Accelerometer-based body-position sensing for ambulatory electrocardiographic monitoring

Our objective is to validate the ability of 3 appropriately placed accelerometers to determine body position during ambulatory electrocardiographic (ECG) monitoring and to demonstrate the clinical applicability of this method. During ambulatory (Holter) monitoring, the ability to know a patient's position (lying down, sitting, standing, or changing from one position to another) is important in the evaluation of common symptoms such as dizziness, palpitations, and syncope. Changes in body position are also known to alter the electrical axis of the heart, resulting in artifactual changes in QRS amplitude and ST-segment morphology. We have developed an ambulatory patient-monitoring instrument that, through the use of microfabricated accelerometers, can simultaneously record body-position information and 2 channels of ECG data. The accelerometers measure the effects of gravity and dynamic acceleration, allowing determination of a patient's orientation and movements. The accelerometer and ECG signals are input to a portable recorder and are filtered and digitized. Algorithms were developed to automatically determine body position. Ten healthy volunteers wore the device for 1 hour and followed a protocol of standing, sitting, walking, lying supine, and lying in the left and right lateral decubitus positions. An observer manually recorded times of position changes. Data were recorded and analyzed using software designed with MATLAB. The ability of the accelerometers and computer algorithms to determine body position was analyzed in terms of the sensitivity and specificity for each body position. The sensitivities for sitting, standing, walking, lying supine, lying right, and lying left were 98.8%, 99.2%, 95.5%, 99.1%, 98.9%, and 94.8%, respectively. The specificities were 99.7%, 99.4%, 99.6%, 99.0%, 99.8%, and 99.9%, respectively. The use of microfabricated accelerometers is a clinically feasible method to determine body position and can be applied to future studies correlating body position with ECG or other physiologic data.     

Assessment of behavioral changes associated with oral meloxicam administration at time of dehorning in calves using a remote triangulation device and accelerometers

ABSTRACT: BACKGROUND: Dehorning is common in the cattle industry, and there is a need for research evaluating pain mitigation techniques. The objective of this study was to determine the effects of oral meloxicam, a non-steroidal anti-inflammatory, on cattle behavior post-dehorning by monitoring the percent of time spent standing, walking, and lying in specific locations within the pen using accelerometers and a remote triangulation device. Twelve calves approximately ten weeks of age were randomized into 2 treatment groups (meloxicam or control) in a complete block design by body weight. Six calves were orally administered 0.5 mg/kg meloxicam at the time of dehorning and six calves served as negative controls. All calves were dehorned using thermocautery and behavior of each calf was continuously monitored for 7 days after dehorning using accelerometers and a remote triangulation device. Accelerometers monitored lying behavior and the remote triangulation device was used to monitor each calf's movement within the pen. RESULTS: Analysis of behavioral data revealed significant interactions between treatment (meloxicam vs. control) and the number of days post dehorning. Calves that received meloxicam spent more time at the grain bunk on trial days 2 and 6 post-dehorning; spent more time lying down on days 1, 2, 3, and 4; and less time at the hay feeder on days 0 and 1 compared to the control group. Meloxicam calves tended to walk more at the beginning and end of the trial compared to the control group. By day 5, the meloxicam and control group exhibited similar behaviors. CONCLUSIONS: The noted behavioral changes provide evidence of differences associated with meloxicam administration. More studies need to be performed to evaluate the relationship of behavior monitoring and post-operative pain. To our knowledge this is the first published report demonstrating behavioral changes following dehorning using a remote triangulation device in conjunction with accelerometers.     

