Efficacy and feasibility of a novel tri-modal robust exercise prescription in a retirement community: a randomized, controlled trial

OBJECTIVES: To test the feasibility and efficacy of current guidelines for multimodal exercise programs in older adults. DESIGN: Randomized, controlled trial. SETTING: Retirement village. PARTICIPANTS: Thirty-eight subjects (14 men and 24 women) aged 76.6 +/- 6.1. INTERVENTION: A wait list control or 10 weeks of supervised exercise consisting of high-intensity (80% of one-repetition maximum (1RM)) progressive resistance training (PRT) 3 days per week, moderate-intensity (rating of perceived exertion 11 to 14/20) aerobic training 2 days per week, and progressive balance training 1 day per week. MEASUREMENTS: Blinded assessments of dynamic muscle strength (1RM), balance, 6-minute walk, gait velocity, chair stand, stair climb, depressive symptoms, self-efficacy, and habitual physical activity level. RESULTS: Higher baseline strength and psychological well-being were associated with better functional performance. Strength gains over 10 weeks averaged 39+/-31% in exercise, versus 21+/-24% in controls (P=.10), with greater improvements in hip flexion (P=.01), hip abduction (P=.02), and chest press (P=.04) in the exercise group. Strength adaptations were greatest in exercises in which the intended continuous progressive overload was achieved. Stair climb power (12.3+/-15%, P=.002) and chair stand time (-7.1+/-15%, P=.006) improved significantly and similarly in both groups. Reduction in depressive symptoms was significantly related to compliance (attendance rate r=-0.568, P=.009, PRT progression in loading r=-0.587, P=.02, and total volume of aerobic training r=-0.541, P=.01), as well as improvements in muscle strength (r=-0.498, P=.002). CONCLUSION: Robust physical and psychological adaptations to exercise are linked, although volumes and intensities of multiple exercise modalities sufficient to cause significant adaptation appear difficult to prescribe and adhere to simultaneously in older adults.     

Moderate-intensity resistance exercise training in patients with chronic heart failure improves strength, endurance, heart rate variability, and forearm blood flow

BACKGROUND: Resistance exercise training was applied to patients with chronic heart failure (CHF) on the basis that it may partly reverse deficiencies in skeletal muscle strength and endurance, aerobic power (VO(2peak)), heart rate variability (HRV), and forearm blood flow (FBF) that are all putative factors in the syndrome. METHODS AND RESULTS: Thirty-nine CHF patients (New York Heart Association Functional Class=2.3+/-0.5; left ventricular ejection fraction 28%+/-7%; age 65+/-11 years; 33:6 male:female) underwent 2 identical series of tests, 1 week apart, for strength and endurance of the knee and elbow extensors and flexors, VO(2peak), HRV, FBF at rest, and FBF activated by forearm exercise or limb ischemia. Patients were then randomized to 3 months of resistance training (EX, n=19), consisting of mainly isokinetic (hydraulic) ergometry, interspersed with rest intervals, or continuance with usual care (CON, n=20), after which they underwent repeat endpoint testing. Combining all 4 movement patterns, strength increased for EX by 21+/-30% (mean+/-SD, P<.01) after training, whereas endurance improved 21+/-21% (P<.01). Corresponding data for CON remained almost unchanged (strength P<.005, endurance P<.003 EX versus CON). VO(2peak) improved in EX by 11+/-15% (P<.01), whereas it decreased by 10+/-18% (P<.05) in CON (P<.001 EX versus CON). The ratio of low-frequency to high-frequency spectral power fell after resistance training in EX by 44+/-53% (P<.01), but was unchanged in CON (P<.05 EX versus CON). FBF increased at rest by 20+/-32% (P<.01), and when stimulated by submaximal exercise (24+/-32%, P<.01) or limb ischemia (26+/-45%, P<.01) in EX, but not in CON (P<.01 EX versus CON). CONCLUSIONS: Moderate-intensity resistance exercise training in CHF patients produced favorable changes to skeletal muscle strength and endurance, VO(2peak), FBF, and HRV.     

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.     

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.     

