Changes in function and disability after resistance training: does velocity matter?: a pilot study

High-velocity power training has similar effects to traditional resistance training for functional performance in older adults: a systematic review

QUESTIONS

What is the effect of high-velocity power training (HVPT) compared with traditional resistance training (TRT) on functional performance in older adults? What is the quality of intervention reporting for the relevant literature?

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

PARTICIPANTS

Older adults (aged > 60 years), regardless of health status, baseline functional capacity or residential status.

INTERVENTIONS

High-velocity power training with the intent to perform the concentric phase as quickly as possible compared with traditional moderate-velocity resistance training performed with a concentric phase of ≥ 2 seconds.

OUTCOME MEASURES

Short Physical Performance Battery (SPPB), Timed Up and Go test (TUG), five times sit-to-stand test (5-STS), 30-second sit-to-stand test (30-STS), gait speed tests, static or dynamic balance tests, stair climb tests and walking tests for distance. The quality of intervention reporting was assessed with the Consensus on Exercise Reporting Template (CERT) score.

RESULTS

Nineteen trials with 1,055 participants were included in the meta-analysis. Compared with TRT, HVPT had a weak-to-moderate effect on change from baseline scores for the SPPB (SMD 0.27, 95% CI 0.02 to 0.53; low-quality evidence) and TUG (SMD 0.35, 95% CI 0.06 to 0.63; low-quality evidence). The effect of HVPT relative to TRT for other outcomes remained very uncertain. The average CERT score across all trials was 53%, with two trials rated high quality and four rated moderate quality.

CONCLUSION

HVPT had similar effects to TRT for functional performance in older adults, but there is considerable uncertainty in most estimates. HVPT had better effects on the SPPB and TUG, but it is unclear whether the benefit is large enough to be clinically worthwhile.

Can an Eight-Session Multicomponent Physical Exercise Program Reduce Fall Risk and Fear of Falling among the Elderly?

In older populations, falls are responsible for decrease autonomy and increased pain and injuries. With aging, fall risk is multifactorial and associated with sarcopenia, impaired balance, falls themselves and psychological factors such as fear of falling. The objectives of the present study were: (a) to test the effects of a short multicomponent physical exercise program on fall risk and fear of falling; and (b) to analyze the relationship between fall risk and fear of falling. The participants were thirty-five older persons who were engaged in an eight-session physical exercise program. Balance (i.e., One-leg Balance Test, and Functional Reach Test), lower-limb endurance (i.e., Wall-sit Test) and fear of falling were measured before and after the multicomponent physical exercise program. Results indicated an increase in balance and a diminution of fear of falling after the end of the physical exercise program (p < 0.05). The program has an effect on lower limb endurance (p > 0.05). Gains in balance were correlated to the diminution of fear of falling (p < 0.05). An 8-week multicomponent physical exercise program based on balance is efficient to reduce fall risk and fear of falling among the elderly.

Efficacy of power training to improve physical function in individuals diagnosed with frailty and chronic disease: A meta-analysis

Muscle power training with emphasis on high-velocity of concentric movement improves physical functionality in healthy older adults, and, maybe superior to traditional exercise programs. Power training may also be advantageous for patients with acute and chronic illnesses, as well as frail individuals. To determine the efficacy of power training compared with traditional resistance training on physical function outcomes in individuals diagnosed with frailty, acute illness or chronic disease. PubMed (MEDLINE), CINAHL, PEDro, Web of Science, and Google Scholar. (1) at least one study group receives muscle power training of randomized controlled trial (RCT) (2) study participants diagnosed as prefrail, frail or have an ongoing acute or chronic disease, condition or illness; (3) study participants over the age of 18; (4) publication in English language; (5) included physical function as the primary or secondary outcome measures. Two independent reviewers assessed articles for inclusion and graded the methodological quality using Cochrane Risk-of-Bias tool for RCTs. Fourteen RCTs met the inclusion criteria. In seven studies, muscle power training was more effective at improving physical function compared to control activities with a mean fixed effect size (ES) of 0.41 (p = 0.006; 95% CI 0.12 to 0.71). Power training and conventional resistance training had similar effectiveness in eight studies with a mean fixed ES of 0.10 (p = 0.061; 95% CI -0.01 to 0.40). Muscle power training is just as efficacious for improving physical function in individuals diagnosed with frailty and chronic disease when compared to traditional resistance training. The advantages of power training with reduced work per session may support power training as a preferential exercise modality for clinical populations. The findings should be interpreted with caution since generalizability is questioned due to the heterogeneity of patient populations enrolled and participants were relatively mobile at baseline.

Effectiveness of individualized training based on force-velocity profiling on physical function in older men

The study aimed to investigate the effectiveness of an individualized power training program based on force–velocity (FV) profiling on physical function, muscle morphology, and neuromuscular adaptations in older men. Forty‐nine healthy men (68 ± 5 years) completed a 10‐week training period to enhance muscular power. They were randomized to either a generic power training group (GPT) or an individualized power training group (IPT). Unlike generic training, individualized training was based on low‐ or high‐resistance exercises, from an initial force–velocity profile. Lower‐limb FV profile was measured in a pneumatic leg‐press, and physical function was assessed as timed up‐and‐go time (TUG), sit‐to‐stand power, grip strength, and stair‐climbing time (loaded [20kg] and unloaded). Vastus lateralis morphology was measured with ultrasonography. Rate of force development (RFD) and rate of myoelectric activity (RMA) were measured during an isometric knee extension. The GPT group improved loaded stair‐climbing time (6.3 ± 3.8 vs. 2.3% ± 7.3%, p = 0.04) more than IPT. Both groups improved stair‐climbing time, sit to stand, and leg press power, grip strength, muscle thickness, pennation angle, fascicle length, and RMA from baseline (p < 0.05). Only GPT increased loaded stair‐climbing time and RFD (p < 0.05). An individualized power training program based on FV profiling did not improve physical function to a greater degree than generic power training. A generic power training approach combining both heavy and low loads might be advantageous through eliciting both force‐ and velocity‐related neuromuscular adaptions with a concomitant increase in muscular power and physical function in older men.

Promoting exercise in older people to support healthy ageing

As people in the UK continue to live longer, the concept of healthy ageing has become increasingly important. Regular exercise that is appropriate for the ability of each individual can have several benefits for older people, such as slowing the loss of muscle mass, increasing aerobic capacity, maintaining cognitive function and improving health-related quality of life. This article explores the benefits of various forms of exercise and physical activity in older people, and offers practical advice that can assist nurses in supporting a person-centred approach to this aspect of care.