Triaxial accelerometry for assessment of physical activity in young children

Objective: The purpose of the present study was to derive linear and non‐linear regression equations that estimate energy expenditure (EE) from triaxial accelerometer counts that can be used to quantitate activity in young children. We are unaware of any data regarding the validity of triaxial accelerometry for assessment of physical activity intensity in this age group. Research Methods and Procedures: EE for 27 girls and boys (6.0 ± 0.3 years) was assessed for nine activities (lying down, watching a video while sitting and standing, line drawing for coloring‐in, playing blocks, walking, stair climbing, ball toss, and running) using indirect calorimetry and was then estimated using a triaxial accelerometer (ActivTracer, GMS). Results: Significant correlations were observed between synthetic (synthesized tri‐axes as the vector), vertical, and horizontal accelerometer counts and EE for all activities (0.878 to 0.932 for EE). However, linear and non‐linear regression equations underestimated EE by >30% for stair climbing (up and down) and performing a ball toss. Therefore, linear and non‐linear regression equations were calculated for all activities except these two activities, and then evaluated for all activities. Linear and non‐linear regression equations using combined vertical and horizontal acceleration counts, synthetic counts, and horizontal counts demonstrated a better relationship between accelerometer counts and EE than did regression equations using vertical acceleration counts. Adjustment of the predicted value by the regression equations using the vertical/horizontal counts ratio improved the overestimation of EE for performing a ball toss. Discussion: The results suggest that triaxial accelerometry is a good tool for assessing daily EE in young children.     

Validation of triaxial accelerometers to measure the lying behaviour of adult domestic horses

Examining the characteristics of an animal’s lying behaviour, such as frequency and duration of lying bouts, has become increasingly relevant for animal welfare research. Triaxial accelerometers have the advantage of being able to continuously monitor an animal’s standing and lying behaviour without relying on live observations or video recordings. Multiple models of accelerometers have been validated for use in monitoring dairy cattle; however, no units have been validated for use in equines. This study tested Onset Pendant G data loggers attached to the hind limb of each of two mature Standardbred horses for a period of 5 days. Data loggers were set to record their position every 20 s. Horses were monitored via live observations during the day and by video recordings during the night to compare activity against accelerometer data. All lying events occurred overnight (three to five lying bouts per horse per night). Data collected from the loggers was converted and edited using a macro program to calculate the number of bouts and the length of time each animal spent lying down by hour and by day. A paired t-test showed no significant difference between the video observations and the output from the data loggers (P=0.301). The data loggers did not distinguish standing hipshot from standing square. Predictability, sensitivity, and specificity were all >99%. This study has validated the use of Onset Pendant G data loggers to determine the frequency and duration of standing and lying bouts in adult horses when set to sample and register readings at 20 s intervals.     

Wearable-Sensor-Based Classification Models of Faller Status in Older Adults

Wearable sensors have potential for quantitative, gait-based, point-of-care fall risk assessment that can be easily and quickly implemented in clinical-care and older-adult living environments. This investigation generated models for wearable-sensor based fall-risk classification in older adults and identified the optimal sensor type, location, combination, and modelling method; for walking with and without a cognitive load task. A convenience sample of 100 older individuals (75.5 ± 6.7 years; 76 non-fallers, 24 fallers based on 6 month retrospective fall occurrence) walked 7.62 m under single-task and dual-task conditions while wearing pressure-sensing insoles and tri-axial accelerometers at the head, pelvis, and left and right shanks. Participants also completed the Activities-specific Balance Confidence scale, Community Health Activities Model Program for Seniors questionnaire, six minute walk test, and ranked their fear of falling. Fall risk classification models were assessed for all sensor combinations and three model types: multi-layer perceptron neural network, naïve Bayesian, and support vector machine. The best performing model was a multi-layer perceptron neural network with input parameters from pressure-sensing insoles and head, pelvis, and left shank accelerometers (accuracy = 84%, F1 score = 0.600, MCC score = 0.521). Head sensor-based models had the best performance of the single-sensor models for single-task gait assessment. Single-task gait assessment models outperformed models based on dual-task walking or clinical assessment data. Support vector machines and neural networks were the best modelling technique for fall risk classification. Fall risk classification models developed for point-of-care environments should be developed using support vector machines and neural networks, with a multi-sensor single-task gait assessment.     