Effects of long-term resistive training on mobility and strength in older adults with diabetes

BACKGROUND: Strength training has been shown to be beneficial in older adults. However, very little data exist on the effects of strength training in older diabetics. METHODS: 31 community-dwelling older adults with diabetes (mean age = 66.1 years) were randomly assigned to either an exercise (EX) or control (CO) group. The EX group trained the plantar flexors, knee extensors, knee flexors, hip extensors, and hip flexors muscle groups at 50%, 60%, and 70% of 1-repetition maximum, 2.6 days a week, for 24 months. Mobility tests included the timed up and go, 50-foot walk, and walking up and down 8 stairs. Strength and mobility for both groups were evaluated at 6-month intervals. RESULTS: There was a group and time effect as the EX group increased 31.4% (p <.001) in strength for all muscle groups after the first 6 months of training, and the strength gains were retained for the duration of the training intervention. There was also a group and time effect for mobility as performance increased 8.6% and 9.8% (p =.032 and p = 0.031) for the first 6 and 12 months, respectively, but decreased to 4.6% above baseline at the end of the intervention. There were essentially no changes from baseline strength or mobility values for the CO group. CONCLUSION: In conclusion, these data suggest that a moderate-intensity resistive-training program can improve mobility and strength for the duration of a 24-month intervention in older adults with diabetes, thus potentially reducing the rate of mobility loss during aging.     

Effects of aerobic and resistive exercise training on glucose disposal and skeletal muscle metabolism in older men

BACKGROUND: Aging is associated with insulin resistance, primarily as a result of physical inactivity and increased abdominal obesity. We hypothesized that aerobic (AEX) or resistive (RT) exercise training would result in comparable improvements in glucose disposal in older men, but that there would be different metabolic adaptations in skeletal muscle. METHODS: Thirty-nine older (63+/-1 years, mean+/-standard error of the mean), overweight and obese (body mass index=30.3+/-0.4 kg/m2) men were assigned to AEX (treadmill walking and/or jogging, n=19) or RT (upper and lower body, n=20) programs 3 d/wk for 6 months, with 9 completing AEX and 13 completing RT. Testing before and after the exercise programs included body composition, euglycemic-hyperinsulinemic clamps, and vastus lateralis muscle biopsies. RESULTS: Maximal oxygen consumption (VO2max) increased by 16% after AEX (p<.01), while leg and arm muscle strength increased by 45+/-5% and 27+/-5% after RT (p<.0001). Although participants were monitored to maintain their body weight during the exercise program, body weight decreased by 2% after AEX (p<.05), and increased by 2% after RT (p<.05). Whole-body glucose disposal, determined during the last 30 minutes of a 2-hour 480 pmol/m2/min euglycemic-hyperinsulinemic clamp, increased comparably by 20%-25% after AEX (51+/-5 to 61+/-5 microM/kgfat-free mass/min, p<.05) and RT (49+/-3 to 58+/-3 microM/kgfat-free mass/min, p<.05). The increase in vastus lateralis muscle glycogen synthase fractional activity in response to insulin stimulation was significantly higher after AEX compared to after RT (279+/-59% compared to 100+/-28% change, p<.05). Neither AEX nor RT altered muscle glycogen synthase total activity, glycogen content, or levels of phosphotidylinositol 3-kinase. CONCLUSION: These results suggest that AEX and RT result in comparable improvements in glucose metabolism in older men, whereas an increase in insulin activation of glycogen synthase occurred only with AEX. These improvements in insulin sensitivity could reduce the risk of metabolic syndrome and type 2 diabetes and attenuate the development of cardiovascular disease.     

Exercise capacity and quadriceps muscle metabolism following training in subjects with COPD

The aim of the study was to determine whether 16 sessions of exercise training, completed twice weekly, alters exercise capacity, quadriceps muscle metabolism, cross-sectional area (CSA) and strength in subjects with chronic obstructive pulmonary disease (COPD). We studied (a) 10 COPD subjects (mean age+/-sem = 71+/-2 years; FEV1 = 0.99+/-0.1 L) before and after 16 sessions of exercise training, and (b) 10 healthy subjects (age = 68+/-3 years). The COPD subjects underwent an incremental peak exercise test using a cycle ergometer and a 6-min walk test: both improved following exercise training (P < 0.05). Magnetic resonance spectroscopy measurements, in quadriceps muscle, of post-exercise phosphocreatinine (PCr) recovery kinetics were used to assess mitochondrial function in vivo: in the COPD subjects pre-training this was 19+/-8% lower than in healthy subjects (P = 0.03), but a 38+/-12% increase was seen in the COPD subjects following training (P = 0.003). Magnetic resonance imaging was used to assess quadriceps CSA: after training in the COPD subjects this showed a 7+/-2% increase (P = 0.03). Quadriceps strength, measured by the best of five maximum voluntary contractions, also showed a 32+/-11% increase in the COPD subjects (P = 0.007). Sixteen sessions of exercise training, performed twice weekly, increased exercise capacity as well as quadriceps mitochondrial capacity, CSA and strength in the subjects with COPD.     

