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PubMed1991

Removing the obstacles to effective strategic planning.

The purpose of this article is to explore the reasons for the decline in the importance and practice of strategic planning across American industry. The article identifies numerous bureaucratic obstacles to effective planning, and suggests how these obstacles can most effectively be eliminated by attacking their root causes. The article points out the risks to the planning process that are created by attempts to eliminate these obstacles. But, it concludes that unless these obstacles are removed and the promised financial returns from strategic business planning realized, the decline of long-term strategic business planning will continue.

Decision Making, Organizational↗
PubMed2006

High failure rates when avoiding obstacles during treadmill walking in patients with a transtibial amputation.

OBJECTIVE: To investigate if and to what extent patients with a transtibial amputation are less successful in avoiding unexpected obstacles while walking than healthy adults. DESIGN: Experimental 2-group design. SETTING: Dutch rehabilitation center. PARTICIPANTS: Eleven patients with a transtibial amputation and 14 healthy controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Subjects walked on a treadmill at .56m/s. In 2 series of 12 trials each, an obstacle was dropped in front of the prosthetic or the nonprosthetic leg of the amputation group and the left leg of the control group at different phases during the step cycle. It was noted which avoidance strategy was used (a long step strategy [LSS] or a short step strategy [SSS]) and whether the obstacle was avoided successfully or not. These data were expressed as a percentage of the total number of trials completed by each subject. RESULTS: With either leg, the amputation group made significantly more errors than the control subjects (prosthetic leg, 24%+/-17%; nonprosthetic leg, 21%+/-17% vs 2%+/-2% for the control group). Highest failure rates were in the amputation group when time pressure was high, requiring an SSS, especially on the prosthetic side. An LSS under time pressure, however, nearly always resulted in failure for both the prosthetic and nonprosthetic legs. Subjects with the longest time since amputation were most successful in avoiding unexpected obstacles. CONCLUSIONS: Under time pressure, patients with a lower-leg prosthesis perform best when they use their nonprosthetic leg as the lead limb in an SSS. The fact that some subjects with the longest time since amputation made no errors suggests that over many years it is possible to relearn the appropriate avoidance reactions sufficiently fast.

Adult↗
PubMed2006

Anxiety-mediated gait adaptations reduce errors of obstacle negotiation among younger and older adults: implications for fall risk.

The purpose of this study was to determine if anxiety-mediated gait adaptations can reduce the risk for falling among younger and older adults. Fourteen younger adults (23.14+/-3.08 years) and 14 older adults (69.28+/-5.41 years) participated in this study. Participants were asked to walk the length of a 7.20m walkway and avoid contact with an obstacle that appeared suddenly underfoot at either 25% or 75% of the gait cycle duration. Testing was conducted in four conditions of postural threat. The obstacle was presented as a light beam and did not jeopardize balance when contacted. Fall risk was inferred from the frequency of obstacle contacts. Our findings indicated that obstacle contact frequency decreased when conservative gait patterns emerged. These findings imply that anxiety-mediated gait adaptations are beneficial in reducing the risk for falling among older adults and present the possibility that fear of falling may offer protective benefits for postural control. One possibility is that the beneficial effects of anxiety can only be realized among older adults who do not fear falling.

Accidental Falls↗
PubMed2005

The circumvention of obstacles during walking in different environmental contexts: a comparison between older and younger adults.

Avoiding pedestrians is an integral part of our daily activities, yet this locomotor activity has received little attention in gait research. A recent study [Motor Control 2005;9:242] described the motor strategies used by young adults to circumvent an obstruction in different environmental contexts including obstacle movement, certainty about this obstacle movement and auditory distractions. The relationship between normal aging and such locomotor activity within these different environmental contexts, however, is not known. The purpose of this study was thus to compare the walking speed and the personal space-a protective zone preserved around the body-in healthy younger and older adults during obstacle circumvention in the above mentioned environmental contexts. The movements of nine younger adults (24.6+/-4.1 years) and nine older adults (69.7+/-3.2 years) were measured as they circumvented a stationary or moving mannequin with and without initial knowledge of the obstacle's displacements. Participants also had to pay attention to auditory messages, played in half of the trials, and to answer related questions. Results showed that all three environmental factors resulted in decreased gait speed in both groups, but the effect of auditory distractions was greater in older adults. Older adults also increased their personal space more than younger adults while paying attention to messages and they made more mistakes when answering related questions. Therefore, even if such an avoidance task is performed routinely, the increased information processing demanded by the environmental context affected both the motor and cognitive performance of older adults more than that of younger adults.

