol. Methods: Students at a residential college campus in Virginia were surveyed. Findings: Results show that students were less likely to walk or drive while intoxicated if they believed such behaviour…

  16. The Use of the 6-Min Walk Test as a Proxy for the Assessment of Energy Expenditure during Gait in Individuals with Lower-Limb Amputation

    ERIC Educational Resources Information Center

    Kark, Laurena; McIntosh, Andrew S.B; Simmons, Annea

    2011-01-01

    The objective of this study was to determine, and compare, the utility of the 6-min walk test (6 MWT) and self-selected walking speed over 15 m as proxies for the assessment of energy expenditure during gait in individuals with lower-limb amputation. Patients with unilateral, transfemoral amputation (n = 6) and patients with unilateral,…

  17. Relationship between perceived and measured changes in walking after stroke

    PubMed Central

    Tang, Ada; Eng, Janice; Rand, Debbie

    2012-01-01

    Background and Purpose Examining participant-perceived change in walking provides insight into whether changes were meaningful for participants. This study examined the relationships between change scores in standardized walking outcomes and ratings of perceived change following exercise post-stroke. Methods Self- and fast-paced gait speed and 6-Minute Walk Test (6MWT) distance were assessed in 22 participants (age 67±10.3 years, 1.8±0.9 years post-stroke) before and after a 3-month exercise program. Perceived changes were evaluated using a 15-point Likert scale. Correlation analyses between measured and perceived change were performed. Subgroups of low and high baseline scores were compared for differences in measured and perceived change. Results 6MWT change was correlated with perceived change (ρ=0.52, P=0.01), greater change was demonstrated among participants who perceived improvement relative to those who did not (difference 34.4 meters (95% CI 17.2, 51.6), P=0.04). After controlling for measured change, participants with low baseline 6MWT distances perceived less change compared to those who walked high distances at baseline (P=0.006). Discussion and Conclusions A global rating scale using meaningful and context-specific questions was used to determine the relationship between measured and participant-perceived change in 6MWT distance. A meaningful difference in 6MWT change was observed between participants who did and those who did not perceive improvement. Individuals with lower baseline scores may require larger changes in walking distance to perceive that a change has occurred. This study contributes to a growing body of evidence about the relationships between perceived and measured change in function, and is a step in determining thresholds for perceived change in walking after stroke. PMID:22850336

  18. Six-Minute Walk Test in Evaluation of Children with Pulmonary Arterial Hypertension.

    PubMed

    Zuk, Malgorzata; Migdal, Anna; Jagiellowicz-Kowalska, Dorota; Mazurkiewicz, Katarzyna; Sadel-Wieczorek, Anna; Brzezinska-Rajszys, Grazyna

    2017-04-01

    Six-minute walk test (6MWT) is a submaximal exercise test applied for evaluation of adults with pulmonary arterial hypertension (PAH). It was widely used as an endpoint in the clinical trials. The aim of the study was to assess the usefulness of 6MWT in management of children with PAH and to establish correlations with other clinical features. 164 6MWT were performed in 15 children between 5 and 18 years with PAH confirmed by right heart catheterization (102 in patients with shunt, 62 without shunt). Distance in 6MWT (6MWD)-% of predicted for age and gender, desaturation at the maximum effort, peak heart rate (HR)-% of maximal HR, were compared to the level of NTproBNP, WHO-FC, echocardiography parameters, and events of PAH treatment intensification. 6MWD had low negative correlation with peak HR (τ -0.1 p = 0,03), negative correlation with NTproBNP (τ -0.17 p = 0.002), and no dependence on echocardiography parameters. The presence of shunt was associated with lower 6MWD, lower blood saturation at rest, and higher desaturation after effort. Patients in III/IV WHO-FC achieved higher rest HR and maximal HR in comparison to patients in I/II WHO-FC (63.1 vs. 55.2% p < 0.01) and lower 6MWD (64.3 vs. 77.5% p < 0.01). In 14 out of 20 6MWT performed after treatment intensification, increase of distance was observed. The results of 6MWT were consistent with clinical status (WHO-FC, NTproBNP) but not with echocardiography parameters. 6MWT may be the source of additional information in management of children with PAH.

  19. Does the incremental shuttle walk test require maximal effort in young obese women?

    PubMed Central

    Jürgensen, S.P.; Trimer, R.; Di Thommazo-Luporini, L.; Dourado, V.Z.; Bonjorno-Junior, J.C.; Oliveira, C.R.; Arena, R.; Borghi-Silva, A.

    2016-01-01

    Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI ≥30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 – age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option. PMID:27409333

  20. Assessments of Motor Abnormalities on the Grid-Walking and Foot-Fault Tests From Undernutrition in Wistar Rats.

    PubMed

    Horiquini Barbosa, Everton; Vallim, José Henrique; Lachat, João-José; de Castro, Vera Lucia S S

    2016-01-01

    This study was designed to verify whether different lactation conditions influenced nervous system development. The authors used motor tasks to verify changes in exploratory activity and muscle strength of weaned rats from different litter sizes and evaluated the applicability of the grid-walking test for assessing motor abnormalities caused by undernutrition. Alterations in litter size during the suckling period perturbed the nutritional status of pups, which exhibited body weight differences between the groups. Large-litter (L) pups showed significant delays in achieving developmental milestones and neurological reflexes compared to the small-litter (S) and medium-litter (M) pups. The S, M, and L group pups exhibited similar exploratory responses and muscle strength. In the grid-walking and foot-fault tests, the L group pups traveled shorter distances and, consequently, had less footsteps. However, the percentages of foot faults in the L group were higher than S and M groups. These results reflect delayed maturation of structures responsible for sensorimotor responses, such as the cerebellum, because much cerebellar maturation takes place postnatally. This is the first study to report that early undernutrition in pups resulted in suboptimal performances on the grid-walking and foot-fault tests and that the former test was sensitive to alterations caused by nutritional deficiency.

  1. Heart rate recovery after the 10-m incremental shuttle walking test in older adults with intellectual disabilities.

    PubMed

    Oppewal, Alyt; Hilgenkamp, Thessa I M; van Wijck, Ruud; Evenhuis, Heleen M

    2014-03-01

    Heart rate recovery (HRR) after exercise is an independent predictor for cardiovascular and all-cause mortality. To investigate the usefulness of HRR in cardiorespiratory exercise testing in older adults with intellectual disabilities (ID), the aims of this study were (a) to assess HRR in older adults with ID after the 10-m incremental shuttle walking test (ISWT) and (b) its association with personal characteristics (gender, age, distance walked on the ISWT, level of ID, genetic syndrome causing ID, autism, behavioral problems, and peak heart rate (HRpeak)). HRR was assessed after the 10-m incremental shuttle walking test in 300 older adults (>50 years) with borderline to profound ID. HRR was defined as the change from HRpeak during the ISWT to heart rate measured after 1, 2, 3, 4, and 5 min of passive recovery. The largest decrease in heart rate was in the first minute of recovery leveling off toward the fifth minute of recovery. An abnormal HHR (≤12 bpm) was seen in 36.1% of the participants with Down syndrome (DS) and in 30.7% of the participants with ID by other causes. After the fifth minute the heart rates of 69.4% of the participants with DS and of 61.4% of the participants with ID by other causes returned to resting levels. HRpeak and distance walked on the ISWT were positively related to all HRR measures. More severe ID was negatively related and having DS positively related to HRR after 3-5 min of recovery. The other characteristics were not significantly associated to HRR. HRR is a potentially useful outcome measure in cardiorespiratory fitness testing of older adults with ID with a direct, objective, and non-invasive measurement. Further research is needed to identify the relation between HRR and adverse health outcomes in this population.

  2. Functional outcome assessment of lower limb amputees and prosthetic users with a 2-minute walk test.

    PubMed

    Frlan-Vrgoc, Ljubinka; Vrbanić, Tea Schnurrer-Luke; Kraguljac, Darko; Kovacević, Miljenko

    2011-12-01

    The aim of this study was to assess the functional outcome of a population of lower limb amputees supplied with prosthesis. The research was conducted from June to September of 2010 at the Center for Physical and Rehabilitation Medicine, of the Clinical Hospital Center Rijeka, Croatia. The study included 50 adult subjects of both genders with a unilateral transtibial or transfemoral lower limb amputations. The 2-minute walk test (2MWT) was used to assess the functional outcome of these individuals. Data were statistically analyzed. Subjects were divided into groups according to age. The best results were obtained by subjects between the age of 45 and 59 years. The difference between groups was statistically significant (p < 0.001). Taking into account the cause of amputation, there was a statistically significant difference in the results of the 2 MWT between subjects in whom the cause of amputation was circulatory and those where the cause of the amputation was not due to circulatory problems. The best results were obtained in subjects in whom the cause of amputation was not circulatory (p = 0.009). Considering the level of amputation there was a statistically significant difference in the results of the 2MWT between subjects with transtibial and those with transfemoral amputations. Better results were obtained in transtibial amputees (p = 0.039). Considering the first prosthetic supply, better results were obtained in subjects using prosthetic devices over 9 years (p = 0.031). Our research confirmed that age, gender, level and cause of amputation, including the time from the first prosthetic supply have an effect on the 2MWT results.

  3. The development and examination of a new walking executive function test for people over 50years of age.

    PubMed

    Leyva, Arturo; Balachandran, Anoop; Britton, Jennifer C; Eltoukhy, Moataz; Kuenze, Christopher; Myers, Nicholas D; Signorile, Joseph F

    2017-03-15

    A reduction in executive function (EF) performance is a major factor associated with the loss of functional independence among older adults. Computer-based tests are commonly used to evaluate EF; however, these mouse or keyboard tests are upper limb dominant while most activities of daily living (ADL, e.g. crossing a street) are lower limb dominant. The purpose of this study was to examine the utility of a newly developed walking EF test called the Walking Response and Inhibition Test (WRIT). The WRIT was validated by comparing its results a number of established computer-based tests and to an ADL-related test known to require EF, the Timed "Up & Go" Test (TUG). Fifty healthy adults, ranging in age from 50 to 86years (mean±SD, 65.5±9.6y) were evaluated using the WRIT, three computer-based EF tests, the TUG, a verbal memory test and an agility test. All computer-based EF tests were positively correlated to the WRIT (p<0.05); however, regression analyses revealed that the WRIT explained 37.5% of the variance in the TUG, while a composite of traditional computer-based tests explained 10.5%. As indicated by Lin's Concordance reliability (pc=0.82) between testing days was high and was supported by a Cronbach's alpha of 0.90. Bland-Altman analyses also demonstrated good agreement between the testing days with a small mean difference 3.48 (-3.71, 10.67). These results support the validity and reliability of the WRIT, and indicate that when assessing EF as it relates to functionality, the WRIT test may be a more appropriate measure than existing computer-based mouse and keyboard tests.

  4. Is one trial enough for repeated testing? Same-day assessments of walking, mobility and fine hand use in people with myotonic dystrophy type 1.

    PubMed

    Kierkegaard, Marie; Petitclerc, Emilie; Hébert, Luc J; Gagnon, Cynthia

    2017-02-01

    Performance-based assessments of physical function are essential in people with myotonic dystrophy type 1 (DM1) to monitor disease progression and evaluate interventions. Commonly used are the six-minute walk test, the 10 m-walk test, the timed up-and-go test, the timed-stands test, grip strength tests and the nine-hole peg test. The number of trials needed on a same-day test occasion and whether the first, best or average of trials should be reported as result is unknown. Thus, the aim was to describe and explore differences between trials in these measures of walking, mobility and fine hand use in 70 adults with DM1. Three trials were performed for each test except for the six-minute walk test where two trials were allowed. There were statistical significant differences over trials in all tests except for the 10 m-walk test and grip strength tests. Pair-wise comparisons showed that the second and third trials were in general better than the first, although effect sizes were small. At which trial the individuals performed their best differed between individuals and tests. People with severe muscular impairment had difficulties to perform repeated trials. Intraclass correlation coefficients were all high in analyses exploring how to report results. The conclusion and clinical implication is that, for a same-day test occasion, one trial is sufficient for the 10 m-walk test and grip strength tests, and that repeated trials should be allowed in the timed up-and-go test, timed-stands test and nine-hole peg tests. We recommend that two trials are performed for these latter tests as such a protocol could accommodate people with various levels of impairments and physical limitations.

  5. Diffusion tensor imaging of the corticospinal tract and walking performance in multiple sclerosis.

    PubMed

    Hubbard, Elizabeth A; Wetter, Nathan C; Sutton, Bradley P; Pilutti, Lara A; Motl, Robert W

    2016-04-15

    Research has identified a significant relationship between DTI (Diffusion Tensor Imaging) indices in the Corticospinal Tract (CST) and disability status in persons with multiple sclerosis (MS). To date, there is little known about the association between DTI indices of the CST with walking and gait outcomes in MS. This study examined the associations among DTI indices [fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD)] of the CST with walking and gait outcomes in persons with MS. We enrolled 69 persons with MS who underwent 3T brain magnetic resonance imaging (MRI) and examined white matter structural integrity in the CST in the brain with DTI. Participants completed three walking performance assessments: 6-minute walk (6MW), timed 25-foot walk (T25FW), and gait testing. We examined associations using Spearman (r(s)) and partial Spearman correlation (pr(s)) analyses, using the entire sample and stratifying by disability status after controlling for age and sex. After controlling for age, sex, and disease duration, RD was significantly correlated (p<0.05) with step time (pr(s)=0.30). AD was significantly correlated (p<0.05) with step length (pr(s)=-0.32). MD was significantly associated (p<0.05) with 6MW (pr(s)=-0.35), T25FW (pr(s)=-0.34), gait velocity (pr(s)=-0.31), step time (pr(s)=0.29), and step length (pr(s)=-0.36). FA was not significantly correlated with any of the walking parameters (p>0.05). We provide novel evidence of possible motor pathway damage involved in walking performance in MS. There may be subtle differences in associations between MD, AD, and RD with walking outcomes, and these could be assessed in future longitudinal examinations and clinical trials of motor rehabilitation.

  6. Submaximal exercise testing in the assessment of interstitial lung disease secondary to systemic sclerosis: reproducibility and correlations of the 6‐min walk test

    PubMed Central

    Buch, M H; Denton, C P; Furst, D E; Guillevin, L; Rubin, L J; Wells, A U; Matucci‐Cerinic, M; Riemekasten, G; Emery, P; Chadha‐Boreham, H; Charef, P; Roux, S; Black, C M; Seibold, J R

    2007-01-01

    Background The 6‐min walk test (6MWT) is increasingly used as an outcome measure in interstitial lung disease (ILD). Aim To evaluate the usefulness of the 6MWT in a cohort of patients with ILD secondary to systemic sclerosis (SSc) and to correlate with established physiological parameters. Methods 163 patients with SSc‐ILD were recruited for a multicentre, randomised, double‐blind clinical trial. Available data at protocol screening included repeated 6MWTs, pulmonary function testing with diffusing capacity, Doppler echocardiography and high‐resolution computed tomography of the thorax. Borg Dyspnoea Index was evaluated before and after 6MWT. Results Mean (standard deviation (SD)) distance walked during walk test 1 was 396.6 (84.55) m compared with 399.5 (86.28) m at walk test 2. The within‐subject, intertest correlation as determined by Pearson's correlation coefficient testing was 0.95 (p<0.001). However, only weak correlations of 6MWT with percentage forced vital capacity and the Borg Dyspnoea Index were observed, and no correlation was observed with percentage diffusing capacity. Conclusion These data confirm the high reproducibility of the 6MWT in patients with SSc‐ILD and therefore the validity of the test in this cohort. The lack of correlation of 6MWT with standard physiological parameters of ILD suggests a multifactorial basis for limited exercise capacity in patients with SSc and calls into question the utility of the 6MWT as a measure of outcome in future studies on SSc‐ILD. PMID:16868020

  7. Plantar Temperature Response to Walking in Diabetes with and without Acute Charcot: The Charcot Activity Response Test

    PubMed Central

    Najafi, Bijan; Wrobel, James S.; Grewal, Gurtej; Menzies, Robert A.; Talal, Talal K.; Zirie, Mahmoud; Armstrong, David G.

    2012-01-01

    Objective. Asymmetric plantar temperature differences secondary to inflammation is a hallmark for the diagnosis and treatment response of Charcot foot syndrome. However, little attention has been given to temperature response to activity. We examined dynamic changes in plantar temperature (PT) as a function of graduated walking activity to quantify thermal responses during the first 200 steps. Methods. Fifteen individuals with Acute Charcot neuroarthropathy (CN) and 17 non-CN participants with type 2 diabetes and peripheral neuropathy were recruited. All participants walked for two predefined paths of 50 and 150 steps. A thermal image was acquired at baseline after acclimatization and immediately after each walking trial. The PT response as a function of number of steps was examined using a validated wearable sensor technology. The hot spot temperature was identified by the 95th percentile of measured temperature at each anatomical region (hind/mid/forefoot). Results. During initial activity, the PT was reduced in all participants, but the temperature drop for the nonaffected foot was 1.9 times greater than the affected side in CN group (P = 0.04). Interestingly, the PT in CN was sharply increased after 50 steps for both feet, while no difference was observed in non-CN between 50 and 200 steps. Conclusions. The variability in thermal response to the graduated walking activity between Charcot and non-Charcot feet warrants future investigation to provide further insight into the correlation between thermal response and ulcer/Charcot development. This stress test may be helpful to differentiate CN and its response to treatment earlier in its course. PMID:22900177

  8. Partial correlation between lower muscle thickness, 10-meter walk test, and the timed up & go test in children with spastic cerebral palsy.

    PubMed

    Yun, Chang-Kyo; Kim, Won-Hyo; Kim, Seong-Gil

    2016-05-01

    [Purpose] The purpose of this study was to examine the correlation between lower extremity muscle thickness and gait ability through the 10-meter walk and timed up and go tests. [Subjects and Methods] A total of 28 children (20 males and 8 females) with spastic cerebral palsy undergoing physical therapy at D hospital in D city, South Korea participated in this study. Partial correlation analysis was performed to analyze the correlation between lower extremity muscle thickness and gait ability (10-meter walk test and timed up and go test). [Results] There was a positive correlation between muscle thickness and the 10-meter walk test (RF=0.41 and VL=0.52). Correlation between the muscle thickness and the timed up and go had a negative correlation (VL=-0.45, MG=-0.51, and LG=-0.39). [Conclusion] In children with cerebral palsy, knee extensor muscles that are more developed increased gait ability and calf muscles that are more developed increased sit to stand ability.

  9. Criterion-Related Validity of the Distance- and Time-Based Walk/Run Field Tests for Estimating Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

    PubMed Central

    Mayorga-Vega, Daniel; Bocanegra-Parrilla, Raúl; Ornelas, Martha; Viciana, Jesús

    2016-01-01

    Objectives The main purpose of the present meta-analysis was to examine the criterion-related validity of the distance- and time-based walk/run tests for estimating cardiorespiratory fitness among apparently healthy children and adults. Materials and Methods Relevant studies were searched from seven electronic bibliographic databases up to August 2015 and through other sources. The Hunter-Schmidt’s psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the following walk/run tests: 5,000 m, 3 miles, 2 miles, 3,000 m, 1.5 miles, 1 mile, 1,000 m, ½ mile, 600 m, 600 yd, ¼ mile, 15 min, 12 min, 9 min, and 6 min. Results From the 123 included studies, a total of 200 correlation values were analyzed. The overall results showed that the criterion-related validity of the walk/run tests for estimating maximum oxygen uptake ranged from low to moderate (rp = 0.42–0.79), with the 1.5 mile (rp = 0.79, 0.73–0.85) and 12 min walk/run tests (rp = 0.78, 0.72–0.83) having the higher criterion-related validity for distance- and time-based field tests, respectively. The present meta-analysis also showed that sex, age and maximum oxygen uptake level do not seem to affect the criterion-related validity of the walk/run tests. Conclusions When the evaluation of an individual’s maximum oxygen uptake attained during a laboratory test is not feasible, the 1.5 mile and 12 min walk/run tests represent useful alternatives for estimating cardiorespiratory fitness. As in the assessment with any physical fitness field test, evaluators must be aware that the performance score of the walk/run field tests is simply an estimation and not a direct measure of cardiorespiratory fitness. PMID:26987118

  10. Improved Leg Tracking Considering Gait Phase and Spline-Based Interpolation during Turning Motion in Walk Tests.

    PubMed

    Yorozu, Ayanori; Moriguchi, Toshiki; Takahashi, Masaki

    2015-09-04

    Falling is a common problem in the growing elderly population, and fall-risk assessment systems are needed for community-based fall prevention programs. In particular, the timed up and go test (TUG) is the clinical test most often used to evaluate elderly individual ambulatory ability in many clinical institutions or local communities. This study presents an improved leg tracking method using a laser range sensor (LRS) for a gait measurement system to evaluate the motor function in walk tests, such as the TUG. The system tracks both legs and measures the trajectory of both legs. However, both legs might be close to each other, and one leg might be hidden from the sensor. This is especially the case during the turning motion in the TUG, where the time that a leg is hidden from the LRS is longer than that during straight walking and the moving direction rapidly changes. These situations are likely to lead to false tracking and deteriorate the measurement accuracy of the leg positions. To solve these problems, a novel data association considering gait phase and a Catmull-Rom spline-based interpolation during the occlusion are proposed. From the experimental results with young people, we confirm   that the proposed methods can reduce the chances of false tracking. In addition, we verify the measurement accuracy of the leg trajectory compared to a three-dimensional motion analysis system (VICON).

  11. Heart rate slopes during 6-min walk test in pulmonary arterial hypertension, other lung diseases, and healthy controls.

    PubMed

    Tonelli, Adriano R; Wang, Xiao-Feng; Alkukhun, Laith; Zhang, Qi; Dweik, Raed A; Minai, Omar A

    2014-06-01

    Six-minute walk test (6MWT) continues to be a useful tool to determine the functional capacity in patients with vascular and other lung diseases; nevertheless, it has a limited ability to predict prognosis in this context. We tested whether the heart rate (HR) acceleration and decay slopes during the 6-m walk test are different in patients with pulmonary arterial hypertension (PAH), other lung diseases, and healthy controls. In addition, we assessed whether the HR slopes are associated with clinical worsening. Using a portable, signal-morphology-based, impedance cardiograph (PhysioFlow Enduro, Paris, France) with real-time wireless monitoring via a Bluetooth USB adapter we determined beat-by-beat HR. We included 50 subjects in this pilot study, 20 with PAH (all on PAH-specific treatment), 17 with other lung diseases (obstructive [n = 12, 71%] or restrictive lung diseases [5, 29%]), and 13 healthy controls. The beat-by-beat HR curves were significantly different among all three groups of subjects either during the activity or recovery of the 6MWT. HR curves were less steep in PAH than the other two groups (P < 0.001). HR acceleration rates were slower in patients with PAH or other lung diseases with progression of their disease (P < 0.001). In conclusion, the acceleration and decay slopes during 6MWT are different among patients with PAH, other lung diseases, and healthy controls. The HR slopes during 6MWT were steeper in patients without clinical worsening.

  12. Heart rate slopes during 6‐min walk test in pulmonary arterial hypertension, other lung diseases, and healthy controls

    PubMed Central

    Tonelli, Adriano R.; Wang, Xiao‐Feng; Alkukhun, Laith; Zhang, Qi; Dweik, Raed A.; Minai, Omar A.

    2014-01-01

    Abstract Six‐minute walk test (6MWT) continues to be a useful tool to determine the functional capacity in patients with vascular and other lung diseases; nevertheless, it has a limited ability to predict prognosis in this context. We tested whether the heart rate (HR) acceleration and decay slopes during the 6‐m walk test are different in patients with pulmonary arterial hypertension (PAH), other lung diseases, and healthy controls. In addition, we assessed whether the HR slopes are associated with clinical worsening. Using a portable, signal‐morphology‐based, impedance cardiograph (PhysioFlow Enduro, Paris, France) with real‐time wireless monitoring via a Bluetooth USB adapter we determined beat‐by‐beat HR. We included 50 subjects in this pilot study, 20 with PAH (all on PAH‐specific treatment), 17 with other lung diseases (obstructive [n = 12, 71%] or restrictive lung diseases [5, 29%]), and 13 healthy controls. The beat‐by‐beat HR curves were significantly different among all three groups of subjects either during the activity or recovery of the 6MWT. HR curves were less steep in PAH than the other two groups (P < 0.001). HR acceleration rates were slower in patients with PAH or other lung diseases with progression of their disease (P < 0.001). In conclusion, the acceleration and decay slopes during 6MWT are different among patients with PAH, other lung diseases, and healthy controls. The HR slopes during 6MWT were steeper in patients without clinical worsening. PMID:24920122

  13. Six-month walking program changes cognitive and ADL performance in patients with Alzheimer.

    PubMed

    Venturelli, Massimo; Scarsini, Renato; Schena, Federico

    2011-08-01

    Motor inactivity is typical in the later stages of Alzheimer's disease although there is evidence that physical exercise can reduce depression and enhance performance of daily activities. The aim of this study was to determine whether a walking program could reduce the functional and cognitive decline of elderly nursing home residents in the later stages of Alzheimer's disease. A total of 21 patients (84 ± 5 years) were randomly assigned to a walking program (WG) or to a control group (CG). A 6-minute walking test (6WT), the Barthel index of activities of daily living (ADLs), and Mini-Mental State Examination (MMSE) tests were performed before and after 24 weeks of the program. The WG showed significant improvement in the 6WT (20%) and ADLs (23%), while the CG decreased in MMSE (-47%), the WG had a slower decline (-13%). This study indicates that it is possible to stabilize the progressive cognitive dysfunctions in nursing home residents with Alzheimer's disease through a specific walking program.

  14. Inter and Intra Rater Reliability of the 10 Meter Walk Test in the Community Dweller Adults with Spastic Cerebral Palsy

    PubMed Central

    BAHRAMI, Fariba; NOORIZADEH DEHKORDI, Shohreh; DADGOO, Mehdi

    2017-01-01

    Objective We aimed to investigation the intra-rater and inter-raters reliability of the 10 meter walk test (10 MWT) in adults with spastic cerebral palsy (CP). Materials & Methods Thirty ambulatory adults with spastic CP in the summer of 2014 participated (19 men, 11 women; mean age 28 ± 7 yr, range 18- 46 yr). Individuals were non-randomly selected by convenient sampling from the Ra’ad Rehabilitation Goodwill Complex in Tehran, Iran. They had GMFCS levels below IV (I, II, and III). Retest interval for inter-raters study lasted a week. During the tests, participants walked with their maximum speed. Intraclass correlation coefficients (ICC) estimated reliability. Results The 10 MWT ICC for intra-rater was 0.98 (95% confidence interval (CI) 0.96-0.99) for participants, and >0.89 in GMFCS subgroups (95% confidence interval (CI) lower bound>0.67). The 10 MWT inter-raters’ ICC was 0.998 (95% confidence interval (CI) 0/996-0/999), and >0.993 in GMFCS subgroups (95% confidence interval (CI) lower bound>0.977). Standard error of the measurement (SEM) values for both studies was small (0.02< SEM< 0.07). Conclusion Excellent intra-rater and inter-raters reliability of the 10 MWT in adults with CP, especially in the moderate motor impairments (GMFCS level III), indicates that this tool can be used in clinics to assess the results of interventions. PMID:28277557

  15. Hypoxemia and arrhythmia during daily activities and six-minute walk test in fibrotic interstitial lung diseases.

    PubMed

    Park, Jeong Hyun; Jegal, Yangjin; Shim, Tae Sun; Lim, Chae-Man; Lee, Sang Do; Koh, Younsuck; Kim, Woo Sung; Kim, Won Dong; du Bois, Roland; Do, Kyung-Hyun; Kim, Dong Soon

    2011-03-01

    We performed 24-hr monitoring of pulse oximetric saturation (SpO(2)) with ECG and six-minute walk test (6MWT) in 19 patients with fibrotic interstitial lung diseases (ILD) to investigate; 1) The frequency and severity of hypoxemia and dysrhythmia during daily activities and 6MWT, 2) safety of 6MWT, and 3) the parameters of 6MWT which can replace 24-hr continuous monitoring of SpO(2) to predict hypoxemia during daily activities. All patients experienced waking hour hypoxemia, and eight of nineteen patients spent > 10% of waking hours in hypoxemic state. Most patients experienced frequent arrhythmia, mostly atrial premature contractions (APCs) and ventricular premature contractions (VPCs). There were significant correlation between the variables of 6MWT and hypoxemia during daily activities. All of the patients who desaturated below 80% before 300 meters spent more than 10% of waking hour in hypoxemia (P = 0.018). In contrast to waking hour hypoxemia, SpO(2) did not drop significantly during sleep except in the patients whose daytime resting SpO(2) was already low. In conclusion, patients with fibrotic ILD showed significant period of hypoxemia during daily activities and frequent VPCs and APCs. Six-minute walk test is a useful surrogate marker of waking hour hypoxemia and seems to be safe without continuous monitoring of SpO(2).

  16. The Walk on Floor Eyes Closed Tandem Step Test as a Quantitative Measure of Ataxia After Space Flight

    NASA Technical Reports Server (NTRS)

    Fisher, E. A.; Reschke, M. F.; Kofman, I. S.; Cerisano, J. M.; Lawrence, E. L.; Peters, B. T.; Bloomberg, J. J.; Harm, D. L.

    2010-01-01

    INTRODUCTION Posture and locomotion are among the functions most affected by space flight. Postflight ataxia can be quantified easily by using the walk on the floor line test with the eyes closed (WOFEC). Data from a modified WOFEC were obtained as part of an ongoing interdisciplinary pre- and postflight study (Functional Task Test, FTT) designed to evaluate both postflight functional performance of astronauts and related physiological changes. METHODS Five astronauts with flight durations of 12 to 16 days participated in this study. Performance measurements were obtained in 2 preflight sessions, on landing day, and 1, 6, and 30 days after landing. The WOFEC test consisted of walking with the feet placed heel to toe in tandem, arms folded across the chest and eyes closed, for 10 steps. A trial was initiated after the eyes were closed and the front foot was aligned with the rear foot. The performance metric was the average percentage of correct steps completed over 3 trials. A step was not counted as correct if the crewmember sidestepped, opened eyes, or paused for more than 3 seconds between steps. Step accuracy was scored independently by 3 examiners. RESULTS Immediately after landing subjects seemed to be unaware of their foot position relative to their body or the floor. The percentage of correct steps was significantly decreased on landing day. Partial recovery was observed the next day, and full recovery to baseline on the sixth day post landing. CONCLUSION These data clearly demonstrate the sensorimotor challenges facing crewmembers after they return from space flight. Although this simple test is intended to complement the FTT battery of tests, it has some stand-alone value as it provides investigators with a means to quantify vestibular ataxia as well as provide instant feedback on postural stability without the use of complex test equipment.

  17. How to walk a conveyor

    SciTech Connect

    2007-06-15

    The article gives a check list of what one should know before walking a belt conveyor, and what to do during the walk. It then presents a list of what to look at on a walk along the conveyor system (excluding related equipment which could be inspected or maintained during the walk). It gives advice on when to stop the conveyor, on testing the emergency stop system, on recording problems and on acting on things noted. 1 tab.

  18. Load carrying walking test and its relationships to endurance and neuromuscular capabilities in women and men of different ages.

    PubMed

    Holviala, J; Häkkinen, A; Nyman, K; Aho, J; Karavirta, L; Häkkinen, K

    2011-03-01

    The aim of this study was to examine load carrying walking test (TMload) performance on the treadmill and its associations to endurance and neuromuscular capabilities in women and men of different ages. Sixty participants (aged 28 to 71 years) were divided into young, middle-aged and old groups of both genders. Clinical stress test was performed by stationary cycle ergometer (CEload). Peak oxygen uptake (VO2peak), heart rate and lactate concentration were measured using maximal TMload test. Isometric strength and EMG-activity of upper and lower extremities were measured before and after TMload. VO2peak of TMload correlated significantly with TMload exercise time (ET) in all other groups (r=0.67 to 0.91 and p ≤ 0.05 to p<0.001) except old men. Leg extension force decreased (p ≤ 0.05 to p<0.001) after TMload in all groups, grip force in young groups (p ≤ 0.05), while plantar flexion force and all EMGs remained unchanged. In men VO2peak explained 81% and in women VO2peak and age explained 87% of the total variation of the TMload ET. In conclusion, ET of TMload is associated with high VO2peak, but not with muscle strength or its changes during the loading. The present load carrying walking test may be used for testing workers with heavy loading in their occupation or in rehabilitation purposes. Further research is needed to examine in more detailed the loading model of the present study as well as the effects of different types of training on load carrying performance.

  19. Reproducibility for Heart Rate Variability Analysis during 6-Min Walk Test in Patients with Heart Failure and Agreement between Devices

    PubMed Central

    Braga, Lays Magalhães; Prado, Gustavo Faibischew; Umeda, Iracema Ioco Kikuchi; Kawauchi, Tatiana Satie; Taboada, Adriana Marques Fróes; Azevedo, Raymundo Soares; Pereira Filho, Horacio Gomes; Grupi, César José; Souza, Hayala Cristina Cavenague; Moreira, Dalmo Antônio Ribeiro

    2016-01-01

    Heart rate variability (HRV) analysis is a useful method to assess abnormal functioning in the autonomic nervous system and to predict cardiac events in patients with heart failure (HF). HRV measurements with heart rate monitors have been validated with an electrocardiograph in healthy subjects but not in patients with HF. We explored the reproducibility of HRV in two consecutive six-minute walk tests (6MW), 60-minute apart, using a heart rate monitor (PolarS810i) and a portable electrocardiograph (called Holter) in 50 HF patients (mean age 59 years, NYHA II, left ventricular ejection fraction ~35%). The reproducibility for each device was analysed using a paired t-test or the Wilcoxon signed-rank test. Additionally, we assessed the agreement between the two devices based on the HRV indices at rest, during the 6MW and during recovery using concordance correlation coefficients (CCC), 95% confidence intervals and Bland-Altman plots. The test-retest for the HRV analyses was reproducible using Holter and PolarS810i at rest but not during recovery. In the second 6MW, patients showed significant increases in rMSSD and walking distance. The PolarS810i measurements had remarkably high concordance correlation [0.86

  20. Reproducibility for Heart Rate Variability Analysis during 6-Min Walk Test in Patients with Heart Failure and Agreement between Devices.

    PubMed

    Braga, Lays Magalhães; Prado, Gustavo Faibischew; Umeda, Iracema Ioco Kikuchi; Kawauchi, Tatiana Satie; Taboada, Adriana Marques Fróes; Azevedo, Raymundo Soares; Pereira Filho, Horacio Gomes; Grupi, César José; Souza, Hayala Cristina Cavenague; Moreira, Dalmo Antônio Ribeiro; Nakagawa, Naomi Kondo

    2016-01-01

    Heart rate variability (HRV) analysis is a useful method to assess abnormal functioning in the autonomic nervous system and to predict cardiac events in patients with heart failure (HF). HRV measurements with heart rate monitors have been validated with an electrocardiograph in healthy subjects but not in patients with HF. We explored the reproducibility of HRV in two consecutive six-minute walk tests (6MW), 60-minute apart, using a heart rate monitor (PolarS810i) and a portable electrocardiograph (called Holter) in 50 HF patients (mean age 59 years, NYHA II, left ventricular ejection fraction ~35%). The reproducibility for each device was analysed using a paired t-test or the Wilcoxon signed-rank test. Additionally, we assessed the agreement between the two devices based on the HRV indices at rest, during the 6MW and during recovery using concordance correlation coefficients (CCC), 95% confidence intervals and Bland-Altman plots. The test-retest for the HRV analyses was reproducible using Holter and PolarS810i at rest but not during recovery. In the second 6MW, patients showed significant increases in rMSSD and walking distance. The PolarS810i measurements had remarkably high concordance correlation [0.86

  1. Six-minute walk test and respiratory muscle strength in patients with uncontrolled severe asthma: a pilot study*

    PubMed Central

    Pereira, Luiz Fernando Ferreira; Mancuzo, Eliane Viana; Rezende, Camila Farnese; Côrrea, Ricardo de Amorim

    2015-01-01

    OBJECTIVE: To evaluate respiratory muscle strength and six-minute walk test (6MWT) variables in patients with uncontrolled severe asthma (UCSA). METHODS: This was a cross-sectional study involving UCSA patients followed at a university hospital. The patients underwent 6MWT, spirometry, and measurements of respiratory muscle strength, as well as completing the Asthma Control Test (ACT). The Mann-Whitney test was used in order to analyze 6MWT variables, whereas the Kruskal-Wallis test was used to determine whether there was an association between the use of oral corticosteroids and respiratory muscle strength. RESULTS: We included 25 patients. Mean FEV1 was 58.8 ± 21.8% of predicted, and mean ACT score was 14.0 ± 3.9 points. No significant difference was found between the median six-minute walk distance recorded for the UCSA patients and that predicted for healthy Brazilians (512 m and 534 m, respectively; p = 0.14). During the 6MWT, there was no significant drop in SpO2. Mean MIP and MEP were normal (72.9 ± 15.2% and 67.6 ± 22.2%, respectively). Comparing the patients treated with at least four courses of oral corticosteroids per year and those treated with three or fewer, we found no significant differences in MIP (p = 0.15) or MEP (p = 0.45). CONCLUSIONS: Our findings suggest that UCSA patients are similar to normal subjects in terms of 6MWT variables and respiratory muscle strength. The use of oral corticosteroids has no apparent impact on respiratory muscle strength. PMID:26176518

  2. Evaluation of Timed Up and Go Test as a tool to measure postoperative function and prediction of one year walking ability for patients with hip fracture

    PubMed Central

    Nygard, Heid; Matre, Kjell; Fevang, Jonas Meling

    2015-01-01

    Objective: To evaluate if the Timed Up and Go Test is a useful tool to measure postoperative function and to predict one-year results of rehabilitation in patients operated owing to hip fracture. Design: Prospective cohort study. Setting: The department of orthopaedic surgery at five hospitals in Norway. Patients were assessed five days postoperatively and after one year. Subjects: A total of 684 patients over 60 years with trochanteric or subtrochanteric hip fractures were included. A total of 171 (25%) patients died within a year and 373 (73% of patients still alive) attended follow-up one year after surgery. Main measures: Timed Up and Go Test and walking ability. Results: A total of 258 (38%) patients passed the postoperative Timed Up and Go Test. A total of 217 (56%) patients with a prefracture independent outdoor walking ability, passed the test. The average Timed Up and Go Test score was 71 seconds. A total of 171 (25%) patients could not rise from a chair without assistance; 8% of the patients with cognitive impairment, and 8% of those admitted from nursing homes, were able to pass the postoperative Timed Up and Go Test. The sensitivity and specificity of the Timed Up and Go Test in predicting walking ability one year after the operation were low. At one year follow-up, 38% of the patients not able to perform the postoperative Timed Up and Go Test, passed the test. A total of 81 (21%) patients did not use any walking-aid, 17 of them did not pass the postoperative Timed Up and Go Test. Conclusion: The Timed Up and Go Test performed the fifth postoperative day was not a suitable tool to assess functional mobility for the majority of the patients with hip fractures in our study. Neither was the postoperative Timed Up and Go Test a suitable tool to predict the walking ability one year after the operation. PMID:26109590

  3. Testing the imprint of nonstandard cosmologies on void profiles using Monte Carlo random walks

    NASA Astrophysics Data System (ADS)

    Achitouv, Ixandra

    2016-11-01

    Using Monte Carlo random walks of a log-normal distribution, we show how to qualitatively study void properties for nonstandard cosmologies. We apply this method to an f (R ) modified gravity model and recover the N -body simulation results of [1 I. Achitouv, M. Baldi, E. Puchwein, and J. Weller, Phys. Rev. D 93, 103522 (2016).] for the void profiles and their deviation from GR. This method can potentially be extended to study other properties of the large scale structures such as the abundance of voids or overdense environments. We also introduce a new way to identify voids in the cosmic web, using only a few measurements of the density fluctuations around random positions. This algorithm allows us to select voids with specific profiles and radii. As a consequence, we can target classes of voids with higher differences between f (R ) and standard gravity void profiles. Finally, we apply our void criteria to galaxy mock catalogues and discuss how the flexibility of our void finder can be used to reduce systematic errors when probing the growth rate in the galaxy-void correlation function.

  4. Questionnaire, walking time and button test measures of functional capacity as predictive markers for mortality in rheumatoid arthritis.

    PubMed

    Pincus, T; Callahan, L F; Vaughn, W K

    1987-04-01

    Mortality over 9 years in rheumatoid arthritis was studied according to baseline demographic, disease, therapy and comorbidity variables, and measures of functional capacity variables. Significant differences between patients who survived and died over the next 9 years were seen for 8 variables: age, joint count, oral corticosteroid use, presence of concurrent heart disease, formal educational level, and 3 quantitative measures of functional capacity, questionnaire responses regarding activities of daily living, modified walking time and the button test. Five-year survivals of 50% or less were seen in patients with severely dysfunctional values for the 3 quantitative measures of functional capacity. Increased relative risk of mortality according to functional capacity measures was not explained by age, sex, duration of disease, smoking history, joint count, hand radiograph score, grip strength, morning stiffness, formal educational level, oral corticosteroid or parenteral gold use, or various comorbidities, and was not expected by a majority of physicians.

  5. Heart Rate Recovery in the First Minute at the Six-Minute Walk Test in Patients with Heart Failure

    PubMed Central

    Lindemberg, Sabrina; Chermont, Sergio; Quintão, Mônica; Derossi, Milena; Guilhon, Sergio; Bernardez, Sabrina; Marchese, Luana; Martins, Wolney; Nóbrega, Antônio Claudio L.; Mesquita, Evandro Tinoco

    2014-01-01

    Background Heart rate recovery at one minute of rest (HRR1) is a predictor of mortality in heart failure (HF), but its prognosis has not been assessed at six-minute walk test (6MWT) in these patients. Objective This study aimed to determine the HRR1 at 6MWT in patients with HF and its correlation with six-minute walk distance (6MWD). Methods Cross-sectional, controlled protocol with 161 individuals, 126 patients with stable systolic HF, allocated into 2 groups (G1 and G2) receiving or not β-blocker and 35 volunteers in control group (G3) had HRR1 recorded at the 6MWT. Results HRR1 and 6MWD were significantly different in the 3 groups. Mean values of HRR1 and 6MWD were: HRR1 = 12 ± 14 beat/min G1; 18 ± 16 beat/min G2 and 21 ± 13 beat/min G3; 6MWD = 423 ± 102 m G1; 396 ± 101m G2 and 484 ± 96 m G3 (p < 0.05). Results showed a correlation between HRR1 and 6MWD in G1(r = 0.3; p = 0.04) and in G3(r = 0.4; p= 0.03), but not in G2 (r= 0.12; p= 0.48). Conclusion HRR1 response was attenuated in patients using βB and showed correlation with 6MWD, reflecting better exercise tolerance. HRR1 after 6MWT seems to represent an alternative when treadmill tests could not be tolerated. PMID:24714794

  6. Reference values for the incremental shuttle walk test in patients with cardiovascular disease entering exercise-based cardiac rehabilitation.

    PubMed

    Cardoso, Fernando M F; Almodhy, Meshal; Pepera, Garyfalia; Stasinopoulos, Dimitrios M; Sandercock, Gavin R H

    2017-01-01

    The incremental shuttle walk test (ISWT) is used to assess functional capacity of patients entering cardiac rehabilitation. Factors such as age and sex account for a proportion of the variance in test performance in healthy individuals but there are no reference values for patients with cardiovascular disease. The aim of this study was to produce reference values for the ISWT. Participants were n = 548 patients referred to outpatient cardiac rehabilitation who underwent a clinical examination and performed the ISWT. We used regression to identify predictors of performance and produced centile values using the generalised additive model for location, scale and shape model. Men walked significantly further than women (395 ± 165 vs. 269 ± 118 m; t = 9.5, P < 0.001) so data were analysed separately by sex. Age (years) was the strongest predictor of performance in men (β = -5.9; 95% CI: -7.1 to -4.6 m) and women (β = -4.8; 95% CI: -6.3 to 3.3). Centile curves demonstrated a broadly linear decrease in expected ISWT values in males (25-85 years) and a more curvilinear trend in females. Patients entering cardiac rehabilitation present with highly heterogeneous ISWT values. Much of the variance in performance can be explained by patients' age and sex. Comparing absolute values with age-and sex-specific reference values may aid interpretation of ISWT performance during initial patient assessment at entry to cardiac rehabilitation.

  7. Validity and reliability of the 1/4 mile run-walk test in physically active children and adolescents.

    PubMed

    Ruiz, Jonatan R; Ortega, Francisco B; Castro-Piñero, Jose

    2014-11-30

    We investigated the criterion-related validity and the reliability of the 1/4 mile run-walk test (MRWT) in children and adolescents. A total of 86 children (n=42 girls) completed a maximal graded treadmill test using a gas analyzer and the 1/4MRW test. We investigated the test-retest reliability of the 1/4MRWT in a different group of children and adolescents (n=995, n=418 girls). The 1/4MRWT time, sex, and BMI significantly contributed to predict measured VO2peak (R2= 0.32). There was no systematic bias in the cross-validation group (P>0.1). The root mean sum of squared errors (RMSE) and the percentage error were 6.9 ml/kg/min and 17.7%, respectively, and the accurate prediction (i.e. the percentage of estimations within ±4.5 ml/kg/min of VO2peak) was 48.8%. The reliability analysis showed that the mean inter-trial difference ranged from 0.6 seconds in children aged 6-11 years to 1.3 seconds in adolescents aged 12-17 years (all P.

  8. Walk a Mile in My Shoes: Stakeholder Accounts of Testing Experience with a Computer-Administered Test

    ERIC Educational Resources Information Center

    Fox, Janna; Cheng, Liying

    2015-01-01

    In keeping with the trend to elicit multiple stakeholder responses to operational tests as part of test validation, this exploratory mixed methods study examines test-taker accounts of an Internet-based (i.e., computer-administered) test in the high-stakes context of proficiency testing for university admission. In 2013, as language testing…

  9. An Evaluation of the Canadian Forces Two-Mile Walk as a Test of Aerobic Fitness in Males over 45 Years of Age

    DTIC Science & Technology

    1977-03-01

    individuals have a rather sedentary lifestyle and do not realize the benefits of regular exercise. Since, for a variety of reasons, they are often...categories of "good" and "excellent" indicated by the walk test were high in view of the mainly sedentary lifestyle of the twelve subjects. These

  10. Walking Problems

    MedlinePlus

    ... Parkinson's disease Diseases such as arthritis or multiple sclerosis Vision or balance problems Treatment of walking problems depends on the cause. Physical therapy, surgery, or mobility aids may help.

  11. Pilot Field Test: Results of Tandem Walk Performance Following Long-Duration Spaceflight

    NASA Technical Reports Server (NTRS)

    Cerisano, J. M.; Reschke, M. F.; Kofman, I. S.; Fisher, E. A.; Gadd, N. E.; Phillips, T. R.; Lee, S. M. C.; Laurie, S. S.; Stenger, M. B.; Bloomberg, J. J.; Mulavara, A.; Kozlovskaya, I.; Tomilovskaya, E.

    2016-01-01

    Coordinated locomotion has proven to be challenging for many astronauts following long duration spaceflight. As NASA's vision for spaceflight points toward interplanetary travel and missions to distant objects, astronauts will not have assistance once they land. Thus, it is vital to develop a knowledge base from which operational guidelines can be written that define when astronauts can be expected to safely perform certain tasks. Data obtained during the Field Test experiment will add important insight to this knowledge base. Specifically, we aim to develop a recovery timeline of functional sensorimotor performance during the first 24 hours and several days after landing. A forerunner of the full Field Test study, the Pilot Field Test (PFT) comprised a subset of the tasks and measurements to be included in the ultimate set.

  12. Role of the cardio-pulmonary exercise test and six-minute walking test in the evaluation of exercise performance in patients with late-onset Pompe disease.

    PubMed

    Crescimanno, G; Modica, R; Lo Mauro, R; Musumeci, O; Toscano, A; Marrone, O

    2015-07-01

    In patients with late-onset Pompe disease, we explored the role of the Cardiopulmonary Exercise Test (CPET) and the Six-Minute Walking Test (6MWT) in the assessment of exercise capacity and in the evaluation of the effects of enzyme replacement therapy (ERT). Eight patients affected by late-onset Pompe disease, followed up at the Centre for Neuromuscular Diseases and treated with ERT, underwent a baseline evaluation with a spirometry, a CPET and a 6MWT. Four of them were restudied after 36 months of treatment. Three patients showed a reduction in exercise capacity as evaluated by peak oxygen uptake (VO2) measured at the CPET and Distance Walked (DW) measured at the 6MWT (median % predicted: 67.1 [range 54.3-99.6] and 67.3 [56.6-82.6], respectively). Cardiac and respiratory limitations revealed by the CPET were correlated to peak VO2, but not to the DW. Nevertheless, percent of predicted values of peak VO2 and DW were strongly correlated (rho = 0.85, p = 0.006), and close to identity. In the longitudinal evaluation forced vital capacity decreased, while peak VO2 and DW showed a trend to a parallel improvement. We concluded that although only the CPET revealed causes of exercise limitation, which partially differed among patients, CPET and 6MWT showed a similar overall degree of exercise impairment. That held true in the longitudinal assessment during ERT, where both tests demonstrated similar small improvements, occurring despite deterioration in forced vital capacity.

  13. A randomized controlled trial of telephone-mentoring with home-based walking preceding rehabilitation in COPD

    PubMed Central

    Cameron-Tucker, Helen Laura; Wood-Baker, Richard; Joseph, Lyn; Walters, Julia A; Schüz, Natalie; Walters, E Haydn

    2016-01-01

    Purpose With the limited reach of pulmonary rehabilitation (PR) and low levels of daily physical activity in chronic obstructive pulmonary disease (COPD), a need exists to increase daily exercise. This study evaluated telephone health-mentoring targeting home-based walking (tele-rehab) compared to usual waiting time (usual care) followed by group PR. Patients and methods People with COPD were randomized to tele-rehab (intervention) or usual care (controls). Tele-rehab delivered by trained nurse health-mentors supported participants’ home-based walking over 8–12 weeks. PR, delivered to both groups simultaneously, included 8 weeks of once-weekly education and self-management skills, with separate supervised exercise. Data were collected at three time-points: baseline (TP1), before (TP2), and after (TP3) PR. The primary outcome was change in physical capacity measured by 6-minute walk distance (6MWD) with two tests performed at each time-point. Secondary outcomes included changes in self-reported home-based walking, health-related quality of life, and health behaviors. Results Of 65 recruits, 25 withdrew before completing PR. Forty attended a median of 6 (4) education sessions. Seventeen attended supervised exercise (5±2 sessions). Between TP1 and TP2, there was a statistically significant increase in the median 6MWD of 12 (39.1) m in controls, but no change in the tele-rehab group. There were no significant changes in 6MWD between other time-points or groups, or significant change in any secondary outcomes. Participants attending supervised exercise showed a nonsignificant improvement in 6MWD, 12.3 (71) m, while others showed no change, 0 (33) m. The mean 6MWD was significantly greater, but not clinically meaningful, for the second test compared to the first at all time-points. Conclusion Telephone-mentoring for home-based walking demonstrated no benefit to exercise capacity. Two 6-minute walking tests at each time-point may not be necessary. Supervised exercise

  14. Cardiorespiratory Responses and Prediction of Peak Oxygen Uptake during the Shuttle Walking Test in Healthy Sedentary Adult Men

    PubMed Central

    Neves, Camila D. C.; Lacerda, Ana Cristina Rodrigues; Lage, Vanessa K. S.; Lima, Liliana P.; Fonseca, Sueli F.; de Avelar, Núbia C. P.; Teixeira, Mauro M.; Mendonça, Vanessa A.

