Change in body fat mass is independently associated with executive functions in older women: a secondary analysis of a 12-month randomized controlled trial

OBJECTIVES

To investigate the independent contribution of change in sub-total body fat and lean mass to cognitive performance, specifically the executive processes of selective attention and conflict resolution, in community-dwelling older women.

METHODS

This secondary analysis included 114 women aged 65 to 75 years old. Participants were randomly allocated to once-weekly resistance training, twice-weekly resistance training, or twice-weekly balance and tone training. The primary outcome measure was the executive processes of selective attention and conflict resolution as assessed by the Stroop Test. Sub-total body fat and lean mass were measured by dual-energy x-ray absorptiometry (DXA) to determine the independent association of change in both sub-total body fat and sub-total body lean mass with Stroop Test performance at trial completion.

RESULTS

A multiple linear regression model showed reductions in sub-total body fat mass to be independently associated with better performance on the Stroop Test at trial completion after accounting for baseline Stroop performance, age, baseline global cognitive state, baseline number of comorbidities, baseline depression, and experimental group. The total variance explained was 39.5%; change in sub-total body fat mass explained 3.9% of the variance. Change in sub-total body lean mass was not independently associated with Stroop Test performance (P>0.05).

CONCLUSION

Our findings suggest that reductions in sub-total body fat mass - not sub-total lean mass - is associated with better performance of selective attention and conflict resolution.

The association between cognitive function and white matter lesion location in older adults: a systematic review

Background

Maintaining cognitive function is essential for healthy aging and to function autonomously within society. White matter lesions (WMLs) are associated with reduced cognitive function in older adults. However, whether their anatomical location moderates these associations is not well-established. This review systematically evaluates peer-reviewed evidence on the role of anatomical location in the association between WMLs and cognitive function.

Methods

In accordance with the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement, databases of EMBASE, PUBMED, MEDLINE, and CINAHL, and reference lists of selected papers were searched. We limited our search results to adults aged 60 years and older, and studies published in the English language from 2000 to 2011. Studies that investigated the association between cognitive function and WML location were included. Two independent reviewers extracted: 1) study characteristics including sample size, sample characteristic, and study design; 2) WML outcomes including WML location, WML quantification method (scoring or volume measurement), strength of the MRI magnet in Tesla, and MRI sequence used for WML detection; and 3) cognitive function outcomes including cognitive tests for two cognitive domains of memory and executive function/processing speed.

Results

Of the 14 studies included, seven compared the association of subcortical versus periventricular WMLs with cognitive function. Seven other studies investigated the association between WMLs in specific brain regions (e.g., frontal, parietal lobes) and cognitive function. Overall, the results show that a greater number of studies have found an association between periventricular WMLs and executive function/processing speed, than subcortical WMLs. However, whether WMLs in different brain regions have a differential effect on cognitive function remains unclear.

Conclusions

Evidence suggests that periventricular WMLs may have a significant negative impact on cognitive abilities of older adults. This finding may be influenced by study heterogeneity in: 1) MRI sequences, WML quantification methods, and neuropsychological batteries; 2) modifying effect of cardiovascular risk factors; and 3) quality of studies and lack of sample size calculation.

Exploration of the association between quality of life, assessed by the EQ-5D and ICECAP-O, and falls risk, cognitive function and daily function, in older adults with mobility impairments

Background

Our research sought to understand how falls risk, cognitive function, and daily function are associated with health related quality of life (using the EuroQol-5D) and quality of life (using the ICECAP-O) among older adults with mobility impairments.

Methods

The EQ-5D and ICECAP-O were administered at 12 months post first clinic attendance at the Vancouver Falls Prevention Clinic. We report descriptive statistics for all baseline characteristics collected at first clinic visit and primary outcomes of interest. Using multivariate stepwise linear regression, we assessed the construct validity of the EQ-5D and ICECAP-O using three dependent measures that are recognized indicators of “impaired mobility” – physiological falls risk, general balance and mobility, and cognitive status among older adults.

Results

We report data on 215 seniors who attended the Vancouver Falls Prevention Clinic and received their first clinic assessment. Patients had a mean age of 79.3 (6.2) years. After accounting for known covariates (i.e., age and sex), the ICECAP-O domains explained a greater amount of variation in each of the three dependent measures compared with the EQ-5D domains.

Conclusion

Both the EQ-5D and ICECAP-O demonstrate associations with falls risk and general balance and mobility; however, only the ICECAP-O was associated with cognitive status among older adults with mobility impairments.

Trial registration

ClinicalTrials.gov Identifier: NCT01022866

Examining the relationship between specific cognitive processes and falls risk in older adults: a systematic review

This systematic review aims to establish which cognitive domains are associated with falls or falls risk. Recent evidence suggests that impaired cognition increases seniors' risk of falling. The purpose of this review was to identify the cognitive domains that are significantly associated with falls or falls risk in older adults. We conducted a systematic review of peer-reviewed journal articles published from 1948 to present, focusing on studies investigating different domains of cognitive function and their association with falls or falls risk in adults aged 60 years or older. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we completed a comprehensive search of MEDLINE, PubMed, and EMBASE databases to identify studies examining the association between cognitive function and falls or falls risk. With an expert in the field, we developed a quality assessment questionnaire to rate the quality of the studies included in this systematic review. Twenty-five studies were included in the review. We categorized studies based on two related but distinct cognitive domains: (1) executive functions or (2) dual-task ability. Twelve studies reported a significant association between executive functions and falls risk. Thirteen studies reported that dual-task performance is a predictor of falls or falls risk in older adults. Three studies did not report an association between cognition and falls risk. Consistent evidence demonstrated that executive functions and dual-task performance were highly associated with falls or falls risk. The results from this review will aid healthcare professionals and researchers in developing innovative screening and treatment strategies for mitigating falls risk by targeting specific cognitive domains.

SF-6D and EQ-5D result in widely divergent incremental cost-effectiveness ratios in a clinical trial of older women: implications for health policy decisions

SUMMARY

Using two instruments (SF-6D and EQ-5D) to estimate quality adjusted life years (QALYs), we conducted an economic evaluation of a 12-month randomized controlled trial with a 12-month follow-up study in older women to evaluate the value for money of two doses of resistance training compared with balance and tone classes. We found that the incremental QALYs estimated from the SF-6D were two- to threefold greater than those estimated from the EQ-5D.