Night-time behavior of stabled and pastured peri-parturient ponies

Pregnant and lactating pony mares were observed in two environments, stable and pasture. Twenty-six pony mares were observed on pasture for 2 weeks before and after parturition. The behavior of each mare was recorded every 30 min from 18.00 to 06.00 h. The mutually exclusive behaviors were standing (either standing alert or standing at rest with a hindlimb flexed), grazing (prehending or masticating grass), walking, lying in sternal recumbency and lying in lateral recumbency. The total time-budget for prepartum mares on pasture was 55.3 ± 4.1% grazing, 32.9 ± 3.3% standing, 6.0 ± 1.5% lying in sternal recumbency, 2.7 ± 0.7% walking and 1.4 ± 0.6% lying in lateral recumbency. Grazing and standing occurred at all times, but grazing was most common from 18.00 to 21.00 h and after 05.00 h. Lying was most common between 01.00 and 04.00. Lying in lateral recumbency occurred only after dark, in pre-partum mares. The total time-budget for post-partum mares on pasture was 68.6 ± 4.0% grazing, 22.5 ± 3.0% standing, 4.7 ± 1.0% walking, 4.2 ± 1.2% lying in sternal recumbency and 0.2 ± 0.2% lying in lateral recumbency. Lying in lateral recumbency was seen only at 18.00 h. Lying in sternal recumbency occurred between 21.00 and 04.30 h. More time was spent grazing by the post-partum mares than by the pre-partum mares.The same behaviors were recorded for stabled pony mares except that eating hay rather than grazing constituted the ingestive behavior quantified. The total time-budget for pregnant stabled ponies was 71 ± 3% standing, 15 ± 3% eating, 0.5 ± 0% lying in lateral recumbency, 0.5 ± 0.2% walking and 12.1 ± 2.3% lying in sternal recumbency. Eating decreased and standing increased during the night. Most lying was seen between 01.30 and 05.00 h. Lying in lateral recumbency occurred between 19.30 and 03.30 h. The total nocturnal time-budget of post-partum stalled ponies was 67 ± 3% eating, 19 ± 3% standing and 13.0 ± 2.3% lying in sternal recumbency. Post-partum mares were not observed to walk or to lie in lateral recumbency.The change in behavior after parturition may reflect: (1) nutritional demands of lactation; (2) maternal protective behavior; (3) response to seasonal changes in the environment.     

Actividades diarias evaluadas mediante monitor de actividad de alta precisión en adultos mayores: resultados preliminares del Estudio IMPACT65+

Introduction

Physical activity and physical inactivity patterns can affect health status. In the elderly people, their study is relevant given the importance that they have on the morbidity and mortality.

Duration and frequency of every day activities in total hip patients.

Little knowledge about frequency and duration of daily activities in patients after total hip arthroplasty is available. Such information is required for the definition of realistic load collectives for pre-clinical testing of prostheses. It could also be helpful for the quantitative evaluation of surgery outcome with different prosthesis types. The purpose of this study was to develop and apply a system for the determination of frequency and duration of patient activities in their habitual environment and to compare the results to a clinical outcome score (Harris hip score).A portable activity monitoring system (weight 1.6 kg including batteries) was designed using a Palm top computer, 2 inclination sensors for the thigh and calf and one goniometer positioned at the knee joint. An algorithm was developed to identify frequency and duration of the activities lying, sitting, standing, walking and stair climbing from the signals of the 3 sensors. 42 patients participated in the study and were equipped with the system in the morning at their home. Datasets of 31 patients (age 62.5+/-11.5 y) covered more than 6h (9.8 +/- 1.6 h) and were included in the analysis. Prosthesis specific data as well as the Harris hip score were collected.The most frequent patient activity was sitting (44.3% of the time), followed by standing (24.5%), walking (10.2%), lying (5.8%) and stair climbing (0.4%). The median number of steps/stairs was 6048/164. The number of step cycles representing one year in vivo use should, consequently, be increased to 1.1 million. The Harris hip score (91.4 +/- 9.8) correlated significantly with the number of stairs (r(2) = 0.26, p = 0.003) and showed a positive tendency with the number of steps per day. No differences in activity levels between prosthesis specific factors were found.     

