What is the influence of severity levels of knee osteoarthritis on gait initiation?

BackgroundThe anticipatory postural adjustments required for gait initiation have not yet been investigated in older adults with different levels of severity of knee osteoarthritis. This study aimed to evaluate the anticipatory postural adjustments adopted by older adults with different severity levels of knee osteoarthritis during gait initiation.MethodsSixty-seven older adults with knee osteoarthritis (mild, moderate, and severe levels) and 11 healthy older adults control were evaluated bilaterally with a force plate to analyze gait initiation. The center of pressure trajectory during gait initiation was divided into four phases: three anticipatory postural adjustments, and a locomotor phase. The length, duration, and velocity of each phase were calculated.FindingsThe results showed that during the right and left limbs swing forward, the severe and moderate knee osteoarthritis groups presented a significant reduction in the length of anticipatory postural adjustment phases, locomotion, duration, and velocity (P < 0.05). The severe knee osteoarthritis group presented a significantly higher body mass index (P < 0.003) than the other groups. However, just the healthy group presented a correlation between body mass index and anticipatory postural adjustments.InterpretationOur results demonstrated that older adults with severe and moderate levels of knee osteoarthritis adopt longer lasting and slower anticipatory postural adjustment phases, lower locomotion, and lower center of pressure displacement during gait initiation, suggesting that this population has adaptive strategy in performing gait initiation, which is significantly changed by the knee osteoarthritis severity level.     

The influence of Tai Chi training on the center of pressure trajectory during gait initiation in older adults

OBJECTIVE: To determine if a program of intense Tai Chi exercise that has been shown to reduce the risk of falling in older adults improves postural control by altering the center of pressure (COP) trajectory during gait initiation. DESIGN: Before-after trial. SETTING: Biomechanics research laboratory. PARTICIPANTS: Twenty-eight older adults transitioning to frailty who participated in either a 48-week intervention of intense Tai Chi training or a wellness education (WE) program. INTERVENTIONS: Eight Tai Chi forms emphasizing trunk rotation, weight shifting, coordination, and narrowing of lower-extremity stance were taught twice weekly. WE program participants met once a week and received lectures focused on health.Main outcome measures The COP was recorded during gait initiation both before and after the 48-week intervention by using a forceplate sampling at 300 Hz. The COP trajectory was divided into 3 periods (S1, S2, S3) by identifying 2 landmark events. Displacement and average velocity of the COP trace in the anteroposterior (x) and mediolateral (y) directions, as well as smoothness, were calculated. RESULTS: Tai Chi training increased the posterior displacement of the COP during S1 and improved the smoothness of the COP during S2. CONCLUSIONS: Tai Chi improved the mechanism by which forward momentum is generated and improved coordination during gait initiation, suggesting improvements in postural control.     

The influence of stimulus cue on the initiation of stepping in young and older adults

OBJECTIVES: To investigate the influence of different reaction stimulus cues on the characteristics of ground reaction forces during the initiation of rapid forward stepping, and to determine whether age-related differences in step initiation are influenced by the type of stimulus cue used to trigger stepping. DESIGN: Case-control study. SETTING: University-based research laboratory. PARTICIPANTS: Fifteen healthy younger adults and 35 community-dwelling older adult volunteers. MAIN OUTCOME MEASURES: Subjects performed forward step initiation in response to 3 different reaction stimulus cues (light, sound, electrocutaneous) during simple reaction-time conditions. Ground reaction force data were collected and used to characterize the timing and magnitude features of the postural (weight-transfer) and step components. RESULTS: In comparison with the light and sound stimuli, the nonnoxious electrocutaneous trigger cue was associated with an increase in the magnitude of the initial displacement of the center of pressure (COP) in the mediolateral direction. Overall, older subjects were slower to initiate the postural and step components, and displayed a reduction in the initial posterior displacement of the COP. CONCLUSIONS: The postural component for lateral weight transfer was augmented by the electrocutaneous trigger cue, suggesting its potential to enhance step initiation among clinical populations. Age-related changes in stepping were unaffected by the type of stimulus cue, but the older group had a slower response initiation time and less forward propulsion. The abilities of many older persons may be compromised in situations where rapid adjustments in the base of support through stepping are triggered by environmental stimuli.     

