Biomedical subjects

Jonathan Bean

Publications and source records attributed to Jonathan Bean.

8 recordsLinked to original sources

PubMed2006

The pathway from musculoskeletal pain to mobility difficulty in older disabled women.

Little is known about the pathway from musculoskeletal pain to mobility difficulty among older persons. We examined potential physical and psychological mediators of the pain-disability relationship in the Women's Health and Aging Study (WHAS), a cohort of women aged 65 who had at least mild disability at baseline. Pain was classified according to location and severity (widespread pain; lower extremity pain; other pain; none or mild pain in only one site). Among women without a lot of difficulty in stair climbing (n=676) or walking (n=510) at baseline, those who reported widespread pain were more likely than those with none or mild pain to develop a lot of difficulty with mobility during the 3 year follow-up. The likelihood for mobility difficulty was unchanged after adjusting for physical impairments and symptoms of depression and anxiety (walking aOR=1.85, 95%CI, 1.08-3.17; stair climbing, aOR=2.68, 95%CI, 1.56-4.62). Lower extremity pain was associated with increased likelihood for difficulty with climbing stairs but not with walking. However, this association was attenuated after adjusting for physical impairments and psychological symptoms (aOR=1.66, 95%CI, 0.99-2.77). Pain was not associated with increased risk for becoming unable to walk or climb stairs. The findings suggest that pain is a unique domain as a cause of disablement, independent of the usual pathway to disability via physical impairments. Research is needed to better understand the development of pain-related disability in order to determine optimum approaches to prevent and treat mobility disability in older persons with persistent pain.

Activities of Daily Living↗

PubMed2004

Impact of muscle power and force on gait speed in disabled older men and women.

BACKGROUND: The purpose of this study was to explore the relationship between muscle power output at different external resistances and performance of functional tasks. The authors hypothesized that power at 40% skeletal muscle 1 repetition maximum (1RM), in which contraction velocity is high, would explain more of the variability in tasks such as level walking than would peak power or 1RM strength, in which contraction velocity is lower. METHODS: Participants were men and women (n = 48; ages 65-91 years) with physical disability as evidenced by 2 or more deficits on the Medical Outcomes Study Short Form physical function subscale or a score of 9 or less on the Established Populations for the Epidemiologic Studies of the Elderly short physical performance battery. Muscle strength (1RM) was measured using a bilateral leg press exercise, and power output was determined by selecting the highest power output from 6 different contraction velocities: 40%, 50%, 60%, 70%, 80%, and 90% 1RM. Functional performance tasks consisted of habitual gait velocity (HGV) and stair climb (SC) and chair rise (CR) performance. Separate linear regression models were fit for each of the 3 dependent variables (SC, CR, HGV) using 1RM strength, power at 70% 1RM, and power at 40% 1RM as independent variables. All models were adjusted for age, body mass, and sex. RESULTS: Lower extremity power at 70% and 40% 1RM demonstrated greater associations with SC and HGV than did 1RM strength, whereas power at 40% 1RM demonstrated similar or stronger associations with all functional tasks compared with 1RM strength. Power at 40% 1RM explained the same or more of the variability in SC (R(2) = .42 [regression coefficient = -.169 +/- .06] vs .43 [-.206 +/- .071]), CR (R(2) = .28 [-.154 +/- .057] vs .24 [-.152 + .070]) and HGV (R(2) = .59 [.214 + .37] vs .51 [.223 +/- .049]) compared with power at 70% 1RM. Power at 40% 1RM explained more of the variability in the lower intensity (HGV) compared with the higher intensity (SC or CR) functions. CONCLUSIONS: Power output at 40% of 1RM explained more of the variability in HGV than did power at 70% 1RM, suggesting that measures such as HGV that require a lower percentage of maximal strength to perform might be more sensitive to differences in contraction velocity. Because HGV is highly predictive of subsequent disability, future studies should evaluate the determinants of muscle power output at low external resistances.

