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Dennis R Taaffe

Publications and source records attributed to Dennis R Taaffe.

17 recordsLinked to original sources
PubMed2006

Short-term resistance training and the older adult: the effect of varied programmes for the enhancement of muscle strength and functional performance.

Although it is well recognized that resistance training is an efficient strategy to enhance physical performance in older adults, less is known about the most effective type of resistive exercise or the role of functional training. This study compared the effectiveness of three varied short-term (8 weeks) training protocols on muscle strength and functional performance in older men and women aged 65-84 years. Participants underwent twice-weekly high-velocity varied-resistance training (HV), twice weekly slow to moderate-velocity constant-resistance training (CT), combined once weekly high-velocity varied-resistance and once weekly gymnasium-based functional training (CB) or no training (CO). Dynamic muscle strength (1RM) of six muscle groups was assessed using isotonic equipment and functional performance by a battery of tests. Following 8 weeks of training, whole-body muscle strength increased (P<0.001) by 22.0 +/- 12.5% (mean +/- SD), 21.7 +/- 11.0% and 26.1 +/-14.4% in HV, CT and CB, respectively, compared to CO (-1.8 +/- 7.2%). In between group comparisons, only the HV group displayed greater chair rise ability (P =0.010) than the CO group, while differences among groups approached significance for the fast 6-m walk and the stair climb test (P = 0.017 and 0.041 respectively). Within groups, the HV group significantly improved in stair-climbing and chair rise ability (P</=0.001) while CB improved in the fast 6-m walk (P = 0.003) and CT improved their static balance, as assessed by the functional reach test (P<0.001). This study indicates that twice weekly high-velocity resistance training is superior to strength and combined functional and resistance training for improving some power-orientated functional tasks. Although other functional performance improvements were modest among the training protocols, short-term combined once weekly resistance and once weekly functional training in older adults was as effective in enhancing muscle strength as twice-weekly resistance training. These results have important implications for older adults who are unable or unwilling to frequently attend exercise facilities.

Aged↗
PubMed2006

Resistance training and reduction of treatment side effects in prostate cancer patients.

PURPOSE: To examine the effect of progressive resistance training on muscle function, functional performance, balance, body composition, and muscle thickness in men receiving androgen deprivation for prostate cancer. METHODS: Ten men aged 59-82 yr on androgen deprivation for localized prostate cancer undertook progressive resistance training for 20 wk at 6- to 12-repetition maximum (RM) for 12 upper- and lower-body exercises in a university exercise rehabilitation clinic. Outcome measures included muscle strength and muscle endurance for the upper and lower body, functional performance (repeated chair rise, usual and fast 6-m walk, 6-m backwards walk, stair climb, and 400-m walk time), and balance by sensory organization test. Body composition was measured by dual-energy x-ray absorptiometry and muscle thickness at four anatomical sites by B-mode ultrasound. Blood samples were assessed for prostate specific antigen (PSA), testosterone, growth hormone (GH), cortisol, and hemoglobin. RESULTS: Muscle strength (chest press, 40.5%; seated row, 41.9%; leg press, 96.3%; P < 0.001) and muscle endurance (chest press, 114.9%; leg press, 167.1%; P < 0.001) increased significantly after training. Significant improvement (P < 0.05) occurred in the 6-m usual walk (14.1%), 6-m backwards walk (22.3%), chair rise (26.8%), stair climbing (10.4%), 400-m walk (7.4%), and balance (7.8%). Muscle thickness increased (P < 0.05) by 15.7% at the quadriceps site. Whole-body lean mass was preserved with no change in fat mass. There were no significant changes in PSA, testosterone, GH, cortisol, or hemoglobin. CONCLUSIONS: Progressive resistance exercise has beneficial effects on muscle strength, functional performance and balance in older men receiving androgen deprivation for prostate cancer and should be considered to preserve body composition and reduce treatment side effects.

Aged↗
PubMed2006

Sarcopenia--exercise as a treatment strategy.