Investigating the anticipatory postural adjustment phase of gait initiation in different directions in chronic ankle instability patients

Objective

The main objective of the present study was to analyze how supra spinal motor control mechanisms are altered in different directions during anticipatory postural phase of gait initiation in chronic ankle instability patients. It seems that supra spinal pathways modulate anticipatory postural adjustment phase of gait initiation. Yet, there is a dearth of research on the effect of chronic ankle instability on the anticipatory postural adjustment phase of gait initiation in different directions.

Gait initiation in community-dwelling adults with Parkinson disease: comparison with older and younger adults without the disease

BACKGROUND AND PURPOSE: Initiation of gait requires transitions from relatively stationary positions to stability with movement and from double- to single-limb stances. These are deliberately destabilizing activities that may be difficult for people with early Parkinson disease (PD), even when they have no problems with level walking. We studied differences in postural stability during gait initiation between participants with early and middle stages of PD (characterized by Hoehn and Yahr as stages 1-3) and 2 other groups of participants without PD--older and younger adults. SUBJECTS: The mean ages of the 3 groups of participants were as follows: subjects with PD, 69.3 years (SD=5.7, range=59-78); older subjects without PD, 69.0 years (SD=3.9, range=65-79); and younger subjects without PD, 27.5 (SD=3.9, range=22-35). METHODS: A 3-dimensional motion analysis system was used with 2 force platforms to obtain data for center of mass (COM) and center of pressure (COP). The distance between the vertical projections of the COM and the COP (COM-COP distance) was used to reflect postural control during 5 events in gait initiation. RESULTS: By use of multivariate analysis of variance, differences in COM-COP distance were found among the 3 groups. An analysis of variance indicated differences for 4 of the 5 events in gait initiation. A Scheffe post hoc analysis demonstrated differences in gait initiation between the subjects with PD and both groups of subjects without PD (2 events) and between the subjects with PD and the younger subjects without PD (2 events). DISCUSSION AND CONCLUSION: The COM-COP distance relationship was used to measure postural control during the transition from quiet standing to steady-state gait. Differences between groups indicated that individuals with impaired postural control allow less COM-COP distance than do individuals with no known neurologic problems. The method used could prove useful in the development and assessment of interventions to improve ambulation safety and enhance the independence of people with impaired postural control.     

Walking more slowly than with normal velocity: The influence on trunk and pelvis kinematics in young and older healthy persons

Background

Few studies have addressed trunk and pelvis movements during gait, although they play an important role in gait control. The aim of this study was to compare trunk and pelvis kinematics between slower walking (1, 2, 3, 4 kmph) and normal walking (5 kmph), and between healthy adults who were young (n = 15, 20–30 years) and older (n = 17, 50–60 years).

Methods

After 4 min of treadmill walking, the 3-dimensional trunk and pelvis kinematics was measured (Polhemus Liberty™, 250 Hz). A repeated measures ANOVA with simple contrasts was used to look for differences between the velocity conditions of walking and independent t-testing for comparison between the age groups (significance level: 5%, SPSS20).

Findings

Walking more slowly than with normal velocity induces (1) a decrease in vertical center of mass of the trunk displacement, trunk lateral flexion and axial rotation and pelvis lateral and antero-posterior tilting, and (2) an increase in lateral and antero-posterior center of mass of the trunk displacement. Compared to young persons, older persons show: (1) larger pelvis axial rotations and trunk lateral and antero-posterior movements, and (2) smaller pelvis lateral tilting and trunk vertical movements and rotations.

Interpretation

The literature reports that patients often walk slowly and that older persons show different gait patterns compared to young persons. This study shows that there are changes in trunk and pelvis kinematics (1) when walking more slowly than with normal velocity and (2) in older persons compared to young persons. These data could be taken into account in gait rehabilitation.     