Age-related declines in knee extensor strength and physical performance in healthy Hispanic and Caucasian women

Hispanic women may undergo greater age-related reductions in physical functional capacity compared with Caucasian women. If so, a greater rate of decline in muscle strength with age could contribute. We tested this hypothesis in 82 healthy sedentary Caucasian (n = 37) and Hispanic (n = 45) adult women aged 21-78 years of similar socioeconomic status. Absolute one-repetition maximum (1-RM) strength of the knee extensors (KE) declined with advancing age in the Caucasian (r = -.55, p < .01) and Hispanic (r = -.45, p < .01) women; the rates of decline were similar in the two groups (-7% to 8% x decade(-1), p = .60). KE strength normalized for thigh fat-free mass (FFM) also declined with age in the Caucasian (r = .52, p < .01) and Hispanic (r = -.41, p < .01) women, the rates of decline being similar (-6% to 7% x decade(-1), p = .66). For all functional performance tasks (10-m walk, stair ascent, stair descent, and chair stand), performance time increased with advancing age (mean of four tasks vs age: Caucasian, r = .64, p < .01; Hispanic, r = .56, p < .01). Absolute and normalized KE 1-RM were inversely related to the mean time for the four performance tasks (r = -.34 to -.58, all p < .01). Normalized KE 1-RM was the best independent predictor of the age-related decline in task performance in both groups. These cross-sectional findings do not support the hypothesis that Hispanic ethnicity per se is associated with a greater decline in KE strength and performance tasks associated with KE strength in healthy women.     

Strength training normalizes resting blood pressure in 65- to 73-year-old men and women with high normal blood pressure.

OBJECTIVE: To determine the effects of heavy resistance strength training (ST) on resting blood pressure (BP) in older men and women. DESIGN: Prospective intervention study. SETTING: University of Maryland Exercise Science Laboratory. PARTICIPANTS: Twenty-one sedentary, healthy older men (69 +/- 1 year, n = 11) and women (68 +/- 1 year, n = 10) served as subjects for the study. INTERVENTION: Six months of progressive whole body ST performed 3 days per week using Keiser K-300 air-powered resistance machines. MEASUREMENTS: One-repetition maximum (1 RM) strength was measured for seven different exercises before and after the ST program. Resting BP was measured on six separate occasions before and after ST for each subject. RESULTS: Substantial increases in 1 RM strength were observed for upper body (UB) and lower body (LB) muscle groups for men (UB: 215 vs 265 kg; LB: 694 vs 838 kg; P < .001) and women (UB: 128 vs 154 kg; LB: 441 vs 563 kg; P < .001). The ST program led to reductions in both systolic (131 +/- 2 vs 126 +/- 2 mm Hg, P < .010) and diastolic (79 +/- 2 vs 75 +/- 1 mm Hg, P < .010) BP. Systolic BP was reduced significantly in men (134 +/- 3 vs 127 +/- 2 mm Hg, P < .01) but not in women (128 +/- 3 vs 125 +/- 3 mm Hg, P < .01), whereas diastolic BP was reduced following training in both men (81 +/- 3 vs 77 +/- 1, mm Hg, P = .054) and women (78 +/- 2 vs 74 +/- 2 mm Hg, P = .055). CONCLUSIONS: Six months of heavy resistance ST may reduce resting BP in older persons. According to the latest guidelines from the Joint National Committee for the Detection, Evaluation, and Treatment of Hypertension, the changes in resting BP noted in the present study represent a shift from the high normal to the normal category.     

