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Biomedical subjects

Stephen R Lord

Publications and source records attributed to Stephen R Lord.

At least 37 records · Page 2Linked to original sources
PubMed2005

The beneficial effects of group-based exercises on fall risk profile and physical activity persist 1 year postintervention in older women with low bone mass: follow-up after withdrawal of exercise.

OBJECTIVES: To determine whether exercise-induced reductions in fall risk are maintained in older women 1 year after the cessation of three types of interventions--resistance training, agility training, and general stretching. DESIGN: One-year observational study. SETTING: Community. PARTICIPANTS: Ninety-eight women aged 75 to 85 with low bone mass. MEASUREMENTS: Primary outcome measure was fall risk, measured using the Physiological Profile Assessment tool. Secondary outcome measures were current physical activity level, assessed using the Physical Activity Scale for the Elderly, and formal exercise participation, assessed using an interview. RESULTS: At the end of the follow-up, the fall risk of former participants of all three exercise programs was maintained (i.e., still reduced) from trial completion. Mean fall risk value at the end of follow-up was 43.3% lower than mean baseline value in former participants of the resistance-training group, 40.1% lower in the agility-training group, and 37.4% lower in the general stretching group. Physical activity levels were also maintained from trial completion. Specifically, there was a 3.8% increase in physical activity from baseline for the resistance-training group, a 29.2% increase for the agility-training group, and a 37.7% increase for the general stretching group. CONCLUSION: After three types of group-based exercise programs, benefits are sustained for at least 12 months without further formal exercise intervention. Thus, these 6-month exercise interventions appeared to act as a catalyst for increasing physical activity with resultant reductions in fall risk profile that were maintained for at least 18 months in older women with low bone mass.

Accidental Falls↗
PubMed2005

Gait instability in older people with hallux valgus.

BACKGROUND: Hallux valgus is a common condition that may lead to considerable pain and disability. There is also evidence that hallux valgus may impair balance and increase the risk of falling in older people. Although a number of plantar pressure studies have been undertaken in people with and without hallux valgus, little is known about how hallux valgus affects basic gait patterns or the movement of the upper body when walking. METHODS: Measurements of temporospatial parameters of gait and acceleration patterns of the head and pelvis were obtained in 71 people (24 men, 47 women) between 75 and 93 (mean 80 +/- 4) years of age when walking on both a level surface and a specially designed irregular walkway. Foot problems, vision, peripheral sensation, strength, and reaction time also were evaluated. RESULTS: After adjusting for potential confounders, subjects with moderate to severe hallux valgus were found to exhibit significantly reduced velocity and step length on both walking surfaces and less rhythmic acceleration patterns in the vertical plane when walking on the irregular surface compared to subjects with no or mild hallux valgus. CONCLUSION: These findings indicate that hallux valgus has a significant detrimental impact on gait patterns that may contribute to instability and risk of falling in older people, particularly when walking on irregular terrain.

Accidental Falls↗
PubMed2005

Reliability of simple portable tests of physical performance in older people after hip fracture.

OBJECTIVE: To investigate the test-retest reliability of measures of strength, balance, gait and functional performance when used with older people following hip fracture. SUBJECTS: Thirty people (16 hospital inpatients and 14 community dwellers). DESIGN: Subjects underwent two assessments: one day apart for the hospital inpatients and one week apart for the community dwellers. MEASUREMENT: Strength (dynamometer, sphygmomanometer, spring balance, lateral step-up ability), balance (sway-meter, Functional Reach Test, single leg stance time, Step Test), gait (timed 6-m walk with steps taken, base of support and step length), and functional performance (PPME total score and timed supine-to-sit and sit-to-stand) were measured. RESULTS: Eleven of the 14 continuously scaled measurement tools achieved excellent reliability (intraclass correlation coefficient (ICC) > 0.75) for one or more tests. A hand-held dynamometer was found to be the tool with the highest test-retest reliability for measuring hip muscle strength (ICC (3,1) 0.86 for affected hip abduction). For measurement of knee extension strength, a spring balance (ICC (3,1) 0.94 affected leg) was the most reliable. For testing balance, the Step Test (ICC (3,1) 0.94 for stepping with affected leg) and Functional Reach Test (ICC (3,1) 0.89) had the highest test-retest reliability. The ICC (3,1) values were 0.97 for walking velocity (comfortable pace) and 0.96 for the total score of the Physical Performance and Mobility Examination. CONCLUSION: The test-retest reliability of a number of simple measures of physical performance is excellent when used with this population.