    2015-01-01

    Background The application of the Shuttle Walking Test (SWT) to assess cardiorespiratory fitness and the intensity of this test in healthy participants has rarely been studied. This study aimed to assess and correlate the cardiorespiratory responses of the SWT with the cardiopulmonary exercise testing (CEPT) and to develop a regression equation for the prediction of peak oxygen uptake (VO2 peak) in healthy sedentary adult men. Methods In the first stage of this study, 12 participants underwent the SWT and the CEPT on a treadmill. In the second stage, 53 participants underwent the SWT twice. In both phases, the VO2 peak, respiratory exchange ratio (R), and heart rate (HR) were evaluated. Results Similar results in VO2 peak (P>0.05), R peak (P>0.05) and predicted maximum HR (P>0.05) were obtained between the SWT and CEPT. Both tests showed strong and significant correlations of VO2 peak (r = 0.704, P = 0.01) and R peak (r = 0.737, P<0.01), as well as the agreement of these measurements by Bland-Altman analysis. Body mass index and gait speed were the variables that explained 40.6% (R2 = 0.406, P = 0.001) of the variance in VO2 peak. The results obtained by the equation were compared with the values obtained by the gas analyzer and no significant difference between them (P>0.05) was found. Conclusions The SWT produced maximal cardiorespiratory responses comparable to the CEPT, and the developed equation showed viability for the prediction of VO2 peak in healthy sedentary men. PMID:25659094

  15. The Effect of Maximal Strength Training on Strength, Walking, and Balance in People with Multiple Sclerosis: A Pilot Study

    PubMed Central

    Klein, Sarah; Park, David; Wright, Charles; Zervas, Michael

    2016-01-01

    There is little literature examining the use of maximal strength training (MST) in people with multiple sclerosis (pwMS). This pretest-posttest study examined the effects of a MST program on strength, walking, balance, and fatigue in a sample of pwMS. Seven pwMS (median EDSS 3.0, IQR 1.5) participated in a MST program twice weekly for eight weeks. Strength was assessed with 1-repetition maximum (1RM) on each leg. Walking and balance were measured with the 6-Minute Walk Test (6MWT) and Berg Balance Scale (BBS), respectively. Fatigue was measured during each week of the program with the Fatigue Severity Scale (FSS). The program was well tolerated, with an attendance rate of 96.4%. Participants had significant improvements in right leg 1RM (t(6) = −6.032, P = 0.001), left leg 1RM (t(6) = −5.388, P = 0.002), 6MWT distance (t(6) = −2.572, P = 0.042), and BBS score (Z = −2.371, P = 0.018) after the MST intervention. There was no significant change in FSS scores (F(1, 3.312) = 2.411, P = 0.092). Participants in the MST program experienced improved balance and walking without an increase in fatigue. This MST program may be utilized by rehabilitation clinicians to improve lower extremity strength, balance, and mobility in pwMS. PMID:28116161

  16. Anatomic correlates of reduced hip extension during walking in individuals with mild-moderate radiographic hip osteoarthritis

    PubMed Central

    Kumar, Deepak; Wyatt, Cory; Chiba, Ko; lee, Sonia; Nardo, Lorenzo; Link, Thomas M.; Majumdar, Sharmila; Souza, Richard B.

    2014-01-01

    Purpose To identify radiographic and MR features of hip osteoarthritis (OA) related to reduced hip extension during walking. Methods Sixty six subjects, were stratified into those with (n = 36, KL = 2, 3) and without (n = 30, KL = 0, 1) radiographic hip OA. Cartilage and labrum lesions were graded semi-quantitatively on hip MRI. Alpha angle and lateral center edge (LCE) angle were measured. Sagittal kinematics and kinetics were calculated during walking at speed of 1.3 m/sec using 3-D motion capture. All subjects completed Hip disability and Osteoarthritis Outcome Score (HOOS), timed up and go, and 6 minute walk tests. Variables were compared between the two groups using one-way ANOVA (adjusting for age). Correlations of radiographic and MR parameters with peak hip extension were calculated. Results The OA group was older, had greater pain, and limitation of function. They also had lower peak hip extension and higher peak hip flexion; and worse acetabular and femoral cartilage lesions. Peak hip extension and flexion correlated with KL grade, cartilage lesions in the inferior and posterior femur. Conclusions Reduced hip extension and greater hip flexion during walking are present in high functioning (HOOS > 85%) individuals with mild-moderate hip OA, and is associated with cartilage lesions. PMID:25678302

  17. Evaluation of the microsoft kinect skeletal versus depth data analysis for timed-up and go and figure of 8 walk tests.

    PubMed

    Hotrabhavananda, Benjamin; Mishra, Anup K; Skubic, Marjorie; Hotrabhavananda, Nijaporn; Abbott, Carmen

    2016-08-01

    We compared the performance of the Kinect skeletal data with the Kinect depth data in capturing different gait parameters during the Timed-up and Go Test (TUG) and Figure of 8 Walk Test (F8W). The gait parameters considered were stride length, stride time, and walking speed for the TUG, and number of steps and completion time for the F8W. A marker-based Vicon motion capture system was used for the ground-truth measurements. Five healthy participants were recruited for the experiment and were asked to perform three trials of each task. Results show that depth data analysis yields stride length and stride time measures with significantly low percentile errors as compared to the skeletal data analysis. However, the skeletal and depth data performed similar with less than 3% of absolute mean percentile error in determining the walking speed for the TUG and both parameters of F8W. The results show potential capabilities of Kinect depth data analysis in computing many gait parameters, whereas, the Kinect skeletal data can also be used for walking speed in TUG and F8W gait parameters.

  18. Design and Testing of a 2-Hour Oxygen Prebreathe Protocol for Space Walks from the International Space Station

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael L.; Conkin, J.; Foster, P. P.; Pilmanis, A. A.; Butler, B. D.; Beltran, E.; Fife, C. E.; Vann, R. D.; Gerth, W. A.; Loftin, K. C.; Paloski, William H. (Technical Monitor)

    2000-01-01

    To develop and test a 2-hour prebreathe protocol for performing extravehicular activities (EVAs) from the International Space Station (ISS). Combinations of adynamia (non-walking), prebreathe exercise, and space suit donning options (10.2 vs. 14.7 psi) were evaluated, against timeline and consumable contraints to develop an operational 2- hour prebreathe protocol. Prospective accept/reject criteria were defined for decompression sickness (DCS) and venous gas emboli (VGE) from analysis of historical DCS data, combined with risk management of DCS under ISS mission circumstances. Maximum operational DCS levels were defined based on protecting for EVA capability with two crew-members at 95% confidence, throughout ISS lifetime (within the constraints of NASA DCS disposition policy JPG 1800.3). The accept/reject limits were adjusted for greater safety based on analysis of related medical factors. Monte-Carlo simulation was performed to design a closed sequential, multi-center human trial. Protocols were tested with 4 different prebreathe exercises (Phases I-IV), prior to exposure to 4.3 psi for 4 hrs. Subject selection, Doppler monitoring for VGE, test termination criteria, and DCS definitions were standardized. Phase I: upper and lower body exercises using dual-cycle ergometry (75% VO2 max for 10 min). Phase II: ergometry plus 24 min of light exercise (simulating space-suit preparations). Phase III: same 24 min of light exercise but no ergometry, and Phase IV: 56 min of light exercise without ergometry. A prebreathe procedure was accepted if, at 95% confidence, the incidence of DCS was less than 15% (with no Type II DCS), and Grade IV VGE was less than 20%.

  19. [Clinical validity of the quantitative gait variables in patients with multiple sclerosis. A comparison of the Timed 25-foot Walk Test and the GAITRite ® Electronic Walkway system].

    PubMed

    Hochsprung, A; Heredia-Camacho, B; Castillo, M; Izquierdo, G; Escudero-Uribe, S

    2014-07-01

    INTRODUCTION. Multiple sclerosis is an inflammatory and degenerative disease in which gait alteration is one of the first symptoms. Its quantitative evaluation is often made by the Timed 25-foot Walk Test (T25FW), although it's limited to know only the distance, the time employed and number of steps. AIM. To compare the T25FW with the results from the GAITRite ® Electronic Walkway system (GEW), to know if there is some variability between them. PATIENTS AND METHODS. The sample consisted in 85 subjects with multiple sclerosis and able to walking, with or without aids (EDSS: 1.0-6.5). Four walkings were made along the 8 m-length carpet from GEW system, while a different evaluator measured the time employed with a chronometer, and the number of steps in a 25 feet distance marked side by side in the carpet. Velocity was calculated in function of distance and time employed. A mean from the four walkings was made and both of the measures were correlated with SPSS v. 18, considering a results of p < 0.001, statistically significant. RESULTS. Time employed (p = 1.000), velocity (p = 0.9995), cadence (p = 0.3296) and number of steps (p = 1.000) were not statistically different. CONCLUSIONS. GEW system has the same clinical validity in gait evaluation in multiple sclerosis patients than the T25FW.

  20. The effect of reduced gravity on the kinematics of human walking: a test of the dynamic similarity hypothesis for locomotion.

    PubMed

    Donelan, J M; Kram, R

    1997-12-01

    To gain insight into the basic principles that govern the biomechanics of locomotion, we investigated the effect of reduced gravity on walking kinematics. We hypothesized that humans walk in a dynamically similar fashion at combinations of speed and simulated gravity that provide equal values of the Froude number, v2/gLleg, where v is forward speed, g is gravitational acceleration and Lleg is leg length. The Froude number has been used to predict the kinematics and kinetics of legged locomotion over a wide range of animal sizes and speeds, and thus provides a potentially unifying theory for the combined effects of speed, size and gravity on locomotion biomechanics. The occurrence of dynamic similarity at equal Froude numbers has been attributed previously to the importance of gravitational forces in determining locomotion mechanics. We simulated reduced gravity using a device that applies a nearly constant upward force to the torso while subjects walked on a treadmill. We found that at equal Froude numbers, under different levels of gravity (0.25g-1.0g), the subjects walked with nearly the same duty factor (ratio of contact time to stride time), but with relative stride lengths (Ls/Lleg, where Ls is stride length) that differed by as much as 67 %, resulting in the rejection of our hypothesis. To understand the separate effects of speed and gravity further, we compared the mechanics of walking at the same absolute speed at different levels of gravity (0.25g-1.0g). In lower gravity, subjects walked with lower duty factors (10 %) and shorter relative stride lengths (16 %). These modest changes in response to the fourfold change in gravity indicate that factors other than gravitational forces are the primary determinants of walking biomechanics.

  1. Toe Walking in Children

    MedlinePlus

    ... generalized disease of nerve and muscle. Children with autism also may walk on their toes or the ... initially walked normally before starting to toe walk. Autism. Toe walking has also been linked to autism, ...

  2. Quantum random walks without walking

    SciTech Connect

    Manouchehri, K.; Wang, J. B.

    2009-12-15

    Quantum random walks have received much interest due to their nonintuitive dynamics, which may hold the key to a new generation of quantum algorithms. What remains a major challenge is a physical realization that is experimentally viable and not limited to special connectivity criteria. We present a scheme for walking on arbitrarily complex graphs, which can be realized using a variety of quantum systems such as a Bose-Einstein condensate trapped inside an optical lattice. This scheme is particularly elegant since the walker is not required to physically step between the nodes; only flipping coins is sufficient.

  3. 10 CFR 431.304 - Uniform test method for the measurement of energy consumption of walk-in coolers and walk-in...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... it is produced in its final chemical form. Foam produced inside of a panel (“foam-in-place”) must be... shall be tested after it is produced in its final chemical form. Foam produced inside of a panel (“foam... set forth in AHRI 1250 and recording the annual energy consumption term in the equation for...

  4. Effect of a 4-week Nordic walking training on the physical fitness and self-assessment of the quality of health of women of the perimenopausal age

    PubMed Central

    Saulicz, Mariola; Saulicz, Edward; Myśliwiec, Andrzej; Wolny, Tomasz; Knapik, Andrzej; Rottermund, Jerzy

    2015-01-01

    Aim of the study To determine the effect of a 4-week Nordic walking training on the physical fitness of women of the perimenopausal age and self-assessment of the quality of their health. Material and methods Eighty-four women between 48 and 58 years of age were included in the study. Half of the group (42) was assigned to the control group and the other half was assigned to the experimental group. In both groups studied, physical fitness was evaluated using a modified Fullerton's test and a quality of life self-assessment SF-36 (Short Form of Health Status Questionnaire). Similar tests were repeated 4 weeks later. In the experimental group, a Nordic walking training was conducted between the two tests. During 4 weeks, 10 training sessions were performed, each session was 60 minutes long, and there was an interval of 2 days between the sessions. Results A 4-week Nordic walking training resulted in a significant improvement (p < 0.001) of physical fitness as demonstrated by an increased strength and flexibility of the upper and lower part of the body and the ability to walk a longer distance during a 6-minute walking test. Women participating in the training also showed a significant improvement in health in terms of both physical health (p < 0.001) and mental health (p < 0.001). Conclusions A 4-week Nordic walking training has a positive effect on the physical fitness of the women in the perimenopausal age. Participation in training contributes also to a clearly higher self-assessment of the quality of health. PMID:26327897

  5. Randomized controlled trial of physical activity, cognition, and walking in multiple sclerosis.

    PubMed

    Sandroff, Brian M; Klaren, Rachel E; Pilutti, Lara A; Dlugonski, Deirdre; Benedict, Ralph H B; Motl, Robert W

    2014-02-01

    The present study adopted a randomized controlled trial design and examined the effect of a physical activity behavioral intervention on cognitive and walking performance among persons with MS who have mild or moderate disability status. A total of 82 MS patients were randomly allocated into intervention or wait-list control conditions. The intervention condition received a theory-based program for increasing physical activity behavior that was delivered via the Internet, and one-on-one video chat sessions with a behavior-change coach. Participants completed self-report measures of physical activity and disability status, and underwent the oral Symbol Digit Modalities Test (SDMT) and 6-minute walk (6MW) test before and after the 6-month period. Analysis using mixed-model ANOVA indicated a significant time × condition × disability group interaction on SDMT scores (p = 0.02, partial-η (2) = 0.08), such that persons with mild disability in the intervention condition demonstrated a clinically meaningful improvement in SDMT scores (~6 point change). There was a further significant time × condition interaction on 6MW distance (p = 0.02, partial-η (2) = 0.07), such that those in the intervention condition demonstrated an increase in 6MW distance relative to those in the control group. The current study supports physical activity as a promising tool for managing cognitive impairment and impaired walking performance in persons with MS, and suggests that physical activity might have specific effects on cognition and non-specific effects on walking performance in this population.

  6. Using short vignettes to disentangle perceived capability from motivation: a test using walking and resistance training behaviors.

    PubMed

    Rhodes, Ryan E; Williams, David M; Mistry, Chetan D

    2016-07-01

    Self-efficacy is arguably the strongest correlate of physical activity, yet some researchers suggest this is because the construct confounds ability with motivation. We examine a more circumscribed construct, called perceived capability (PC), meant to measure ability but not motivation and propose that the construct will not be related to unskilled physical activities but may be linked to skilled behaviors. The purpose of this paper was to examine whether a PC construct can be stripped of motivation using a vignette approach in both walking and resistance training behaviors. Participants were a random sample of 248 university students, who were then randomly assigned to either answer resistance training or walking behavior questions. Both groups completed a PC measure and reasons for their answer before and after reading a vignette that clarified the phrasing of capability to a literal use of the term. PC was significantly (p < .01) higher post- compared to pre-vignette and the differences were greater (p < .01) for walking than for resistance training. PC had significantly (p < .01) smaller correlations with intention and self-reported behavior post-disambiguation, which resulted in a null relationship with walking but a small correlation with resistance training behavior. When PC was combined with intention to predict behavior, however, there was no significant (p > .05) difference in the amount of variance explained pre- to post-vignette. Thought listing showed that participants did not report capability barriers to walking and over half of the sample construed capability as motivation/other priorities pre-vignette. The findings support use of a vignette approach for researchers who wish to disentangle the assessment of PC from motivation while creating no overall loss in explained variance of physical activity.

  7. Reliability and validity of heart rate variability threshold assessment during an incremental shuttle-walk test in middle-aged and older adults

    PubMed Central

    Dourado, V.Z.; Guerra, R.L.F.

    2013-01-01

    Studies on the assessment of heart rate variability threshold (HRVT) during walking are scarce. We determined the reliability and validity of HRVT assessment during the incremental shuttle walk test (ISWT) in healthy subjects. Thirty-one participants aged 57 ± 9 years (17 females) performed 3 ISWTs. During the 1st and 2nd ISWTs, instantaneous heart rate variability was calculated every 30 s and HRVT was measured. Walking velocity at HRVT in these tests (WV-HRVT1 and WV-HRVT2) was registered. During the 3rd ISWT, physiological responses were assessed. The ventilatory equivalents were used to determine ventilatory threshold (VT) and the WV at VT (WV-VT) was recorded. The difference between WV-HRVT1 and WV-HRVT2 was not statistically significant (median and interquartile range = 4.8; 4.8 to 5.4 vs 4.8; 4.2 to 5.4 km/h); the correlation between WV-HRVT1 and WV-HRVT2 was significant (r = 0.84); the intraclass correlation coefficient was high (0.92; 0.82 to 0.96), and the agreement was acceptable (-0.08 km/h; -0.92 to 0.87). The difference between WV-VT and WV-HRVT2 was not statistically significant (4.8; 4.8 to 5.4 vs 4.8; 4.2 to 5.4 km/h) and the agreement was acceptable (0.04 km/h; -1.28 to 1.36). HRVT assessment during walking is a reliable measure and permits the estimation of VT in adults. We suggest the use of the ISWT for the assessment of exercise capacity in middle-aged and older adults. PMID:23369974

  8. Physiological responses to maximal exercise testing and the modified incremental shuttle walk test in adults after thermal injury: a pilot study.

    PubMed

    Stockton, Kellie Anne; Davis, Mark John; Brown, Michael Graeme; Boots, Robert; Paratz, Jennifer Davida

    2012-01-01

    The ongoing hypermetabolic response associated with burn injury contributes significantly to loss of function, morbidity, and mortality. Exercise is strongly recommended to assist recovery and overall functional outcome. To date, there have been limited studies investigating the validity and practicality of both maximal laboratory and field tests in adult burns survivors. The objective of this study was to determine the metabolic and ventilatory response to cardiopulmonary maximal exercise testing (CPET) and the modified shuttle walk test (MSWT) in adult burns patients. Fifteen people (13 male) with a mean TBSA of 38.5% (16.0%) underwent both MSWT and CPET within a 5-day period in random order. The majority of participants demonstrated a normal response to CPET. Two participants with a history of inhalation burns demonstrated a respiratory limitation to exercise with desaturation (91 and 89%) at the end of the CPET, which returned to normal within 2 minutes after exercise. The correlation between VO(2peak) as measured via CPET and distance as measured in MSWT was 0.7. Mean results measured in MSWT for maximal heart rate and perceived exertion scores were lower than those achieved with CPET results: 91 and 88%, respectively. There were no adverse events during both the MSWT and CPET. This study demonstrates that after burn injury, CPET and MSWT can be performed safely in the majority of patients early in the postdischarge rehabilitation period. MSWT is likely to be submaximal at 80 to 90% of CPET results but is easy to replicate and cost-effective, thus a viable mechanism for monitoring aerobic capacity.

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

    PubMed

    An, SeungHeon; Lee, YunBok; Shin, HyeonHui; Lee, GyuChang

    2015-12-01

    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.

  10. Physical and functional follow-up of tuberculosis patients in initial intensive phase of treatment in Cameroon using the 6-min walk test

    PubMed Central

    Guessogo, Wiliam R.; Mandengue, Samuel H.; Assomo Ndemba, Peguy B.; Medjo, Ubald Olinga; Minye, Edmond Ebal; Ahmaidi, Said; Temfemo, Abdou

    2016-01-01

    This study aimed to evaluate functional capacities of Cameroonian tuberculosis (TB) patients in initial intensive phase of treatment using the 6-min walk test (6MWT) and to compare them to an age-matched healthy group. Twenty-eight TB patients newly diagnosed and 19 healthy age-matched peoples participated in the study. Performance parameters were determined using the 6MWT. Anthropometric and cardiorespiratory parameters were measured at baseline and after 6MWT. Two months later, TB patients were submitted to the same evaluation. We found significant differences in anthropometric parameters between the two groups. The baseline cardiorespiratory parameters and performance characteristics of TB patients were lower than control group (571.7±121.0 m vs 841.6±53.0 m, P<0.0001 for 6-min walk distance (6MWD) and 18.1±2.8 mL/kg/min vs 24.3±1.2 mL/kg/min, P<0.001 for mean VO2 peak (peak oxygen consumption). Two months after, significant improvements were noted in anthropometric, cardiorespiratory and performance parameters except for bone mass and FEV1/FEV6 (forced expiratory volumes in 1 second/6 seconds) ratio. Significant correlations were found between the 2-min walked distance (P<0.0001, r=0.95), 4-min walked distance (P<0.0001, r=0.97) and 6MWD. In conclusion, TB patients have impaired physical functional capacity but they improved after 2 months of treatment. 6MWT can be a useful tool in the assessment of physical parameters and cardiorespiratory functional capacity rehabilitation of TB patients during the treatment. PMID:27656631

  11. Physical and functional follow-up of tuberculosis patients in initial intensive phase of treatment in Cameroon using the 6-min walk test.

    PubMed

    Guessogo, Wiliam R; Mandengue, Samuel H; Assomo Ndemba, Peguy B; Medjo, Ubald Olinga; Minye, Edmond Ebal; Ahmaidi, Said; Temfemo, Abdou

    2016-08-01

    This study aimed to evaluate functional capacities of Cameroonian tuberculosis (TB) patients in initial intensive phase of treatment using the 6-min walk test (6MWT) and to compare them to an age-matched healthy group. Twenty-eight TB patients newly diagnosed and 19 healthy age-matched peoples participated in the study. Performance parameters were determined using the 6MWT. Anthropometric and cardiorespiratory parameters were measured at baseline and after 6MWT. Two months later, TB patients were submitted to the same evaluation. We found significant differences in anthropometric parameters between the two groups. The baseline cardiorespiratory parameters and performance characteristics of TB patients were lower than control group (571.7±121.0 m vs 841.6±53.0 m, P<0.0001 for 6-min walk distance (6MWD) and 18.1±2.8 mL/kg/min vs 24.3±1.2 mL/kg/min, P<0.001 for mean VO2 peak (peak oxygen consumption). Two months after, significant improvements were noted in anthropometric, cardiorespiratory and performance parameters except for bone mass and FEV1/FEV6 (forced expiratory volumes in 1 second/6 seconds) ratio. Significant correlations were found between the 2-min walked distance (P<0.0001, r=0.95), 4-min walked distance (P<0.0001, r=0.97) and 6MWD. In conclusion, TB patients have impaired physical functional capacity but they improved after 2 months of treatment. 6MWT can be a useful tool in the assessment of physical parameters and cardiorespiratory functional capacity rehabilitation of TB patients during the treatment.

  12. Prognostic value of variables derived from the six-minute walk test in patients with COPD: Results from the ECLIPSE study.

    PubMed

    Andrianopoulos, Vasileios; Wouters, Emiel F M; Pinto-Plata, Victor M; Vanfleteren, Lowie E G W; Bakke, Per S; Franssen, Frits M E; Agusti, Alvar; MacNee, William; Rennard, Stephen I; Tal-Singer, Ruth; Vogiatzis, Ioannis; Vestbo, Jørgen; Celli, Bartolome R; Spruit, Martijn A

    2015-09-01

    In addition to the six-min walk distance (6 MWD), other six-min walk test (6 MWT) derived variables, such as mean walk-speed (6MWSpeed), 6-min walk-work (6 MWW), distance-saturation product (DSP), exercise-induced oxygen desaturation (EID), and unintended stops may be useful for the prediction of mortality and hospitalization in patients with chronic obstructive pulmonary disease (COPD). We studied the association between 6 MWT-derived variables and mortality as well as hospitalization in COPD patients and compared it with the BODE index. A three-year prospective study (ECLIPSE) to evaluate the prognostic value of 6 MWT-derived variables in 2010 COPD patients. Cox's proportional-hazard regressions were performed to estimate 3-year mortality and hospitalization. During the follow-up, 193 subjects died and 622 were hospitalized. An adjusted Cox's regression model of hazard ratio [HR] for impaired 6 MWT-derived variables was significant referring to: mortality (6 MWD ≤334 m [2.30], 6MWSpeed ≤0.9 m/sec [2.15], 6 MWW ≤20000 m kg [2.17], DSP ≤290 m% [2.70], EID ≤88% [1.75], unintended stops [1.99]; and hospitalization (6 MWW ≤27000 m kg [1.23], EID ≤88% [1.25], BODE index ≥3 points [1.40]; all p ≤ 0.05). The 6 MWT-derived variables have an additional predictive value of mortality in patients with COPD. The 6 MWW, EID and the BODE index refine the prognosis of hospitalization.

  13. Pulse pressure is associated with walking impairment in multiple sclerosis.

    PubMed

    Heffernan, Kevin S; Ranadive, Sushant; Weikert, Madeline; Lane, Abbi; Yan, Huiman; Fernhall, Bo; Motl, Robert W

    2011-10-15

    Persons with multiple sclerosis (MS) have reduced gait performance and this is associated with disability and disease progression. The current study sought to test the hypothesis that higher central (aortic and carotid) and peripheral (brachial) pulse pressure (PP), manifestations of ventricular-vascular uncoupling related to increased arterial stiffness and pressure from wave reflections, would be associated with reduced gait performance in persons with MS. Participants consisted of 33 individuals with MS and 33 age/sex matched controls. Central blood pressure (BP) was assessed via applanation tonometry. Brachial BP was measured using an automated oscillometric cuff. PP was defined as systolic BP--diastolic BP. Gait performance was measured as 6-minute walk (6 MW) distance. Within the sample with MS, the 6 MW distance was significantly associated with brachial (r = -.49, p<.005), aortic (r = -.52, p<.001), and carotid (r = -.57, p<.001) pulse pressure. There was no association between any PP measure and 6 MW distance in controls (p>0.05 for all). In conclusion, PP is a predictor of gait performance in persons with MS. These findings suggest that vascular senescence and altered ventricular-vascular coupling may contribute, in part, to the deterioration of physical function in persons with MS.

  14. The effects of gravity on human walking: a new test of the dynamic similarity hypothesis using a predictive model.

    PubMed

    Raichlen, David A

    2008-09-01

    The dynamic similarity hypothesis (DSH) suggests that differences in animal locomotor biomechanics are due mostly to differences in size. According to the DSH, when the ratios of inertial to gravitational forces are equal between two animals that differ in size [e.g. at equal Froude numbers, where Froude = velocity2/(gravity x hip height)], their movements can be made similar by multiplying all time durations by one constant, all forces by a second constant and all linear distances by a third constant. The DSH has been generally supported by numerous comparative studies showing that as inertial forces differ (i.e. differences in the centripetal force acting on the animal due to variation in hip heights), animals walk with dynamic similarity. However, humans walking in simulated reduced gravity do not walk with dynamically similar kinematics. The simulated gravity experiments did not completely account for the effects of gravity on all body segments, and the importance of gravity in the DSH requires further examination. This study uses a kinematic model to predict the effects of gravity on human locomotion, taking into account both the effects of gravitational forces on the upper body and on the limbs. Results show that dynamic similarity is maintained in altered gravitational environments. Thus, the DSH does account for differences in the inertial forces governing locomotion (e.g. differences in hip height) as well as differences in the gravitational forces governing locomotion.

  15. The walking robot project

    NASA Technical Reports Server (NTRS)

    Williams, P.; Sagraniching, E.; Bennett, M.; Singh, R.

    1991-01-01

    A walking robot was designed, analyzed, and tested as an intelligent, mobile, and a terrain adaptive system. The robot's design was an application of existing technologies. The design of the six legs modified and combines well understood mechanisms and was optimized for performance, flexibility, and simplicity. The body design incorporated two tripods for walking stability and ease of turning. The electrical hardware design used modularity and distributed processing to drive the motors. The software design used feedback to coordinate the system and simple keystrokes to give commands. The walking machine can be easily adapted to hostile environments such as high radiation zones and alien terrain. The primary goal of the leg design was to create a leg capable of supporting a robot's body and electrical hardware while walking or performing desired tasks, namely those required for planetary exploration. The leg designers intent was to study the maximum amount of flexibility and maneuverability achievable by the simplest and lightest leg design. The main constraints for the leg design were leg kinematics, ease of assembly, degrees of freedom, number of motors, overall size, and weight.

  16. Visual control of walking velocity.

    PubMed

    François, Matthieu; Morice, Antoine H P; Bootsma, Reinoud J; Montagne, Gilles

    2011-06-01

    Even if optical correlates of self-motion velocity have already been identified, their contribution to the control of displacement velocity remains to be established. In this study, we used a virtual reality set-up coupled to a treadmill to test the role of both Global Optic Flow Rate (GOFR) and Edge Rate (ER) in the regulation of walking velocity. Participants were required to walk at a constant velocity, corresponding to their preferred walking velocity, while eye height and texture density were manipulated. This manipulation perturbed the natural relationship between the actual walking velocity and its optical specification by GOFR and ER, respectively. Results revealed that both these sources of information are indeed used by participants to control walking speed, as demonstrated by a slowing down of actual walking velocity when the optical specification of velocity by either GOFR or ER gives rise to an overestimation of actual velocity, and vice versa. Gait analyses showed that these walking velocity adjustments result from simultaneous adaptations in both step length and step duration. The role of visual information in the control of self-motion velocity is discussed in relation with other factors.

  17. Imaging Shallow Aquitard Breaches with P waves: Results from a Walk-away test and a Reflection Survey at two Sites in Memphis, Tennessee, USA

    NASA Astrophysics Data System (ADS)

    Ge, J.; Magnani, M.; Waldron, B. A.

    2006-12-01

    We present the results of two seismic reflection experiments conducted in the Great Memphis area in April and July 2006. The two experiments consisted in a walk-away test and in the acquisition of a 1 km seismic reflection profile. The acquisition of the seismic data is part of a larger effort aimed at imaging the lateral continuity of the Upper Claiborne confining clay that separates the Memphis aquifer, the region's primary drinking water source, from the upper unconfined aquifer and protects the drinking aquifer from exposure to potential contamination. During the walk-away test, four P-wave sources, a 7.5 kg sledge hammer, a 20 kg weight drop, a 12-gauge Buffalo gun, and a Minivibe source were tested at two sites with the goal of selecting the best P-wave seismic source and acquisition parameters for shallow reflection surveys. Boreholes nearby both sites encountered the Upper Claiborne unit at a depth ranging from 10 m to 40 m. One site is located within a 100-meter length of road median that can be considered an urban environment. The second site is located at Shelby Farms within the City of Memphis yet reflects a rural setting with minimal noise and no subsurface infrastructure. Performing identical walk-away tests at both sites, the results indicate that the energy source selection is site dependent. At the urban site, the energy generated by the weight drop source is more coherent and can be interpreted with more confidence on the recorded data. However the Shelby Farms site the 12-gauge shotgun produced the strongest recorded energy, the highest dominant frequency and the broadest frequency band (6- 110 Hz). Strong attenuations are observed at both sites with a much higher attenuation in the urban road median site, where the near surface materials consisted of gravels, sands, clays, and pebbles. For both sites, surface waves and refractions dominate the seismic recordings. Filtering and gain of the data revealed the presence of shallow reflections related

  18. Self-efficacy mediates the relationship between balance/walking performance, activity, and participation after stroke

    PubMed Central

    Moore, Meghan F; Pohlig, Ryan; Reisman, Darcy

    2015-01-01

    Background Many outcome measures (OM) that assess individuals’ ability or beliefs in their ability to perform tasks exist to evaluate activity and participation after stroke; however, the relationship between various OM and activity/participation is unclear. Objective The purpose of this study was to explore the relationships between different OM and activity and participation in people after stroke. Methods 59 subjects post-stroke participated in an assessment including self-selected walking speed, 6 minute walk test, Timed “Up and Go” Test, Berg Balance Scale, Functional Gait Assessment, Walk 12, and Activity-specific Balance Confidence Scale. Step Activity Monitoring (SAM) was used as a measure of activity and Stroke Impact Scale-Participation (SIS-P) as a measure of participation. Exploratory Factor Analysis was performed including all measures except SAM and SIS-P. Two factors were extracted and termed performance based (PB) and self-efficacy (SE). A Path Analysis assessed the role of SE as a mediator in the relationships of PB and SAM/SIS-P. Results In the path analysis, PB significantly predicts SE (p < 0.001, b=0.44), but not SAM or SIS-P (p > 0.05, b=0.25 and b=0.11 respectively). SE significantly predicts both SAM and SIS-P (p < 0.001, b=0.46 and b=0.59 respectively). The Indirect Effects of PB on SAM and SIS-P were significant (p < 0.001; b=0.20 and b=0.26 respectively). Conclusion These results suggest that SE mediates the relationship between PB and activity and participation after stroke, reinforcing that improving activity and participation is more complicated than only targeting performance. Clinicians should administer SE and PB measures to determine the most accurate view of patients after stroke and seek to improve SE through interventions. PMID:26653764

  19. Correlation between the Yale Physical Activity Survey (YPAS) and a submaximal performance-based test: a study in a population of elderly Spanish women.

    PubMed

    Martín, Vicente; Ayán, Carlos; Molina, Antonio J; Alvarez, María J; Varela, Silvia; Cancela, José M

    2012-01-01

    The aim of this study is to research the degree of correlation between the Spanish version of the questionnaire YPAS and the 6-minute walking test (6MWT) in women over 60. In addition, the authors analyzed the relationship between the variables age and body mass index (BMI) and the walked distance. The study was carried out with 44 elderly women (68.1 ± 5.4 years) who filled in the questionnaire and immediately afterwards performed the 6MWT. Total time and energy expenditure (EE) values obtained in the questionnaire are significantly correlated with the 6MWT (p=0.02; p=0.01, respectively), while BMI and age showed an inverse association (r=-0.433; r=-0.318, respectively) with the walked distance. The Spanish version of YPAS is beginning to be considered as a valid and useful tool for habitual physical activity (PA) measurement and can be used among elderly Spanish speaking women.

  20. The Effects of Varying Ankle Foot Orthosis Stiffness on Gait in Children with Spastic Cerebral Palsy Who Walk with Excessive Knee Flexion

    PubMed Central

    Kerkum, Yvette L.; Buizer, Annemieke I.; van den Noort, Josien C.; Becher, Jules G.; Harlaar, Jaap; Brehm, Merel-Anne

    2015-01-01

    Introduction Rigid Ankle-Foot Orthoses (AFOs) are commonly prescribed to counteract excessive knee flexion during the stance phase of gait in children with cerebral palsy (CP). While rigid AFOs may normalize knee kinematics and kinetics effectively, it has the disadvantage of impeding push-off power. A spring-like AFO may enhance push-off power, which may come at the cost of reducing the knee flexion less effectively. Optimizing this trade-off between enhancing push-off power and normalizing knee flexion in stance is expected to maximize gait efficiency. This study investigated the effects of varying AFO stiffness on gait biomechanics and efficiency in children with CP who walk with excessive knee flexion in stance. Fifteen children with spastic CP (11 boys, 10±2 years) were prescribed with a ventral shell spring-hinged AFO (vAFO). The hinge was set into a rigid, or spring-like setting, using both a stiff and flexible performance. At baseline (i.e. shoes-only) and for each vAFO, a 3D-gait analysis and 6-minute walk test with breath-gas analysis were performed at comfortable speed. Lower limb joint kinematics and kinetics were calculated. From the 6-minute walk test, walking speed and the net energy cost were determined. A generalized estimation equation (p<0.05) was used to analyze the effects of different conditions. Compared to shoes-only, all vAFOs improved the knee angle and net moment similarly. Ankle power generation and work were preserved only by the spring-like vAFOs. All vAFOs decreased the net energy cost compared to shoes-only, but no differences were found between vAFOs, showing that the effects of spring-like vAFOs to promote push-off power did not lead to greater reductions in walking energy cost. These findings suggest that, in this specific group of children with spastic CP, the vAFO stiffness that maximizes gait efficiency is primarily determined by its effect on knee kinematics and kinetics rather than by its effect on push-off power. Trial

  1. Effects of underwater treadmill training on leg strength, balance, and walking performance in adults with incomplete spinal cord injury

    PubMed Central

    Stevens, Sandra L.; Caputo, Jennifer L.; Fuller, Dana K.; Morgan, Don W.

    2015-01-01

    Objective To document the effects of underwater treadmill training (UTT) on leg strength, balance, and walking performance in adults with incomplete spinal cord injury (iSCI). Design Pre-test and post-test design. Setting Exercise physiology laboratory. Participants Adult volunteers with iSCI (n = 11). Intervention Participants completed 8 weeks (3 × /week) of UTT. Each training session consisted of three walks performed at a personalized speed, with adequate rest between walks. Body weight support remained constant for each participant and ranged from 29 to 47% of land body weight. Increases in walking speed and duration were staggered and imposed in a gradual and systematic fashion. Outcome measures Lower-extremity strength (LS), balance (BL), preferred and rapid walking speeds (PWS and RWS), 6-minute walk distance (6MWD), and daily step activity (DSA). Results Significant (P < 0.05) increases were observed in LS (13.1 ± 3.1 to 20.6 ± 5.1 N·kg−1), BL (23 ± 11 to 32 ± 13), PWS (0.41 ± 0.27 to 0.55 ± 0.28 m·s−1), RWS (0.44 ± 0.31 to 0.71 ± 0.40 m·s−1), 6MWD (97 ± 80 to 177 ± 122 m), and DSA (593 ± 782 to 1310 ± 1258 steps) following UTT. Conclusion Physical function and walking ability were improved in adults with iSCI following a structured program of UTT featuring individualized levels of body weight support and carefully staged increases in speed and duration. From a clinical perspective, these findings highlight the potential of UTT in persons with physical disabilities and diseases that would benefit from weight-supported exercise. PMID:24969269

  2. The Walk Poem.

    ERIC Educational Resources Information Center

    Padgett, Ron

    2000-01-01

    Discusses the long history of writing poems about a walk, noting many titles. Notes four basic types of walk poems and includes one by American poet Bill Zavatksy, called "Class Walk With Notebooks After Storm." Offers numerous brief ideas for both the writing and the form of walk poems. (SR)

  3. Fire-Walking

    ERIC Educational Resources Information Center

    Willey, David

    2010-01-01

    This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

  4. Clinical effectiveness and safety of powered exoskeleton-assisted walking in patients with spinal cord injury: systematic review with meta-analysis

    PubMed Central

    Miller, Larry E; Zimmermann, Angela K; Herbert, William G

    2016-01-01

    Background Powered exoskeletons are designed to safely facilitate ambulation in patients with spinal cord injury (SCI). We conducted the first meta-analysis of the available published research on the clinical effectiveness and safety of powered exoskeletons in SCI patients. Methods MEDLINE and EMBASE databases were searched for studies of powered exoskeleton-assisted walking in patients with SCI. Main outcomes were analyzed using fixed and random effects meta-analysis models. Results A total of 14 studies (eight ReWalk™, three Ekso™, two Indego®, and one unspecified exoskeleton) representing 111 patients were included in the analysis. Training programs were typically conducted three times per week, 60–120 minutes per session, for 1–24 weeks. Ten studies utilized flat indoor surfaces for training and four studies incorporated complex training, including walking outdoors, navigating obstacles, climbing and descending stairs, and performing activities of daily living. Following the exoskeleton training program, 76% of patients were able to ambulate with no physical assistance. The weighted mean distance for the 6-minute walk test was 98 m. The physiologic demand of powered exoskeleton-assisted walking was 3.3 metabolic equivalents and rating of perceived exertion was 10 on the Borg 6–20 scale, comparable to self-reported exertion of an able-bodied person walking at 3 miles per hour. Improvements in spasticity and bowel movement regularity were reported in 38% and 61% of patients, respectively. No serious adverse events occurred. The incidence of fall at any time during training was 4.4%, all occurring while tethered using a first-generation exoskeleton and none resulting in injury. The incidence of bone fracture during training was 3.4%. These risks have since been mitigated with newer generation exoskeletons and refinements to patient eligibility criteria. Conclusion Powered exoskeletons allow patients with SCI to safely ambulate in real-world settings at

  5. A combined exercise model for improving muscle strength, balance, walking distance, and motor agility in multiple sclerosis patients: A randomized clinical trial

    PubMed Central

    Sangelaji, Bahram; Kordi, Mohammadreza; Banihashemi, Farzaneh; Nabavi, Seyed Massood; Khodadadeh, Sara; Dastoorpoor, Maryam

    2016-01-01

    Background: Multiple sclerosis (MS) is a neurological disease with a variety of signs and symptoms. Exercise therapy has been shown to improve physical functions in MS. However, questions about an optimal exercise therapy remain. In this regard, we suggest a combined exercise therapy including aerobic and resistance exercises for MS patients. The study is designed to observe, test and compare the effects of proposed combined exercises on strength, balance, agility, fatigue, speed, and walking distance in people with mild to moderate MS [0 < expanded disability status scale (EDSS) < 5]. Methods: A total of 40 people with relapse-remitting MS (16 male, 0 < EDSS < 5) were randomized into one of the four groups (3 intervention and one control). The intervention consisted of various combinations of aerobic and resistance exercises with different repetition rates. Pre- and post-intervention scores of fatigue severity scale (FSS), timed up and go (TUG) test, 6-minute walk test (6MWT), 10- and 20-MWT, Berg balance scale (BBS), and one repetition maximum (1RM) test were recorded and analyzed. Results: For most tests, post-intervention values of the group 1, with 3-aerobic and 1-resistance exercises, were significantly higher compared to control group (P < 0.050). However, no significant progression was observed in the other two intervention groups. Conclusion: A combination of three aerobic exercises with one resistance exercise may result in improved balance, locomotion, and endurance in MS patients. PMID:27648171

  6. The Effect of Treadmill Exercise on Gait Efficiency During Overground Walking in Adults With Cerebral Palsy

    PubMed Central

    Kim, On-Yoo; Shin, Yoon-Kyum; Yoon, Young Kwon; Ko, Eu Jeong

    2015-01-01

    Objective To investigate the effect of treadmill walking exercise as a treatment method to improve gait efficiency in adults with cerebral palsy (CP) and to determine gait efficiency during overground walking after the treadmill walking exercise. Methods Fourteen adults with CP were recruited in the experimental group of treadmill walking exercise. A control group of 7 adults with CP who attended conventional physical therapy were also recruited. The treadmill walking exercise protocol consisted of 3-5 training sessions per week for 1-2 months (total 20 sessions). Gait distance, velocity, VO2, VCO2, O2 rate (mL/kg·min), and O2 cost (mL/kg·m) were assessed at the beginning and at the end of the treadmill walking exercise. The parameters were measured by KB1-C oximeter. Results After the treadmill walking exercise, gait distance during overground walking up to 6 minutes significantly increased from 151.29±91.79 to 193.93±79.01 m, and gait velocity increased from 28.09±14.29 to 33.49±12.69 m/min (p<0.05). Energy efficiency evaluated by O2 cost during overground walking significantly improved from 0.56±0.36 to 0.41±0.18 mL/kg·m (p<0.05), whereas O2 rate did not improve significantly after the treadmill walking exercise. On the other hand, gait velocity and O2 cost during overground walking were not significantly changed in the control group. Conclusion Treadmill walking exercise improved the gait efficiency by decreased energy expenditure during overground walking in adults with CP. Therefore, treadmill walking exercise can be an important method for gait training in adults with CP who have higher energy expenditure. PMID:25750868

  7. The Not-so-Random Drunkard's Walk

    ERIC Educational Resources Information Center

    Ehrhardt, George

    2013-01-01

    This dataset contains the results of a quasi-experiment, testing Karl Pearson's "drunkard's walk" analogy for an abstract random walk. Inspired by the alternate hypothesis that drunkards stumble to the side of their dominant hand, it includes data on intoxicated test subjects walking a 10' line. Variables include: the…

  8. Cell phones change the way we walk.

    PubMed

    Lamberg, Eric M; Muratori, Lisa M

    2012-04-01

    Cell phone use among pedestrians leads to increased cognitive distraction, reduced situation awareness and increases in unsafe behavior. Performing a dual-task, such as talking or texting with a cell phone while walking, may interfere with working memory and result in walking errors. At baseline, thirty-three participants visually located a target 8m ahead; then vision was occluded and they were instructed to walk to the remembered target. One week later participants were assigned to either walk, walk while talking on a cell phone, or walk while texting on a cell phone toward the target with vision occluded. Duration and final location of the heel were noted. Linear distance traveled, lateral angular deviation from the start line, and gait velocity were derived. Changes from baseline to testing were analyzed with paired t-tests. Participants engaged in cell phone use presented with significant reductions in gait velocity (texting: 33% reduction, p=0.01; talking: 16% reduction, p=0.02). Moreover, participants who were texting while walking demonstrated a 61% increase in lateral deviation (p=0.04) and 13% increase in linear distance traveled (p=0.03). These results suggest that the dual-task of walking while using a cell phone impacts executive function and working memory and influences gait to such a degree that it may compromise safety. Importantly, comparison of the two cell phone conditions demonstrates texting creates a significantly greater interference effect on walking than talking on a cell phone.

  9. A comparison of the effects of swimming and walking on body weight, fat distribution, lipids, glucose, and insulin in older women--the Sedentary Women Exercise Adherence Trial 2.

    PubMed

    Cox, Kay L; Burke, Valerie; Beilin, Lawrence J; Puddey, Ian B

    2010-11-01

    All types of aerobic exercise are assumed to affect cardiovascular risk similarly. There are few studies of swimming, but complex responses to water-based exercise suggest its potential for differential effects. The aim of the study was to compare the effects of swimming and walking on fitness, body weight, lipids, glucose, and insulin in older women. Sedentary women aged 50 to 70 years (N = 116), randomly assigned to swimming or walking plus usual care or a behavioral intervention, completed 3 sessions per week of moderate-intensity exercise, supervised for 6 months then unsupervised for 6 months. After 6 months, 1.6-km walk time decreased in walkers and swimmers, with greater improvement in walkers (1.0 vs 0.6 minute, P = .001). In swimmers, but not walkers, distance swum in 12 minutes increased (78.1 vs -2.2 m, P = .021). Waist and hip circumferences (80.8 vs 83.1 cm and 101.8 vs 102.4 cm; P = .023 and P = .042, respectively) and insulin area under the curve (oral glucose tolerance test) (5128 vs 5623 μU/[L 120 min], P < .05) were lower with swimming. Lipids did not differ between groups. At 12 months, fitness was maintained. Relative to walking, swimming reduced body weight by (1.1 kg, P = .039) and resulted in lower total and low-density lipoprotein cholesterol (0.3 and 0.2 mmol/L; P = .040 and P = .049, respectively). The magnitude of the difference in the reduction of insulin area under the curve between swimming and walking was greater at 12 months; however, the significance was attenuated (4677 vs 5240 μU/[L 120 min], P = .052). Compared with walking, swimming improved body weight, body fat distribution, and insulin in the short term and, in the longer term, body weight and lipid measures. These findings suggest that the type of exercise can influence health benefits.

  10. On alternating quantum walks

    NASA Astrophysics Data System (ADS)

    Rousseva, Jenia; Kovchegov, Yevgeniy

    2017-03-01

    We study an inhomogeneous quantum walk on a line that evolves according to alternating coins, each a rotation matrix. For the quantum walk with the coin alternating between clockwise and counterclockwise rotations by the same angle, we derive a closed form solution for the propagation of probabilities, and provide its asymptotic approximation via the method of stationary phase. Finally, we observe that for a x03c0;/4 angle, this alternating rotation walk will replicate the renown Hadamard walk.

  11. Walk This Way

    ERIC Educational Resources Information Center

    Mason, Nick

    2007-01-01

    A generation ago, it was part of growing up for all kids when they biked or walked to school. But in the last 30 years, heavier traffic, wider roads and more dangerous intersections have made it riskier for students walking or pedaling. Today, fewer than 15 percent of kids bike or walk to school compared with more than 50 percent in 1969. In the…

  12. Walking Wellness. Student Workbook.

    ERIC Educational Resources Information Center

    Sweetgall, Robert; Neeves, Robert

    This comprehensive student text and workbook, for grades four through eight, contains 16 workshop units focusing on walking field trips, aerobic pacing concepts, walking techniques, nutrition, weight control and healthy life-style planning. Co-ordinated homework assignments are included. The appendixes include 10 tips for walking, a calorie chart,…

  13. Quantum walk computation

    SciTech Connect

    Kendon, Viv

    2014-12-04

    Quantum versions of random walks have diverse applications that are motivating experimental implementations as well as theoretical studies. Recent results showing quantum walks are “universal for quantum computation” relate to algorithms, to be run on quantum computers. We consider whether an experimental implementation of a quantum walk could provide useful computation before we have a universal quantum computer.

  14. Sex-specific predictors of improved walking with step-monitored, home-based exercise in peripheral artery disease.

    PubMed

    Gardner, Andrew W; Parker, Donald E; Montgomery, Polly S

    2015-10-01

    The aim of this study was to determine whether baseline clinical characteristics and the duration and intensity of ambulation during our step-monitored home-based exercise program were predictive of changes in ambulatory outcomes at completion of the program in symptomatic patients with peripheral artery disease (PAD). Twenty-two men (ankle-brachial index (ABI) = 0.71 ± 0.19) and 24 women (ABI = 0.66 ± 0.23) completed the home exercise program, consisting of intermittent walking to mild-to-moderate claudication pain for 3 months. Ambulatory outcome measures were peak walking time (PWT) and claudication onset time (COT) during a treadmill test, and the distance recorded during a 6-minute walk distance test (6MWD). Men experienced significant increases (p<0.01) in COT, PWT, and 6MWD following the home exercise program, and women had significant increases in 6MWD (p<0.01) and PWT (p<0.05). In women, average exercise cadence during the home exercise sessions was the only predictor that entered the model for change in COT (p=0.082), and was the first predictor in the model for change in PWT (p=0.029) and 6MWD (p=0.006). In men, the ABI was the only predictor that entered the model for change in 6MWD (p=0.002), and ABI was a predictor along with metabolic syndrome in the model for change in COT (p=0.003). No variables entered the model for change in PWT. Faster ambulatory cadence during the step-monitored home-based exercise program may predict greater improvements in ambulatory function in women, whereas having less severe PAD and comorbid burden at baseline may predict greater improvements in ambulatory function in men. ClinicalTrials.gov Identifier: NCT00618670.