Aged↗

PubMed2003

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

OBJECTIVE: To compare the effects of high- and low-velocity resistance training on functional performance and disability outcomes in physically limited older women. DESIGN: A total of 16 wk of high-velocity resistance training or traditional low-velocity resistance training consisting of knee extension and leg press exercises was performed three times per week by 30 women with self-reported disability to compare their effect on functional performance and disability. Tests of dynamic balance, stair-climb time, chair-rise time, and gait velocity were used to assess changes in functional performance. Changes in disability were assessed using the Medical Outcomes Study Short Form. RESULTS: Dynamic balance and stair-climb time improved 8% and 10%, respectively, with training. Self-reported disability, physical functioning, role physical, and mental health improved 11, 9, and 5% with training, respectively. There were no significant differences between high- and low-velocity training groups. CONCLUSIONS: High- and low-velocity training achieved similar improvements in functional performance and disability. Improvements in functional performance and disability were modest compared with robust increases in strength and power. Specific modes of training or behavioral strategies may be necessary to optimize improvements in these outcomes.

Aged↗

PubMed2002

High-velocity resistance training increases skeletal muscle peak power in older women.

OBJECTIVES: Peak power declines more precipitously than strength with advancing age and is a reliable measure of impairment and a strong predictor of functional performance. We tested the hypothesis that a high-velocity resistance-training program (HI) would increase muscle power more than a traditional low-velocity resistance-training program (LO). DESIGN: Randomized controlled trial. SETTING: University-based human physiology laboratory. PARTICIPANTS: Thirty women with self-reported dis-ability (aged 73 + 1, body mass index 30.1 + 1.1 kg/mn). INTERVENTION: We conducted a randomized trial comparing changes in skeletal muscle power and strength after 16 weeks of HI or LO. Training was performed three times per week, and subjects completed three sets (8-10 repetitions) of leg press (LP) and knee extension (KE) exercises at 70% of the one-repetition maximum (IRM). MEASUREMENTS: One-repetition maximum (1 RM) and peak power for KE and LP. RESULTS: LP and KE relative training force and total work were similar between groups (P > .05). However, HI generated significantly higher power during training sessions than LO for LP (3.7-fold greater, P < .001) and KE (2.1-fold greater, P < .001). Although LP and KE 1RM muscle strength increased similarly in both groups asa result of the training (P < .001), LP peak power increased significantly more in HI than in LO (267 W vs 139 W, P < .001). Furthermore, HI resulted in a significantly greater improvement in LP power at 40%, 50%, 60%,70%, 80%, and 90% of the 1 RM than did LO (P <.05). CONCLUSIONS: HI improved 1RM strength similarly and was more effective in improving peak power than was traditional LO in older women. Improvements in lower extremity peak power may exert a greater influence on age-associated reductions in physical functioning than other exercise interventions.

Aged↗

PubMed2002

Weighted stair climbing in mobility-limited older people: a pilot study.

OBJECTIVES: To evaluate weighted stair climbing exercise (SCE) as a means of increasing lower extremity muscle power in mobility-limited older people. DESIGN: Single-blinded, randomized controlled pilot study. SETTING: Human physiology laboratory of a metropolitan university. PARTICIPANTS: Forty-five community-dwelling people aged 65 and older who had baseline mobility limitations manifested by scores of 11 or lower on the Short Physical Performance Battery (SPPB). INTERVENTIONS: Subjects were randomized into one of two 12-week exercise programs. The intervention group (SCE) (n = 23) ascended and descended stairs, at a set pace, while wearing a weighted vest. The control group (WALK) (n = 22) participated in a standardized walking program. MEASUREMENTS: Primary and secondary outcomes included measures of muscle power and strength, submaximal aerobic capacity, and physical performance. RESULTS: SCE produced 17% improvement in double leg press peak power in comparison with WALK (P =.013) and significant improvement in stair climbing power from baseline (12%). Improvement in submaximal aerobic performance was equivalent for both groups. Although not statistically significant, effect size estimates suggest that SCE can potentially influence knee extension power and strength. Stair climb time was improved in both groups, whereas SCE produced significant improvements from baseline SPPB score in a subcohort of participants. CONCLUSIONS: These findings suggest that SCE maybe a useful component of a home exercise program designed to enhance lower extremity muscle power, aerobic capacity, and functional performance. Further investigation is needed involving larger sample sizes and direct comparisons with other forms of resistance training.

Aged↗

PubMed2002

Musculoskeletal pain and risk for falls in older disabled women living in the community.