Aged↗
PubMed2004

Incidence of hip fracture in New South Wales: are our efforts having an effect?

OBJECTIVE: To examine trends in hospital admission for hip fracture in New South Wales between July 1990 and June 2000. DESIGN: Analysis of routinely collected hospital separation data. SETTING: Public and private acute-care hospitals in NSW. PARTICIPANTS: Admissions of patients aged 50 years and over with a primary diagnosis of fracture of the neck of femur (International classification of diseases, 9th revision [ICD-9] code 820 or ICD-10 codes S72.0-S72.2). MAIN OUTCOME MEASURES: Number and rates of hospital admission for fracture of the neck of femur per 1000 population; inpatient mortality rates per 1000 admissions. RESULTS: Between July 1990 and June 2000, the number of admissions to NSW acute-care hospitals for hip fracture increased by 41.9% in men (from 1059 to 1503 per year) and by 31.2% in women (from 3160 to 4145 per year). However, age-specific and age-adjusted rates remained practically unchanged. The average length of stay for admissions for hip fracture decreased significantly from 19.2 days (95% CI, 18.5-19.8 days) in 1990-1991 to 14.2 days (95% CI, 13.8-14.6 days) in 1999-2000. No significant change was observed in the overall inpatient death rates per 1000 admissions. CONCLUSIONS: The findings support recent reports that the increase in hip fracture rates during most of the past century may have ended. However, the number of admissions for hip fracture is still rising. Preventive measures to reduce the burden of this condition on the healthcare system and community need to be pursued and strengthened.

Age Distribution↗
PubMed2004

Walking stability and sensorimotor function in older people with diabetic peripheral neuropathy.

OBJECTIVE: To evaluate, in older people with diabetic peripheral neuropathy (DPN) and in age-matched controls, acceleration patterns of the head and pelvis when walking to determine the effect of lower-limb sensory loss on walking stability. DESIGN: Case-control study. SETTING: Falls and balance laboratory in Australia. PARTICIPANTS: Thirty persons with diabetes mellitus (age range, 55-91 y) and 30 age-matched controls. INTERVENTIONS: Acceleration patterns of the head and pelvis were measured while participants walked on a level surface and an irregular walkway. Participants also underwent tests of vision, sensation, strength, reaction time, and balance. MAIN OUTCOME MEASURES: Temporospatial gait parameters and variables derived from acceleration signals. RESULTS: Participants with DPN had reduced walking speed, cadence, and step length, and less rhythmic acceleration patterns at the head and pelvis compared with controls. These differences were particularly evident when participants walked on the irregular surface. Participants with DPN also had impaired peripheral sensation, reaction time, and balance. CONCLUSIONS: Older people with DPN have an impaired ability to stabilize their body when walking on irregular surfaces, even if they adopt a more conservative gait pattern. These results provide further insights into the role of peripheral sensory input in the control of gait stability, and suggest possible mechanisms underlying the increased risk of falling in older people with diabetic neuropathy.

Acceleration↗
PubMed2004

A randomized controlled trial of weight-bearing versus non-weight-bearing exercise for improving physical ability after usual care for hip fracture.

OBJECTIVE: To compare the effects of weight-bearing and non-weight-bearing home exercise programs and a control program on physical ability (strength, balance, gait, functional performance) in older people who have had a hip fracture. DESIGN: Randomized controlled trial with 4-month follow-up. SETTING: Australian community-dwellers (82%) and residents of aged care facilities who had completed usual care after a fall-related hip fracture. PARTICIPANTS: One hundred twenty older people entered the trial, 40 per group (average age +/- standard deviation, 79+/-9y) and 90% completed the 4-month retest. INTERVENTION: Home exercise prescribed by a physical therapist. MAIN OUTCOME MEASURES: Strength, balance, gait, and functional performance. RESULTS: At the 4-month retest, there were differences between the groups in the extent of improvement since the initial assessment for balance (F(10,196)=2.82, P<.001) and functional performance (F(6,200)=3.57, P<.001), but not for strength (F(12,190)=1.09, P=.37) or gait (F(8,200)=.39, P=.92). The weight-bearing exercise group showed the greatest improvements in measures of balance and functional performance (between-group differences of 30%-40% of initial values). CONCLUSIONS: A weight-bearing home exercise program can improve balance and functional ability to a greater extent than a non-weight-bearing program or no intervention among older people who have completed usual care after a fall-related hip fracture.