Adaptation, Physiological↗
PubMed2005

Possibilities for, and obstacles to, CPR training among cardiac care patients and their co-habitants.

AIM: To investigate the level of cardiopulmonary resuscitation (CPR) training among cardiac patients and their co-habitants and to describe the possibilities for, and obstacles to, CPR training among this group. METHODS: All patients admitted to a coronary care unit during a four-month period were considered for participation in an interview study. Out of 401 patients, 268 were co-habiting. This study deals with these subjects. RESULTS: According to the answers given by the patients, 46% of the patients and 33% of the co-habitants had attended a CPR course at some time. Among those who had not previously attended a course, 58% were willing to attend, and 60% of the patients whose co-habitant had not received CPR education, wanted him or her to attend a course. The major obstacle to CPR training was the patient's own medical status. The major obstacle to the co-habitant's participation was the patient's doubts concerning their partner's physical ability or willingness to participate. Younger persons were more often willing to undergo training than older persons (p < 0.0001). Of those patients who had previously attended a course or who were willing to undergo training, 72% were prepared to do so together with their co-habitant. A course specially designed for cardiac patients and their relatives was a possible alternative for 75% of those willing to participate together with their co-habitant. CONCLUSIONS: Two-thirds of the patients did not believe that their co-habitant had taken part in CPR training. More than half of these would like their co-habitant to attend such a course. Seventy-two percent were willing to participate in CPR instruction together with their co-habitant. Major obstacles to CPR training were doubts concerning the co-habitant's willingness or physical ability and their own medical status.

Aged↗
PubMed1998

Obstacle course performance and risk of falling in community-dwelling elderly persons.

OBJECTIVE: To determine the efficacy of obstacle course performance scores in predicting persons at risk for falls, after adjusting for age, sociodemographic, health-status, and physiologic variables. DESIGN: Correlational descriptive study design utilizing a logistic regression model. SETTING: Community setting. PATIENTS OR PARTICIPANTS: A convenience sample of 352 community-dwelling elderly individuals at sites in a metropolitan area. MAIN CRITERION MEASURE: Number of falls reported prospectively during a 2-year follow-up period. RESULTS: Obstacle course performance, fall history, symptoms of balance dysfunction, and activity level distinguished those who fell and those who did not 12 and 18 months later. At 24 months, range of motion and number of medications also were significant. In multivariate logistic regression, only history of a fall was a significant predictor of future falling at 12 and 18 months; at 24 months, the presence of balance dysfunction symptoms was the significant predictor of those who fell. CONCLUSIONS: The obstacle course, as a predictor of future falls, is not superior to the question of whether or not an individual has fallen in the previous year, and is not recommended to predict future falls. The obstacle course may be better as a short-term indicator of response to a rehabilitation program for balance and mobility.

Accidental Falls↗
PubMed1999

Obstacle crossing in subjects with stroke.

OBJECTIVE: To study the ability of subjects with stroke to successfully step over an obstacle during ambulation. SETTING: A geriatric rehabilitation unit in a tertiary referral hospital. SUBJECTS: Twenty-four inpatients with stroke (median time poststroke 27 days, interquartile range 21 to 44.5 days) able to walk 10 m unassisted without walking aids; also, 22 healthy subjects. METHOD: Subjects were required to step over obstacles of various heights and widths, ranging from 1cm to 8cm. A fail was scored if the obstacle was contacted by either lower limb or if assistance or upper limb support was required. The choice of leading limb and the presence of visual deficits and neglect were also recorded in the stroke subjects. Subjects were tested on two occasions. RESULTS: Significantly more fails were recorded for stroke subjects, with 13 subjects failing at least once. No preference was shown for leading either with the affected or with the unaffected leg. Stroke subjects showed inconsistent performance over the two testing sessions. CONCLUSION: The ability to negotiate obstacles was compromised and inconsistent in stroke subjects undergoing inpatient rehabilitation. This suggests that gait safety in this population remains threatened.