  15. Are 30 minutes of rest between two incremental shuttle walking tests enough for cardiovascular variables and perceived exertion to return to baseline values?

    PubMed Central

    Ribeiro, Laís R. G.; Mesquita, Rafael B.; Vidotto, Laís S.; Merli, Myriam F.; Carvalho, Débora R.; de Castro, Larissa A.; Probst, Vanessa S.

    2015-01-01

    Objective: To verify whether 30 minutes of rest between two incremental shuttle walking tests (ISWT) are enough for cardiovascular variables and perceived exertion to return to baseline values in healthy subjects in a broad age range. Method: The maximal exercise capacity of 334 apparently healthy subjects (age ≥18) was evaluated using the ISWT. The test was performed twice with 30 minutes of rest in between. Heart rate (HR), arterial blood pressure (ABP), dyspnea, and leg fatigue were evaluated before and after each test. Subjects were allocated to 6 groups according to their age: G1: 18-29 years; G2: 30-39 years; G3: 40-49 years; G4: 50-59 years; G5: 60-69 years and G6: ≥70 years. Results: All groups had a good performance in the ISWT (median >90% of the predicted distance). The initial HR (HRi) of the second ISWT was higher than the first ISWT in the total sample (p<0.0001), as well as in all groups (p<0.0001). No difference was observed in the behavior of ABP (systolic and diastolic) and dyspnea between the two tests, but this difference occurred for leg fatigue (greater before the second ISWT) in G1 (p<0.05). Most subjects (58%) performed better in the second test. Conclusion: 30 minutes of rest between two ISWTs are not enough for all cardiovascular variables and perceived exertion to return to baseline values. However, this period appears to be sufficient for blood pressure and performance to recover in most subjects. PMID:25789556

  16. 76 FR 65362 - Energy Conservation Program: Compliance Date Regarding the Test Procedures for Walk-In Coolers...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-21

    ... test procedures will be mandatory for making representations of energy usage or energy efficiency... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY 10 CFR Parts 429 and 431 RIN 1904-AC58 Energy Conservation Program: Compliance Date Regarding the...

  17. 76 FR 48745 - Energy Conservation Program: Compliance Date Regarding the Test Procedures for Walk-In Coolers...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-09

    ... final rule stated that the test procedures will be mandatory for making representations of energy usage... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY 10 CFR Parts 429 and 431 RIN 1904-AC58 Energy Conservation Program: Compliance Date Regarding the...

  18. Walk Score®

    PubMed Central

    Brown, Scott C.; Pantin, Hilda; Lombard, Joanna; Toro, Matthew; Huang, Shi; Plater-Zyberk, Elizabeth; Perrino, Tatiana; Perez-Gomez, Gianna; Barrera-Allen, Lloyd; Szapocznik, José

    2013-01-01

    Background Walk Score® is a nationally and publicly available metric of neighborhood walkability based on proximity to amenities (e.g., retail, food, schools). However, few studies have examined the relationship of Walk Score to walking behavior. Purpose To examine the relationship of Walk Score to walking behavior in a sample of recent Cuban immigrants, who overwhelmingly report little choice in their selection of neighborhood built environments when they arrive in the U.S. Methods Participants were 391 recent healthy Cuban immigrants (M age=37.1 years) recruited within 90 days of arrival in the U.S., and assessed within 4 months of arrival (M=41.0 days in the U.S.), who resided throughout Miami-Dade County FL. Data on participants’ addresses, walking and sociodemographics were collected prospectively from 2008 to 2010. Analyses conducted in 2011 examined the relationship of Walk Score for each participant’s residential address in the U.S. to purposive walking, controlling for age, gender, education, BMI, days in the U.S., and habitual physical activity level in Cuba. Results For each 10-point increase in Walk Score, adjusting for covariates, there was a significant 19% increase in the likelihood of purposive walking, a 26% increase in the likelihood of meeting physical activity recommendations by walking, and 27% more minutes walked in the previous week. Conclusions Results suggest that Walk Score is associated with walking in a sample of recent immigrants who initially had little choice in where they lived in the U.S. These results support existing guidelines indicating that mixed land use (such as parks and restaurants near homes) should be included when designing walkable communities. PMID:23867028

  19. A natural walking monitor for pulmonary patients using mobile phones.

    PubMed

    Juen, Joshua; Cheng, Qian; Schatz, Bruce

    2015-07-01

    Mobile devices have the potential to continuously monitor health by collecting movement data including walking speed during natural walking. Natural walking is walking without artificial speed constraints present in both treadmill and nurse-assisted walking. Fitness trackers have become popular which record steps taken and distance, typically using a fixed stride length. While useful for everyday purposes, medical monitoring requires precise accuracy and testing on real patients with a scientifically valid measure. Walking speed is closely linked to morbidity in patients and widely used for medical assessment via measured walking. The 6-min walk test (6MWT) is a standard assessment for chronic obstructive pulmonary disease and congestive heart failure. Current generation smartphone hardware contains similar sensor chips as in medical devices and popular fitness devices. We developed a middleware software, MoveSense, which runs on standalone smartphones while providing comparable readings to medical accelerometers. We evaluate six machine learning methods to obtain gait speed during natural walking training models to predict natural walking speed and distance during a 6MWT with 28 pulmonary patients and ten subjects without pulmonary condition. We also compare our model's accuracy to popular fitness devices. Our universally trained support vector machine models produce 6MWT distance with 3.23% error during a controlled 6MWT and 11.2% during natural free walking. Furthermore, our model attains 7.9% error when tested on five subjects for distance estimation compared to the 50-400% error seen in fitness devices during natural walking.

  20. Association between Six Minute Walk Test and All-Cause Mortality, Coronary Heart Disease-Specific Mortality, and Incident Coronary Heart Disease

    PubMed Central

    Yazdanyar, Ali; Aziz, Michael M; Enright, Paul L; Edmundowicz, Daniel; Boudreau, Robert; Sutton-Tyrell, Kim; Kuller, Lewis; Newman, Anne B

    2015-01-01

    Objectives To examine the association between six-minute walk test (6 MWT) performance and all-cause mortality, coronary heart disease mortality, and incident coronary heart disease in older adults. Methods We conducted a time-to-event analysis of 1,665 Cardiovascular Health Study participants with a 6 MWT and without prevalent cardiovascular disease. Results During a mean follow-up of 8 years, there were 305 incident coronary heart disease events, 504 deaths of which 100 were coronary heart disease-related deaths. The 6 MWT performance in the shortest two distance quintiles was associated with increased risk of all-cause mortality (290-338 meters: HR 1.7; 95% CI, 1.2-2.5; <290 meters: HR 2.1; 95% CI, 1.4-3.0). The adjusted risk of coronary heart disease mortality incident events among those with a 6 MWT <290 meters was not significant. Discussion Performance on the 6 MWT is independently associated with all-cause mortality and is of prognostic utility in community-dwelling older adults. PMID:24695552

  1. Association between Modified Shuttle Walk Test and cardiorespiratory fitness in overweight/obese adults with primary hypertension: EXERDIET-HTA study.

    PubMed

    Jurio-Iriarte, Borja; Gorostegi-Anduaga, Ilargi; Aispuru, G Rodrigo; Pérez-Asenjo, Javier; Brubaker, Peter H; Maldonado-Martín, Sara

    2017-02-07

    The aims of the study were to evaluate the relationship between Modified Shuttle Walk Test (MSWT) with peak oxygen uptake (V˙O2peak) in overweight/obese people with primary hypertension (HTN) and to develop an equation for the MSWT to predict V˙O2peak. Participants (N = 256, 53.9 ± 8.1 years old) with HTN and overweight/obesity performed a cardiorespiratory exercise test to peak exertion on an upright bicycle ergometer using an incremental ramp protocol and the 15-level MSWT. The formula of Singh et al was used as a template to predict V˙O2peak, and a new equation was generated from the measured V˙O2peak-MSWT relationship in this investigation. The correlation between measured and predicted V˙O2peak for Singh et al equation was moderate (r = 0.60, P < .001) with a standard error of the estimate (SEE) of 4.92 mL·kg(-1) minute(-1), SEE% = 21%. The correlation between MSWT and measured V˙O2peak as well as for the new equation was strong (r = 0.72, P < .001) with a SEE of 4.35 mL·kg(-1) minute(-1), SEE% = 19%. These results indicate that MSWT does not accurately predict functional capacity in overweight/obese people with HTN and questions the validity of using this test to evaluate exercise intolerance. A more accurate determination from a new equation in the current study incorporating more variables from MSWT to estimate V˙O2peak has been performed but still results in substantial error.

  2. Testing for the presence and source of nonstationarity in United States energy efficiency: Time trends, hysteresis or random walk?

    NASA Astrophysics Data System (ADS)

    McArdle, Paul Francis

    This research tests for the presence and source of non-stationarity in U.S. aggregate energy efficiency for the 1900-1991 period. An outlier/intervention model is used to test for the presence of a unit-root in aggregate energy efficiency against the alternative hypothesis of a segmented/broken trend. A decomposed energy price model is also used to test if hysteresis in energy efficiency results from an asymmetrical response to energy price changes. The analysis revealed four distinct stages in aggregate energy efficiency during the 20th century: (1) the 1900-1920 period characterized by highly volatile decreases in energy efficiency caused by rapid industrialization and transition to a fossil-fueled economy; (2) the 1920-1949 period distinguished by a persistent increase in energy efficiency as the economy became adept at harnessing fossil energy; (3) the 1949-1972 period when energy efficiency remained stable within a narrow range; and (4) the 1973-1991 period when energy efficiency improved dramatically in response to the two oil prices shocks of the 1970s. Key modeling results include the following: (1) energy efficiency follows a unit-root process even when the effects of intervention outliers are taken into consideration, indicating that the unit-root hypothesis cannot be rejected against an alternative of a segmented/broken trend; (2) a major source of non-stationarity in energy efficiency is hysteresis induced by non-reverting changes in energy efficiency, in turn caused by dramatic increases in energy prices; and (3) although a strong negative trend appears to have occurred in aggregate energy intensity since 1920, it seems to be the result of energy price increases, rather than a general downward trend. An important economic implication of the analysis is that energy price increases appear to impact energy efficiency, while energy price decreases appear to have much less effect. This finding is consistent with much of the economic literature in this area

  3. Locomotor sequence learning in visually guided walking.

    PubMed

    Choi, Julia T; Jensen, Peter; Nielsen, Jens Bo

    2016-04-01

    Voluntary limb modifications must be integrated with basic walking patterns during visually guided walking. In this study we tested whether voluntary gait modifications can become more automatic with practice. We challenged walking control by presenting visual stepping targets that instructed subjects to modify step length from one trial to the next. Our sequence learning paradigm is derived from the serial reaction-time (SRT) task that has been used in upper limb studies. Both random and ordered sequences of step lengths were used to measure sequence-specific and sequence-nonspecific learning during walking. In addition, we determined how age (i.e., healthy young adults vs. children) and biomechanical factors (i.e., walking speed) affected the rate and magnitude of locomotor sequence learning. The results showed that healthy young adults (age 24 ± 5 yr,n= 20) could learn a specific sequence of step lengths over 300 training steps. Younger children (age 6-10 yr,n= 8) had lower baseline performance, but their magnitude and rate of sequence learning were the same compared with those of older children (11-16 yr,n= 10) and healthy adults. In addition, learning capacity may be more limited at faster walking speeds. To our knowledge, this is the first study to demonstrate that spatial sequence learning can be integrated with a highly automatic task such as walking. These findings suggest that adults and children use implicit knowledge about the sequence to plan and execute leg movement during visually guided walking.

  4. Walking on music.

    PubMed

    Styns, Frederik; van Noorden, Leon; Moelants, Dirk; Leman, Marc

    2007-10-01

    The present study focuses on the intricate relationship between human body movement and music, in particular on how music may influence the way humans walk. In an experiment, participants were asked to synchronize their walking tempo with the tempo of musical and metronome stimuli. The walking tempo and walking speed were measured. The tempi of the stimuli varied between 50 and 190 beats per minute. The data revealed that people walk faster on music than on metronome stimuli and that walking on music can be modeled as a resonance phenomenon that is related to the perceptual resonance phenomenon as described by Van Noorden and Moelants (Van Noorden, L., & Moelants, D. (1999). Resonance in the perception of musical pulse. Journal of New Music Research, 28, 43-66).

  5. Reduced Gravity Walking Simulator

    NASA Technical Reports Server (NTRS)

    1963-01-01

    A test subject being suited up for studies on the Reduced Gravity Walking Simulator located in the hanger at Langley Research Center. The initial version of this simulator was located inside the hanger. Later a larger version would be located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. Francis B. Smith wrote in his paper 'Simulators For Manned Space Research,' 'I would like to conclude this talk with a discussion of a device for simulating lunar gravity which is very effective and yet which is so simple that its cost is in the order of a few thousand dollars at most, rather than hundreds of thousands. With a little ingenuity, one could almost build this type simulator in his backyard for children to play on. The principle is ...if a test subject is suspended in a sling so that his body axis makes an angle of 9 1/2 degrees with the horizontal and if he then 'stands' on a platform perpendicular to his body axis, the component of the earth's gravity forcing him toward the platform is one times the sine of 9 1/2 degrees or approximately 1/6 of the earth's normal gravity field. That is, a 180 pound astronaut 'standing' on the platform would exert a force of only 30 pounds - the same as if he were standing upright on the lunar surface.' Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308; Francis B. Smith, 'Simulators For Manned Space Research,' Paper for 1966 IEEE International Convention, New York, NY, March 21-25, 1966.

  6. Treadmill walking is not equivalent to overground walking for the study of walking smoothness and rhythmicity in older adults.

    PubMed

    Row Lazzarini, Brandi S; Kataras, Theodore J

    2016-05-01

    Treadmills are appealing for gait studies, but some gait mechanics are disrupted during treadmill walking. The purpose of this study was to examine the effects of speed and treadmill walking on walking smoothness and rhythmicity of 40 men and women between the ages of 70-96 years. Gait smoothness was examined during overground (OG) and treadmill (TM) walking by calculating the harmonic ratio from linear accelerations measured at the level of the lumbar spine. Rhythmicity was quantified as the stride time standard deviation. TM walking was performed at two speeds: a speed matching the natural OG walk speed (TM-OG), and a preferred TM speed (PTM). A dual-task OG condition (OG-DT) was evaluated to determine if TM walking posed a similar cognitive challenge. Statistical analysis included a one-way Analysis of Variance with Bonferroni corrected post hoc comparisons and the Wilcoxon signed rank test for non-normally distributed variables. Average PTM speed was slower than OG. Compared to OG, those who could reach the TM-OG speed (74.3% of sample) exhibited improved ML smoothness and rhythmicity, and the slower PTM caused worsened vertical and AP smoothness, but did not affect rhythmicity. PTM disrupted smoothness and rhythmicity differently than the OG-DT condition, likely due to reduced speed. The use of treadmills for gait smoothness and rhythmicity studies in older adults is problematic; some participants will not achieve OG speed during TM walking, walking at the TM-OG speed artificially improves rhythmicity and ML smoothness, and walking at the slower PTM speed worsens vertical and AP gait smoothness.

  7. Virtually Abelian quantum walks

    NASA Astrophysics Data System (ADS)

    Mauro D'Ariano, Giacomo; Erba, Marco; Perinotti, Paolo; Tosini, Alessandro

    2017-01-01

    We study discrete-time quantum walks on Cayley graphs of non-Abelian groups, focusing on the easiest case of virtually Abelian groups. We present a technique to reduce the quantum walk to an equivalent one on an Abelian group with coin system having larger dimension. This method allows one to extend the notion of wave-vector to the virtually Abelian case and study analytically the walk dynamics. We apply the technique in the case of two quantum walks on virtually Abelian groups with planar Cayley graphs, finding the exact solution in terms of dispersion relation.

  8. The Utility of Exercise Testing in Patients with Lung Cancer.

    PubMed

    Ha, Duc; Mazzone, Peter J; Ries, Andrew L; Malhotra, Atul; Fuster, Mark

    2016-09-01

    The harm associated with lung cancer treatment include perioperative morbidity and mortality and therapy-induced toxicities in various organs, including the heart and lungs. Optimal treatment therefore entails a need for risk assessment to weigh the probabilities of benefits versus harm. Exercise testing offers an opportunity to evaluate a patient's physical fitness/exercise capacity objectively. In lung cancer, it is most often used to risk-stratify patients undergoing evaluation for lung cancer resection. In recent years, its use outside this context has been described, including in nonsurgical candidates and lung cancer survivors. In this article we review the physiology of exercise testing and lung cancer. Then, we assess the utility of exercise testing in patients with lung cancer in four contexts (preoperative evaluation for lung cancer resection, after lung cancer resection, lung cancer prognosis, and assessment of efficiency of exercise training programs) after systematically identifying original studies involving the most common forms of exercise tests in this patient population: laboratory cardiopulmonary exercise testing and simple field testing with the 6-minute walk test, shuttle walk test, and/or stair-climbing test. Lastly, we propose a conceptual framework for risk assessment of patients with lung cancer who are being considered for therapy and identify areas for further studies in this patient population.

  9. Walking dynamics are symmetric (enough)

    PubMed Central

    Ankaralı, M. Mert; Sefati, Shahin; Madhav, Manu S.; Long, Andrew; Bastian, Amy J.; Cowan, Noah J.

    2015-01-01

    Many biological phenomena such as locomotion, circadian cycles and breathing are rhythmic in nature and can be modelled as rhythmic dynamical systems. Dynamical systems modelling often involves neglecting certain characteristics of a physical system as a modelling convenience. For example, human locomotion is frequently treated as symmetric about the sagittal plane. In this work, we test this assumption by examining human walking dynamics around the steady state (limit-cycle). Here, we adapt statistical cross-validation in order to examine whether there are statistically significant asymmetries and, even if so, test the consequences of assuming bilateral symmetry anyway. Indeed, we identify significant asymmetries in the dynamics of human walking, but nevertheless show that ignoring these asymmetries results in a more consistent and predictive model. In general, neglecting evident characteristics of a system can be more than a modelling convenience—it can produce a better model. PMID:26236826

  10. Effects of short-term Nordic walking training on sarcopenia-related parameters in women with low bone mass: a preliminary study

    PubMed Central

    Ossowski, Zbigniew Marcin; Skrobot, Wojciech; Aschenbrenner, Piotr; Cesnaitiene, Vida Janina; Smaruj, Mirosław

    2016-01-01

    Background Several studies have demonstrated the positive effects of physical activity on skeletal muscle mass and muscle strength in women with osteoporosis. However, the impact of Nordic walking training on sarcopenia-related parameters in women with low bone mass remains unknown. Therefore, the purpose of this study was to evaluate the impact of 12 weeks of Nordic walking training on skeletal muscle index, muscle strength, functional mobility, and functional performance in women with low bone mass. Materials and methods The participants were 45 women, aged 63–79 years, with osteopenia or osteoporosis. The subjects were randomly assigned either to an experimental group (12 weeks of Nordic walking training, three times a week) or to a control group. Skeletal muscle mass and other body composition factors were measured with octapolar bioimpedance InBody 720 analyser. Knee extensor and flexor isometric muscle strength were measured using Biodex System 4 Pro™ dynamometers. This study also used a SAEHAN Digital Hand Dynamometer to measure handgrip muscle strength. The timed up-and-go test was used to measure functional mobility, and the 6-minute walk test was used to measure functional performance. Results Short-term Nordic walking training induced a significant increase in skeletal muscle mass (P=0.007), skeletal muscle index (P=0.007), strength index of the knee extensor (P=0.016), flexor (P<0.001), functional mobility (P<0.001), and functional performance (P<0.001) and a significant decrease in body mass (P=0<006), body mass index (P<0.001), and percent body fat (P<0.001) in participants. Regarding handgrip muscle strength, no improvement was registered (P=0.315). No significant changes in any of the analyzed parameters were observed in the control group. Conclusion Overall, short-term Nordic walking training induces positive changes in knee muscle strength and functional performance in women with low bone mass. This finding could be applied in clinical

  11. Walking cavity solitons

    SciTech Connect

    Skryabin, Dmitry V.; Champneys, Alan R.

    2001-06-01

    A family of walking solitons is obtained for the degenerate optical parametric oscillator below threshold. The loss-driven mechanism of velocity selection for these structures is described analytically and numerically. Our approach is based on understanding the role played by the field momentum and generic symmetry properties and, therefore, it can be easily generalized to other dissipative multicomponent models with walk off.

  12. Walking boot assembly

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C.; Chambers, A. B.; Stjohn, R. H. (Inventor)

    1977-01-01

    A walking boot assembly particularly suited for use with a positively pressurized spacesuit is presented. A bootie adapted to be secured to the foot of a wearer, an hermetically sealed boot for receiving the bootie having a walking sole, an inner sole, and an upper portion adapted to be attached to an ankle joint of a spacesuit, are also described.

  13. Lévy walks

    NASA Astrophysics Data System (ADS)

    Zaburdaev, V.; Denisov, S.; Klafter, J.

    2015-04-01

    Random walk is a fundamental concept with applications ranging from quantum physics to econometrics. Remarkably, one specific model of random walks appears to be ubiquitous across many fields as a tool to analyze transport phenomena in which the dispersal process is faster than dictated by Brownian diffusion. The Lévy-walk model combines two key features, the ability to generate anomalously fast diffusion and a finite velocity of a random walker. Recent results in optics, Hamiltonian chaos, cold atom dynamics, biophysics, and behavioral science demonstrate that this particular type of random walk provides significant insight into complex transport phenomena. This review gives a self-consistent introduction to Lévy walks, surveys their existing applications, including latest advances, and outlines further perspectives.

  14. A simple semipaced 3-minute chair rise test for routine exercise tolerance testing in COPD

    PubMed Central

    Aguilaniu, Bernard; Roth, Hubert; Gonzalez-Bermejo, Jesus; Jondot, Marie; Maitre, Jocelyne; Denis, François; Similowski, Thomas

    2014-01-01

    The functional work capacity of chronic obstructive pulmonary disease (COPD) patients is usually assessed with walk tests such as the 6-minute walk test (6MWT) or the shuttle test. Because these exercise modalities require a controlled environment which limits their use by pulmonologists and severely restricts their use among general practitioners, different modalities of a short (1 minute or less) sit-to-stand test were recently proposed. In this study, we evaluated a new modality of a semipaced 3-minute chair rise test (3CRT) in 40 patients with COPD, and compared the reproducibility of physiological responses and symptoms during the 3CRT and their interchangeability with the 6MWT. The results demonstrate that physiological variables, heart rate, pulse oxygen saturation, work done, and symptoms (Borg dyspnea and fatigue scores), during the 3CRT were highly reproducible, and that the physiological responses and symptoms obtained during the 3CRT and the 6MWT were interchangeable for most patients. Moreover, these preliminary data suggest that patients able to perform more than 50 rises during 3 minutes had no significant disability. The simplicity and ease of execution of the 3CRT will facilitate the assessment of exercise symptoms and disability in COPD patients during routine consultations with pulmonologists and general practitioners, and will thus contribute to the improved management of COPD patients. PMID:25285001

  15. The work of walking: a calorimetric study.

    PubMed

    Webb, P; Saris, W H; Schoffelen, P F; Van Ingen Schenau, G J; Ten Hoor, F

    1988-08-01

    Experiments were designed to test the traditional assumption that during level walking all of the energy from oxidation of fuel appears as heat and no work is done. Work is force expressed through distance, or energy transferred from a man to the environment, but not as heat. While wearing a suit calorimeter in a respiration chamber, five women and five men walked for 70 to 90 min on a level treadmill at 2.5, 4.6, and 6.7 km.h-1 and pedalled a cycle ergometer for 70 to 90 min against 53 and 92 W loads. They also walked with a weighted backpack and against a horizontal load. During cycling, energy from fuel matched heat loss plus the power measured by the ergometer. During walking, however, energy from fuel exceeded that which appeared as heat, meaning that work was done. The power increased with walking speed; values were 14, 29, and 63 W, which represented 11, 12, and 13% of the incremental cost of fuel above the resting level. Vertical and horizontal loads increased the fuel cost and heat loss of walking but did not alter the power output. This work energy did not re-appear as thermal energy during 18 h of recovery. The most likely explanation of the work done is in the inter-action between the foot and the ground, such as compressing the heel of the shoe and bending the sole. We conclude that work is done in level walking.

  16. Walking dreams in congenital and acquired paraplegia.

    PubMed

    Saurat, Marie-Thérèse; Agbakou, Maité; Attigui, Patricia; Golmard, Jean-Louis; Arnulf, Isabelle

    2011-12-01

    To test if dreams contain remote or never-experienced motor skills, we collected during 6 weeks dream reports from 15 paraplegics and 15 healthy subjects. In 9/10 subjects with spinal cord injury and in 5/5 with congenital paraplegia, voluntary leg movements were reported during dream, including feelings of walking (46%), running (8.6%), dancing (8%), standing up (6.3%), bicycling (6.3%), and practicing sports (skiing, playing basketball, swimming). Paraplegia patients experienced walking dreams (38.2%) just as often as controls (28.7%). There was no correlation between the frequency of walking dreams and the duration of paraplegia. In contrast, patients were rarely paraplegic in dreams. Subjects who had never walked or stopped walking 4-64 years prior to this study still experience walking in their dreams, suggesting that a cerebral walking program, either genetic or more probably developed via mirror neurons (activated when observing others performing an action) is reactivated during sleep.

  17. Uphill and Downhill Walking in Multiple Sclerosis

    PubMed Central

    Samaei, Afshin; Hajihasani, Abdolhamid; Fatemi, Elham; Motaharinezhad, Fatemeh

    2016-01-01

    Background: Various exercise protocols have been recommended for patients with multiple sclerosis (MS). We investigated the effects of uphill and downhill walking exercise on mobility, functional activities, and muscle strength in MS patients. Methods: Thirty-four MS patients were randomly allocated to either the downhill or uphill treadmill walking group for 12 sessions (3 times/wk) of 30 minutes' walking on a 10% negative slope (n = 17) or a 10% positive slope (n = 17), respectively. Measurements were taken before and after the intervention and after 4-week follow-up and included fatigue by Modified Fatigue Impact Scale; mobility by Modified Rivermead Mobility Index; disability by Guy's Neurological Disability Scale; functional activities by 2-Minute Walk Test, Timed 25-Foot Walk test, and Timed Up and Go test; balance indices by Biodex Balance System; and quadriceps and hamstring isometric muscles by torque of left and right knee joints. Analysis of variance with repeated measures was used to investigate the intervention effects on the measurements. Results: After the intervention, significant improvement was found in the downhill group versus the uphill group in terms of fatigue, mobility, and disability indices; functional activities; balance indices; and quadriceps isometric torque (P < .05). The results were stable at 4-week follow-up. Conclusions: Downhill walking on a treadmill may improve muscle performance, functional activity, and balance control in MS patients. These findings support the idea of using eccentric exercise training in MS rehabilitation protocols. PMID:26917996

  18. Can treadmill walking be used to assess propulsion generation?

    PubMed

    Goldberg, Evan J; Kautz, Steven A; Neptune, Richard R

    2008-01-01

    Instrumented treadmills offer significant advantages for analysis of human locomotion, including recording consecutive steady-state gait cycles, precisely controlling walking speed, and avoiding force plate targeting. However, some studies of hemiparetic walking on a treadmill have suggested that the moving treadmill belt may fundamentally alter propulsion mechanics. Any differences in propulsion mechanics during treadmill walking would be problematic since recent studies assessing propulsion have provided fundamental insight into hemiparetic walking. The purpose of this study was to test the hypothesis that there would be no difference in the generation of anterior/posterior (A/P) propulsion by performing a carefully controlled comparison of the A/P ground reaction forces (GRFs) and impulses in healthy adults during treadmill and overground walking. Gait data were collected from eight subjects walking overground and on a treadmill with speed and cadence controlled. Peak negative and positive horizontal GRFs in early and late stance, respectively, were reduced by less than 5% of body weight (p<0.05) during treadmill walking compared to overground walking. The magnitude of the braking impulse was similarly lower (p<0.05) during treadmill walking, but no significant difference was found between propulsion impulses. While there were some subtle differences in A/P GRFs between overground and treadmill walking, these results suggest there is no fundamental difference in propulsion mechanics. We conclude that treadmill walking can be used to investigate propulsion generation in healthy and by implication clinical populations.

  19. Device-measured physical activity versus six-minute walk test as a predictor of reverse remodeling and outcome after cardiac resynchronization therapy for heart failure.

    PubMed

    Vegh, Eszter Maria; Kandala, Jagdesh; Orencole, Mary; Upadhyay, Gaurav A; Sharma, Ajay; Miller, Alexandra; Merkely, Bela; Parks, Kimberly A; Singh, Jagmeet P

    2014-05-01

    Implanted devices can provide objective assessment of physical activity over prolonged periods. The purpose of this study was to investigate the prognostic value of device-measured physical activity data compared with a six-minute walk test (6MWT) in predicting clinical response to cardiac resynchronization therapy (CRT). This was a single-center study in which patients who underwent CRT for standard indications were evaluated. Daily physical activity and 6MWT were evaluated postimplant at 1, 3, and 6 months. The primary end point was a composite of heart failure hospitalization, transplant, left ventricular (LV) assist device, and all-cause death at 3 years. Echocardiographic response, defined as a ≥10% improvement in LV ejection fraction (LVEF), at 6 months was the secondary end point. About 164 patients were included: average age was 67.3 ± 12.9 years, 77% were men, baseline LVEF was 25% ± 7%. Kaplan-Meier curves showed superior freedom from the composite end point in the highest tertile of both 6MWT and physical activity compared with the lowest tertile (41 vs 23 cases, respectively, p <0.001) for 6MWT and for activity (22 vs 7 cases, respectively, p = 0.001). In an adjusted multivariate model, independent predictors of improved clinical outcome included 1-month physical activity (hazard ratio 0.546, 95% confidence interval [CI] 0.361 to 0.824, p = 0.004) and 6MWT (hazard ratio 0.581, 95% CI 0.425 to 0.795, p = 0.001). An additional hour of higher activity at 1 month translated to a 1.38 times (95% CI 1.075 to 1.753, p = 0.011) higher likelihood of improved echocardiographic response. In conclusion, device-based measures of physical activity may be useful in predicting echocardiographic reverse remodeling and long-term clinical outcome in patients receiving CRT.

  20. Random walks in the history of life

    PubMed Central

    Cornette, James L.; Lieberman, Bruce S.

    2004-01-01

    The simplest null hypothesis for evolutionary time series is that the observed data follow a random walk. We examined whether aspects of Sepkoski's compilation of marine generic diversity depart from a random walk by using statistical tests from econometrics. Throughout most of the Phanerozoic, the random-walk null hypothesis is not rejected for marine diversity, accumulated origination or accumulated extinction, suggesting that either these variables were correlated with environmental variables that follow a random walk or so many mechanisms were affecting these variables, in different ways, that the resultant trends appear random. The only deviation from this pattern involves rejection of the null hypothesis for roughly the last 75 million years for the diversity and accumulated origination time series. PMID:14684835

  1. Crossover from random walk to self-avoiding walk

    NASA Astrophysics Data System (ADS)

    Rieger, Jens

    1988-11-01

    A one-dimensional n-step random walk on openZ1 which must not visit a vertex more than k times is studied via Monte Carlo methods. The dependences of the mean-square end-to-end distance of the walk and of the fraction of trapped walks on λ=(k-1)/n will be given for the range from λ=0 (self-avoiding walk) to λ=1 (unrestricted random walk). From the results it is conjectured that in the limit n-->∞ the walk obeys simple random walk statistics with respect to its static properties for all λ>0.

  2. When Human Walking is a Random Walk

    NASA Astrophysics Data System (ADS)

    Hausdorff, J. M.

    1998-03-01

    The complex, hierarchical locomotor system normally does a remarkable job of controlling an inherently unstable, multi-joint system. Nevertheless, the stride interval --- the duration of a gait cycle --- fluctuates from one stride to the next, even under stationary conditions. We used random walk analysis to study the dynamical properties of these fluctuations under normal conditions and how they change with disease and aging. Random walk analysis of the stride-to-stride fluctuations of healthy, young adult men surprisingly reveals a self-similar pattern: fluctuations at one time scale are statistically similar to those at multiple other time scales (Hausdorff et al, J Appl Phsyiol, 1995). To study the stability of this fractal property, we analyzed data obtained from healthy subjects who walked for 1 hour at their usual pace, as well as at slower and faster speeds. The stride interval fluctuations exhibited long-range correlations with power-law decay for up to a thousand strides at all three walking rates. In contrast, during metronomically-paced walking, these long-range correlations disappeared; variations in the stride interval were uncorrelated and non-fractal (Hausdorff et al, J Appl Phsyiol, 1996). To gain insight into the mechanism(s) responsible for this fractal property, we examined the effects of aging and neurological impairment. Using detrended fluctuation analysis (DFA), we computed α, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. α was significantly lower in healthy elderly subjects compared to young adults (p < .003) and in subjects with Huntington's disease, a neuro-degenerative disorder of the central nervous system, compared to disease-free controls (p < 0.005) (Hausdorff et al, J Appl Phsyiol, 1997). α was also significantly related to degree of functional impairment in subjects with Huntington's disease (r=0.78). Recently, we have observed that just as

  3. Effects of Walking Direction and Cognitive Challenges on Gait in Persons with Multiple Sclerosis

    PubMed Central

    Wajda, Douglas A.; Sandroff, Brian M.; Pula, John H.; Motl, Robert W.; Sosnoff, Jacob J.

    2013-01-01

    Declines in walking performance are commonly seen when undergoing a concurrent cognitive task in persons with multiple sclerosis (MS). The purpose of this study was to determine the effect of walking direction and simultaneous cognitive task on the spatiotemporal gait parameters in persons with MS compared to healthy controls. Ten persons with MS (Median EDSS, 3.0) and ten healthy controls took part in this pilot study. Participants performed 4 walking trials at their self-selected comfortable pace. These trials included forward walking, forward walking with a cognitive task, backward walking, and backward walking with a cognitive task. Walking performance was indexed with measures of velocity, cadence, and stride length for each testing condition. The MS group walked slower with significantly reduced stride length compared to the control group. The novel observation of this investigation was that walking differences between persons with MS and healthy controls were greater during backward walking, and this effect was further highlighted during backward walking with added cognitive test. This raises the possibility that backward walking tests could be an effective way to examine walking difficulties in individuals with MS with relatively minimal walking impairment. PMID:24223308

  4. Effects of walking direction and cognitive challenges on gait in persons with multiple sclerosis.

    PubMed

    Wajda, Douglas A; Sandroff, Brian M; Pula, John H; Motl, Robert W; Sosnoff, Jacob J

    2013-01-01

    Declines in walking performance are commonly seen when undergoing a concurrent cognitive task in persons with multiple sclerosis (MS). The purpose of this study was to determine the effect of walking direction and simultaneous cognitive task on the spatiotemporal gait parameters in persons with MS compared to healthy controls. Ten persons with MS (Median EDSS, 3.0) and ten healthy controls took part in this pilot study. Participants performed 4 walking trials at their self-selected comfortable pace. These trials included forward walking, forward walking with a cognitive task, backward walking, and backward walking with a cognitive task. Walking performance was indexed with measures of velocity, cadence, and stride length for each testing condition. The MS group walked slower with significantly reduced stride length compared to the control group. The novel observation of this investigation was that walking differences between persons with MS and healthy controls were greater during backward walking, and this effect was further highlighted during backward walking with added cognitive test. This raises the possibility that backward walking tests could be an effective way to examine walking difficulties in individuals with MS with relatively minimal walking impairment.

  5. Predictors of Improved Walking after a Supervised Walking Exercise Program in Men and Women with Peripheral Artery Disease

    PubMed Central

    Montgomery, Polly S.

    2016-01-01

    We compared the changes in ambulatory outcomes between men and women with symptomatic peripheral arterial disease (PAD) following completion of a supervised, on-site, treadmill exercise program, and we determined whether exercise training variables and baseline clinical characteristics were predictive of changes in ambulatory outcomes in men and women. Twenty-three men and 25 women completed the supervised exercise program, consisting of intermittent walking to mild-to-moderate claudication pain for three months. Men and women significantly increased claudication onset time (COT) (p < 0.001 and p < 0.01, resp.) and peak walking time (PWT) (p < 0.001 for each group). However, change in PWT was less in women (54%) than in men (77%) (p < 0.05). Neither group significantly changed 6-minute walk distance (6MWD). In women, baseline COT was the only predictor for the change in COT (p = 0.007) and the change in PWT (p = 0.094). In men, baseline COT (p < 0.01) and obesity (p < 0.10) were predictors for the change in COT, and obesity was the only predictor for the change in PWT (p = 0.002). Following a supervised, on-site, treadmill exercise program, women had less improvement in PWT than men, and neither men nor women improved submaximal, overground 6MWD. Furthermore, obese men and patients with lower baseline COT were least responsive to supervised exercise. This trial is registered with ClinicalTrial.gov, unique identifier: NCT00618670. PMID:28116164

  6. Six-minute stepper test: a valid clinical exercise tolerance test for COPD patients

    PubMed Central

    Grosbois, JM; Riquier, C; Chehere, B; Coquart, J; Béhal, H; Bart, F; Wallaert, B; Chenivesse, C

    2016-01-01

    Introduction Exercise tolerance testing is an integral part of the pulmonary rehabilitation (PR) management of patients with chronic obstructive pulmonary disease (COPD). The 6-minute stepper test (6MST) is a new, well-tolerated, reproducible exercise test, which can be performed without any spatial constraints. Objective The aim of this study was to compare the results of the 6MST to those obtained during a 6-minute walk test (6MWT) and cardiopulmonary exercise testing (CPET) in a cohort of COPD patients. Methods Ninety-one COPD patients managed by outpatient PR and assessed by 6MST, 6MWT, and CPET were retrospectively included in this study. Correlations between the number of steps on the 6MST, the distance covered on the 6MWT, oxygen consumption, and power at the ventilatory threshold and at maximum effort during CPET were analyzed before starting PR, and the improvement on the 6MST and 6MWT was compared after PR. Results The number of steps on the 6MST was significantly correlated with the distance covered on the 6MWT (r=0.56; P<0.0001), the power at maximum effort (r=0.46; P<0.0001), and oxygen consumption at maximum effort (r=0.39; P<0.005). Performances on the 6MST and 6MWT were significantly improved after PR (570 vs 488 steps, P=0.001 and 448 vs 406 m, respectively; P<0.0001). Improvements of the 6MST and 6MWT after PR were significantly correlated (r=0.34; P=0.03). Conclusion The results of this study show that the 6MST is a valid test to evaluate exercise tolerance in COPD patients. The use of this test in clinical practice appears to be particularly relevant for the assessment of patients managed by home PR. PMID:27099483

  7. Walking On Air

    NASA Video Gallery

    This video features a series of time lapse sequences photographed by the Expedition 30 crew aboard the International Space Station. Set to the song "€œWalking in the Air,"€ by Howard Blake, the v...

  8. Gait or Walking Problems

    MedlinePlus

    ... a device is justified,” says Dr. Aisen. Gait Research & Technology At present, people with walking limitations related to ... independent through physical therapy, exercise, medication, and assistive ... is optimistic that research being done in other conditions, such as spinal ...

  9. Quantum walk and potential application

    NASA Astrophysics Data System (ADS)

    Wang, J. B.; Douglas, B. L.

    2010-06-01

    Quantum walk represents a generalised version of the well-known classical random walk. Regardless of their apparent connection, the dynamics of quantum walk is often non-intuitive and far deviate from its classical counterpart. However, despite such potentially superior efficiency in quantum walks, it has yet to be applied to problems of practical importance. In this paper, we will give a brief introduction to quantum walks and discuss potential applications.

  10. Assessing walking speed in clinical research: a systematic review

    PubMed Central

    Graham, James E.; Ostir, Glenn V.; Fisher, Steven R.; Ottenbacher, Kenneth J.

    2009-01-01

    Objective To provide a systematic review and describe how assessments of walking speed are reported in the health care literature. Methods MEDLINE electronic database and bibliographies of select articles were searched for terms describing walking speed and distances walked. The search was limited to English language journals from 1996 to 2006. The initial title search yielded 793 articles. A review of the abstracts reduced the number to 154 articles. Of these, 108 provided sufficient information for inclusion in the current review. Results Of the 108 studies included in the review 61 were descriptive, 39 intervention and 8 randomized controlled trials. Neurological (n = 55) and geriatric (n = 27) were the two most frequent participant groups in the studies reviewed. Instruction to walk at a usual or normal speed was reported in 55 of the studies, while 31 studies did not describe speed instructions. A static (standing) start was slightly more common than a dynamic (rolling) start (30 vs 26 studies); however, half of the studies did not describe the starting protocol. Walking 10, 6 and 4 m was the most common distances used, and reported in 37, 20 and 11 studies respectively. Only four studies included information on whether verbal encouragement was given during the walking task. Conclusions Tests of walking speed have been used in a wide range of populations. However, methodologies and descriptions of walking tests vary widely from study to study, which makes comparison difficult. There is a need to find consensus for a standardized walking test methodology. PMID:18462283

  11. D.U.C.K. Walking.

    ERIC Educational Resources Information Center

    Steller, Jenifer J.

    This manual presents a schoolwide walking program that includes aerobic fitness information, curriculum integration, and walking tours. "Discover and Understand Carolina Kids by Walking" is D.U.C.K. Walking. An aerobic walking activity, D.U.C.K. Walking has two major goals: (1) to promote regular walking as a way to exercise at any age;…

  12. Give your ideas some legs: the positive effect of walking on creative thinking.

    PubMed

    Oppezzo, Marily; Schwartz, Daniel L

    2014-07-01

    Four experiments demonstrate that walking boosts creative ideation in real time and shortly after. In Experiment 1, while seated and then when walking on a treadmill, adults completed Guilford's alternate uses (GAU) test of creative divergent thinking and the compound remote associates (CRA) test of convergent thinking. Walking increased 81% of participants' creativity on the GAU, but only increased 23% of participants' scores for the CRA. In Experiment 2, participants completed the GAU when seated and then walking, when walking and then seated, or when seated twice. Again, walking led to higher GAU scores. Moreover, when seated after walking, participants exhibited a residual creative boost. Experiment 3 generalized the prior effects to outdoor walking. Experiment 4 tested the effect of walking on creative analogy generation. Participants sat inside, walked on a treadmill inside, walked outside, or were rolled outside in a wheelchair. Walking outside produced the most novel and highest quality analogies. The effects of outdoor stimulation and walking were separable. Walking opens up the free flow of ideas, and it is a simple and robust solution to the goals of increasing creativity and increasing physical activity.

  13. Stride Counting in Human Walking and Walking Distance Estimation Using Insole Sensors

    PubMed Central

    Truong, Phuc Huu; Lee, Jinwook; Kwon, Ae-Ran; Jeong, Gu-Min

    2016-01-01

    This paper proposes a novel method of estimating walking distance based on a precise counting of walking strides using insole sensors. We use an inertial triaxial accelerometer and eight pressure sensors installed in the insole of a shoe to record walkers’ movement data. The data is then transmitted to a smartphone to filter out noise and determine stance and swing phases. Based on phase information, we count the number of strides traveled and estimate the movement distance. To evaluate the accuracy of the proposed method, we created two walking databases on seven healthy participants and tested the proposed method. The first database, which is called the short distance database, consists of collected data from all seven healthy subjects walking on a 16 m distance. The second one, named the long distance database, is constructed from walking data of three healthy subjects who have participated in the short database for an 89 m distance. The experimental results show that the proposed method performs walking distance estimation accurately with the mean error rates of 4.8% and 3.1% for the short and long distance databases, respectively. Moreover, the maximum difference of the swing phase determination with respect to time is 0.08 s and 0.06 s for starting and stopping points of swing phases, respectively. Therefore, the stride counting method provides a highly precise result when subjects walk. PMID:27271634

  14. Give Your Ideas Some Legs: The Positive Effect of Walking on Creative Thinking

    ERIC Educational Resources Information Center

    Oppezzo, Marily; Schwartz, Daniel L.

    2014-01-01

    Four experiments demonstrate that walking boosts creative ideation in real time and shortly after. In Experiment 1, while seated and then when walking on a treadmill, adults completed Guilford's alternate uses (GAU) test of creative divergent thinking and the compound remote associates (CRA) test of convergent thinking. Walking increased 81% of…

  15. The effects of clothes on independent walking in toddlers.

    PubMed

    Théveniau, Nicolas; Boisgontier, Matthieu P; Varieras, Sabine; Olivier, Isabelle

    2014-01-01

    The spatiotemporal features of walking in toddlers are known to be related to the level of maturation of the central nervous system. However, previous studies did not assess whether there could be an effect of clothes on the acquisition of walking. In this study, it was hypothesized that clothes modify the toddlers' walking. To test this hypothesis, 22 healthy toddlers divided into 3 groups of walking experience were assessed in four clothing conditions (Diaper+Trousers; Diaper+Pants of tracksuit; Diaper; Underwear). Results revealed significant effects of clothing on velocity and step length of toddlers from 6 to 18 months of walking experience. These results suggested that biomechanical constraints induced by the textile features alter the walking of toddlers. Therefore, in studies of toddler's gait, the clothing worn should be carefully mentioned and controlled.

  16. Staggered quantum walks with Hamiltonians

    NASA Astrophysics Data System (ADS)

    Portugal, R.; de Oliveira, M. C.; Moqadam, J. K.

    2017-01-01

    Quantum walks are recognizably useful for the development of new quantum algorithms, as well as for the investigation of several physical phenomena in quantum systems. Actual implementations of quantum walks face technological difficulties similar to the ones for quantum computers, though. Therefore, there is a strong motivation to develop new quantum-walk models which might be easier to implement. In this work we present an extension of the staggered quantum walk model that is fitted for physical implementations in terms of time-independent Hamiltonians. We demonstrate that this class of quantum walk includes the entire class of staggered quantum walk model, Szegedy's model, and an important subset of the coined model.

  17. Walks on SPR neighborhoods.

    PubMed

    Caceres, Alan Joseph J; Castillo, Juan; Lee, Jinnie; St John, Katherine

    2013-01-01

    A nearest-neighbor-interchange (NNI)-walk is a sequence of unrooted phylogenetic trees, T1, T2, . . . , T(k) where each consecutive pair of trees differs by a single NNI move. We give tight bounds on the length of the shortest NNI-walks that visit all trees in a subtree-prune-and-regraft (SPR) neighborhood of a given tree. For any unrooted, binary tree, T, on n leaves, the shortest walk takes Θ(n²) additional steps more than the number of trees in the SPR neighborhood. This answers Bryant’s Second Combinatorial Challenge from the Phylogenetics Challenges List, the Isaac Newton Institute, 2011, and the Penny Ante Problem List, 2009.

  18. Comparison of nonmicroprocessor knee mechanism versus C-Leg on Prosthesis Evaluation Questionnaire, stumbles, falls, walking tests, stair descent, and knee preference.

    PubMed

    Kahle, Jason T; Highsmith, M Jason; Hubbard, Sandra L

    2008-01-01

    This study compared subjects' performance with a nonmicroprocessor knee mechanism (NMKM) versus a C-Leg on nine clinically repeatable evaluative measures. We recorded data on subjects' performance while they used an accommodated NMKM and, following a 90-day accommodation period, the C-Leg in a convenience sample of 19 transfemoral (TF) amputees (mean age 51 +/- 19) from an outpatient prosthetic clinic. We found that use of the C-Leg improved function in all outcomes: (1) Prosthesis Evaluation Questionnaire scores increased 20% (p = 0.007), (2) stumbles decreased 59% (p = 0.006), (3) falls decreased 64% (p = 0.03), (4) 75 m self-selected walking speed on even terrain improved 15% (p = 0.03), (5) 75 m fastest possible walking speed (FPWS) on even terrain improved 12% (p = 0.005), (6) 38 m FPWS on uneven terrain improved 21% (p < 0.001), (7) 6 m FPWS on even terrain improved 17% (p = 0.001), (8) Montreal Rehabilitation Performance Profile Performance Composite Scores for stair descent increased for 12 subjects, and (9) the C-Leg was preferred over the NMKM by 14 subjects. Four limited community ambulators (Medicare Functional Classification Level [MFCL] K2) increased their ambulatory functional level to unlimited community ambulation (MFCL K3). Objective evaluative clinical measures are vital for justifying the medical necessity of knee mechanisms for TF amputees. Use of the C-Leg improves performance and quality of life and can increase MFCL and community ambulation level.

  19. 10 CFR 431.302 - Definitions concerning walk-in coolers and walk-in freezers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning walk-in coolers and walk-in... FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers § 431.302 Definitions concerning walk-in coolers and walk-in freezers. Walk-in cooler and walk-in freezer mean...

  20. Locomotion: Why We Walk the Way We Walk.

    PubMed

    Bertram, John E A

    2015-09-21

    The way we walk determines the energetic investment needed. Humans spontaneously alter their walking style to exploit energetic opportunities. New research demonstrates the sensitivity and timing of this optimization and opens the door to discovering the underlying mechanisms.

