Progressive resistance strength training for improving physical function in older adults (2009)

These highlights are produced with permission from the Cochrane Collaboration. To read the full findings and any updates, please visit: http://www.thecochranelibrary.com     

Systematic review of progressive resistance strength training in older adults

BACKGROUND: The aim of this systematic review was to quantify the effectiveness of progressive resistance strength training (PRT) to reduce physical disability in older people. METHODS: Randomized controlled trials were identified from searches of relevant databases and study reference lists and contacts with researchers. Two reviewers independently screened the trials for eligibility, rated their quality, and extracted data. Only randomized controlled trials utilizing PRT as the primary intervention in participants, whose group mean age was 60 years or older, were included. Data were pooled using fixed or random effect models to produce weighted mean differences (WMD) and 95% confidence intervals (CI). Standardized mean differences (SMD) were calculated when different units of measurement were used for the outcome of interest. RESULTS: 62 trials (n = 3674) compared PRT with a control group. 14 trials had data available to allow pooling of disability outcomes. Most trials were of poor quality. PRT showed a strong positive effect on strength, although there was significant heterogeneity (41 trials [n = 1955], SMD 0.68; 95% confidence interval [CI] 0.52, 0.84). A modest effect was found on some measures of functional limitations such as gait speed (14 trials [n = 798], WMD 0.07 meters per second; 95% CI 0.04, 0.09). No evidence of an effect was found for physical disability (10 trials [n = 722], SMD 0.01; 95% CI -0.14, 0.16). Adverse events were poorly investigated, but occurred in most studies where they were defined and prospectively monitored. CONCLUSIONS: PRT results in improvements to muscle strength and some aspects of functional limitation, such as gait speed, in older adults. However, based on current data, the effect of PRT on physical disability remains unclear. Further, due to the poor reporting of adverse events in trials, it is difficult to evaluate the risks associated with PRT.     

Cortical inhibition is reduced following short-term training in young and older adults

The purpose of this study was to investigate age-related differences in short-term training adaptations in cortical excitability and inhibition. Thirty young (21.9 ± 3.1 years) and 30 older (72.9 ± 4.6 years) individuals participated in the study. Each participant was randomly assigned to a control (n = 30) or a resistance training (n = 30) group, with equal numbers of young and older subjects in each group. Participants completed 2 days of testing, separated by 2 weeks during which time the training group participated in resistance training of the ankle dorsiflexor muscles three times per week. During each testing session, transcranial magnetic stimulation was used to generate motor evoked potentials (MEPs) and silent periods in the tibialis anterior. Hoffmann reflexes (H-reflexes) and compound muscle action potentials (M-waves) were also evoked via electrical stimulation of the peroneal nerve. At baseline, young subjects had higher maximum voluntary contraction (MVC) force (p = 0.002), larger M-wave amplitude (p < 0.001), and longer duration silent periods (p = 0.01) than older individuals, with no differences in the maximal amplitude of the MEP (p = 0.23) or H-reflex (p = 0.57). In the trained group, MVC increased in both young (17.4 %) and older (19.8 %) participants (p < 0.001), and the duration of the silent period decreased by ~15 and 12 ms, respectively (p < 0.001). Training did not significantly impact MEP (p = 0.69) or H-reflex amplitudes (p = 0.38). There were no significant changes in any measures in the control group (p ≥ 0.19) across the two testing sessions. These results indicate that a reduction in cortical inhibition may be an important neural adaptation in response to training in both young and older adults.     

Strength versus muscle power-specific resistance training in community-dwelling older adults

BACKGROUND: Loss of muscle power due to normal aging has greater functional impact than loss of strength alone. The present study compared two resistance training programs, one aimed at enhancing muscle power and one at increasing muscle strength, on muscle function and functional performance in older adults. METHODS: Sixty-seven healthy, independent older adults (65-84 years) were randomized to a high-velocity varied resistance (HV), constant resistance (ST), or nontraining control (CO) group. Participants trained twice weekly for 24 weeks using six exercises. Dynamic and isometric muscle strength, muscle power, movement velocity, muscle endurance, and a battery of functional performance tasks were assessed. Secondary outcomes included body composition, quality of life, and balance confidence. RESULTS: Muscle strength increased significantly (p <.001) and similarly in the training groups compared to controls (HV, 51.0 +/- 9.0%; ST, 48.3 +/- 6.8%; CO, 1.2 +/- 5.1%). Peak muscle power also increased with training (p <.05), with no difference between training groups. The change in peak power was 50.5 +/- 4.1%, 33.8 +/- 3.8%, and -2.5 +/- 3.9% in the HV, ST, and CO groups, respectively. Training also improved selected functional performance tasks in the HV and ST groups compared to controls (p <.05), and the HV group reported improved quality of life (p =.018). CONCLUSION: Muscle power and muscle strength improved similarly using either resistance training protocol, and these changes were accompanied by improvements in several functional performance tasks. However, improvements in the HV group occurred with less total work performed per training session.     