Activities of Daily Living↗
PubMed2001

A dynamical systems investigation of lower extremity coordination during running over obstacles.

OBJECTIVE: To investigate intralimb coordination during running over a level surface and over obstacles of three different heights. DESIGN: The phasing relationships between the foot and leg motions in the frontal plane, and the shank and thigh motions in the sagittal plane were used to compare patterns of coordination. BACKGROUND: The coordinated actions of lower extremity segments are necessary to absorb the impact forces generated during running. The behavioral patterns of these segments can be studied under changing task demands using analysis techniques from the Dynamical Systems Theory. METHODS: Ten subjects ran at their self-selected pace under four conditions: over a level surface and over obstacles of different heights (5%, 10%, 15% of their standing height). A force platform was used to record impact forces during landing after obstacle clearance, while kinematics were collected using a two-camera system. RESULTS: The increases in obstacle height resulted in significant changes in impact forces (34% increase between the two extreme conditions) and more in-phase relationships between the segments during early stance. No changes were observed in the variability of the phasing relationships. CONCLUSIONS: The coordination changes observed might be compensatory strategies aimed to reduce forces and potential injury. However, since the impact forces still increased significantly, it is also possible that the observed changes might be at-risk movement patterns predisposing runners to injury.

Adult↗
PubMed2003

Medio-lateral motion of the center of mass during obstacle crossing distinguishes elderly individuals with imbalance.

This study was performed to investigate whether elderly patients with imbalance can be distinguished from healthy elderly subjects by comparing their whole body center of mass (COM) motion in the medio-lateral (M-L) direction during obstacle crossing. Nine healthy elderly adults and six elderly patients having complaints of 'dizziness' or 'unsteadiness' during walking (three with bilateral/unilateral vestibular weakness and three with unclear diagnosis) were recruited to perform unobstructed level walking and crossing of obstacles set to 2.5, 5, 10 and 15% of each subject's height. Kinematics of the COM was calculated using a weighted sum average of a 13-segment biomechanical model. There were no significant group differences for the temporal-distance gait parameters during all testing conditions. However, elderly patients with balance disorders demonstrated significantly greater and faster lateral motion of the COM when crossing over obstacles. These measurements distinguish elderly patients with imbalance from healthy elderly subjects. Furthermore, the increased M-L motion of the COM during obstacle crossing showed a positive correlation with an increased M-L range of motion of the swing foot trajectory. This increase in M-L motion indicates a compensatory adjustment in the swing foot trajectory to land the swing foot at an appropriate location that would establish a new base of support to counter the balance disturbance in the frontal plane.

Aged↗
PubMed1999

Kinematic analysis of obstacle clearance during locomotion.

This study investigated the effect of obstacles of different heights on the locomotion of 15 healthy subjects. The following parameters were studied: (1) the distance of the toe and heel markers from the obstacle during toe-off and heel contact, respectively, (2) the minimum clearance distance of the toe and heel markers, and (3) the angular displacements and velocities of the hip, knee, and ankle. Results show significant differences in joint angular kinematics and clearance distances as obstacle height increased. The kinematic and distance differences exhibited both strong linear and non-linear trends. Toe-off distance and heel contact distance did not change significantly with changes in obstacle height.

Adult↗
PubMed1991

Visual control of locomotion: strategies for changing direction and for going over obstacles.