Activities of Daily Living↗
PubMed2004

Reliability of the GAITRite walkway system for the quantification of temporo-spatial parameters of gait in young and older people.

The purpose of this study was to evaluate the test-retest reliability of an instrumented walkway system (the GAITRite mat) for the measurement of temporal and spatial parameters of gait in young and older people. Thirty young subjects (12 males, 18 females) aged between 22 and 40 years (mean 28.5, S.D. 4.8) and 31 older subjects (13 males, 18 females) aged between 76 and 87 years (mean 80.8, S.D. 3.1) walked at a self-selected comfortable walking speed across the pressure-sensor mat three times and repeated the process approximately 2 weeks later. Intra-class correlation coefficients (ICC), coefficients of variation (CV) and 95% limits of agreement were then determined. For both groups of subjects, the reliability of walking speed, cadence and step length was excellent (ICCs between 0.82 and 0.92 and CVs between 1.4 and 3.5%). Base of support and toe in/out angles, although exhibiting high ICCs, were associated with higher CVs (8.3-17.7% in young subjects and 14.3-33.0% in older subjects). It is concluded that the GAITRite mat exhibits excellent reliability for most temporo-spatial gait parameters in both young and older subjects, however, base of support and toe in/out angles need to viewed with some caution, particularly in older people.

Adult↗
PubMed2004

Resistance and agility training reduce fall risk in women aged 75 to 85 with low bone mass: a 6-month randomized, controlled trial.

OBJECTIVES: To compare the effectiveness of group resistance and agility-training programs in reducing fall risk in community-dwelling older women with low bone mass. DESIGN: A randomized, controlled, single-blind 25-week prospective study with assessments at baseline, midpoint, and trial completion. SETTING: Community center. PARTICIPANTS: Community-dwelling women aged 75 to 85 with low bone mass. INTERVENTION: Participants were randomly assigned to one of three groups: resistance training (n=32), agility training (n=34), and stretching (sham) exercises (n=32). The exercise classes for each study arm were held twice weekly. MEASUREMENTS: The primary outcome measure was fall risk (derived from weighted scores from tests of postural sway, reaction time, strength, proprioception, and vision), as measured using a Physiological Profile Assessment (PPA). Secondary outcome measures were ankle dorsiflexion strength, foot reaction time, and Community Balance and Mobility Scale score. RESULTS: Attendance at the exercise sessions for all three groups was excellent: resistance training (85.4%), agility training (87.3%), and stretching program (78.8%). At the end of the trial, PPA fall-risk scores were reduced by 57.3% and 47.5% in the resistance and agility-training groups, respectively, but by only 20.2% in the stretching group. In the resistance and agility groups, the reduction in fall risk was mediated primarily by improved postural stability, where sway was reduced by 30.6% and 29.2%, respectively. There were no significant differences between the groups for the secondary outcomes measures. Within the resistance-training group, reductions in sway were significantly associated with improved strength, as assessed using increased squat load used in the exercise sessions. CONCLUSION: These findings support the implementation of community-based resistance and agility-training programs to reduce fall risk in older women with low bone mass. Such programs may have particular public health benefits because it has been shown that this group is at increased risk of falling and sustaining fall-related fractures.

Absorptiometry, Photon↗
PubMed2004

A pilot study of long-term monitoring of human movements in the home using accelerometry.

We assessed the feasibility of using a waist-mounted, wireless triaxial accelerometer (TA) to monitor human movements in an unsupervised home setting to detect changes in functional status. A pilot study was carried out with six healthy subjects aged 80-86 years. The subjects wore a TA unit every day for two to three months. Each morning they carried out a short routine of directed movements that included standing, sitting, lying and walking. Important movement variables were measured. During the rest of the day, subjects were monitored for falls, and variables such as metabolic energy expenditure were measured. All subjects remained healthy; there was no overall change in functional status and there were only slight fluctuations in health status. No longitudinal changes were detected in any of the variables measured during the directed routine. There was a moderate correlation between weekly self-reported health status and energy expenditure: subjects reported a lower health status for weeks in which they expended less energy. The TA system was found to be practical for long-term, unsupervised home monitoring. All subjects found the system simple to use and the TA unit unobtrusive and comfortable to wear. High compliance rates were achieved: the TA units were worn on 88% of the days in the study, for an average of 11.2 hours per day.