Classification of broiler behaviours using triaxial accelerometer and machine learning

Understanding broiler behaviours provides important implications for animal well-being and farm management. The objectives of this study were to classify specific broiler behaviours by analysing data from wearable accelerometers using two machine learning models, K-Nearest Neighbour (KNN) and Support Vector Machine (SVM). Lightweight triaxial accelerometers were used to record accelerations of nine 7-week-old broilers at a sampling frequency of 40 Hz. A total of 261.6-min data were labelled for four behaviours – walking, resting, feeding and drinking. Instantaneous motion features including magnitude area, vector magnitude, movement variation, energy, and entropy were extracted and stored in a dataset which was then segmented by one of the six window lengths (1, 3, 5, 7, 10 and 20 s) with 50% overlap between consecutive windows. The mean, variation, SD, minimum and maximum of each instantaneous motion feature and two-way correlations of acceleration data were calculated within each window, yielding a total of 43 statistic features for training and testing of machine learning models. Performance of the models was evaluated using pure behaviour datasets (single behaviour type per dataset) and continuous behaviour datasets (continuous recording that involved multiple behaviour types per dataset). For pure behaviour datasets, both KNN and SVM models showed high sensitivities in classifying broiler resting (87% and 85%, respectively) and walking (99% and 99%, respectively). The accuracies of SVM were higher than KNN in differentiating feeding (88% and 75%, respectively) and drinking (83% and 62%, respectively) behaviours. Sliding window with 1-s length yielded the best performance for classifying continuous behaviour datasets. The performance of classification model generally improved as more birds were included for training. In conclusion, classification of specific broiler behaviours can be achieved by recording bird triaxial accelerations and analysing acceleration data through machine learning. Performances of different machine learning models differ in classifying specific broiler behaviours.     

The relationship between physical fitness and ambulatory activity in very elderly women with normal functioning and functional limitations

The effect of daily ambulatory activity on physical fitness has not yet been identified by quantitatively measuring the time spent on the intensity levels of ambulatory activity in elderly women over 75 with different functional capacity levels. The subjects consisted of 147 elderly women over 75 years old (82.8±4.3 years old) who were all capable of performing basic daily activities by themselves. Physical fitness was measured for 7 items (handgrip strength, knee extensor strength, postural stability, stepping, one-legged standing time with eyes open, 10 m walking, and the Timed Up and Go Test). The subjects wore a triaxial accelerometer for 2 consecutive weeks to measure their daily physical activities. The functional capacity level was assessed by the Tokyo Metropolitan Institute of Gerontology Index of Competence. The subjects were divided into two groups, a group with a score ≥10 points (high functional capacity group, n=59) and a score <10 points (low functional capacity group, n=88), and the relationship between physical fitness and physical activity was examined in both groups. In both the high and low functional capacity groups, 10 m walking, the Timed Up and Go Test, and one-legged standing time with eyes open significantly correlated with either the total steps/day or the ambulatory activity intensity. In the high functional capacity group, the knee extensor strength also significantly correlated with the total steps/day and moderate ambulatory activity. It is suggested that very elderly women with a reduced functional capacity should maintain their mobility by simply increasing their daily ambulatory activity.     