High-velocity resistance training as a tool to improve functional performance and muscle power in older adults

The aging process results in several physiological impairments that, in turn, may predispose older individuals to a series of restrictions on their functional capacity. These impairments are important to understand so that suitable conditions for healthier aging can be pursued. In this review, we first summarize the effects of aging on the neuromuscular system, as well as on the relation between the main age-associated physiological impairments and functional performance with an emphasis on muscle power output. We then proceed to discuss the effects of resistance training, specifically high-velocity resistance training (HVRT), on the aforementioned neuromuscular impairments, and on functional performance in healthy and mobility-limited older adults. Collectively, available evidence suggests that HVRT seems to be a safe and effective intervention for improving muscle power, functional performance, and mobility of older individuals. It also seems that mobility-limited older adults may improve power and functional performance to a greater extent than their healthy counterparts after HVRT, which is in line with the principle of diminishing returns. Considering that only a very limited number of investigations directly compared the effects of HVRT in more than one of the aforementioned groups, studies comparing the adaptations to HVRT of middle-aged adults and older adults with distinct functional capacities would be valuable to determine whether there are differences in neuromuscular adaptations, functional performance, and functional reserve among these groups.

Effectiveness of a community-delivered pneumatic machine resistance training programme (Gym Tonic) for older adults at neighbourhood senior centres - a randomized controlled trial

Background

Resistance training with pneumatic machines attenuates the age-associated loss in muscle strength and function in older adults. However, effectiveness of scaled-up pneumatic machine resistance training in the community is not known. We evaluated the effectiveness of a multi-site community-delivered 12-week pneumatic machine resistance programme (Gym Tonic (GT)) on muscle strength and physical function in older adults.

Methods

Three hundred eighteen community-dwelling older adults aged ≥65 years were randomized into 12-week (twice/week) coach-supervised-community-based-GT-programme(n = 168) and wait-list control groups(n = 150). After 12 weeks, the intervention group continued with GT-training and the control group received supervised-GT-programme for further 12 weeks (partial-crossover-design). Fried frailty score, lower-extremity muscle strength and physical function (i.e., fast and habitual gait-speed, balance, repeated-chair-sit-to-stand, short physical performance battery (SPPB)) were determined at baseline, 12 and 24 weeks. Analysis adopted a modified-intention-to-treat-approach.

Results

After 12 weeks, lower-extremity muscle strength improved by 11–26%(all p < 0.05) and fast gait-speed improved by 7%(p = 0.008) in GT-intervention group(n = 132) than controls(n = 118), regardless of frailty status. Other physical function performance did not differ between control and intervention groups after 12 weeks (all p > 0.05). Frailty score improved by 0.5 in the intervention but not control group(p = 0.004). Within the intervention group, lower-extremity muscle strength and physical function outcomes improved at 24 weeks compared with baseline (all p < 0.001). Within controls, lower-extremity muscle strength, SPPB, repeated-chair-sit-to-stand and fast gait-speed improved post-GT (24-week) compared to both pre-GT (12-week) and baseline. Programme adherence was high in intervention [0–12-weeks,90%(SD,13%); 12–24-weeks,89%(SD,17%)] and control [12–24-weeks,90%(SD,19%)] groups.

Conclusion

Community-delivered GT resistance training programme with pneumatic machines has high adherence, improves muscle strength and fast gait-speed, and can be effectively implemented at scale for older adults. Future studies could examine if including other multi-modal function-specific training to complement GT can achieve better physical/functional performance in power, balance and endurance tasks.

Trial registration

ClinicalTrials.gov, NCT04661618, Registered 10 December 2020 - Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11556-021-00273-x.

Health, social care and technological interventions to improve functional ability of older adults living at home: An evidence and gap map

Background

By 2030, the global population of people older than 60 years is expected to be higher than the number of children under 10 years, resulting in major health and social care system implications worldwide. Without a supportive environment, whether social or built, diminished functional ability may arise in older people. Functional ability comprises an individual's intrinsic capacity and people's interaction with their environment enabling them to be and do what they value.

Objectives

This evidence and gap map aims to identify primary studies and systematic reviews of health and social support services as well as assistive devices designed to support functional ability among older adults living at home or in other places of residence.

Search Methods

We systematically searched from inception to August 2018 in: MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, CENTRAL, CINAHL, PsycINFO, AgeLine, Campbell Library, ASSIA, Social Science Citation Index and Social Policy & Practice. We conducted a focused search for grey literature and protocols of studies (e.g., ProQuest Theses and Dissertation Global, conference abstract databases, Help Age, PROSPERO, Cochrane and Campbell libraries and ClinicalTrials.gov).

Selection Criteria

Screening and data extraction were performed independently in duplicate according to our intervention and outcome framework. We included completed and on-going systematic reviews and randomized controlled trials of effectiveness on health and social support services provided at home, assistive products and technology for personal indoor and outdoor mobility and transportation as well as design, construction and building products and technology of buildings for private use such as wheelchairs, and ramps.

Data Collection and Analysis

We coded interventions and outcomes, and the number of studies that assessed health inequities across equity factors. We mapped outcomes based on the International Classification of Function, Disability and Health (ICF) adapted categories: intrinsic capacities (body function and structures) and functional abilities (activities). We assessed methodological quality of systematic reviews using the AMSTAR II checklist.

Main Results

After de-duplication, 10,783 records were screened. The map includes 548 studies (120 systematic reviews and 428 randomized controlled trials). Interventions and outcomes were classified using domains from the International Classification of Function, Disability and Health (ICF) framework. Most systematic reviews (n = 71, 59%) were rated low or critically low for methodological quality.The most common interventions were home-based rehabilitation for older adults (n = 276) and home-based health services for disease prevention (n = 233), mostly delivered by visiting healthcare professionals (n = 474). There was a relative paucity of studies on personal mobility, building adaptations, family support, personal support and befriending or friendly visits. The most measured intrinsic capacity domains were mental function (n = 269) and neuromusculoskeletal function (n = 164). The most measured outcomes for functional ability were basic needs (n = 277) and mobility (n = 160). There were few studies which evaluated outcome domains of social participation, financial security, ability to maintain relationships and communication.There was a lack of studies in low- and middle-income countries (LMICs) and a gap in the assessment of health equity issues.