Kinematic effects of different gait speeds during gait initiation movement

[Purpose] We investigated the influence of gait speed on the movement strategy during gait initiation. [Participants and Methods] This study included 21 young healthy individuals (11 males and 10 females; mean age, 21.7 ± 0.5 years; mean height, 166.1 ± 9.8 cm; and mean weight, 57.3 ± 11.2 kg). A three-dimensional motion analyzer and strain gauge force platform were used in this study. The measurement task consisted of gait initiation from the quiet stance; the two measurement conditions were normal gait and the highest speed. The analysis interval was from the start of the center of pressure migration to the heel contact at the first step of the swing limb. The center of gravity, center of pressure, joint movements, step length, and step time during the anticipatory postural control (from the start of center of pressure migration to swing leg-heel off) and swing (swing leg-heel off to swing leg-heel contact) phases were analyzed. [Results] Significant differences were observed in the center of gravity, center of pressure, hip flexion, abduction movement, stance-limb ankle dorsiflexion movement during the anticipatory postural control phase, and step time during the anticipatory postural control and swing phases. The stance-limb ankle plantar flexion movement and step length did not differ significantly in the swing phase. [Conclusion] When the gait speed increases, fluctuations in the joint movements increase as the center of pressure displacement increases, thus requiring complex control.     

Effects of Parkinson's disease and levodopa on functional limits of stability

BACKGROUND: The voluntary, maximum inclined posture reflects the self-perceived limits of stability. Parkinson's disease is associated with small, bradykinetic postural weight shifts while standing but it is unclear whether this is due to reduced limits of stability and/or to the selection of abnormal strategies for leaning. The aim of this study was to investigate the effects of Parkinson's disease and levodopa medication on voluntary limits of stability and strategies used to reach these limits. METHODS: Fourteen subjects with Parkinson's disease (OFF and ON levodopa) and 10 age-matched controls participated in the study. Functional limits of stability were quantified as the maximum center of pressure excursion during voluntary forward and backward leaning. Postural strategies to achieve functional limits of stability were assessed by (i) body segments alignment, (ii) the difference between center of pressure and center of mass in preparation for a lean, (iii) the timing and the velocity of the preparation phase. FINDINGS: Functional limits of stability were significantly smaller in subjects with Parkinson's disease compared to control subjects. Subjects with Parkinson's disease maintained their stooped posture while leaning, initiated leaning with a smaller difference between center of pressure and center of mass and had a slower leaning velocity compared to control subjects. Levodopa enlarged the limits of stability in subjects with Parkinson's disease because of an increase in maximum forward, but not backward leans, but did not significantly improve postural alignment, preparation for a leaning movement, or velocity of leaning. INTERPRETATION: Parkinson's disease reduces functional limits of stability as well as the magnitude and velocity of postural preparation during voluntary, forward and backward leaning while standing. Levodopa improves the limits of stability but not the postural strategies used to achieve the leaning.     

Gait initiation and lateral wedge insole for individuals with early knee osteoarthritis

BackgroundPeople with knee osteoarthritis are at higher risk of postural deficits and locomotor adaptations which could be manifested in transient tasks like gait initiation. To better understand the effect of early knee osteoarthritis on gait initiation, we measured the gait initiation in two groups of early knee osteoarthritis and healthy age-matched controls and assessed the effect of lateral wedge insole in knee osteoarthritis group.MethodsTwenty-one individuals with early knee osteoarthritis, mean (SD) age = 53.1 (7.4, years), and 19 age- and sex-matched asymptomatic healthy individuals, mean (SD) age = 47.5 (11.2, years), participated. Centre of pressure trajectories were used to quantify the two phases of gait initiation in barefoot condition: anticipatory postural adjustment, and locomotor phase. The immediate and four-week effect of lateral wedge insole and shod condition were also compared for individuals in knee osteoarthritis group.FindingsLonger duration of anticipatory postural adjustment phase (P = 0.046), locomotor phase (P = 0.049), and total duration of gait initiation (P = 0.035) with lower length and velocity of the center of pressure trajectories in anticipatory postural adjustment phase (P = 0.002, and 0.008, respectively) were observed in knee osteoarthritis group compared to controls. Lateral wedge insole could increase the length and velocity of the centre of pressure in locomotor phase compared to barefoot condition (P = 0.001, and 0.002, respectively).InterpretationOur study outlined that people with early knee osteoarthritis adopt different gait initiation strategies mainly in postural preparation phase. The potential effect of lateral wedge insole was shown with better performance of the locomotor phase.Clinical trial registry numberIRCT2016060628310N1.     