Evaluation of a Smartphone-based Human Activity Recognition System in a Daily Living Environment

An evaluation method that includes continuous activities in a daily-living environment was developed for Wearable Mobility Monitoring Systems (WMMS) that attempt to recognize user activities. Participants performed a pre-determined set of daily living actions within a continuous test circuit that included mobility activities (walking, standing, sitting, lying, ascending/descending stairs), daily living tasks (combing hair, brushing teeth, preparing food, eating, washing dishes), and subtle environment changes (opening doors, using an elevator, walking on inclines, traversing staircase landings, walking outdoors). To evaluate WMMS performance on this circuit, fifteen able-bodied participants completed the tasks while wearing a smartphone at their right front pelvis. The WMMS application used smartphone accelerometer and gyroscope signals to classify activity states. A gold standard comparison data set was created by video-recording each trial and manually logging activity onset times. Gold standard and WMMS data were analyzed offline. Three classification sets were calculated for each circuit: (i) mobility or immobility, ii) sit, stand, lie, or walking, and (iii) sit, stand, lie, walking, climbing stairs, or small standing movement. Sensitivities, specificities, and F-Scores for activity categorization and changes-of-state were calculated.The mobile versus immobile classification set had a sensitivity of 86.30% ± 7.2% and specificity of 98.96% ± 0.6%, while the second prediction set had a sensitivity of 88.35% ± 7.80% and specificity of 98.51% ± 0.62%. For the third classification set, sensitivity was 84.92% ± 6.38% and specificity was 98.17 ± 0.62. F1 scores for the first, second and third classification sets were 86.17 ± 6.3, 80.19 ± 6.36, and 78.42 ± 5.96, respectively. This demonstrates that WMMS performance depends on the evaluation protocol in addition to the algorithms. The demonstrated protocol can be used and tailored for evaluating human activity recognition systems in rehabilitation medicine where mobility monitoring may be beneficial in clinical decision-making.     

Access to shade changes behavioral and physiological attributes of dairy cows during the hot season in the subtropics

The effect of shade on behavior and physiological attributes of grazing cows in a high altitude subtropical zone is not well established. This work aimed to investigate how social and ingestive behaviors, as well as physiological and other attributes of dairy cows such as milk production, change in a subtropical environment during the hot season either with or without free access to shade. Fourteen lactating cows were kept on pasture either with no shade or with free access to shade for 5 days and their behavior was recorded with instantaneous scan sampled every 10 min, from sunrise, 0530 h (Greenwich mean time, GMT−0200 h) to sunset, 2100 h (GMT−0200 h). Behavior traits included (1) time spent in activities such as grazing, ruminating, resting, lying, standing, walking, seeking shade and staying in the proximity to the water trough and (2) number of events such as water ingestion, aggressive interactions, as well as competition for shade and water. Physiological attributes such as heart and respiratory rates, rectal temperature, number of rumen movements, panting score, as well as milk yield, were evaluated. Time spent in behavioral activities, number of behavioral events and physiological attributes varied between groups (with and without access to shade). Cows with no shade showed increased respiratory and heart rates and panting score at 1300 h, higher values for time of permanence near the water trough, number of competition and aggression events for shade. On the other hand, they showed lower values for time spent resting while lying, ruminating while standing, seeking shade. Access to shade did not change time spent lying, standing, walking with the head up, ruminating while lying, resting while standing, as well as milk yield and number of ruminal movements. Significant interactions between access to shade and days of measurements were detected for time spent walking, ruminating, grazing, resting, number of water ingestion events, competition events near the water trough and for shade, as well as for rectal temperature and panting score measured at 1700 h. In the high altitude subtropical region, access to shade minimizes negative heat stress effects on behavior and physiological aspects of dairy cows.     

Assessing cow comfort: effects of two floor types and two tie stall designs on the behaviour of lactating dairy cows