Authors' Conclusions

There is substantial evidence for interventions to promote functional ability in older adults at home including mostly home-based rehabilitation for older adults and home-based health services for disease prevention. Remotely delivered home-based services are of greater importance to policy-makers and practitioners in the context of the COVID-19 pandemic. This map of studies published prior to the pandemic provides an initial resource to identify relevant home-based services which may be of interest for policy-makers and practitioners, such as home-based rehabilitation and social support, although these interventions would likely require further adaptation for online delivery during the COVID-19 pandemic. There is a need to strengthen assessment of social support and mobility interventions and outcomes related to making decisions, building relationships, financial security, and communication in future studies. More studies are needed to assess LMIC contexts and health equity issues.

Longitudinal comparison of low- and high-velocity resistance training in relation to body composition and functional fitness of older adults

BACKGROUND

Functional mobility disability affects more than one in five adults over 70 years and increases to 80% by 90 years. While negative changes in mobility are multifactorial, deleterious body composition changes contribute significantly. Resistance training alters the negative trajectory of physical function as well as increases lean mass among older adults. Recently, high-velocity (HV) resistance training has been indicated as an effective intervention to increase lean mass and functional performance.

AIMS

The present investigation compared body composition, physical function, and muscular strength changes between HV and LV resistance training programs.

METHODS

Participants > 65 years (n = 53) were randomly assigned to LV, HV, or active control (AC) group and participated in their respective intervention for 48 weeks.

RESULTS

Analysis of covariance revealed no significant body composition changes over time between groups (p > 0.05). Eight-foot up-and-go performance improved in the HV and AC groups (p < 0.05) with no change in the LV group (p > 0.05) over time. Muscular strength increased in both the LV and HV groups within the first 24 weeks, while only in the LV group, muscular strength continued to increase from 24 to 48 weeks (p < 0.05).

DISCUSSION

Resistance training appears to be an effective intervention for improving aspects of physical function and muscular strength; however, no significant changes in body composition were observed over the 48-week intervention.

CONCLUSION

Findings from the current investigation support use of resistance training for improving physical function among community-dwelling older adults.

Effects of High- and Low-Velocity Resistance Training on Gait Kinematics and Kinetics in Individuals with Hip Osteoarthritis: A Randomized Controlled Trial

OBJECTIVE

The aim of this study was to investigate the effects of high-velocity (HV) and low-velocity (LV) resistance training on gait kinematics and kinetics in patients with hip osteoarthritis.

DESIGN

This was a single-blind, randomized controlled trial. Forty-six women with hip osteoarthritis were randomly allocated to the HV (n = 23) or LV (n = 23) training group. The participants underwent an 8-week home-based the HV or LV resistance-training program, involving the hip and knee muscles. Outcome measures included gait kinematics and kinetics using 3-dimensional analyses, muscle strength and power, the Harris Hip Score, and hip pain using the visual analog scale.

RESULTS

There was no significant difference in changes for any of the outcome measures between groups. After the training session, muscle power, walking speed, and cadence significantly increased only in the HV group, whereas stride length and the peak hip extension angle during gait significantly increased, and pain on the visual analog scale and the peak ankle dorsiflexion moment during gait significantly decreased only in the LV group. Muscle strength and Harris Hip Score significantly increased in both groups.

CONCLUSIONS

The results of this study may indicate that the potential effect of resistance training on abnormal gait pattern depends on movement velocities during training.

Exercise and Functional Tasks Among Adults Who Are Functionally Limited

This study compared the efficacy of 16 weeks of either resistance training, aerobic walking, or combined resistance training and aerobic walking on the performance of functional tasks among adults age 65 years and older with limited functional ability. One hundred thirty-one older adult individuals were randomized into four groups: resistance training, aerobic walking, combined resistance and aerobic walking groups, or a nonexercise control group. Each of the exercise groups documented 70% compliance with their respective exercise intervention, which included three weekly exercise sessions. At baseline, and 8 and 16 weeks following baseline, all participants completed six assessments of their functional ability. Analysis of covariance indicated that all three exercise intervention groups significantly improved measures of functional ability, with the resistance group demonstrating the most consistent gains over the six measures. These findings indicate that older adults who are functionally limited can improve their functional ability through a variety of types of exercise.

Exercise attenuates the major hallmarks of aging

Regular exercise has multi-system anti-aging effects. Here we summarize how exercise impacts the major hallmarks of aging. We propose that, besides searching for novel pharmaceutical targets of the aging process, more research efforts should be devoted to gaining insights into the molecular mediators of the benefits of exercise and to implement effective exercise interventions for elderly people.

Developing a measure of muscular power during a functional task for older adults

Background

Muscular power is an important aspect of many activities of daily living and declines at a faster rate than other fitness parameters (i.e. muscular strength and endurance). Assessing muscular power among older adults is problematic as many of the popular tests are contraindicated among older adults and field tests to assess muscular power among older adults have not been validated among older adults. Therefore, the aim of the present investigation was to determine the validity and reliability of a field test to measure of muscular power during a functional movement among community-dwelling older adults (≥ 65 years).

Methods

Twenty community-dwelling older adults (71.6 ± 5.6) volunteered to have their muscular power assessed during repeated sit-to-stand (STS) tasks. Each participant performed 10 STS with 60 s rest between trials. Muscular power was assessed during this functional movement with the Tendo as well as change in center of mass (COM) over time using cinematography.

Results

Relative power measured by Tendo was 5.34 ± 1.67 W/kg and values for COM were 5.39 ± 1.73 W/kg (p = .86). Cronbach’s alpha for Tendo muscular power for repeated trials was .98.

Conclusions

Tendo is a simple field method of determining muscular power among older adults and validation is essential. Results from this investigation support Tendo as a valid and reliable method for determining muscular power during a STS task among older adults. Clinicians may use this tool to evaluate and assess progress in older adults’ power and physical functioning.

Strength and endurance training prescription in healthy and frail elderly

Aging is associated with declines in the neuromuscular and cardiovascular systems, resulting in an impaired capacity to perform daily activities. Frailty is an age-associated biological syndrome characterized by decreases in the biological functional reserve and resistance to stressors due to changes in several physiological systems, which puts older individuals at special risk of disability. To counteract the neuromuscular and cardiovascular declines associated with aging, as well as to prevent and treat the frailty syndrome, the strength and endurance training seems to be an effective strategy to improve muscle hypertrophy, strength and power output, as well as endurance performance. The first purpose of this review was discuss the neuromuscular adaptations to strength training, as well as the cardiovascular adaptations to endurance training in healthy and frail elderly subjects. In addition, the second purpose of this study was investigate the concurrent training adaptations in the elderly. Based on the results found, the combination of strength and endurance training (i.e., concurrent training) performed at moderate volume and moderate to high intensity in elderly populations is the most effective way to improve both neuromuscular and cardiorespiratory functions. Moreover, exercise interventions that include muscle power training should be prescribed to frail elderly in order to improve the overall physical status of this population and prevent disability.