BACKGROUND: Sarcopenia, the age related decline in muscle mass, is associated with a reduction in muscle function, physical performance, quality of life, and loss of independence. Exercise, specifically resistance (weight) training, has been shown to be an effective countermeasure, arresting decline and substantially improving physical function. OBJECTIVE: This article reviews the prevalence of sarcopenia, underlying processes, and the role of exercise as a treatment strategy. Practical guidelines are provided for prescribing exercise to older patients. DISCUSSION: The aging neuromuscular system is highly responsive to resistance training. Resistance can be applied using specialised weight training machines, elastic bands, objects around the home, or body weight. Training once or twice a week targeting the major muscle groups at moderate intensity is sufficient for improvement.

Aged↗
PubMed2005

Hearing sensitivity and bone mineral density in older adults: the Health, Aging and Body Composition Study.

Bone mineral density (BMD) may be associated with hearing loss in older adults. Demineralization of the cochlear capsule has been associated with hearing loss in those with Paget's disease of the bone and otosclerosis. Osteoporosis may also result in cochlear capsule demineralization. We hypothesized that lower hip BMD and lower heel ultrasound measurements would be associated with hearing loss in a population-based sample of 2,089 older black and white men and women. Bone parameters and hearing function were measured at the fourth clinical follow-up visit. Audiometric threshold testing was used to measure air- and bone-conduction hearing sensitivity. BMD of the hip and its subregions was measured using dual-energy X-ray absorptiometry. Calcaneal bone measurements [broadband ultrasound attenuation (BUA), speed of sound (SOS) and the quantitative ultrasound index (QUI)] were obtained using heel ultrasound. After adjusting for known hearing loss risk factors, no association was found between hearing and any of the bone measurements in whites and black women. In black men, however, lower hip BMD was associated with higher odds of hearing loss; for each standard deviation decrease in total hip BMD, the odds of hearing loss were 1.41 (95% confidence interval 1.08, 1.83), 1.39 (95% CI 1.07, 1.82) for femoral neck BMD and 1.65 (95% CI 1.26, 2.16) for trochanter BMD. Conductive hearing loss was associated with lower heel ultrasound measurements, though only among white men. The results of this study are mixed and inconclusive. Lower BMD of the hip and its subregions was associated with hearing loss among black men, but not among whites or black women. Lower measurements on heel ultrasound were associated with conductive hearing loss, though only among white men. These results suggest that axial and appendicular bone parameters may be modestly associated with hearing loss in older men, but not in women.

Absorptiometry, Photon↗
PubMed2005

Bone loss in Crohn's disease: exercise as a potential countermeasure.

Crohn's disease (CD) is associated with a number of secondary conditions including osteoporosis, which increases the risk of bone fracture. The cause of metabolic bone disease in this population is believed to be multifactorial and may include the disease itself and associated inflammation, high-dose corticosteroid use, weight loss and malabsorption, a lack of exercise and physical activity, and an underlying genetic predisposition to bone loss. Reduced bone mineral density has been reported in between 5% to 80% of CD sufferers, although it is generally believed that approximately 40% of patients suffer from osteopenia and 15% from osteoporosis. Recent studies suggest a small but significantly increased risk of fracture compared with healthy controls and, perhaps, sufferers of other gastrointestinal disorders such as ulcerative colitis. The role of physical activity and exercise in the prevention and treatment of CD-related bone loss has received little attention, despite the benefits of specific exercises being well documented in healthy populations. This article reviews the prevalence of and risk factors for low bone mass in CD patients and examines various treatments for osteoporosis in these patients, with a particular focus on physical activity.

Bone Density↗
PubMed2005

The effect of hormone replacement therapy and/or exercise on skeletal muscle attenuation in postmenopausal women: a yearlong intervention.

Hormone replacement therapy (HRT) has been reported to exert a positive effect on preserving muscle strength following the menopause, however, the mechanism of action remains unclear. We examined whether the mechanism involved preservation of muscle composition as determined by skeletal muscle attenuation. Eighty women aged 50-57 years were randomly assigned to either: HRT, exercise (Ex), HRT+exercise (ExHRT), and control (Co) for 1 year. The study was double-blinded with subjects receiving oestradiol and norethisterone acetate (Kliogest) or placebo. Exercise included progressive high-impact training for the lower limbs. Skeletal muscle attenuation in Hounsfield units (HU) was determined by computed tomography of the mid-thigh. Areas examined were the quadriceps compartment (includes intermuscular adipose tissue), quadriceps muscles, the posterior compartment and posterior muscles. Muscle performance was determined by knee extensor strength, vertical jump height, and running speed over 20 m. Fifty-one women completed the intervention. Vertical jump height and running speed improved in the HRT and ExHRT groups compared with Co (interaction, P<0.01). For both the quadriceps compartment and quadriceps muscles, HU significantly increased (interaction, P<or=0.005) for HRT, Ex, and ExHRT compared with Co. For the posterior compartment, HU for the HRT and ExHRT were significantly increased compared with Co, while for posterior muscles, ExHRT was significantly greater than Co. Although the effects were modest, the results indicate that HRT, either alone or combined with exercise, may play a role in preserving/improving skeletal muscle attenuation in early postmenopausal women and thereby exert a positive effect on muscle performance.