INTRODUCTION

Decision makers must continually choose between existing and new interventions. Hence, economic evaluations are increasingly prevalent. The impact of quality-adjusted life year (QALY) estimates using different instruments on the incremental cost-effectiveness ratios (ICERs) is not well understood in older adults. Thus, we compared ICERs, in older women, estimated by the EuroQol-5D (EQ-5D) and the Short Form-6D (SF-6D) to discuss implications on decision making.

METHODS

Using both the EQ-5D and the SF-6D, we compared the incremental cost per QALY gained in a randomized controlled trial of resistance training in 155 community-dwelling women aged 65 to 75 years. The 12-month randomized controlled trial included a subsequent 12-month follow-up. Our focus, the follow-up study, included 123 of the 155 participants from the Brain Power study; 98 took part in the economic evaluation (twice-weekly balance and tone exercises, n = 28; once-weekly resistance training, n = 35; twice-weekly resistance training, n = 35). Our primary outcome measure was the incremental cost per QALY gained of once- or twice-weekly resistance training compared with balance and tone exercises.

RESULTS

At cessation of the follow-up study, the incremental QALY was -0.051 (EQ-5D) and -0.144 (SF-6D) for the once-weekly resistance training group and -0.081 (EQ-5D) and -0.127 (SF-6D) for the twice-weekly resistance training group compared with balance and tone classes.

CONCLUSION

The incremental QALYs estimated from the SF-6D were two- to threefold greater than those estimated from the EQ-5D. Given the large magnitude of difference, the choice of preference-based utility instrument may substantially impact health care decisions.

Self-efficacy is independently associated with brain volume in older women

BACKGROUND

ageing is highly associated with neurodegeneration and atrophy of the brain. Evidence suggests that personality variables are risk factors for reduced brain volume. We examine whether falls-related self-efficacy is independently associated with brain volume.

METHOD

a cross-sectional analysis of whether falls-related self-efficacy is independently associated with brain volumes (total, grey and white matter). Three multivariate regression models were constructed. Covariates included in the models were age, global cognition, systolic blood pressure, functional comorbidity index and current physical activity level. MRI scans were acquired from 79 community-dwelling senior women aged 65-75 years old. Falls-related self-efficacy was assessed by the activities-specific balance confidence (ABC) scale.

RESULTS

after accounting for covariates, falls-related self-efficacy was independently associated with both total brain volume and total grey matter volume. The final model for total brain volume accounted for 17% of the variance, with the ABC score accounting for 8%. For total grey matter volume, the final model accounted for 24% of the variance, with the ABC score accounting for 10%.

CONCLUSION

we provide novel evidence that falls-related self-efficacy, a modifiable risk factor for healthy ageing, is positively associated with total brain volume and total grey matter volume.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00426881.

A comparison of the ICECAP-O with EQ-5D in a falls prevention clinical setting: are they complements or substitutes?

PURPOSE

Our research explored whether two preference-based outcome measures (EuroQol EQ-5D and ICECAP-O) are complements or substitutes in the context of the Vancouver Falls Prevention Clinic for seniors.

METHODS

The EQ-5D and ICECAP-O were administered once at 12 months post first clinic attendance. We report descriptive statistics for all baseline characteristics collected at first clinic visit and primary outcomes of interest. We ascertain feasibility by reporting item completion rates for the EQ-5D and ICECAP-O. Contingency tables for a priori assertions between the ICECAP-O and EQ-5D were used to demonstrate whether unique or similar aspects of benefit were captured. We used exploratory factor analysis, to ascertain the number of unique underlying latent factors associated with the attributes assessed by the EQ-5D and ICECAP-O.

RESULTS

We report data on 215 seniors who attended the Vancouver Falls Prevention Clinic who had a mean age of 79.3 (6.2) years. The item completion rate was 99 % for the EQ-5D and 92 % for the ICECAP-O. The two contingency tables detailed few discrepancies. The results of the exploratory factor analysis indicate that the two instruments are tapping into distinct factors that are complementary.

CONCLUSION

Our study suggests that the EQ-5D and ICECAP-O provide complementary information.

A comparison of the ICECAP-O with EQ-5D in a falls prevention clinical setting: are they complements or substitutes?

PURPOSE

Our research explored whether two preference-based outcome measures (EuroQol EQ-5D and ICECAP-O) are complements or substitutes in the context of the Vancouver Falls Prevention Clinic for seniors.

METHODS

The EQ-5D and ICECAP-O were administered once at 12 months post first clinic attendance. We report descriptive statistics for all baseline characteristics collected at first clinic visit and primary outcomes of interest. We ascertain feasibility by reporting item completion rates for the EQ-5D and ICECAP-O. Contingency tables for a priori assertions between the ICECAP-O and EQ-5D were used to demonstrate whether unique or similar aspects of benefit were captured. We used exploratory factor analysis, to ascertain the number of unique underlying latent factors associated with the attributes assessed by the EQ-5D and ICECAP-O.

RESULTS

We report data on 215 seniors who attended the Vancouver Falls Prevention Clinic who had a mean age of 79.3 (6.2) years. The item completion rate was 99 % for the EQ-5D and 92 % for the ICECAP-O. The two contingency tables detailed few discrepancies. The results of the exploratory factor analysis indicate that the two instruments are tapping into distinct factors that are complementary.

CONCLUSION

Our study suggests that the EQ-5D and ICECAP-O provide complementary information.

Emerging concept: 'central benefit model' of exercise in falls prevention

Falls are a common geriatric syndrome and are the third leading cause of chonic disability worldwide. Falls are not random events and occur, at least in part, due to impaired physiological function, such as impaired balance, and cognitive impairment. The clinical syndrome of falls is important for Sports and Exercise Medicine Clinicians as there is Level 1 evidence that targeted exercise prescription is an effective intervention strategy. The widely accepted dogma is that improved physical function, balance and muscle strength, underlies the effectiveness of the exercise in reducing falls. However, findings from randomised controlled trials suggest that exercise reduce falls via mechanisms other than improved physiological function. The authors propose that improved cognitive function - specifically, executive functions - and associated functional plasticity may be an important yet underappreciated mechanism by which the exercise reduces falls in older adults.