Strength and endurance training prescription in healthy and frail elderly

Aging is associated with declines in the neuromuscular and cardiovascular systems, resulting in an impaired capacity to perform daily activities. Frailty is an age-associated biological syndrome characterized by decreases in the biological functional reserve and resistance to stressors due to changes in several physiological systems, which puts older individuals at special risk of disability. To counteract the neuromuscular and cardiovascular declines associated with aging, as well as to prevent and treat the frailty syndrome, the strength and endurance training seems to be an effective strategy to improve muscle hypertrophy, strength and power output, as well as endurance performance. The first purpose of this review was discuss the neuromuscular adaptations to strength training, as well as the cardiovascular adaptations to endurance training in healthy and frail elderly subjects. In addition, the second purpose of this study was investigate the concurrent training adaptations in the elderly. Based on the results found, the combination of strength and endurance training (i.e., concurrent training) performed at moderate volume and moderate to high intensity in elderly populations is the most effective way to improve both neuromuscular and cardiorespiratory functions. Moreover, exercise interventions that include muscle power training should be prescribed to frail elderly in order to improve the overall physical status of this population and prevent disability.

Optimizing the benefits of exercise on physical function in older adults

As the number of older adults continues to rise worldwide, the prevention of physical disability among seniors is an increasingly important public health priority. Physical exercise is among the best known methods of preventing disability, but accumulating evidence indicates that considerable variability exists in the responsiveness of older adults to standard training regimens. Accordingly, a need exists to develop tailored interventions to optimize the beneficial effects of exercise on the physical function of older adults at risk for becoming disabled. The present review summarizes the available literature related to the use of adjuvant or alternative strategies intended to enhance the efficacy of exercise in improving the physical function of older adults. Within this work, we also discuss potential future research directions in this area.

Optimizing muscle power after stroke: a cross-sectional study

Background

Stroke remains a leading cause of disability worldwide and results in muscle performance deficits and limitations in activity performance. Rehabilitation aims to address muscle dysfunction in an effort to improve activity and participation. While muscle strength has an impact on activity performance, muscle power has recently been acknowledged as contributing significantly to activity performance in this population. Therefore, rehabilitation efforts should include training of muscle power. However, little is known about what training parameters, or load, optimize muscle power performance in people with stroke. The purpose of this study was to investigate lower limb muscle power performance at differing loads in people with and without stroke.

Methods

A cross-sectional study design investigated muscle power performance in 58 hemiplegic and age matched control participants. Lower limb muscle power was measured using a modified leg press machine at 30, 50 and 70% of one repetition maximum (1-RM) strength.

Results

There were significant differences in peak power between involved and uninvolved limbs of stroke participants and between uninvolved and control limbs. Peak power was greatest when pushing against a load of 30% of 1RM for involved, uninvolved and control limbs. Involved limb peak power irrespective of load (Mean:220 ± SD:134 W) was significantly lower (p < 0.05) than the uninvolved limb (Mean:466 ± SD:220 W). Both the involved and uninvolved limbs generated significantly lower peak power (p < 0.05) than the control limb (Mean:708 ± SD:289 W).

Conclusions

Significant power deficits were seen in both the involved and uninvolved limbs after stroke. Maximal muscle power was produced when pushing against lighter loads. Further intervention studies are needed to determine whether training of both limbs at lighter loads (and higher velocities) are preferable to improve both power and activity performance after stroke.

Lower limb power rehabilitation (LLPR) using interactive video game for improvement of balance function in older people

Declined balance functions have adverse effects on elderly population. Lower limbs muscle power training is currently an emerging concept in rehabilitation on individuals with decreased balance and mobility. In this prospective, controlled study, we used a human-computer interactive video-game-based rehabilitation device (LLPR) for training of lower limb muscle power in the elderly. Forty (aged >65 years) individuals were recruited from the community. Twenty participants in the exercise group received 30-min training, twice a week, using the LLPR system. The LLPR system allows participants to perform fast speed sit-to-stand (STS) movements. Twenty age-matched participants in the control group performed slow speed STS movements, as well as strengthening and balance exercises, with the same frequency and duration. The results were compared after 12 sessions (6 weeks) of training. The mechanical and time parameters during STS movement were measured using the LLPR system. Modified falls efficacy scale (MFES), Tinetti Performance-Oriented Mobility Assessment (POMA), function reach test, five times sit to stand (FTSS) and Timed Up and Go (TUG) were administered to participants as clinical assessments. Results showed that in the exercise group, all the mechanical and time parameters showed significant improvement. In control group, only the maximal vertical ground reaction force (MVGRF) improved significantly. For clinical assessments (balance, mobility, and self-confidence), exercise group showed significantly better scores. The STS movements in video-game-based training mimic real life situations which may help to transfer the training effects into daily activities. The effectiveness of lower limb muscle training is worthy of further investigation.

Skeletal muscle power: a critical determinant of physical functioning in older adults

Muscle power declines earlier and more precipitously with advancing age compared with muscle strength. Peak muscle power also has emerged as an important predictor of functional limitations in older adults. Our current working hypothesis is focused on examining lower extremity muscle power as a more discriminant variable for understanding the relationships between impairments, functional limitations, and resultant disability with aging.

Validity of an exercise test based on habitual gait speed in mobility-limited older adults

OBJECTIVE

To evaluate whether a customized exercise tolerance testing (ETT) protocol based on an individual's habitual gait speed (HGS) on level ground would be a valid mode of exercise testing older adults. Although ETT provides a useful means to risk-stratify adults, age-related declines in gait speed paradoxically limit the utility of standard ETT protocols for evaluating older adults. A customized ETT protocol may be a useful alternative to these standard methods, and this study hypothesized that this alternative approach would be valid.

DESIGN

We performed a cross-sectional analysis of baseline data from a randomized controlled trial of older adults with observed mobility problems. Screening was performed using a treadmill-based ETT protocol customized for each individual's HGS. We determined the content validity by assessing the results of the ETTs, and we evaluated the construct validity of treadmill time in relation to the Physical Activity Scale for the Elderly (PASE) and the Late Life Function and Disability Instrument (LLFDI).

SETTING

Outpatient rehabilitation center.