Adipose Tissue↗
PubMed2005

Resistance exercise dosage in older adults: single- versus multiset effects on physical performance and body composition.

OBJECTIVES: To determine whether variation in resistance exercise volume affects muscle function and physical performance response in older adults. DESIGN: A randomized trial with subjects assigned to a single-set (1-SET) or three-set (3-SET) exercise group. SETTING: An exercise facility at the University of Queensland. PARTICIPANTS: Twenty-eight community-dwelling men and women aged 65 to 78. INTERVENTION: Progressive resistance training consisting of seven exercises targeting the major muscle groups of the upper and lower body performed on exercise machines twice weekly for 20 weeks at eight-repetition maximum (RM) intensity. MEASUREMENTS: Muscle function included isotonic muscle strength (1-RM) of the seven exercises, isokinetic and isometric knee extensor strength, and muscle endurance for the chest press and leg press exercises. Physical performance included timed chair rise, usual and fast 6-m walk, 6-m backwards walk, 400-m walk, floor rise to standing, and stair climbing ability. In addition, body composition was determined using dual energy x-ray absorptiometry. RESULTS: Isotonic muscle strength increased in both exercise groups for all seven exercises (P<.01), with the gain in the 3-SET group greater (P<.05) for the seated row, triceps extension, and knee extension (analysis of covariance). Similarly, muscle endurance gains were greater for the 3-SET than the 1-SET group (P<.01), with no significant difference between groups for isokinetic and isometric knee extensor strength. Both groups improved (P<.05) in the chair rise (1-SET, 10.1%; 3-SET, 13.6%), 6-m backwards walk (1-SET, 14.3%; 3-SET, 14.8%), 400-m walk (1-SET, 3.8%; 3-SET, 7.4%), and stair climbing test (1-SET, 7.7%; 3-SET, 6.4%), with the only difference between groups for the 400-m walk (P<.05). There was no difference between groups for change in body composition. CONCLUSION: Resistance training consisting of only single-set exercises is sufficient to significantly enhance muscle function and physical performance, although muscle strength and endurance gains are greater with higher-volume work. These findings have application in designing time-efficient exercise regimens to enhance neuromuscular function in older adults.

Absorptiometry, Photon↗
PubMed2005

Anabolic responses to resistance training in older men and women: a brief review.

Resistance training has been shown to be the most effective exercise mode to induce anabolic adaptations in older men and women. Advances in imaging techniques and histochemistry have increased the ability to detect such changes, confirming the high level of adaptability that remains in aging skeletal muscle. This brief review presents a summary of the resistance-training studies that directly compare chronic anabolic responses to training in older (>60 years) men and women. Sixteen studies are summarized, most of which indicate similar relative anabolic responses between older men and women after resistance training. Relatively small sample sizes in most of the interventions limited their ability to detect significant sex differences and should be considered when interpreting these studies. Future research should incorporate larger sample sizes with multiple measurement time points for anabolic responses.

Adaptation, Physiological↗
PubMed2005

Estrogen replacement, muscle composition, and physical function: The Health ABC Study.