Functional neural correlates of reduced physiological falls risk

Background

It is currently unclear whether the function of brain regions associated with executive cognitive processing are independently associated with reduced physiological falls risk. If these are related, it would suggest that the development of interventions targeted at improving executive neurocognitive function would be an effective new approach for reducing physiological falls risk in seniors.

Methods

We performed a secondary analysis of 73 community-dwelling senior women aged 65 to 75 years old who participated in a 12-month randomized controlled trial of resistance training. Functional MRI data were acquired while participants performed a modified Eriksen Flanker Task - a task of selective attention and conflict resolution. Brain volumes were obtained using MRI. Falls risk was assessed using the Physiological Profile Assessment (PPA).

Results

After accounting for baseline age, experimental group, baseline PPA score, and total baseline white matter brain volume, baseline activation in the left frontal orbital cortex extending towards the insula was negatively associated with reduced physiological falls risk over the 12-month period. In contrast, baseline activation in the paracingulate gyrus extending towards the anterior cingulate gyrus was positively associated with reduced physiological falls risk.

Conclusions

Baseline activation levels of brain regions underlying response inhibition and selective attention were independently associated with reduced physiological falls risk. This suggests that falls prevention strategies may be facilitated by incorporating intervention components - such as aerobic exercise - that are specifically designed to induce neurocognitive plasticity.

Trial Registration

ClinicalTrials.gov Identifier: NCT00426881

Sustained economic benefits of resistance training in community-dwelling senior women

To determine whether the health and cost benefits of resistance training were sustained 12 months after formal cessation of the intervention.

DESIGN

Cost-utility analysis conducted alongside a randomized controlled trial.

SETTING

Community-dwelling women aged 65 to 75 living in Vancouver, British Columbia.

PARTICIPANTS

One hundred twenty-three of the 155 community-dwelling women aged 65 to 75 years who originally were randomly allocated to once-weekly resistance training (n=54), twice-weekly resistance training (n=52), or twice-weekly balance and tone exercises (control group; n=49) participated in the 12-month follow-up study. Of these, 98 took part in the economic evaluation (twice-weekly balance and tone exercises, n=28; once-weekly resistance training, n=35; twice-weekly resistance training, n=35).

MEASUREMENTS

The primary outcome measure was incremental cost per quality-adjusted life year (QALY) gained. Healthcare resource utilization was assessed over 21 months (2009 prices); health status was assessed using the EuroQol-5D to calculate QALYs using a 21-month time horizon.

RESULTS

Once- and twice-weekly resistance training were less costly than balance and tone classes, with incremental mean healthcare costs of Canadian dollars (CAD$)1,857 and CAD$1,077, respectively. The incremental QALYs for once- and twice-weekly resistance training were -0.051 and -0.081, respectively, compared with balance and tone exercises.

CONCLUSION

The cost benefits of participating in a 12-month resistance training intervention were sustained for the once- and twice-weekly resistance training group, whereas the health benefits were not.

Economic evaluation of dose-response resistance training in older women: a cost-effectiveness and cost-utility analysis

SUMMARY

We estimated the incremental cost-effectiveness of a once-weekly or twice-weekly resistance training intervention compared with balance and tone classes in terms of falls prevented and quality-adjusted life years (QALYs) gained. Both resistance training interventions were more likely to save health care resource money and offer better health outcomes for falls prevention than balance and tone classes.

INTRODUCTION

This study aims to estimate the incremental cost-effectiveness and cost-utility of a once-weekly or twice-weekly resistance training intervention compared with twice-weekly balance and tone classes in terms of falls prevented and QALYs gained.

METHODS

Economic evaluation was conducted concurrently with a three-arm randomized controlled trial including 155 community-dwelling women aged 65 to 75 years, Mini Mental State Examination ≥24, and visual acuity 20/40 or better. Participants received the once-weekly resistance training (n = 54), the twice-weekly resistance training (n = 51) or the twice-weekly balance and tone (the comparator) classes (n = 50) for 1 year. Measurements included the number of falls for each participant, healthcare resource utilization, and associated costs over 9 months; health status was assessed using the EQ-5D and SF-6D to calculate QALYs.

RESULTS

Based on the point estimates from our base case analysis, we found that both once- and twice-weekly resistance training groups were less costly (p < 0.05) and more effective than twice-weekly balance and tone classes. The incremental QALYs assessed using the SF-6D were 0.003 for both the once- and twice-weekly resistance training groups, compared with the twice-weekly balance and tone classes. The incremental QALYs assessed using the EQ-5D were 0.084 for the once-weekly and 0.179 for the twice-weekly resistance training groups, respectively, compared with the twice-weekly balance and tone classes.

CONCLUSIONS

An individually tailored resistance training intervention delivered once or twice weekly provided better value for money for falls prevention than balance and tone classes.

Exercise, brain, and cognition across the life span

This is a brief review of current evidence for the relationships between physical activity and exercise and the brain and cognition throughout the life span in non-pathological populations. We focus on the effects of both aerobic and resistance training and provide a brief overview of potential neurobiological mechanisms derived from non-human animal models. Whereas research has focused primarily on the benefits of aerobic exercise in youth and young adult populations, there is growing evidence that both aerobic and resistance training are important for maintaining cognitive and brain health in old age. Finally, in these contexts, we point out gaps in the literature and future directions that will help advance the field of exercise neuroscience, including more studies that explicitly examine the effect of exercise type and intensity on cognition, the brain, and clinically significant outcomes. There is also a need for human neuroimaging studies to adopt a more unified multi-modal framework and for greater interaction between human and animal models of exercise effects on brain and cognition across the life span.

Does a home-based strength and balance programme in people aged > or =80 years provide the best value for money to prevent falls? A systematic review of economic evaluations of falls prevention interventions

OBJECTIVES

To investigate the value for money of strategies to prevent falls in older adults living in the community.

DESIGN

Systematic review of peer reviewed journal articles reporting an economic evaluation of a falls prevention intervention as part of a randomised controlled trial or a controlled trial, or using an analytical model. MEDLINE, PUBMED, EMBASE and NHS EED databases were searched to identify cost-effectiveness, cost-utility and cost-benefit studies from 1945 through July 2008.

MAIN OUTCOME MEASURES

The primary outcome measure was incremental cost-effectiveness, cost-utility and cost-benefit ratios in the reported currency and in pounds sterling at 2008 prices. The quality of the studies was assessed using two instruments: (1) an economic evaluation checklist developed by Drummond and colleagues and (2) the Quality of Health Economic Studies instrument.

