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OBJECTIVES: Our aim was to examine the impacts of baseline fatigue on the effectiveness of a physical activity (PA) intervention to prevent major mobility disability (MMD) and persistent major mobility disability (PMMD) in participants from the Lifestyle Interventions and Independence for Elders (LIFE) study. DESIGN: Prospective cohort of individuals aged 65 years or older undergoing structured PA intervention or health education (HE) for a mean of 2.6 years. SETTING: LIFE was a multicenter eight‐site randomized trial that compared the efficacy of a structured PA intervention with an HE program in reducing the incidence of MMD. PARTICIPANTS: Study participants (N = 1591) at baseline were 78.9 ± 5.2 years of age, with low PA and at risk for mobility impairment. MEASUREMENTS: Self‐reported fatigue was assessed using the modified trait version of the Exercise‐Induced Feelings Inventory, a six‐question scale rating energy levels in the past week. Responses ranged from 0 (none of the time) to 5 (all of the time). Total score was calculated by averaging across questions; baseline fatigue was based on the median split: 2 or higher = more fatigue (N = 856) and lower than 2 = less fatigue (N = 735). Participants performed a usual‐paced 400‐m walk every 6 months. We defined incident MMD as the inability to walk 400‐m at follow‐up visits; PMMD was defined as two consecutive walk failures. Cox proportional hazard models quantified the risk of MMD and PMMD in PA vs HE stratified by baseline fatigue adjusted for covariates. RESULTS: Among those with higher baseline fatigue, PA participants had a 29% and 40% lower risk of MMD and PMMD, respectively, over the trial compared with HE (hazard ratio [HR] for MMD =.71; 95% confidence interval [CI] =.57‐.90; P =.004) and PMMD (HR =.60; 95% CI =.44‐.82; P =.001). For those with lower baseline fatigue, no group differences in MMD (P =.36) or PMMD (P =.82) were found. Results of baseline fatigue by intervention interaction was MMD (P =.18) and PMMD (P =.05). CONCLUSION: A long‐term moderate intensity PA intervention was particularly effective at preserving mobility in older adults with higher levels of baseline fatigue. J Am Geriatr Soc 68:619–624, 2020 [ABSTRACT FROM AUTHOR]

Background: The Two-Step test is one of three official tests authorized by the Japanese Orthopedic Association to evaluate the risk of locomotive syndrome (a condition of reduced mobility caused by an impairment of the locomotive organs). It has been reported that the Two-Step test score has a good correlation with one's walking ability; however, its association with the gait pattern of older people during normal walking is still unknown. Therefore, this study aims to clarify the associations between the gait patterns of older people observed during normal walking and their Two-Step test scores.Methods: We analyzed the whole waveforms obtained from the lower-extremity joint angles and joint moments of 26 older people in various stages of locomotive syndrome using principal component analysis (PCA). The PCA was conducted using a 260 × 2424 input matrix constructed from the participants' time-normalized pelvic and right-lower-limb-joint angles along three axes (ten trials of 26 participants, 101 time points, 4 angles, 3 axes, and 2 variable types per trial).Results: The Pearson product-moment correlation coefficient between the scores of the principal component vectors (PCVs) and the scores of the Two-Step test revealed that only one PCV (PCV 2) among the 61 obtained relevant PCVs is significantly related to the score of the Two-Step test.Conclusions: We therefore concluded that the joint angles and joint moments related to PCV 2-ankle plantar-flexion, ankle plantar-flexor moments during the late stance phase, ranges of motion and moments on the hip, knee, and ankle joints in the sagittal plane during the entire stance phase-are the motions associated with the Two-Step test. [ABSTRACT FROM AUTHOR]

Background: The identification of novel rehabilitative impairments that are risk factors for mobility limitations may improve their prevention and treatment among older adults. We tested the hypothesis that impaired rhythmic interlimb ankle and shoulder coordination are risk factors for subsequent mobility limitations among older adults.Methods: We conducted a 1-year prospective cohort study of community-dwelling older adults (N = 99) aged 67 years and older who did not have mobility limitations (Short Physical Performance Battery score > 9) at baseline. Participants performed antiphase coordination of the right and left ankles or shoulders while paced by an auditory metronome. Using multivariable logistic regression, we determined odds ratios (ORs) for mobility limitations at 1-year follow-up as a function of coordination variability and asymmetry.Results: After adjusting for age, sex, body mass index, Mini-Mental State Examination score, number of chronic conditions, and baseline Short Physical Performance Battery score, ORs were significant for developing mobility limitations based on a 1 SD difference in the variability of ankle (OR = 1.88; 95% confidence interval [CI]: 1.16-3.05) and shoulder (OR = 1.96; 95% CI: 1.17-3.29) coordination. ORs were significant for asymmetry of shoulder (OR = 2.11; 95% CI: 1.25-3.57), but not ankle (OR = 0.95; 95% CI: 0.59-1.55) coordination. Similar results were found in unadjusted analyses.Conclusions: The results support our hypothesis that impaired interlimb ankle and shoulder coordination are risk factors for the development of mobility limitations. Future work is needed to further examine the peripheral and central mechanisms underlying this relationship and to test whether enhancing coordination alters mobility limitations. [ABSTRACT FROM AUTHOR]