PARTICIPANTS

Community-dwelling, mobility-limited older adults (N=141).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Cardiac instability, ETT duration, peak heart rate, peak systolic blood pressure, PASE, and LLFDI.

RESULTS

Acute cardiac instability was identified in 4 of the participants who underwent ETT. The remaining participants (n=137, 68% female; mean age, 75.3 y) were included in the subsequent analyses. Mean exercise duration was 9.39 minutes, with no significant differences in durations being observed after evaluating among tertiles by HGS status. Mean peak heart rate and mean peak systolic blood pressure were 126.6 beats/min and 175.0 mmHg, respectively. Within separate multivariate models, ETT duration in each of the 3 gait speed groups was significantly associated (P<.05) with PASE and LLFDI.

CONCLUSIONS

Mobility-limited older adults can complete this customized ETT protocol, allowing for the identification of acute cardiac instability and the achievement of optimal exercise parameters.

Effects of high-speed power training on functional capacity and muscle performance in older women

The purpose of the study was to examine the effects of 12 weeks high-speed power training on isometric contraction (handgrip strength), maximal strength (1RM), muscle power (walking velocity, counter movement jump and ball throwing) and functional tasks of the arm and leg muscles (sit-to-stand and get-up and go). Fifty-six older women were divided into an experimental group and a control group [EG, n=28, 62.5 (5.4) years; CG: n=28, 62.5 (4.3) years]. The EG was submitted to a high-speed power training that consisted of 40% of one repetition maximum (1<RM) to 75% of 1RM); 3 sets 4-12 reps, countermovement jump and medicine ball (1.5 kg) throwing. Over the 12-week training period, the EG significantly increased dynamic and isometric strength performance (57% to 61%), muscle power (range from 14% to 40%) (P<0.05) and function (P<0.05). No significant magnitudes of increase were observed in the CG. These data indicate that high-speed power training is an effective exercise approach leading to large gains in upper and lower extremity muscle performance and function capacity.

Exercise for improving balance in older people

BACKGROUND

In older adults, diminished balance is associated with reduced physical functioning and an increased risk of falling. This is an update of a Cochrane review first published in 2007.

OBJECTIVES

To examine the effects of exercise interventions on balance in older people, aged 60 and over, living in the community or in institutional care.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, CENTRAL (The Cochrane Library 2011, Issue 1), MEDLINE and EMBASE (to February 2011).

SELECTION CRITERIA

Randomised controlled studies testing the effects of exercise interventions on balance in older people. The primary outcomes of the review were clinical measures of balance.

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently assessed risk of bias and extracted data from studies. Data were pooled where appropriate.

MAIN RESULTS

This update included 94 studies (62 new) with 9,917 participants. Most participants were women living in their own home.Most trials were judged at unclear risk of selection bias, generally reflecting inadequate reporting of the randomisation methods, but at high risk of performance bias relating to lack of participant blinding, which is largely unavoidable for these trials. Most studies only reported outcome up to the end of the exercise programme.There were eight categories of exercise programmes. These are listed below together with primary measures of balance for which there was some evidence of a statistically significant effect at the end of the exercise programme. Some trials tested more than one type of exercise. Crucially, the evidence for each outcome was generally from only a few of the trials for each exercise category. 1. Gait, balance, co-ordination and functional tasks (19 studies of which 10 provided primary outcome data): Timed Up & Go test (mean difference (MD) -0.82 s; 95% CI -1.56 to -0.08 s, 114 participants, 4 studies); walking speed (standardised mean difference (SMD) 0.43; 95% CI 0.11 to 0.75, 156 participants, 4 studies), and the Berg Balance Scale (MD 3.48 points; 95% CI 2.01 to 4.95 points, 145 participants, 4 studies).2. Strengthening exercise (including resistance or power training) (21 studies of which 11 provided primary outcome data): Timed Up & Go Test (MD -4.30 s; 95% CI -7.60 to -1.00 s, 71 participants, 3 studies); standing on one leg for as long as possible with eyes closed (MD 1.64 s; 95% CI 0.97 to 2.31 s, 120 participants, 3 studies); and walking speed (SMD 0.25; 95% CI 0.05 to 0.46, 375 participants, 8 studies).3. 3D (3 dimensional) exercise (including Tai Chi, qi gong, dance, yoga) (15 studies of which seven provided primary outcome data): Timed Up & Go Test (MD -1.30 s; 95% CI -2.40 to -0.20 s, 44 participants, 1 study); standing on one leg for as long as possible with eyes open (MD 9.60 s; 95% CI 6.64 to 12.56 s, 47 participants, 1 study), and with eyes closed (MD 2.21 s; 95% CI 0.69 to 3.73 s, 48 participants, 1 study); and the Berg Balance Scale (MD 1.06 points; 95% CI 0.37 to 1.76 points, 150 participants, 2 studies).4. General physical activity (walking) (seven studies of which five provided primary outcome data). 5. General physical activity (cycling) (one study which provided data for walking speed). 6. Computerised balance training using visual feedback (two studies, neither of which provided primary outcome data). 7. Vibration platform used as intervention (three studies of which one provided primary outcome data).8. Multiple exercise types (combinations of the above) (43 studies of which 29 provided data for one or more primary outcomes): Timed Up & Go Test (MD -1.63 s; 95% CI -2.28 to -0.98 s, 635 participants, 12 studies); standing on one leg for as long as possible with eyes open (MD 5.03 s; 95% CI 1.19 to 8.87 s, 545 participants, 9 studies), and with eyes closed ((MD 1.60 s; 95% CI -0.01 to 3.20 s, 176 participants, 2 studies); walking speed (SMD 0.04; 95% CI -0.10 to 0.17, 818 participants, 15 studies); and the Berg Balance Scale ((MD 1.84 points; 95% CI 0.71 to 2.97 points, 80 participants, 2 studies).Few adverse events were reported but most studies did not monitor or report adverse events.In general, the more effective programmes ran three times a week for three months and involved dynamic exercise in standing.

AUTHORS' CONCLUSIONS

There is weak evidence that some types of exercise (gait, balance, co-ordination and functional tasks; strengthening exercise; 3D exercise and multiple exercise types) are moderately effective, immediately post intervention, in improving clinical balance outcomes in older people. Such interventions are probably safe. There is either no or insufficient evidence to draw any conclusions for general physical activity (walking or cycling) and exercise involving computerised balance programmes or vibration plates. Further high methodological quality research using core outcome measures and adequate surveillance is required.