PURPOSE: Although the beneficial effects of estrogen use on cardiovascular and cognitive function in postmenopausal women have been recently discredited, controversy remains regarding its usefulness for maintaining skeletal muscle mass or strength. Therefore, the purpose of this study was to determine whether estrogen use is associated with enhanced muscle composition and, if so, whether this translates into improved strength and physical function. METHODS: Cross-sectional analysis of 840 well-functioning community-dwelling white women (current estrogen replacement therapy (ERT) users = 259, nonusers = 581) aged 70-79 yr participating in the Health, Aging and Body Composition Study. Muscle composition of the midthigh by computed tomography included cross-sectional area (CSA) of the quadriceps, hamstrings, intermuscular fat and subcutaneous fat, and muscle attenuation in Hounsfield units (HU) as a measure of muscle density. Isometric hand grip and isokinetic knee extensor strength were assessed by dynamometry. Physical function was assessed using a summary scale that included usual 6-m walk and narrow walk speed, repeated chair stands, and standing balance. RESULTS: In analyses of covariance adjusted for relevant confounders, quadriceps muscle CSA and HU were greater in current ERT than non-ERT women (P < 0.05). Grip strength was also greater (P < 0.05) in women taking ERT while knee extensor strength approached significance (P < 0.10). However, differences in muscle composition and strength were modest at < or =3.3%. There was no difference by ERT status for the hamstring muscles, fat CSA, or for physical function. CONCLUSION: The associations between ERT and muscle composition and strength were minor and did not translate into improved physical function. Initiation of ERT for preservation of muscle composition and function may not be indicated.

Aged↗
PubMed2004

Determinants of lower-body muscle power in early postmenopausal women.

OBJECTIVES: To investigate the association between muscle size, density, and fiber composition; body composition; maximal isometric knee extension strength (KES); and lower-body muscle power in healthy postmenopausal women. DESIGN: Cross-sectional analysis of baseline data from a 1-year randomized controlled experiment. SETTING: University-based research laboratory. PARTICIPANTS: Seventy-eight healthy postmenopausal women aged 50 to 57. MEASUREMENTS: Maximal lower-body muscle power was assessed using vertical jump height (VJH). Maximal isometric KES was measured on a dynamometer chair. Computed tomography scans were used to determine lean-tissue cross-sectional area and density of the thigh and lower leg muscles. Relative area occupied by type I, IIa, IIax, and IIx muscle fibers was assessed from the vastus lateralis muscle. lean body mass and total body fat mass were assessed using bioelectrical impedance. RESULTS: High VJH was associated with low body fat mass, high KES, and high density of thigh and lower leg muscles. Multivariate linear regression modeling revealed that high thigh muscle density (beta=0.242; P=.019), relative area occupied by the fastest muscle fiber types (IIax+IIx; beta=0.246; P=.007), KES (beta=0.247; P=.007), and low body fat mass (beta=-0.455; P<.001) were independently associated with high VJH, accounting for 45% of the variability in VJH. CONCLUSION: This study showed that thigh muscle composition, muscle strength, and body fat mass are important determinants of lower-body muscle power production during weight-bearing activity in healthy postmenopausal women.

Aged↗
PubMed2004

Physical activity, exercise, and inflammatory markers in older adults: findings from the Health, Aging and Body Composition Study.

OBJECTIVES: To examine the association between physical activity and inflammatory markers, with consideration for body fatness and antioxidant use. DESIGN: Cross-sectional study, using baseline data from the Health, Aging and Body Composition Study. SETTING: Metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Black and white, well-functioning men and women (N=3,075), aged 70 to 79. MEASUREMENTS: Interviewer-administered questionnaires of previous-week household, walking, exercise, and occupational/volunteer physical activities. Analysis of covariance was used to examine the association between activity level and serum C-reactive protein (CRP), interleukin-6 (IL-6), and plasma tumor necrosis factor alpha (TNFalpha) with covariate adjustment. Antioxidant supplement use (multivitamin, vitamins E or C, beta carotene) was evaluated as an effect modifier of the association. RESULTS: Higher levels of exercise were associated with lower levels of CRP (P<.01), IL-6 (P<.001), and TNFalpha (P=.02) (e.g., CRP=1.95 mg/L for no exercise and 1.72 for >180 min/wk). Adjustment for body fatness attenuated the associations somewhat. Use of antioxidant supplements modified the CRP (P(interaction)=.01) and IL-6 (P(interaction)=.08) associations such that concentrations were low in those taking supplements (e.g., CRP=1.79-1.84 across exercise levels) and higher in nonsupplement users who did no exercise (2.03) than in those who did the most (1.72). Among nonexercisers, higher levels of other physical activity were related to lower levels of CRP (P<.01) and IL-6 (P=.02) but not TNFalpha (P=.36), even after accounting for body fat. CONCLUSION: Inflammatory markers are lower in older adults with higher levels of exercise and nonexercise activity and in antioxidant supplement users regardless of exercise level.