Resistance training and gait function in patients with Parkinson's disease

OBJECTIVE: To determine whether patients with Parkinson's disease who are enrolled in a resistance training program can gain strength similar to that of normal control subjects and whether these gains in strength would improve their gait function. DESIGN: Subjects included 14 patients with mild-to-moderate Parkinson's disease of either gender and six normal control subjects of similar age. The training consisted of an 8-wk course of resistance training twice per week, focused primarily on the lower limbs. The primary outcome measures consisted of exercise performance monitoring and quantitative gait analysis before and after the training course. RESULTS: Both the patients with Parkinson's disease and normal control subjects significantly increased their performance with resistance training. Subjects with Parkinson's disease had gains in strength similar to those of normal elderly adults. Patients with Parkinson's disease also had significant gains in stride length, walking velocity, and postural angles compared with pretreatment values. CONCLUSIONS: Patients with mild-to-moderate Parkinson's disease can obtain increases in performance or strength similar to that of normal adults of the same age in a resistance training program. Resistance training can produce functional improvements in gait and may, therefore, be useful as part of a physical rehabilitation and/or health maintenance program for patients with Parkinson's disease.     

Gait initiation and dynamic balance control in Parkinson's disease

OBJECTIVE: To determine whether the magnitude of the separation between the center of pressure (COP) and the whole-body center of mass (COM) during gait initiation can differentiate patients with varying severity of Parkinson's disease (PD) disability. DESIGN: Cross-sectional, intact groups research design. SETTING: Biomechanics research laboratory. PARTICIPANTS: Forty-three patients were stratified into 2 groups based on the Hoehn and Yahr (H&Y) disability score, which heavily favors balance in determining disability. The 2 groups were: H&Y score of 2.0 or less (n=23; age, 61+/-10y) or H&Y score of 2.5 or higher (n=20; age, 70+/-9y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The peak COP-COM distance represents the maximum separation between the location of the whole-body COM and the ground reaction force's COP, and thus is an indicator of dynamic balance control. The peak COP-COM was evaluated during 3 phases of the COP trajectory during a gait initiation task. RESULTS: The peak magnitude of the COP-COM distance was significantly greater during the end of the single-support phase in the less disabled patients (H&Y score or=2.5) (P=.004). CONCLUSIONS: The differences in COP-COM distances between these H&Y groups suggest that patients with PD who have impaired postural control produce shorter COM-COP distances than do persons without clinically detectable balance impairment. This method of evaluation could prove a useful quantitative index to examine the impact of interventions designed to improve ambulation and balance in PD.     

Does the impaired postural control in Parkinson's disease affect the habituation to non-sequential external perturbation trials?

BackgroundHow people with Parkinson's disease habituate their postural response to unpredictable translation perturbation is not totally understood. We compared the capacity to change the postural responses after unexpected external perturbation and investigated the habituation plateaus of postural responses to non-sequential perturbation trials in people with Parkinson's disease and healthy older adults.MethodsIn people with Parkinson's disease (n = 37) and older adults (n = 20), sudden posterior support-surface translational were applied in 7 out of 17 randomized trials to ensure perturbation unpredictability. Electromyography and center of pressure parameters of postural response were analyzed by ANOVAs (Group vs. Trials). Two simple planned contrasts were performed to determine at which trial the responses first significantly habituate, and by which trials the habituation plateaus.FindingsOlder adults demonstrated a first response change in trial 5 and habituation plateaus after trial 4, while for people with Parkinson's disease, the first change occurred in trial 2 and habituation plateau after trial 5 observed by center of pressure range. People with Parkinson's disease demonstrated a greater center of pressure range in trial 1 compared to older adults. Independent of trial, people with Parkinson's disease vs. older adults demonstrated a greater ankle muscle co-activation and recovery time.InterpretationDespite the greater center of pressure range in the first trial, people with Parkinson's disease can habituate to unpredictable perturbations. This is reflected by little, to no difference in the time-course of adaptation for all but 2 parameters that showed only marginal differences between people with Parkinson's disease and older adults.     

Impact of age and obstacle negotiation on timing measures of gait initiation

Introduction

The separate and combined impacts of age and walkway obstruction on reaction time, anticipatory postural adjustment phases of gait initiation and cognitive dual task performance are not well understood. This study aimed to a) examine the impact of age and task complexity on reaction and anticipatory postural adjustment phases separately b) examine the impact of age and walkway obstruction on cognitive task performance while walking.