Acceleration↗
PubMed2004

Physiological risk factors for falls in older people with lower limb arthritis.

OBJECTIVE: To investigate physiological risk factors for falls in people with self-reported lower limb arthritis. METHODS: Six hundred eighty-four community-dwelling men and women aged 75-98 years (mean 80.0, SD 4.4), categorized with and without lower limb arthritis, underwent quantitative tests of strength, peripheral sensation, vision, reaction time, balance, and pain. A 12-month history of falls was also obtained. RESULTS: Subjects with self-reported lower extremity arthritis performed significantly worse in tests of knee and ankle muscular strength, lower limb proprioception, postural sway, and leaning balance than subjects without lower extremity arthritis, while being comparable in vision, tactile sensitivity, and reaction time. This pattern of specific impairments was also evident when group results for the arthritis subjects were compared with community normative values and presented as a physiological profile. The arthritis group suffered significantly more falls [relative risk (RR) 1.22, 95% CI 1.03-1.46] and injurious falls (RR 1.27, 95% CI 1.01-1.60) in the previous 12 months than the nonarthritis group. Within the arthritis group, reduced knee extension strength and increased sway were identified as significant predictors of falls. CONCLUSION: Older people with lower limb arthritis are at increased risk of falling due to deficits in neuromuscular systems. A physiological falls-risk profile based on mean test scores for the arthritis group highlights deficits in muscular strength, knee proprioception, and standing balance, indicating the need for targeted falls prevention interventions for this population.

Accidental Falls↗
PubMed2003

A randomised trial of weight-bearing versus non-weight-bearing exercise for improving physical ability in inpatients after hip fracture.

The purpose of this study was to assess the effects of weight-bearing and non-weight-bearing exercise on strength, balance, gait and functional performance among older inpatients following hip fracture. Eighty people (mean age 81 years, SD 8) undergoing inpatient rehabilitation after fall-related hip fracture were randomised to receive two-week programs of either weight-bearing or non-weight-bearing exercise prescribed by a physiotherapist. Both groups improved markedly (in the order of 50%) on measures of physical ability. Overall there was little difference between groups in the extent of improvement, however post hoc testing identified some additional strength benefits for the non-weight-bearing group--non-affected leg hip flexion mean difference in extent of improvement was 9.3 N (95% CI 3.7 to 15.0), non-affected leg hip abduction mean difference in extent of improvement was 6.5 N (95% CI 0.1 to 12.9). There were also additional functional benefits for the weight-bearing group--improved ability to complete a lateral step-up on the affected leg with nil or one hand supports (OR 3.4, 95% CI 1.1 to 12.3) and the need for less supportive walking aids (p = 0.045). Weight-bearing and non-weight-bearing exercise programs produce similar effects on strength, balance, gait and functional performance among inpatients soon after hip fracture.

Accidental Falls↗
PubMed2003

Acceleration patterns of the head and pelvis when walking on level and irregular surfaces.

The aim of this study was to evaluate acceleration patterns at the head and pelvis while subjects walked on a level and an irregular walking surface, to develop an understanding of how the postural control system responds to challenging walking conditions. Thirty young, healthy subjects walked on a level corridor and on artificial grass underlain with foam and wooden blocks placed in an arbitrary manner. Temporo-spatial gait parameters and acceleration patterns at the head and pelvis were measured. The results revealed that when walking on the irregular surface, subjects were able to maintain their velocity, but adopted a slower and more variable cadence and a significantly longer stride length. The magnitude of pelvis accelerations increased, however head accelerations were not affected by the walking surface. When considered as an overall pattern of movement, these findings suggest that one of the primary objectives of the postural control system when walking on irregular surfaces is head control, and that subjects adapt their stepping pattern on irregular surfaces to ensure that the head remains stable.