Is power training or conventional resistance training better for function in elderly persons? A meta-analysis

OBJECTIVE

to determine the effects of power training with high movement velocity compared with conventional resistance training with low movement velocity for older community-dwelling people.

DESIGN

systematic review of randomised controlled trials.

DATA SOURCES

the Cochrane Central Register of Controlled TRIALS, PubMed (Medline), EMBASE, CINAHL, PEDro and Scholar-Google.

TRIALS

all randomised or quasi-randomised trials investigating power training with high movement velocity versus conventional resistance training with low movement velocity in elderly persons over the age of 60 years. The primary outcomes were measures of functional outcomes; secondary outcomes were balance, gait, strength, power, muscle volume and adverse effects.

RESULTS

eleven trials were identified involving 377 subjects. The pooled effect size for the follow-up values of the functional outcomes was 0.32 in favour of the power training (95% CI 0.06 to 0.57) and 0.38 (95% CI -0.51 to 1.28) for the change value. The pooled effect from three studies for self-reported function was 0.16 in favour of power training (95% CI -0.17 to 0.49).

CONCLUSION

power training is feasible for elderly persons and has a small advantage over strength training for functional outcomes. No firm conclusion can be made for safety.

Efeitos de diferentes programas de exercícios físicos na marcha de idosos saudáveis: uma revisão

INTRODUÇÃO: Com o aumento da população idosa e da perda da capacidade funcional com o envelhecimento, há um importante interesse em investigar medidas que possam propiciar um envelhecimento mais saudável. OBJETIVOS: O objetivo deste estudo foi, por meio de uma revisão bibliográfica, verificar os efeitos dos diferentes tipos de atividade física na performance funcional da marcha em idosos saudáveis. MATERIAIS E MÉTODOS: Para esta revisão a base de dados MEDLINE foi consultada, definiram-se como limites de busca os artigos publicados entre os anos de 1999 e 2008 e que abrangessem o tema atividade física e marcha em idosos saudáveis. RESULTADOS: A maioria dos estudos aponta que programas de exercício estruturados são efetivos em se contrapor aos declínios funcionais relacionados com a idade, e os efeitos benéficos do exercício na marcha dos idosos têm sido bem estabelecidos. CONCLUSÃO: Os resultados confirmam que o treinamento de força, o treinamento funcional e os exercícios de alongamento têm efeitos positivos em diferentes parâmetros da marcha.

Dose-response relationship of resistance training in older adults: a meta-analysis

PURPOSE

The purpose of this study was to determine the dose-response relationship of resistance training (RT) to improve strength and function in older adults.

METHODS

A systematic literature search was performed in relevant databases and study reference lists to identify randomized controlled trials. Randomized controlled trials comparing the effects of different doses of strength training in older people (65 yr and older) on strength and functional outcomes were eligible. Two independent reviewers decided on study inclusion, extracted data, and assessed methodological quality. Standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated for relevant outcomes and pooled using a random-effects model.

RESULTS

Twenty-nine trials with a total of 1313 subjects (mean age = 65-81 yr) are summarized in this review. Trials comparing different training intensities show strong effects of progressive resistance training (PRT) on maximal strength in a dose-dependent manner, with high-intensity (HI) PRT being more effective compared with moderate (MI)- and low-intensity (LI) PRT (SMD [HI vs LI] = 0.88, 95% CI = 0.21-1.55; SMD [HI vs MI] = 0.62, 95% CI = 0.22-1.03). PRT was also successful for improving functional outcomes, but gains were independent of training intensity. Power training (PT) was more effective for improving muscle power (SMD [PT vs PRT] = 1.66, 95% CI = 0.08-3.24) and functional outcomes than PRT. There was only little information available on training volume and frequency.

DISCUSSION

Higher training intensities are superior to lower intensities for improving maximal strength but not necessarily for functional performance of older adults. PT has shown to be a particularly effective method for enhancing muscle power and functional performance. More research is necessary to identify the effect of different training volumes and frequencies and the dose-response relationship for very old and frail populations.

Tai Chi for osteopenic women: design and rationale of a pragmatic randomized controlled trial

Background

Post-menopausal osteopenic women are at increased risk for skeletal fractures. Current osteopenia treatment guidelines include exercise, however, optimal exercise regimens for attenuating bone mineral density (BMD) loss, or for addressing other fracture-related risk factors (e.g. poor balance, decreased muscle strength) are not well-defined. Tai Chi is an increasingly popular weight bearing mind-body exercise that has been reported to positively impact BMD dynamics and improve postural control, however, current evidence is inconclusive. This study will determine the effectiveness of Tai Chi in reducing rates of bone turnover in post-menopausal osteopenic women, compared with standard care, and will preliminarily explore biomechanical processes that might inform how Tai Chi impacts BMD and associated fracture risks.

Methods/Design

A total of 86 post-menopausal women, aged 45-70y, T-score of the hip and/or spine -1.0 and -2.5, have been recruited from primary care clinics of a large healthcare system based in Boston. They have been randomized to a group-based 9-month Tai Chi program plus standard care or to standard care only. A unique aspect of this trial is its pragmatic design, which allows participants randomized to Tai Chi to choose from a pre-screened list of community-based Tai Chi programs. Interviewers masked to participants' treatment group assess outcomes at baseline and 3 and 9 months after randomization. Primary outcomes are serum markers of bone resorption (C-terminal cross linking telopeptide of type I collagen), bone formation (osteocalcin), and BMD of the lumbar spine and proximal femur (dual-energy X-ray absorptiometry). Secondary outcomes include health-related quality-of-life, exercise behavior, and psychological well-being. In addition, kinetic and kinematic characterization of gait, standing, and rising from a chair are assessed in subset of participants (n = 16) to explore the feasibility of modeling skeletal mechanical loads and postural control as mediators of fracture risk.

Discussion

Results of this study will provide preliminary evidence regarding the value of Tai Chi as an intervention for decreasing fracture risk in osteopenic women. They will also inform the feasibility, value and potential limitations related to the use of pragmatic designs for the study of Tai Chi and related mind-body exercise. If the results are positive, this will help focus future, more in-depth, research on the most promising potential mechanisms of action identified by this study.

Trial registration

This trial is registered in Clinical Trials.gov, with the ID number of NCT01039012.