RESULTS

Nine studies meeting our inclusion criteria included eight cost-effectiveness analyses, one cost-utility and one cost-benefit analysis. Three effective falls prevention strategies were cost saving in a subgroup of

PARTICIPANTS

(1) an individually customised multifactorial programme in those with four or more of the eight targeted fall risk factors, (2) the home-based Otago Exercise Programme in people > or =80 years and (3) a home safety programme in the subgroup with a previous fall. These three findings were from six studies that scored > or =75% on the Quality of Health Economic Studies instrument.

CONCLUSIONS

Best value for money came from effective single factor interventions such as the Otago Exercise Programme which was cost saving in adults 80 years and older. This programme has broad applicability thus warranting warrants health policy decision-makers' close scrutiny.

International comparison of cost of falls in older adults living in the community: a systematic review

SUMMARY

Our objective was to determine international estimates of the economic burden of falls in older people living in the community. Our systematic review emphasized the need for a consensus on methodology for cost of falls studies to enable more accurate comparisons and subgroup-specific estimates among different countries.

INTRODUCTION

The purpose of this study was to determine international estimates of the economic burden of falls in older people living in the community.

METHODS

This is a systematic review of peer-reviewed journal articles reporting estimates for the cost of falls in people aged > or =60 years living in the community. We searched for papers published between 1945 and December 2008 in MEDLINE, PUBMED, EMBASE, CINAHL, Cochrane Collaboration, and NHS EED databases that identified cost of falls in older adults. We extracted the cost of falls in the reported currency and converted them to US dollars at 2008 prices, cost items measured, perspective, time horizon, and sensitivity analysis. We assessed the quality of the studies using a selection of questions from Drummond's checklist.

RESULTS

Seventeen studies met our inclusion criteria. Studies varied with respect to viewpoint of the analysis, definition of falls, identification of important and relevant cost items, and time horizon. Only two studies reported a sensitivity analysis and only four studies identified the viewpoint of their economic analysis. In the USA, non-fatal and fatal falls cost US $23.3 billion (2008 prices) annually and US $1.6 billion in the UK.

CONCLUSIONS

The economic cost of falls is likely greater than policy makers appreciate. The mean cost of falls was dependent on the denominator used and ranged from US $3,476 per faller to US $10,749 per injurious fall and US $26,483 per fall requiring hospitalization. A consensus on methodology for cost of falls studies would enable more accurate comparisons and subgroup-specific estimates among different countries.

Feasibility of a 6-month exercise and recreation program to improve executive functioning and memory in individuals with chronic stroke

BACKGROUND

Physical activity is beneficial for improving cognitive function in healthy older adults. However, research results on the benefits of physical activity on cognitive performance after stroke are limited.

OBJECTIVE

To determine if a combined exercise and recreation program can improve the executive functioning and memory of individuals with chronic stroke.

METHODS

In all, 11 ambulatory participants with chronic stroke (mean age 67 ± 10.8 years) participated in a 6-month program of exercise for 2 hours and recreation for 1 hour weekly. Executive functions and memory were assessed at baseline and at 3 and 6 months by a battery of standard neuropsychological tests, including response inhibition, cognitive flexibility, dual task (motor plus cognitive), and memory. Motor ability was also assessed. Nonparametric statistics were used to obtain the differences between the 3 assessments.

RESULTS

At baseline, substantial deficits in all aspects of executive functioning were revealed. From baseline to 3 months, the mean improvement was 10% ± 14% for the dual task (Walking While Talking), -3% ± 22% (χ(2) = 2.4; P > .05) for response inhibition (Stroop Test), and 61% ± 69% for memory (Rey Auditory Verbal Learning Test-long delay). From baseline to 6 months, the mean improvement was 7% ± 7.5% for response inhibition (Stroop Test). In addition, knee strength and walking speed improved significantly at 3 months.

CONCLUSIONS

This pilot study suggests that exercise and recreation may improve memory and executive functions of community-dwelling individuals with stroke. Further studies require a larger sample size and a control group.

The independent contribution of executive functions to health related quality of life in older women

Background

Cognition is a multidimensional construct and to our knowledge, no previous studies have examined the independent contribution of specific domains of cognition to health related quality of life. To determine whether executive functions are independently associated with health related quality of life assessed using Quality Adjusted Life Years (QALYs) calculated from the EuroQol EQ-5D (EQ-5D) in older women after adjusting for known covariates, including global cognition. Therefore, we conducted a secondary analysis of community-dwelling older women aged 65-75 years who participated in a 12-month randomized controlled trial of resistance training. We assessed global cognition using the Mini-Mental State Examination (MMSE) and executive functions using the: 1) Stroop Test; 2) Trail Making Test (Part B) and 3) Digits Verbal Span Backwards Test. We calculated QALYs from the EQ-5D administered at baseline, 6 months and 12 months.

Results

Our multivariate linear regression model demonstrated the specific executive processes of set shifting and working memory, as measured by Trail Making Test (Part B) and Digits Verbal Span Backward Test (p < 0.01) respectively, were independently associated with QALYs after accounting for age, comorbidities, general mobility, and global cognition. The final model explained 50% of the variation in QALYs.

Conclusions

Our study highlights the specific executive processes of set shifting and working memory were independently associated with QALYs -- a measure of health related quality of life. Given that executive functions explain variability in QALYs, clinicians may need to consider assessing executive functions when measuring health related quality of life. Further, the EQ-5D may be used to track changes in health status over time and serve as a screening tool for clinicians.

Trial Registration

ClinicalTrials.gov Identifier: NCT00426881.

Resistance training and executive functions: a 12-month randomized controlled trial

BACKGROUND

Cognitive decline among seniors is a pressing health care issue. Specific exercise training may combat cognitive decline. We compared the effect of once-weekly and twice-weekly resistance training with that of twice-weekly balance and tone exercise training on the performance of executive cognitive functions in senior women.

METHODS

In this single-blinded randomized trial, 155 community-dwelling women aged 65 to 75 years living in Vancouver were randomly allocated to once-weekly (n = 54) or twice-weekly (n = 52) resistance training or twice-weekly balance and tone training (control group) (n = 49). The primary outcome measure was performance on the Stroop test, an executive cognitive test of selective attention and conflict resolution. Secondary outcomes of executive cognitive functions included set shifting as measured by the Trail Making Tests (parts A and B) and working memory as assessed by verbal digit span forward and backward tests. Gait speed, muscular function, and whole-brain volume were also secondary outcome measures.