Acceleration↗
PubMed2003

Differing risk factors for falls in nursing home and intermediate-care residents who can and cannot stand unaided.

OBJECTIVES: To determine fall risk factors in nursing home and intermediate-care residents who can and cannot stand unaided. DESIGN: Prospective cohort study. SETTING: Residential elderly care facilities in Sydney, Australia. PARTICIPANTS: One thousand people aged 65 to 103 (mean age +/- standard deviation: 85.0 +/- 7.4). MEASUREMENTS: Accidental falls. RESULTS: Fall rates were highest in those with fair standing balance, intermediate in those with the best standing balance, and lowest in those with the worst standing balance. This nonlinear pattern was even more striking when subjects were categorized according to their standing balance and ability to rise from a chair. Using this dual classification, fall rates were highest in those who could rise from a chair but could not stand unaided (81%) and lowest in those who could neither rise from a chair nor stand unaided (48%). In residents who could stand unaided, risk factors included increased age, male sex, higher care classifications, incontinence, psychoactive medication use, previous falls, and slow reaction times. In contrast, quite different risk factors were evident in residents who could not stand unaided, with a number of known fall risk factors (previous stroke, reduced ability to rise from a chair, slow reaction times) being associated with fewer falls. In this group, risk factors were intermediate versus nursing home care, poor health status, psychoactive medication use, Parkinson's disease, previous falls, and being able to get out of a chair. CONCLUSION: The findings indicate that there are different risk factors for falls for people living in residential aged care facilities who can and cannot stand unaided. These findings provide important information for developing fall-prevention strategies and suggest that those who can stand unaided but have multiple falls risk factors constitute the highest priority group for such interventions.

Accidental Falls↗
PubMed2003

The effect of group exercise on physical functioning and falls in frail older people living in retirement villages: a randomized, controlled trial.

OBJECTIVES: To determine whether a 12-month program of group exercise can improve physical functioning and reduce the rate of falling in frail older people. DESIGN: Cluster randomized, controlled trial of 12 months duration. SETTING: Retirement villages in Sydney and Wollongong, Australia. PARTICIPANTS: Five hundred fifty-one people aged 62 to 95 (mean+/-standard deviation=79.5+/-6.4) who were living in self- and intermediate-care retirement villages. MEASUREMENTS: Accidental falls, choice stepping reaction time, 6-minute walk distance postural sway, leaning balance, simple reaction time, and lower-limb muscle strength. RESULTS: Two hundred eighty subjects were randomized to the weight-bearing group exercise (GE) intervention that was designed to improve the ability of subjects to undertake activities for daily living. Subjects randomized to the control arm (n=271) attended flexibility and relaxation (FR) classes (n=90) or did not participate in a group activity (n=181). In spite of the reduced precision of cluster randomization, there were few differences in the baseline characteristics of the GE and combined control (CC) subjects, although the mean age of the GE group was higher than that of the CC group, and there were fewer men in the GE group. The mean number of classes attended was 39.4+/-28.7 for the GE subjects and 31.5+/-25.2 for the FR subjects. After adjusting for age and sex, there were 22% fewer falls during the trial in the GE group than in the CC group (incident rate ratio=0.78, 95% confidence interval (CI)=0.62-0.99), and 31% fewer falls in the 173 subjects who had fallen in the past year (incident rate ratio=0.69, 95% CI=0.48-0.99). At 6-month retest, the GE group performed significantly better than the CC group in tests of choice stepping reaction time, 6-minute walking distance, and simple reaction time requiring a hand press. The groups did not differ at retest in tests of strength, sway, or leaning balance. CONCLUSION: These findings show that group exercise can prevent falls and maintain physical functioning in frail older people.

Accidental Falls↗
PubMed2003

Age-related differences in walking stability.