Our objective was to test the effects of two types of stall flooring and two tie stall designs on the behaviour of dairy cows. Using two cross-over designs, 16 lactating Holstein cows were housed for 3-week periods in each of four tie stalls to compare the effects of concrete versus mattress flooring, and a narrow versus a wide stall front opening. When cows were housed on a mattress flooring they increased their total lying time by 1.8h per day (51.0 versus 43.4% time per day). The duration of individual lying bouts was longer on concrete flooring (78 versus 62min) and the same was true for the duration of individual bouts of standing (80 versus 48min). On mattress flooring cows stood up and lay down more often than on concrete (28 versus 20 per day, respectively). On concrete cows spent more time standing without eating (35.2 versus 28.1% of sampling observations). Cows consistently made use of the additional space provided with the wide stall front opening, placing their head in the manger area during 70.6% of lying observations compared to only 43.4% of observations in the narrow stall front. However, measures of general activity were not significantly different for the two stall designs. Cows spent similar amounts of time eating and consumed similar quantities of feed in all four tie stalls. Our results suggest a lack of comfort may be apparent in reduced time spent lying and a subsequent increase in time spent standing without eating. A lower frequency of standing and lying and an increase in the bout duration of lying suggests that cows on concrete flooring have difficulty standing up and lying down.     

Lameness detection via leg-mounted accelerometers on dairy cows on four commercial farms

Lameness in dairy herds is traditionally detected by visual inspection, which is time-consuming and subjective. Compared with healthy cows, lame cows often spend longer time lying down, walk less and change behaviour around feeding time. Accelerometers measuring cow leg activity may assist farmers in detecting lame cows. On four commercial farms, accelerometer data were derived from hind leg-mounted accelerometers on 348 Holstein cows, 53 of them during two lactations. The cows were milked twice daily and had no access to pasture. During a lactation, locomotion score (LS) was assessed on average 2.4 times (s.d. 1.3). Based on daily lying duration, standing duration, walking duration, total number of steps, step frequency, motion index (MI, i.e. total acceleration) for lying, standing and walking, eight accelerometer means and their corresponding coefficient of variation (CV) were calculated for each week immediately before an LS. A principal component analysis was performed to evaluate the relationship between the variables. The effects of LS and farm on the principal components (PC) and on the variables were analysed in a mixed model. The first four PC accounted for 27%, 18%, 12% and 10% of the total variation, respectively. PC1 corresponded to Activity variability due to heavy loading by five CV variables related to standing and walking. PC2 corresponded to Activity level due to heavy loading by MI walking, MI standing and walking duration. PC3 corresponded to Recumbency due to heavy loading by four variables related to lying. PC4 corresponded mainly to Stepping due to heavy loading by step frequency. Activity variability at LS4 was significantly higher than at the lower LS levels. Activity level was significantly higher at LS1 than at LS2, which was significantly higher than at LS4. Recumbency was unaffected by LS. Stepping at LS1 and LS2 was significantly higher than at LS3 and LS4. Activity level was significantly lower on farm 3 compared with farms 1 and 2. Stepping was significantly lower on farms 1 and 3 compared with farms 2 and 4. MI standing indicated increased restlessness while standing when cows increased from LS3 to LS4. Lying duration was only increased in lame cows. In conclusion, Activity level differed already between LS1 and LS2, thus detecting early signs of lameness, particularly through contributions from walking duration and MI walking. Lameness detection models including walking duration, MI walking and MI standing seem worthy of further investigation.     

The behaviour of broiler chickens and its modification by lameness

The behaviour of six replicates of broilers obtained from commercial farms, fed ad-libitum and housed on 23-h light:1-h dark schedule at 20 lx was observed using scan sampling. Comparisons were made between sound birds and those of varying degrees of lameness between 39 and 49 days of age. Sound broilers averaged 76% of their time lying and this increased significantly to 86% in lame birds (gait score 3). Lying also increased with age. Although sound broilers spent only a minor part of the day on their feet, they spent significantly more time standing idle (7%), standing preening (3.5%) and standing eating (4.7%) than lame birds. Walking declined with age, but occupied an average 3.3% of the time of a slaughter-weight broiler. Again, lameness significantly reduced this to a minimal 1.5% in the worst affected birds. Sound birds predominantly chose the usual standing posture for eating, whereas, lame birds lay down to eat for almost half their feeding time. Detailed observations using video records revealed that lameness altered the feeding strategy of broilers. Whereas sound birds fed over 50 times in 24 h, the number of visits to the feeder was reduced with increasing lameness to an average of around 30 in the lamest broilers. However, meal duration was adjusted to give no overall differences in time spent feeding per day. Time spent drinking was also the same for all birds, averaging 3% of the day. The alterations of the time budget, in particular the reductions in activities performed whilst standing, and the different feeding strategies adopted, are consistent with lameness imposing a cost on the affected broilers to the detriment of their welfare.     