The article discusses research conducted to investigate the contributions that gait mechanics and gait characteristics make to the energy cost of walking in older adults with impaired mobility. Researchers evaluated 50 older adults with slow and variable gait. They found that hip extension, trunk flexion and step width were factors related to the energy costs of walking. They concluded that other factors not studied in the research may also explain greater energy cost and that a closer evaluation of hip extension, step width and cadence during physical therapy gait assessments may help physical therapists to recognize factors that lead to greater energy costs in older adults.

Background and aims: This study investigated whether high-velocity high-power training (POW) improved lower extremity muscle power and quality in functionally-limited elders greater than traditional slow-velocity progressive resistance training (STR). Methods: Fifty-seven community-dwelling older adults aged 74.2±7 (range 65-94 yrs), Short Physical Performance Battery score 7.7±1.4, were randomized to either POW (n=23) (12 females), STR (n=22) (13 females) or a control group of lower extremity stretching (CON) (n=12) (6 females). Training was performed three times per week for 12 weeks and subjects completed three sets of double leg press and knee extension exercises at 70% of the one repetition maximum (1RM). Outcome measures included 1RM strength and peak power (PP). Total leg lean mass was determined using dual-energy X-ray absorptiometry. to estimate specific strength and specific PP. Results. During training, power output was consistently higher in POW compared to STR for knee extension (~2.3-fold) and leg press (~2.8-fold) exercises (p<0.01). Despite this, PP and specific PP of the knee extensors increased similarly from baseline in POW and STR compared to CON (p<0.01), and no significant time-group interaction occurred for PP of the leg extensors. However, gains in leg press specific PP were significantly greater in POW compared to both STR and CON (p<0.05). Total leg lean mass did not change within any group. Conclusions: A short-term intervention of high-velocity power training and traditional slow-velocity progressive resistance training yielded similar increases of lower extremity power in the mobility-impaired elderly. Neuromuscular adaptations to power training, rather than skeletal muscle hypertrophy, may have facilitated the improvements in muscle quality. Additional studies are warranted to test the efficacy of power training in older individuals with compromised physical functioning. [ABSTRACT FROM AUTHOR]

Background. Preventing mobility disability depends on matching interventions to individual needs. The purpose of this study is to improve targeting by determining whether mobility performance is associated with, and predicts, mobility disability hierarchically. The hypothesis is that poorer performance tested by more demanding tasks is more strongly associated with current and future mobility "limitation" (self-reported task modification or difficulty) than is that tested by less demanding tasks, in a graded manner. Methods. Data come from the Women's Health and Aging Study II (n = 436) at baseline and at 36-month follow-up. Logistic and multinomial regression models examined associations between performance on mobility tests and reported limitation in walking one-half mile, adjusting for risk factors for disability. Results. We found that 76.6% of prevalent and 88.4% of new-onset self-reported limitation fit within the hypothesized hierarchical pattern. The estimated strength of association between a decrement in lower extremity performance and reported limitation increased with task demand for the primary outcome, reported limitation in walking one-half mile. For example, the odds ratios for prevalent report of walking limitation, versus no limitation, for 10% lower performance walking, dressing, repeating chair stands, and climbing, respectively, were 1.05 (95% confidence interval, 0.97-1.17), 1.08 (1.00-1.16), 1.15 (1.06-1.25), and 1.22 (1.12-1.33). Conclusions. This study partially supports the hypothesis that mobility performance tends to follow a hierarchical pattern. For studying mild mobility disability, walking speed may not be as useful as more demanding tests. Identifying declines in performance through more demanding tests such as climbing should improve the ability to target preventive interventions to individuals at risk of mild mobility decline within a high-functioning population. [ABSTRACT FROM AUTHOR]