Effects of a one-year exercise training program in adults over 70 years old: a study with a control group

BACKGROUND AND AIMS: Exercise training is known to improve exercise tolerance in elderly subjects. Therefore the present study aimed at investigating the effects of one year of combined endurance and resistance training in healthy older people. METHODS: After baseline evaluation, subjects were assigned to either the training group (n=24, age 77.2+/-3.6) or the control group (n=16, age 76.1+/-4.8). Subjects in the control group did not change anything in their everyday activities, whereas subjects in the training group underwent moderately intensive combined exercise training, 3 hours a week over the course of one year. Breath-by-breath oxygen uptake and heart rate were measured at each workload during the symptom-limited cardiopulmonary exercise test. Performance on the 6-minute (6-MWT) and 200-meter (200-MWT) walk tests was registered and maximal strength was measured on knee extensor and plantar flexor muscles. RESULTS: After training, oxygen uptake was significantly increased, both at the ventilatory threshold (+11.6%, p<0.01) and at the end of exercise (+14.8%, p<0.001). The distance walked in 6 min (+10%, p<0.001), the time required to cover 200 m (-7.3%, p<0.001) and the maximal muscle strength (+15.2% and +17.4% for knee extensors and plantar flexors respectively, p<0.05) also improved after training. All these parameters had not significantly changed in the control group after the one-year period. CONCLUSIONS: The results of the present study show that one year of combined exercise training is well-tolerated and improves aerobic capacity, performance on field tests and muscle strength in healthy subjects over 70 years old.     

Effects of exercise and weight loss on cardiac risk factors associated with syndrome X

BACKGROUND: Patients with high blood pressure (BP) often exhibit syndrome X, an aggregation of abnormalities in carbohydrate and lipoprotein metabolism associated with increased risk of coronary heart disease (CHD). The present study evaluated the effects of a 6-month intervention involving either aerobic exercise training alone (EX only) or exercise combined with a structured weight loss program (EX + WL) on CHD risk factors associated with syndrome X. METHODS: A total of 53 men and women were selected from a larger behavioral intervention trial, who showed the hyperinsulinemia, dyslipidemia, and high BP characteristic of syndrome X. Participants were randomly assigned to EX only (n = 21), EX + WL (n = 21), or a waiting list control group (n = 11). Before and following treatment, participants underwent measurement of glucose tolerance, lipid levels, and clinical BP. RESULTS: Hyperinsulinemic responses to glucose challenge were significantly reduced in both the EX + WL group (P<.001) and the EX-only group (P =.003). Participants who showed the largest amount of weight loss showed the most robust improvements in abnormal insulin responses (EX + WL group, 47% reduction; EX-only group, 27% reduction). Diastolic BP was significantly reduced in the EX + WL group (96 +/- 4 to 87 +/- 5 mm Hg [mean +/- SD]; P =.01), but not in the EX-only group (93 +/- 4 to 89 +/- 5 mm Hg [mean +/- SD]; P =.08). Lipid profile was not significantly improved by either intervention. CONCLUSION: These results suggest that EX + WL is an effective treatment for hyperinsulinemia and lowering of diastolic BP in patients with the syndrome X.     

Muscle power of the ankle flexors predicts functional performance in community-dwelling older women

OBJECTIVES: To test the hypothesis that peak power of the ankle flexors is related to physical functioning in older women with functional limitations. DESIGN: A cross-sectional study. SETTING: University-based human physiology laboratory. PARTICIPANTS: Thirty-four older women (75.4 +/- 5.1 years, 67.8 +/- 11.3 kg, body mass index 27.4 +/- 4.5) with self-reported functional limitations. MEASUREMENTS: Plantarflexion (PF) and dorsiflexion (DF) peak power and isometric strength with physical performance (stair climb time, repeated chair rise time, maximal and habitual gait velocity) were determined. An isokinetic dynamometer was used to measure isometric strength, isokinetic peak torque and power of PF and DF at five angular velocities (30 degrees, 60 degrees, 90 degrees, 120 degrees, and 180 degrees.sec-1), and isometric strength. RESULTS: Peak torque for both PF and DF declined with increasing velocity of movement (PF: P <.0001; DF: P <.0001), whereas peak power increased with increasing velocity up to 120 degrees.sec-1. The strongest univariate associations were found between chair rise time and DF peak power (r = 0.50; P <.002), stair climb time and DF peak power (r = 0.49; P <.003), habitual gait velocity and PF isometric strength (r = 0.53; P <.001), and maximal gait and PF isometric strength (r = 0.47; P <.005). Multivariate regression analysis revealed that DF and PF peak power along with the physical functioning and general health scores from the Medical Outcomes Study Short Form were independent predictors of chair and stair climb performance. CONCLUSION: These data suggest that ankle muscle power together with self-reported measures of health and physical functioning are essential components of functional mobility in older women with functional limitations.     