Lower extremity muscle function after strength or power training in older adults

It is unclear whether strength training (ST) or power training (PT) is the more effective intervention at improving muscle strength and power and physical function in older adults. The authors compared the effects of lower extremity PT with those of ST on muscle strength and power in 45 older adults (74.8 +/- 5.7 yr) with self-reported difficulty in common daily activities. Participants were randomized to 1 of 3 treatment groups: PT, ST, or wait-list control. PT and ST trained 3 times/wk for 12 wk using knee-extension (KE) and leg-press (LP) machines at approximately 70% of 1-repetition maximum (1RM). For PT, the concentric phase of the KE and LP was completed "as fast as possible," whereas for ST the concentric phase was 2-3 s. Both PT and ST paused briefly at the midpoint of the movement and completed the eccentric phase of the movement in 2-3 s. PT and ST groups showed significant improvements in KE and LP 1RM compared with the control group. Maximum KE and LP power increased approximately twofold in PT compared with ST. At 12 wk, compared with control, maximum KE and LP power were significantly increased for the PT group but not for the ST group. In older adults with compromised function, PT leads to similar increases in strength and larger increases in power than ST.

Progressive resistance strength training for improving physical function in older adults

BACKGROUND

Muscle weakness in old age is associated with physical function decline. Progressive resistance strength training (PRT) exercises are designed to increase strength.

OBJECTIVES

To assess the effects of PRT on older people and identify adverse events.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialized Register (to March 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to May 01, 2008), EMBASE (1980 to February 06 2007), CINAHL (1982 to July 01 2007) and two other electronic databases. We also searched reference lists of articles, reviewed conference abstracts and contacted authors.

SELECTION CRITERIA

Randomised controlled trials reporting physical outcomes of PRT for older people were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data. Data were pooled where appropriate.

MAIN RESULTS

One hundred and twenty one trials with 6700 participants were included. In most trials, PRT was performed two to three times per week and at a high intensity. PRT resulted in a small but significant improvement in physical ability (33 trials, 2172 participants; SMD 0.14, 95% CI 0.05 to 0.22). Functional limitation measures also showed improvements: e.g. there was a modest improvement in gait speed (24 trials, 1179 participants, MD 0.08 m/s, 95% CI 0.04 to 0.12); and a moderate to large effect for getting out of a chair (11 trials, 384 participants, SMD -0.94, 95% CI -1.49 to -0.38). PRT had a large positive effect on muscle strength (73 trials, 3059 participants, SMD 0.84, 95% CI 0.67 to 1.00). Participants with osteoarthritis reported a reduction in pain following PRT(6 trials, 503 participants, SMD -0.30, 95% CI -0.48 to -0.13). There was no evidence from 10 other trials (587 participants) that PRT had an effect on bodily pain. Adverse events were poorly recorded but adverse events related to musculoskeletal complaints, such as joint pain and muscle soreness, were reported in many of the studies that prospectively defined and monitored these events. Serious adverse events were rare, and no serious events were reported to be directly related to the exercise programme.

AUTHORS' CONCLUSIONS

This review provides evidence that PRT is an effective intervention for improving physical functioning in older people, including improving strength and the performance of some simple and complex activities. However, some caution is needed with transferring these exercises for use with clinical populations because adverse events are not adequately reported.

Effects of resistance training on lower-extremity impairments in older people with hip fracture

OBJECTIVE

To study the effects of resistance training on muscle strength parameters, mobility, and balance.

DESIGN

Randomized controlled trial.

SETTING

Research laboratory and senior gym.

PARTICIPANTS

Population-based sample of eligible 60- to 85-year-old community-dwelling men and women 0.5 to 7.0 years after hip fracture. Forty-six people had no contraindications and were willing to participate in the exercise trial.

INTERVENTION

Twelve-week intensive progressive strength-power training (n=24), aiming to reduce asymmetric deficit in leg muscle strength and power, or no intervention (n=22).

MAIN OUTCOME MEASURES

Isometric knee extension torque (KET) and leg extension power (LEP) measured in the weaker and stronger leg and the asymmetric deficit ([weak/sum both legs]x100%), 10-m walking speed, dynamic balance test, and self-reported outdoor mobility.

RESULTS

KET increased in both legs (P<.021), LEP tended to increase in the weaker leg (P=.071), and asymmetric LEP deficit decreased (P=.010) after training compared with the control group. LEP of the stronger leg, asymmetric KET deficit, walking speed, and balance performance were not significantly affected by training. Self-reported ability to walk outdoors improved after training. The compliance to the training was over 90%, and few adverse events (n=4; mainly musculoskeletal) were likely to be caused by the training.

CONCLUSIONS

Intensive resistance training is feasible for people with a hip fracture and improved muscle strength and power. More intensive training especially for the weaker leg may be needed to obtain more marked effects on asymmetric deficit, mobility, and balance. Also, the timing and duration of training program should be considered. (ISRCTN identifier ISRCTN34271567.)

Exercise for improving balance in older people

BACKGROUND

Diminished ability to maintain balance may be associated with an increased risk of falling. In older adults, falls commonly lead to injury, loss of independence, associated illness and early death. Although some exercise interventions with balance and muscle strengthening components have been shown to reduce falls it is not known which elements, or combination of elements, of exercise interventions are most effective for improving balance in older people.

OBJECTIVES

To present the best evidence for effectiveness of exercise interventions designed to improve balance in older people living in the community or in institutional care.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (Feb 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 1), MEDLINE (1966 to February 2006), EMBASE (1980 to February 2006), other databases and reference lists of articles. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised trials testing exercise interventions designed to improve balance in older people were included. We excluded trials of interventions targeting individuals with specific conditions in order not to broaden the scope of this review too widely. Trials were included where participants were randomised to receive the following: a single exercise intervention or a multiple exercise intervention and a control group (usual activities or attention or recreational activity). Trials comparing two or more exercise interventions and a control group were also included.

DATA COLLECTION AND ANALYSIS

Three pairs of members of the review team independently assessed trial quality and extracted data. For each trial, relative risk and 95% confidence intervals were calculated for dichotomous outcomes, and mean differences and 95% confidence intervals calculated for continuous outcomes. Where appropriate, results of comparable groups of trials were pooled and 95% confidence intervals calculated.

MAIN RESULTS

For the 34 included studies there were 2883 participants at entry. Statistically significant improvements in balance ability were observed for exercise interventions compared to usual activity. Interventions involving gait; balance; co-ordination and functional exercises; muscle strengthening; and multiple exercise types appear to have the greatest impact on indirect measures of balance. There was trend towards an improvement in balance with cycling on a static cycle. However, there was limited evidence that effects were long-lasting.