  1. Efficacy of Halotherapy for Improvement of Pulmonary function Tests and Quality of Life of Non-Cystic Fibrosis Bronchiectatic Patients

    PubMed Central

    Rabbani, Bita; Najafizadeh, Katayoon; Vishteh, Hamid Reza Khodami; Shafaghi, Shadi; Karimi, Shirin; Mahmoodian, Saeid

    2013-01-01

    Background Halotherapy is a treatment modality suggested for patients with chronic pulmonary diseases. In this technique, inhalation of crystal salt stones extracted from mines improves patients’ pulmonary function tests and symptoms by facilitating the secretion or expulsion of phlegm and mucus and reducing the risk of bacterial infections. Bronchiectasis is chronic disease of the airways characterized by irreversible dilation of airways. It has a progressive course and despite the available treatments, many of these patients eventually enter the advanced phase of disease. The aim of this study was to evaluate the effect of halotherapy on pulmonary function tests and quality of life of non-CF bronchiectatic patients. Materials and Methods This clinical trial evaluated the results of spirometry and 6-minute walk test as well as the quality of life (according to SF-36 questionnaire) of stable non-CF bronchiectatic patients presenting to the pulmonary clinic before and after the use of salt spray for 2 months. Results Of 40 study patients, 20 were excluded due to various reasons and 20 were evaluated. The mean age of patients was 35±11 years and the underlying cause of disease was chronic pulmonary infection in 65% of cases. Comparison of the results of pulmonary function tests and 6-minute walk test and quality of life indices in SF-36 questionnaire before and after the intervention showed no significant difference (P > 0.05). However, 65% of patients were satisfied with halotherapy and requested to receive the medication again. Conclusion Our study results indicated that 2-month halotherapy with Salitair inhaler containing salt crystals extracted from the Klodawa mine in Poland could not improve the pulmonary function tests or quality of life of non-CF bronchiectatic patients. No significant side effects were noted in understudy patients. Future studies with larger sample size and longer duration of treatment are recommended to better determine the efficacy of

  2. Unobtrusive assessment of walking speed in the home using inexpensive PIR sensors

    PubMed Central

    Hagler, Stuart; Austin, Daniel; Kaye, Jeffrey; Pavel, Misha

    2010-01-01

    Walking speed and activity are important measures of functional ability in the elderly. Our earlier studies have suggested that continuous monitoring may allow us to detect changes in walking speed that are also predictive of cognitive changes. We evaluated the use of passive infrared (PIR) sensors for measuring walking speed in the home on an ongoing basis. In comparisons with gait mat estimates (ground truth) and the results of a timed walk test (the clinical gold standard) in 18 subjects, we found that the clinical measure overestimated typical walking speed, and the PIR sensor estimations of walking speed were highly correlated to actual gait speed. Examination of in-home walking patterns from more than 100,000 walking speed samples for these subjects suggested that we can accurately assess walking speed in the home. We discuss the potential of this approach for continuous assessment. PMID:19965096

  3. Walking Shoes: Features and Fit

    MedlinePlus

    Healthy Lifestyle Fitness Walking shoes have some features other shoes don't. Here's what to look for and ... 04, 2017 Original article: http://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/walking/art-20043897 . Mayo Clinic ...

  4. Understanding walking activity in multiple sclerosis: step count, walking intensity and uninterrupted walking activity duration related to degree of disability.

    PubMed

    Neven, An; Vanderstraeten, Annelien; Janssens, Davy; Wets, Geert; Feys, Peter

    2016-09-01

    In multiple sclerosis (MS), physical activity (PA) is most commonly measured as number of steps, while also walking intensity and walking activity duration are keys for a healthy lifestyle. The aim of this study was to investigate (1) the number of steps persons with MS (PwMS) take; (2) the number of steps they take at low and moderate intensity; and (3) their walking activity duration for 2, 3, 6, 10, 12 and 14 uninterrupted minutes; all related to the degree of disability. 64 PwMS participated, distinguished in a mild (n = 31) and moderate MS subgroup (n = 34) based on their ambulatory dysfunction (Disease Steps). Standardized clinical tests were performed, and step data from the StepWatch Activity Monitor were collected for seven consecutive days. The results showed that (1) step count in PwMS was lower than PA recommendations, and is negatively influenced by a higher disability degree. (2) No walking was registered during 77 % of the day. PwMS are making steps for 22 % at low and only 1 % at moderate intensity. (3) Both MS subgroups rarely walk for more than six uninterrupted minutes, especially not at moderate intensity. PwMS need to be encouraged to make steps at moderate intensity, and to make steps for longer periods of time (minimal ten uninterrupted minutes).

  5. Instrumental and Non-Instrumental Evaluation of 4-Meter Walking Speed in Older Individuals

    PubMed Central

    Maggio, Marcello; Ceda, Gian Paolo; Ticinesi, Andrea; De Vita, Francesca; Gelmini, Giovanni; Costantino, Cosimo; Meschi, Tiziana; Kressig, Reto W.; Cesari, Matteo; Fabi, Massimo; Lauretani, Fulvio

    2016-01-01

    Background Manual measurement of 4-meter gait speed by a stopwatch is the gold standard test for functional assessment in older adults. However, the accuracy of this technique may be biased by several factors, including intra- and inter-operator variability. Instrumental techniques of measurement using accelerometers may have a higher accuracy. Studies addressing the concordance between these two techniques are missing. The aim of the present community-based observational study was to compare manual and instrumental measurements of 4-meter gait speed in older individuals and to assess their relationship with other indicators of physical performance. Methods One-hundred seventy-two (69 men, 103 women) non-disabled community-dwellers aged ≥65 years were enrolled. They underwent a comprehensive geriatric assessment including physical function by Short Physical Performance Battery (SPPB), hand grip strength, and 6-minute walking test (6MWT). Timed usual walking speed on a 4-meter course was assessed by using both a stopwatch (4-meter manual measurement, 4-MM) and a tri-axial accelerometer (4-meter automatic measurement, 4-MA). Correlations between these performance measures were evaluated separately in men and women by partial correlation coefficients. Results In both genders, 4-MA was associated with 4-MM (men r = 0.62, p<0.001; women r = 0.73, p<0.001), handgrip strength (men r = 0.40, p = 0.005; women r = 0.29, p = 0.001) and 6MWT (men r = 0.50, p = 0.0004; women r = 0.22, p = 0.048). 4-MM was associated with handgrip strength and 6MWT in both men and women. Considering gait speed <0.6 m/s as diagnostic of dismobility syndrome, the two methods of assessment disagreed, with a different categorization of subjects, in 19% of men and 23% of women. The use of accelerometer resulted in 29 (13 M, 16 F) additional diagnoses of dismobility, compared with the 4-MM. Conclusions In an older population, the concordance of gait speeds manually or instrumentally assessed is not

  6. Walking with a Slower Friend

    ERIC Educational Resources Information Center

    Bailey, Herb; Kalman, Dan

    2011-01-01

    Fay and Sam go for a walk. Sam walks along the left side of the street while Fay, who walks faster, starts with Sam but walks to a point on the right side of the street and then returns to meet Sam to complete one segment of their journey. We determine Fay's optimal path minimizing segment length, and thus maximizing the number of times they meet…

  7. Take a Planet Walk

    ERIC Educational Resources Information Center

    Schuster, Dwight

    2008-01-01

    Physical models in the classroom "cannot be expected to represent the full-scale phenomenon with complete accuracy, not even in the limited set of characteristics being studied" (AAAS 1990). Therefore, by modifying a popular classroom activity called a "planet walk," teachers can explore upper elementary students' current understandings; create an…

  8. Walking Advisement: Program Description.

    ERIC Educational Resources Information Center

    Byram Hills School District, Armonk, NY.

    The Walking Advisement program at Crittenden Middle School in Armonk, New York was started during the 1984-1985 school year. It was based on the work of Alfred Arth, a middle school specialist at the University of Wyoming. Essentially, the program attempts to expand the guidance function of the school by bringing faculty and students together to…

  9. A Walk Back.

    ERIC Educational Resources Information Center

    Greenslade, Cleo B.

    1988-01-01

    Discusses a walking trip through Elfers, Florida, which gives intermediate level students a basis for a real understanding of the state's history, climate, economy, and natural resources. Describes how students prepare for the outing by examining maps and interviewing their parents and grandparents about life when they were in school. (GEA)

  10. Walking Out Graphs

    ERIC Educational Resources Information Center

    Shen, Ji

    2009-01-01

    In the Walking Out Graphs Lesson described here, students experience several types of representations used to describe motion, including words, sentences, equations, graphs, data tables, and actions. The most important theme of this lesson is that students have to understand the consistency among these representations and form the habit of…

  11. Deterministic Walks with Choice

    SciTech Connect

    Beeler, Katy E.; Berenhaut, Kenneth S.; Cooper, Joshua N.; Hunter, Meagan N.; Barr, Peter S.

    2014-01-10

    This paper studies deterministic movement over toroidal grids, integrating local information, bounded memory and choice at individual nodes. The research is motivated by recent work on deterministic random walks, and applications in multi-agent systems. Several results regarding passing tokens through toroidal grids are discussed, as well as some open questions.

  12. Walking in My Shoes

    ERIC Educational Resources Information Center

    Salia, Hannah

    2010-01-01

    The Walking in My Shoes curriculum at St. Thomas School in Medina, Washington, has been developed to deepen students' understanding of their own heritage and the cultural similarities and differences among their global peers. Exploring the rich diversity of the world's cultural heritage and the interactions of global migrations throughout history,…

  13. A Walk through Time.

    ERIC Educational Resources Information Center

    Renfroe, Mark; Letendre, Wanda

    1996-01-01

    Describes a seventh-grade class project where students constructed a "time tunnel" (a walk-through display with models and exhibits illustrating various themes and eras). Beginning modestly, the tunnel grew over seven years to include 11 different display scenes. Discusses the construction of the project and benefits to the school. (MJP)

  14. Shared muscle synergies in human walking and cycling.

    PubMed

    Barroso, Filipe O; Torricelli, Diego; Moreno, Juan C; Taylor, Julian; Gomez-Soriano, Julio; Bravo-Esteban, Elisabeth; Piazza, Stefano; Santos, Cristina; Pons, José L

    2014-10-15

    The motor system may rely on a modular organization (muscle synergies activated in time) to execute different tasks. We investigated the common control features of walking and cycling in healthy humans from the perspective of muscle synergies. Three hypotheses were tested: 1) muscle synergies extracted from walking trials are similar to those extracted during cycling; 2) muscle synergies extracted from one of these motor tasks can be used to mathematically reconstruct the electromyographic (EMG) patterns of the other task; 3) muscle synergies of cycling can result from merging synergies of walking. A secondary objective was to identify the speed (and cadence) at which higher similarities emerged. EMG activity from eight muscles of the dominant leg was recorded in eight healthy subjects during walking and cycling at four matched cadences. A factorization technique [nonnegative matrix factorization (NNMF)] was applied to extract individual muscle synergy vectors and the respective activation coefficients behind the global muscular activity of each condition. Results corroborated hypotheses 2 and 3, showing that 1) four synergies from walking and cycling can successfully explain most of the EMG variability of cycling and walking, respectively, and 2) two of four synergies from walking appear to merge together to reconstruct one individual synergy of cycling, with best reconstruction values found for higher speeds. Direct comparison of the muscle synergy vectors of walking and the muscle synergy vectors of cycling (hypothesis 1) produced moderated values of similarity. This study provides supporting evidence for the hypothesis that cycling and walking share common neuromuscular mechanisms.

  15. Validity of the Nike+ device during walking and running.

    PubMed

    Kane, N A; Simmons, M C; John, D; Thompson, D L; Bassett, D R; Basset, D R

    2010-02-01

    We determined the validity of the Nike+ device for estimating speed, distance, and energy expenditure (EE) during walking and running. Twenty trained individuals performed a maximal oxygen uptake test and underwent anthropometric and body composition testing. Each participant was outfitted with a Nike+ sensor inserted into the shoe and an Apple iPod nano. They performed eight 6-min stages on the treadmill, including level walking at 55, 82, and 107 m x min(-1), inclined walking (82 m x min(-1)) at 5 and 10% grades, and level running at 134, 161, and 188 m x min(-1). Speed was measured using a tachometer and EE was measured by indirect calorimetry. Results showed that the Nike+ device overestimated the speed of level walking at 55 m x min(-1) by 20%, underestimated the speed of level walking at 107 m x min(-1) by 12%, but closely estimated the speed of level walking at 82 m x min(-1), and level running at all speeds (p<0.05). Similar results were found for distance. The Nike+ device overestimated the EE of level walking by 18-37%, but closely estimated the EE of level running (p<0.05). In conclusion the Nike+ in-shoe device provided reasonable estimates of speed and distance during level running at the three speeds tested in this study. However, it overestimated EE during level walking and it did not detect the increased cost of inclined locomotion.

  16. Walking adaptability after a stroke and its assessment in clinical settings.

    PubMed

    Balasubramanian, Chitralakshmi K; Clark, David J; Fox, Emily J

    2014-01-01

    Control of walking has been described by a tripartite model consisting of stepping, equilibrium, and adaptability. This review focuses on walking adaptability, which is defined as the ability to modify walking to meet task goals and environmental demands. Walking adaptability is crucial to safe ambulation in the home and community environments and is often severely compromised after a stroke. Yet quantification of walking adaptability after stroke has received relatively little attention in the clinical setting. The objectives of this review were to examine the conceptual challenges for clinical measurement of walking adaptability and summarize the current state of clinical assessment for walking adaptability. We created nine domains of walking adaptability from dimensions of community mobility to address the conceptual challenges in measurement and reviewed performance-based clinical assessments of walking to determine if the assessments measure walking adaptability in these domains. Our literature review suggests the lack of a comprehensive well-tested clinical assessment tool for measuring walking adaptability. Accordingly, recommendations for the development of a comprehensive clinical assessment of walking adaptability after stroke have been presented. Such a clinical assessment will be essential for gauging recovery of walking adaptability with rehabilitation and for motivating novel strategies to enhance recovery of walking adaptability after stroke.

  17. Energy cost of walking with flat feet.

    PubMed

    Otman, S; Basgöze, O; Gökce-Kutsal, Y

    1988-08-01

    A comparative study has been conducted to assess the effects of arch support on oxygen consumption in 20 subjects with flat feet who were generally complaining about fatigue, and also to explore whether their feeling of weariness was objective or not. The resting, walking and final recovery heart rates, blood pressures, and walking oxygen consumption values of the patients with flat feet were measured and calculated and compared to a control group using treadmill and oxygen consumption devices. In stage one the patients did not wear any arch support. Then suitable arch supports were prepared for each patient and in stage two they wore these arch supports. The results did not show any significant difference between the resting heart rates, blood pressure and oxygen consumptions. However, differences in walking heart rate, systolic blood pressure, final recovery heart rate, oxygen consumption, and energy cost values were found to be significant between stage one and two of the test in the patient group. The difference in walking diastolic blood pressure values without and with arch support were found to be insignificant. It may therefore be deduced that oxygen consumption during walking is decreased when a suitable arch support is applied to patients with flat feet.

  18. Gait Pattern Alterations during Walking, Texting and Walking and Texting during Cognitively Distractive Tasks while Negotiating Common Pedestrian Obstacles

    PubMed Central

    Licence, Sammy; Smith, Robynne; McGuigan, Miranda P.; Earnest, Conrad P.

    2015-01-01

    Objectives Mobile phone texting is a common daily occurrence with a paucity of research examining corresponding gait characteristics. To date, most studies have participants walk in a straight line vs. overcoming barriers and obstacles that occur during regular walking. The aim of our study is to examine the effect of mobile phone texting during periods of cognitive distraction while walking and negotiating barriers synonymous with pedestrian traffic. Methods Thirty participants (18-50y) completed three randomized, counter-balanced walking tasks over a course during: (1) normal walking (control), (2) texting and walking, and (3) texting and walking whilst being cognitively distraction via a standard mathematical test performed while negotiating the obstacle course. We analyzed gait characteristics during course negotiation using a 3-dimensional motion analysis system and a general linear model and Dunnet-Hsu post-hoc procedure the normal walking condition to assess gait characteristic differences. Primary outcomes included the overall time to complete the course time and barrier contact. Secondary outcomes included obstacle clearance height, step frequency, step time, double support phase and lateral deviation. Results Participants took significantly longer (mean ± SD) to complete the course while texting (24.96±4.20 sec) and during cognitive distraction COG (24.09±3.36 sec) vs. normal walking (19.32±2.28 sec; all, P<0.001). No significant differences were noted for barrier contacts (P = 0.28). Step frequency, step time, double support phase and lateral deviation all increased in duration during the texting and cognitive distraction trial. Texting and being cognitively distracted also increased obstacle clearance versus the walking condition (all, P<0.02). Conclusions Texting while walking and/or being cognitively distracted significantly affect gait characteristics concordant to mobile phone usage resulting in a more cautious gate pattern. Future research

  19. Detection of Abnormal Muscle Activations during Walking Following Spinal Cord Injury (SCI)

    ERIC Educational Resources Information Center

    Wang, Ping; Low, K. H.; McGregor, Alison H.; Tow, Adela

    2013-01-01

    In order to identify optimal rehabilitation strategies for spinal cord injury (SCI) participants, assessment of impaired walking is required to detect, monitor and quantify movement disorders. In the proposed assessment, ten healthy and seven SCI participants were recruited to perform an over-ground walking test at slow walking speeds. SCI…

  20. [Walking abnormalities in children].

    PubMed

    Segawa, Masaya

    2010-11-01

    Walking is a spontaneous movement termed locomotion that is promoted by activation of antigravity muscles by serotonergic (5HT) neurons. Development of antigravity activity follows 3 developmental epochs of the sleep-wake (S-W) cycle and is modulated by particular 5HT neurons in each epoch. Activation of antigravity activities occurs in the first epoch (around the age of 3 to 4 months) as restriction of atonia in rapid eye movement (REM) stage and development of circadian S-W cycle. These activities strengthen in the second epoch, with modulation of day-time sleep and induction of crawling around the age of 8 months and induction of walking by 1 year. Around the age of 1 year 6 months, absence of guarded walking and interlimb cordination is observed along with modulation of day-time sleep to once in the afternoon. Bipedal walking in upright position occurs in the third epoch, with development of a biphasic S-W cycle by the age of 4-5 years. Patients with infantile autism (IA), Rett syndrome (RTT), or Tourette syndrome (TS) show failure in the development of the first, second, or third epoch, respectively. Patients with IA fail to develop interlimb coordination; those with RTT, crawling and walking; and those with TS, walking in upright posture. Basic pathophysiology underlying these condition is failure in restricting atonia in REM stage; this induces dysfunction of the pedunculopontine nucleus and consequently dys- or hypofunction of the dopamine (DA) neurons. DA hypofunction in the developing brain, associated with compensatory upward regulation of the DA receptors causes psychobehavioral disorders in infancy (IA), failure in synaptogenesis in the frontal cortex and functional development of the motor and associate cortexes in late infancy through the basal ganglia (RTT), and failure in functional development of the prefrontal cortex through the basal ganglia (TS). Further, locomotion failure in early childhood causes failure in development of functional

  1. Effect of Backward Walking on Attention: Possible Application on ADHD

    PubMed Central

    Viggiano, Davide; Travaglio, Michele; Cacciola, Giovanna; Di Costanzo, Alfonso

    2015-01-01

    The human requires attentive effort as assessed in dual-task experiments. Consistently, an attentive task can modify the walking pattern and a attention deficit and hyperactivity disorder (ADHD) is accompanied by gait modifications. Here we investigated the relationships between backward walking and attentive performances in ADHD children (n=13) and healthy age-, height and weight matched controls (n=17). We evaluated the attentive/impulsive profile by means of a Go/No-Go task and the backward and forward gait parameters by step length, cadence and Froude number. Moreover, to test the causal relationship between attention and gait parameters, we trained children to walk backward. The training program consisted of 10 min backward walking session, thrice a week for two months. Results showed a significant negative correlation between Froude number during backward walking and reaction time in the Go/No-Go test. Besides, after training with backward walking control children increased their cadence by 9.3% and their Froude number by 17% during backward walking. Conversely, ADHD children did not modify their walking parameters after training, and showed a significant reduction in their number of errors in the Go/No-Go task (−49%) compared to the score before the training. These data suggest that specific physical training with attention-demanding tasks may improve attentive performance. PMID:25674550

  2. Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators

    PubMed Central

    Holdgate, Matthew R.; Meehan, Cheryl L.; Hogan, Jennifer N.; Miller, Lance J.; Soltis, Joseph; Andrews, Jeff; Shepherdson, David J.

    2016-01-01

    Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare. PMID:27414411

  3. Spin-1 quantum walks

    NASA Astrophysics Data System (ADS)

    Morita, Daichi; Kubo, Toshihiro; Tokura, Yasuhiro; Yamashita, Makoto

    2016-06-01

    We study the quantum walks of two interacting spin-1 bosons. We derive an exact solution for the time-dependent wave function, which describes the two-particle dynamics governed by the one-dimensional spin-1 Bose-Hubbard model. We show that propagation dynamics in real space and mixing dynamics in spin space are correlated via the spin-dependent interaction in this system. The spin-mixing dynamics has two characteristic frequencies in the limit of large spin-dependent interactions. One of the characteristic frequencies is determined by the energy difference between two bound states, and the other frequency relates to the cotunneling process of a pair of spin-1 bosons. Furthermore, we numerically analyze the growth of the spin correlations in quantum walks. We find that long-range spin correlations emerge showing a clear dependence on the sign of the spin-dependent interaction and the initial state.

  4. Tightrope walking bubbles

    NASA Astrophysics Data System (ADS)

    de Maleprade, Helene; Clanet, Christophe; Quere, David

    2016-11-01

    A fiber can hold a certain amount of liquid, which allows us to capture flying drops and control their motion. Immersed in water, a fiber can efficiently capture air bubbles only if it is hydrophobic. Using a superhydrophobic coating on an inclined wire, we experimentally control the rising velocity of air bubbles walking along the tightrope. We discuss the nature of the friction around the walker, and the resulting speed of bubbles.

  5. Training improves walking capacity and cardiovascular function in arteritis.

    PubMed

    Lima, Aluísio H R de A; Lins-Filho, Ozéas L; Soares, Antonio H G; Batista, Rafael M F; Ritti-Dias, Raphael M

    2014-06-01

    Patients with arteritis have a high risk of mortality from cardiovascular disorders. However, whether these patients benefit from an intervention involving exercise remains unclear. In this study, we assessed the effects of an unsupervised exercise program on walking capacity, quality of life, and cardiovascular parameters of a patient with arteritis. A 33-year-old man reporting symptoms of claudication during walking was studied. Imaging tests revealed severe atherosclerosis and arteritis was diagnosed. Five weekly sessions of walking for 16 weeks increased claudication distance and total walking distance, produced improvements in six out of the eight health-related quality-of-life domains, decreased systolic blood pressure, and changed cardiac autonomic modulation toward parasympathetic modulation. This case report showed that unsupervised exercise training improved walking capacity, quality of life, and cardiovascular parameters in a patient with arteritis.

  6. Stilt walking: how do we learn those first steps?

    PubMed

    Akram, Sakineh B; Frank, James S

    2009-09-01

    This study examined how young healthy adults learn stilt walking. Ten healthy male university students attended two sessions of testing held on two consecutive days. In each session participants performed three blocks of 10 stilt-walking trials. Angular movements of head and trunk and the spatial and temporal gait parameters were recorded. When walking on stilts young adults improved their gait velocity through modifications of step parameters while maintaining trunk movements close to that observed during normal over-ground walking. Participants improved their performance by increasing their step frequency and step length and reducing the double support percentage of the gait cycle. Stilts are often used for drywall installation, painting over-the-head areas and raising workers above the ground without the burden of erecting scaffolding. This research examines the locomotor adaptation as young healthy adults learn the complex motor task of stilt walking; a task that is frequently used in the construction industry.

  7. Fractional random walk lattice dynamics

    NASA Astrophysics Data System (ADS)

    Michelitsch, T. M.; Collet, B. A.; Riascos, A. P.; Nowakowski, A. F.; Nicolleau, F. C. G. A.

    2017-02-01

    We analyze time-discrete and time-continuous ‘fractional’ random walks on undirected regular networks with special focus on cubic periodic lattices in n  =  1, 2, 3,.. dimensions. The fractional random walk dynamics is governed by a master equation involving fractional powers of Laplacian matrices {{L}\\fracα{2}}} where α =2 recovers the normal walk. First we demonstrate that the interval 0<α ≤slant 2 is admissible for the fractional random walk. We derive analytical expressions for the transition matrix of the fractional random walk and closely related the average return probabilities. We further obtain the fundamental matrix {{Z}(α )} , and the mean relaxation time (Kemeny constant) for the fractional random walk. The representation for the fundamental matrix {{Z}(α )} relates fractional random walks with normal random walks. We show that the matrix elements of the transition matrix of the fractional random walk exihibit for large cubic n-dimensional lattices a power law decay of an n-dimensional infinite space Riesz fractional derivative type indicating emergence of Lévy flights. As a further footprint of Lévy flights in the n-dimensional space, the transition matrix and return probabilities of the fractional random walk are dominated for large times t by slowly relaxing long-wave modes leading to a characteristic {{t}-\\frac{n{α}} -decay. It can be concluded that, due to long range moves of fractional random walk, a small world property is emerging increasing the efficiency to explore the lattice when instead of a normal random walk a fractional random walk is chosen.

  8. An exploration of impaired walking dynamics and fatigue in Multiple Sclerosis

    PubMed Central

    2012-01-01

    Background Physical disability in multiple sclerosis (MS) is frequently characterized by impaired ambulation. Although walking tests have been successfully employed to assess walking ability in MS patients, data analytic procedures have predominantly relied on result-oriented parameters (e.g. total distance covered during a given amount of time), whereas process-oriented, dynamic walking patterns have mostly been ignored. This is striking, since healthy individuals have been observed to display a stereotypical U-shaped pattern of walking speed during timed walking, characterized by relatively high speed during the initial phase, subsequent slowing and final acceleration. Objective of the current study was to test the utility of the 6 min Walk (6MW) and the 12 min Walk (12MW) for revealing putatively abnormal temporal dynamic features of walking in MS. Methods A group of 37 MS patients was divided into subgroups with regard to their level of disability analyzed with the Expanded Disability Status Scale (EDSS; Mild MS Group, n = 20, EDSS 0 – 3.5; Moderate MS Group, n = 17, EDSS 4 – 5). Subsequently, both groups were compared to age-matched healthy controls (n = 25) on both tests with regard to result-oriented characteristics (mean walking speed), as well as dynamic features (mean decline in walking speed, degree of observed U-shape). Results Both MS groups showed a significantly lower mean walking speed than healthy controls, independent of test duration. Compared to controls, the Moderate MS Group also slowed down more rapidly throughout both tests. The same pronounced decline in walking speed was observed for the Mild MS Group in case of the 12MW. Additionally, for both MS groups an attenuated U-shaped velocity pattern was observed relative to controls in the 6MW. Patients' subjective fatigue scores were more strongly correlated with the decline in walking speed than with the common parameter of mean walking speed in the 6MW. Conclusions MS patients

  9. New wearable walking-type continuous passive motion device for postsurgery walking rehabilitation.

    PubMed

    Zhu, Yong; Nakamura, Masahiro; Horiuchi, Tadahiro; Kohno, Hideki; Takahashi, Rei; Terada, Hidetsugu; Haro, Hirotaka

    2013-07-01

    While total knee arthroplasty is useful for treating osteoarthritis of the knee, the success of this treatment depends on effective rehabilitation. The goal of this study was to develop an assistive device for post-total knee arthroplasty patients for walking rehabilitation and for shortening the hospitalization period. We developed a brace electronic assist system termed the knee assistive instrument for walking rehabilitation (KAI-R) to illustrate the need for training during postoperative rehabilitation. Sixteen osteoarthritis patients (1 male and 15 females; average age 68.9 years) who underwent total knee arthroplasty were analyzed before operation and 2-4 weeks after operation, and 25 healthy individuals (14 males and 11 females; average age 26.2 years) formed the control group. Based on the pre- and postoperative data on peak knee flexion angle, foot height, and walking velocity, we developed the KAI-R, which consists of an assistive mechanism for the knee joint, a hip joint support system, and a foot pressure sensor system and is driven by a CPU board that generates the walking pattern. We then tested the walking gait in seven healthy volunteers with and without KAI-R assistance. KAI-R increased the peak flexion angle of the knee and foot height in all seven volunteers; their range of motion of the knee joint was increased. However, KAI-R also decreased the walking velocity of subjects, which was explained by reaction delay and slightly compromised physical balance, which was caused by wearing the KAI-R. KAI-R is useful for gait improvement. In future studies, KAI-R will be investigated in a clinical trial for its ability for walking rehabilitation in post-total knee arthroplasty patients.

  10. The experimental study on the contact process of passive walking

    NASA Astrophysics Data System (ADS)

    Qi, Feng; Bi, Lai-Ye; Wang, Tian-Shu; Li, Jun-Feng

    2012-08-01

    The passive dynamic walking is a new concept of biped walking. Researchers have been working on this area with both theoretical analysis and experimental analysis ever since McGeer. This paper presents our compass-like passive walking model with a new set of testing system. Two gyroscopes are used for measuring the angles of two legs, and ten FlexiForce sensors are used for measuring the contact forces on the feet. We got the experimental data on the passive walking process with the validated testing system. A great emphasis was put on the contact process between the feet and the slope. The contact process of the stance leg was divided into four sections, and differences between the real testing contact process and the classic analytical contact process with no bouncing and slipping were summarized.

  11. Persistence of random walk records

    NASA Astrophysics Data System (ADS)

    Ben-Naim, E.; Krapivsky, P. L.

    2014-06-01

    We study records generated by Brownian particles in one dimension. Specifically, we investigate an ordinary random walk and define the record as the maximal position of the walk. We compare the record of an individual random walk with the mean record, obtained as an average over infinitely many realizations. We term the walk ‘superior’ if the record is always above average, and conversely, the walk is said to be ‘inferior’ if the record is always below average. We find that the fraction of superior walks, S, decays algebraically with time, S ˜ t-β, in the limit t → ∞, and that the persistence exponent is nontrivial, β = 0.382 258…. The fraction of inferior walks, I, also decays as a power law, I ˜ t-α, but the persistence exponent is smaller, α = 0.241 608…. Both exponents are roots of transcendental equations involving the parabolic cylinder function. To obtain these theoretical results, we analyze the joint density of superior walks with a given record and position, while for inferior walks it suffices to study the density as a function of position.

  12. Walking Machine Control Programming

    DTIC Science & Technology

    1983-08-31

    difficulty. 21 \\W;dkitiI M.’h 1 .(otri rot I’rogr ii ini g S A #2054 iI.Ld T’dl itdt Itort OWL WALKING ALGORITHMS The structure of the nervous system of...the nervous system . For this reason the cell it is usually attached to the ad- perpendicular axes and about acoustic the hair cell is sometimes...to drive air from the hydraulic system is to drive the compensator in while the ma- chine is tucked. The knee centering routine simply positions the

  13. Agile Walking Robot

    NASA Technical Reports Server (NTRS)

    Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.; Waldron, Kenneth J.

    1990-01-01

    Proposed agile walking robot operates over rocky, sandy, and sloping terrain. Offers stability and climbing ability superior to other conceptual mobile robots. Equipped with six articulated legs like those of insect, continually feels ground under leg before applying weight to it. If leg sensed unexpected object or failed to make contact with ground at expected point, seeks alternative position within radius of 20 cm. Failing that, robot halts, examines area around foot in detail with laser ranging imager, and replans entire cycle of steps for all legs before proceeding.

  14. Rugged Walking Robot

    NASA Technical Reports Server (NTRS)

    Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

    1990-01-01

    Proposed walking-beam robot simpler and more rugged than articulated-leg walkers. Requires less data processing, and uses power more efficiently. Includes pair of tripods, one nested in other. Inner tripod holds power supplies, communication equipment, computers, instrumentation, sampling arms, and articulated sensor turrets. Outer tripod holds mast on which antennas for communication with remote control site and video cameras for viewing local and distant terrain mounted. Propels itself by raising, translating, and lowering tripods in alternation. Steers itself by rotating raised tripod on turntable.

  15. Sunspot random walk and 22-year variation

    USGS Publications Warehouse

    Love, Jeffrey J.; Rigler, E. Joshua

    2012-01-01

    We examine two stochastic models for consistency with observed long-term secular trends in sunspot number and a faint, but semi-persistent, 22-yr signal: (1) a null hypothesis, a simple one-parameter random-walk model of sunspot-number cycle-to-cycle change, and, (2) an alternative hypothesis, a two-parameter random-walk model with an imposed 22-yr alternating amplitude. The observed secular trend in sunspots, seen from solar cycle 5 to 23, would not be an unlikely result of the accumulation of multiple random-walk steps. Statistical tests show that a 22-yr signal can be resolved in historical sunspot data; that is, the probability is low that it would be realized from random data. On the other hand, the 22-yr signal has a small amplitude compared to random variation, and so it has a relatively small effect on sunspot predictions. Many published predictions for cycle 24 sunspots fall within the dispersion of previous cycle-to-cycle sunspot differences. The probability is low that the Sun will, with the accumulation of random steps over the next few cycles, walk down to a Dalton-like minimum. Our models support published interpretations of sunspot secular variation and 22-yr variation resulting from cycle-to-cycle accumulation of dynamo-generated magnetic energy.

  16. Autonomous exoskeleton reduces metabolic cost of walking.

    PubMed

    Mooney, Luke M; Rouse, Elliott J; Herr, Hugh M

    2014-01-01

    We developed an autonomous powered leg exoskeleton capable of providing large amounts of positive mechanical power to the wearer during powered plantarflexion phase of walking. The autonomous exoskeleton consisted of a winch actuator fasted to the shin which pulled on fiberglass struts attached to a boot. The fiberglass struts formed a rigid extension of the foot when the proximal end of the strut was pulled in forward by the winch actuator. This lightweight, geometric transmission allowed the electric winch actuator to efficiently produce biological levels of power at the ankle joint. The exoskeleton was powered and controlled by lithium polymer batteries and motor controller worn around the waist. Preliminary testing on two subjects walking at 1.4 m/s resulted in the exoskeleton reducing the metabolic cost of walking by 6-11% as compared to not wearing the device. The exoskeleton provided a peak mechanical power of over 180 W at each ankle (mean standard ± deviation) and an average positive mechanical power of 27 ± 1 W total to both ankles, while electrically using 75-89 W of electricity. The batteries (800 g) used in this experiment are estimated to be capable of providing this level of assistance for up to 7 km of walking.

  17. Random-walk enzymes.

    PubMed

    Mak, Chi H; Pham, Phuong; Afif, Samir A; Goodman, Myron F

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C→U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  18. Random-walk enzymes

    PubMed Central

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-01-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C → U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics. PMID:26465508

  19. Random-walk enzymes

    NASA Astrophysics Data System (ADS)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  20. Effects of cognitive and motor tasks on the walking speed of individuals with chronic stroke

    PubMed Central

    Goh, Lee-Yin.; Tan, Isaac O.; Yang, Li C.; Ng, Shamay S.M.

    2017-01-01

    Abstract Walking speed is a measure of gait performance after a stroke and a predictor of community ambulatory competence. Although gait decrements during a cognitive or motor task after stroke are well-documented, the differential effects of motor and cognitive tasks on the comfortable and maximum walking speeds of individuals with chronic stroke have not been investigated. This study aimed to compare the effects of cognitive and motor tasks on the comfortable and maximum walking speeds of individuals with chronic stroke. This is a cross-sectional study. Thirty community-dwelling chronic stroke individuals were included. Time taken to complete the 10-meter Walk Test under various conditions, including walking alone, walking while completing a cognitive task, and walking while completing a motor task, was recorded, with each condition performed at comfortable as well as maximum walking speeds. Accuracy in performing the cognitive tasks was also assessed. The cognitive and motor tasks caused decrements in both comfortable and maximum walking speeds (P ≤ 0.001). The cognitive task had a greater influence than the motor task on maximum walking speed (P < 0.01). Individuals with chronic stroke tend to prioritize task accuracy and completion over maintaining walking speed. This phenomenon was more evident during the cognitive task than the motor task and was especially evident at maximum walking speed. PMID:28248885

  1. 40 CFR 60.275 - Test methods and procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Electric Arc Furnaces Constructed After October 21, 1974, and On or Before August 17, 1983 § 60.275 Test... conducted at least once per day for at least three 6-minute periods when the furnace is operating in...

  2. 40 CFR 60.275 - Test methods and procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Electric Arc Furnaces Constructed After October 21, 1974, and On or Before August 17, 1983 § 60.275 Test... conducted at least once per day for at least three 6-minute periods when the furnace is operating in...

  3. 40 CFR 60.275 - Test methods and procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Electric Arc Furnaces Constructed After October 21, 1974, and On or Before August 17, 1983 § 60.275 Test... conducted at least once per day for at least three 6-minute periods when the furnace is operating in...

  4. 40 CFR 60.275 - Test methods and procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Electric Arc Furnaces Constructed After October 21, 1974, and On or Before August 17, 1983 § 60.275 Test... conducted at least once per day for at least three 6-minute periods when the furnace is operating in...

  5. 40 CFR 60.275 - Test methods and procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Electric Arc Furnaces Constructed After October 21, 1974, and On or Before August 17, 1983 § 60.275 Test... conducted at least once per day for at least three 6-minute periods when the furnace is operating in...

  6. Analysis of Balance during Functional Walking in Stroke Survivors

    PubMed Central

    Weenk, Dirk; van Asseldonk, Edwin H. F.; Schepers, H. Martin; Veltink, Peter H.; Buurke, Jaap H.

    2016-01-01

    Background An important objective of rehabilitation care is to regain adequate balance function to safely ambulate in community. However, in rehabilitation practice, it remains unclear if a stroke survivor functionally recovers by restitution or by learning to compensate for the lack of restoration of body function. Aim of this study is to propose and evaluate methods for the objective evaluation of balance during functional walking in stroke survivors. Methods Stroke survivors performed twice a Timed “Up & Go” (TUG) test. Ground reaction forces and position changes of both feet were measured using instrumented shoes and used to estimate the position of the center of mass (CoM). Balance control and efficiency metrics were defined to evaluate functional walking under variable conditions. Metrics were corrected based on the instantaneous velocity direction of CoM. Intra- and inter-participant variations for different phases of the TUG test were examined. Metrics were related to the Berg balance scale (BBS). Results Participants with higher BBS scores show a more efficient walking pattern. Their walking velocity and walking direction is less variable and they are more frequently unstable when walking in a straight line or when turning. Furthermore, the less affected participants are able to move their CoM more towards their affected side. Discussion We developed and demonstrated a method to assess walking balance of stroke survivors. System design and evaluation methods allow balance evaluation during functional walking in daily life. Some presented metrics show correlations with BBS scores. Clear inter- and intra-patient variations in metric values are present that cannot be explained by BBS scores, which supports the additional value of the presented system. Presented methods may be used for objective evaluation of restitution and compensation of walking balance and have a potential application in individual evidence-based therapy. PMID:27855211

  7. Characterisation of walking loads by 3D inertial motion tracking

    NASA Astrophysics Data System (ADS)

    Van Nimmen, K.; Lombaert, G.; Jonkers, I.; De Roeck, G.; Van den Broeck, P.

    2014-09-01

    The present contribution analyses the walking behaviour of pedestrians in situ by 3D inertial motion tracking. The technique is first tested in laboratory experiments with simultaneous registration of the ground reaction forces. The registered motion of the pedestrian allows for the identification of stride-to-stride variations, which is usually disregarded in the simulation of walking forces. Subsequently, motion tracking is used to register the walking behaviour of (groups of) pedestrians during in situ measurements on a footbridge. The calibrated numerical model of the structure and the information gathered using the motion tracking system enables detailed simulation of the step-by-step pedestrian induced vibrations. Accounting for the in situ identified walking variability of the test-subjects leads to a significantly improved agreement between the measured and the simulated structural response.

  8. Modeling spatial segregation and travel cost influences on utilitarian walking: Towards policy intervention.

    PubMed

    Yang, Yong; Auchincloss, Amy H; Rodriguez, Daniel A; Brown, Daniel G; Riolo, Rick; Diez-Roux, Ana V

    2015-05-01

    We develop an agent-based model of utilitarian walking and use the model to explore spatial and socioeconomic factors affecting adult utilitarian walking and how travel costs as well as various educational interventions aimed at changing attitudes can alter the prevalence of walking and income differentials in walking. The model is validated against US national data. We contrast realistic and extreme parameter values in our model and test effects of changing these parameters across various segregation and pricing scenarios while allowing for interactions between travel choice and place and for behavioral feedbacks. Results suggest that in addition to income differences in the perceived cost of time, the concentration of mixed land use (differential density of residences and businesses) are important determinants of income differences in walking (high income walk less), whereas safety from crime and income segregation on their own do not have large influences on income differences in walking. We also show the difficulty in altering walking behaviors for higher income groups who are insensitive to price and how adding to the cost of driving could increase the income differential in walking particularly in the context of segregation by income and land use. We show that strategies to decrease positive attitudes towards driving can interact synergistically with shifting cost structures to favor walking in increasing the percent of walking trips. Agent-based models, with their ability to capture dynamic processes and incorporate empirical data, are powerful tools to explore the influence on health behavior from multiple factors and test policy interventions.

  9. Quantum walks on quotient graphs

    SciTech Connect

    Krovi, Hari; Brun, Todd A.

    2007-06-15

    A discrete-time quantum walk on a graph {gamma} is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. If this unitary evolution operator has an associated group of symmetries, then for certain initial states the walk will be confined to a subspace of the original Hilbert space. Symmetries of the original graph, given by its automorphism group, can be inherited by the evolution operator. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph. We give an explicit construction of the quotient graph for any subgroup H of the automorphism group and illustrate it with examples. The automorphisms of the quotient graph which are inherited from the original graph are the original automorphism group modulo the subgroup H used to construct it. The quotient graph is constructed by removing the symmetries of the subgroup H from the original graph. We then analyze the behavior of hitting times on quotient graphs. Hitting time is the average time it takes a walk to reach a given final vertex from a given initial vertex. It has been shown in earlier work [Phys. Rev. A 74, 042334 (2006)] that the hitting time for certain initial states of a quantum walks can be infinite, in contrast to classical random walks. We give a condition which determines whether the quotient graph has infinite hitting times given that they exist in the original graph. We apply this condition for the examples discussed and determine which quotient graphs have infinite hitting times. All known examples of quantum walks with hitting times which are short compared to classical random walks correspond to systems with quotient graphs much smaller than the original graph; we conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speedup.

  10. Walking indoors, walking outdoors: an fMRI study

    PubMed Central

    Dalla Volta, Riccardo; Fasano, Fabrizio; Cerasa, Antonio; Mangone, Graziella; Quattrone, Aldo; Buccino, Giovanni

    2015-01-01

    An observation/execution matching system for walking has not been assessed yet. The present fMRI study was aimed at assessing whether, as for object-directed actions, an observation/execution matching system is active for walking and whether the spatial context of walking (open or narrow space) recruits different neural correlates. Two experimental conditions were employed. In the execution condition, while being scanned, participants performed walking on a rolling cylinder located just outside the scanner. The same action was performed also while observing a video presenting either an open space (a country field) or a narrow space (a corridor). In the observation condition, participants observed a video presenting an individual walking on the same cylinder on which the actual action was executed, the open space video and the narrow space video, respectively. Results showed common bilateral activations in the dorsal premotor/supplementary motor areas and in the posterior parietal lobe for both execution and observation of walking, thus supporting a matching system for this action. Moreover, specific sectors of the occipital–temporal cortex and the middle temporal gyrus were consistently active when processing a narrow space versus an open one, thus suggesting their involvement in the visuo-motor transformation required when walking in a narrow space. We forward that the present findings may have implications for rehabilitation of gait and sport training. PMID:26483745

  11. Slow-walking inflation

    SciTech Connect

    Erdmenger, Johanna; Halter, Sebastian; Núñez, Carlos; Tasinato, Gianmassimo E-mail: s.halter@physik.uni-muenchen.de E-mail: gianmassimo.tasinato@port.ac.uk

    2013-01-01

    We propose a new model of slow-roll inflation in string cosmology, based on warped throat supergravity solutions displaying 'walking' dynamics, i.e. the coupling constant of the dual gauge theory slowly varies over a range of energy scales. The features of the throat geometry are sourced by a rich field content, given by the dilaton and RR and NS fluxes. By considering the motion of a D3-brane probe in this geometry, we are able to analytically calculate the brane potential in a physically interesting regime. This potential has an inflection point: in its proximity we realize a model of inflation lasting sixty e-foldings, and whose robust predictions are in agreement with current observations. We are also able to interpret some of the most interesting aspects of this scenario in terms of the properties of the QFT dual theory.

  12. Diffraction of walking droplets

    NASA Astrophysics Data System (ADS)

    Harris, Daniel M.; Pucci, Giuseppe; Bush, John W. M.

    2014-11-01

    We present results from our revisitation of the experiment of a walking droplet passing through a single slit, originally investigated by Couder & Fort (PRL, 2006). On each passage, the walker's trajectory is deviated as a result of the spatial confinement of its guiding wave. We explore the role of the droplet size and the bath's vibration amplitude on both the dynamics and statistics. We find the behavior to be remarkably sensitive to these control parameters. A complex physical picture emerges. The authors gratefully acknowledge the financial support of the NSF through Grant CMMI-1333242, DMH through the NSF Graduate Research Fellowship Program, and GP through the Programma Operativo Regionale (POR) Calabria - FSE 2007/2013.

  13. Water-walking devices

    NASA Astrophysics Data System (ADS)

    Hu, David L.; Prakash, Manu; Chan, Brian; Bush, John W. M.

    2007-11-01

    We report recent efforts in the design and construction of water-walking machines inspired by insects and spiders. The fundamental physical constraints on the size, proportion and dynamics of natural water-walkers are enumerated and used as design criteria for analogous mechanical devices. We report devices capable of rowing along the surface, leaping off the surface and climbing menisci by deforming the free surface. The most critical design constraint is that the devices be lightweight and non-wetting. Microscale manufacturing techniques and new man-made materials such as hydrophobic coatings and thermally actuated wires are implemented. Using high-speed cinematography and flow visualization, we compare the functionality and dynamics of our devices with those of their natural counterparts.

  14. Water-walking devices

    NASA Astrophysics Data System (ADS)

    Hu, David L.; Prakash, Manu; Chan, Brian; Bush, John W. M.

    We report recent efforts in the design and construction of water-walking machines inspired by insects and spiders. The fundamental physical constraints on the size, proportion and dynamics of natural water-walkers are enumerated and used as design criteria for analogous mechanical devices. We report devices capable of rowing along the surface, leaping off the surface and climbing menisci by deforming the free surface. The most critical design constraint is that the devices be lightweight and non-wetting. Microscale manufacturing techniques and new man-made materials such as hydrophobic coatings and thermally actuated wires are implemented. Using highspeed cinematography and flow visualization, we compare the functionality and dynamics of our devices with those of their natural counterparts.

  15. Numerical and Analytic Studies of Random-Walk Models.

    NASA Astrophysics Data System (ADS)

    Li, Bin

    We begin by recapitulating the universality approach to problems associated with critical systems, and discussing the role that random-walk models play in the study of phase transitions and critical phenomena. As our first numerical simulation project, we perform high-precision Monte Carlo calculations for the exponents of the intersection probability of pairs and triplets of ordinary random walks in 2 dimensions, in order to test the conformal-invariance theory predictions. Our numerical results strongly support the theory. Our second numerical project aims to test the hyperscaling relation dnu = 2 Delta_4-gamma for self-avoiding walks in 2 and 3 dimensions. We apply the pivot method to generate pairs of self-avoiding walks, and then for each pair, using the Karp-Luby algorithm, perform an inner -loop Monte Carlo calculation of the number of different translates of one walk that makes at least one intersection with the other. Applying a least-squares fit to estimate the exponents, we have obtained strong numerical evidence that the hyperscaling relation is true in 3 dimensions. Our great amount of data for walks of unprecedented length(up to 80000 steps), yield a updated value for the end-to-end distance and radius of gyration exponent nu = 0.588 +/- 0.001 (95% confidence limit), which comes out in good agreement with the renormalization -group prediction. In an analytic study of random-walk models, we introduce multi-colored random-walk models and generalize the Symanzik and B.F.S. random-walk representations to the multi-colored case. We prove that the zero-component lambdavarphi^2psi^2 theory can be represented by a two-color mutually -repelling random-walk model, and it becomes the mutually -avoiding walk model in the limit lambda to infty. However, our main concern and major break-through lies in the study of the two-point correlation function for the lambda varphi^2psi^2 theory with N > 0 components. By representing it as a two-color random-walk expansion

  16. Constraining walking and custodial technicolor

    SciTech Connect

    Foadi, Roshan; Frandsen, Mads T.; Sannino, Francesco

    2008-05-01

    We show how to constrain the physical spectrum of walking technicolor models via precision measurements and modified Weinberg sum rules. We also study models possessing a custodial symmetry for the S parameter at the effective Lagrangian level - custodial technicolor - and argue that these models cannot emerge from walking-type dynamics. We suggest that it is possible to have a very light spin-one axial (vector) boson. However, in the walking dynamics the associated vector boson is heavy while it is degenerate with the axial in custodial technicolor.

  17. Walking while memorizing: age-related differences in compensatory behavior.

    PubMed

    Li, K Z; Lindenberger, U; Freund, A M; Baltes, P B

    2001-05-01

    This study investigated predictions of the life-span theory of selection, optimization, and compensation, focusing on different patterns of task priority during dual-task performance in younger and older adults. Cognitive (memorizing) and sensorimotor (walking a narrow track) performance were measured singly, concurrently, and when task difficulty was manipulated. Use of external aids was measured to provide another index of task priority. Before dual-task testing, participants received extensive training with each component task and external aid. Age differences in dual-task costs were greater in memory performance than walking, suggesting that older adults prioritized walking over memory. Further, when given a choice of compensatory external aids to use, older adults optimized walking, whereas younger adults optimized memory performance. The results have broad implications for systemic theories of cognitive and sensorimotor aging, and the costs and benefits of assistive devices and environmental support for older populations.

  18. Stair-Walking Performance in Adolescents with Intellectual Disabilities

    PubMed Central

    Shieh, Wann-Yun; Ju, Yan-Ying; Yu, Yu-Chun; Lin, Che-Kuan; Lin, Yen-Tzu; Cheng, Hsin-Yi Kathy

    2016-01-01

    Most individuals with intellectual disabilities (ID) demonstrate problems in learning and movement coordination. Consequently, they usually have difficulties in activities such as standing, walking, and stair climbing. To monitor the physical impairments of these children, regular gross motor evaluation is crucial. Straight-line level walking is the most frequently used test of their mobility. However, numerous studies have found that unless the children have multiple disabilities, no significant differences can be found between the children with ID and typically-developed children in this test. Stair climbing presents more challenges than level walking because it is associated with numerous physical factors, including lower extremity strength, cardiopulmonary endurance, vision, balance, and fear of falling. Limited ability in those factors is one of the most vital markers for children with ID. In this paper, we propose a sensor-based approach for measuring stair-walking performance, both upstairs and downstairs, for adolescents with ID. Particularly, we address the problem of sensor calibration to ensure measurement accuracy. In total, 62 participants aged 15 to 21 years, namely 32 typically-developed (TD) adolescents, 20 adolescents with ID, and 10 adolescents with multiple disabilities (MD), participated. The experimental results showed that stair-walking is more sensitive than straight-line level walking in capturing gait characteristics for adolescents with ID. PMID:27409621

  19. Base Station Walk-Back

    NASA Video Gallery

    Train to improve your lung, heart, and other muscle endurance while walking a progressive, measured distance. The Train Like an Astronaut project uses the excitement of exploration to challenge stu...

