Walking Distance Estimation Research Articles

Extending the Range of Treadmill Testing for Patients with Intermittent Claudication

There is a need to evaluate patients with peripheral arterial disease (PAD) with a limited or extended walking distance. We aimed to enable an estimation of walking distance as measured on a frequently used "standard" graded (3.2 km·h(-1), 2% increase per 2 min) protocol for walking distances measured on protocols with a lower or higher workload. Patients with PAD and an absolute claudication distance (ACD) of <500 or between 1000 and 1600 m as measured with the "standard" protocol were included. Four graded study treadmill protocols, two with lower and two with higher workload than the "standard" protocol, were developed. Two study protocols (low or high) and the "standard" protocol were repeated in random order. Quality was determined with the intraclass correlation coefficient and the coefficient of variation. Orthogonal regression analysis was used to predict walking distances on the standard protocol on the basis of the study protocols. Forty-three patients with an ACD <500 m and 23 patients with an ACD between 1000 and 1600 m were included. Because feasibility from the protocols with 2.0 km·h(-1) and 2% increase every 2 min and 4.4 km·h(-1) and 2% increase every minute was highest, they were calibrated against the "standard" protocol, and reliability was comparable with the "standard" protocol. The coefficient of variation between the prediction of walking distance on the "standard" protocol on the basis of the new protocols and the measured distances were in the same range (22%-25%) as the variation measured performing the same treadmill test twice. An accurate estimate of walking distance as measured on a "standard" treadmill protocol can be derived from a protocol with a lower or higher workload.

Changes in the Limb Kinematics and Walking-Distance Estimation After Shank Elongation: Evidence for a Locomotor Body Schema?

When walking, step length provides critical information on traveled distance along the ongoing path [corrected] Little is known on the role that knowledge about body dimensions plays within this process. Here we directly addressed this question by evaluating whether changes in body proportions interfere with computation of traveled distance for targets located outside the reaching space. We studied locomotion and distance estimation in an achondroplastic child (ACH, 11 yr) before and after surgical elongation of the shank segments of both lower limbs and in healthy adults walking on stilts, designed to mimic shank-segment elongation. Kinematic analysis of gait revealed that dynamic coupling of the thigh, shank, and foot segments changed substantially as a result of elongation. Step length remained unvaried, in spite of the significant increase in total limb length ( approximately 1.5-fold). These relatively shorter strides resulted from smaller oscillations of the shank segment, as would be predicted by proportional increments in limb size and not by asymmetrical segmental increment as in the present case (length of thighs was not modified). Distance estimation was measured by walking with eyes closed toward a memorized target. Before surgery, the behavior of ACH was comparable to that of typically developing participants. In contrast, following shank elongation, the ACH walked significantly shorter distances when aiming at the same targets. Comparable changes in limb kinematics, stride length, and estimation of traveled distance were found in adults wearing on stilts, suggesting that path integration errors in both cases were related to alterations in the intersegmental coordination of the walking limbs. The results are consistent with a dynamic locomotor body schema used for controlling step length and path estimation, based on inherent relationships between gait parameters and body proportions.

Validity and Reliability of the FitSense FS-1 Speedometer During Walking and Running

This study examined the criterion-related validity and the reliability of the FitSense FS-1 Speedometer for estimating distance, speed, and energy expenditure (EE) during walking and running. The study was divided into two parts. Part I investigated the validity and the reliability of the FitSense for estimating distance while walking and running around a 400-m track (n = 24). Part II looked at the validity of the FitSense for estimating speed and EE during level treadmill walking (4.8, 6.4, and 8.0 km . h -1 ) and running (8.0, 9.6, and 11.2 km . h -1 ). Twelve of the original 24 subjects completed Part II. The results of Part I indicated that the FitSense accurately estimated walking distance, but it underestimated running distance by an average of 3.5% (p=0.016). Testretest reliability was deemed adequate for both walking and running distance (ICC = 0.87 and 0.84, respectively). In Part II, the FitSense overestimated speed during treadmill walking at 8.0km.h -1 (p<0.001) and underestimated EE at two walking speeds (6.4 and 8.0 km.h -1 ) (p < 0.01). No significant differences were found for speed or EE predictions while running at any speed. In summary, the FitSense FS-1 Speedometer provided valid estimates of walking distance during track tests, and valid estimates of speed during treadmill walking (4.8 and 6.4 km.h -1 ) and running (9.6 and 11.2 km.h -1 ). However, the FitSense underestimated running distance during track tests. In addition, the FitSense overestimated speed and underestimated EE in the transition between walking and running (8.0 km.h -1 ).