AUTHORS' CONCLUSIONS

Exercise appears to have statistically significant beneficial effects on balance ability in the short term but the strength of evidence contained within these trials is limited. Many of these mainly small studies demonstrated a range of methodological weaknesses. The failure across the included studies to apply a core set of standardised outcome measures to determine balance ability restricts the capacity to compare or pool different trials from which firm conclusions regarding efficacy can be made. Further standardisation in timing of outcome assessment is also required as is longer term follow-up of outcomes to determine any lasting effects.

Differential effects of strength versus power training on bone mineral density in postmenopausal women: a 2-year longitudinal study

OBJECTIVES

To investigate the effect of two different schemes of loading in resistance training on bone mineral density (BMD) and pain in pretrained postmenopausal women.

METHODS

53 pretrained women (mean (SD) age 58.2 (3.7) years) who carried out a mixed resistance and gymnastics programme were randomly assigned to a strength training (ST) or power training (PT) group. The difference between the two groups was the movement velocity during the resistance training (ST, 4 s (concentric)/4 s (eccentric); PT, explosive/4 s). Otherwise both groups carried out periodised progressive resistance training (10-12 exercises, 2-4 sets, 4-12 repetitions at 70-92.5% of the one-repetition maximum (2/week) for 2 years. Mechanical loading was determined with a force measuring plate during the leg press exercise. At baseline and after 2 years, BMD was measured at different sites with dual x-ray absorptiometry. Pain was assessed by questionnaire.

RESULTS

Loading magnitude, loading/unloading rate, loading amplitude and loading frequency differed significantly (p<0.001) between the two groups. After 2 years, significant between-group differences were detected for BMD (PT, -0.3%; ST, -2.4%; p<0.05) and bone area (PT, 0.4%; ST, -0.9%; p<0.05) at the lumbar spine. At the hip, there was a non-significant trend in favour of the PT group. Also the incidence of pain indicators at the lumbar spine was more favourable in the PT group.

CONCLUSION

The results show that PT may be superior for maintaining BMD in postmenopausal women. Furthermore, PT was safe as it did not lead to increased injury or pain.

Effect of augmented plantarflexion power on preferred walking speed and economy in young and older adults

With age, loss of skeletal muscle mass (sarcopenia) results in decreased muscle strength and power. Decreased strength and power, in turn, are closely linked with declines in physical function. Preferred walking speed, a marker of physical function, is slower in older adults compared to young adults. Research suggests that older adults may walk slower as a consequence of decreased plantarflexor power at push-off. In this study, we hypothesized that providing additional plantarflexion (PF) power during push-off would (1) increase preferred walking speed, and (2) reduce metabolic cost of transport (MCOT), in young and older adults. PF power was augmented using powered ankle-foot orthoses (PAFOs). The PAFOs, which use pneumatic actuators to provide an additional PF moment, were based on a design by Ferris et al. [Ferris DP, Czerniecki JM, Hannaford B. An ankle-foot orthosis powered by artificial pneumatic muscles. J Appl Biomech 2005;21:189-97.]. Nine young (23.3+/-1.6 years) and seven older (74.6+/-6.6 years) adults participated. For the young adults, eight out of nine increased their preferred walking speed when push-off power was augmented (1.18+/-0.16 to 1.25+/-0.16m/s, p=0.03). A similar, but non-significant, trend in preferred walking speed was observed for the older adults. With augmented push-off power, MCOT for young adults decreased from 0.395+/-0.057 to 0.343+/-0.047 (p=0.008); indicating that the neuromuscular system was able to adapt to use external energy to reduce metabolic cost. Only three older adults were tested but MCOT values showed a similar trend. Augmenting PF power increases gait speed and reduces MCOT in young adults. Older adults may need a longer period to take advantage of additional push-off power.

Muscle impairments and behavioral factors mediate functional limitations and disability following stroke

BACKGROUND AND PURPOSE

Stroke remains the leading cause of disability in the United States. The purposes of this study were to examine whether quantitative measures of muscle strength and power in the involved lower extremity predict functional limitations and to evaluate the contributions of behavioral factors to mediating disability and quality of life in people who have survived a stroke.

SUBJECTS AND METHODS

A cross-sectional study design was used, and measurements of muscle impairment, lower-body function, disability, quality of life, and behavioral factors were obtained for 31 community-dwelling volunteers who had experienced a single ischemic stroke in the past 6 to 24 months.

RESULTS

Stepwise regression models including impairment and behavioral measures were strong predictors of function, disability, and quality of life. Involved-extremity muscle strength and power and self-efficacy were independently associated with function, whereas depression and self-efficacy were strong predictors of disability and quality of life.

DISCUSSION AND CONCLUSION

The findings warrant future studies to determine whether interventions that address muscle strength and power, depressive symptoms, and low self-efficacy effectively improve function, reduce disability, and enhance quality of life in people who have survived a stroke.

Leg Extension Power Asymmetry and Mobility Limitation in Healthy Older Women

OBJECTIVE

To investigate the association of asymmetry in leg extension power (LEP) with walking and standing balance.

DESIGN

Cross-sectional analysis.

SETTING

Research laboratory.

PARTICIPANTS

Healthy female twins (N=419), ages 63 to 75 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The LEP difference between the stronger and the weaker leg, measured with the Nottingham power rig, was calculated. Ten-meter maximal walking velocity was assessed in a laboratory corridor on a wide (170 cm) and narrow (35 cm) track, and the ability to maintain tandem stance for 20 seconds was recorded.

RESULTS

The mean LEP difference +/- standard deviation between the legs was 15%+/-9% (P<.001). Those with large LEP difference had lower walking velocity and poorer standing balance than those with small LEP difference, in particular when the LEP of the stronger leg was below the median.

CONCLUSIONS

Even in healthy older women, substantial LEP asymmetry between the lower limbs was present, encumbering walking and standing balance. Lower-limb muscle power asymmetry warrants further study in order to develop well-targeted strategies for preventing mobility limitation in older people.

Benefits of exercise for community-dwelling older adults

This focused review highlights the benefits of exercise and physical activity for community-dwelling older adults. It is part of the study guide on geriatric rehabilitation in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on the benefits of physical activity and exercise for older adults with regard to morbidity, mortality, and disability. It discusses the appropriate preexercise screening and evaluation procedures for older adults contemplating exercise. Last, it reviews the current literature on the benefits of varying modes of exercise to modify the most prevalent chronic medical conditions of late life, including arthritis, heart disease, diabetes, stroke, pulmonary disease, and osteoporosis.

OVERALL ARTICLE OBJECTIVE

To summarize the current knowledge regarding the therapeutic benefits of exercise for community-dwelling older adults.