Dynamics of gait adjustments required to go over obstacles and to alter direction of locomotion when cued visually were assessed through the measurement of ground reaction forces, muscle activity, and kinematics. The time of appearance of obstacles of varying heights, their position within the step cycle, and cue lights for direction change were varied. Direction change must be planned in the previous step to reduce the acceleration of the body center of mass toward the landing foot to 0. The inability of steering within the step cycle is due to the incapacity of muscles to rotate the body and translate it along the mediolateral axes. For obstacle avoidance, Ss systematically manipulated the gait patterns as a function of obstacle height and position and the time available within the ongoing step. Greater supraspinal involvement in control of locomotion is found.

Adult↗
PubMedDate not supplied

Nothing is going to stop me now: obstacles perceived by low-income women as they become self-sufficient.

As low-income women struggle to become self-sufficient, they encounter many obstacles. The literature identifies physical and mental health problems, inadequate childcare, inadequate occupational skills, lack of transportation, criminal histories, and limited educational abilities as major barriers to be overcome in this transition. Qualitative data collected from low-income women attending Innovative Alternatives for Women, an occupational skills and health information training center which was developed and implemented by a nurse, refutes several of the previously identified obstacles. Inadequate childcare and transportation were not seen as barriers to success by the program participants, but were viewed as socially acceptable reasons for not working. Eight obstacles were identified by the program participants as being the real reasons for their lack of success. The identified obstacles included the following: lack of self-esteem, especially relating to school; "bad" relationships with men; lack of support from family and friends; limited life options; lack of training for nonwelfare recipients; lack of quality programs; criminal histories; and fear of success.

Anecdotes as Topic↗
PubMed2003

Distraction affects the performance of obstacle avoidance during walking.

In this study, dual-task interference in obstacle-avoidance tasks during human walking was examined. Ten healthy young adults participated in the experiment. While they were walking on a treadmill, an obstacle suddenly fell on the treadmill in front of their left leg during either midswing, early stance, or late stance of the ipsilateral leg. Participants were instructed to avoid the obstacle, both as a single task and while they were concurrently performing a cognitive secondary task (dual task). Rates of failure, avoidance strategy, and a number of kinematic parameters were studied under both task conditions. When only a short response time was available, rates of failure on the avoidance task were larger during the dual task than during the single task. Smaller crossing swing velocities were found during the dual task as compared with those observed in the single task. The difference in crossing swing velocities was attributable to increased stiffness of the crossing swing limb. The results of the present study indicated that divided attention affects young and healthy individuals' obstacle-avoidance performance during walking.

Adult↗
PubMed1989

Wheelchair obstacle course performance in right cerebral vascular accident victims.

The initial experiment of this paper investigated the role of hemispatial neglect in wheelchair-related accidents of right-hemisphere stroke victims. Twelve subjects with and 12 subjects without neglect of left space drove their wheelchairs through an obstacle course. Two types of obstacle course errors were evaluated: direct hits and sideswipes. The neglecting group made significantly more direct hits but there were no significant differences between groups in sideswipe errors. In Experiment 2, the nonneglecting group's data were compared with a left-hemisphere stroke group without neglect and three motor control groups to investigate if their errors resulted from motor deficits. The right-hemisphere stroke group made significantly more left-sided errors and errors in contralateral space than any other group. In Experiment 3, 13 subjects with neglect were taught to scan to the left which resulted in significant decreases in direct hits but not in sideswipes on the obstacle course. These results suggest that obstacle course performance is sensitive to more than hemispatial neglect.

Accident Proneness↗
PubMed1988

Obstacles to effective professional education programming by a voluntary health association: findings from a national survey.