  20. Quantum snake walk on graphs

    SciTech Connect

    Rosmanis, Ansis

    2011-02-15

    I introduce a continuous-time quantum walk on graphs called the quantum snake walk, the basis states of which are fixed-length paths (snakes) in the underlying graph. First, I analyze the quantum snake walk on the line, and I show that, even though most states stay localized throughout the evolution, there are specific states that most likely move on the line as wave packets with momentum inversely proportional to the length of the snake. Next, I discuss how an algorithm based on the quantum snake walk might potentially be able to solve an extended version of the glued trees problem, which asks to find a path connecting both roots of the glued trees graph. To the best of my knowledge, no efficient quantum algorithm solving this problem is known yet.

  1. Integrated photonic quantum walks

    NASA Astrophysics Data System (ADS)

    Gräfe, Markus; Heilmann, René; Lebugle, Maxime; Guzman-Silva, Diego; Perez-Leija, Armando; Szameit, Alexander

    2016-10-01

    Over the last 20 years quantum walks (QWs) have gained increasing interest in the field of quantum information science and processing. In contrast to classical walkers, quantum objects exhibit intrinsic properties like non-locality and non-classical many-particle correlations, which renders QWs a versatile tool for quantum simulation and computation as well as for a deeper understanding of genuine quantum mechanics. Since they are highly controllable and hardly interact with their environment, photons seem to be ideally suited quantum walkers. In order to study and exploit photonic QWs, lattice structures that allow low loss coherent evolution of quantum states are demanded. Such requirements are perfectly met by integrated optical waveguide devices that additionally allow a substantial miniaturization of experimental settings. Moreover, by utilizing the femtosecond direct laser writing technique three-dimensional waveguide structures are capable of analyzing QWs also on higher dimensional geometries. In this context, advances and findings of photonic QWs are discussed in this review. Various concepts and experimental results are presented covering, such as different quantum transport regimes, the Boson sampling problem, and the discrete fractional quantum Fourier transform.

  2. Big power from walking

    NASA Astrophysics Data System (ADS)

    Illenberger, Patrin K.; Madawala, Udaya K.; Anderson, Iain A.

    2016-04-01

    Dielectric Elastomer Generators (DEG) offer an opportunity to capture the energy otherwise wasted from human motion. By integrating a DEG into the heel of standard footwear, it is possible to harness this energy to power portable devices. DEGs require substantial auxiliary systems which are commonly large, heavy and inefficient. A unique challenge for these low power generators is the combination of high voltage and low current. A void exists in the semiconductor market for devices that can meet these requirements. Until these become available, existing devices must be used in an innovative way to produce an effective DEG system. Existing systems such as the Bi-Directional Flyback (BDFB) and Self Priming Circuit (SPC) are an excellent example of this. The BDFB allows full charging and discharging of the DEG, improving power gained. The SPC allows fully passive voltage boosting, removing the priming source and simplifying the electronics. This paper outlines the drawbacks and benefits of active and passive electronic solutions for maximizing power from walking.

  3. Technicolor walks at the LHC

    SciTech Connect

    Belyaev, Alexander; Foadi, Roshan; Frandsen, Mads T.; Jaervinen, Matti; Sannino, Francesco; Pukhov, Alexander

    2009-02-01

    We analyze the potential of the Large Hadron Collider (LHC) to observe signatures of phenomenologically viable walking technicolor models. We study and compare the Drell-Yan and vector boson fusion mechanisms for the production of composite heavy vectors. We find that the heavy vectors are most easily produced and detected via the Drell-Yan processes. The composite Higgs phenomenology is also studied. If technicolor walks at the LHC, its footprints will be visible and our analysis will help in uncovering them.

  4. 10 CFR 429.53 - Walk-in coolers and walk-in freezers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Walk-in coolers and walk-in freezers. 429.53 Section 429... CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.53 Walk-in coolers and walk... are applicable to walk-in coolers and freezers; and (2) (b) Certification reports. (1) Except...

  5. 10 CFR 429.53 - Walk-in coolers and walk-in freezers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Walk-in coolers and walk-in freezers. 429.53 Section 429... CONSUMER PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT Certification § 429.53 Walk-in coolers and walk... are applicable to walk-in coolers and freezers; and (2) (b) Certification reports. (1) Except...

  6. The variability problem of normal human walking.

    PubMed

    Simonsen, Erik B; Alkjær, Tine

    2012-03-01

    Previous investigations have suggested considerable inter-individual variability in the time course pattern of net joint moments during normal human walking, although the limited sample sizes precluded statistical analyses. The purpose of the present study was to obtain joint moment patterns from a group of normal subjects and to test whether or not the expected differences would prove to be statistically significant. Fifteen healthy male subjects were recorded on video while they walked across two force platforms. Ten kinematic and kinetic parameters were selected and input to a statistical cluster analysis to determine whether or not the 15 subjects could be divided into different 'families' (clusters) of walking strategy. The net joint moments showed a variability corroborating earlier reports. The cluster analysis showed that the 15 subjects could be grouped into two clusters of 5 and 10 subjects, respectively. Five parameters differed significantly, so the group of 5 subjects was characterized by (1) a higher peak knee joint extensor moment, (2) more flexed knee joint angle at heel strike, (3) during the whole stance phase, (4) lower peak knee joint flexor moment and (5) lower ankle joint angle at flat foot position. Calculation of bone-on-bone forces in the knee joint showed a value of 64 N/kg body weight in the K+ group and 55 N/kg in the K- group (p<0.05). It is unknown if differences of similar magnitude contribute to early joint degeneration in some individuals while not in others.

  7. Visual Evoked Responses During Standing and Walking

    PubMed Central

    Gramann, Klaus; Gwin, Joseph T.; Bigdely-Shamlo, Nima; Ferris, Daniel P.; Makeig, Scott

    2010-01-01

    Human cognition has been shaped both by our body structure and by its complex interactions with its environment. Our cognition is thus inextricably linked to our own and others’ motor behavior. To model brain activity associated with natural cognition, we propose recording the concurrent brain dynamics and body movements of human subjects performing normal actions. Here we tested the feasibility of such a mobile brain/body (MoBI) imaging approach by recording high-density electroencephalographic (EEG) activity and body movements of subjects standing or walking on a treadmill while performing a visual oddball response task. Independent component analysis of the EEG data revealed visual event-related potentials that during standing, slow walking, and fast walking did not differ across movement conditions, demonstrating the viability of recording brain activity accompanying cognitive processes during whole body movement. Non-invasive and relatively low-cost MoBI studies of normal, motivated actions might improve understanding of interactions between brain and body dynamics leading to more complete biological models of cognition. PMID:21267424

  8. Walking speed and distance in different environments of subjects in the later stage post-stroke.

    PubMed

    Carvalho, Cristiane; Sunnerhagen, Katharina S; Willén, Carin

    2010-11-01

    The purpose of this study is to assess short- and long-distance walking performance in indoor and outdoor environments of slow and fast walkers' subjects living in the community in the later stage post-stroke. Thirty-six subjects with at least 6 months post-stroke were included and divided into two groups based on their walking speed in the clinical setting. Thirty-meter walk tests (30 mWT) at self-selected and maximum speeds were assessed in three environments: (1) clinical setting; (2) basement setting; and (3) outdoor setting. Six-minute walk test (6 MWT) distance was assessed in the clinical and outdoor settings. The differences between the 30 mWT and the 6 MWT, as measured by the actual distance obtained in the 6 MWT and the predicted distance calculated for the 30 mWT, were also investigated. There was no difference in walking speed when subjects performed short-distance walking in different environments. However, a difference was found in performance of long-distance walking. Subjects who walked 0.8 m/s or faster also walked further in the outdoor setting. The findings of our study demonstrate that in those who scored below 0.8 m/s, performance of short- and long-distance walking evaluated in an indoor environment reflects the results obtained in an outdoor environment. However, for subjects post-stroke who score 0.8 m/s or faster, distance was increased in the outdoor environments during long-distance walking. Walking speed obtained over a short distance seemed to overestimate long-distance walking capacity for the slow walkers, despite the environment.

  9. Plantar pressures during level walking compared with other ambulatory activities.

    PubMed

    Lundeen, S; Lundquist, K; Cornwall, M W; McPoil, T G

    1994-06-01

    This study was designed to determine the magnitude of plantar pressures during level walking in comparison to other activities. These activities included climbing up stairs, going down stairs, a simple pivot while walking, and a crossover pivot while walking in normal individuals. Twelve volunteers, six men and six women, mean age 28 years, served as subjects. Data were collected on the dominant foot with an EMED-SF pressure sensor platform as each subject walked barefoot and did each of the five activities. Maximum plantar pressure (MPP) and pressure-time integral (PTI) was found in the metatarsal and heel regions. The results of repeated-measures analysis of variance tests showed that the five experimental conditions were statistically different for both MPP and PTI in the metatarsal and heel regions. Post hoc analysis indicated that MPP and PTI were decreased during the going down stairs condition in the heel and increased during the crossover pivot while walking and pivot while walking conditions for the metatarsal region.

  10. Comparison of forward walking and backward walking in stroke hemiplegia patients focusing on the paretic side

    PubMed Central

    Makino, Misato; Takami, Akiyoshi; Oda, Atsushi

    2017-01-01

    [Purpose] To investigate the features of backward walking in stroke patients with hemiplegia by focusing on the joint movements and moments of the paretic side, walking speed, stride length, and cadence. [Subjects and Methods] Nine stroke patients performed forward walking and backward walking along a 5-m walkway. Walking speed and stride length were self-selected. Movements were measured using a three-dimensional motion analysis system and a force plate. One walking cycle of the paretic side was analyzed. [Results] Walking speed, stride length, and cadence were significantly lower in backward walking than in forward walking. Peak hip extension was significantly lower in backward walking and peak hip flexion moment, knee extension moment, and ankle dorsiflexion and plantar flexion moments were lower in backward walking. [Conclusion] Unlike forward walking, backward walking requires conscious hip joint extension. Conscious extension of the hip joint is hard for stroke patients with hemiplegia. Therefore, the range of hip joint movement declined in backward walking, and walking speed and stride length also declined. The peak ankle plantar flexion moment was significantly lower in backward walking than in forward walking, and it was hard to generate propulsion power in backward walking. These difficulties also affected the walking speed. PMID:28265136

  11. Mode-dependent control of human walking and running as revealed by split-belt locomotor adaptation.

    PubMed

    Ogawa, Tetsuya; Kawashima, Noritaka; Obata, Hiroki; Kanosue, Kazuyuki; Nakazawa, Kimitaka

    2015-10-01

    Here, we investigate the association of neural control between walking and running, and in particular, how these two gait modes at different velocities are controlled by the central nervous system. The subjects were fully adapted by acquiring modified motor patterns to either walk or run on a split-belt treadmill driven in split mode (asymmetry in the velocities of two belts at 1.0 and 2.0 m s(-1)). Subsequently, we tested how the adaptation affected walking and running at three different velocities in the tied mode (equal belt velocities). At 0.75 m s(-1), we found a preference to walk, at 1.50 m s(-1), there was a preference to both walk and run, and at a velocity of 2.25 m s(-1) there was a preference to run. Both walking and running on the split belt resulted in the emergence of a significant aftereffect (asymmetrical movement) at all of the velocities tested when walking after adapting to walk and running after adapting to run. However, for contrasting modes (i.e. running after adapting to walk and walking after adapting to run), such aftereffects were far less evident at all velocities; thus showing only limited transfer across gait modes. The results demonstrate a clear mode dependency in the neural control of human walking and running. In addition, only for walking, was there a degree of velocity dependency.

  12. Biomechanical comparison of frontal plane knee joint moment arms during normal and Tai Chi walking.

    PubMed

    Jagodinsky, Adam; Fox, John; Decoux, Brandi; Weimar, Wendi; Liu, Wei

    2015-09-01

    [Purpose] Medial knee osteoarthritis, a degenerative joint disease, affects adults. The external knee adduction moment, a surrogate knee-loading measure, has clinical implications for knee osteoarthritis patients. Tai Chi is a promising intervention for pain alleviation in knee osteoarthritis; however, the characteristics of external knee adduction moment during Tai Chi have not been established. [Subjects and Methods] During normal and Tai Chi walking, a gait analysis was performed to compare the external knee adduction moment moment-arm characteristics and paired t-tests to compare moment-arm magnitudes. [Results] A significant difference was observed in the average lateral direction of moment-arm magnitude during Tai Chi walking (-0.0239 ± 0.011 m) compared to that during normal walking (-0.0057 ± 0.004 m). No significant difference was found between conditions in average medial direction of moment-arm magnitude (normal walking: 0.0143 ± 0.010 m; Tai Chi walking: 0.0098 ± 0.014 m). [Conclusion] Tai Chi walking produced a larger peak lateral moment-arm value than normal walking during the stance phase, whereas Tai Chi walking and normal walking peak medial moment-arm values were similar, suggesting that medial knee joint loading may be avoided during Tai Chi walking.

  13. Mechanical design of walking machines.

    PubMed

    Arikawa, Keisuke; Hirose, Shigeo

    2007-01-15

    The performance of existing actuators, such as electric motors, is very limited, be it power-weight ratio or energy efficiency. In this paper, we discuss the method to design a practical walking machine under this severe constraint with focus on two concepts, the gravitationally decoupled actuation (GDA) and the coupled drive. The GDA decouples the driving system against the gravitational field to suppress generation of negative power and improve energy efficiency. On the other hand, the coupled drive couples the driving system to distribute the output power equally among actuators and maximize the utilization of installed actuator power. First, we depict the GDA and coupled drive in detail. Then, we present actual machines, TITAN-III and VIII, quadruped walking machines designed on the basis of the GDA, and NINJA-I and II, quadruped wall walking machines designed on the basis of the coupled drive. Finally, we discuss walking machines that travel on three-dimensional terrain (3D terrain), which includes the ground, walls and ceiling. Then, we demonstrate with computer simulation that we can selectively leverage GDA and coupled drive by walking posture control.

  14. Feature Learning Based Random Walk for Liver Segmentation

    PubMed Central

    Zheng, Yongchang; Ai, Danni; Zhang, Pan; Gao, Yefei; Xia, Likun; Du, Shunda; Sang, Xinting; Yang, Jian

    2016-01-01

    Liver segmentation is a significant processing technique for computer-assisted diagnosis. This method has attracted considerable attention and achieved effective result. However, liver segmentation using computed tomography (CT) images remains a challenging task because of the low contrast between the liver and adjacent organs. This paper proposes a feature-learning-based random walk method for liver segmentation using CT images. Four texture features were extracted and then classified to determine the classification probability corresponding to the test images. Seed points on the original test image were automatically selected and further used in the random walk (RW) algorithm to achieve comparable results to previous segmentation methods. PMID:27846217

  15. Slow walking model for children with multiple disabilities via an application of humanoid robot

    NASA Astrophysics Data System (ADS)

    Wang, ZeFeng; Peyrodie, Laurent; Cao, Hua; Agnani, Olivier; Watelain, Eric; Wang, HaoPing

    2016-02-01

    Walk training research with children having multiple disabilities is presented. Orthosis aid in walking for children with multiple disabilities such as Cerebral Palsy continues to be a clinical and technological challenge. In order to reduce pain and improve treatment strategies, an intermediate structure - humanoid robot NAO - is proposed as an assay platform to study walking training models, to be transferred to future special exoskeletons for children. A suitable and stable walking model is proposed for walk training. It would be simulated and tested on NAO. This comparative study of zero moment point (ZMP) supports polygons and energy consumption validates the model as more stable than the conventional NAO. Accordingly direction variation of the center of mass and the slopes of linear regression knee/ankle angles, the Slow Walk model faithfully emulates the gait pattern of children.

  16. Exercise testing in severe emphysema: association with quality of life and lung function.

    PubMed

    Brown, Cynthia D; Benditt, Joshua O; Sciurba, Frank C; Lee, Shing M; Criner, Gerard J; Mosenifar, Zab; Shade, David M; Slivka, William A; Wise, Robert A

    2008-04-01

    Six-minute walk testing (6MWT) and cardiopulmonary exercise testing (CPX) are used to evaluate impairment in emphysema. However, the extent of impairment in these tests as well as the correlation of these tests with each other and lung function in advanced emphysema is not well characterized. During screening for the National Emphysema Treatment Trial, maximum ergometer CPX and 6MWT were performed in 1,218 individuals with severe COPD with an average FEV(1) of 26.9 +/- 7.1 % predicted. Predicted values for 6MWT and CPX were calculated from reference equations. Correlation coefficients and multivariable regression models were used to determine the association between lung function, quality of life (QOL) scores, and exercise measures. The two forms of exercise testing were correlated with each other (r = 0.57, p < 0.0001). However, the impairment of performance on CPX was greater than on the 6MWT (27.6 +/- 16.8 vs. 67.9 +/- 18.9 % predicted). Both exercise tests had similar correlation with measures of QOL, but maximum exercise capacity was better correlated with lung function measures than 6-minute walk distance. After adjustment, 6MWD had a slightly greater association with total SGRQ score than maximal exercise (effect size 0.37 +/- 0.04 vs. 0.25 +/- 0.03 %predicted/unit). Despite advanced emphysema, patients are able to maintain 6MWD to a greater degree than maximum exercise capacity. Moreover, the 6MWT may be a better test of functional capacity given its greater association with QOL measures whereas CPX is a better test of physiologic impairment.

  17. Minimal walking distance following exercise treatment in patients with arterial occlusive disease.

    PubMed

    Rosetzsky, A; Struckmann, J; Mathiesen, F R

    1985-01-01

    79 patients with intermittent claudication were tested with peripheral blood pressure measurement and determination of minimal walking distance before and after a 3 months' period with scheduled walking exercises under supervision. No change in peripheral blood pressure was observed following the treatment whereas the minimum walking distance was increased with statistical significance. The gain was most pronounced in patients with an initial combination of high peripheral pressures and short walking distances. A graphic presentation allows for the estimation of the expected gain in individual patients with claudication.

  18. Szegedy's quantum walk with queries

    NASA Astrophysics Data System (ADS)

    Santos, Raqueline A. M.

    2016-11-01

    When searching for a marked vertex in a graph, Szegedy's usual search operator is defined by using the transition probability matrix of the random walk with absorbing barriers at the marked vertices. Instead of using this operator, we analyze searching with Szegedy's quantum walk by using reflections around the marked vertices, that is, the standard form of quantum query. We show we can boost the probability to 1 of finding a marked vertex in the complete graph. Numerical simulations suggest that the success probability can be improved for other graphs, like the two-dimensional grid. We also prove that, for a certain class of graphs, we can express Szegedy's search operator, obtained from the absorbing walk, using the standard query model.

  19. Sedentary behavior is associated with disability status and walking performance, but not cognitive function, in multiple sclerosis.

    PubMed

    Hubbard, Elizabeth A; Motl, Robert W

    2015-02-01

    Eighty-two persons with multiple sclerosis wore an accelerometer as a measure of sedentary time (min/day) and completed measures of disability status (self-reported Expanded Disability Status Scale), walking performance (timed 25-foot walk and 6-min walk), and cognitive function (symbol digit modalities test). Accelerometry-measured sedentary time was significantly correlated with disability status scores (r = 0.31, p < 0.01), 6-min walk distance (r = -0.40, p < 0.01), and timed 25-foot walk performance (r = 0.35, p < 0.01), but not cognitive function performance (r = -0.12, p = 0.29).

  20. Attuning one's steps to visual targets reduces comfortable walking speed in both young and older adults.

    PubMed

    Peper, C Lieke E; de Dreu, Miek J; Roerdink, Melvyn

    2015-03-01

    Comfortable walking speed (CWS) is indicative of clinically relevant factors in the elderly, such as fall risk and mortality. Standard CWS tests involve walking on a straight, unobstructed surface, while in reality surfaces are uneven and cluttered and so walkers rely on visually guided adaptations to avoid trips or slips. Hence, the predictive value of CWS may be expected to increase when assessed for walking in more realistic (visually guided) conditions. We examined CWS in young (n=18) and older (n=18) adults for both overground and treadmill walking. Overground CWS was assessed using the 10-meter walk test with and without visual stepping targets. For treadmill walking, four conditions were examined: (i) uncued walking, and (ii-iv) cued walking with visual stepping targets where the inter-stepping target distance varied by 0%, 20%, or 40%. Pre-experimental measures were taken so that the average inter-stepping target distance could be adjusted for each belt speed based on each participant's self-selected gait characteristics. Results showed that CWS was significantly slower when stepping targets were present in both overground (p<.001) and treadmill walking (p<.001). Thus, attuning steps to visual targets significantly affected CWS, even when the patterning of these targets matched the participant's own gait pattern (viz. 0%-treadmill-walking condition). Results from the treadmill-walking task showed that the amount of variation in inter-stepping target distance did not differentially affect CWS. Our results suggest that it may be worthwhile in clinical assessments to not only determine walking speed using standard conditions but also in situations that require visually guided stepping.

  1. Mobile gaze tracking system for outdoor walking behavioral studies

    PubMed Central

    Tomasi, Matteo; Pundlik, Shrinivas; Bowers, Alex R.; Peli, Eli; Luo, Gang

    2016-01-01

    Most gaze tracking techniques estimate gaze points on screens, on scene images, or in confined spaces. Tracking of gaze in open-world coordinates, especially in walking situations, has rarely been addressed. We use a head-mounted eye tracker combined with two inertial measurement units (IMU) to track gaze orientation relative to the heading direction in outdoor walking. Head movements relative to the body are measured by the difference in output between the IMUs on the head and body trunk. The use of the IMU pair reduces the impact of environmental interference on each sensor. The system was tested in busy urban areas and allowed drift compensation for long (up to 18 min) gaze recording. Comparison with ground truth revealed an average error of 3.3° while walking straight segments. The range of gaze scanning in walking is frequently larger than the estimation error by about one order of magnitude. Our proposed method was also tested with real cases of natural walking and it was found to be suitable for the evaluation of gaze behaviors in outdoor environments. PMID:26894511

  2. Walking droplets in confined domains

    NASA Astrophysics Data System (ADS)

    Sáenz, Pedro; Bush, John

    2016-11-01

    A millimetric liquid drop can walk spontaneously along the surface of a vibrating fluid bath, propelled by a resonant interaction with its own wave field. These walking droplets exhibit features previously thought to be exclusive to the microscopic quantum realm. We here explore experimentally the dynamics and statistics of this macroscopic wave-particle system in confined domains, or 'corrals'. Particular attention is given to characterizing the influence of the corral geometry on the emergent probability distributions. The relation to analogous quantum systems (specifically, quantum corrals, the quantum mirage and scarring in Bose-Einstein condensates) is discussed. NSF support via CMMI-1333242.

  3. The reliability of local dynamic stability in walking while texting and performing an arithmetical problem.

    PubMed

    Hamacher, Dennis; Hamacher, Daniel; Törpel, Alexander; Krowicki, Martin; Herold, Fabian; Schega, Lutz

    2016-02-01

    In the recent years, local dynamic stability of walking was frequently used to quantify motor control. Particularly, dual-task paradigms are used to assess a shift in gait control strategy to test walking in real life situations. Texting short messages while walking is a common motor-cognitive dual task of daily living. To able to monitor possible intervention effects on motor-cognitive dual-task performance, the test-retest reliability of the measure has to be evaluated. Since the reliability of the effects of cognitive tasks including texting while walking on local dynamic gait stability has not been assessed yet, this will be evaluated in the current study. Eleven young individuals were included. Gait data was registered twice (test-retest interval: seven days) using an inertial sensor fixed on the subjects' trunks in three conditions: normal walking, walking while texting a message and walking while reciting serials of 7. Short-term finite maximum Lyapunov Exponents were quantified to assess local dynamic stability. The test-retest reliability was calculated using intra-class correlation coefficients and Bland and Altman Plots (bias and limits of agreement). ICC values of the current study show that in normal walking and walking while texting, outcomes are comparable and indicate mostly good to excellent reliability. The reliability values were almost always the lowest in walking while reciting serials of 7. Local dynamic stability derived from kinematic data of walking while cell phone texting can be reliably collected and, in turn, be used as an outcome measure in clinical trials with repeated measures design.

  4. After Talking the Talk, Now Walk the Walk

    ERIC Educational Resources Information Center

    Vukovic, Paul

    2011-01-01

    In this article, the author describes what his students are doing following the ATM Easter conference in Telford, where he was inspired by a workshop entitled "Vitamin D Maths," conducted by Jocelyn D'Arcy. He describes an activity that allows his Year 11 students to walk through angles drawn on the floors. This topic will now literally…

  5. The Role of Crawling and Walking Experience in Infant Spatial Memory

    ERIC Educational Resources Information Center

    Clearfield, M.W.

    2004-01-01

    This research explored infants' use of place learning and cue learning in a locomotor task across the transition from crawling to walking. Novice and expert crawling and walking infants were observed in a novel locomotor task -- finding a hidden goal location in a large space. In Experiment 1, infants were tested with distal landmarks. Infants…

  6. Brisk Walk May Help Sidestep Heart Disease

    MedlinePlus

    ... fullstory_162978.html Brisk Walk May Help Sidestep Heart Disease In just 10 weeks, cholesterol, blood pressure and ... at moderate intensity may lower the risk of heart disease, a small study suggests. "We know walking is ...

  7. Crutches and children - standing and walking

    MedlinePlus

    ... patientinstructions/000641.htm Crutches and children - standing and walking To use the sharing features on this page, ... leg. Keep the crutches slightly forward and apart. Walking with Crutches (No Weight Bearing on Hurt Foot ...

  8. Dissipative quantum computing with open quantum walks

    SciTech Connect

    Sinayskiy, Ilya; Petruccione, Francesco

    2014-12-04

    An open quantum walk approach to the implementation of a dissipative quantum computing scheme is presented. The formalism is demonstrated for the example of an open quantum walk implementation of a 3 qubit quantum circuit consisting of 10 gates.

  9. On Convergent Probability of a Random Walk

    ERIC Educational Resources Information Center

    Lee, Y.-F.; Ching, W.-K.

    2006-01-01

    This note introduces an interesting random walk on a straight path with cards of random numbers. The method of recurrent relations is used to obtain the convergent probability of the random walk with different initial positions.

  10. Dalfampridine Effects Beyond Walking Speed in Multiple Sclerosis

    PubMed Central

    Fjeldstad, Cecilie; Suárez, Gustavo; Klingler, Michael; Henney, Herbert R.; Rabinowicz, Adrian L.

    2015-01-01

    Background: Dalfampridine extended release (ER) improves walking in people with multiple sclerosis (MS), as demonstrated by walking speed improvement. This exploratory study evaluated treatment effects of dalfampridine-ER on gait, balance, and walking through treatment withdrawal and reinitiation. Methods: Dalfampridine-ER responders, based on Timed 25-Foot Walk (T25FW) assessment before study entry, were included in this open-label, three-period, single-center study. Period 1: on-drug evaluations performed at screening and 1 week after screening. Period 2: dalfampridine-ER withdrawal and off-drug evaluations (days 5 and 11). Period 3: dalfampridine-ER reinitiation/final on-drug evaluation (day 15). Primary outcome variables: NeuroCom composite scores for gait and balance; balance was evaluated if gait changes were significant. Secondary variables: individual NeuroCom scores, walking speed (T25FW) and distance (2-Minute Walk Test [2MWT]), and balance (Berg Balance Scale [BBS]). Results: All 20 patients completed the study: mean age, 53.1 years; mean MS duration, 11.3 years; mean time taking dalfampridine-ER, 315.3 days. NeuroCom gait composite scores worsened during period 2 relative to period 1 and improved during period 3; the mean ± SD difference in gait composite scores on drug was 4.03 ± 1.51 points (P = .015). Balance composite scores did not change significantly. Improvements were observed for off-drug versus on-drug for T25FW (0.36 ft/sec, P < .001), 2MWT (25.4 ft, P = .006), and BBS (1.7 points, P = .003). Safety profile was consistent with previous studies. Conclusions: Significant improvements in gait, walking speed, distance, and balance were demonstrated by dalfampridine-ER reinitiation after a 10-day withdrawal period. PMID:26664333

  11. Metabolic Differences Between Shod and Barefoot Walking in Children.

    PubMed

    Shultz, S P; Houltham, S D; Kung, S M; Hume, P; Fink, P W

    2016-05-01

    Footwear affects the biomechanics of children's gait; however, there has been less research addressing the energetics of walking with and without shoes. This study investigated the effects of barefoot and shod walking on metabolic parameters in children. 25 children (9.7±1.4 years) walked at a self-selected pace for 5 min on an instrumented treadmill under 2 footwear conditions (barefoot, running shoe). Vertical oscillations of centre of mass were calculated from ground reaction forces. Expired gases were collected in the last minute of each trial. Paired t-tests revealed significantly higher oxygen consumption (17.6±2.5 ml.kg(-1).min(-1) vs. 16.3±3.1 ml.kg(-1).min(-1)), energy expenditure (3.25±0.86 kcal.min(-1) vs. 2.97±0.68 kcal.min(-1)), and economy (298.2±47.5 ml.kg(-1).km(-1) vs. 275.9±56.9 ml.kg(-1).km(-1)) during the shod condition. There was no difference in substrate utilization between conditions. The barefoot condition elicited a smaller centre of mass vertical displacement (1.24±0.14 cm vs. 1.34±0.17 cm). At a natural walking speed, barefoot walking is more economical than shod walking at the same velocity in children. The higher energy cost of shod walking should be considered when evaluating the use of footwear by children.

  12. Biomechanics and energetics of walking on uneven terrain

    PubMed Central

    Voloshina, Alexandra S.; Kuo, Arthur D.; Daley, Monica A.; Ferris, Daniel P.

    2013-01-01

    SUMMARY Walking on uneven terrain is more energetically costly than walking on smooth ground, but the biomechanical factors that contribute to this increase are unknown. To identify possible factors, we constructed an uneven terrain treadmill that allowed us to record biomechanical, electromyographic and metabolic energetics data from human subjects. We hypothesized that walking on uneven terrain would increase step width and length variability, joint mechanical work and muscle co-activation compared with walking on smooth terrain. We tested healthy subjects (N=11) walking at 1.0 m s−1, and found that, when walking on uneven terrain with up to 2.5 cm variation, subjects decreased their step length by 4% and did not significantly change their step width, while both step length and width variability increased significantly (22 and 36%, respectively; P<0.05). Uneven terrain walking caused a 28 and 62% increase in positive knee and hip work, respectively, and a 26% greater magnitude of negative knee work (0.0106, 0.1078 and 0.0425 J kg−1, respectively; P<0.05). Mean muscle activity increased in seven muscles in the lower leg and thigh (P<0.05). These changes caused overall net metabolic energy expenditure to increase by 0.73 W kg−1 (28%; P<0.0001). Much of that increase could be explained by the increased mechanical work observed at the knee and hip. Greater muscle co-activation could also contribute to increased energetic cost but to unknown degree. The findings provide insight into how lower limb muscles are used differently for natural terrain compared with laboratory conditions. PMID:23913951

  13. Quadratus femoris: An EMG investigation during walking and running.

    PubMed

    Semciw, Adam I; Freeman, Michael; Kunstler, Breanne E; Mendis, M Dilani; Pizzari, Tania

    2015-09-18

    Dysfunction of hip stabilizing muscles such as quadratus femoris (QF) is identified as a potential source of lower extremity injury during functional tasks like running. Despite these assumptions, there are currently no electromyography (EMG) data that establish the burst activity profile of QF during any functional task like walking or running. The objectives of this study were to characterize and compare the EMG activity profile of QF while walking and running (primary aim) and describe the direction specific action of QF (secondary aim). A bipolar fine-wire intramuscular electrode was inserted via ultrasound guidance into the QF of 10 healthy participants (4 females). Ensemble curves were generated from four walking and running trials, and normalized to maximum voluntary isometric contractions (MVICs). Paired t-tests compared the temporal and amplitude EMG variables. The relative activity of QF in the MVICs was calculated. The QF displayed moderate to high amplitude activity in the stance phase of walking and very high activity during stance in running. During swing, there was minimal QF activity recorded during walking and high amplitudes were present while running (run vs walk effect size=4.23, P<0.001). For the MVICs, external rotation and clam produced the greatest QF activity, with the hip in the anatomical position. This study provides an understanding of the activity demands placed on QF while walking and running. The high activity in late swing during running may signify a synergistic role with other posterior thigh muscles to control deceleration of the limb in preparation for stance.

  14. Biomechanics and energetics of walking on uneven terrain.

    PubMed

    Voloshina, Alexandra S; Kuo, Arthur D; Daley, Monica A; Ferris, Daniel P

    2013-11-01

    Walking on uneven terrain is more energetically costly than walking on smooth ground, but the biomechanical factors that contribute to this increase are unknown. To identify possible factors, we constructed an uneven terrain treadmill that allowed us to record biomechanical, electromyographic and metabolic energetics data from human subjects. We hypothesized that walking on uneven terrain would increase step width and length variability, joint mechanical work and muscle co-activation compared with walking on smooth terrain. We tested healthy subjects (N=11) walking at 1.0 m s(-1), and found that, when walking on uneven terrain with up to 2.5 cm variation, subjects decreased their step length by 4% and did not significantly change their step width, while both step length and width variability increased significantly (22 and 36%, respectively; P<0.05). Uneven terrain walking caused a 28 and 62% increase in positive knee and hip work, respectively, and a 26% greater magnitude of negative knee work (0.0106, 0.1078 and 0.0425 J kg(-1), respectively; P<0.05). Mean muscle activity increased in seven muscles in the lower leg and thigh (P<0.05). These changes caused overall net metabolic energy expenditure to increase by 0.73 W kg(-1) (28%; P<0.0001). Much of that increase could be explained by the increased mechanical work observed at the knee and hip. Greater muscle co-activation could also contribute to increased energetic cost but to unknown degree. The findings provide insight into how lower limb muscles are used differently for natural terrain compared with laboratory conditions.

  15. A simple and rapid test of physical performance in chronic obstructive pulmonary disease

    PubMed Central

    Albarrati, Ali Mufraih; Gale, Nichola S; Enright, Stephanie; Munnery, Margaret M; Cockcroft, John R; Shale, Dennis J

    2016-01-01

    Impaired physical performance is common in chronic obstructive pulmonary disease (COPD), but its assessment can be difficult in routine clinical practice. We compared the timed up and go (TUG) test and other easily applied assessments of physical performance with the 6-minute walk distance (6MWD). In a longitudinal study of comorbidities in COPD, submaximal physical performance was determined in 520 patients and 150 controls using the TUG test and 6MWD. Spirometry, body composition, handgrip strength, the COPD assessment test, St George’s Respiratory Questionnaire (SGRQ), and the modified Medical Research Council dyspnoea scale were also determined. Patients and controls were similar in age, body mass index, and sex proportions. The TUG in the patients was greater than that in the control group, P=0.001, and was inversely related to 6MWD (r=−0.71, P<0.001) and forced expiratory volume in one second predicted (r=−0.19, P<0.01) and was directly related to the SGRQ activity (r=0.39, P<0.001), SGRQ total (r=0.37, P<0.001), and total COPD assessment test scores (r=0.37, P<0.001). The TUG identified the difference in physical performance between patients and controls. The TUG test and validated questionnaires provide a measure of physical performance, which is rapid and could be used in clinical practice. PMID:27536090

  16. A Walk to the Well.

    ERIC Educational Resources Information Center

    Weir, Phil

    1994-01-01

    During a walk, an outdoor education teacher reflects on the status of outdoor education in Ottawa (Canada) and importance of maintaining a close relationship with nature. He looks for signs of an old log home site, observes a hawk's flight, discovers remains of a plastic bag in an owl pellet, and realizes that everyone is working on survival. (LP)

  17. Walking Tips for Older Adults

    MedlinePlus

    ... the most ppular form of exercise among older adults and it's a great choice. What can walking do for you? strengthen muscles help prevent weight gain lower risks of heart disease, stroke, diabetes, and osteoporosis improve balance lower the likelihood of falling If ...

  18. Successful Statewide Walking Program Websites

    ERIC Educational Resources Information Center

    Teran, Bianca Maria; Hongu, Nobuko

    2012-01-01

    Statewide Extension walking programs are making an effort to increase physical activity levels in America. An investigation of all 20 of these programs revealed that 14 use websites as marketing and educational tools, which could prove useful as the popularity of Internet communities continues to grow. Website usability information and an analysis…

  19. Behavior Management by Walking Around

    ERIC Educational Resources Information Center

    Boardman, Randolph M.

    2004-01-01

    An emerging concept from the field of business is to manage organizations by wandering around and engaging staff and consumers in informal interactions. The author extends these ideas to settings serving children and youth. In the best seller, In Search of Excellence, Peters and Waterman (1982) introduced Management by Walking Around (MBWA) as an…

  20. Walk around the Block Curriculum.

    ERIC Educational Resources Information Center

    Center for Understanding the Built Environment, Prairie Village, KS.

    This curriculum packet contains two teacher-developed lesson plans for upper elementary students focusing on the built environment. The first lesson plan, "The Built Environment--An Integrating Theme" (Liesa Schroeder), offers suggestions for developing a walking tour around the school neighborhood, a historic area, or a city square. It…

  1. Walking to Save a County.

    ERIC Educational Resources Information Center

    Slotnick, Karen

    1981-01-01

    Describes the 10-year history and accomplishments of the Walk to Save the County which has preserved more than 400 acres of Onondaga County, New York. Outlines organizational structure, promotional strategies, awards, and educational opportunities involved in this annual fund-raising hike by third- through eighth-grade students. (NEC)

  2. KidsWalk-to-School: A Guide To Promote Walking to School.

    ERIC Educational Resources Information Center

    Center for Chronic Disease Prevention and Health Promotion (DHHS/CDC), Atlanta, GA.

    This guide encourages people to create safe walking and biking routes to school, promoting four issues: physically active travel, safe and walkable routes to school, crime prevention, and health environments. The chapters include: "KidsWalk-to-School: A Guide to Promote Walking to School" (Is there a solution? Why is walking to school important?…

  3. Walking pattern classification and walking distance estimation algorithms using gait phase information.

    PubMed

    Wang, Jeen-Shing; Lin, Che-Wei; Yang, Ya-Ting C; Ho, Yu-Jen

    2012-10-01

    This paper presents a walking pattern classification and a walking distance estimation algorithm using gait phase information. A gait phase information retrieval algorithm was developed to analyze the duration of the phases in a gait cycle (i.e., stance, push-off, swing, and heel-strike phases). Based on the gait phase information, a decision tree based on the relations between gait phases was constructed for classifying three different walking patterns (level walking, walking upstairs, and walking downstairs). Gait phase information was also used for developing a walking distance estimation algorithm. The walking distance estimation algorithm consists of the processes of step count and step length estimation. The proposed walking pattern classification and walking distance estimation algorithm have been validated by a series of experiments. The accuracy of the proposed walking pattern classification was 98.87%, 95.45%, and 95.00% for level walking, walking upstairs, and walking downstairs, respectively. The accuracy of the proposed walking distance estimation algorithm was 96.42% over a walking distance.

  4. The 1991-1992 walking robot design

    NASA Technical Reports Server (NTRS)

    Azarm, Shapour; Dayawansa, Wijesurija; Tsai, Lung-Wen; Peritt, Jon

    1992-01-01

    The University of Maryland Walking Machine team designed and constructed a robot. This robot was completed in two phases with supervision and suggestions from three professors and one graduate teaching assistant. Bob was designed during the Fall Semester 1991, then machined, assembled, and debugged in the Spring Semester 1992. The project required a total of 4,300 student hours and cost under $8,000. Mechanically, Bob was an exercise in optimization. The robot was designed to test several diverse aspects of robotic potential, including speed, agility, and stability, with simplicity and reliability holding equal importance. For speed and smooth walking motion, the footpath contained a long horizontal component; a vertical aspect was included to allow clearance of obstacles. These challenges were met with a leg design that utilized a unique multi-link mechanism which traveled a modified tear-drop footpath. The electrical requirements included motor, encoder, and voice control circuitry selection, manual controller manufacture, and creation of sensors for guidance. Further, there was also a need for selection of the computer, completion of a preliminary program, and testing of the robot.

  5. A comparison of variability in spatiotemporal gait parameters between treadmill and overground walking conditions.

    PubMed

    Hollman, John H; Watkins, Molly K; Imhoff, Angela C; Braun, Carly E; Akervik, Kristen A; Ness, Debra K

    2016-01-01

    Motorized treadmills are commonly used in biomechanical and clinical studies of human walking. Whether treadmill walking induces identical motor responses to overground walking, however, is equivocal. The purpose of this study was to examine differences in the spatiotemporal gait parameters of the lower extremities and trunk during treadmill and overground walking using comparison of mean and variability values. Twenty healthy participants (age 23.8±1.2 years) walked for 6min on a treadmill and overground while wearing APDM 6 Opal inertial monitors. Stride length, stride time, stride velocity, cadence, stance phase percentage, and peak sagittal and frontal plane trunk velocities were measured. Mean values were calculated for each parameter as well as estimates of short- (SD1) and long-term variability (SD2) using Poincaré analyses. The mean, SD1, and SD2 values were compared between overground and treadmill walking conditions with paired t-tests (α=0.05) and with effect size estimates using Cohen's d statistic. Mean values for each of the gait parameters were statistically equivalent between treadmill and overground walking (p>0.05). The SD1 and SD2 values representing short- and long-term variability were considerably reduced (p<0.05) on the treadmill as compared to overground walking. This demonstrates the importance of consideration of gait variability when using treadmills for research or clinical purposes. Treadmill training may induce invariant gait patterns, posing difficulty in translating locomotor skills gained on a treadmill to overground walking conditions.

  6. Developmental Continuity? Crawling, Cruising, and Walking

    ERIC Educational Resources Information Center

    Adolph, Karen E.; Berger, Sarah E.; Leo, Andrew J.

    2011-01-01

    This research examined developmental continuity between "cruising" (moving sideways holding onto furniture for support) and walking. Because cruising and walking involve locomotion in an upright posture, researchers have assumed that cruising is functionally related to walking. Study 1 showed that most infants crawl and cruise concurrently prior…

  7. Generalized Open Quantum Walks on Apollonian Networks

    PubMed Central

    Pawela, Łukasz; Gawron, Piotr; Miszczak, Jarosław Adam; Sadowski, Przemysław

    2015-01-01

    We introduce the model of generalized open quantum walks on networks using the Transition Operation Matrices formalism. We focus our analysis on the mean first passage time and the average return time in Apollonian networks. These results differ significantly from a classical walk on these networks. We show a comparison of the classical and quantum behaviour of walks on these networks. PMID:26177452

  8. Cognitive and Typing Outcomes Measured Simultaneously with Slow Treadmill Walking or Sitting: Implications for Treadmill Desks

    PubMed Central

    Larson, Michael J.; LeCheminant, James D.; Hill, Kyle; Carbine, Kaylie; Masterson, Travis; Christenson, Ed

    2015-01-01

    Purpose This study compared cognitive (attention, learning, and memory) and typing outcomes during slow treadmill walking or sitting. Seventy-five healthy individuals were randomly assigned to a treadmill walking group (n=37; 23 female) or sitting group (n=38; 17 female). Methods The treadmill walking group completed a series of tests while walking at 1.5 mph. The sitting group performed the same tests while sitting at a standard desk. Tests performed by both groups included: the Rey Auditory Verbal Learning Test and a modified version of the Paced Auditory Serial Attention Test. In addition, typing performance was evaluated. Results Participants in the treadmill walking group performed worse on the Rey Auditory Verbal Learning Test for total learning than the sitting group; the main effect was significant (F(1,73)=4.75, p=0.03, ηp2=0.06); however, short- and long-delay recall performance did not differ between groups (p>0.05). For the Paced Auditory Serial Attention Test, total number of correct responses was lower in the treadmill walking group relative to the sitting group; the main effect was significant (F(1,73)=4.97, p=0.03, ηp2=0.06). The performance of both groups followed the same learning slope (Group x Trial interactions were not significant) for the Rey Auditory Verbal Learning Test and Paced Auditory Serial Attention Test. Individuals in the treadmill walking group performed significantly worse for all measures of typing (p<0.05). Conclusion Walking on a treadmill desk may result in a modest difference in total learning and typing outcomes relative to sitting, but those declines may not outweigh the benefit of the physical activity gains from walking on a treadmill. PMID:25874910

  9. The Effects of Vibration on the Gait Pattern and Vibration Perception Threshold of Children With Idiopathic Toe Walking.

    PubMed

    Fanchiang, Hsinchen Daniel; Geil, Mark; Wu, Jianhua; Chen, Yu-Ping; Wang, Yong Tai

    2015-07-01

    The effectiveness of idiopathic toe walking treatments is not conclusive. The study investigated the use of vibration as a therapeutic/treatment method for children with idiopathic toe walking. Fifteen children with idiopathic toe walking and 15 typically developing children, aged 4 to 10 years, completed the study. The study included a barefoot gait examination and a vibration perception threshold test before and after standing on a whole body vibration machine for 60 seconds. Temporal-spatial parameters were recorded along with HR32, a calculation designed to distinguish on aspects of the toe-walking pattern. No significant gait pattern differences were found between children with idiopathic toe walking and typically developing children after one bout of vibration intervention. HR32 was found to be a means to identify the toe-walking pattern (P < .001). Hypersensitivity to vibration of children with idiopathic toe walking was not found in the current study (P = .921).

  10. The effects of a progressive resistance training program on walking ability in patients after stroke: a pilot study

    PubMed Central

    Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Park, Jaehong; Kim, Junghwan

    2015-01-01

    [Purpose] The purpose of this study was to evaluate the effects of a progressive resistance training (PRT) program on the walking ability of chronic stroke patients with hemiparesis following chronic stroke. [Subjects and Methods] The participants of this study were fifteen hemiplegic patients. The main outcomes measured for this study were the peak torque of the knee extensor; the gait ability as measured by electric gait analysis of walking speed, walking cycle, affected side stance phase, affected side stride length, symmetry index of stance phase, and symmetry index of stride length; and 10-m walking speed; and the Berg balance scale test. [Results] Walking speed and affected side stride length significantly increased after the PRT program, and 10-m walking time significantly decreased after RPT in stroke patients. [Conclusion] These results suggest that the progressive resistance training program may, in part, improve the stride of the affected side leg of stroke patients after stroke and also positively impact walking speed. PMID:26504305

  11. Running, walking, and hyperventilation causing asthma in children.

    PubMed Central

    Kilham, H; Tooley, M; Silverman, M

    1979-01-01

    To examine further the relation between type of exercise, workload, ventilation, and exercise-induced asthma, we compared treadmill walking with treadmill running and treadmill running with isocapnic hyperventilation in separate studies in children and adolescents. Inspired air conditions were identical during each pair of tests. Walking and running with similar minute ventilation and oxygen consumption were followed by similar falls in peak expiratory flow rate as were running and hyperventilation with similar minute ventilation and end-tidal carbon dioxide tension. This study supports the concept that hyperventilation is a central mechanism in exercise-induced asthma. PMID:515978

  12. Quadriceps oxygenation changes during walking and running on a treadmill

    NASA Astrophysics Data System (ADS)

    Quaresima, Valentina; Pizzi, Assunta; De Blasi, Roberto A.; Ferrari, Adriano; de Angelis, Marco; Ferrari, Marco

    1995-04-01

    Vastus lateralis muscle oxygenation was investigated on volunteers as well as muscular dystrophy patients during a walking test, and on volunteers during a free running by a continuous wave near infrared instrument. The data were analyzed using an oxygenation index independent on pathlength changes. Walking did not significantly affect the oxygenation of volunteers and patients. A relative deoxygenation was found only during free running indicating an unbalance between oxygen supply and tissue oxygen extraction. Preliminary measurements of exercising muscle oxygen saturation were performed by a 110 MHz frequency-domain, multisource instrument.

  13. Walking robot: A design project for undergraduate students

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The objective of the University of Maryland walking robot project was to design, analyze, assemble, and test an intelligent, mobile, and terrain-adaptive system. The robot incorporates existing technologies in novel ways. The legs emulate the walking path of a human by an innovative modification of a crank-and-rocker mechanism. The body consists of two tripod frames connected by a turning mechanism. The two sets of three legs are mounted so as to allow the robot to walk with stability in its own footsteps. The computer uses a modular hardware design and distributed processing. Dual-port RAM is used to allow communication between a supervisory personal computer and seven microcontrollers. The microcontrollers provide low-level control for the motors and relieve the processing burden on the PC.

  14. Direct comparison of the BD phoenix system with the MicroScan WalkAway system for identification and antimicrobial susceptibility testing of Enterobacteriaceae and nonfermentative gram-negative organisms.

    PubMed

    Snyder, J W; Munier, G K; Johnson, C L

    2008-07-01

    The Phoenix automated microbiology system (BD Diagnostics, Sparks, MD) is designed for the rapid identification (ID) and antimicrobial susceptibility testing (AST) of clinically significant human bacterial pathogens. We evaluated the performance of the Phoenix instrument in comparison with that of the MicroScan WalkAway system (Dade Behring, West Sacramento, CA) in the ID and AST of gram-negative clinical strains and challenge isolates of Enterobacteriaceae (n = 150) and nonfermentative gram-negative bacilli (NFGNB; 45 clinical isolates and 8 challenge isolates). ID discrepancies were resolved with the API 20E and API 20NE conventional biochemical ID systems (bioMerieux, Durham, NC). The standard disk diffusion method was used to resolve discordant AST results. The overall percentages of agreement between the Phoenix ID results and the MicroScan results at the genus and species levels for clinical isolates of Enterobacteriaceae were 98.7 and 97.7%, respectively; following resolution with conventional biochemical testing, the accuracy of the Phoenix system was determined to be 100%. For NFGNB, the levels of agreement were 100 and 97.7%, respectively. Both systems incorrectly identified the majority of the uncommon nonfermentative nonpseudomonal challenge isolates recovered from cystic fibrosis patients; these isolates are not included in the databases of the respective systems. For AST of Enterobacteriaceae, the rate of complete agreement between the Phoenix results and the MicroScan results was 97%; the rates of very major, major, and minor errors were 0.3, 0.2, and 2.7%, respectively. For NFGNB, the rate of complete agreement between the Phoenix results and the MicroScan results was 89.1%; the rates of very major, major, and minor errors were 0, 0.5, and 7.7%, respectively. Following the confirmatory testing of nine clinical isolates initially screened by the MicroScan system as possible extended-spectrum-beta-lactamase (ESBL)-producing organisms (seven Klebsiella

  15. Walking stability during cell phone use in healthy adults.

    PubMed

    Kao, Pei-Chun; Higginson, Christopher I; Seymour, Kelly; Kamerdze, Morgan; Higginson, Jill S

    2015-05-01

    The number of falls and/or accidental injuries associated with cellular phone use during walking is growing rapidly. Understanding the effects of concurrent cell phone use on human gait may help develop safety guidelines for pedestrians. It was shown previously that older adults had more pronounced dual-task interferences than younger adults when concurrent cognitive task required visual information processing. Thus, cell phone use might have greater impact on walking stability in older than in younger adults. This study examined gait stability and variability during a cell phone dialing task (phone) and two classic cognitive tasks, the Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT). Nine older and seven younger healthy adults walked on a treadmill at four different conditions: walking only, PASAT, phone, and SDMT. We computed short-term local divergence exponent (LDE) of the trunk motion (local stability), dynamic margins of stability (MOS), step spatiotemporal measures, and kinematic variability. Older and younger adults had similar values of short-term LDE during all conditions, indicating that local stability was not affected by the dual-task. Compared to walking only, older and younger adults walked with significantly greater average mediolateral MOS during phone and SDMT conditions but significantly less ankle angle variability during all dual-tasks and less knee angle variability during PASAT. The current findings demonstrate that healthy adults may try to control foot placement and joint kinematics during cell phone use or another cognitive task with a visual component to ensure sufficient dynamic margins of stability and maintain local stability.