Effects of aerobic exercise training in community-based subjects aged 80 and older: a pilot study

OBJECTIVES: To assess the ability of sedentary, frail subjects aged 80 and older to train in a community-based exercise program and to evaluate clinical factors that predict improvements in peak oxygen consumption (VO2peak). DESIGN: Pretest, posttest. SETTING: Charlestown Retirement Community, Catonsville, Maryland PARTICIPANTS: Twenty-two (11 male, 11 female; mean age +/- standard deviation = 84 +/- 4.0, range 80-92) self-referred. INTERVENTION: Six months of moderate-intensity aerobic exercise training, two to three sessions/week, 20 to 30 minutes per session. Training modes included treadmill walking and/or stationary cycling. MEASUREMENTS: Baseline and follow-up maximal exercise treadmill tests (ETTs) with electrocardiogram monitoring and respiratory gas analysis. RESULTS: Six months of aerobic exercise training resulted in significant increases (mean +/- standard deviation) in ETT duration (11.9 +/- 3.3 vs 15.9 +/- 4.3 minutes; P =.01), VO2peak (1.23 +/- 0.37 vs 1.31 +/- 0.36 L/min; P =.04), and oxygen pulse (9.3 +/- 2.8 vs 10.1 +/- 3.2; P =.03). Mean heart rate was significantly lower during submaximal ETT stages 1 through 4 (P <.05), and resting systolic blood pressure decreased (146 +/- 18 vs 133 +/- 14 mmHg; P =.01) after training. Multiple regression analysis indicated that baseline VO2peak (r = 0.75, P =.002) and the total amount of time spent in exercise training (r = 0.55, P =.008) were independent predictors of the training-related improvements in VO2peak. CONCLUSION: Subjects aged 80 and older can increase aerobic capacity and reduce systolic blood pressure in a community-based exercise program of moderate intensity. The most important predictors of change in VO2peak were baseline VO2peak and the time spent in exercise training. Subjects with a lower baseline VO2peak had the greatest improvements in VO2peak after training.     

Effects of exercise training after open heart surgery on quality of life and exercise tolerance in patients with mitral regurgitation or aortic regurgitation

We conducted a questionnaire survey regarding quality of life (QOL) to evaluate the effects of exercise training on the QOL in patients with valvular heart disease after surgery. This study included 64 consecutive patients who underwent heart surgery. They were divided into two groups: exercise training could (EX(+) group, n = 31) and could not be performed (EX(-) group, n = 33) until 6 months after surgery. To evaluate the QOL and exercise tolerance, we employed "a questionnaire regarding disease and quality of life" developed for Japanese people and cardiopulmonary exercise testing. In our questionnaire survey, the improvement rating (Delta subjective/social index), which was calculated from the difference between the pre-and postoperative values, was greater in the EX(+) group than that in the EX(-) group (4.9 +/- 3.1 versus 1.1 +/- 4.0, P < 0.05). In the changes in exercise tolerance, Delta anaerobic threshold was greater in the EX(+) group (0.79 +/- 0.17 versus -0.02 +/- 0.28, P < 0.01). Moreover, there was a positive correlation between Delta subjective/social index and Delta peak VO(2) (r = 0.62, P < 0.05). We concluded that exercise training for patients after cardiac surgery improves the QOL and exercise tolerance. It is suggested that changes in subjective and social parameters contribute to an exercise training-related improvement in the QOL.     

Differences in the neuromuscular capacity and lean muscle tissue in old and older community-dwelling adults

BACKGROUND: This study investigated whether there was a worsening of the neuromuscular capacity of older adults after the seventh decade of life. METHODS: Fifteen healthy community-dwelling old (< 70 years of age) and 15 older adults (> or = 70 years of age) were assessed for maximal isometric strength (MVC) and force production characteristics, a one-repetition maximum (1-RM) performance, electromyographic (EMG) activity, and bone-free lean tissue (BFLT) mass of the lower extremity. RESULTS: The isometric MVC, 1-RM, and BFLT mass values in the old group were significantly greater than in the older group. In addition, the individual BFLT mass values correlated significantly with the isometric MVC values (r = .85) and the 1-RM scores of the thigh muscle groups (r = .54-.80). The old group generated significantly greater isometric maximal rate of torque development than the older group and performed significantly better at all intervals of the absolute and relative force-time curves. The voluntary muscle activation of the knee extensors of the old group produced significantly higher integrated EMG (iEMG) activity at each epoch in the early iEMG-time curve compared with the old group. CONCLUSIONS: The results suggest that the age-related deterioration in maximal strength measures and rapid force production characteristics in older adults could be related to a reduction in the mass and neural activation of the thigh muscles. The deterioration of the neuromuscular system of community-dwelling older adults may contribute to an increased difficulty in performing daily activities and may increase their risks of tripping and falling.     