RESULTS

Both resistance training groups significantly improved their performance on the Stroop test compared with those in the balance and tone group (P < or = .03). Task performance improved by 12.6% and 10.9% in the once-weekly and twice-weekly resistance training groups, respectively; it deteriorated by 0.5% in the balance and tone group. Enhanced selective attention and conflict resolution was significantly associated with increased gait speed. Both resistance training groups demonstrated reductions in whole-brain volume compared with the balance and tone group at the end of the study (P < or = .03).

CONCLUSION

Twelve months of once-weekly or twice-weekly resistance training benefited the executive cognitive function of selective attention and conflict resolution among senior women.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00426881.

Dual-task gait performance among community-dwelling senior women: the role of balance confidence and executive functions

BACKGROUND

Exploring factors that contribute to dual-task gait performance among seniors is of particular interest in falls prevention because dual-task-related gait changes are associated with increased falls risk. It is unclear currently which specific executive processes are most relevant to dual-task gait performance and whether "balance confidence" is independently associated with dual-task gait performance.

METHODS

A cross-sectional analysis of 140 senior women aged 65-75 years old. Balance confidence was assessed by the Activities-Specific Balance Confidence scale. Three key executive processes were assessed by standard neuropsychological tests: (i) set shifting, (ii) working memory, and (iii) response inhibition. Dual-task gait performance was assessed by the simple and complex versions of the walking while talking (WWT) test. Two linear regression models were constructed to determine the independent association of executive functions and balance confidence with: (i) simple WWT completion time and (ii) complex WWT completion time.

RESULTS

Balance confidence was independently associated with both simple and complex WWT completion times after accounting for age, time to walk 40 ft without talking, and global cognition. Set shifting was independently associated with complex WWT completion time; no executive processes were independently associated with simple WWT completion time.

CONCLUSIONS

This study highlights that balance confidence is independently associated with dual-task gait performance. Furthermore, executive functions do not play a significant role in dual-task gait performance when the concurrent cognitive load is low. Clinicians may need to consider balance confidence and executive functions in the assessment and rehabilitation of dual-task gait performance among community-dwelling seniors.

Cortical and trabecular bone in the femoral neck both contribute to proximal femur failure load prediction

We examined the contributions of femoral neck cortical and trabecular bone to proximal femur failure load. We found that trabecular bone mineral density explained a significant proportion of variance in failure load after accounting for total bone size and cortical bone mineral content or cortical area.

INTRODUCTION

The relative contribution of femoral neck trabecular and cortical bone to proximal femur failure load is unclear.

OBJECTIVES

Our primary objective was to determine whether trabecular bone mineral density (TbBMD) contributes to proximal femur failure load after accounting for total bone size and cortical bone content. Our secondary objective was to describe regional differences in the relationship among cortical bone, trabecular bone, and failure load within a cross-section of the femoral neck.

MATERIALS AND METHODS

We imaged 36 human cadaveric proximal femora using quantitative computed tomography (QCT). We report total bone area (ToA), cortical area (CoA), cortical bone mineral content (CoBMC), and TbBMD measured in the femoral neck cross-section and eight 45 degrees regions. The femora were loaded to failure.

RESULTS AND OBSERVATIONS

Trabecular bone mineral density explained a significant proportion of variance in failure load after accounting for ToA and then either CoBMC or CoA respectively. CoBMC contributed significantly to failure load in all regions of the femoral neck except the posterior region. TbBMD contributed significantly to failure load in all regions of the femoral neck except the inferoanterior, superoposterior, and the posterior regions.

CONCLUSION

Both cortical and trabecular bone make significant contributions to failure load in ex vivo measures of bone strength.

Exercise and cognition in older adults: is there a role for resistance training programmes?

In recent years, there has been a strong interest in physical activity as a primary behavioural prevention strategy against cognitive decline. A number of large prospective cohort studies have highlighted the protective role of regular physical activity in lowering the risk of cognitive impairment and dementia. Most prospective intervention studies of exercise and cognition to date have focused on aerobic-based exercise training. These studies highlight that aerobic-based exercise training enhances both brain structure and function. However, it has been suggested that other types of exercise training, such as resistance training, may also benefit cognition. The purpose of this brief review is to examine the evidence regarding resistance training and cognitive benefits. Three recent randomised exercise trials involving resistance training among seniors provide evidence that resistance training may have cognitive benefits. Resistance training may prevent cognitive decline among seniors via mechanisms involving insulin-like growth factor I and homocysteine. A side benefit of resistance training, albeit a very important one, is its established role in reducing morbidity among seniors. Resistance training specifically moderates the development of sarcopenia. The multifactorial deleterious sequelae of sarcopenia include increased falls and fracture risk as well as physical disability. Thus, clinicians should consider encouraging their clients to undertake both aerobic-based exercise training and resistance training not only for "physical health" but also because of the almost certain benefits for "brain health".

The effect of group-based exercise on cognitive performance and mood in seniors residing in intermediate care and self-care retirement facilities: a randomised controlled trial

OBJECTIVE

To determine the effect of a general group-based exercise programme on cognitive performance and mood among seniors without dementia living in retirement villages.

DESIGN

Randomised controlled trial.

SETTING

Four intermediate care and four self-care retirement village sites in Sydney, Australia.

PARTICIPANTS

154 seniors (19 men, 135 women; age range 62 to 95 years), who were residents of intermediate care and self-care retirement facilities.

INTERVENTION

Participants were randomised to one of three experimental groups: (1) a general group-based exercise (GE) programme composed of resistance training and balance training exercises; (2) a flexibility exercise and relaxation technique (FR) programme; or (3) no-exercise control (NEC). The intervention groups (GE and FR) participated in 1-hour exercise classes twice a week for a total period of 6 months.

MAIN OUTCOME MEASURES

Using standard neuropsychological tests, we assessed cognitive performance at baseline and at 6-month re-test in three domains: (1) fluid intelligence; (2) visual, verbal and working memory; and (3) executive functioning. We also assessed mood using the Geriatric Depression Scale (GDS) and the Positive and Negative Affect Schedule (PANAS).