  16. Walking Stability during Cell Phone Use in Healthy Adults

    PubMed Central

    Kao, Pei-Chun; Higginson, Christopher I.; Seymour, Kelly; Kamerdze, Morgan; Higginson, Jill S.

    2015-01-01

    The number of falls and/or accidental injuries associated with cellular phone use during walking is growing rapidly. Understanding the effects of concurrent cell phone use on human gait may help develop safety guidelines for pedestrians. It was shown previously that older adults had more pronounced dual-task interferences than younger adults when concurrent cognitive task required visual information processing. Thus, cell phone use might have greater impact on walking stability in older than in younger adults. This study examined gait stability and variability during a cell phone dialing task (phone) and two classic cognitive tasks, the Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT). Nine older and seven younger healthy adults walked on a treadmill at four different conditions: walking only, PASAT, phone, and SDMT. We computed short-term local divergence exponent (LDE) of the trunk motion (local stability), dynamic margins of stability (MOS), step spatiotemporal measures, and kinematic variability. Older and younger adults had similar values of short-term LDE during all conditions, indicating that local stability was not affected by the dual-task. Compared to walking only, older and younger adults walked with significantly greater average mediolateral MOS during phone and SDMT conditions but significantly less ankle angle variability during all dual-tasks and less knee angle variability during PASAT. The current findings demonstrate that healthy adults may try to control foot placement and joint kinematics during cell phone use or another cognitive task with a visual component to ensure sufficient dynamic margins of stability and maintain local stability. PMID:25890490

  17. Directed random walk with random restarts: The Sisyphus random walk

    NASA Astrophysics Data System (ADS)

    Montero, Miquel; Villarroel, Javier

    2016-09-01

    In this paper we consider a particular version of the random walk with restarts: random reset events which suddenly bring the system to the starting value. We analyze its relevant statistical properties, like the transition probability, and show how an equilibrium state appears. Formulas for the first-passage time, high-water marks, and other extreme statistics are also derived; we consider counting problems naturally associated with the system. Finally we indicate feasible generalizations useful for interpreting different physical effects.

  18. Directed random walk with random restarts: The Sisyphus random walk.

    PubMed

    Montero, Miquel; Villarroel, Javier

    2016-09-01

    In this paper we consider a particular version of the random walk with restarts: random reset events which suddenly bring the system to the starting value. We analyze its relevant statistical properties, like the transition probability, and show how an equilibrium state appears. Formulas for the first-passage time, high-water marks, and other extreme statistics are also derived; we consider counting problems naturally associated with the system. Finally we indicate feasible generalizations useful for interpreting different physical effects.

  19. Walking to a multisensory beat.

    PubMed

    Roy, Charlotte; Lagarde, Julien; Dotov, Dobromir; Dalla Bella, Simone

    2017-04-01

    Living in a complex and multisensory environment demands constant interaction between perception and action. In everyday life it is common to combine efficiently simultaneous signals coming from different modalities. There is evidence of a multisensory benefit in a variety of laboratory tasks (temporal judgement, reaction time tasks). It is less clear if this effect extends to ecological tasks, such as walking. Furthermore, benefits of multimodal stimulation are linked to temporal properties such as the temporal window of integration and temporal recalibration. These properties have been examined in tasks involving single, non-repeating stimulus presentations. Here we investigate the same temporal properties in the context of a rhythmic task, namely audio-tactile stimulation during walking. The effect of audio-tactile rhythmic cues on gait variability and the ability to synchronize to the cues was studied in young adults. Participants walked with rhythmic cues presented at different stimulus-onset asynchronies. We observed a multisensory benefit by comparing audio-tactile to unimodal stimulation. Moreover, both the temporal window of integration and temporal recalibration mediated the response to multimodal stimulation. In sum, rhythmic behaviours obey the same principles as temporal discrimination and detection behaviours and thus can also benefit from multimodal stimulation.

  20. The Effect of Muscle Facilitation Using Kinesio Taping on Walking and Balance of Stroke Patients

    PubMed Central

    Kim, Woo-Il; Choi, Yong-Kyu; Lee, Jung-Ho; Park, Young-Han

    2014-01-01

    [Purpose] The aim of this study was to evaluate the changes in function and balance after Kinesio Taping application in stroke patients. [Subjects and Methods] Thirty subjects were randomly divided into an experimental group and control group. The experimental group was applied taping before therapeutic exercise, and the control group received only therapeutic exercise. Functional gait was measured using the straight line walking test, and dynamic balance ability was measured using the Berg Balance Scale. Walking velocity was measured with the 10 m walking test. [Results] There were statistically significant differences between the results of the straight line walking and 10 m walking tests in the pre-post analysis for the experimental group. There were a statistically significant difference in the Berg Balance Scale and 10 m walking test between the two groups. [Conclusion] Application of taping to the paralyzed parts of a stroke patient has a positive effect on improvement of typical asymmetric gait and walking speed. PMID:25435710

  1. A Pilot Study to Investigate Explosive Leg Extensor Power and Walking Performance After Stroke

    PubMed Central

    Dawes, Helen; Smith, Catherine; Collett, Johnny; Wade, Derick; Howells, Ken; Ramsbottom, Roger; Izadi, Hooshang; Sackley, Cath

    2005-01-01

    We examined explosive leg extensor power (LEP) and gait in men and women after a stroke using an experimental observational design. A convenience sample of consecutively referred individuals (8 men, 6 women) with chronic stroke mean age ± SD, range, 46.4 ± 8.4, 32 - 57 years, and able to walk for four minutes were recruited. The test re-test reliability and performance of LEP was measured together with walking parameters. LEP (Watts·kg-1) and gait measures during a four-minute walk; temporal-spatial gait parameters (GAITRite®) and oxygen cost of walking (mL·kg-1·m-1) were recorded. Percentage Asymmetry LEP (stronger LEP - weaker LEP/stronger LEP x 100) was calculated for each person. LEP was reliable from test to re-test ICC [3, 1] 0.8 - 0.7 (n = 9). Greater Asymmetry LEP correlated strongly with reduced walking velocity, cadence, stance time, and swing time on the weaker leg (n = 14) (p < 0.01). Findings demonstrate explosive LEP, in particular Percentage Asymmetry LEP, can be measured after stroke and is both reliable and related to walking performance. LEP training of the stronger or weaker leg warrants further investigation in this group. Key Points Explosive leg power (LEP) is a reliable measure in individuals recovering from a stroke. Significant asymmetry occurred in LEP in this group. Greater LEP asymmetry related to reduced walking performance after stroke. PMID:24501568

  2. Do relationships between environmental attributes and recreational walking vary according to area-level socioeconomic status?

    PubMed

    Sugiyama, Takemi; Howard, Natasha J; Paquet, Catherine; Coffee, Neil T; Taylor, Anne W; Daniel, Mark

    2015-04-01

    Residents of areas with lower socioeconomic status (SES) are known to be less physically active during leisure time. Neighborhood walkability has been shown to be related to recreational walking equally in low and high SES areas. This cross-sectional study tested whether associations of specific environmental attributes, measured objectively and subjectively, with walking for recreation were moderated by area-level SES. The data of the North West Adelaide Health Study collected in 2007 (n = 1500, mean age 57) were used. Self-reported walking frequency was the outcome of the study. Environmental exposure measures included objectively measured walkability components (residential density, intersection density, land use mix, and net retail area ratio) and perceived attributes (access to destinations, neighborhood esthetics, walking infrastructure, traffic/barriers, and crime safety). Participants' suburbs were categorized into low and high SES areas using an indicator of socioeconomic disadvantage. Low SES areas had lower scores in residential density, neighborhood esthetics, walking infrastructure, traffic/barriers, and crime safety. Recreational walking was associated with residential density, access to destinations, esthetics, traffic/barriers, and crime safety. Effect modification was observed for two attributes (out of nine): residential density was associated with walking only in low SES areas, while walking infrastructure was associated with walking only in high SES areas. The associations of neighborhood environmental attributes with recreational walking were largely consistent across SES groups. However, low SES areas were disadvantaged in most perceived environmental attributes related to recreational walking. Improving such attributes in low SES neighborhoods may help close socioeconomic disparities in leisure time physical activity.

  3. International Randomized Clinical Trial, Stroke Inpatient Rehabilitation With Reinforcement of Walking Speed (SIRROWS), Improves Outcomes

    PubMed Central

    Dobkin, Bruce H.; Plummer-D’Amato, Prudence; Elashoff, Robert; Lee, Jihey; Group, the SIRROWS

    2014-01-01

    Background Feedback about performance may optimize motor relearning after stroke. Objectives Develop an international collaboration to rapidly test the potential efficacy of daily verbal feedback about walking speed during inpatient rehabilitation after stroke, using a protocol that requires no research funds. Methods This phase 2, single-blinded, multicenter trial randomized inpatients to either feedback about self-selected fast walking speed (daily reinforcement of speed, DRS) immediately after a single, daily 10-m walk or to no reinforcement of speed (NRS) after the walk, performed within the context of routine physical therapy. The primary outcome was velocity for a 15.2-m (50-foot) timed walk at discharge. Secondary outcomes were walking distance in 3 minutes, length of stay (LOS), and level of independence (Functional Ambulation Classification, FAC). Results Within 18 months, 179 participants were randomized. The groups were balanced for age, gender, time from onset of stroke to entry, initial velocity, and level of walking-related disability. The walking speed at discharge for DRS (0.91 m/s) was greater (P = .01) than that for NRS (0.72 m/s). No difference was found for LOS. LOS for both DRS and NRS was significantly shorter, however, for those who had mean walking speeds >0.4 m/s at entry. The DRS group did not have a higher proportion of FAC independent walkers (P = .1) and did not walk longer distances (P = .09). Conclusions An Internet-based collaboration of 18 centers found that feedback about performance once a day produced gains in walking speed large enough to permit unlimited, slow community ambulation at discharge from inpatient rehabilitation. PMID:20164411

  4. Mentally walking through doorways causes forgetting: The location updating effect and imagination.

    PubMed

    Lawrence, Zachary; Peterson, Daniel

    2016-01-01

    Researchers have documented an intriguing phenomenon whereby simply walking through a doorway causes forgetting (the location updating effect). The Event Horizon Model is the most commonly cited theory to explain these data. Importantly, this model explains the effect without invoking the importance or reliance upon perceptual information (i.e., seeing oneself pass through the doorway). This generates the intriguing hypothesis that the effect may be demonstrated in participants who simply imagine walking through a doorway. Across two experiments, we explicitly test this hypothesis. Participants familiarised themselves with both real (Experiment 1) and virtual (Experiment 2) environments which served as the setting for their mental walk. They were then provided with an image to remember and were instructed to imagine themselves walking through the previously presented space. In both experiments, when the mental walk required participants to pass through a doorway, more forgetting occurred, consistent with the predictions laid out in the Event Horizon Model.

  5. Positive messaging promotes walking in older adults

    PubMed Central

    Notthoff, Nanna; Carstensen, Laura L.

    2014-01-01

    Walking is among the most cost-effective and accessible means of exercise. Mounting evidence suggests that walking may help to maintain physical and cognitive independence in old age by preventing a variety of health problems. However, older Americans fall far short of meeting the daily recommendations for walking. In two studies, we examined whether considering older adults’ preferential attention to positive information may effectively enhance interventions aimed at promoting walking. In Study 1, we compared the effectiveness of positive, negative, and neutral messages to encourage walking (as measured with pedometers). Older adults who were informed about the benefits of walking walked more than those who were informed about the negative consequences of failing to walk, whereas younger adults were unaffected by framing valence. In Study 2, we examined within-person change in walking in older adults in response to positively- or negatively-framed messages over a 28-day period. Once again, positively-framed messages more effectively promoted walking than negatively-framed messages, and the effect was sustained across the intervention period. Together, these studies suggest that consideration of age-related changes in preferences for positive and negative information may inform the design of effective interventions to promote healthy lifestyles. Future research is needed to examine the mechanisms underlying the greater effectiveness of positively as opposed to negatively framed messages and the generalizability of findings to other intervention targets and other subpopulations of older adults. PMID:24956001

  6. Segment lengths influence hill walking strategies.

    PubMed

    Sheehan, Riley C; Gottschall, Jinger S

    2014-08-22

    Segment lengths are known to influence walking kinematics and muscle activity patterns. During level walking at the same speed, taller individuals take longer, slower strides than shorter individuals. Based on this, we sought to determine if segment lengths also influenced hill walking strategies. We hypothesized that individuals with longer segments would display more joint flexion going uphill and more extension going downhill as well as greater lateral gastrocnemius and vastus lateralis activity in both directions. Twenty young adults of varying heights (below 155 cm to above 188 cm) walked at 1.25 m/s on a level treadmill as well as 6° and 12° up and downhill slopes while we collected kinematic and muscle activity data. Subsequently, we ran linear regressions for each of the variables with height, leg, thigh, and shank length. Despite our population having twice the anthropometric variability, the level and hill walking patterns matched closely with previous studies. While there were significant differences between level and hill walking, there were few hill walking variables that were correlated with segment length. In support of our hypothesis, taller individuals had greater knee and ankle flexion during uphill walking. However, the majority of the correlations were between tibialis anterior and lateral gastrocnemius activities and shank length. Contrary to our hypothesis, relative step length and muscle activity decreased with segment length, specifically shank length. In summary, it appears that individuals with shorter segments require greater propulsion and toe clearance during uphill walking as well as greater braking and stability during downhill walking.

  7. Neuromuscular determinants of maximum walking speed in well-functioning older adults.

    PubMed

    Clark, David J; Manini, Todd M; Fielding, Roger A; Patten, Carolynn

    2013-03-01

    groups tested, which included triceps surae (p=.44), quadriceps (p=.76) and hamstrings (p=.98). MG rate of EMG rise was positively associated with RFD and maximum 10m walking speed, but not the usual 10m walking speed. These findings support the conclusion that maximum walking speed is limited by impaired neuromuscular force and activation of the triceps surae muscle group. Future research should further evaluate the utility of maximum walking speed for use in clinical assessment to detect and monitor age-related functional decline.

  8. Does the COPD assessment test reflect functional status in patients with COPD?

    PubMed

    Gulart, Aline Almeida; Munari, Anelise Bauer; Queiroz, Ana Paula Adriano de; Cani, Katerine Cristhine; Matte, Darlan Laurício; Mayer, Anamaria Fleig

    2017-02-01

    The aim of this study was to investigate whether the chronic obstructive pulmonary disease (COPD) assessment test (CAT) reflects the functional status of patients with COPD. Forty-seven patients underwent anthropometric assessment, spirometry, the 6-minute walk test (6MWT), the Glittre-activity of daily living (ADL) test (TGlittre), the London Chest ADL (LCADL) scale, and the CAT. The total score of the CAT correlated with 6MWT distance, TGlittre time spent, and LCADL%total ( r = -0.56, 0.52, and 0.78, respectively; p < 0.05 for all). There was significant difference in 6MWT distance (490 ± 85.4 m vs. 387 ± 56.8 m), TGlittre time spent (3.67 ± 1.07 min vs. 5.03 ± 1.32 min), and LCADL%total (24.2 ± 3.02% vs. 44.4 ± 13.3%) between the low and high impacts of COPD on health status (respectively, p < 0.05 for all) as well as in the LCADL%total between medium and high impact of COPD on health status (31.3 ± 7.35% vs. 44.4 ± 13.3%; p = 0.001). In conclusion, the CAT reflects the functional status of patients with COPD.

  9. Assessing interactions among multiple physiological systems during walking outside a laboratory: An Android based gait monitor

    PubMed Central

    Sejdić, E.; Millecamps, A.; Teoli, J.; Rothfuss, M. A.; Franconi, N. G.; Perera, S.; Jones, A. K.; Brach, J. S.; Mickle, M. H.

    2015-01-01

    Gait function is traditionally assessed using well-lit, unobstructed walkways with minimal distractions. In patients with subclinical physiological abnormalities, these conditions may not provide enough stress on their ability to adapt to walking. The introduction of challenging walking conditions in gait can induce responses in physiological systems in addition to the locomotor system. There is a need for a device that is capable of monitoring multiple physiological systems in various walking conditions. To address this need, an Android-based gait-monitoring device was developed that enabled the recording of a patient's physiological systems during walking. The gait-monitoring device was tested during self-regulated overground walking sessions of fifteen healthy subjects that included 6 females and 9 males aged 18 to 35 years. The gait-monitoring device measures the patient's stride interval, acceleration, electrocardiogram, skin conductance and respiratory rate. The data is stored on an Android phone and is analyzed offline through the extraction of features in the time, frequency and time-frequency domains. The analysis of the data depicted multisystem physiological interactions during overground walking in healthy subjects. These interactions included locomotion-electrodermal, locomotion-respiratory and cardiolocomotion couplings. The current results depicting strong interactions between the locomotion system and the other considered systems (i.e., electrodermal, respiratory and cardivascular systems) warrant further investigation into multisystem interactions during walking, particularly in challenging walking conditions with older adults. PMID:26390946

  10. Oxygen cost of walking in persons with multiple sclerosis: disability matters, but why?

    PubMed

    Sandroff, Brian M; Klaren, Rachel E; Pilutti, Lara A; Motl, Robert W

    2014-01-01

    Background. The oxygen cost (O2 cost) of walking is elevated in persons with MS, particularly as a function of increasing disability status. Objective. The current study examined symptomatic (i.e., fatigue, pain, anxiety, and depression) and gait (i.e., velocity, cadence, and step length) variables that might explain why disability status is associated with O2 cost of walking in persons with MS. Materials and Methods. 82 participants completed the Patient-Determined Disease Steps, Fatigue Severity Scale, McGill Pain Questionnaire, and Hospital Anxiety and Depression Scale and undertook 2 trials of walking on a GAITRite electronic walkway. Participants then completed a six-minute walk test with concurrent assessment of expired gases for quantifying oxygen consumption and O2 cost of walking. Results. Disability (r = 0.55) as well as fatigue (r = 0.22), gait velocity (r = -0.62), cadence (r = -0.73), and step length (r = -0.53) were associated with the O2 cost of walking. Cadence (β = -0.67), but not step length (β = -0.14) or fatigue (β = -0.10), explained the association between disability and the O2 cost of walking. Conclusions. These results highlight cadence as a target of rehabilitation for increasing metabolic efficiency during walking among those with MS, particularly as a function of worsening disability.

  11. Oxygen Cost of Walking in Persons with Multiple Sclerosis: Disability Matters, but Why?

    PubMed Central

    Sandroff, Brian M.; Klaren, Rachel E.; Pilutti, Lara A.; Motl, Robert W.

    2014-01-01

    Background. The oxygen cost (O2 cost) of walking is elevated in persons with MS, particularly as a function of increasing disability status. Objective. The current study examined symptomatic (i.e., fatigue, pain, anxiety, and depression) and gait (i.e., velocity, cadence, and step length) variables that might explain why disability status is associated with O2 cost of walking in persons with MS. Materials and Methods. 82 participants completed the Patient-Determined Disease Steps, Fatigue Severity Scale, McGill Pain Questionnaire, and Hospital Anxiety and Depression Scale and undertook 2 trials of walking on a GAITRite electronic walkway. Participants then completed a six-minute walk test with concurrent assessment of expired gases for quantifying oxygen consumption and O2 cost of walking. Results. Disability (r = 0.55) as well as fatigue (r = 0.22), gait velocity (r = −0.62), cadence (r = −0.73), and step length (r = −0.53) were associated with the O2 cost of walking. Cadence (β = −0.67), but not step length (β = −0.14) or fatigue (β = −0.10), explained the association between disability and the O2 cost of walking. Conclusions. These results highlight cadence as a target of rehabilitation for increasing metabolic efficiency during walking among those with MS, particularly as a function of worsening disability. PMID:24734181

  12. Effects of Progressive Body Weight Support Treadmill Forward and Backward Walking Training on Stroke Patients’ Affected Side Lower Extremity’s Walking Ability

    PubMed Central

    Kim, Kyunghoon; Lee, Sukmin; Lee, Kyoungbo

    2014-01-01

    [Purpose] The purpose of the present study was to examine the effects of progressive body weight supported treadmill forward and backward walking training (PBWSTFBWT), progressive body weight supported treadmill forward walking training (PBWSTFWT), progressive body weight supported treadmill backward walking training (PBWSTBWT), on stroke patients’ affected side lower extremity’s walking ability. [Subjects and Methods] A total of 36 chronic stroke patients were divided into three groups with 12 subjects in each group. Each of the groups performed one of the progressive body weight supported treadmill training methods for 30 minute, six times per week for three weeks, and then received general physical therapy without any other intervention until the follow-up tests. For the assessment of the affected side lower extremity’s walking ability, step length of the affected side, stance phase of the affected side, swing phase of the affected side, single support of the affected side, and step time of the affected side were measured using optogait and the symmetry index. [Results] In the within group comparisons, all the three groups showed significant differences between before and after the intervention and in the comparison of the three groups, the PBWSTFBWT group showed more significant differences in all of the assessed items than the other two groups. [Conclusion] In the present study progressive body weight supported treadmill training was performed in an environment in which the subjects were actually walked, and PBWSTFBWT was more effective at efficiently training stroke patients’ affected side lower extremity’s walking ability. PMID:25540499

  13. Humans robustly adhere to dynamic walking principles by harnessing motor abundance to control forces.

    PubMed

    Toney, Megan E; Chang, Young-Hui

    2013-12-01

    Human walking dynamics are typically framed in the context of mechanics and energetics rather than in the context of neuromuscular control. Dynamic walking principles describe one helpful theoretical approach to characterize efficient human walking mechanics over many steps. These principles do not, however, address how such walking is controlled step-by-step despite small perturbations from natural variability. Our purpose was to identify neuromechanical control strategies used to achieve consistent and robust locomotion despite natural step-to-step force variability. We used the uncontrolled manifold concept to test whether human walkers select combinations of leading and trailing leg-forces that generate equivalent net-force trajectories during step-to-step transitions. Subjects selected leading and trailing leg-force combinations that generated consistent vertical net-force during step-to-step transitions. We conclude that vertical net-force is an implicit neuromechanical goal of human walking whose trajectory is stabilized for consistent step-to-step transitions, which agrees with the principles of dynamic walking. In contrast, inter-leg-force combinations modulated anterior-posterior net-force trajectories with each step to maintain constant walking speed, indicating that a consistent anterior-posterior net-force trajectory is not an implicit goal of walking. For a more complete picture of hierarchical locomotor control, we also tested whether each individual leg-force trajectory was stabilized through the selection of leg-force equivalent joint-torque combinations. The observed consistent vertical net-force trajectory was achieved primarily through the selection of joint-torque combinations that modulated trailing leg-force during step-to-step transitions. We conclude that humans achieve robust walking by harnessing inherent motor abundance of the joints and legs to maintain consistent step-by-step walking performance.

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

    PubMed Central

    Cong, Guang-Ting; Cohn, Matthew R.; Villa, Jordan; Kerwin, Lewis J.; Rosen, Natalie; Fang, Xiu Zhen; Christos, Paul J.; Evrony, Ayelet; Chen, Jin; Torres, Ashley; Lane, Joseph M.

    2015-01-01

    STRUCTURED ABSTRACT OBJECTIVES The literature increasingly demonstrates the importance of gait speed in the frailty assessment of patients 60 years and older. Conventional gait speed measurement, however, may be contraindicated in settings such as trauma where the patient is temporarily immobilized. We devised a Walking Speed Questionnaire (WSQ) to allow assessment of pre-injury baseline gait speed, 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 six physician-researchers. SETTING Four ambulatory clinics. PARTICIPANTS Ambulating individuals aged 60 to 95 (mean age 73.2 ± 8.1, 86.1% female, N = 101). INTERVENTION Participants completed the WSQ and underwent gait speed measurement for comparison. ANALYSIS WSQ score correlation to true gait speed, receiver operating characteristics, and validation statistics were performed. RESULTS All four questions of the WSQ independently predicted true gait speed significantly (P<0.001). The WSQ sufficiently predicted true gait speed with r = 0.696 and ρ = 0.717. CONCLUSION The WSQ is an effective tool for assessing baseline walking speed in patients 60 years and older in a self-reported manner. It permits gait screening in health care environments where conventional gait speed testing is contraindicated due to temporary immobilization, and may be used to provide baseline targets for goal-oriented post-trauma care. Given its ability to capture gait speed in patients who are unable to ambulate, it may open doors for frailty research in previously unattainable populations. PMID:26569186

  15. The QWalk simulator of quantum walks

    NASA Astrophysics Data System (ADS)

    Marquezino, F. L.; Portugal, R.

    2008-09-01

    Several research groups are giving special attention to quantum walks recently, because this research area have been used with success in the development of new efficient quantum algorithms. A general simulator of quantum walks is very important for the development of this area, since it allows the researchers to focus on the mathematical and physical aspects of the research instead of deviating the efforts to the implementation of specific numerical simulations. In this paper we present QWalk, a quantum walk simulator for one- and two-dimensional lattices. Finite two-dimensional lattices with generic topologies can be used. Decoherence can be simulated by performing measurements or by breaking links of the lattice. We use examples to explain the usage of the software and to show some recent results of the literature that are easily reproduced by the simulator. Program summaryProgram title: QWalk Catalogue identifier: AEAX_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAX_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 10 010 No. of bytes in distributed program, including test data, etc.: 172 064 Distribution format: tar.gz Programming language: C Computer: Any computer with a C compiler that accepts ISO C99 complex arithmetic (recent versions of GCC, for instance). Pre-compiled Windows versions are also provided Operating system: The software should run in any operating system with a recent C compiler. Successful tests were performed in Linux and Windows RAM: Less than 10 MB were required for a two-dimensional lattice of size 201×201. About 400 MB, for a two-dimensional lattice of size 1601×1601 Classification: 16.5 Nature of problem: Classical simulation of discrete quantum walks in one- and two-dimensional lattices. Solution method: Iterative approach without explicit representation of

  16. Walking Speed: The Functional Vital Sign

    PubMed Central

    Middleton, Addie; Fritz, Stacy L.; Lusardi, Michelle

    2014-01-01

    Walking speed (WS) is a valid, reliable, sensitive measure appropriate for assessing and monitoring functional status and overall health in a wide range of populations. These capabilities have led to its designation as the “6th vital sign”. By synthesizing the available evidence on WS, this scholarly review article provides clinicians with a reference tool regarding this robust measure. Recommendations on testing procedures for assessing WS, including optimal distance, inclusion of acceleration/deceleration phases, instructions, and instrumentation are given. After assessing an individual’s WS, clinicians need to know what this value represents. Therefore, WS cut-off values and the corresponding predicted outcomes, as well as minimal detectable change values for specific populations and settings are provided. PMID:24812254

  17. Quantum walks with random phase shifts

    SciTech Connect

    Kosik, Jozef; Buzek, Vladimir; Hillery, Mark

    2006-08-15

    We investigate quantum walks in multiple dimensions with different quantum coins. We augment the model by assuming that at each step the amplitudes of the coin state are multiplied by random phases. This model enables us to study in detail the role of decoherence in quantum walks and to investigate the quantum-to-classical transition. We also provide classical analog of the quantum random walks studied. Interestingly enough, it turns out that the classical counterparts of some quantum random walks are classical random walks with a memory and biased coin. In addition random phase shifts 'simplify' the dynamics (the cross-interference terms of different paths vanish on average) and enable us to give a compact formula for the dispersion of such walks.

  18. [Recovery of walk in persons with stroke and heart disease].

    PubMed

    Kapidzić-Duraković, Suada; Karabegović, Azra; Zonić-Imamović, Majda

    2006-01-01

    The goal of this research is to analyze the differences in recovery of walk of two groups of patients who have suffered the stroke--those who have and have not suffered from heart disease prior to the stroke. Test group consisted of patients who have suffered the stroke, and have been rehabilitated in the Clinic for physical medicine and rehabilitation in Tuzla, in 2003. Patients who have had a heart disease before suffering the stroke and have been treated by a cardiologist comprised the first test group (Group I, N=48), while patients without previous heart disease comprised the second test group (Group II, N=69). In relation to their ability to walk, patients have been divided into three groups: those who are able to walk without help, those who are not able to walk and those who are able to walk with a walking aid. Therapies used include kinesiotherapy, paraffin, criotherapy, and electro procedures. Total number of those rehabilitated in the hospital after the stroke is 117, out of which 45 (38.5 %) were women and 72 (61.5 %) men, with average of 68 +/- 9,2 years of age. According to the kind of stroke suffered, 105 patients have had ischemia (89.7 %) and 12 have had hemorrhagia (10.3 %). The highest number of patients have had paralysis of the left side of the body--48 (41.0 %), then paralysis of the right side--43 (36.8 %) and both sides--15 (12.8 %). In relation to the localization of the changes in the brain detected in the CT, the highest number of patients have had multiply lacunar changes--41 (35,0 %), then changes in parietal area--33 (28.2 %) and temporoparietal area--22 (18.8 %), and a bit less had changes in capsula interna--15 (12.8 %), occipital--3 (2.6 %) and cerebellum--3 (2.6 %). In relation to the heart diseases, most of the patients have had compensated weakness of the heart--20 (41.7 %), suffered infarctus myocardii--8 (16.7 %) and atrial fibrillation--8 (16.7 %), with angina pectoris 6 (12,5 %), with arrhitmia--3 (6.3 %) and heart surgery--3

  19. Walking difficulties in patients with Alzheimer's disease might originate from gait apraxia

    PubMed Central

    Della, S; Spinnler, H; Venneri, A

    2004-01-01

    Objectives: To investigate whether gait apraxia is a possible cause for some of the walking abnormalities shown by patients with Alzheimer's disease. Methods: 60 patients with Alzheimer's disease, selected as being free from overt extrapyramidal impairment or other potential causes of walking deficits, were assessed with a new test evaluating aspects of walking and related movements. Norms for this test were collected from a sample of 182 healthy volunteers. Results: 40% of the Alzheimer group performed below the cut off score on this test, and half performed poorly. Performance of the Alzheimer group in the walking skills test correlated highly with scores in a test assessing limb apraxia and with dementia severity. Conclusions: Gait apraxia may be the cause of walking disorders found in a subgroup of patients with Alzheimer's disease. Its detection is made easier by the use of a standardised test, but still relies heavily on the exclusion of other causes of walking deficits. It is a recognisable and independent form of apraxia. PMID:14742586

  20. Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor.

    PubMed

    Kivell, Tracy L; Schmitt, Daniel

    2009-08-25

    Despite decades of debate, it remains unclear whether human bipedalism evolved from a terrestrial knuckle-walking ancestor or from a more generalized, arboreal ape ancestor. Proponents of the knuckle-walking hypothesis focused on the wrist and hand to find morphological evidence of this behavior in the human fossil record. These studies, however, have not examined variation or development of purported knuckle-walking features in apes or other primates, data that are critical to resolution of this long-standing debate. Here we present novel data on the frequency and development of putative knuckle-walking features of the wrist in apes and monkeys. We use these data to test the hypothesis that all knuckle-walking apes share similar anatomical features and that these features can be used to reliably infer locomotor behavior in our extinct ancestors. Contrary to previous expectations, features long-assumed to indicate knuckle-walking behavior are not found in all African apes, show different developmental patterns across species, and are found in nonknuckle-walking primates as well. However, variation among African ape wrist morphology can be clearly explained if we accept the likely independent evolution of 2 fundamentally different biomechanical modes of knuckle-walking: an extended wrist posture in an arboreal environment (Pan) versus a neutral, columnar hand posture in a terrestrial environment (Gorilla). The presence of purported knuckle-walking features in the hominin wrist can thus be viewed as evidence of arboreality, not terrestriality, and provide evidence that human bipedalism evolved from a more arboreal ancestor occupying the ecological niche common to all living apes.

  1. Quantum walk with one variable absorbing boundary

    NASA Astrophysics Data System (ADS)

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

    2017-01-01

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks.

  2. Visual Acuity During Treadmill Walking

    NASA Technical Reports Server (NTRS)

    Peters, B. T.; Brady, R.; vanEmmerik, R. E. A.; Bloomberg, Jacob J.

    2006-01-01

    An awareness of the physical world is essential for successful navigation through the environment. Vision is the means by which this awareness is made possible for most people. However, without adequate compensation, the movements of the body during walking could impair vision. Previous research has shown how the eyes, head and trunk movements are coordinated to provide the compensation necessary for clear vision, but the overall effectiveness of these coordinated movements is unknown. The goal of the research presented here was to provide a direct measure of visual performance during locomotion, while also investigating the degree to which coordinated head and body movements can be altered to facilitate the goal of seeing clearly.

  3. Quantum Walks with Encrypted Data

    NASA Astrophysics Data System (ADS)

    Rohde, Peter P.; Fitzsimons, Joseph F.; Gilchrist, Alexei

    2012-10-01

    In the setting of networked computation, data security can be a significant concern. Here we consider the problem of allowing a server to remotely manipulate client supplied data, in such a way that both the information obtained by the client about the server’s operation and the information obtained by the server about the client’s data are significantly limited. We present a protocol for achieving such functionality in two closely related models of restricted quantum computation—the boson sampling and quantum walk models. Because of the limited technological requirements of the boson scattering model, small scale implementations of this technique are feasible with present-day technology.

  4. The Recovery of Walking in Stroke Patients: A Review

    ERIC Educational Resources Information Center

    Jang, Sung Ho

    2010-01-01

    We reviewed the literature on walking recovery of stroke patients as it relates to the following subjects: epidemiology of walking dysfunction, recovery course of walking, and recovery mechanism of walking (neural control of normal walking, the evaluation methods for leg motor function, and motor recovery mechanism of leg). The recovery of walking…

  5. Protein localization prediction using random walks on graphs

    PubMed Central

    2013-01-01

    Background Understanding the localization of proteins in cells is vital to characterizing their functions and possible interactions. As a result, identifying the (sub)cellular compartment within which a protein is located becomes an important problem in protein classification. This classification issue thus involves predicting labels in a dataset with a limited number of labeled data points available. By utilizing a graph representation of protein data, random walk techniques have performed well in sequence classification and functional prediction; however, this method has not yet been applied to protein localization. Accordingly, we propose a novel classifier in the site prediction of proteins based on random walks on a graph. Results We propose a graph theory model for predicting protein localization using data generated in yeast and gram-negative (Gneg) bacteria. We tested the performance of our classifier on the two datasets, optimizing the model training parameters by varying the laziness values and the number of steps taken during the random walk. Using 10-fold cross-validation, we achieved an accuracy of above 61% for yeast data and about 93% for gram-negative bacteria. Conclusions This study presents a new classifier derived from the random walk technique and applies this classifier to investigate the cellular localization of proteins. The prediction accuracy and additional validation demonstrate an improvement over previous methods, such as support vector machine (SVM)-based classifiers. PMID:23815126

  6. Origin of human bipedalism: The knuckle-walking hypothesis revisited.

    PubMed

    Richmond, B G; Begun, D R; Strait, D S

    2001-01-01

    Some of the most long-standing questions in paleoanthropology concern how and why human bipedalism evolved. Over the last century, many hypotheses have been offered on the mode of locomotion from which bipedalism originated. Candidate ancestral adaptations include monkey-like arboreal or terrestrial quadrupedalism, gibbon- or orangutan-like (or other forms of) climbing and suspension, and knuckle-walking. This paper reviews the history of these hypotheses, outlines their predictions, and assesses them in light of current phylogenetic, comparative anatomical, and fossil evidence. The functional significance of characteristics of the shoulder and arm, elbow, wrist, and hand shared by African apes and humans, including their fossil relatives, most strongly supports the knuckle-walking hypothesis, which reconstructs the ancestor as being adapted to knuckle-walking and arboreal climbing. Future fossil discoveries, and a clear understanding of anthropoid locomotor anatomy, are required to ultimately test these hypotheses. If knuckle-walking was an important component of the behavioral repertoire of the prebipedal human ancestor, then we can reject scenarios on the origin of bipedalism that rely on a strictly arboreal ancestor. Moreover, paleoenvironmental data associated with the earliest hominins, and their close relatives, contradict hypotheses that place the agents of selection for bipedality in open savanna habitats. Existing hypotheses must explain why bipedalism would evolve from an ancestor that was already partly terrestrial. Many food acquisition and carrying hypotheses remain tenable in light of current evidence.

  7. IMU-based ambulatory walking speed estimation in constrained treadmill and overground walking.

    PubMed

    Yang, Shuozhi; Li, Qingguo

    2012-01-01

    This study evaluated the performance of a walking speed estimation system based on using an inertial measurement unit (IMU), a combination of accelerometers and gyroscopes. The walking speed estimation algorithm segments the walking sequence into individual stride cycles (two steps) based on the inverted pendulum-like behaviour of the stance leg during walking and it integrates the angular velocity and linear accelerations of the shank to determine the displacement of each stride. The evaluation was performed in both treadmill and overground walking experiments with various constraints on walking speed, step length and step frequency to provide a relatively comprehensive assessment of the system. Promising results were obtained in providing accurate and consistent walking speed/step length estimation in different walking conditions. An overall percentage root mean squared error (%RMSE) of 4.2 and 4.0% was achieved in treadmill and overground walking experiments, respectively. With an increasing interest in understanding human walking biomechanics, the IMU-based ambulatory system could provide a useful walking speed/step length measurement/control tool for constrained walking studies.

  8. Exploiting Interlimb Arm and Leg Connections for Walking Rehabilitation: A Training Intervention in Stroke

    PubMed Central

    Kaupp, Chelsea; Zehr, E. Paul

    2016-01-01

    Rhythmic arm and leg (A&L) movements share common elements of neural control. The extent to which A&L cycling training can lead to training adaptations which transfer to improved walking function remains untested. The purpose of this study was to test the efficacy of A&L cycling training as a modality to improve locomotor function after stroke. Nineteen chronic stroke (>six months) participants were recruited and performed 30 minutes of A&L cycling training three times a week for five weeks. Changes in walking function were assessed with (1) clinical tests; (2) strength during isometric contractions; and (3) treadmill walking performance and cutaneous reflex modulation. A multiple baseline (3 pretests) within-subject control design was used. Data show that A&L cycling training improved clinical walking status increased strength by ~25%, improved modulation of muscle activity by ~25%, increased range of motion by ~20%, decreased stride duration, increased frequency, and improved modulation of cutaneous reflexes during treadmill walking. On most variables, the majority of participants showed a significant improvement in walking ability. These results suggest that exploiting arm and leg connections with A&L cycling training, an accessible and cost-effective training modality, could be used to improve walking ability after stroke. PMID:27403344

  9. The effects of knee arthroplasty on walking speed: A meta-analysis

    PubMed Central

    2012-01-01

    Background Patients with knee osteoarthritis patients have problems with walking, and tend to walk slower. An important aim of knee arthroplasty is functional recovery, which should include a post-operative increase in walking speed. Still, there are several problems with measuring walking speed in groups of knee osteoarthritis patients. Nevertheless, test-retest reliability of walking speed measurements is high, and when the same investigators monitor the same subjects, it should be possible to assess the walking speed effects of knee arthroplasty. The present study reports a meta-analysis of these effects. Methods A total of 16 independent pre-post arthroplasty comparisons of walking speed were identified through MEDLINE, Web of Science, and PEDro, in 12 papers, involving 419 patients. Results For 0.5–5 months post-operatively, heterogeneity was too large to obtain a valid estimate of the overall effect-size. For 6–12 and 13–60 months post-operatively, heterogeneity was absent, low, or moderate (depending on estimated pre-post correlations). During these periods, subjects walked on average 0.8 standard-deviations faster than pre-operatively, which is a large effect. Meta-regression analysis revealed significant effects of time and time squared, suggesting initial improvement followed by decline. Conclusion This meta-analysis revealed a large effect of arthroplasty on walking speed 6–60 months post-operatively. For the first 0.5–5 months, heterogeneity of effect-sizes precluded a valid estimate of short-term effects. Hence, patients may expect a considerable improvement of their walking speed, which, however, may take several months to occur. Meta-regression analysis suggested a small decline from 13 months post-operatively onwards. PMID:22559793

  10. Walking Performance: Correlation between Energy Cost of Walking and Walking Participation. New Statistical Approach Concerning Outcome Measurement

    PubMed Central

    Franceschini, Marco; Rampello, Anais; Agosti, Maurizio; Massucci, Maurizio; Bovolenta, Federica; Sale, Patrizio

    2013-01-01

    Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW), in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS). One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance. PMID:23468871

  11. Interface Reconstruction with Directional Walking

    SciTech Connect

    Yao, J

    2009-05-22

    Young's interface reconstruction with three-dimensional arbitrary mesh, in general, is rather tedious to implement compared to the case of a regular mesh. The main difficulty comes from the construction of a planar facet that bounds a certain volume inside a cell. Unlike the five basic configurations with a Cartesian mesh, there can be a great number of different configurations in the case of a general mesh. We represent a simple method that can derive the topology/geometry of the intersection of arbitrary planar objects in a uniform way. The method is based on a directional walking on the surface of objects, and links the intersection points with the paths of the walking naturally defining the intersection of objects. The method works in both two and three dimensions. The method does not take advantage of convexity, thus decomposition of an object is not necessary. Therefore, the solution with this method will have a reduced number of edges and less data storage, compared with methods that use shape decomposition. The treatment is general for arbitrary polyhedrons, and no look-up tables are needed. The same operation can easily be extended for curved geometry. The implementation of this new algorithm shall allow the interface reconstruction on an arbitrary mesh to be as simple as it is on a regular mesh. Furthermore, we exactly compute the integral of partial cell volume bounded by quadratic interface. Therefore, interface reconstruction with higher than second order accuracy can be achieved on an arbitrary mesh.

  12. Quantum walk on a cylinder

    NASA Astrophysics Data System (ADS)

    Bru, Luis A.; de Valcárcel, Germán J.; Di Molfetta, Giuseppe; Pérez, Armando; Roldán, Eugenio; Silva, Fernando

    2016-09-01

    We consider the two-dimensional alternate quantum walk on a cylinder. We concentrate on the study of the motion along the open dimension, in the spirit of looking at the closed coordinate as a small or "hidden" extra dimension. If one starts from localized initial conditions on the lattice, the dynamics of the quantum walk that is obtained after tracing out the small dimension shows the contribution of several components which can be understood from the study of the dispersion relations for this problem. In fact, these components originate from the contribution of the possible values of the quasimomentum in the closed dimension. In the continuous space-time limit, the different components manifest as a set of Dirac equations, with each quasimomentum providing the value of the corresponding mass. We briefly discuss the possible link of these ideas to the simulation of high-energy physical theories that include extra dimensions. Finally, entanglement between the coin and spatial degrees of freedom is studied, showing that the entanglement entropy clearly overcomes the value reached with only one spatial dimension.

  13. Is the 1-minute sit-to-stand test a good tool for the evaluation of the impact of pulmonary rehabilitation? Determination of the minimal important difference in COPD

    PubMed Central

    Vaidya, Trija; de Bisschop, Claire; Beaumont, Marc; Ouksel, Hakima; Jean, Véronique; Dessables, François; Chambellan, Arnaud

    2016-01-01

    Background The 1-minute sit-to-stand (STS) test could be valuable to assess the level of exercise tolerance in chronic obstructive pulmonary disease (COPD). There is a need to provide the minimal important difference (MID) of this test in pulmonary rehabilitation (PR). Methods COPD patients undergoing the 1-minute STS test before PR were included. The test was performed at baseline and the end of PR, as well as the 6-minute walk test, and the quadriceps maximum voluntary contraction (QMVC). Home and community-based programs were conducted as recommended. Responsiveness to PR was determined by the difference in the 1-minute STS test between baseline and the end of PR. The MID was evaluated using distribution and anchor-based methods. Results Forty-eight COPD patients were included. At baseline, the significant predictors of the number of 1-minute STS repetitions were the 6-minute walk distance (6MWD) (r=0.574; P<10−3), age (r=−0.453; P=0.001), being on long-term oxygen treatment (r=−0.454; P=0.017), and the QMVC (r=0.424; P=0.031). The multivariate analysis explained 75.8% of the variance of 1-minute STS repetitions. The improvement of the 1-minute STS repetitions at the end of PR was 3.8±4.2 (P<10−3). It was mainly correlated with the change in QMVC (r=0.572; P=0.004) and 6MWD (r=0.428; P=0.006). Using the distribution-based analysis, an MID of 1.9 (standard error of measurement method) or 3.1 (standard deviation method) was found. With the 6MWD as anchor, the receiver operating characteristic curve identified the MID for the change in 1-minute STS repetitions at 2.5 (sensibility: 80%, specificity: 60%) with area under curve of 0.716. Conclusion The 1-minute STS test is simple and sensitive to measure the efficiency of PR. An improvement of at least three repetitions is consistent with physical benefits after PR. PMID:27799759

  14. Walking activities and wear of prostheses.

    PubMed Central

    Seedhom, B B; Wallbridge, N C

    1985-01-01

    A study of the walking activities of 243 individuals was carried out. The individuals came from four different occupations and had an age range of 17-83 years. The survey carried out in this investigation showed surprisingly little correlation between variables such as age, height, and weight of individuals and their speed of walking, length of stride, or distance walked. Correlation matrices were obtained for the whole sample and then for each sex, showing similar trends. The most significant correlation was between the height of an individual and the length of the stride, and there was a lesser correlation between age and the number of steps walked by an individual per day. Further statistical analyses showed that males in manual occupations walked most and those in sedentary occupations walked least. On the other hand, in the female groups housewives seemed to walk least and those in technical occupations walked most. The average number of steps walked per day by a male individual for the whole sample was 9537; that for females was 9839. The corresponding distances walked per day were 6.7 and 6.5 km. The differences were not statistically significant. Predictions of wear of prosthetic components made of ultrahigh molecular weight polyethylene were made on the basis of the above data and other variables affecting wear, such as the weight of the subject and the area available for contact during walking. Charts have been constructed of the penetration of the metallic component into the plastic one for both hip knee prostheses, thus enabling predictions of the wear of the plastic components of these two most widely used prostheses. Owing to the wide ranging values of the variables used in making the predictions of wear, these latter should be regarded only as 'safe' first estimates. PMID:4083940

  15. Walking...A Step in the Right Direction!

    MedlinePlus

    ... 3. Go Divide your walk into three parts: Warm up by walking slowly. Increase your speed to a ... stretching only after you have warmed up. To warm up, walk slowly for a few minutes before picking ...

  16. Walking economy in people with Parkinson's disease

    PubMed Central

    Christiansen, Cory L; Schenkman, Margaret L; McFann, Kim; Wolfe, Pamela; Kohrt, Wendy M

    2009-01-01

    Gait dysfunction is an early problem identified by patients with Parkinson's disease (PD). Alterations in gait may result in an increase in the energy cost of walking (i.e., walking economy). The purpose of this study was to determine whether walking economy is atypical in patients with PD when compared with healthy controls. A secondary purpose was to evaluate the associations of age, sex, and level of disease severity with walking economy in patients with PD. The rate of oxygen consumption (VO2) and other responses to treadmill walking were compared in 90 patients (64.4±10.3 yr) and 44 controls (64.6±7.3 yr) at several walking speeds. Pearson correlation coefficients (r) were calculated to determine relationships of age, sex, and disease state with walking economy in PD patients. Walking economy was significantly worse in PD patients than in controls at all speeds above 1.0 mph. Across all speeds, VO2 was 6 to 10% higher in PD patients. Heart rate, minute ventilation, respiratory exchange ratio, and rating of perceived exertion were correspondingly elevated. No significant relationship of age, sex, or UPDRS score with VO2 was found for patients with PD. The findings suggest that the physiologic stress of daily physical activities is increased in patients with early to mid-stage PD, and this may contribute to the elevated level of fatigue that is characteristic of PD. PMID:19441128

  17. Quantum random walks and decision making.

    PubMed

    Shankar, Karthik H

    2014-01-01

    How realistic is it to adopt a quantum random walk model to account for decisions involving two choices? Here, we discuss the neural plausibility and the effect of initial state and boundary thresholds on such a model and contrast it with various features of the classical random walk model of decision making.

  18. Welly-Walks for Science Learning

    ERIC Educational Resources Information Center

    Fradley, Carol

    2006-01-01

    This article discusses how a regular walk in the wind or the rain can help develop science knowledge and skills. The author describes one "welly-walk" and links it to National Curriculum for England requirements so that readers can see how easy it is. (Contains 1 figure and 1 box.)

  19. Chinese City Children and Youth's Walking Behavior

    ERIC Educational Resources Information Center

    Quan, Minghui; Chen, Peijie; Zhuang, Jie; Wang, Chao

    2013-01-01

    Purpose: Although walking has been demonstrated as one of the best forms for promoting physical activity (PA), little is known about Chinese city children and youth's walking behavior. The purpose of this study was therefore to assess ambulatory PA behavior of Chinese city children and youth. Method: The daily steps of 2,751 children and youth…

  20. Quantum vs. classical walks with memory two

    NASA Astrophysics Data System (ADS)

    Dimcovic, Zlatko; Kovchegov, Yevgeniy

    2010-03-01

    Quantum walks is an emerging field in quantum computing. It is expected to become the next most effective tool in speeding up quantum algorithms, possibly achieving the similar gain in speed as was the case with Gibbs sampling in classical computing. There already exist examples of super-exponential speed up using only quantum walks. Markov chains, or random walks on graphs, have many uses in physics; and walks with memory are standard models for a number of phenomena. We study persistent quantum walks, and compare them with equivalent classical Markov processes. The first question to ask is how the mixing time compares between persistent quantum and classical walks. Since quantum walks are generated by unitary matrices, they do not converge to a stationary state. The mixing time is then naturally introduced via a limiting distribution defined as the average of the probability distributions over time (Cesaro sum). We compare the mixing times, along with other properties, using numerical methods and spectral analysis. Our preliminary results indicate a significant speedup in some cases, and a number of other interesting aspects of quantum walks.