Young and older adults use different strategies to perform a standing turning task

Background

Falls are the leading cause of death in adults over 65 years of age. Falls during turning are likely to result in costly and debilitating hip fractures. Two-thirds of adults who fracture a hip will never regain their previous level of independence. The purpose of this study, therefore, was to examine performance of turning in place in young and older adults.

Methods

Ten young (mean age = 25 years) and 10 community-dwelling older adults (mean age = 75 years) performed a standing turning task under two conditions: feet constrained and feet unconstrained. Dependent measures were rotational range of motion of the head-on-trunk, trunk-on-pelvis, pelvis and feet; trunk flexion/extension and knee flexion; and center of pressure range and center of mass range in both the anterior–posterior and medial–lateral directions.

Findings

In both conditions, older adults used less head-on-trunk but more trunk-on-pelvis rotation than the young adults. In the constrained condition, older adults also used more trunk extension and knee flexion than the young adults. In the unconstrained condition, more of the older adults moved their feet (60% vs. 30% of young adults). These differences in segmental motion resulted in greater center of mass movement for the older adults in the constrained but not the unconstrained foot condition.

Interpretations

Older adults show changes in segmental spinal range of motion associated with postural instability while turning in place. Foot movements play an essential role in compensating for these changes and maintaining postural stability.     

Interlimb coordination is impaired during walking in persons with Parkinson's disease

Background

Coordination between the upper and lower extremities is important to providing dynamic stability during human gait. Though limited, previous research has suggested that interlimb coordination may be impaired in persons with Parkinson's disease. We extend this previous work using continuous analytical techniques to enhance our understanding of interlimb coordination during gait in persons with Parkinson's disease.

Methods

Eighteen adults with Parkinson's disease and fifteen healthy older adults walked overground while undergoing three-dimensional motion capture. Ipsilateral and contralateral interlimb coordination between the sagittal shoulder and hip angles was assessed using cross-covariance techniques. Independent samples and paired samples t-tests compared measures of interlimb coordination between groups and between sides within the participants with Parkinson's disease, respectively. Pearson's correlations were applied to investigate associations between interlimb coordination measures and subscores of gait, posture, and bradykinesia on the Unified Parkinson's Disease Rating Scale.

Findings

Ipsilateral and contralateral interlimb coordination was reduced in persons with Parkinson's disease compared to the healthy older adults. Ipsilateral coordination between the upper and lower extremities more affected by disease was found to be negatively associated with clinical scores of gait and posture. Interlimb coordination was not significantly associated with clinical measures of bradykinesia.

Interpretation

Persons with Parkinson's disease exhibit reduced interlimb coordination during gait when compared to healthy older adults. These reductions in coordination are related to clinically-meaningful worsening of gait and posture in persons with PD and coordination of arm and leg movements should be considered in future research on gait therapy in this population.     

Voluntary sway and rapid orthogonal transitions of voluntary sway in young adults,and low and high fall-risk older adults

Background

Falls amongst older people have been linked to reduced postural stability and slowed movement responses. The objective of this study was to examine differences in postural stability and the speed of response between young adults, low fall-risk older adults, and high fall-risk older adults during voluntary postural sway movements.

Methods

Twenty-five young adults (25 ± 4 years), and 32 low fall-risk (74 ± 5 years), and 16 high fall-risk (79 ± 7 years) older adults performed voluntary sway and rapid orthogonal transitions of voluntary sway between the anterior–posterior and medial–lateral directions. Measures included reaction and movement time and the amplitudes of the centre of pressure, centre of mass, and the separation distance between the centre of pressure and centre of mass.

Findings

Both fall-risk groups compared to the young had slower reaction and movement time, greater centre of pressure and/or centre of mass amplitude in the orthogonal (non-target) direction during voluntary sway, and reduced anterior–posterior and medial–lateral separation between the centre of pressure and centre of mass during voluntary sway and orthogonal transitions. High compared to low fall-risk individuals had slower reaction and movement time, increased non-target centre of mass amplitude during voluntary sway, and reduced medial–lateral centre of pressure and centre of mass separation during voluntary sway and orthogonal transitions.

Interpretation

Age-related deterioration of postural control resulted in slower reactive responses and reduced control of the direction of body movement during voluntary sway and orthogonal transitions. Slower postural reaction and movement time and reduced medial–lateral control of the centre of mass during voluntary sway movements are associated with increased fall-risk in community-living older people.     