抗阻运动对老年心脏康复作用的研究进展

心血管疾病已成为我国居民致残致死的首要病因,心脏康复对心血管疾病患者十分重要,可以提高生活质量、运动能力和体力活动能力,降低再住院率和病死率。抗阻运动是心脏康复的重要组成部分,可以提高肌肉力量、耐力和身体活动能力。本综述旨在总结抗阻运动对老年人群心脏康复的作用,为更好的改善老年心血管病患者的预后提供帮助。     

Homocysteine and lipoprotein levels following resistance training in older adults

This investigation examined the effect of 6 months of high- or low-intensity resistance exercise on serum homocysteine and lipoprotein (a) levels in adults aged 60–80 years. Forty-three men and women completed the study protocol. Subjects were randomly assigned to a control (n=10), low-intensity (LEX, n=18), or high-intensity (HEX, n=15) group. Subjects performed 6 months of resistance training at either 50% of their one-repetition maximum for 13 repetitions (LEX) or 80% of one-repetition maximum for eight repetitions (HEX) 3 times per week for 24 weeks. The load was increased by 5% when their rating of perceived exertion dropped below 18. One-repetition maximum; serum homocysteine; lipoprotein (a); total and high-density lipoprotein cholesterol; and dietary intake of vitamins B12, B6, and folic acid were measured pre- and poststudy. Upper and lower body strength significantly (p<0.05) increased for the LEX and HEX groups. Serum homocysteine decreased 5.30% and 5.34% for the LEX and HEX groups, respectively (p<0.05), but increased 6.1% for the control group. A significant increase in lipoprotein (a) levels was noted in the control and LEX groups from pre- to poststudy. No significant differences were noted either pre- or poststudy for total and high-density lipoprotein cholesterol or any dietary variables. These data indicate that significant reductions in serum levels of homocysteine in the elderly can be derived from resistance exercise training.     

The relation between psychometric test performance and physical performance in older adults.

BACKGROUND: The relationship between cognitive function and physical disability in nondemented older adults is not well characterized. The purpose of this study was to determine the relationship between performance on psychometric measures and a modified Physical Performance Test (modified PPT) in older men and women. METHODS: One hundred twenty-five men and women aged 75 years and older, who were enrolled in randomized, controlled trials of exercise or hormone replacement therapy, were recruited from the community-at-large and from congregate living sites. Measures obtained included Trailmaking A and B tests, Cancellation Random Figure tests, Weschler Associate Learning and 20-minute Delayed Recall, Verbal Fluency test, a modified PPT, and self-reports about performance of activities of daily living, medication use, and hospitalization in the previous year. RESULTS: Simple regression analysis demonstrated that speed of performance on the Trailmaking B and Cancellation Random Figure tests was significantly associated with total modified PPT score (r = .29, p < .001 and r = .36,p < .001, respectively). A factor analysis of the psychometric test battery demonstrated that two factors, a cognitive speed factor and a memory factor, accounted for 55% of the variance in cognitive test performance. Hierarchical multiple regression analyses demonstrated that age, number of medications, and the cognitive speed factor were independent predictors of total modified PPT score. CONCLUSIONS: Cognitive processing speed is a significant component of physical frailty in this population, although it accounts for a small percentage of variance on a standardized physical performance test.     

Changes in physical performance among high-functioning older adults: a 6-year follow-up study

Purposes of the study were (1) to investigate changes in physical performance during 6 years follow-up among high-functioning older adults and (2) to describe the selection of study sample with reference to measured performance. Subjects (n=1,133) born during 1917–1941 participated in the battery of health-related fitness (HRF) tests (6.1-m walk, stair climbing, backwards walk, trunk side-bending, dynamic back extension, 1-km walk and body mass index) in 1996. Six hundred and six subjects were retested in 2002. In general, poorer fitness in the baseline assessment predicted non-participation in retesting as well as test exclusions and interruptions in retesting. The 6-year changes in the HRF showed a linear trend (P<0.01) according to age group: performance of older groups deteriorated on average more than the performance of younger groups. In most of the tests, gender was statistically significantly (P<0.05) associated with the changes in performance. The mean performance of the women deteriorated in all tests during the follow-up, while the mean performance of the men deteriorated only in the trunk side-bending, 6.1-m walk and 1-km walk tests. It can be concluded that among the subjects who participated in the follow-up testing, older age and being a woman increased deterioration in several components of HRF. Considering the selection of the subjects, the deteriorations identified are very likely underestimations of real fitness changes among this sample.     