Aged↗
PubMed2004

Single- vs. multiple-set resistance training: recent developments in the controversy.

The number of sets in a resistance training program remains a major point of discussion and controversy. Studies prior to 1998 demonstrated inconsistent findings between single-set and multiple-set programs; however, recent evidence suggests that multiple sets promote additional benefits following short- and long-term training. The rationale supporting multiple sets is that the number of sets is part of the exercise volume equation, and the volume of exercise is crucial in producing the stimulus necessary to elicit specific physiological adaptations. The purpose of this paper is to present an overview of recent resistance training studies comparing single and multiple sets. However, it should be noted that studies to date have been conducted in young and middle-aged adults, and it remains to be determined if the additional benefits accrued with multiple-set training also occurs for older adults, especially the frail elderly.

Adaptation, Physiological↗
PubMed2003

Poor correlation of mid-femoral measurements by CT and hip measurements by DXA in the elderly.

BACKGROUND AND AIMS: Hip fracture is a devastating event in terms of outcome in the elderly, and the best predictor of hip fracture risk is hip bone density, usually measured by dual X-ray absorptiometry (DXA). However, bone density can also be ascertained from computerized tomography (CT) scans, and mid-thigh scans are frequently employed to assess the muscle and fat composition of the lower limb. Therefore, we examined if it was possible to predict hip bone density using mid-femoral bone density. METHODS: Subjects were 803 ambulatory white and black women and men, aged 70-79 years, participating in the Health, Aging and Body Composition (Health ABC) Study. Bone mineral content (BMC, g) and volumetric bone mineral density (vBMD, mg/cm3) of the mid-femur were obtained by CT, whereas BMC and areal bone mineral density (aBMD, g/cm2) of the hip (femoral neck and trochanter) were derived from DXA. RESULTS: In regression analyses stratified by race and sex, the coefficient of determination was low with mid-femoral BMC, explaining 6-27% of the variance in hip BMC, with a standard error of estimate (SEE) ranging from 16 to 22% of the mean. For mid-femur vBMD, the variance explained in hip aBMD was 2-17% with a SEE ranging from 15 to 18%. Adjusting aBMD to approximate volumetric density did not improve the relationships. In addition, the utility of fracture prediction was examined. Forty-eight subjects had one or more fractures (various sites) during a mean follow-up of 4.07 years. In logistic regression analysis, there was no association between mid-femoral vBMD and fracture (all fractures), whereas a 1 SD increase in hip BMD was associated with reduced odds for fracture of approximately approximately 60%. CONCLUSIONS: These results do not support the use of CT-derived mid-femoral vBMD or BMC to predict DXA-measured hip bone mineral status, irrespective of race or sex in older adults. Further, in contrast to femoral neck and trochanter BMD, mid-femur vBMD was not able to predict fracture (all fractures).

Absorptiometry, Photon↗
PubMed2003

Lower extremity physical performance and hip bone mineral density in elderly black and white men and women: cross-sectional associations in the Health ABC Study.

BACKGROUND: Aging is characterized by declines in physical capacity and bone mineral density (BMD), both of which contribute to increased risk for fracture. However, it is unclear if these factors coexist or are independent in elderly people, and if a relationship does exist, whether it varies by sex and/or race. METHODS: Data are from 847 white women, 723 black women, 927 white men, and 544 black men aged 70-79 years participating in the Health Aging and Body Composition (ABC) Study, a cohort of well-functioning community-dwelling elders. BMD (g/cm(2)) of the hip (femoral neck and trochanter) was determined by dual X-ray absorptiometry. Physical capacity measures included knee extensor strength, repeated chair-stands, gait speed (6 m), walking endurance (400 m), and standing balance. RESULTS: In analyses of BMD as a continuous measure, BMD and physical performance were most consistently related at the trochanter in black women, even after adjusting for body size and several covariates including physical activity. For each performance measure, black women in the bottom quartile(s) had lower BMD than those in the top quartile(s). For the femoral neck, there was a significant association with performance tasks, except for the 400-m walk. In comparison, only chair-rise performance was related to BMD at the femoral neck, and knee extensor strength, chair-rise performance, and balance with the trochanter in white women. For white and black men, trends existed only for lower BMD in those with poorer knee extensor strength. CONCLUSIONS: In this cohort of well-functioning young-old seniors, physical capacity is only modestly related to BMD at the hip. The association was strongest in black women, who as a group exhibited the poorest functional capacity in the cohort. Our data show that, although both poorer physical performance and low BMD are risk factors for fracture, they remain largely independent in the well-functioning young-old, except in black women. This independence suggests that interventions to reduce fracture incidence should be targeted at improving both physical performance and bone density.