Nordic Walking improves daily physical activities in COPD: a randomised controlled trial

Background

In patients with COPD progressive dyspnoea leads to a sedentary lifestyle. To date, no studies exist investigating the effects of Nordic Walking in patients with COPD. Therefore, the aim was to determine the feasibility of Nordic Walking in COPD patients at different disease stages. Furthermore we aimed to determine the short- and long-term effects of Nordic Walking on COPD patients'' daily physical activity pattern as well as on patients exercise capacity.

Methods

Sixty COPD patients were randomised to either Nordic Walking or to a control group. Patients of the Nordic Walking group (n = 30; age: 62 ± 9 years; FEV₁: 48 ± 19% predicted) underwent a three-month outdoor Nordic Walking exercise program consisting of one hour walking at 75% of their initial maximum heart rate three times per week, whereas controls had no exercise intervention. Primary endpoint: daily physical activities (measured by a validated tri-axial accelerometer); secondary endpoint: functional exercise capacity (measured by the six-minute walking distance; 6MWD). Assessment time points in both groups: baseline, after three, six and nine months.

Results

After three month training period, in the Nordic Walking group time spent walking and standing as well as intensity of walking increased (Δ walking time: +14.9 ± 1.9 min/day; Δ standing time: +129 ± 26 min/day; Δ movement intensity: +0.40 ± 0.14 m/s²) while time spent sitting decreased (Δ sitting time: -128 ± 15 min/day) compared to baseline (all: p < 0.01) as well as compared to controls (all: p < 0.01). Furthermore, 6MWD significantly increased compared to baseline (Δ 6MWD: +79 ± 28 meters) as well as compared to controls (both: p < 0.01). These significant improvements were sustained six and nine months after baseline. In contrast, controls showed unchanged daily physical activities and 6MWD compared to baseline for all time points.

Conclusions

Nordic Walking is a feasible, simple and effective physical training modality in COPD. In addition, Nordic Walking has proven to positively impact the daily physical activity pattern of COPD patients under short- and long-term observation.

Clinical trial registration

Nordic Walking improves daily physical activities in COPD: a randomised controlled trial - ISRCTN31525632     

An Evaluation of Exercise Pen Use by Circus Tigers (Pathera tigris tigris)

This study quantified the behavior of 11 tigers during periodic access to an exercise pen throughout the day and night. The study determined the amount of time spent in the pen and the percentage of time spent performing stereotypic pacing, normal locomotor behavior, and lying down while in the pen. Average access to the exercise pen was 10 hr 49 min overnight and 5 hr 30 min during the day. At night, the tigers spent 29.1% of their time in the exercise pen, during which they paced 19.6% and performed normal locomotor behavior for 23.1% of that time. By day, they spent 40.4% of their time in the exercise pen, during which they paced 10.0% and performed normal locomotor behavior 35.7% of that time. The tigers spent the rest of the time in the pen lying down. Overall, tigers will utilize an exercise pen, spending a greater percentage of time in the pen during the day than at night and also performing less stereotyped pacing than at night.     