RESULTS

The GE programme significantly improved cognitive performance of fluid intelligence compared with FR or NEC. There were also significant improvements in the positive PANAS scale within both the GE and FR groups and an indication that the two exercise programmes reduced depression in those with initially high GDS scores.

CONCLUSIONS

Our GE programme significantly improved cognitive performance of fluid intelligence in seniors residing in retirement villages compared with our FR programme and the NEC group. Furthermore, both group-based exercise programmes were beneficial for certain aspects of mood within the 6-month intervention period.

Older fallers with poor working memory overestimate their postural limits

OBJECTIVE

To compare the accuracy of perceived postural limits between older fallers with good working memory and those with poor working memory.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PARTICIPANTS

Thirty-three community-dwelling older adults with a history of falls.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We measured the accuracy of perceived postural limits by using the perceived reach test in 33 fallers. The difference between the verbal digits forward test score and the verbal digits backward test score was used to provide an index of the central executive component of working memory. Participants were then allocated into 2 groups: (1) good working memory or (2) poor working memory. Comparisons of group characteristics and scores were undertaken by using Student independent-sample t tests for differences in means between those with good working memory and those with poor memory. One hierarchical linear regression model was constructed to determine the independent association of the central executive component of working memory with the accuracy of older fallers' perceived reach capacity.

RESULTS

There was a significant difference in the mean percentage error in perceived reach between older fallers with good working memory and those with poor working memory (P=.01). The verbal digit span difference score was independently associated with the percentage error in perceived reach. The verbal digit span difference score resulted in an R(2) change of 18.2% and significantly improved the regression model (F(1,26) change, 7.45; P=.01).

CONCLUSIONS

Our novel results suggest that impaired executive functioning may increase falls risk by impairing older adults' judgment in motor planning for daily activities. However, future studies with larger sample sizes are needed to confirm our current results.

Physical activity as a mediator of the impact of chronic conditions on quality of life in older adults

BACKGROUND

Chronic conditions could negatively affect the quality of life of older adults. This may be partially due to a relative lack of physical activity. We examined whether physical activity mediates the relationship between different chronic conditions and several health outcomes that are important to the quality of life of older adults.

METHODS

The data were taken from the Canadian Community Health Survey (cycle 1.1), a cross-section survey completed in 2001. Only respondents who were 65 years or older were included in our study (N = 22,432). The Health Utilities Index Mark 3 (HUI3) was used to measure overall quality of life, and to measure selected health outcomes (dexterity, mobility, pain, cognition, and emotional wellbeing) that are considered to be of importance to the quality of life of older adults. Leisure-time physical activity was assessed by determining weekly energy expenditure (Kcal per week) based on the metabolic equivalents of self-reported leisure activities. Linear and logistic regression models were used to determine the mediating effect of leisure-time physical activity while controlling for demographic variables (age and sex), substance use (tobacco use and alcohol consumption), and obesity.

RESULTS

Having a chronic condition was associated with a relative decrease in health utility scores and a relative increase in mobility limitations, dexterity problems, pain, emotional problems (i.e., decreased happiness), and cognitive limitations. These negative consequences could be partially attributed to a relative lack of physical activity in older adults with a chronic condition (14% mediation for the HUI3 score). The corresponding degree of mediation was 18% for mobility limitations, 5% for pain, and 13% for emotional wellbeing (statistically significant mediation was not observed for the other health attributes). These values varied with respect to the different chronic conditions examined in our study.

CONCLUSION

Older adults with chronic conditions are less likely to engage in leisure-time physical activities of at least 1,000 Kcal per week, and this association partially accounts for some negative consequences of chronic conditions, including mobility limitations, pain, and emotional problems. These findings provide support for health promotion programs that facilitate or encourage increased leisure-time physical activity in older people with chronic conditions.

HipWatch: Osteoporosis Investigation and Treatment After a Hip Fracture: A 6-Month Randomized Controlled Trial

OBJECTIVE

We aimed to determine whether a novel Patient Empowerment and Physician Alerting (PEPA) intervention would improve the proportion of seniors who were investigated and treated for osteoporosis after hip fracture.

METHODS

We undertook a 6-month randomized controlled trial (RCT) in 48 women and men >/= 60 years old who had suffered a hip fracture and were admitted to a tertiary-care university hospital. The primary outcome measure was the proportion of participants offered one or more osteoporosis-specific 'best practices' measured using the Diagnosis and Management Questionnaire (DMQ). Participant responses were validated in part by physician report.

RESULTS

In the PEPA intervention group, 19 (68%) were offered one or more components of best practice care compared with 7 (35%) in the 'usual care' group (p <.05). In the PEPA group, 15 (54%) (p <.01) were prescribed bisphosphonate therapy, 8 (29%) (p <.01) had a bone mineral density scan, 11 (39%) were prescribed calcium and vitamin D (p =.32), and 9 (32%) (p <.01) were prescribed exercise. In the usual care group, 0 (0%) were prescribed bisphosphonate therapy, a bone mineral density assessment, or exercise and 6 (30%) were prescribed calcium and vitamin D.

CONCLUSIONS

This simple, inexpensive PEPA intervention resulted in far superior clinical management than did usual care in a population at high risk of future hip fracture.

School-Based Physical Activity Does Not Compromise Children's Academic Performance

PURPOSE

The purpose of this study was twofold: 1) to evaluate the effectiveness of a school-based physical activity intervention, Action Schools! BC (AS! BC), for maintaining academic performance in a multiethnic group of elementary children, and 2) to determine whether boys and girls' academic performance changed similarly after participation in AS! BC.

METHODS

This was a 16-month cluster randomized controlled trial. Ten schools were randomized to intervention (INT) or usual practice (UP). One INT school administered the wrong final test, and one UP school graded their own test, so both were excluded. Thus, eight schools (six INT, two UP) were included in the final analysis. Children (143 boys, 144 girls) in grades 4 and 5 were recruited for the study. We used the Canadian Achievement Test (CAT-3) to evaluate academic performance (TotScore). Weekly teacher activity logs determined amounts of physical activity delivered by teachers to students. Physical activity was determined with the Physical Activity Questionnaire for Children (PAQ-C). Independent t-tests compared descriptive variables between groups and between boys and girls. We used a mixed linear model to evaluate differences in TotScore at follow-up between groups and between girls and boys.