  1. Motor Fatigue Measurement by Distance-Induced Slow Down of Walking Speed in Multiple Sclerosis

    PubMed Central

    Phan-Ba, Rémy; Calay, Philippe; Grodent, Patrick; Delrue, Gael; Lommers, Emilie; Delvaux, Valérie; Moonen, Gustave; Belachew, Shibeshih

    2012-01-01

    Background and rationale Motor fatigue and ambulation impairment are prominent clinical features of people with multiple sclerosis (pMS). We hypothesized that a multimodal and comparative assessment of walking speed on short and long distance would allow a better delineation and quantification of gait fatigability in pMS. Our objectives were to compare 4 walking paradigms: the timed 25-foot walk (T25FW), a corrected version of the T25FW with dynamic start (T25FW+), the timed 100-meter walk (T100MW) and the timed 500-meter walk (T500MW). Methods Thirty controls and 81 pMS performed the 4 walking tests in a single study visit. Results The 4 walking tests were performed with a slower WS in pMS compared to controls even in subgroups with minimal disability. The finishing speed of the last 100-meter of the T500MW was the slowest measurable WS whereas the T25FW+ provided the fastest measurable WS. The ratio between such slowest and fastest WS (Deceleration Index, DI) was significantly lower only in pMS with EDSS 4.0–6.0, a pyramidal or cerebellar functional system score reaching 3 or a maximum reported walking distance ≤4000 m. Conclusion The motor fatigue which triggers gait deceleration over a sustained effort in pMS can be measured by the WS ratio between performances on a very short distance and the finishing pace on a longer more demanding task. The absolute walking speed is abnormal early in MS whatever the distance of effort when patients are unaware of ambulation impairment. In contrast, the DI-measured ambulation fatigability appears to take place later in the disease course. PMID:22514661

  2. Correlation analysis of visual analogue scale and measures of walking ability in multiple sclerosis patients.

    PubMed

    Filipović Grčić, Petar; Matijaca, Meri; Bilić, Ivica; Džamonja, Gordan; Lušić, Ivo; Čaljkušić, Krešimir; Čapkun, Vesna

    2013-12-01

    Walking limitation assessment in multiple sclerosis patients (MSPs) is a demanding task, especially in the clinical setting. The aim of this study is to correlate the visual analogue scale (VAS), a simple method for measuring subjective experience, with measures of walking ability used in clinical research of MS. The study included 82 ambulatory MSPs who have resided in the local community. The applied measures of walking ability were the following: the single-item and patient-rated Walking Ability Visual Analogue Scale (WA-VAS), the Expanded Disability Status Scale (EDSS), the 25-foot walk test (25FWT), the Six Spot Step Test (SSST), the 2 min timed walk (2 min TW), the Multiple Sclerosis Walking Scale-12 (MSWS-12), and step activity monitor accelerometer (SAM) during 7 day period. The SAM analysis included the average daily step count, the average steps/min of the highest 1 min of a day, and the average steps/min of the highest continuous 60 min of a day. The WA-VAS scores significantly and strongly correlated with EDSS (ρ = 0.679, P < 0.001), 25FWT (ρ = 0.606, P < 0.001), SSST (ρ = 0.729, P < 0.001), 2 min TW (ρ = -0.643, P < 0.001), MSWS-12 (ρ = 0.746, P < 0.001), average daily step count (ρ = -0.507, P < 0.001), average steps/min of the highest 1 min of a day (ρ = -0.544, P < 0.001), and average steps/min of the highest continuous 60 min of a day (ρ = -0.473, P < 0.001). Correlations between WA-VAS and measures of walking ability used in clinical research of MS were satisfactory. The results obtained in this research indicate that the WA-VAS could be an instrument for simple measurement of walking limitations in MSPs in the clinical setting.

  3. The impact of dynamic balance measures on walking performance in multiple sclerosis

    PubMed Central

    Fritz, Nora E.; Marasigan, Rhul Evans R.; Calabresi, Peter A.; Newsome, Scott D.; Zackowski, Kathleen M.

    2014-01-01

    Background Static posture imbalance and gait dysfunction are common in individuals with multiple sclerosis (MS). Although the impact of strength and static balance on walking has been examined, little is known about the impact of dynamic standing balance on walking in MS. Objective To determine the impact of dynamic balance, static balance, sensation, and strength measures to walking in individuals with MS. Methods 52 individuals with MS (27 females; 26 relapsing-remitting; mean age 45.6±10.3 years; median EDSS 3.5 (range 0-7) participated in testing for dynamic and static posturography (Kistler 9281 force plate), hip flexion, hip extension, and ankle dorsiflexion strength (Microfet2 hand-held dynamometer), sensation (Vibratron II) and walk velocity (Optotrak Motion Analysis System). Mann-Whitney tests, Spearman correlation coefficients, and forward stepwise multiple regression were used to assess statistical significance. Results All measures were significantly abnormal in MS subjects when compared to age and sex-matched norms (p<0.05 for all). Static balance (eyes open, feet together [EOFT]), anterior- posterior (AP) dynamic sway, and hip extension strength were strongly correlated with fast walking velocity (AP sway r=0.68; hip extension strength r=0.73; EOFT r=-0.40). Together, AP dynamic sway (ρr=0.71, p<0.001), hip extension strength (ρr=0.54, p<0.001), and EOFT static balance (ρr=-0.41, p=0.01) explained more than 70% of the variance in fast walking velocity (p<0.001). Conclusions These data suggest that AP dynamic sway impacts walking performance in MS. A combined evaluation of dynamic balance, static balance and strength may lead to a better understanding of walking mechanisms as well as the development of strategies to improve walking. PMID:24795162

  4. Modular control of human walking: a simulation study.

    PubMed

    Neptune, Richard R; Clark, David J; Kautz, Steven A

    2009-06-19

    Recent evidence suggests that performance of complex locomotor tasks such as walking may be accomplished using a simple underlying organization of co-active muscles, or "modules", which have been assumed to be structured to perform task-specific biomechanical functions. However, no study has explicitly tested whether the modules would actually produce the biomechanical functions associated with them or even produce a well-coordinated movement. In this study, we generated muscle-actuated forward dynamics simulations of normal walking using muscle activation modules (identified using non-negative matrix factorization) as the muscle control inputs to identify the contributions of each module to the biomechanical sub-tasks of walking (i.e., body support, forward propulsion, and leg swing). The simulation analysis showed that a simple neural control strategy involving five muscle activation modules was sufficient to perform the basic sub-tasks of walking. Module 1 (gluteus medius, vasti, and rectus femoris) primarily contributed to body support in early stance while Module 2 (soleus and gastrocnemius) contributed to both body support and propulsion in late stance. Module 3 (rectus femoris and tibialis anterior) acted to decelerate the leg in early and late swing while generating energy to the trunk throughout swing. Module 4 (hamstrings) acted to absorb leg energy (i.e., decelerate it) in late swing while increasing the leg energy in early stance. Post-hoc analysis revealed an additional module (Module 5: iliopsoas) acted to accelerate the leg forward in pre- and early swing. These results provide evidence that the identified modules can act as basic neural control elements that generate task-specific biomechanical functions to produce well-coordinated walking.

  5. Estimation of detection thresholds for redirected walking techniques.

    PubMed

    Steinicke, Frank; Bruder, Gerd; Jerald, Jason; Frenz, Harald; Lappe, Markus

    2010-01-01

    In immersive virtual environments (IVEs), users can control their virtual viewpoint by moving their tracked head and walking through the real world. Usually, movements in the real world are mapped one-to-one to virtual camera motions. With redirection techniques, the virtual camera is manipulated by applying gains to user motion so that the virtual world moves differently than the real world. Thus, users can walk through large-scale IVEs while physically remaining in a reasonably small workspace. In psychophysical experiments with a two-alternative forced-choice task, we have quantified how much humans can unknowingly be redirected on physical paths that are different from the visually perceived paths. We tested 12 subjects in three different experiments: (E1) discrimination between virtual and physical rotations, (E2) discrimination between virtual and physical straightforward movements, and (E3) discrimination of path curvature. In experiment E1, subjects performed rotations with different gains, and then had to choose whether the visually perceived rotation was smaller or greater than the physical rotation. In experiment E2, subjects chose whether the physical walk was shorter or longer than the visually perceived scaled travel distance. In experiment E3, subjects estimate the path curvature when walking a curved path in the real world while the visual display shows a straight path in the virtual world. Our results show that users can be turned physically about 49 percent more or 20 percent less than the perceived virtual rotation, distances can be downscaled by 14 percent and upscaled by 26 percent, and users can be redirected on a circular arc with a radius greater than 22 m while they believe that they are walking straight.

  6. The role of crawling and walking experience in infant spatial memory.

    PubMed

    Clearfield, M W

    2004-11-01

    This research explored infants' use of place learning and cue learning in a locomotor task across the transition from crawling to walking. Novice and expert crawling and walking infants were observed in a novel locomotor task-finding a hidden goal location in a large space. In Experiment 1, infants were tested with distal landmarks. Infants with fewer than 6 weeks of experience, either crawling or walking, could not find the goal location. All infants with more locomotor experience were more successful. Learning did not transfer across the transition to walking. In Experiment 2, novice and expert crawlers and walkers were tested with a direct landmark. Again, novice crawlers and walkers with fewer than 6 weeks of experience could not find the goal, whereas those with more experience could. Taken together, these findings suggest that infants' spatial learning is inextricably linked to mode of locomotion.

  7. Effects of proprioceptive sense-based Kinesio taping on walking imbalance

    PubMed Central

    Park, Young-Han; Lee, Jung-Ho

    2016-01-01

    [Purpose] The aim of this study was to determine how application of Kinesio tape to the upper and lower limbs affects walking through stimulation of the proprioceptive sense. [Subjects and Methods] Twelve patients diagnosed with hemiplegia due to stroke were selected as the subjects of the study. To ascertain the effects of Kinesio taping on walking, all subjects performed a straight line walking test three times while barefoot. In terms of the actual taping application, elastic Kinesio tape was used on the hemiplegic side in all subjects. [Results] The results of testing showed a significant difference in the values between before and after taping. In terms of left and right deviation according to the site of the taping application, there were statistically significant differences among the groups. [Conclusion] In conclusion, application of Kinesio taping for central nerve injury was confirmed to be effective in reducing walking deviation. PMID:27942119

  8. Effects of proprioceptive sense-based Kinesio taping on walking imbalance.

    PubMed

    Park, Young-Han; Lee, Jung-Ho

    2016-11-01

    [Purpose] The aim of this study was to determine how application of Kinesio tape to the upper and lower limbs affects walking through stimulation of the proprioceptive sense. [Subjects and Methods] Twelve patients diagnosed with hemiplegia due to stroke were selected as the subjects of the study. To ascertain the effects of Kinesio taping on walking, all subjects performed a straight line walking test three times while barefoot. In terms of the actual taping application, elastic Kinesio tape was used on the hemiplegic side in all subjects. [Results] The results of testing showed a significant difference in the values between before and after taping. In terms of left and right deviation according to the site of the taping application, there were statistically significant differences among the groups. [Conclusion] In conclusion, application of Kinesio taping for central nerve injury was confirmed to be effective in reducing walking deviation.

  9. Dynamic Visual Acuity While Walking in Normals and Labyrinthine-Deficient Patients

    NASA Technical Reports Server (NTRS)

    Hillman, Edward J.; Bloomberg, Jacob J.; McDonald, P. Vernon; Cohen, Helen S.

    1996-01-01

    We describe a new, objective, easily administered test of dynamic visual acuity (DVA) while walking. Ten normal subjects and five patients with histories of severe bilateral vestibular dysfunctions participated in this study. Subjects viewed a visual display of numerals of different font sizes presented on a laptop computer while they stood still and while they walked on a motorized treadmill. Treadmill speed was adapted for 4 of 5 patients. Subjects were asked to identify the numerals as they appeared on the computer screen. Test results were reasonably repeatable in normals. The percent correct responses at each font size dropped slightly while walking in normals and dropped significantly more in patients. Patients performed significantly worse than normals while standing still and while walking. This task may be useful for evaluating post-flight astronauts and vestibularly impaired patients.

  10. Efficient quantum walk on a quantum processor

    NASA Astrophysics Data System (ADS)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L.; Wang, Jingbo B.; Matthews, Jonathan C. F.

    2016-05-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  11. Learning to walk changes infants' social interactions.

    PubMed

    Clearfield, Melissa W

    2011-02-01

    The onset of crawling marks a motor, cognitive and social milestone. The present study investigated whether independent walking marks a second milestone for social behaviors. In Experiment 1, the social and exploratory behaviors of crawling infants were observed while crawling and in a baby-walker, resulting in no differences based on posture. In Experiment 2, the social behaviors of independently walking infants were compared to age-matched crawling infants in a baby-walker. Independently walking infants spent significantly more time interacting with the toys and with their mothers, and also made more vocalizations and more directed gestures compared to infants in the walker. Experiment 3 tracked infants' social behaviors longitudinally across the transition from crawling and walking. Even when controlled for age, the transition to independent walking marked increased interaction time with mothers, as well as more sophisticated interactions, including directing mothers' attention to particular objects. The results suggest a developmental progression linking social interactions with milestones in locomotor development.

  12. Efficient quantum walk on a quantum processor

    PubMed Central

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L.; Wang, Jingbo B.; Matthews, Jonathan C. F.

    2016-01-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor. PMID:27146471

  13. Go naked: diapers affect infant walking.

    PubMed

    Cole, Whitney G; Lingeman, Jesse M; Adolph, Karen E

    2012-11-01

    In light of cross-cultural and experimental research highlighting effects of childrearing practices on infant motor skill, we asked whether wearing diapers, a seemingly innocuous childrearing practice, affects infant walking. Diapers introduce bulk between the legs, potentially exacerbating infants' poor balance and wide stance. We show that walking is adversely affected by old-fashioned cloth diapers, and that even modern disposable diapers - habitually worn by most infants in the sample - incur a cost relative to walking naked. Infants displayed less mature gait patterns and more missteps and falls while wearing diapers. Thus, infants' own diapers constitute an ongoing biomechanical perturbation while learning to walk. Furthermore, shifts in diapering practices may have contributed to historical and cross-cultural differences in infant walking.

  14. Efficient quantum walk on a quantum processor.

    PubMed

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L; Wang, Jingbo B; Matthews, Jonathan C F

    2016-05-05

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  15. Neighbourhood walking and regeneration in deprived communities.

    PubMed

    Mason, Phil; Kearns, Ade; Bond, Lyndal

    2011-05-01

    More frequent neighbourhood walking is a realistic goal for improving physical activity in deprived areas. We address regeneration activity by examining associations of residents' circumstances and perceptions of their local environment with frequent (5+ days/week) local walking (NW5) in 32 deprived neighbourhoods (Glasgow, UK), based on interview responses from a random stratified cross-sectional sample of 5657 residents. Associations were investigated by bivariate and multilevel, multivariate logistic regression. People living in low-rise flats or houses reported greater NW5 than those in multi-storey flats. Physical and social aspects of the neighbourhood were more strongly related to walking than perceptions of housing and neighbourhood, especially the neighbourhood's external reputation, and feelings of safety and belonging. Amenity use, especially of parks, play areas and general shops (mainly in the neighbourhood), was associated with more walking. Multidimensional regeneration of the physical, service, social and psychosocial environments of deprived communities therefore seems an appropriate strategy to boost walking.

  16. DETERMINANTS OF USE OF A WALKING DEVICE IN PERSONS WITH PARKINSON’S DISEASE

    PubMed Central

    Bryant, Mon S; Rintala, Diana H; Graham, James E; Hou, Jyh-Gong; Protas, Elizabeth J

    2014-01-01

    Objective To identify determinants for use of a walking device in persons with Parkinson's disease (PD). Design Cross-sectional study of participants with PD. Setting Laboratory. Participants Eighty-five persons (60 Males) with PD were studied. Their mean age was 69.4 ± 8.9 years. The average time since diagnosis was 7.9 ± 5.3 years. Interventions Not applicable. Main Outcome Measures Age, gender, disease duration, disease severity and motor impairment were recorded. Participants were asked whether they usually used any walking device (e.g., cane or walker) and were categorized as either an “independent walker” or a “device walker.” Clinical balance measures including functional reach, turn duration, 5m Timed-Up-and-Go test (5m-TUG) and Activities-specific Balance Confidence (ABC) scale were investigated for their contribution to the prediction of walking with a device. Results Thirty-one participants (36.5%) reported they usually used a walking device. Classification and regression tree (CART) analysis determined that the 5m-TUG test and the ABC scale were important factors in differentiating participants who used a walking device from those who did not. Critical thresholds included 13 seconds for the 5m-TUG test and a score of 75 for the ABC scale in determining device walking. Using only those two determinants, the CART model correctly classified 81% of patients as either independent or needing a walking device. Conclusion The 5m-TUG test and ABC scale may be useful in clinical assessments of the need for a walking device in persons with PD. PMID:24953250

  17. Slope walking causes short-term changes in soleus H-reflex excitability

    PubMed Central

    Sabatier, Manning J; Wedewer, Wesley; Barton, Ben; Henderson, Eric; Murphy, John T; Ou, Kar

    2015-01-01

    The purpose of this study was to test the hypothesis that downslope treadmill walking decreases spinal excitability. Soleus H-reflexes were measured in sixteen adults on 3 days. Measurements were taken before and twice after 20 min of treadmill walking at 2.5 mph (starting at 10 and 45 min post). Participants walked on a different slope each day [level (Lv), upslope (Us) or downslope (Ds)]. The tibial nerve was electrically stimulated with a range of intensities to construct the M-response and H-reflex curves. Maximum evoked responses (Hmax and Mmax) and slopes of the ascending limbs (Hslp and Mslp) of the curves were evaluated. Rate-dependent depression (RDD) was measured as the % depression of the H-reflex when measured at a rate of 1.0 Hz versus 0.1 Hz. Heart rate (HR), blood pressure (BP), and ratings of perceived exertion (RPE) were measured during walking. Ds and Lv walking reduced the Hmax/Mmax ratio (P = 0.001 & P = 0.02), although the reduction was larger for Ds walking (29.3 ± 6.2% vs. 6.8 ± 5.2%, P = 0.02). The reduction associated with Ds walking was correlated with physical activity level as measured via questionnaire (r = −0.52, P = 0.04). Us walking caused an increase in the Hslp/Mslp ratio (P = 0.03) and a decrease in RDD (P = 0.04). These changes recovered by 45 min. Exercise HR and BP were highest during Us walking. RPE was greater during Ds and Us walking compared to Lv walking, but did not exceed “Fairly light” for Ds walking. In conclusion, in healthy adults treadmill walking has a short-term effect on soleus H-reflex excitability that is determined by the slope of the treadmill surface. PMID:25742955

  18. Walking speed estimation using a shank-mounted inertial measurement unit.

    PubMed

    Li, Q; Young, M; Naing, V; Donelan, J M

    2010-05-28

    We studied the feasibility of estimating walking speed using a shank-mounted inertial measurement unit. Our approach took advantage of the inverted pendulum-like behavior of the stance leg during walking to identify a new method for dividing up walking into individual stride cycles and estimating the initial conditions for the direct integration of the accelerometer and gyroscope signals. To test its accuracy, we compared speed estimates to known values during walking overground and on a treadmill. The speed estimation method worked well across treadmill speeds and slopes yielding a root mean square speed estimation error of only 7%. It also worked well during overground walking with a 4% error in the estimated travel distance. This accuracy is comparable to that achieved from foot-mounted sensors, providing an alternative in sensor positioning for walking speed estimation. Shank mounted sensors may be of great benefit for estimating speed in walking with abnormal foot motion and for the embedded control of knee-mounted devices such as prostheses and energy harvesters.

  19. Effect of treadmill walking with ankle stretching orthosis on ankle flexibility and gait

    PubMed Central

    Cho, Young-ki; Kim, Si-hyun; Jeon, In-cheol; Ahn, Sun-hee; Kwon, Oh-yun

    2015-01-01

    [Purpose] The purpose of this study was to evaluate the kinematics of the ankle in the lunge to estabilish effectiveness of an ankle stretching orthosis (ASO) on the ankle dorsiflexion range of motion (ROM) of individuals with limited dorsiflexion ROM. [Subjects and Methods] Forty ankles with decreased dorsiflexion ROM of 20 participants were evaluated in this study. After wearing the ASO, participants walked on a treadmill for 15 minutes. Participants walked on the treadmill at a self-selected comfortable speed. Ankle dorsiflexion ROM, maximum dorsiflexion ROM before heel-off, and time to heel-off during the stance phase of gait were measured before and after 15 minutes of treadmill walking with the ASO. The differences in all variables between before and after treadmill walking with ASO were analyzed using the paired t-test. [Results] Ankle active and passive ROM, and dorsiflexion ROM during lunge increased significantly after treadmill walking with ASO. Treadmill walking with the ASO significantly increased the angle of maximal dorsiflexion before heel-off and time to heel-off during the stance phase. [Conclusion] The results of this study show that treadmill walking with the ASO effectively improved ankle flexibility and restored the normal gait pattern of the ankle joint by increasing dorsiflexion ROM, maximal angle of dorsiflexion, and time to heel-off in the stance phase. PMID:25995601

  20. Medical Aspects of Space Walking

    NASA Technical Reports Server (NTRS)

    Musgrave, Story

    1999-01-01

    Dr. Musgrave has acquired extensive experience during a distinguished and impressive career that includes flying as an astronaut on six Shuttle missions, participating in many hours of extravehicular activity, and contributing his myriad talents toward great public service, especially in the area of education. He has a unique perspective as a physician, scientist, engineer, pilot, and scholar. His interests and breadth of knowledge, which astound even the seasoned space enthusiast, have provided the space program an extraordinary scientific and technical expertise. Dr. Musgrave presented a personal perspective on space flight with particular emphasis on extravehicular activity (EVA or space walking), which was copiously illustrated with photographs from many space missions. His theme was two fold: the exacting and detailed preparations required for successful execution of a mission plan and a cosmic view of mankind's place in the greater scheme of things.

  1. Snell's law and walking droplets

    NASA Astrophysics Data System (ADS)

    Bush, John; Pucci, Giuseppe; Aubin, Benjamin; Brun, Pierre-Thomas; Faria, Luiz

    2016-11-01

    Droplets walking on the surface of a vibrating bath have been shown to exhibit a number of quantum-like features. We here present the results of a combined experimental and theoretical investigation of such droplets crossing a linear step corresponding to a reduction in bath depth. When the step is sufficiently large, the walker reflects off the step; otherwise, it is refracted as it crosses the step. Particular attention is given to an examination of the regime in which the droplet obeys a form of Snell's Law, a behavior captured in accompanying simulations. Attempts to provide theoretical rationale for the dependence of the effective refractive index on the system parameters are described. Supported by NSF through CMMI-1333242.

  2. Physiological Cost Index and Comfort Walking Speed in Two Level Lower Limb Amputees Having No Vascular Disease

    PubMed Central

    Vllasolli, Teuta Osmani; Orovcanec, Nikola; Zafirova, Beti; Krasniqi, Blerim; Murtezani, Ardiana; Krasniqi, Valbona; Rama, Bukurije

    2015-01-01

    Background: The Physiological Cost Index (PCI) was introduced by MacGregor to estimate the energy cost in walking of healthy people, also it has been reported for persons with lower limb amputation, walking with prosthesis. Objective: To assess energy cost and walking speed in two level lower limb amputation: transfemoral and transtibial amputation and to determine if the age and prosthetic walking supported with walking aids have impact on energy cost and walking speed. Methods: A prospective cross sectional study was performed in two level lower limb amputees with no vascular disease who were rehabilitated at the Department of Prosthetics and Orthotics at the University Clinical Center of Kosovo. The Physiological Cost Index (PCI) was assessed by five minutes of continuous indoor walking at Comfort Walking Speed (CWS). Results: Eighty three lower limb amputees were recruited. It is shown relevant impact of level of amputation in PCI (t=6.8, p<0.001) and CWS (T=487, p<0.001). The great influence of using crutches during prosthetic walking in PCI (ANOVA F= 39.5 P < 0.001) and CWS (ANOVA F=32.01, P <0.001) has been shown by One Way ANOVA test. The correlation coefficient (R) showed a significant correlation of age with PCI and CWS in both groups of amputation. Conclusions: Walking with transfemoral prosthesis or using walking aids during prosthetic ambulation is matched with higher cost of energy and slower walking speed. Advanced age was shown with high impact on PCI and CWS in both groups of amputees. PMID:25870485

  3. 40 CFR 86.342-79 - Post-test procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Select the lowest HC range used during the test; (3) The difference between the span-zero response and..., or (b) Begin the analyzer span checks within 6 minutes after the completion of the last mode in the test. Record for each analyzer the zero and span response for each range used during the preceding...

  4. 40 CFR 86.342-79 - Post-test procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Select the lowest HC range used during the test; (3) The difference between the span-zero response and..., or (b) Begin the analyzer span checks within 6 minutes after the completion of the last mode in the test. Record for each analyzer the zero and span response for each range used during the preceding...

  5. The effect of walking on cardiorespiratory fitness in adults with knee osteoarthritis.

    PubMed

    Larose, Joanie; King, Judy; Brosseau, Lucie; Wells, George A; Reid, Robert; Maetzel, Andreas; Tugwell, Peter; Huijbregts, Maria; McCullough, Carolyn; Loew, Laurianne; Kenny, Glen P

    2013-08-01

    Walking programs alone or in combination with behavioral interventions have proven effective at improving quality of life among older adults with osteoarthritis (OA). It is unclear, however, whether the combination of both of these treatments is more effective at improving cardiorespiratory fitness in older adults with knee OA than a walking program alone or than unsupervised self-directed walking. In this study, we assessed cardiorespiratory fitness with 3 programs: a structured supervised community-based aerobic walking program with a behavioral intervention (WB; n = 41); a supervised program of walking only (W; n = 42); and an unsupervised self-directed walking program (n = 32). We measured maximal oxygen uptake (V̇O2peak), exercise test duration, and workload, heart rate, and ventilation at maximum aerobic capacity in older adults with knee OA after 6 months of WB, W, or self-directed walking. Overall, V̇O2peak improved by 4% in female walkers (+0.9 ± 2.5 mL O2·kg(-1)·min(-1); p < 0.001) and 5% in male walkers (+1.3 ± 2.7 mL O2·kg(-1)·min(-1); p < 0.001), and the change in fitness was similar with all 3 walking interventions. In conclusion, low- to moderate-intensity walking may improve and (or) prevent decrements in cardiorespiratory fitness in older adults with OA. This response was comparable in supervised walkers with and without a behavioral intervention and in unsupervised self-directed walkers.

  6. Check the score: Field validation of Street Smart Walk Score in Alberta, Canada.

    PubMed

    Nykiforuk, Candace I J; McGetrick, Jennifer Ann; Crick, Katelynn; Johnson, Jeffrey A

    2016-12-01

    Walk Score® is a proprietary walkability metric that ranks locations by proximity to destinations, with emerging health promotion applications for increasing walking as physical activity. Currently, field validations of Walk Score® have only occurred in metropolitan regions of the United States; moreover, many studies employ an earlier Walk Score® version utilizing straight line distance. To address this gap, we conducted a field validation of the newest, network-based metric for three municipal types along a rural-urban continuum in Alberta, Canada. In 2015, using street-level systematic observations collected in Bonnyville, Medicine Hat, and North Central Edmonton in 2008 (part of the Community Health and the Built Environment (CHBE) project), we reverse engineered 2181 scores with the network Walk Score® algorithm. We computed means, 95% confidence intervals, and t-tests (α = 0.05) for both sets of scores. Applying the Clifford-Richardson adjustment for spatial autocorrelation, we calculated Spearman's Rank Correlation Coefficients (rho, rs) and adjusted p-values to measure the strength of association between the derived scores and original network scores provided by Walk Score®. Spearman's rho for scores were very high for Bonnyville (rs = 0.950, adjusted p < 0.001), and high for Medicine Hat (rs = 0.790, adjusted p < 0.001) and North Central Edmonton (rs = 0.763, adjusted p < 0.001). High to very high correlations between derived scores and Walk Scores® field validated this metric across small, medium, and large population centres in Alberta, Canada. However, we suggest caution in interpreting Walk Score® for planning and evaluating health promotion interventions, since the strength of association between destinations and walking may vary across different municipal types.

  7. Built Environment Correlates of Walking: A Review

    PubMed Central

    Saelens, Brian E.; Handy, Susan L.

    2010-01-01

    Introduction The past decade has seen a dramatic increase in the empirical investigation into the relations between built environmental and physical activity. To create places that facilitate and encourage walking, practitioners need an understanding of the specific characteristics of the built environment that correlate most strongly with walking. This paper reviews evidence on the built environment correlates with walking. Method Included in this review were 13 reviews published between 2002 and 2006 and 29 original studies published in 2005 and up through May 2006. Results were summarized based on specific characteristics of the built environment and transportation walking versus recreational walking. Results Previous reviews and newer studies document consistent positive relations between walking for transportation and density, distance to non-residential destinations, and land use mix; findings for route/network connectivity, parks and open space, and personal safety are more equivocal. Results regarding recreational walking were less clear. Conclusions More recent evidence supports the conclusions of prior reviews, and new studies address some of the limitations of earlier studies. Although prospective studies are needed, evidence on correlates appears sufficient to support policy changes. PMID:18562973

  8. Factors Influencing Whether Children Walk to School

    PubMed Central

    Su, Jason G.; Jerrett, Michael; Mcconnell, Rob; Berhane, Kiros; Dunton, Genevieve; Shankardass, Ketan; Reynolds, Kim; Chang, Roger; Wolch, Jennifer

    2015-01-01

    Few studies have evaluated multiple levels of influence simultaneously on whether children walk to school. A large cohort of 4,338 subjects from ten communities was used to identify the determinants of walking through (1) a one-level logistic regression model for individual-level variables and (2) a two-level mixed regression model for individual and school-level variables. Walking rates were positively associated with home-to-school proximity, greater age, and living in neighborhoods characterized by lower traffic density. Greater land use mix around the home was, however, associated with lower rates of walking. Rates of walking to school were also higher amongst recipients of the Free and Reduced Price Meals Program and attendees of schools with higher percentage of English language learners. Designing schools in the same neighborhood as residential districts should be an essential urban planning strategy to reduce walking distance to school. Policy interventions are needed to encourage children from higher socioeconomic status families to participate in active travel to school and to develop walking infrastructures and other measures that protect disadvantaged children. PMID:23707968

  9. Statistical Modeling of Robotic Random Walks on Different Terrain

    NASA Astrophysics Data System (ADS)

    Naylor, Austin; Kinnaman, Laura

    Issues of public safety, especially with crowd dynamics and pedestrian movement, have been modeled by physicists using methods from statistical mechanics over the last few years. Complex decision making of humans moving on different terrains can be modeled using random walks (RW) and correlated random walks (CRW). The effect of different terrains, such as a constant increasing slope, on RW and CRW was explored. LEGO robots were programmed to make RW and CRW with uniform step sizes. Level ground tests demonstrated that the robots had the expected step size distribution and correlation angles (for CRW). The mean square displacement was calculated for each RW and CRW on different terrains and matched expected trends. The step size distribution was determined to change based on the terrain; theoretical predictions for the step size distribution were made for various simple terrains. It's Dr. Laura Kinnaman, not sure where to put the Prefix.

  10. How important is the land use mix measure in understanding walking behaviour? Results from the RESIDE study

    PubMed Central

    2011-01-01

    Background Understanding the relationship between urban design and physical activity is a high priority. Different representations of land use diversity may impact the association between neighbourhood design and specific walking behaviours. This study examined different entropy based computations of land use mix (LUM) used in the development of walkability indices (WIs) and their association with walking behaviour. Methods Participants in the RESIDential Environments project (RESIDE) self-reported mins/week of recreational, transport and total walking using the Neighbourhood Physical Activity Questionnaire (n = 1798). Land use categories were incrementally added to test five different LUM models to identify the strongest associations with recreational, transport and total walking. Logistic regression was used to analyse associations between WIs and walking behaviour using three cut points: any (> 0 mins), ≥ 60 mins and ≥ 150 mins walking/week. Results Participants in high (vs. low) walkable neighbourhoods reported up to almost twice the amount of walking, irrespective of the LUM measure used. However, different computations of LUM were found to be relevant for different types and amounts of walking (i.e., > 0, ≥ 60 or ≥ 150 mins/week). Transport walking (≥ 60 mins/week) had the strongest and most significant association (OR = 2.24; 95% CI:1.58-3.18) with the WI when the LUM included 'residential', 'retail', 'office', 'health, welfare and community', and 'entertainment, culture and recreation'. However, any (> 0 mins/week) recreational walking was more strongly associated with the WI (OR = 1.36; 95% CI:1.04-1.78) when land use categories included 'public open space', 'sporting infrastructure' and 'primary and rural' land uses. The observed associations were generally stronger for ≥ 60 mins/week compared with > 0 mins/week of transport walking and total walking but this relationship was not seen for recreational walking. Conclusions Varying the

  11. Quantum Walk Schemes for Universal Quantum Computation

    NASA Astrophysics Data System (ADS)

    Underwood, Michael S.

    Random walks are a powerful tool for the efficient implementation of algorithms in classical computation. Their quantum-mechanical analogues, called quantum walks, hold similar promise. Quantum walks provide a model of quantum computation that has recently been shown to be equivalent in power to the standard circuit model. As in the classical case, quantum walks take place on graphs and can undergo discrete or continuous evolution, though quantum evolution is unitary and therefore deterministic until a measurement is made. This thesis considers the usefulness of continuous-time quantum walks to quantum computation from the perspectives of both their fundamental power under various formulations, and their applicability in practical experiments. In one extant scheme, logical gates are effected by scattering processes. The results of an exhaustive search for single-qubit operations in this model are presented. It is shown that the number of distinct operations increases exponentially with the number of vertices in the scattering graph. A catalogue of all graphs on up to nine vertices that implement single-qubit unitaries at a specific set of momenta is included in an appendix. I develop a novel scheme for universal quantum computation called the discontinuous quantum walk, in which a continuous-time quantum walker takes discrete steps of evolution via perfect quantum state transfer through small 'widget' graphs. The discontinuous quantum-walk scheme requires an exponentially sized graph, as do prior discrete and continuous schemes. To eliminate the inefficient vertex resource requirement, a computation scheme based on multiple discontinuous walkers is presented. In this model, n interacting walkers inhabiting a graph with 2n vertices can implement an arbitrary quantum computation on an input of length n, an exponential savings over previous universal quantum walk schemes. This is the first quantum walk scheme that allows for the application of quantum error correction

  12. Quantum walk public-key cryptographic system

    NASA Astrophysics Data System (ADS)

    Vlachou, C.; Rodrigues, J.; Mateus, P.; Paunković, N.; Souto, A.

    2015-12-01

    Quantum Cryptography is a rapidly developing field of research that benefits from the properties of Quantum Mechanics in performing cryptographic tasks. Quantum walks are a powerful model for quantum computation and very promising for quantum information processing. In this paper, we present a quantum public-key cryptographic system based on quantum walks. In particular, in the proposed protocol the public-key is given by a quantum state generated by performing a quantum walk. We show that the protocol is secure and analyze the complexity of public key generation and encryption/decryption procedures.

  13. [Walking assist robot and its clinical application].

    PubMed

    Kakou, Hiroaki; Shitama, Hideo; Kimura, Yoshiko; Nakamoto, Yoko; Furuta, Nami; Honda, Kanae; Wada, Futoshi; Hachisuka, Kenji

    2009-06-01

    The walking assist robot was developed to improve gait disturbance in patients with severe disabilities. The robot had a trunk supporter, power generator and operating arms which held patient's lower extremities and simulated walking, a control unit, biofeedback system, and a treadmill. We applied the robot-aided gait training to three patients with severe gait disturbance induced by stroke, axonal Guillan-Barré syndrome or spinal cord injury, and the walking assist robot turned out to be effective in improving the gait disturbance.

  14. Machines that walk: The adaptive suspension vehicle

    NASA Astrophysics Data System (ADS)

    Song, Shin-Min; Waldron, Kenneth J.

    The design and operation of statically stable fully terrain-adaptive walking machines are discussed, with an emphasis on the adaptive-suspension vehicle developed at Ohio State University (Waldron and McGhee, 1986). Chapters are devoted to a review of walking-machine development, gait analysis and gaits for level walking, gaits for irregular terrain, coordination, leg design by four-bar linkage synthesis, design of a pantograph leg, motion-controlled ankle design, and the Adaptive Suspension Vehicle. Diagrams, drawings, and graphs are provided.

  15. Random walks on simplicial complexes and harmonics†

    PubMed Central

    Steenbergen, John

    2016-01-01

    Abstract In this paper, we introduce a class of random walks with absorbing states on simplicial complexes. Given a simplicial complex of dimension d, a random walk with an absorbing state is defined which relates to the spectrum of the k‐dimensional Laplacian for 1 ≤ k ≤ d. We study an example of random walks on simplicial complexes in the context of a semi‐supervised learning problem. Specifically, we consider a label propagation algorithm on oriented edges, which applies to a generalization of the partially labelled classification problem on graphs. © 2016 Wiley Periodicals, Inc. Random Struct. Alg., 49, 379–405, 2016

  16. Sensor-based hip control with hybrid neuroprosthesis for walking in paraplegia.

    PubMed

    To, Curtis S; Kobetic, Rudi; Bulea, Thomas C; Audu, Musa L; Schnellenberger, John R; Pinault, Gilles; Triolo, Ronald J

    2014-01-01

    The objectives of this study were to test whether a hybrid neuroprosthesis (HNP) with an exoskeletal variable-constraint hip mechanism (VCHM) combined with a functional neuromuscular stimulation (FNS) controller can maintain upright posture with less upper-limb support and improve gait speed as compared with walking with either an isocentric reciprocating gait orthosis (IRGO) or FNS only. The results show that walking with the HNP significantly reduced forward lean in FNS-only walking and the maximum upper-limb forces by 42% and 19% as compared with the IRGO and FNS-only gait, respectively. Walking speed increased significantly with VCHM as compared with 1:1 reciprocal coupling and by 15% when using the sensor-based FNS controller as compared with HNP with fixed baseline stimulation without the controller active.

  17. High Point Walking for Health: Creating Built and Social Environments That Support Walking in a Public Housing Community

    PubMed Central

    Rabkin, Janice; Sharify, Denise; Song, Lin

    2009-01-01

    Objectives. We implemented and evaluated multiple interventions to increase walking activity at a multicultural public housing site. Methods. A community-based participatory research partnership and community action teams assessed assets and barriers related to walking and developed multiple interventions to promote walking activity. Interventions included sponsoring walking groups, improving walking routes, providing information about walking options, and advocating for pedestrian safety. A pre–post study design was used to assess the changes in walking activity. Results. Self-reported walking activity increased among walking group participants from 65 to 109 minutes per day (P = .001). The proportion that reported being at least moderately active for at least 150 minutes per week increased from 62% to 81% (P = .018). Conclusions. A multicomponent intervention developed through participatory research methods that emphasized walking groups and included additional strategies to change the built and social environments increased walking activity at a public housing site in Seattle. PMID:19890163

  18. A New Method of Random Environmental Walking for Assessing Behavioral Preferences for Different Lighting Applications

    PubMed Central

    Patching, Geoffrey R.; Rahm, Johan; Jansson, Märit; Johansson, Maria

    2017-01-01

    Accurate assessment of people’s preferences for different outdoor lighting applications is increasingly considered important in the development of new urban environments. Here a new method of random environmental walking is proposed to complement current methods of assessing urban lighting applications, such as self-report questionnaires. The procedure involves participants repeatedly walking between different lighting applications by random selection of a lighting application and preferred choice or by random selection of a lighting application alone. In this manner, participants are exposed to all lighting applications of interest more than once and participants’ preferences for the different lighting applications are reflected in the number of times they walk to each lighting application. On the basis of an initial simulation study, to explore the feasibility of this approach, a comprehensive field test was undertaken. The field test included random environmental walking and collection of participants’ subjective ratings of perceived pleasantness (PP), perceived quality, perceived strength, and perceived flicker of four lighting applications. The results indicate that random environmental walking can reveal participants’ preferences for different lighting applications that, in the present study, conformed to participants’ ratings of PP and perceived quality of the lighting applications. As a complement to subjectively stated environmental preferences, random environmental walking has the potential to expose behavioral preferences for different lighting applications. PMID:28337163

  19. A New Method of Random Environmental Walking for Assessing Behavioral Preferences for Different Lighting Applications.

    PubMed

    Patching, Geoffrey R; Rahm, Johan; Jansson, Märit; Johansson, Maria

    2017-01-01

    Accurate assessment of people's preferences for different outdoor lighting applications is increasingly considered important in the development of new urban environments. Here a new method of random environmental walking is proposed to complement current methods of assessing urban lighting applications, such as self-report questionnaires. The procedure involves participants repeatedly walking between different lighting applications by random selection of a lighting application and preferred choice or by random selection of a lighting application alone. In this manner, participants are exposed to all lighting applications of interest more than once and participants' preferences for the different lighting applications are reflected in the number of times they walk to each lighting application. On the basis of an initial simulation study, to explore the feasibility of this approach, a comprehensive field test was undertaken. The field test included random environmental walking and collection of participants' subjective ratings of perceived pleasantness (PP), perceived quality, perceived strength, and perceived flicker of four lighting applications. The results indicate that random environmental walking can reveal participants' preferences for different lighting applications that, in the present study, conformed to participants' ratings of PP and perceived quality of the lighting applications. As a complement to subjectively stated environmental preferences, random environmental walking has the potential to expose behavioral preferences for different lighting applications.

  20. Effect of walking speed on lower extremity joint loading in graded ramp walking.

    PubMed

    Schwameder, Hermann; Lindenhofer, Elke; Müller, Erich

    2005-07-01

    Lower extremity joint loading during walking is strongly affected by the steepness of the slope and might cause pain and injuries in lower extremity joint structures. One feasible measure to reduce joint loading is the reduction of walking speed. Positive effects have been shown for level walking, but not for graded walking or hiking conditions. The aim of the study was to quantify the effect of walking speed (separated into the two components, step length and cadence) on the joint power of the hip, knee and ankle and to determine the knee joint forces in uphill and downhill walking. Ten participants walked up and down a ramp with step lengths of 0.46, 0.575 and 0.69 m and cadences of 80, 100 and 120 steps per minute. The ramp was equipped with a force platform and the locomotion was filmed with a 60 Hz video camera. Loading of the lower extremity joints was determined using inverse dynamics. A two-dimensional knee model was used to calculate forces in the knee structures during the stance phase. Walking speed affected lower extremity joint loading substantially and significantly. Change of step length caused much greater loading changes for all joints compared with change of cadence; the effects were more distinct in downhill than in uphill walking. The results indicate that lower extremity joint loading can be effectively controlled by varying step length and cadence during graded uphill and downhill walking. Hikers can avoid or reduce pain and injuries by reducing walking speed, particularly in downhill walking.

  1. Urban Walking and the Pedagogies of the Street

    ERIC Educational Resources Information Center

    Bairner, Alan

    2011-01-01

    Drawing upon the extensive literature on urban walking and also on almost 60 years' experience of walking the streets, this article argues that there is a pressing need to re-assert the educational value of going for a walk. After a brief discussion of the social significance of the "flaneur," the historic pioneer of urban walking, the article…

  2. Nordic Walking Practice Might Improve Plantar Pressure Distribution

    ERIC Educational Resources Information Center

    Perez-Soriano, Pedro; Llana-Belloch, Salvador; Martinez-Nova, Alfonso; Morey-Klapsing, G.; Encarnacion-Martinez, Alberto

    2011-01-01

    Nordic walking (NW), characterized by the use of two walking poles, is becoming increasingly popular (Morgulec-Adamowicz, Marszalek, & Jagustyn, 2011). We studied walking pressure patterns of 20 experienced and 30 beginner Nordic walkers. Plantar pressures from nine foot zones were measured during trials performed at two walking speeds (preferred…

  3. Walking and Eating Behavior of Toddlers at 12 Months Old

    ERIC Educational Resources Information Center

    Koda, Naoko; Akimoto, Yuko; Hirose, Toshiya; Hinobayashi, Toshihiko; Minami, Tetsuhiro

    2004-01-01

    Locomotive and eating behavior of 52 toddlers was observed at 12 months old in a nursery school and investigated in relation to the acquisition of independent walking. The toddlers who acquired walking ate more by themselves using the hands than the toddlers who did not start walking. This suggested that acquisition of walking was associated with…

  4. Walking after Stroke: Comfortable versus Maximum Safe Speed.

    ERIC Educational Resources Information Center

    Bohannon, Richard W.

    1992-01-01

    This study attempted to (1) determine whether stroke patients (n=20) can safely increase their walking speed above that of comfortable walking; (2) describe the relationship between comfortable and maximum safe walking speed; and (3) examine correlations between maximum and comfortable speeds and a functional walking score. Subjects were able to…

  5. Minimal walking technicolor: Setup for collider physics

    SciTech Connect

    Foadi, Roshan; Frandsen, Mads T.; Ryttov, Thomas A.; Sannino, Francesco

    2007-09-01

    Different theoretical and phenomenological aspects of the minimal and nonminimal walking technicolor theories have recently been studied. The goal here is to make the models ready for collider phenomenology. We do this by constructing the low energy effective theory containing scalars, pseudoscalars, vector mesons, and other fields predicted by the minimal walking theory. We construct their self-interactions and interactions with standard model fields. Using the Weinberg sum rules, opportunely modified to take into account the walking behavior of the underlying gauge theory, we find interesting relations for the spin-one spectrum. We derive the electroweak parameters using the newly constructed effective theory and compare the results with the underlying gauge theory. Our analysis is sufficiently general such that the resulting model can be used to represent a generic walking technicolor theory not at odds with precision data.

  6. Community walking in people with Parkinson's disease.

    PubMed

    Lamont, Robyn M; Morris, Meg E; Woollacott, Marjorie H; Brauer, Sandra G

    2012-01-01

    People with Parkinson's disease often have walking difficulty, and this is likely to be exacerbated while walking in places in the community, where people are likely to face greater and more varied challenges. This study aims to understand the facilitators and the barriers to walking in the community perceived by people with Parkinson's disease. This qualitative study involved 5 focus groups (n = 34) of people with Parkinson's disease and their partners residing in metropolitan and rural regions in Queensland, Australia. Results found that people with PD reported to use internal personal strategies as facilitators to community walking, but identified primarily external factors, particularly the environmental factors as barriers. The adoption of strategies or the use of facilitators allows people with Parkinson's disease to cope so that participants often did not report disability.

  7. Epidemic spreading driven by biased random walks

    NASA Astrophysics Data System (ADS)

    Pu, Cunlai; Li, Siyuan; Yang, Jian

    2015-08-01

    Random walk is one of the basic mechanisms of many network-related applications. In this paper, we study the dynamics of epidemic spreading driven by biased random walks in complex networks. In our epidemic model, infected nodes send out infection packets by biased random walks to their neighbor nodes, and this causes the infection of susceptible nodes that receive the packets. Infected nodes recover from the infection at a constant rate λ, and will not be infected again after recovery. We obtain the largest instantaneous number of infected nodes and the largest number of ever-infected nodes respectively, by tuning the parameter α of the biased random walks. Simulation results on model and real-world networks show that spread of the epidemic becomes intense and widespread with increase of either delivery capacity of infected nodes, average node degree, or homogeneity of node degree distribution.

  8. Walking with coffee: why does it spill?

    PubMed

    Mayer, H C; Krechetnikov, R

    2012-04-01

    In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.

  9. Walking with coffee: Why does it spill?

    NASA Astrophysics Data System (ADS)

    Mayer, H. C.; Krechetnikov, R.

    2012-04-01

    In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.

  10. Database of Standardized Questionnaires About Walking & Bicycling

    Cancer.gov

    This database contains questionnaire items and a list of validation studies for standardized items related to walking and biking. The items come from multiple national and international physical activity questionnaires.

  11. Design of a walking robot

    NASA Astrophysics Data System (ADS)

    Whittaker, William; Dowling, Kevin

    1994-03-01

    Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.

  12. Holographic walking from tachyon DBI

    NASA Astrophysics Data System (ADS)

    Kutasov, David; Lin, Jennifer; Parnachev, Andrei

    2012-10-01

    We use holography to study conformal phase transitions, which are believed to be realized in four dimensional QCD and play an important role in walking technicolor models of electroweak symmetry breaking. At strong coupling they can be modeled by the non-linear dynamics of a tachyonic scalar field with mass close to the Breitenlohner-Freedman bound in anti-de Sitter spacetime. Taking the action for this field to have a tachyon-Dirac-Born-Infeld form gives rise to models that resemble hard and soft wall AdS/QCD, with a dynamically generated wall. For hard wall models, the highly excited spectrum has the KK form mn˜n; in the soft wall case we exhibit potentials with mn˜nα, 0<α⩽1/2. We investigate the finite temperature phase structure and find first or second order symmetry restoration transitions, depending on the behavior of the potential near the origin of field space.

  13. Adaptive walking in Alzheimer's disease.

    PubMed

    Orcioli-Silva, Diego; Simieli, Lucas; Barbieri, Fabio Augusto; Stella, Florindo; Gobbi, Lilian Teresa Bucken

    2012-01-01

    The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients.

  14. Adaptive Walking in Alzheimer's Disease

    PubMed Central

    Orcioli-Silva, Diego; Simieli, Lucas; Barbieri, Fabio Augusto; Stella, Florindo; Gobbi, Lilian Teresa Bucken

    2012-01-01

    The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients. PMID:22991684

  15. Design of a walking robot

    NASA Technical Reports Server (NTRS)

    Whittaker, William; Dowling, Kevin

    1994-01-01

    Carnegie Mellon University's Autonomous Planetary Exploration Program (APEX) is currently building the Daedalus robot; a system capable of performing extended autonomous planetary exploration missions. Extended autonomy is an important capability because the continued exploration of the Moon, Mars and other solid bodies within the solar system will probably be carried out by autonomous robotic systems. There are a number of reasons for this - the most important of which are the high cost of placing a man in space, the high risk associated with human exploration and communication delays that make teleoperation infeasible. The Daedalus robot represents an evolutionary approach to robot mechanism design and software system architecture. Daedalus incorporates key features from a number of predecessor systems. Using previously proven technologies, the Apex project endeavors to encompass all of the capabilities necessary for robust planetary exploration. The Ambler, a six-legged walking machine was developed by CMU for demonstration of technologies required for planetary exploration. In its five years of life, the Ambler project brought major breakthroughs in various areas of robotic technology. Significant progress was made in: mechanism and control, by introducing a novel gait pattern (circulating gait) and use of orthogonal legs; perception, by developing sophisticated algorithms for map building; and planning, by developing and implementing the Task Control Architecture to coordinate tasks and control complex system functions. The APEX project is the successor of the Ambler project.

  16. "I'm Just a'-Walking the Dog" correlates of regular dog walking.

    PubMed

    Christian nee Cutt, Hayley; Giles-Corti, Billie; Knuiman, Matthew

    2010-01-01

    Intrapersonal and environmental factors associated with dog walking (N = 483) were examined. A greater proportion of regular (80%) than irregular (59%) dog walkers met the recommended 150 minutes of physical activity per week. Owners who perceived greater social support and motivation from their dogs to walk, and who had access to a dog-supportive park within their neighborhood, were more likely to regularly walk with their dogs, even after adjustment for other well-known correlates of physical activity. The higher level of physical activity of regular dog walkers can be attributed to the additional walking these owners perform with their dogs.