Gait and posture discrimination in sheep using a tri-axial accelerometer

Temporo-spatial observation of the leg could provide important information about the general condition of an animal, especially for those such as sheep and other free-ranging farm animals that can be difficult to access. Tri-axial accelerometers are capable of collecting vast amounts of data for locomotion and posture observations; however, interpretation and optimization of these data records remain a challenge. The aim of the present study was to introduce an optimized method for gait (walking, trotting and galloping) and posture (standing and lying) discrimination, using the acceleration values recorded by a tri-axial accelerometer mounted on the hind leg of sheep. The acceleration values recorded on the vertical and horizontal axes, as well as the total acceleration values were categorized. The relative frequencies of the acceleration categories (RFACs) were calculated in 3-s epochs. Reliable RFACs for gait and posture discrimination were identified with discriminant function and canonical analyses. Post hoc predictions for the two axes and total acceleration were conducted, using classification functions and classification scores for each epoch. Mahalanobis distances were used to determine the level of accuracy of the method. The highest discriminatory power for gait discrimination yielded four RFACs on the vertical axis, and five RFACs each on the horizontal axis and total acceleration vector. Classification functions showed the highest accuracy for walking and galloping. The highest total accuracy on the vertical and horizontal axes were 90% and 91%, respectively. Regarding posture discrimination, the vertical axis exhibited the highest discriminatory power, with values of RFAC (0, 1]=99.95% for standing; and RFAC (−1, 0]=99.50% for lying. The horizontal axis showed strong discrimination for the lying side of the animal, as values were in the acceleration category of (0, 1] for lying on the left side and (−1, 0] on the right side. The algorithm developed by the method employed in the present study facilitates differentiation of the various types of gait and posture in animals from fewer data records, and produces the most reliable acceleration values from only one axis within a short time frame. The present study introduces an optimized method by which the tri-axial accelerometer can be used in gait and posture discrimination in sheep as an animal model.     

Renal sympathetic nerve activity and arterial pressure responses to changes in postural position of conscious dogs

Experiments were conducted in conscious dogs to determine the relationships between postural position, arterial pressure, and renal sympathetic nerve activity. Observations of the changes in arterial pressure and renal nerve activity were made when animals spontaneously changed postural position from lying to sitting, sitting to standing, standing to sitting, and sitting to lying. Rising to sit from lying down increased arterial pressure from 109 +/- 5 to 125 +/- 3 mm Hg and increased renal nerve activity by 96 +/- 58 microV/sec (61% of control). Movement from the sitting to standing position decreased renal nerve activity by 90 +/- 39 microV/sec (48% of control) without changing mean arterial pressure. Sitting down from standing also did not change arterial pressure, whereas renal nerve activity increased by 56 +/- 17 microV/sec (33% of control). Returning to the lying position (from sitting) decreased arterial pressure, and this hypotension was associated with significant reductions in renal nerve activity. These results indicate that nonuniform changes in sympathetic outflow from the central nervous system must occur to various vascular beds during changes in postural position of conscious dogs. Thus, renal sympathetic outflow may or may not reflect changes in nerve traffic which contribute to alterations in arterial pressure.     

Use of space and activity budgets in relation to age and social status in a captive herd of American bison,Bison bison

A stable herd of 11 captive American bison (Bison bison) of known ages and social rank was studied between June 18 and August 6, 1979 at the Jardin zoologique du Québec, Charlesbourg, Quebec. During the 8-week study, the first author collected scan data of predefined behaviors and locations on all individuals of the herd. Space use analysis revealed extensive occupation of (and preference for) the barn and sand mound by higher-ranking animals and calves, and the tendency for lower-ranked individuals to use alternate, lower-quality sites. Overall, the herd spent an average of 40% of the daytime resting, 25% standing, 23% feeding, and 12% walking/running and group exploring. High-ranking individuals spent significantly more time standing and walking, and less time foraging than average. Most low-ranking individuals spent significantly less time lying, and more time feeding than average. Calves spent significantly more time lying than average. The extra feeding time of low-ranking individuals occurred mostly in early morning and mid-day, when the high-ranking individuals were mostly inactive. Our results suggest differential space and time use in relation to age and social status. The effects of resource limitations caused by captivity conditions, as compared with natural conditions, are discussed in regard to the activity and movement coordination of individuals in this particular captive herd. © 1993 Wiley-Liss, Inc.