RESULTS

Physical activity delivered by teachers to children in INT schools was increased by 47 min x wk(-1) (139 +/- 62 vs 92 +/- 45, P < 0.001). Participants attending UP schools had significantly higher baseline TotScores than those attending INT schools. Despite this, there was no significant difference in TotScore between groups at follow-up and between boys and girls at baseline and follow-up.

CONCLUSION

The AS! BC model is an attractive and feasible intervention to increase physical activity for students while maintaining levels of academic performance.

Executive function is independently associated with performances of balance and mobility in community-dwelling older adults after mild stroke: implications for falls prevention

BACKGROUND

Stroke survivors have a high incidence of falls. Impaired executive-controlled processes are frequent in stroke survivors and are associated with falls in this population. Better understanding of the independent association between executive-controlled processes and physiological fall risk (i.e. performances of balance and mobility) could enhance future interventions that aim to prevent falls and to promote an independent lifestyle among stroke survivors.

METHODS

Cross-sectional analysis of 63 adults who suffered a mild stroke >1 year prior to the study, aged > or =50 years.

RESULTS

Cognitive flexibility was independently associated with performances of balance and mobility in community-dwelling older adults after mild stroke, after accounting for age, quadriceps strength of the paretic side and current physical activity level.

CONCLUSIONS

Clinicians may need to consider cognitive function when assessing and treating impaired balance and mobility in community-dwelling older adults after mild stroke.

Femoral neck cortical geometry measured with magnetic resonance imaging is associated with proximal femur strength

INTRODUCTION

Magnetic resonance imaging (MRI) is a promising medical imaging technique that we used to assess femoral neck cortical geometry.

OBJECTIVES

Our primary objective was to assess whether cortical bone in the femoral neck assessed by MRI was associated with failure load in a simulated sideways fall, with and without adjustment for total bone size. Our secondary objective was to assess the reliability of the MRI measurements.

MATERIALS AND METHODS

We imaged 34 human cadaveric proximal femora using MRI and dual-energy X-ray absorptiometry (DXA). MRI measurements of cross-sectional geometry at the femoral neck were the cortical cross-sectional area (CoCSA(MRI)), second area moment of inertia (x axis; Ix(MRI)), and section modulus (x axis; Zx(MRI)). DXA images were analyzed with the standard Hologic protocol. From DXA, we report the areal bone mineral density (aBMD(DXA)) in the femoral neck and trochanteric subregions of interest. The femora were loaded to failure at 100 mm/s in a sideways fall configuration (15 degrees internal rotation, 10 degrees adduction).

RESULTS AND OBSERVATIONS

Failure load (N) was the primary outcome. We observed that the femoral neck CoCSA(MRI) and Ix(MRI) were strongly associated with failure load (r (2)=0.46 and 0.48, respectively). These associations were similar to those between femoral neck aBMD and failure load (r (2)=0.40), but lower than the associations between trochanteric aBMD and failure load (r (2)=0.70).

CONCLUSION

We report that MRI holds considerable promise for measuring cortical bone geometry in the femoral neck and for predicting strength at the proximal femur.

Falls-related self-efficacy is independently associated with balance and mobility in older women with low bone mass

BACKGROUND

It is currently unknown whether falling is independently associated with measures of balance and mobility in older adults after accounting for relevant physiological functions. This cross-sectional study assessed the independent association of falls-related self-efficacy to balance and mobility after accounting for age, current physical activity, and performances in relevant physiological domains in 98 older women, aged 75-86 years, with low bone mass.

METHODS

Falls-related self-efficacy was assessed by the Activities-Specific Balance Confidence Scale (ABC Scale). Measures of balance and mobility included the 13-item Community Balance and Mobility Scale (CB & M Scale) and gait speed under two conditions: normal-paced and fast-paced. Physiological assessment included postural sway, foot reaction time, dominant quadriceps and dorsiflexor strength, proprioception, tactile sensitivity, edge contrast sensitivity, and visual acuity.

RESULTS

Falls-related self-efficacy was independently associated with both balance and mobility after accounting for age, current physical activity level, and performances in relevant physiological domains. Based on the standardized beta coefficients, the ABC Scale score was more associated with measures of balance and mobility than measures of physiological function.

CONCLUSION

These results highlight the independent association of falls-related self-efficacy with physical performance in older women with low bone mass. Thus, clinicians may need to consider falls-related self-efficacy when assessing and treating balance and mobility in this population, and falls-related self-efficacy may be useful as a screening tool to identify those persons with impaired balance and mobility.

Change in lean body mass is a major determinant of change in areal bone mineral density of the proximal femur: a 12-year observational study

Our objective was to assess the contribution of lean body mass (LBM) and fat body mass (FBM) to areal bone mineral density (aBMD) in women during the years surrounding menopause. We used a 12-year observational design. Participants included 75 Caucasian women who were premenopausal, 53 of whom were available for follow-up. There were two measurement periods: baseline and 12-year follow-up. At both measurement periods, bone mineral content and aBMD of the proximal femur, posterior-anterior lumbar spine, and total body was assessed using dual-energy X-ray absorptiometry (DXA). LBM and FBM were derived from the total-body scans. General health, including current menopausal status, hormone replace therapy use, medication use, and physical activity, was assessed by questionnaires. At the end of the study, 44% of the women were postmenopausal. After controlling for baseline aBMD, current menopausal status, and current hormone replacement therapy, we found that change in LBM was independently associated with change in aBMD of the proximal femur (P = 0.001). The cross-sectional analyses also indicated that LBM was a significant determinant of aBMD of all three DXA-scanned sites at both baseline and follow-up. These novel longitudinal data highlight the important contribution of LBM to the maintenance of proximal femur bone mass at a key time in women's life span, the years surrounding menopause.

Balance confidence improves with resistance or agility training. Increase is not correlated with objective changes in fall risk and physical abilities

BACKGROUND

While the fear of falling is a common psychological consequence of falling, older adults who have not fallen also frequently report this fear. Fear of falling can lead to activity restriction that is self-imposed rather than due to actual physical impairments. Evidence suggests that exercise can significantly improve balance confidence, as measured by falls-related self-efficacy scales. However, there are no prospective reports that correlate change in balance confidence with changes in fall risk and physical abilities as induced by participating in a group-based exercise program.

OBJECTIVE

The primary purpose of this prospective study was to examine the relationship between the change in balance confidence and the changes in fall risk and physical abilities in older women with confirmed low bone mass after 13 weeks of exercise participation. The secondary purpose of this study was to examine the relationship between the change in balance confidence and the change in physical activity level.