Beneficial effects of exercise training in heart failure patients with low cardiac output response to exercise – a comparison of two training models

BACKGROUND: Exercise capacity of patients with chronic heart failure (CHF) correlates poorly with estimates of cardiac function. Yet, it has been suggested that only patients without severely impaired cardiac output (CO) benefit from exercise training. Comparisons of different training models have not been made in the same study. AIMS: To evaluate whether the response to different training models diverges according to the cardiac output response to exercise in patients with chronic heart failure. METHODS: Sixteen CHF patients (63 +/- 11 years) with an ejection fraction of 30 +/- 11% underwent a baseline cardiopulmonary exercise test, right heart catheterization and leg muscle biopsy. Cardiac output (CO) response to exercise was defined as the ratio between CO increase and the increase in oxygen uptake (CO response index) during exercise. Patients were randomized into two training regimens, differing with regard to active muscle mass, i.e. whole body and one-legged exercise. RESULTS: Baseline exercise capacity expressed as W kg-1 correlated with the CO response index (r = 0.51, P < 0.05). Exercise capacity on the cycle ergometer increased in both groups but more in the one-legged than in the two-legged training group (P < 0.05). The improvement in exercise capacity did not correlate with base-line exercise capacity. It correlated with CO response index in the one-legged (r = 0.75, P < 0.01) but not in the two-legged training group. CO response index correlated negatively with the pulmonary capillary wedge pressure at peak exercise (r = - 0.60, P < 0.05). The increase in leg muscle citrate synthase activity after training correlated negatively with the baseline CO response index (r = - 0. 50, P < 0.05). CONCLUSIONS: The improvement of exercise capacity after one-legged training correlates with the CO increase in relation to the O2 uptake before training. In patients with low CO response, individualization of the exercise regimen is needed and the benefits of training a limited muscle mass at a time deserve further study.     

Improving physical function and blood pressure in older adults through cobblestone mat walking: a randomized trial

OBJECTIVES: To determine the relative effects of cobblestone mat walking, in comparison with regular walking, on physical function and blood pressure in older adults. DESIGN: Randomized trial with allocation to cobblestone mat walking or conventional walking. SETTING: General community in Eugene, Oregon. PARTICIPANTS: One hundred eight physically inactive community-dwelling adults aged 60 to 92 (mean age+/-standard deviation=77.5+/-5.0) free of neurological and mobility-limiting orthopedic conditions. INTERVENTION: Participants were randomized to a cobblestone mat walking condition (n=54) or regular walking comparison condition (n=54) and participated in 60-minute group exercise sessions three times per week for 16 consecutive weeks. MEASUREMENTS: Primary endpoint measures were balance (functional reach, static standing), physical performance (chair stands, 50-foot walk, Up and Go), and blood pressure (systolic, diastolic). Secondary endpoint measures were Short Form-12 physical and mental health scores and perceptions of health-related benefits from exercise. RESULTS: At the 16-week posttest, differences between the two exercise groups were found for balance measures (P=.01), chair stands (P<.001), 50-foot walk (P=.01), and blood pressure (P=.01) but not for the Up and Go test (P=.14). Although significant within-group changes were observed in both groups for the secondary outcome measures, there were no differences between intervention groups. CONCLUSION: Cobblestone mat walking improved physical function and reduced blood pressure to a greater extent than conventional walking in older adults. Additional benefits of this walking program included improved health-related quality of life. This new physical activity may provide a therapeutic and health-enhancing exercise alternative for older adults.     