OBJECTIVES: To determine whether musculoskeletal pain increased risk for falls in older women with disabilities. DESIGN: Prospective population-based cohort study. SETTING: The city and county of the eastern area of Baltimore. PARTICIPANTS: One thousand two women aged 65 and older, participants in the Women's Health and Aging Study, representing the one-third of older women who were living at home with disabilities, followed semiannually for 3 years beginning in 1991. MEASUREMENTS: Pain was categorized into four groups according to severity and location. Widespread pain was defined as pain in the upper and lower extremities and in the axial skeletal region, with moderate to severe pain in at least one region (> or = 4 on a 10-point numeric rating scale, 10 = excruciating pain). Moderate to severe lower extremity pain that did not meet criteria for widespread pain was the next category. The reference category was no pain or mild pain in one site. The additional category of "other pain" was pain that did not fit into the other three groups. The occurrence of falls and fall-related injuries were assessed at each interview. RESULTS: Of the 940 women who participated in at least one follow-up examination, 39% fell in first year; of the survivors, 36% fell in Year 2, and 39% in Year 3. After adjusting for several major risk factors for falls, women with widespread pain had an increased likelihood of falling during follow-up (adjusted odds ratio (AOR) = 1.66, 95% confidence interval (CI) = 1.25-2.21) compared with those with no or mild pain in only one musculoskeletal site. Women who had other musculoskeletal pain but not widespread pain or lower extremity pain also had an increased risk of falls (AOR = 1.36, 95% CI = 1.02-1.82). Among women with musculoskeletal pain, risk for falls was lower in those who used daily analgesic medication. Risk for recurrent falls and self-reported fractures due to falls was also elevated in women with musculoskeletal pain, most consistently in women with widespread pain. CONCLUSIONS: Musculoskeletal pain, particularly widespread pain, is a substantial risk factor for falls in older women with disabilities. These findings add an important dimension to our understanding of the multifactorial processes leading to falls in older persons.

Accidental Falls↗

PubMed2002

Noise-enhanced vibrotactile sensitivity in older adults, patients with stroke, and patients with diabetic neuropathy.

OBJECTIVE: To test the hypothesis that vibrotactile detection thresholds in older adults, patients with stroke, and patients with diabetic neuropathy can be significantly reduced with the introduction of mechanical noise. DESIGN: A randomized controlled study. SETTING: A university research laboratory. PARTICIPANTS: Twelve healthy elderly subjects (age range, 67-85y), 5 patients with stroke (age range, 24-64y), and 8 patients with diabetic neuropathy (age range, 53-77y). INTERVENTIONS: Each subject's detection thresholds (ie, minimum level of stimulus to be detected) for a vibrotactile stimulus without and with mechanical noise (ie, random vibration with a small intensity) were determined by using a 4-, 2-, and 1-stepping algorithm. The stimuli were applied to the fingertip and/or to the first metatarsal of the foot. MAIN OUTCOME MEASURE: Detection threshold for a vibrotactile stimulus. RESULTS: The detection threshold at the fingertip for the vibration stimulus with mechanical noise was significantly lower than that without mechanical noise for all 12 elderly subjects, for 4 of the 5 patients with stroke, and all 8 patients with diabetic neuropathy. For the 8 patients with diabetes, mechanical noise also significantly reduced the vibrotactile detection threshold at the foot. CONCLUSIONS: Reduced vibrotactile sensitivity in older adults, patients with stroke, and patients with diabetic neuropathy can be significantly improved with input mechanical noise. Noise-based techniques and devices may prove useful in overcoming age- and disease-related losses in sensorimotor function.

Adult↗

PubMed2002

Associating the onset of motor impairments with disability progression in nursing home residents.

OBJECTIVES: To evaluate the association between the onset of movement impairments and disability progression in nursing home residents. DESIGN: Retrospective cohort analysis of data from the State of New York Minimal Data Set, version 2.0, between November 1998 and October 1999. Participants were nursing home residents (n = 84,346) in the State of New York. Items defined as "functional limitation in range of motion" and "lack of voluntary movement" served as measures of movement impairments. Scores on the activities of daily living summary scale served as a measure of disability. Age, sex, measures of cognition, depression, and measures of medical stability served as adjustment variables. RESULTS: After adjusting for age, sex, cognition, depression, and measures of medical stability, the onset of either singular or combined movement impairments in voluntary movement or range of motion was associated with a concurrent step-wise loss in activities of daily living (P < 0.001). The progression in activities of daily living loss occurred regardless of location or limb type. CONCLUSION: This study directly links the onset of movement impairments with disability progression. These findings have important implications for physiatrists and other practitioners of geriatric rehabilitation.

Activities of Daily Living↗