Adaptation of postural recovery responses to a vestibular sensory illusion in individuals with Parkinson disease and healthy controls

BackgroundThe ability to adapt postural responses to sensory illusions diminishes with age and is further impaired by Parkinson disease. However, limited information exists regarding training-related adaptions of sensory reweighting in these populations.MethodsThis study sought to determine whether Parkinson disease or age would differentially affect acute postural recovery or adaptive postural responses to novel or repeated exposure to sensory illusions using galvanic vestibular stimulation during quiet stance.FindingsAcutely, individuals with Parkinson disease demonstrated larger center of pressure coefficient of variation compared to controls. Unlike individuals with Parkinson disease and asymptomatic older adults, healthy young adults acutely demonstrated a reduction in Sample Entropy to the sensory illusion. Following a period of consolidation Sample Entropy increased in the healthy young group, which coincided with a decreased center of pressure coefficient of variation. Similar changes were not observed in the Parkinson disease or older adult groups.InterpretationTaken together, these results suggest that young adults learn to adapt to vestibular illusion in a more robust manner than older adults or those with Parkinson disease. Further investigation into the nature of this adaptive difference is warranted.     

Frailty assessment of older adults,first-time applicants of public home care service in Norway

ObjectiveEarly detection of frailty is essential to prevent or delay disability. The most appropriate screening tool for frailty among home-dwelling older adults is under debate. The present study estimates the prevalence of frailty among older adults, first-time applicants of public home care service in Norway, and investigates the appropriateness of gait speed and Short Physical Performance Battery as screening-tools for frailty.Design and settingWe conducted a cross-sectional study of 116 older adults >65 years applying for public home care service for the first time. Frailty was assessed by an adapted version of the Fried Frailty Phenotype. The test accuracies of gait speed and Short Physical Performance Battery to detect frailty were calculated for a general population >70 years in Norway.Results62.1% of the participants were frail, 29.3% were prefrail, and 8.6% were robust. Mean gait speed and Short Physical Performance Battery-scores were significantly lower in frail compared to prefrail individuals, and significantly lower in prefrail compared to robust individuals. The sensitivity and specificity of gait speed at a cut point of 0.8 m/s to detect physical frailty phenotype was 99% and 68%, respectively.Conclusions The high prevalence of frailty in the present study indicates that screening for frailty should be considered at an earlier time point than when older adults apply for public home care service for the first time. Gait speed may be an appropriate screening tool for frailty in a general population >70 years in Norway.

KEY POINTS

• The prevalence of frailty among older adults, first-time applicants of public home care services in Norway is major.
• Screening for frailty should be considered before older adults apply for public home care service for the first time.
• Gait speed at a cut point at 0.8 m/s may be an appropriate screening tool for frailty in a general population >70 years in Norway.

     

Dimensions of physical frailty and cognitive function in older adults with amnestic mild cognitive impairment

ObjectiveThe objective of this study was to examine relationships between dimensions of physical frailty and severity of cognitive impairment in older adults with amnestic mild cognitive impairment (aMCI).Patients and methodsThe prevalence of physical frailty dimensions including slow gait speed, low physical activity, and low grip strength was examined among 201 sedentary older adults with aMCI. Associations between dimensions of physical frailty and severity of cognitive impairment, as measured with the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and individual dimensions of cognitive function were examined using multiple linear regression models.ResultsGreater than 50% of participants met physical frailty criteria on dimensions of slow gait speed, low physical activity and low grip strength. Slower gait speed was associated with elevated severity of cognitive impairment. Both gait speed and physical activity were associated with individual dimensions cognitive function.ConclusionsDimensions of physical frailty, particularly gait speed, were associated with severity of cognitive impairment, after adjusting for age, sex and age-related factors. Further studies are needed to investigate mechanisms and early intervention strategies that assist older adults with aMCI to maintain function and independence.     

Recruiting and screening older, transitional to frail adults in congregate living facilities.

Historically older adults have been recruited from the community or from long-term care facilities. The research study, The Effects of Intense Tai Chi Training in the Older Adult, targeted adults 70 years and older who were residing in congregate living facilities and transitioning to frailty according to the Speechley/Tinetti scale. This article describes the strategies that were designed and implemented to recruit and screen the 287 older adults who entered the randomized, single-blinded clinical trial.