Effects of an ad libitum low-fat, high-carbohydrate diet on body weight, body composition, and fat distribution in older men and women: a randomized controlled trial

BACKGROUND: The efficacy of ad libitum low-fat diets in reducing body weight and fat in overweight and obese adults remains controversial. METHODS: We examined the effect of a 12-week low-fat, high-complex carbohydrate diet alone (HI-CHO) and in combination with aerobic exercise training (HI-CHO + EX) on body weight and composition in 34 individuals with impaired glucose tolerance (20 women and 14 men; mean +/- SEM age, 66 +/- 1 years). Participants were randomly assigned to a control diet (41% fat, 14% protein, 45% carbohydrates, and 7 g of fiber per 1000 kcal), a HI-CHO diet (18% fat, 19% protein, 63% carbohydrates, and 26 g of fiber per 1000 kcal), or a HI-CHO diet plus endurance exercise 4 d/wk, 45 min/d, at 80% peak oxygen consumption (HI-CHO + EX). Participants were provided 150% of estimated energy needs and were instructed to consume food ad libitum. Total food intake, body composition, resting metabolic rate, and substrate oxidation were measured. RESULTS: There was no significant difference in total food intake among the 3 groups and no change in energy intake over time. The HI-CHO + EX and HI-CHO groups lost more body weight (-4.8 +/- 0.9 kg [P=.003] and -3.2 +/- 1.2 kg [P=.02]) and a higher percentage of body fat (-3.5% +/- 0.7% [P=.01] and -2.2% +/- 1.2% [P=.049]) than controls (-0.1 +/- 0.6 kg and 0.2% +/- 0.6%). In addition, thigh fat area decreased in the HI-CHO (P=.003) and HI-CHO + EX (P<.001) groups compared with controls. High carbohydrate intake and weight loss did not result in a decreased resting metabolic rate or reduced fat oxidation. CONCLUSION: A high-carbohydrate diet consumed ad libitum, with no attempt at energy restriction or change in energy intake, results in losses of body weight and body fat in older men and women.     

Feasibility and efficacy of home exercise training before lung volume reduction.

BACKGROUND: Exercise training is recommended before lung volume reduction surgery (LVRS) in patients with emphysema. Unfortunately, many of these patients are referred from remote areas where there is no available rehabilitation program. The authors evaluated the feasibility and efficacy of a minimally supervised home-based exercise training program. METHODS: Twenty-three emphysematous patients (age 61 +/- 6, forced expiratory volume in 1 second = 29 +/- 7% predicted [mean +/- SD]) were recruited from our LVRS program. Measurements of pulmonary function, maximal and submaximal exercise capacity, 6-minute walking distance (6-MWD), muscle strength, and quality of life with the Chronic Respiratory Questionnaire were obtained before and after training. Home-based exercise training program included muscle exercises and aerobic training, and started with detailed teaching while the follow-up was ensured through weekly phone calls and a diary filled by each patient. RESULTS: Significant increases in 6-MWD (P < 0.001), quality of life (P < 0.005), peak work rate (P < 0.05), peak oxygen consumption (P < 0.05), endurance time (P < 0.005), and muscle strength were observed in the home-based exercise training program. CONCLUSIONS: Home-based exercise training for patients in preparation for LVRS was feasible, and induced significant improvement in exercise tolerance and quality of life.     

The effects of progressive strength training and aerobic exercise on muscle strength and cardiovascular fitness in women with fibromyalgia: a pilot study

OBJECTIVE: To determine the safety, feasibility and consequences of a program of progressive strength training and cardiovascular exercise in women with fibromyalgia syndrome (FMS). METHODS: Fifteen women with confirmed FMS were monitored for injury and exercise compliance, and assessed for muscle strength (1-repetition maximum technique), cardiovascular endurance (6-minute walk test), and functional status (Fibromyalgia Impact Questionnaire [FIQ]) before and after a 20-week exercise intervention. RESULTS: Zero injuries and an 81% compliance rate occurred during training. Improvement was seen in muscle strength of the lower (191 +/- 75 to 265 +/- 67 pounds; P < 0.001) and upper (61 +/- 18 to 76 +/- 18 pounds; P < 0.001) body, 6-minute walk distance (530 +/- 80 to 629 +/- 74 meters; P < 0.001), and in FIQ score (44 +/- 9 to 32 +/- 14; P < 0.01). CONCLUSION: A program of progressive strength training and cardiovascular exercise can be safe, well tolerated, and effective at improving muscle strength, cardiovascular endurance and functional status in women with FMS without exacerbating symptoms. This program may also contribute to a reduction in the severity of several symptoms.