The influence of intense Tai Chi training on physical performance and hemodynamic outcomes in transitionally frail, older adults

BACKGROUND: Few data exist to evaluate whether Tai Chi (TC) training improves physical performance and hemodynamic outcomes more than a wellness education (WE) program does among older fallers transitioning to frailty. METHODS: This 48-week randomized clinical trial was provided at 10 matched pairs of congregate living facilities in the Atlanta metropolitan area to 291 women and 20 men, who were transitionally frail, >or=70 years old, and had fallen at least once within the past year. Pairs of facilities were randomized to either TC exercise (n = 158) or WE (control) interventions (n = 153) over 48 weeks. Physical performance (freely chosen gait speed, reach, chair-rises, 360 degrees turn, picking up an object from the floor, and single limb support) and hemodynamic outcomes (heart rate and blood pressure) were obtained at baseline and after 4, 8, and 12 months. RESULTS: Mean percent change (baseline to 1 year) for gait speed increased similarly in both cohorts (TC: 9.1% and WE: 8.2%; p =.78). However, time to complete three chair-rises decreased 12.3% for TC and increased 13.7% for WE (p =.006). Baseline to 1 year mean percent change decreased among TC and increased within WE cohorts for: body mass index (-2.3% vs 1.8%; p <.0001), systolic blood pressure (-3.4% vs 1.7%; p =.02), and resting heart rate (-5.9% vs 4.6%; p <.0001). CONCLUSIONS: TC significantly improved chair-rise and cardiovascular performance. Because TC training reduced fall occurrences in this cohort, factors influencing functional and cardiovascular improvements may also favorably impact fall events.     

Effect of strength and power training on physical function in community-dwelling older adults

BACKGROUND: The performance of daily tasks, such as stair climbing or lifting an object, requires both muscle strength and power. Age-associated reductions in strength and power can affect an older adult's ability to complete daily tasks such as stair climbing and lifting a child. METHODS: The purposes of this study were to determine whether power training was more efficacious than strength training for improving whole-body physical function in older adults and to examine the relationship between changes in anaerobic power and muscle strength and changes in physical function. Thirty-nine men and women (mean age +/- SD = 72.5 +/- 6.3 years) with below-average leg extensor power were randomly assigned to control (C, n = 15), strength-training (ST, n = 13) or power-training (PT, n = 11) groups. The ST and PT groups met 3 days per week for 16 weeks; the C group maintained usual activity and attended three lectures during the course of the study. Primary outcome measures included the Continuous Scale Physical Functional Performance test, maximal strength, and anaerobic power. RESULTS: After baseline was controlled for, the Continuous Scale Physical Functional Performance test total score was significantly greater for the PT group than for the ST (p =.033) and C (p =.016) groups. Maximal strength was significantly greater for the ST group than for the C group (p =.015) after the intervention. There was no significant difference between groups for peak anaerobic power. CONCLUSIONS: Power training was more effective than strength training for improving physical function in community-dwelling older adults.     

Meaningful change and responsiveness in common physical performance measures in older adults

OBJECTIVES: To estimate the magnitude of small meaningful and substantial individual change in physical performance measures and evaluate their responsiveness. DESIGN: Secondary data analyses using distribution- and anchor-based methods to determine meaningful change. SETTING: Secondary analysis of data from an observational study and clinical trials of community-dwelling older people and subacute stroke survivors. PARTICIPANTS: Older adults with mobility disabilities in a strength training trial (n=100), subacute stroke survivors in an intervention trial (n=100), and a prospective cohort of community-dwelling older people (n=492). MEASUREMENTS: Gait speed, Short Physical Performance Battery (SPPB), 6-minute-walk distance (6MWD), and self-reported mobility. RESULTS: Most small meaningful change estimates ranged from 0.04 to 0.06 m/s for gait speed, 0.27 to 0.55 points for SPPB, and 19 to 22 m for 6MWD. Most substantial change estimates ranged from 0.08 to 0.14 m/s for gait speed, 0.99 to 1.34 points for SPPB, and 47 to 49 m for 6MWD. Based on responsiveness indices, per-group sample sizes for clinical trials ranged from 13 to 42 for substantial change and 71 to 161 for small meaningful change. CONCLUSION: Best initial estimates of small meaningful change are near 0.05 m/s for gait speed, 0.5 points for SPPB, and 20 m for 6MWD and of substantial change are near 0.10 m/s for gait speed, 1.0 point for SPPB, and 50 m for 6MWD. For clinical use, substantial change in these measures and small change in gait speed and 6MWD, but not SPPB, are detectable. For research use, these measures yield feasible sample sizes for detecting meaningful change.     