Background. The Short Physical Performance Battery (SPPB), which includes walking, balance, and chair stands tests, independently predicts mobility disability and activities of daily living disability. To date, however, there is no definitive evidence from randomized controlled trials that SPPB scores can be improved. Our objective was to assess the effect of a comprehensive physical activity (PA) intervention on the SPPB and other physical performance measures. Methods. A total of 424 sedentary persons at risk for disability (ages 70-89 years) were randomized to a moderate-intensity PA intervention or a successful aging (SA) health education intervention and were followed for an average of 1.2 years. Results. The mean baseline SPPB score on a scale of 0-12, with 12 corresponding to highest performance, was 7.5. At 6 and 12 months, the PA versus SA group adjusted SPPB (± standard error) scores were 8.7 ± 0.1 versus 8.0 ± 0.1, and 8.5 ± 0.1 versus 7.9 ± 0.2, respectively (p < .001). The 400-meter walking speed was also significantly improved in the PA group. The PA group had a lower incidence of major mobility disability defined as incapacity to complete a 400-meter walk (hazard ratio = 0.71, 95% confidence interval = 0.44-1.20). Conclusions. A structured PA intervention improved the SPPB score and other measures of physical performance. An intervention that improves the SPPB performance may also offer benefit on more distal health outcomes, such as mobility disability. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To compare measured lower extremity physical performance in the clinic with the methods used to carry out mobility tasks at home and to identify key factors influencing day-to-day task performance. DESIGN: Cross-sectional analysis of the Women's Health and Aging Study I. SETTING: Community-dwelling female residents of Baltimore, Maryland. PARTICIPANTS: One thousand two cognitively intact women aged 65 and older with moderate to severe physical limitations. MEASUREMENTS: Compensatory strategies reportedly used for mobility in the home, distinguishing between use of no compensatory strategies, behavioral changes only, durable medical equipment (DME) with or without behavioral change, and human help; measured lower extremity (LE) physical performance (gait speed, timed chair stands, balance). RESULTS: There was a statistically significant difference in LE physical performance between women using the four types of compensatory strategy ( P<.001). Women who used DME for mobility in the home had worse performance than those using human help who in turn had worse performance than those with behavioral changes only; women reporting no compensatory strategies for in-home mobility performed best. Sequential multivariate logistic regressions identified several factors other than LE physical performance that were associated with use of specific compensatory strategies. Medical conditions, education, and environmental barriers influenced whether compensatory strategies were used at all, whereas income, contact with health providers, and availability of help in the home influenced the type of compensatory strategy. CONCLUSION: Physical abilities are an important factor influencing use of compensatory strategies for mobility, but several other factors also influence the ways that women adapt to mobility limitations. [ABSTRACT FROM AUTHOR]

Objectives: To define clinically relevant cutpoints for usual gait speed and to investigate their predictive value for health-related events in older persons. Design: Prospective cohort study. Setting: Health, Aging and Body Composition Study. Participants: Three thousand forty-seven well-functioning older persons (mean age 74.2). Measurements: Usual gait speed on a 6-m course was assessed at baseline. Participants were randomly divided into two groups to identify (Sample A; n=2,031) and then validate (Sample B; n=1,016) usual gait-speed cutpoints. Rates of persistent lower extremity limitation events (mean follow-up 4.9 years) were calculated according to gait speed in Sample A. A cutpoint (defining high- (<1 m/s) and low risk (≥1 m/s) groups) was identified based on persistent lower extremity limitation events. The predictive value of the identified cutpoints for major health-related events (persistent severe lower extremity limitation, death, and hospitalization) was evaluated in Sample B using Cox regression analyses. Results: A graded response was seen between risk groups and health-related outcomes. Participants in the high-risk group had a higher risk of persistent lower extremity limitation (rate ratio (RR)=2.20, 95% confidence interval (CI)=1.76–2.74), persistent severe lower extremity limitation (RR=2.29, 95% CI=1.63–3.20), death (RR=1.64, 95% CI=1.14–2.37), and hospitalization (RR=1.48, 95% CI=1.02–2.13) than those in the low-risk group. Conclusion: Usual gait speed of less than 1 m/s identifies persons at high risk of health-related outcomes in well-functioning older people. Provision of a clinically meaningful cutpoint for usual gait speed may facilitate its use in clinical and research settings. [ABSTRACT FROM AUTHOR]

Aging is proposed as being reflective of a gradual reduction in the coupling of physiological output, which is predicted to reduce the irregularity in the dynamics of the individual outputs. Hypothesized is that this change in coupling with aging results in decreased irregularity across tasks but also demands a larger change in coupling in order to alter the dynamics of individual motor output. Young (18-23 years), old (60-65 years), and older (70-75 years) participants (N = 35) performed tasks that required maintaining a still posture and flexion-extension at a preferred frequency with the right index finger, with a 3-dimensional accelerometer attached above the fingernail. Irregularity of the acceleration data on the mediolateral and superoinferior axes was measured using approximate entropy (ApEn), while entropy of their continuous relative phase measured the coupling between them. Mixed model 3 (Age) x 2 (Task) ANOVAs found significant effects of age and task on the mediolateral axis but only a significant task effect on the superoinferior axis. Old and older adults had significantly lower ApEn on both tasks mediolaterally. A significant Age x Task interaction on relative phase entropy showed significant changes in entropy across tasks for the old and older adults, but not so for the young. The relation between irregularity and relative phase entropy was captured using a 3-parameter power law, with r² values of 0.4. The irregularity in the motor output of the elderly was decreased across both tasks on the mediolateral axis of motion. This suggests that changes in irregularity with aging are more apparent in actions that play a stabilizing role. The relative phase data support the hypothesis that reduced ability to adapt to different tasks is not due to a decrease in coupling strength alone. Rather, the elderly employ a greater magnitude of change in coupling strength while adapting the dynamics of the individual motor outputs to different motor tasks. [ABSTRACT FROM AUTHOR]