The validity of patient and physician estimates of walking distance.

To establish the validity of patient and physician estimates of maximum walking distance versus actual measured maximum walking distance. Assessment of concurrent validity (patient and physician estimates were compared with a gold standard measure at the same time). University-affiliated rehabilitation department in a tertiary care hospital. A sequential sample of 31 patients over the age of 17 referred to the physical medicine and rehabilitation outpatients department between 1 May 2000 and 20 July 2001, who had at least some degree of walking difficulty. Patients and their physicians were asked to provide estimates of walking distance independently after a regular appointment prior to the patient being escorted along a pre-measured walking course. Actual distance walked was compared with estimates using Pearson correlation coefficients. Pearson correlation coefficients for patient estimate versus actual was 0.789 (p < or = 0.0001), and mean estimate of patient and physician estimates versus actual was 0.812 (p < or = 0.0001). Physician estimate versus actual and patient estimate versus physician estimate were 0.349 and -0.139 (neither significant). Sixty-seven per cent (20/30) of patients overestimated how far they thought they could walk versus 23% (7.30) of physicians who overestimated. Neither group were found to be 'good' estimators of maximal walking distance. Neither patients nor physicians provide valid estimates of maximal walking distance. Patients consistently overestimate their maximal walking distance, whereas physicians tend to underestimate. Interestingly, patients' estimates (although over inflated) do correlate well with actual walking distance, while physician estimates are not at all correlated. This study suggests that reliance on self-reported or physician-estimated maximum walking distances (whether for clinical, research or other reasons) is potentially flawed.

213 3 次元歩行距離推定のための積分誤差軽減法

213 3 次元歩行距離推定のための積分誤差軽減法

The Effects of Recording Interval on the Estimation of Grazing Behavior of Cattle in a Daytime Grazing System

The effects of recording interval (1, 2, 3, 4, 5, 10, 15, 20 and 30 min) on the estimation of some grazing behavior variables in beef cows and calves ( rumination time>resting time. An increase in recording interval always decreased estimates of the distance walked by animals. It was concluded that recording intervals of 1-5 min provide reliable estimates of the time spent grazing, ruminating and resting. It was also concluded that positioning of animals at 1 min intervals may provide estimates of walking distance with acceptable bias toward underestimation. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 5 : 745-750)

Estimation of walking distance in intermittent claudication: need for standardization

Estimation of walking distance in intermittent claudication: need for standardization

Measurement of walking endurance and walking velocity with questionnaire: Validation of the walking impairment questionnaire in men and women with peripheral arterial disease

Objectives: The Walking Impairment Questionnaire (WIQ) was designed to measure community walking ability in patients with peripheral arterial disease (PAD) and intermittent claudication. We compared the WIQ scores to objective measures of walking in a heterogeneous group of patients with and without PAD. Methods: The study was designed as a cross-sectional study, with the setting in an academic medical center. The subjects were patients with PAD (n = 145) who were identified from a noninvasive vascular laboratory at an academic medical center. The patients without PAD (n = 65) were identified from a general medicine practice. The average number of comorbidities was 2.03 for patients with PAD and 1.52 for patients without PAD. Among the patients with PAD, 28% had classical intermittent claudication symptoms and 55% had exertional leg symptoms other than claudication. The main outcome measures were the WIQ estimates of the patient-reported walking distance and walking speed on a scale of 0 to 100. Walking endurance was measured objectively with the 6-minute walk. Walking velocity was measured with a 4-m walk. PAD and PAD severity were defined with the ankle brachial index. Results: The Spearman rank correlation coefficients (ρ) between the WIQ distance score and the 6-minute walk score were 0.557 among patients with PAD ( P < .001) and 0.484 among patients without PAD ( P < .001). The correlation coefficients between the WIQ speed score and the usual-paced 4-m walk score were 0.528 among patients with PAD ( P < .001) and 0.524 among patients without PAD ( P < .001). The correlations were not affected by the presence versus the absence of intermittent claudication, by PAD severity, or by the presence of 2 or more versus less than 2 comorbid illnesses. The WIQ scores in the highest and lowest quartiles were the most closely associated with the objective measures of function. Conclusion: The WIQ is a valid measure of community walking ability in a heterogeneous group of patients with and without PAD. The WIQ discriminates best among patients in the highest and the lowest quartiles of walking speed and endurance. (J Vasc Surg 1998;28:1072-81.)