Absorptiometry, Photon↗
PubMed2002

Relationship of interleukin-6 and tumor necrosis factor-alpha with muscle mass and muscle strength in elderly men and women: the Health ABC Study.

BACKGROUND: A decline in muscle mass and muscle strength characterizes normal aging. As clinical and animal studies show a relationship between higher cytokine levels and low muscle mass, the aim of this study was to investigate whether markers of inflammation are associated with muscle mass and strength in well-functioning elderly persons. METHODS: We used baseline data (1997-1998) of the Health, Aging, and Body Composition (Health ABC) Study on 3075 black and white men and women aged 70-79 years. Midthigh muscle cross-sectional area (computed tomography), appendicular muscle mass (dual-energy x-ray absorptiometry), isokinetic knee extensor strength (KinCom), and isometric grip strength were measured. Plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS: Higher cytokine levels were generally associated with lower muscle mass and lower muscle strength. The most consistent relationship across the gender and race groups was observed for IL-6 and grip strength: per SD increase in IL-6, grip strength was 1.1 to 2.4 kg lower (p <.05) after adjustment for age, clinic site, health status, medications, physical activity, smoking, height, and body fat. An overall measure of elevated cytokine level was created by combining the levels of IL-6 and TNF-alpha. With the exception of white men, elderly persons having high levels of IL-6 (>1.80 pg/ml) as well as high levels of TNF-alpha (>3.20 pg/ml) had a smaller muscle area, less appendicular muscle mass, a lower knee extensor strength, and a lower grip strength compared to those with low levels of both cytokines. CONCLUSIONS: Higher plasma concentrations of IL-6 and TNF-alpha are associated with lower muscle mass and lower muscle strength in well-functioning older men and women. Higher cytokine levels, as often observed in healthy older persons, may contribute to the loss of muscle mass and strength that accompanies aging.

Aged↗
PubMedDate not supplied

Improved physical performance in older adults undertaking a short-term programme of high-velocity resistance training.

BACKGROUND: The age-related loss of muscle power in older adults is greater than that of muscle strength and is associated with a decline in physical performance. OBJECTIVE: To investigate the effects of a short-term high-velocity varied resistance training programme on physical performance in healthy community-dwelling adults aged 60-80 years. METHODS: Subjects undertook exercise (EX; n=15) or maintained customary activity (controls, CON; n=10) for 8 weeks. The EX group trained 2 days/week using machine weights for three sets of eight repetitions at 35, 55, and 75% of their one-repetition maximum (the maximal weight that an individual can lift once with acceptable form) for seven upper- and lower-body exercises using explosive concentric movements. RESULTS: Fourteen EX and 10 CON subjects completed the study. Dynamic muscle strength significantly increased (p=0.001) in the EX group for all exercises (from 21.4 +/- 9.6 to 82.0 +/- 59.2%, mean +/- SD) following training, as did knee extension power (p <0.01). Significant improvement occurred for the EX group in the floor rise to standing (10.4 +/- 11.5%, p=0.004), usual 6-metre walk (6.6 +/- 8.2%, p=0.010), repeated chair rise (10.4 +/- 15.6%, p=0.013), and lift and reach (25.6 +/- 12.1%, p=0.002) performance tasks but not in the CON group. CONCLUSIONS: Progressive resistance training that incorporates rapid rate-of-force development movements may be safely undertaken in healthy older adults and results in significant gains in muscle strength, muscle power, and physical performance. Such improvements could prolong functional independence and improve the quality of life.

Activities of Daily Living↗