The American Cancer Society (ACS) conducted a nationally representative survey of ACS professional education committee volunteer chairpersons and ACS staff responsible for professional education programs in Divisions and Units of the Society. The survey questionnaire included a set of 25 items (15 in the chairperson questionnaires) representing potential obstacles to effective professional education programming. Subjects rated these obstacles on a four-point scale indicating the extent to which they were perceived as problems in professional education. The survey identified which potential obstacles to professional education programming by a voluntary health association were considered to be most problematic. These included competition from other providers of oncology professional education, outdated audiovisuals and publications, and the recruitment and retention of physician volunteers. The survey verified that there were differences within the organizational structure of the association. In particular, small Units of the Society faced more problems than did Divisions and large Units. The survey found differences in perceived problems between volunteers and staff, particularly in that staff found outdated audiovisuals and publications to be more of a problem than did chairpersons. In general, however, there was a commonality of opinion among all respondents as to which obstacles posed more of a problem than others in professional education.

American Cancer Society↗
PubMed2004

Free surface Hele-Shaw flows around an obstacle: A random walk simulation.

This paper presents computer simulations of pressure driven viscous flows that creep in two dimensions (Hele-Shaw cells). We model the time and spatial evolution of free liquid-gas interfaces perturbed by solid obstacles of various configurations such as wedges, steps, and ellipses. Our goal is to study short- and long-scale obstacle effects on the interface shape and velocity. Specific focus is given to the dynamics of a triple (gas-liquid-solid) contact line, which determines local wetting of obstacles. As a principal contribution, we derive a functional relationship between the contact line velocity and the obstacle geometry.

Journal Article↗
PubMed2005

Two-dimensional flow of foam around an obstacle: force measurements.

A Stokes experiment for foams is proposed. It consists of a two-dimensional flow of a foam, confined between a water subphase and a top plate, around a fixed circular obstacle. We present systematic measurements of the drag exerted by the flowing foam on the obstacle versus various separately controlled parameters: flow rate, bubble volume, bulk viscosity, obstacle size, shape, and boundary conditions. We separate the drag into two contributions: an elastic one (yield drag) at vanishing flow rate and a fluid one (viscous coefficient) increasing with flow rate. We quantify the influence of each control parameter on the drag. The results exhibit in particular a power-law dependence of the drag as a function of the bulk viscosity and the flow rate with two different exponents. Moreover, we show that the drag decreases with bubble size and increases proportionally to the obstacle size. We quantify the effect of shape through a dimensional drag coefficient, and we show that the effect of boundary conditions is small.

Journal Article↗
PubMed1994

A logical state model of circus movement atrial flutter role of anatomic obstacles, anisotropic conduction and slow conduction zones on induction, sustenance, and overdrive paced modulation of reentrant circuits.

Mapping studies of atrial flutter in both the canine sterile pericarditis model and the right atrial enlargement model commonly reveal single loop reentrant circuits in the lower posterior part of the right atrium. Functional bidirectional conduction block and natural anatomical obstacles comprise the central obstacle for reentrant impulse during circus movement atrial flutter. Because the relative roles of anatomical obstacles, in combination with functional barriers, anisotropic conduction, and slow conduction can not be readily assessed with current electrophysiological techniques, an atrial activation model was developed to study the mechanisms of circus movement atrial flutter. A discrete state model consisting of 4096 logically connected cardiac elements was used to simulate atrial activation; an inexcitable region simulating the inferior vena cava (IVC) was also incorporated in the model. Atrial flutter was induced by programmed premature stimulation. Anisotropic conduction velocity properties, regional variations in slow conduction, regional refractory gradients and stimulation parameters were specified for each simulation. The reentrant circuit generally consisted of a single reentrant impulse which circulated around a continuous line of functional bidirectional conduction block joined to the IVC. Rapid pacing, 5-30 ms shorter than the spontaneous reentrant cycle length, was applied to entrain and/or terminate the rhythm. The results of this study demonstrate that patterns of initiation, entrainment, termination and reinitiation of circus movement atrial flutter mimic results from in vivo activation mapping studies. We find that sustained circus movement atrial flutter circuits depend on: 1) natural anatomical obstacles to stabilize reentrant circuits, and 2) anisotropic conduction properties to reduce the degree of functional conduction block needed to maintain circus movement. Rapid pacing of simulated circus movement atrial flutter demonstrated that the entrainment criteria can be satisfied in a two-dimensional syncytium.

Animals↗