METHODS

The sample comprised 98 women aged 75-85 years with low bone mass. Participants were randomly assigned to one of three groups: resistance training (n = 32), agility training (n = 34), and stretching (sham) exercises (n = 32). The 50-min exercise classes for each study arm were held twice weekly at a local YMCA community centre.

RESULTS

Both resistance training and agility training significantly improved balance confidence by 6% from baseline after 13 weeks. However, the change in balance confidence was only weakly correlated with improved general physical function and not significantly correlated with the changes in fall risk score, postural stability, gait speed, or physical activity level. As well, we observed balance confidence enhancement in the presence of increased fall risk or deterioration in physical abilities.

CONCLUSIONS

Two different types of exercise training improved balance confidence in older women with low bone mass. This change in balance confidence was significantly correlated with change in general physical function. Because of the observation of discordance between balance confidence change and changes in fall risk and physical abilities, those who design group-based exercise programs for community-dwelling older adults may wish to consider including an education component on factors that influence fear of falling. Objective changes in fall risk factors cannot be assumed to mirror change in fear of falling and physical abilities in older adults in the short-term.

Optimizing results from pQCT: reliability of operator-dependent pQCT variables in cadavers and humans with low bone mass

Peripheral quantitative computed tomography (pQCT) can assess bone geometric properties and separate cortical from trabecular bone. Despite pQCT's potential benefits for research, most reliability and accuracy studies have used a constant acquisition and analysis protocol. There are, however, numerous steps in the pQCT scan acquisition and analysis that are operator dependent. Whether or not these influence the quality of the pQCT scans and, potentially, the precision and validity of the data collected has been little explored. We investigated how pQCT outputs changed when operator-dependent parameters were varied, particularly when the bone of interest was of low mineral density. We found that bone parameters and scan failure rate varied significantly depending on the acquisition resolution; only one scan slice at the 10 and 30% radius is required to maintain adequate precision, and reference lines for sites should use a reproducible landmark. These results provide a foundation for recommending scan acquisition and analysis options for patients with low bone mass.

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.

Older women with osteoporosis have increased postural sway and weaker quadriceps strength than counterparts with normal bone mass: overlooked determinants of fracture risk?

BACKGROUND

Fracture risk is determined by both bone health and fall risk. Evidence suggests that older women with osteoporosis may have a greater risk of falling compared with their age-matched counterparts without osteoporosis ( 1). To determine whether fall risk screening should be a routine part of medical assessment in older women with osteoporosis, a comparison of fall risk between those with osteoporosis and healthy age-matched counterparts is needed. The purpose of this study was to compare 3 established fall risk factors between these 2 groups of women.

METHODS

42 women between the ages of 64 and 75 years old participated in this study. 21 women with osteoporosis were matched by age and current physical activity level to 21 women without osteoporosis. The performance on 3 fall risk factors (quadriceps strength, balance, and functional mobility) was compared between the 2 groups using multivariate analysis of variance. The level of significance was set at p <or=.05.

RESULTS

There was an overall difference between the 2 groups on the fall risk factors (Wilk's lambda = 0.769, p =.018). Dominant quadriceps strength and composite balance score were, respectively, 18% significantly less and 11% worse in women with osteoporosis than those without. Functional mobility was not significantly different between the 2 groups.

CONCLUSIONS

This study highlights older women with osteoporosis as a high fracture risk group due to having both lower bone density, and possibly, higher fall risk compared with their age-matched counterparts without osteoporosis. Both fall risk screening and fall risk reduction may be prudent to prevent fractures in women with osteoporosis.

The effects of proprioceptive or strength training on the neuromuscular function of the ACL reconstructed knee: a randomized clinical trial

OBJECTIVES

The purpose of this study was to determine the effects of a proprioceptive training program (PT) vs. a strength training (ST) program on neuromuscular function after anterior cruciate ligament (ACL) reconstruction. The second purpose was to establish the determinants of functional ability for the operated limb.

METHODS

Ten participants with unilateral ACL reconstructions were randomly assigned to one of the following 12-week training protocols: (1) isotonic ST, and (2) PT. The outcome measures were: (1) peak torque time of the hamstring muscles (PeakTT), (2) average concentric and eccentric torques of the quadriceps and hamstring muscles, (3) one-legged single hop for distance (SLHD), (4) one-legged time hop (TH), and (5) subjective scores.

RESULTS

: There was a significant group by time interaction effect for PeakTT (P = 0.017). The PT group demonstrated greater percent change in isokinetic torques than the ST group at the end of the 12 weeks (P < or = 0.05). Participants in both groups demonstrated similar significant gains in functional ability and subjective scores (P < or = 0.014). Quadriceps strength is a determinant of functional ability for the operated limb (R2 = 0.72).

CONCLUSIONS

: Both training protocols influenced PeakTT. The beneficial effects of ST on PeakTT appear to be load-dependent, while sufficient practice may be crucial in maintaining PeakTT improvements induced by PT. Proprioceptive training alone can induce isokinetic strength gains. Restoring and increasing quadriceps strength is essential to maximize functional ability of the operated knee joint.

The influence of back pain on balance and functional mobility in 65- to 75-year-old women with osteoporosis

To determine whether the presence of back pain and its related disabilities are determinants of balance and functional mobility in a group of women with osteoporosis, we carried out a cross-sectional analysis of 93 community-dwelling women with osteoporosis between the ages of 65 and 75 years old. We assessed health history, anthropometrics, self-report of current physical activity level and self-report of back pain (intensity and pain-related disabilities). Balance was measured by computerized dynamic posturography and functional mobility was assessed by timed figure-of-eight test. The prevalence of back pain was high (75%) in this cohort of older women with osteoporosis. Age was the major determinant of both balance and functional mobility and accounted for 9% and 14% of the variance, respectively. After accounting for age, back pain explained an additional 9% of the variance in balance and 13% of the variance in functional mobility. The high prevalence of back pain demonstrates the importance of pain management in the treatment of osteoporosis. Furthermore, the finding of self-reported back pain as a determinant of both balance and functional mobility suggests that this measure may deserve attention when screening women with osteoporosis for fracture risk. Prospective studies are needed to determine whether pain management will improve balance and functional mobility.