Exercise: effects on physical functional performance in independent older adults.

BACKGROUND: Age-related loss in physiologic capacities contributes to the decline in physical function in the elderly population. Despite the beneficial effects of exercise interventions on maximal physiologic capacity measures, the functional benefits have not been shown in independently living older adults. The objective of this study was to evaluate exercise in independent older adults for significant and meaningful improvements in physical function, not detected by commonly used measures of physical function. METHODS: In a randomized controlled study, 49 independently living men and women were assigned to either a nonexercise control group (Control; n = 26) or an exercise training group (Exercise; n = 23). Participants (age = 76+/-4) in good general health were recruited from retirement communities or apartments. The combined endurance and strength training was performed at 75% to 80% intensity; the groups met 3 times/week for 6 months of supervised sessions. Outcome measures included physical capacity, health status, and physical function using a newly developed performance test--the Continuous Scale-Physical Functional Performance test (CS-PFP). RESULTS: Compared to the Control group, the Exercise group showed significant increases in maximal oxygen consumption (11%) and muscle strength (33%). No significant differences were found between groups for changes in the Sickness Impact Profile, SF-36 scales, or the 6-minute walk. However, the CS-PFP score improved significantly in the Exercise group (14%, effect size 0.80). CONCLUSIONS: Independent older adults gain meaningful functional benefits from several months of exercise training. The public health importance of physical activity may relate not just to its role in preventing decline, but also to its role in enhancing physical function.     

Floor-rise strategy training in older adults

OBJECTIVES: To determine the effect of a 2-week (six-session) training intervention to improve the ability of disabled older adults to rise from the floor. DESIGN: Prospective intervention trial. SETTING: Congregate housing in Michigan. PARTICIPANTS: Subjects aged 65 and older who admitted to requiring assistance (such as from a person, equipment, or device) in performing at least one of the following mobility-related activities of daily living: transferring, walking, bathing, and toileting. INTERVENTION: Participants were randomly allocated to individual training (n = 17, mean age 81) in strategies to rise from the floor (using for example, certain key intermediate body positions) or a control chair-based flexibility intervention (n = 18, mean age 80). MEASUREMENTS: At baseline and postintervention, residents were queried regarding their rise difficulty (difficulty scale) and symptoms (symptoms scale) associated with the rise and were tested in their ability to perform timed floor-rise tasks. These tasks varied in starting position (supine vs all fours) and in use of a support to assist in rising (no support, use of an end table, use of a chair). RESULTS: Using baseline performance as the covariate, by analysis of covariance (ANCOVA), the training group showed a significant (P <.05) improvement in mean number of rise tasks completed (baseline mean 6.6, postintervention mean 7.3) versus essentially no improvement in the controls. Similarly, by ANCOVA, the training group (compared with controls) showed a significant (P <.05) improvement on the difficulty and symptoms scales. There was no intervention effect for rise time. CONCLUSIONS: A short-term, strategy-based intervention improved floor-rise ability and perceived difficulty and symptoms associated with the rise. This approach, focusing on key intermediate body positions, may be useful in training floor-rise skills, particularly in older adults at risk for falls.     

Discourse performance in older adults

Thirty-three elderly women, whose mean age was 76.2 years, and eighteen middle-aged women, whose mean age was 45.6 years, were assessed on a number of linguistic discourse tasks. The women were well educated, and most of them were or had been engaged in the teaching profession. Each woman was given narrative discourse tasks involving recall of stories, summarizing stories, giving the morals of the stories, procedural discourse tasks, interview to assess cognitive functioning and communicative abilities, and the following cognitive tests: Block Design, Symbol-Digit, Raven Coloured Progressive Matrices, and Word Fluency. The findings were that the older group generally performed more poorly than did the middle-aged group on most of the discourse tasks and cognitive tests. Within the older group, measures of quality of discourse were generally negatively related to age and positively related to scores on cognitive tests.