  17. Biomechanical implications of walking with indigenous footwear

    PubMed Central

    Willems, Catherine; Stassijns, Gaetane; Cornelis, Wim; D'Août, Kristiaan

    2017-01-01

    Abstract Objectives This study investigates biomechanical implications of walking with indigenous “Kolhapuri” footwear compared to barefoot walking among a population of South Indians. Materials and methods Ten healthy adults from South India walked barefoot and indigenously shod at voluntary speed on an artificial substrate. The experiment was repeated outside, on a natural substrate. Data were collected from (1) a heel‐mounted 3D‐accelerometer recording peak impact at heel contact, (2) an ankle‐mounted 3D‐goniometer (plantar/dorsiflexion and inversion/eversion), and (3) sEMG electrodes at the m. tibialis anterior and the m. gastrocnemius medialis. Results Data show that the effect of indigenous footwear on the measured variables, compared to barefoot walking, is relatively small and consistent between substrates (even though subjects walked faster on the natural substrate). Walking barefoot, compared to shod walking yields higher impact accelerations, but the differences are small and only significant for the artificial substrate. The main rotations of the ankle joint are mostly similar between conditions. Only the shod condition shows a faster ankle rotation over the rapid eversion motion on the natural substrate. Maximal dorsiflexion in late stance differs between the footwear conditions on an artificial substrate, with the shod condition involving a less dorsiflexed ankle, and the plantar flexion at toe‐off is more extreme when shod. Overall the activity pattern of the external foot muscles is similar. Discussion The indigenous footwear studied (Kolhapuri) seems to alter foot biomechanics only in a subtle way. While offering some degree of protection, walking in this type of footwear resembles barefoot gait and this type of indigenous footwear might be considered “minimal”. PMID:28101944

  18. Mesonic spectroscopy of minimal walking technicolor

    SciTech Connect

    Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino; Pica, Claudio; Rago, Antonio

    2010-07-01

    We investigate the structure and the novel emerging features of the mesonic nonsinglet spectrum of the minimal walking technicolor theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD-like theory. Our results favor a scenario in which minimal walking technicolor is (almost) conformal in the infrared, while spontaneous chiral symmetry breaking seems less plausible.

  19. Iron deficiency and physical growth predict attainment of walking but not crawling in poorly nourished Zanzibari infants.

    PubMed

    Kariger, Patricia K; Stoltzfus, Rebecca J; Olney, Deanna; Sazawal, Sunil; Black, Robert; Tielsch, James M; Frongillo, Edward A; Khalfan, Sabra S; Pollitt, Ernesto

    2005-04-01

    Locomotion allows infants to explore their environment, promoting development in other domains. Motor progression involves biological systems and experiential factors. Nutritional deficiencies could interfere with systems involved in locomotion. This study examined the associations between height-for-age (HAZ), weight-for-height (WHZ) Z-scores and anemia-iron status on locomotion in 646 Zanzibari infants. Motor milestones were assessed by trained observers using a 14-item scale. Two mutually exclusive samples were created. The crawling sample (n = 167, 6-18 mo old) included infants that crawled only or did not crawl; the walking sample (n = 479, 9-18 mo old) included children that walked alone or did not walk alone. Of the crawling and walking samples, 82.6 and 83.9% respectively, were iron deficient and/or anemic (hemoglobin < 100 g/L; zinc protoporphyrin > or = 90 micromol/mol heme). Stunting (HAZ less than -2) occurred in 30.5% of the crawling sample and 38.4% of the walking sample. Logistic regression models estimated the influence of factors on crawling vs. not crawling or walking vs. not walking. Two models were tested: 1) included sex, age, SES, HAZ and WHZ; 2) added anemia-iron status category to Model 1. HAZ improved the odds of crawling by 30%, but was not significant in either model. Model 2 fit the walking sample data best (P < 0.0001); an increase in HAZ doubled the odds of walking and nonanemic, noniron deficient children were 66% more likely to walk than those with anemia and/or iron deficiency. In this sample of poorly nourished infants, growth and anemia-iron status are significant predictors of walking, but not crawling.

  20. Reconstructing the behavior of walking fruit flies

    NASA Astrophysics Data System (ADS)

    Berman, Gordon; Bialek, William; Shaevitz, Joshua

    2010-03-01

    Over the past century, the fruit fly Drosophila melanogaster has arisen as almost a lingua franca in the study of animal behavior, having been utilized to study questions in fields as diverse as sleep deprivation, aging, and drug abuse, amongst many others. Accordingly, much is known about what can be done to manipulate these organisms genetically, behaviorally, and physiologically. Most of the behavioral work on this system to this point has been experiments where the flies in question have been given a choice between some discrete set of pre-defined behaviors. Our aim, however, is simply to spend some time with a cadre of flies, using techniques from nonlinear dynamics, statistical physics, and machine learning in an attempt to reconstruct and gain understanding into their behavior. More specifically, we use a multi-camera set-up combined with a motion tracking stage in order to obtain long time-series of walking fruit flies moving about a glass plate. This experimental system serves as a test-bed for analytical, statistical, and computational techniques for studying animal behavior. In particular, we attempt to reconstruct the natural modes of behavior for a fruit fly through a data-driven approach in a manner inspired by recent work in C. elegans and cockroaches.

  1. Visual estimation of travel distance during walking.

    PubMed

    Lappe, Markus; Frenz, Harald

    2009-12-01

    The optic flow generated in the eyes during self-motion provides an important control signal for direction and speed of self-motion, and can be used to track the distance that has been traveled. The use of vision for these behavioral tasks can be studied in isolation in virtual reality setups, in which self-motion is merely simulated, and in which the visual motion can be controlled independently of other sensory cues. In such experiments it was found that the estimation of the travel distance of a simulated movement shows characteristic errors, sometimes overestimating and sometimes underestimating the true travel distance. These errors can be explained by a leaky path integration model. To test whether this model also holds for actual self-motion in the real world we studied walking distance perception in an open field with tasks similar to those previously used in virtual environments. We show that similar errors occur in the estimation of travel distance in the real world as in virtual environment, and that they are consistent with the leaky integration model.

  2. Calcaneal loading during walking and running

    NASA Technical Reports Server (NTRS)

    Giddings, V. L.; Beaupre, G. S.; Whalen, R. T.; Carter, D. R.

    2000-01-01

    PURPOSE: This study of the foot uses experimentally measured kinematic and kinetic data with a numerical model to evaluate in vivo calcaneal stresses during walking and running. METHODS: External ground reaction forces (GRF) and kinematic data were measured during walking and running using cineradiography and force plate measurements. A contact-coupled finite element model of the foot was developed to assess the forces acting on the calcaneus during gait. RESULTS: We found that the calculated force-time profiles of the joint contact, ligament, and Achilles tendon forces varied with the time-history curve of the moment about the ankle joint. The model predicted peak talocalcaneal and calcaneocuboid joint loads of 5.4 and 4.2 body weights (BW) during walking and 11.1 and 7.9 BW during running. The maximum predicted Achilles tendon forces were 3.9 and 7.7 BW for walking and running. CONCLUSIONS: Large magnitude forces and calcaneal stresses are generated late in the stance phase, with maximum loads occurring at approximately 70% of the stance phase during walking and at approximately 60% of the stance phase during running, for the gait velocities analyzed. The trajectories of the principal stresses, during both walking and running, corresponded to each other and qualitatively to the calcaneal trabecular architecture.

  3. Goals and Social Comparisons Promote Walking Behavior.

    PubMed

    Chapman, Gretchen B; Colby, Helen; Convery, Kimberly; Coups, Elliot J

    2016-05-01

    The effectiveness of a pedometer intervention was affected by manipulating the goals given to participants and by providing social comparison feedback about how participants' performance compared with others. In study 1 (n= 148), university staff members received a low, medium, or high walking goal (10%, 50%, or 100% increase over baseline walking). Participants walked 1358 more steps per day (95% confidence interval [CI], 729, 1985), when receiving a high goal than when receiving a medium goal, but a medium goal did not increase walking relative to a low goal (554 more steps; 95% CI, -71,1179). In study 2 (n= 64), participants received individual feedback only or individual plus social comparison feedback. Participants walked 1120 more steps per day (95% CI, 538, 1703) when receiving social comparison feedback than when receiving only individual feedback. Goals and the performance of others act as reference points and influence the effect that pedometer feedback has on walking behavior, illustrating the applicability of the principles of behavioral economics and social psychology to the design of health behavior interventions.

  4. Developmental continuity? Crawling, cruising, and walking.

    PubMed

    Adolph, Karen E; Berger, Sarah E; Leo, Andrew J

    2011-03-01

    This research examined developmental continuity between "cruising" (moving sideways holding onto furniture for support) and walking. Because cruising and walking involve locomotion in an upright posture, researchers have assumed that cruising is functionally related to walking. Study 1 showed that most infants crawl and cruise concurrently prior to walking, amassing several weeks of experience with both skills. Study 2 showed that cruising infants perceive affordances for locomotion over an adjustable gap in a handrail used for manual support, but despite weeks of cruising experience, cruisers are largely oblivious to the dangers of gaps in the floor beneath their feet. Study 3 replicated the floor-gap findings for infants taking their first independent walking steps, and showed that new walkers also misperceive affordances for locomoting between gaps in a handrail. The findings suggest that weeks of cruising do not teach infants a basic fact about walking: the necessity of a floor to support their body. Moreover, this research demonstrated that developmental milestones that are temporally contiguous and structurally similar might have important functional discontinuities.

  5. Coined quantum walks on percolation graphs

    NASA Astrophysics Data System (ADS)

    Leung, Godfrey; Knott, Paul; Bailey, Joe; Kendon, Viv

    2010-12-01

    Quantum walks, both discrete (coined) and continuous time, form the basis of several quantum algorithms and have been used to model processes such as transport in spin chains and quantum chemistry. The enhanced spreading and mixing properties of quantum walks compared with their classical counterparts have been well studied on regular structures and also shown to be sensitive to defects and imperfections in the lattice. As a simple example of a disordered system, we consider percolation lattices, in which edges or sites are randomly missing, interrupting the progress of the quantum walk. We use numerical simulation to study the properties of coined quantum walks on these percolation lattices in one and two dimensions. In one dimension (the line), we introduce a simple notion of quantum tunnelling and determine how this affects the properties of the quantum walk as it spreads. On two-dimensional percolation lattices, we show how the spreading rate varies from linear in the number of steps down to zero as the percolation probability decreases towards the critical point. This provides an example of fractional scaling in quantum-walk dynamics.

  6. Convergence of quantum random walks with decoherence

    SciTech Connect

    Fan Shimao; Feng Zhiyong; Yang, Wei-Shih; Xiong Sheng

    2011-10-15

    In this paper, we study the discrete-time quantum random walks on a line subject to decoherence. The convergence of the rescaled position probability distribution p(x,t) depends mainly on the spectrum of the superoperator L{sub kk}. We show that if 1 is an eigenvalue of the superoperator with multiplicity one and there is no other eigenvalue whose modulus equals 1, then P(({nu}/{radical}(t)),t) converges to a convex combination of normal distributions. In terms of position space, the rescaled probability mass function p{sub t}(x,t){identical_to}p({radical}(t)x,t), x is an element of Z/{radical}(t), converges in distribution to a continuous convex combination of normal distributions. We give a necessary and sufficient condition for a U(2) decoherent quantum walk that satisfies the eigenvalue conditions. We also give a complete description of the behavior of quantum walks whose eigenvalues do not satisfy these assumptions. Specific examples such as the Hadamard walk and walks under real and complex rotations are illustrated. For the O(2) quantum random walks, an explicit formula is provided for the scaling limit of p(x,t) and their moments. We also obtain exact critical exponents for their moments at the critical point and show universality classes with respect to these critical exponents.

  7. Prevention of downhill walking-induced muscle damage by non-damaging downhill walking

    PubMed Central

    Yamamoto, Masayoshi; Kanehisa, Hiroaki; Nosaka, Kazunori

    2017-01-01

    Purpose Mountain trekking involves level, uphill, and downhill walking (DW). Prolonged DW induces damage to leg muscles, reducing force generating ability and muscle coordination. These increase risks for more serious injuries and accidents in mountain trekking, thus a strategy to minimize muscle damage is warranted. It has been shown that low-intensity eccentric contractions confer protective effect on muscle damage induced by high-intensity eccentric contractions. This study tested the hypothesis that 5-min non-damaging DW would attenuate muscle damage induced by 40-min DW, but 5-min level walking (LW) would not. Methods Untrained young men were allocated (n = 12/group) to either a control or one of the two preconditioning groups (PRE-DW or PRE-LW). The PRE-DW and PRE-LW groups performed 5-min DW (-28%) and 5-min LW, respectively, at 5 km/h with a load of 10% body mass, 1 week before 40-min DW (-28%, 5 km/h, 10% load). The control group performed 40-min DW only. Maximal knee extension strength, plasma creatine kinase (CK) activity, and muscle soreness (0–100 mm visual analogue scale) were measured before and 24 h after 5-min DW and 5-min LW, and before and 24, 48, and 72 h after 40-min DW. Results No significant changes in any variables were evident after 5-min DW and 5-min LW. After 40-min DW, the control and PRE-LW groups showed significant (P<0.05) changes in the variables without significant differences between groups (control vs. PRE-LW; peak strength reduction: -19.2 ± 6.9% vs. -18.7 ± 11.0%, peak CK: 635.5 ± 306.0 vs. 639.6 ± 405.4 U/L, peak soreness: 81.4 ± 14.8 vs. 72.0 ± 29.2 mm). These changes were significantly (P<0.05) attenuated (47–64%) for the PRE-DW group (-9.9 ± 9.6%, 339.3 ± 148.4 U/L, 27.8 ± 16.8 mm). Conclusions The results supported the hypothesis and suggest that performing small volume of downhill walking is crucial in preparation for trekking. PMID:28288187

  8. Evolving a Behavioral Repertoire for a Walking Robot.

    PubMed

    Cully, A; Mouret, J-B

    2016-01-01

    Numerous algorithms have been proposed to allow legged robots to learn to walk. However, most of these algorithms are devised to learn walking in a straight line, which is not sufficient to accomplish any real-world mission. Here we introduce the Transferability-based Behavioral Repertoire Evolution algorithm (TBR-Evolution), a novel evolutionary algorithm that simultaneously discovers several hundreds of simple walking controllers, one for each possible direction. By taking advantage of solutions that are usually discarded by evolutionary processes, TBR-Evolution is substantially faster than independently evolving each controller. Our technique relies on two methods: (1) novelty search with local competition, which searches for both high-performing and diverse solutions, and (2) the transferability approach, which combines simulations and real tests to evolve controllers for a physical robot. We evaluate this new technique on a hexapod robot. Results show that with only a few dozen short experiments performed on the robot, the algorithm learns a repertoire of controllers that allows the robot to reach every point in its reachable space. Overall, TBR-Evolution introduced a new kind of learning algorithm that simultaneously optimizes all the achievable behaviors of a robot.

  9. Walknet, a bio-inspired controller for hexapod walking.

    PubMed

    Schilling, Malte; Hoinville, Thierry; Schmitz, Josef; Cruse, Holk

    2013-08-01

    Walknet comprises an artificial neural network that allows for the simulation of a considerable amount of behavioral data obtained from walking and standing stick insects. It has been tested by kinematic and dynamic simulations as well as on a number of six-legged robots. Over the years, various different expansions of this network have been provided leading to different versions of Walknet. This review summarizes the most important biological findings described by Walknet and how they can be simulated. Walknet shows how a number of properties observed in insects may emerge from a decentralized architecture. Examples are the continuum of so-called "gaits," coordination of up to 18 leg joints during stance when walking forward or backward over uneven surfaces and negotiation of curves, dealing with leg loss, as well as being able following motion trajectories without explicit precalculation. The different Walknet versions are compared to other approaches describing insect-inspired hexapod walking. Finally, we briefly address the ability of this decentralized reactive controller to form the basis for the simulation of higher-level cognitive faculties exceeding the capabilities of insects.

  10. Did we see someone shake hands with a fire hydrant?: collaborative recall affects false recollections from a campus walk.

    PubMed

    Seamon, John G; Blumenson, Claire N; Karp, Sophie R; Perl, Jesse J; Rindlaub, Laura A; Speisman, Brittany B

    2009-01-01

    An experimenter presented familiar and bizarre action statements (e.g., "Rest on the fire hydrant" vs. "Shake hands with the fire hydrant") to a participant and confederate during a campus walk. They watched the experimenter perform half the actions and imagined the experimenter performing the other half. One day later, they took a second walk where actions were only imagined. Some actions from the first walk were repeated, and new actions were added. Two weeks later, the participant and confederate collaboratively recalled whether specific actions were presented in the first walk and, if so, whether they were imagined or performed. For different actions, the confederate was accurate, was inaccurate, or provided no information. When later tested individually, participants demonstrated imagination inflation by falsely remembering familiar and bizarre actions as performed on the first walk that were merely imagined on the second. These memory errors were greatly reduced if the confederate was accurate during collaborative recall.

  11. Quantitative measures of walking and strength provide insight into brain corticospinal tract pathology in multiple sclerosis.

    PubMed

    Fritz, Nora E; Keller, Jennifer; Calabresi, Peter A; Zackowski, Kathleen M

    2017-01-01

    At least 85% of individuals with multiple sclerosis report walking dysfunction as their primary complaint. Walking and strength measures are common clinical measures to mark increasing disability or improvement with rehabilitation. Previous studies have shown an association between strength or walking ability and spinal cord MRI measures, and strength measures with brainstem corticospinal tract magnetization transfer ratio. However, the relationship between walking performance and brain corticospinal tract magnetization transfer imaging measures and the contribution of clinical measurements of walking and strength to the underlying integrity of the corticospinal tract has not been explored in multiple sclerosis. The objectives of this study were explore the relationship of quantitative measures of walking and strength to whole-brain corticospinal tract-specific MRI measures and to determine the contribution of quantitative measures of function in addition to basic clinical measures (age, gender, symptom duration and Expanded Disability Status Scale) to structural imaging measures of the corticospinal tract. We hypothesized that quantitative walking and strength measures would be related to brain corticospinal tract-specific measures, and would provide insight into the heterogeneity of brain pathology. Twenty-nine individuals with relapsing-remitting multiple sclerosis (mean(SD) age 48.7 (11.5) years; symptom duration 11.9(8.7); 17 females; median[range] Expanded Disability Status Scale 4.0 [1.0-6.5]) and 29 age and gender-matched healthy controls (age 50.8(11.6) years; 20 females) participated in clinical tests of strength and walking (Timed Up and Go, Timed 25 Foot Walk, Two Minute Walk Test ) as well as 3 T imaging including diffusion tensor imaging and magnetization transfer imaging. Individuals with multiple sclerosis were weaker (p = 0.0024) and walked slower (p = 0.0013) compared to controls. Quantitative measures of walking and strength were

  12. Walking function in clinical monitoring of multiple sclerosis by telemedicine.

    PubMed

    Sola-Valls, Núria; Blanco, Yolanda; Sepúlveda, Maria; Llufriu, Sara; Martínez-Lapiscina, Elena H; La Puma, Delon; Graus, Francesc; Villoslada, Pablo; Saiz, Albert

    2015-07-01

    Walking limitation is a key component of disability in patients with multiple sclerosis (MS), but the information on daily walking activity and disability over time is limited. To determine, (1) the agreement between the standard measurements of MS-related disability [expanded disability status scale (EDSS), functional systems (FS) and ambulation index (AI)] obtained by conventional and remote evaluation using a multimedia platform; (2) the usefulness of monitoring 6-min walk test (6MWT) and average daily walking activity (aDWA) to better characterize patients disability. Twenty-five patients (EDSS score 1.0-6.5) were evaluated every 3 months for the first year, and aDWA repeated at year 2. Remote visits included the recording of a video with self-performed neurological examination and specific multimedia questionnaires. aDWA was measured by a triaxial accelerometer. All but two patients completed the study. Modest agreement between conventional and multimedia EDSS was found for EDSS ≤ 4.0 (kappa = 0.2) and good for EDSS ≥ 4.5 (kappa = 0.6). For the overall sample, pyramidal, cerebellar and brainstem FS showed the greatest agreement (kappa = 0.7). SR-AI showed a modest agreement for EDSS ≤ 4.0 and good for EDSS ≥ 4.5 (kappa = 0.3 and 0.6, respectively). There was a strong correlation between conventional and 6MWT measured by accelerometer (r = 0.76). The aDWA correlated strongly with the EDSS (r = -0.86) and a cut-off point of 3279.3 steps/day discriminated patients with ambulatory impairment. There was a significant decline in aDWA over 2 years in patients with ambulatory impairment that were not observed by standard measurements of disability. MS clinical monitoring by telemedicine is feasible, but the observed lower agreement in less disabled patients emphasizes the need to optimize the assessment methodology. Accelerometers capture changes that may indicate deterioration over time.

  13. Quantum walks with tuneable self-avoidance in one dimension

    NASA Astrophysics Data System (ADS)

    Camilleri, Elizabeth; Rohde, Peter P.; Twamley, Jason

    2014-04-01

    Quantum walks exhibit many unique characteristics compared to classical random walks. In the classical setting, self-avoiding random walks have been studied as a variation on the usual classical random walk. Here the walker has memory of its previous locations and preferentially avoids stepping back to locations where it has previously resided. Classical self-avoiding random walks have found numerous algorithmic applications, most notably in the modelling of protein folding. We consider the analogous problem in the quantum setting - a quantum walk in one dimension with tunable levels of self-avoidance. We complement a quantum walk with a memory register that records where the walker has previously resided. The walker is then able to avoid returning back to previously visited sites or apply more general memory conditioned operations to control the walk. We characterise this walk by examining the variance of the walker's distribution against time, the standard metric for quantifying how quantum or classical a walk is. We parameterise the strength of the memory recording and the strength of the memory back-action on the walker, and investigate their effect on the dynamics of the walk. We find that by manipulating these parameters, which dictate the degree of self-avoidance, the walk can be made to reproduce ideal quantum or classical random walk statistics, or a plethora of more elaborate diffusive phenomena. In some parameter regimes we observe a close correspondence between classical self-avoiding random walks and the quantum self-avoiding walk.

  14. Head and body stabilization in blowflies walking on differently structured substrates.

    PubMed

    Kress, Daniel; Egelhaaf, Martin

    2012-05-01

    Visually guided animals depend heavily on the quality of visual signals in order to obtain functionally relevant information about their environment. To support visual information processing, nature has evolved a large variety of physiological adaptations and behavioral strategies such as compensatory head movements. During self-movement, head rotations compensate for changes in body attitude in order to stabilize gaze. However, how walking animals cope with uneven structured substrates, which may affect body and gaze orientation, is still unknown. We used stereo high-speed video to analyze compensatory head movements of blowflies walking freely on differently structured substrates. We found that even a pronounced asperity of the ground structure, with bumps of almost the size of the animal, was largely compensated by the walking apparatus of the blowfly, which leads to body roll and pitch movements only marginally larger than those on flat substrate. Pitch and roll fluctuations of the head were smaller compared with body fluctuations on all tested substrates, emphasizing the significance of gaze stabilization during walking on structured substrates. Furthermore, we found no impairment in head and body stabilization during walks in darkness, which indicates that the control system mediating compensatory head movements works well without any visual input. Interestingly, blowflies changed their walking style in the dark and seemed to use their forelegs as tactile probes.

  15. Gait and six-minute walk performance in persons with multiple sclerosis.

    PubMed

    Pilutti, Lara A; Dlugonski, Deirdre; Sandroff, Brian M; Suh, Yoojin; Pula, John H; Sosnoff, Jacob J; Motl, Robert W

    2013-11-15

    The six-minute walk (6 MW) has been established as a clinic-based, performance measure of walking endurance that reflects community ambulation in multiple sclerosis (MS). Consequently, identifying the contribution of variables to 6 MW performance may provide targets for improving real-life walking in MS, and these variables may differ as a function of disability. This study examined cadence and stride length as gait variables that explain differences in 6 MW performance between persons with MS and controls, and by level of disability. 256 community-residing persons with MS and 49 non-MS controls performed a standard 6 MW test and completed 2 trials of comfortable walking on an electronic walkway for quantifying gait. Regression analyses indicated that cadence and stride length explain differences in 6 MW performance between MS and controls, and by level of disability in MS. The contribution of cadence and stride length to walking endurance differed as a function of disability, such that cadence and to a greater extent stride length explained variance in 6 MW performance in mild MS, whereas cadence and stride length explained approximately an equivalent amount of variance in 6 MW performance in moderate-to-severe MS. We provide evidence for intervention strategies that are specific to disability level to improve walking endurance in MS.

  16. Maximum walking speeds obtained using treadmill and overground robot system in persons with post-stroke hemiplegia

    PubMed Central

    2012-01-01

    Background Previous studies demonstrated that stroke survivors have a limited capacity to increase their walking speeds beyond their self-selected maximum walking speed (SMWS). The purpose of this study was to determine the capacity of stroke survivors to reach faster speeds than their SMWS while walking on a treadmill belt or while being pushed by a robotic system (i.e. “push mode”). Methods Eighteen chronic stroke survivors with hemiplegia were involved in the study. We calculated their self-selected comfortable walking speed (SCWS) and SMWS overground using a 5-meter walk test (5-MWT). Then, they were exposed to walking at increased speeds, on a treadmill and while in “push mode” in an overground robotic device, the KineAssist, until they were tested at a speed that they could not sustain without losing balance. We recorded the time and number of steps during each trial and calculated gait speed, average cadence and average step length. Results Maximum walking speed in the “push mode” was 13% higher than the maximum walking speed on the treadmill and both were higher (“push mode”: 61%; treadmill: 40%) than the maximum walking speed overground. Subjects achieved these faster speeds by initially increasing both step length and cadence and, once individuals stopped increasing their step length, by only increasing cadence. Conclusions With post-stroke hemiplegia, individuals are able to walk at faster speeds than their SMWS overground, when provided with a safe environment that provides external forces that requires them to attempt dynamic stability maintenance at higher gait speeds. Therefore, this study suggests the possibility that, given the appropriate conditions, people post-stroke can be trained at higher speeds than previously attempted. PMID:23057500

  17. Implementation of interval walking training in patients with type 2 diabetes in Denmark: rationale, design, and baseline characteristics

    PubMed Central

    Ried-Larsen, Mathias; Thomsen, Reimar W; Berencsi, Klara; Brinkløv, Cecilie F; Brøns, Charlotte; Valentiner, Laura S; Karstoft, Kristian; Langberg, Henning; Vaag, Allan A; Pedersen, Bente K; Nielsen, Jens S

    2016-01-01

    Promoting physical activity is a first-line choice of treatment for patients with type 2 diabetes (T2D). However, there is a need for more effective tools and technologies to facilitate structured lifestyle interventions and to ensure a better compliance, sustainability, and health benefits of exercise training in patients with T2D. The InterWalk initiative and its innovative application (app) for smartphones described in this study were developed by the Danish Centre for Strategic Research in T2D aiming at implementing, testing, and validating interval walking in patients with T2D in Denmark. The interval walking training approach consists of repetitive 3-minute cycles of slow and fast walking with simultaneous intensity guiding, based on the exercise capacity of the user. The individual intensity during slow and fast walking is determined by a short initial self-conducted and audio-guided fitness test, which combined with automated audio instructions strives to motivate the individual to adjust the intensity to the predetermined individualized walking intensities. The InterWalk app data are collected prospectively from all users and will be linked to the unique Danish nationwide databases and administrative registries, allowing extensive epidemiological studies of exercise in patients with T2D, such as the level of adherence to InterWalk training and long-term effectiveness surveys of important health outcomes, including cardiovascular morbidity and mortality. Currently, the InterWalk app has been downloaded by >30,000 persons, and the achieved epidemiological data quality is encouraging. Of the 9,466 persons providing personal information, 80% of the men and 62% women were overweight or obese (body mass index ≥25). The InterWalk project represents a contemporary technology-driven public health approach to monitor real-life exercise adherence and to propagate improved health through exercise intervention in T2D and in the general population. PMID:27354828

  18. Examining links between anxiety, reinvestment and walking when talking by older adults during adaptive gait.

    PubMed

    Young, William R; Olonilua, Mayowa; Masters, Rich S W; Dimitriadis, Stefanos; Mark Williams, A

    2016-01-01

    Falls by older adults often result in reduced quality of life and debilitating fear of further falls. Stopping walking when talking (SWWT) is a significant predictor of future falls by older adults and is thought to reflect age-related increases in attentional demands of walking. We examine whether SWWT is associated with use of explicit movement cues during locomotion, and evaluate if conscious control (i.e. movement specific reinvestment) is causally linked to fall-related anxiety during a complex walking task. We observed whether twenty-four older adults stopped walking when talking when asked a question during an adaptive gait task. After certain trials, participants completed a visuospatial recall task regarding walkway features, or answered questions about their movements during the walk. In a subsequent experimental condition, participants completed the walking task under conditions of raised postural threat. Compared to a control group, participants who SWWT reported higher scores for aspects of reinvestment relating to conscious motor processing but not movement self-consciousness. The higher scores for conscious motor processing were preserved when scores representing cognitive function were included as a covariate. There were no group differences in measures of general cognitive function, visuospatial working memory or balance confidence. However, the SWWT group reported higher scores on a test of external awareness when walking, indicating allocation of attention away from task-relevant environmental features. Under conditions of increased threat, participants self-reported significantly greater state anxiety and reinvestment and displayed more accurate responses about their movements during the task. SWWT is not associated solely with age-related cognitive decline or generic increases in age-related attentional demands of walking. SWWT may be caused by competition for phonological resources of working memory associated with consciously processing motor

  19. Thinking About Walking: Effects of Conscious Correction Versus Distraction on Locomotor Adaptation

    PubMed Central

    Malone, Laura A.

    2010-01-01

    Control of the human walking pattern normally requires little thought, with conscious control used only in the face of a challenging environment or a perturbation. We have previously shown that people can adapt spatial and temporal aspects of walking to a sustained perturbation generated by a split-belt treadmill. Here we tested whether conscious correction of walking, versus distraction from it, modifies adaptation. Conscious correction of stepping may expedite the adaptive process and help to form a new walking pattern. However, because walking is normally an automatic process, it is possible that conscious effort could interfere with adaptation, whereas distraction might improve it by removing competing voluntary control. Three groups of subjects were studied: a control group was given no specific instructions, a conscious correction group was instructed how to step and given intermittent visual feedback of stepping during adaptation, and a distraction group performed a dual-task during adaptation. After adaptation, retention of aftereffects was assessed in all groups during normal treadmill walking without conscious effort, feedback, or distraction. We found that conscious correction speeds adaptation, whereas distraction slows it. Subjects trained with distraction retained aftereffects longest, suggesting that the training used during adaptation predicts the time course of deadaptation. An unexpected finding was that these manipulations affected the adaptation rate of spatial but not temporal elements of walking. Thus conscious processes can preferentially access the spatial walking pattern. It may be that spatial and temporal controls of locomotion are accessible through distinct neural circuits, with the former being most sensitive to conscious effort or distraction. PMID:20147417

  20. Similarity of Center of Pressure Progression during Walking and Jogging of Anterior Cruciate Ligament Deficient Patients

    PubMed Central

    Huang, Hongshi; Qiu, Jianwei; Liu, Tianlin; Yu, Yuanyuan; Guo, Qinwei; Luo, Dingsheng; Ao, Yingfang

    2017-01-01

    Objective To evaluate the center of pressure (COP) progression similarity and its change during walking and jogging in Anterior Cruciate Ligament deficient (ACLD) patients. Methods A study was performed in 64 unilateral ACLD subjects and 32 healthy volunteers who walked and jogged on footscan® system at a self-selected speed. COP trajectory during walking and jogging was calculated. The robustness and similarity scores of COP (SSCOP, similarity scores with respect to corresponding COP trajectories) were computed, and then the Analysis of Variance test was employed to compare among different conditions (left or right side, within a subject or between subjects, walking or jogging). Results (1) During the same motion status (walking or jogging), SSCOP were higher than 0.885. However, SSCOP between walking and jogging were lower than 0.25 in both the healthy and ACLD group. SSCOP between the intrasubjects were statistically higher than those between the intersubjects (p<0.01). (2) SSCOP in the ACLD group were statistically significantly reduced to 0.885±0.074 compared to 0.912±0.057 in healthy volunteers during walking, and 0.903±0.066 in the ACLD group compared to 0.919±0.050 in the healthy group during jogging (p<0.01). Conclusions SSCOP can distinguish walking from jogging, and SSCOP of ACLD patients would be different from that of healthy controls. The study protocol was approved by the Institutional Research Board of Peking University Third Hospital (IRB00006761-2012010). PMID:28072874

  1. Construct validity of the walk ratio as a measure of gait control in people with multiple sclerosis without mobility aids.

    PubMed

    Kalron, Alon

    2016-06-01

    Ambulatory limitations are a key component of disability in people with multiple sclerosis (PwMS). Various tools are employed to assess walking performance in PwMS; however, no ideal measure has as yet been attained. In this situation, a walk ratio might be more advantageous compared with other gait measures. The walk ratio, a simple index for describing temporal and spatial co-ordination, denotes the relationship between step length and cadence during walking. Hence, the primary objective of this study was to determine the relationship between the walk ratio and measures of other theoretically related constructs. The walk ratio was studied using the GAITRite™ system (CIR Systems, Inc. Havertown, USA). The study group included 229 PwMS (143 women) and a mean disease duration of 5.8 (SD=7.1) years. The walk ratio score of the total sample was 5.3 (SD=0.8). Significant differences based on the expanded disability status scale (EDSS) scores (F=11.616, P<0.001) were observed between the neurological disability subgroups. Scores of the very mild (EDSS 0-2.0), mild (EDSS 2.5-4.0) and moderate (EDSS 4.5-5.5) groups were 5.5 (SD=0.7), 5.2 (SD=0.7), 4.9 (SD=0.9), respectively. In terms of fall status, the MS fallers demonstrated a significant lower walk ratio compared to the MS non-fallers; 5.1 (SD=0.8) vs. 5.5 (SD=0.7); P<0.001. Modest significant correlation scores were found between walk ratio and ambulation tests. Scores were slightly higher in the short walking tests, timed 25-foot walk and timed up and go tests (Pearson's rho=0.369, 0.364) compared to the 6 and 2-min walk time tests (Pearson's rho=0.344, 0.308). Collectively, the current study supports the construct validity of the walk ratio index in PwMS without mobility aids.

  2. Isolating gait-related movement artifacts in electroencephalography during human walking

    PubMed Central

    Kline, Julia E.; Huang, Helen J.; Snyder, Kristine L.; Ferris, Daniel P.

    2016-01-01

    Objective High-density electroencephelography (EEG) can provide insight into human brain function during real-world activities with walking. Some recent studies have used EEG to characterize brain activity during walking, but the relative contributions of movement artifact and electrocortical activity have been difficult to quantify. We aimed to characterize movement artifact recorded by EEG electrodes at a range of walking speeds and to test the efficacy of artifact removal methods. We also quantified the similarity between movement artifact recorded by EEG electrodes and a head-mounted accelerometer. Approach We used a novel experimental method to isolate and record movement artifact with EEG electrodes during walking. We blocked electrophysiological signals using a nonconductive layer (silicone swim cap) and simulated an electrically conductive scalp on top of the swim cap using a wig coated with conductive gel. We recorded motion artifact EEG data from nine young human subjects walking on a treadmill at speeds from 0.4–1.6 m/s. We then tested artifact removal methods including moving average and wavelet-based techniques. Main Results Movement artifact recorded with EEG electrodes varied considerably, across speed, subject, and electrode location. The movement artifact measured with EEG electrodes did not correlate well with head acceleration. All of the tested artifact removal methods attenuated low-frequency noise but did not completely remove movement artifact. The spectral power fluctuations in the movement artifact data resembled data from some previously published studies of EEG during walking. Significance Our results suggest that EEG data recorded during walking likely contains substantial movement artifact that: cannot be explained by head accelerations; varies across speed, subject, and channel; and cannot be removed using traditional signal processing methods. Future studies should focus on more sophisticated methods for removing of EEG movement

  3. Isolating gait-related movement artifacts in electroencephalography during human walking

    NASA Astrophysics Data System (ADS)

    Kline, Julia E.; Huang, Helen J.; Snyder, Kristine L.; Ferris, Daniel P.

    2015-08-01

    Objective. High-density electroencephelography (EEG) can provide an insight into human brain function during real-world activities with walking. Some recent studies have used EEG to characterize brain activity during walking, but the relative contributions of movement artifact and electrocortical activity have been difficult to quantify. We aimed to characterize movement artifact recorded by EEG electrodes at a range of walking speeds and to test the efficacy of artifact removal methods. We also quantified the similarity between movement artifact recorded by EEG electrodes and a head-mounted accelerometer. Approach. We used a novel experimental method to isolate and record movement artifact with EEG electrodes during walking. We blocked electrophysiological signals using a nonconductive layer (silicone swim cap) and simulated an electrically conductive scalp on top of the swim cap using a wig coated with conductive gel. We recorded motion artifact EEG data from nine young human subjects walking on a treadmill at speeds from 0.4 to 1.6 m s-1. We then tested artifact removal methods including moving average and wavelet-based techniques. Main results. Movement artifact recorded with EEG electrodes varied considerably, across speed, subject, and electrode location. The movement artifact measured with EEG electrodes did not correlate well with head acceleration. All of the tested artifact removal methods attenuated low-frequency noise but did not completely remove movement artifact. The spectral power fluctuations in the movement artifact data resembled data from some previously published studies of EEG during walking. Significance. Our results suggest that EEG data recorded during walking likely contains substantial movement artifact that: cannot be explained by head accelerations; varies across speed, subject, and channel; and cannot be removed using traditional signal processing methods. Future studies should focus on more sophisticated methods for removal of EEG

  4. 40 CFR 89.408 - Post-test procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... between the span-zero response and the hangup zero response shall not be greater than 5.0 percent of full scale or 10 ppmC whichever is greater. (b) Begin the analyzer span checks within 6 minutes after the completion of the last mode in the test. Record for each analyzer the zero and span response (c) If...

  5. 40 CFR 89.408 - Post-test procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... between the span-zero response and the hangup zero response shall not be greater than 5.0 percent of full scale or 10 ppmC whichever is greater. (b) Begin the analyzer span checks within 6 minutes after the completion of the last mode in the test. Record for each analyzer the zero and span response (c) If...

  6. 40 CFR 89.408 - Post-test procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... between the span-zero response and the hangup zero response shall not be greater than 5.0 percent of full scale or 10 ppmC whichever is greater. (b) Begin the analyzer span checks within 6 minutes after the completion of the last mode in the test. Record for each analyzer the zero and span response (c) If...

  7. Assessing walking behaviors of selected subpopulations.

    PubMed

    Le Masurier, Guy C; Bauman, Adrian E; Corbin, Charles B; Konopack, James F; Umstattd, Renee M; VAN Emmerik, Richard E A

    2008-07-01

    Recent innovations in physical activity (PA) assessment have made it possible to assess the walking behaviors of a wide variety of populations. Objective measurement methods (e.g., pedometers, accelerometers) have been widely used to assess walking and other prevalent types of PA. Questionnaires suitable for international populations (e.g., the International Physical Activity Questionnaire and the Global Physical Activity Questionnaire) and measurement techniques for the assessment of gait patterns in disabled populations allow for the study of walking and its health benefits among many populations. Results of studies using the aforementioned techniques indicate that children are more active than adolescents and adolescents are more active than adults. Males, particularly young males, are typically more active than females. The benefits associated with regular participation in PA for youth and walking for older adults have been well documented, although improvements in the assessments of physical, cognitive, and psychosocial parameters must be made if we are to fully understand the benefits of walking for people of all ages. Most youth meet appropriate age-related PA activity recommendations, but adults, particularly older adults and adults with disabilities, are less likely to meet PA levels necessary for the accrual of health benefits. International studies indicate variation in walking by culture. It is clear, however, that walking is a prevalent form of PA across countries and a movement form that has great potential in global PA promotion. Continued development of measurement techniques that allow for the study of individualized gait patterns will help us add to the already rich body of knowledge on chronically disabled populations and allow for individual prescriptions for these populations.

  8. Framework for discrete-time quantum walks and a symmetric walk on a binary tree

    SciTech Connect

    Dimcovic, Zlatko; Rockwell, Daniel; Milligan, Ian; Burton, Robert M.; Kovchegov, Yevgeniy; Nguyen, Thinh

    2011-09-15

    We formulate a framework for discrete-time quantum walks, motivated by classical random walks with memory. We present a specific representation of the classical walk with memory 2, on which this is based. The framework has no need for coin spaces, it imposes no constraints on the evolution operator other than unitarity, and is unifying of other approaches. As an example we construct a symmetric discrete-time quantum walk on the semi-infinite binary tree. The generating function of the amplitude at the root is computed in closed form, as a function of time and the initial level n in the tree, and we find the asymptotic and a full numerical solution for the amplitude. It exhibits a sharp interference peak and a power-law tail, as opposed to the exponentially decaying tail of a broadly peaked distribution of the classical symmetric random walk on a binary tree. The probability peak is orders of magnitude larger than it is for the classical walk (already at small n). The quantum walk shows a polynomial algorithmic speedup in n over the classical walk, which we conjecture to be of the order 2/3, based on strong trends in data.

  9. Exercise intensity of robot-assisted walking versus overground walking in nonambulatory stroke patients.

    PubMed

    van Nunen, Michiel P M; Gerrits, Karin H L; de Haan, Arnold; Janssen, Thomas W J

    2012-01-01

    It has been suggested that aerobic training should be considered in stroke rehabilitation programs to counteract detrimental health effects and decrease cardiovascular risk caused by inactivity. Robot-assisted treadmill exercise (using a Lokomat device) has the potential to increase the duration of walking therapy relative to conventional overground therapy. We investigated whether exercise intensity during Lokomat therapy is adequate to elicit a training effect and how assistance during walking in the Lokomat affects this exercise intensity. Ten patients with stroke (age 54 +/- 9 yr) walked in both the Lokomat and in a hallway. Furthermore, 10 nondisabled subjects (age 43 +/- 14 yr) walked in the Lokomat at various settings and on a treadmill at various speeds. During walking, oxygen consumption and heart rate were monitored. Results showed that for patients with stroke, exercise intensity did not reach recommended levels (30% heart rate reserve) for aerobic training during Lokomat walking. Furthermore, exercise intensity during walking in the Lokomat (9.3 +/- 1.6 mL/min/kg) was lower than during overground walking (10.4 +/- 1.3 mL/min/kg). Also, different settings of the Lokomat only had small effects on exercise intensity in nondisabled subjects.

  10. 10 CFR 429.53 - Walk-in coolers and walk-in freezers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Walk-in coolers and walk-in freezers. 429.53 Section 429.53 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... WICFs with transparent reach-in doors and windows: The glass type of the doors and windows (e.g.,...

  11. Analysis of Individual Social-ecological Mediators and Moderators and Their Ability to Explain Effect of a Randomized Neighborhood Walking Intervention

    PubMed Central

    Michael, Yvonne L; Carlson, Nichole E

    2009-01-01

    Background Using data from the SHAPE trial, a randomized 6-month neighborhood-based intervention designed to increase walking activity among older adults, this study identified and analyzed social-ecological factors mediating and moderating changes in walking activity. Methods Three potential mediators (social cohesion, walking efficacy, and perception of neighborhood problems) and minutes of brisk walking were assessed at baseline, 3-months, and 6-months. One moderator, neighborhood walkability, was assessed using an administrative GIS database. The mediating effect of change in process variables on change in brisk walking was tested using a product-of-coefficients test, and we evaluated the moderating effect of neighborhood walkability on change in brisk walking by testing the significance of the interaction between walkability and intervention status. Results Only one of the hypothesized mediators, walking efficacy, explained the intervention effect (product of the coefficients (95% CI) = 8.72 (2.53, 15.56). Contrary to hypotheses, perceived neighborhood problems appeared to suppress the intervention effects (product of the coefficients (95% CI = -2.48, -5.6, -0.22). Neighborhood walkability did not moderate the intervention effect. Conclusion Walking efficacy may be an important mediator of lay-lead walking interventions for sedentary older adults. Social-ecologic theory-based analyses can support clinical interventions to elucidate the mediators and moderators responsible for producing intervention effects. PMID:19643024

  12. 16 CFR 1205.33 - Certification testing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... SAFETY STANDARD FOR WALK-BEHIND POWER LAWN MOWERS Certification § 1205.33 Certification testing. (a) General. Manufacturers and importers shall either test each individual rotary walk-behind power lawn mower... requirements of the standard. (b) Reasonable testing program. (1) A reasonable testing program for rotary...

  13. 16 CFR 1205.33 - Certification testing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... SAFETY STANDARD FOR WALK-BEHIND POWER LAWN MOWERS Certification § 1205.33 Certification testing. (a) General. Manufacturers and importers shall either test each individual rotary walk-behind power lawn mower... requirements of the standard. (b) Reasonable testing program. (1) A reasonable testing program for rotary...

  14. 16 CFR 1205.33 - Certification testing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SAFETY STANDARD FOR WALK-BEHIND POWER LAWN MOWERS Certification § 1205.33 Certification testing. (a) General. Manufacturers and importers shall either test each individual rotary walk-behind power lawn mower... requirements of the standard. (b) Reasonable testing program. (1) A reasonable testing program for rotary...

  15. 16 CFR 1205.33 - Certification testing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... SAFETY STANDARD FOR WALK-BEHIND POWER LAWN MOWERS Certification § 1205.33 Certification testing. (a) General. Manufacturers and importers shall either test each individual rotary walk-behind power lawn mower... requirements of the standard. (b) Reasonable testing program. (1) A reasonable testing program for rotary...

  16. 16 CFR 1205.33 - Certification testing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... SAFETY STANDARD FOR WALK-BEHIND POWER LAWN MOWERS Certification § 1205.33 Certification testing. (a) General. Manufacturers and importers shall either test each individual rotary walk-behind power lawn mower... requirements of the standard. (b) Reasonable testing program. (1) A reasonable testing program for rotary...

  17. Torque-stiffness-controlled dynamic walking with central pattern generators.

    PubMed

    Huang, Yan; Vanderborght, Bram; Van Ham, Ronald; Wang, Qining

    2014-12-01

    Walking behavior is modulated by controlling joint torques in most existing passivity-based bipeds. Controlled Passive Walking with adaptable stiffness exhibits controllable natural motions and energy efficient gaits. In this paper, we propose torque-stiffness-controlled dynamic bipedal walking, which extends the concept of Controlled Passive Walking by introducing structured control parameters and a bio-inspired control method with central pattern generators. The proposed walking paradigm is beneficial in clarifying the respective effects of the external actuation and the internal natural dynamics. We present a seven-link biped model to validate the presented walking. Effects of joint torque and joint stiffness on gait selection, walking performance and walking pattern transitions are studied in simulations. The work in this paper develops a new solution of motion control of bipedal robots with adaptable stiffness and provides insights of efficient and sophisticated walking gaits of humans.

  18. A marching-walking hybrid induces step length adaptation and transfers to natural walking.

    PubMed

    Long, Andrew W; Finley, James M; Bastian, Amy J

    2015-06-01

    Walking is highly adaptable to new demands and environments. We have previously studied adaptation of locomotor patterns via a split-belt treadmill, where subjects learn to walk with one foot moving faster than the other. Subjects learn to adapt their walking pattern by changing the location (spatial) and time (temporal) of foot placement. Here we asked whether we can induce adaptation of a specific walking pattern when one limb does not "walk" but instead marches in place (i.e., marching-walking hybrid). The marching leg's movement is limited during the stance phase, and thus certain sensory signals important for walking may be reduced. We hypothesized that this would produce a spatial-temporal strategy different from that of normal split-belt adaptation. Healthy subjects performed two experiments to determine whether they could adapt their spatial-temporal pattern of step lengths during the marching-walking hybrid and whether the learning transfers to over ground walking. Results showed that the hybrid group did adapt their step lengths, but the time course of adaptation and deadaption was slower than that for the split-belt group. We also observed that the hybrid group utilized a mostly spatial strategy whereas the split-belt group utilized both spatial and temporal strategies. Surprisingly, we found no significant difference between the hybrid and split-belt groups in over ground transfer. Moreover, the hybrid group retained more of the learned pattern when they returned to the treadmill. These findings suggest that physical rehabilitation with this marching-walking paradigm on conventional treadmills may produce changes in symmetry comparable to what is observed during split-belt training.

  19. Determining an influencing area affecting walking speed on footpath: A case study of a footpath in CBD Bangkok, Thailand

    NASA Astrophysics Data System (ADS)

    Tipakornkiat, Chalat; Limanond, Thirayoot; Kim, Hyunmyung

    2012-11-01

    Intuitively, the crowd density in front of a pedestrian will affect his walking speed along a footpath. Nevertheless, the size of the influencing area affecting walking speed has rarely been scrutinized in the past. This study attempts to determine the distance in front of pedestrians that principally affects their walking speed under normal conditions, using a case study of a footpath in Bangkok. We recorded pedestrian activities along a test section of 20 m, with an effective walking width of 2.45 m in the morning and at noon. The morning dataset was extracted for analyzing various influencing distances, ranging from 1 to 20 m in front of the pedestrian. The bi-directional walking speed-pedestrian density models were developed, for each tested distance, using linear regression analysis. It was found that an influencing length in the range of 5-8 m yields the highest correlation coefficients. In the case of high density conditions, the walking speed of the equally-split flow (50:50) was found to be higher than other proportional flow analyzed. The finding has useful implications on the improvement of the walking simulations in mesoscopic models.

  20. Does Perceptual-Motor Calibration Generalize across Two Different Forms of Locomotion? Investigations of Walking and Wheelchairs

    PubMed Central

    Kunz, Benjamin R.; Creem-Regehr, Sarah H.; Thompson, William B.

    2013-01-01

    The relationship between biomechanical action and perception of self-motion during walking is typically consistent and well-learned but also adaptable. This perceptual-motor coupling can be recalibrated by creating a mismatch between the visual information for self-motion and walking speed. Perceptual-motor recalibration of locomotion has been demonstrated through effects on subsequent walking without vision, showing that learned perceptual-motor coupling influences a dynamic representation of one's spatial position during walking. Our present studies test whether recalibration of wheelchair locomotion, a novel form of locomotion for typically walking individuals, similarly influences subsequent wheelchair locomotion. Furthermore, we test whether adaptation to the pairing of visual information for self-motion during one form of locomotion transfers to a different locomotion modality. We find strong effects of perceptual-motor recalibration for matched locomotion modalities – walking/walking and wheeling/wheeling. Transfer across incongruent locomotion modalities showed weak recalibration effects. The results have implications both for theories of perceptual-motor calibration mechanisms and their effects on spatial orientation, as well as for practical applications in training and rehabilitation. PMID:23424615