BACKGROUND: a large proportion of falls in older people occur when walking; however the mechanisms underlying impaired balance during gait are poorly understood. OBJECTIVE: to evaluate acceleration patterns at the head and pelvis in young and older subjects when walking on a level and an irregular walking surface, in order to develop an understanding of how ageing affects postural responses to challenging walking conditions. METHODS: temporo-spatial gait parameters and variables derived from acceleration signals were recorded in 30 young people aged 22-39 years (mean 29.0, SD 4.3), and 30 older people with a low risk of falling aged 75-85 years (mean 79.0, SD 3.0) while walking on a level and an irregular walking surface. Subjects also underwent tests of vision, sensation, strength, reaction time and balance. RESULTS: older subjects exhibited a more conservative gait pattern, characterised by reduced velocity, shorter step length and increased step timing variability. These differences were particularly pronounced when walking on the irregular surface. The magnitude of accelerations at the head and pelvis were generally smaller in older subjects; however the smoothness of the acceleration signals did not differ between the two groups. Older subjects performed worse on tests of vision, peripheral sensation, strength, reaction time and balance. CONCLUSION: the adoption of a more conservative basic gait pattern by older people with a low risk of falling reduces the magnitude of accelerations experienced by the head and pelvis when walking, which is likely to be a compensatory strategy to maintain balance in the presence of age-related deficits in physiological function, particularly reduced lower limb strength.

Acceleration↗
PubMed2003

Community-based group exercise improves balance and reduces falls in at-risk older people: a randomised controlled trial.

BACKGROUND: recent studies have found that moderate intensity exercise is an effective intervention strategy for preventing falls in older people. However, research is required to determine whether supervised group exercise programmes, conducted in community settings with at-risk older people referred by their health care practitioner are also effective in improving physical functioning and preventing falls in this group. OBJECTIVES: to determine whether participation in a weekly group exercise programme with ancillary home exercises over one year improves balance, muscle strength, reaction time, physical functioning, health status and prevents falls in at-risk community-dwelling older people. METHODS: the sample comprised 163 people aged over 65 years identified as at risk of falling using a standardised assessment screen by their general practitioner or hospital-based physiotherapist, residing in South Western Sydney, Australia. Subjects were randomised into either an exercise intervention group or a control group. Physical performance and general health measures were assessed at baseline and repeated 6-months into the trial. Falls were measured over a 12-month follow-up period using monthly postal surveys. RESULTS: at baseline both groups were well matched in their physical performance, health and activity levels. The intervention subjects attended a median of 23 exercise classes over the year, and most undertook the home exercise sessions at least weekly. At retest, the exercise group performed significantly better than the controls in three of six balance measures; postural sway on the floor with eyes open and eyes closed and coordinated stability. The groups did not differ at retest in measures of strength, reaction time and walking speed or on Short-Form 36, Physical Activity Scale for the Elderly or fear of falling scales. Within the 12-month trial period, the rate of falls in the intervention group was 40% lower than that of the control group (IRR=0.60, 95% CI 0.36-0.99). CONCLUSIONS: these findings indicate that participation in a weekly group exercise programme with ancillary home exercises can improve balance and reduce the rate of falling in at-risk community dwelling older people.

Accidental Falls↗
PubMed2003

Acceleration patterns of the head and pelvis when walking are associated with risk of falling in community-dwelling older people.

BACKGROUND: A large proportion of falls in older people occur when walking, however the mechanisms underlying impaired balance during gait are poorly understood. This study evaluated acceleration patterns of the head and pelvis when walking on a level and an unpredictably irregular surface to determine whether older people at risk of falling demonstrate an impaired ability to stabilize the body under challenging conditions. METHODS: One hundred community-dwelling older people aged between 75 and 93 years were evaluated for their risk of falling using a range of physiological tests previously found to be accurate predictors of falling in prospective studies. Temporo-spatial gait parameters and acceleration patterns at the head and pelvis were then measured in three orthogonal planes while subjects walked on a flat corridor and an unpredictably irregular walkway. Harmonic ratios of head and pelvis accelerations in each plane were calculated to provide an indicator of stability. RESULTS: Subjects with a high risk of falling exhibited reduced temporo-spatial gait parameters and increased step timing variability. Harmonic ratios of acceleration patterns were reduced at the head and pelvis in the vertical and antero-posterior directions. These differences were particularly evident when walking on the irregular surface. CONCLUSION: Older people at risk of falling adopt a more conservative basic walking pattern, but this does not ensure that the movements of the head and pelvis are stable. The irregular pelvis and head accelerations evident in the high risk group suggests that these subjects may have difficulty controlling trunk motion and maintaining a stable visual field when walking, particularly on irregular terrain.

Acceleration↗