The Relationships Between Muscle Power and Physical Activity in Older Men With Chronic Obstructive Pulmonary Disease.

The purpose of this study was to determine the potential relationship between muscle power of the lower extremities and the physical activity in older men with chronic obstructive pulmonary disease (COPD). Forty-four men (70.3 ± 6.7 years old) with moderate-to-severe COPD completed the 6-min walk test (6MWT), BODE (body mass index, obstruction, dyspnea, and exercise), a one-repetition maximum strength of the quadriceps femoris (1RMQF), and muscle power at 50% and 70% 1RMQF. Physical activity was measured using an accelerometer. The 6MWT was associated with muscle power at 50% 1RMQF (r = .40; P = .013) but not muscle power at 70% 1RMQF (r = .24; P = .15) or 1RMQF (r = .13; P = .44). Light-intensity activity was positively correlated with muscle power at 50% 1RMQF (r = .52; P = .001). Lower limb muscle power is associated with the 6MWT and light-intensity activities in older men with COPD.

Effects of Combined Resistance and Endurance Training Versus Resistance Training Alone on Strength, Exercise Capacity, and Quality of Life in Patients With COPD.

PURPOSE: To compare the effects of 12-week training periods (2 d·wk) involving resistance training only with the effects of 12-week training periods involving combined resistance (once weekly) and endurance (once weekly) training on strength, endurance performance, and quality of life. METHODS: Thirty-six patients with moderate-to-severe chronic obstructive pulmonary disease were randomized to combined training (REG), resistance training alone (RG), or control (CG) groups. Patients were tested for maximal strength of the upper and lower extremities, power output of the lower extremities, maximal (Wmax) and submaximal exercise capacity, performance on a 6-minute walk test (6MWT), and quality of life. RESULTS: REG and RG induced similar maximal strength gains. Muscle power increased 19% (P ≤ .01) and Wmax improved 13% (P < .05) in REG. Reductions (P < .05) in the heart rate and blood lactate at a given submaximal workload were observed in REG. Improvements in 6MWT and quality of life were similar in both training groups. CONCLUSIONS: Compared with a twice-weekly resistance training program, the combination of once-weekly resistance and once-weekly endurance training not only produced similar gains in maximal strength, 6MWT performance, and quality of life but also produced improvements in muscle power and endurance performance. These findings may have implications for the prescription of resistance and endurance exercise for patients with chronic obstructive pulmonary disease.

The effects of strength training on central arterial compliance in middle-aged and older adults.

BACKGROUND: Contrary to aerobic exercise, strength training (ST) is associated with decreased central arterial compliance in young men. It is unknown whether ST, with or without concurrent endurance training, would have a similar effect in older adults with reduced baseline arterial compliance. OBJECTIVE: The primary aim of this study was to determine the effect of a ST program on central arterial compliance in middle-aged and older adults. DESIGN: Randomized, controlled intervention study in which 37 healthy, sedentary men and women (52+/-2 years) performed 13 weeks of ST (n=13), ST+aerobic exercise (n=12) or stretching exercises as a control group (n=12). METHODS: Participants were rigorously screened for cardiovascular disease and underwent pre-post testing for carotid arterial compliance (via simultaneous ultrasound and applanation tonometry), carotid-femoral pulse wave velocity, plasma endothelin-1 and angiotensin II concentrations and carotid artery vasoreactivity (cold pressor test). RESULTS: ST performed alone, or in conjunction with aerobic exercise, improved maximal muscle strength and increased total lean body mass (both P<0.01). No significant changes were observed in carotid artery compliance or carotid-femoral pulse wave velocity following ST or ST+aerobic exercise. Carotid artery compliance increased significantly (23%) following stretching which may be attributed to a reduction in carotid pulse pressure. No significant changes were observed in plasma vasoconstrictor hormones or carotid artery vasoreactivity following the interventions. CONCLUSION: Thirteen weeks of moderate ST two or three times per week does not reduce central arterial compliance in middle-aged and older adults.

Resistance training increases basal limb blood flow and vascular conductance in aging humans.

Age-related reductions in basal limb blood flow and vascular conductance are associated with the metabolic syndrome, functional impairments, and osteoporosis. We tested the hypothesis that a strength training program would increase basal femoral blood flow in aging adults. Twenty-six sedentary but healthy middle-aged and older subjects were randomly assigned to either a whole body strength training intervention group (52 +/- 2 yr, 3 men, 10 women) who underwent three supervised resistance training sessions per week for 13 wk or a control group (53 +/- 2 yr, 4 men, 9 women) who participated in a supervised stretching program. At baseline, there were no significant differences in blood pressure, cardiac output, basal femoral blood flow (via Doppler ultrasound), vascular conductance, and vascular resistance between the two groups. The strength training group increased maximal strength in all the major muscle groups tested (P < 0.05). Whole body lean body mass increased (P < 0.05) with strength training, but leg fat-free mass did not. Basal femoral blood flow and vascular conductance increased by 55-60% after strength training (both P < 0.05). No such changes were observed in the control group. In both groups, there were no significant changes in brachial blood pressure, plasma endothelin-1 and angiotensin II concentrations, femoral artery wall thickness, cardiac output, and systemic vascular resistance. Our results indicate that short-term strength training increases basal femoral blood flow and vascular conductance in healthy middle-aged and older adults.

Cigarette smoking, regular exercise, and peripheral blood flow.

Acute and chronic smoking reduces peripheral blood flow and shear stress, contributing to the increased incidence of peripheral arterial disease in smokers. Currently, it is not known whether physical activity status influences peripheral blood flow among chronic smokers. Blood flow was measured using Doppler ultrasound on the common femoral artery in nine young otherwise healthy sedentary smokers (eight males/one female) and nine physically-active smokers (six males/three females). Physically-active smokers performed strenuous exercise 4.4 times/week for 8 h/week. No significant differences in body fat, blood pressure, and total cholesterol were observed between groups. Basal femoral artery blood flow was approximately 50% higher in physically-active smokers compared with sedentary smokers (259+/-108 ml min(-1) versus 173+/-47 ml min(-1), P<0.05). The higher basal femoral artery blood flow in physically-active smokers compared with sedentary smokers was associated with a 47% higher femoral artery vascular conductance (2.99+/-1.2 U versus 2.03+/-0.5 U, P<0.05) and a 39% lower vascular resistance (0.38+/-0.13 U versus 0.53+/-0.15 U, P<0.05). Cardiac output, systemic vascular resistance, femoral intima-media thickness, and plasma norepinephrine concentration were not different between the groups. We concluded that smokers who habitually perform physical activity demonstrate greater levels of peripheral blood flow and peripheral vascular conductance. The findings from the present cross-sectional study suggest that chronic smokers may be able to negate, at least in part, the adverse effects of chronic smoking on the peripheral vasculature by performing regular physical activity.

Arterial compliance of rowers: implications for combined aerobic and strength training on arterial elasticity.

Regular endurance exercise increases central arterial compliance, whereas resistance training decreases it. It is not known how the vasculature adapts to a combination of endurance and resistance training. Rowing is unique, because its training encompasses endurance- and strength-training components. We used a cross-sectional study design to determine arterial compliance of 15 healthy, habitual rowers [50 +/- 9 (SD) yr, 11 men and 4 women] and 15 sedentary controls (52 +/- 8 yr, 10 men and 5 women). Rowers had been training 5.4 +/- 1.2 days/wk for 5.7 +/- 4.0 yr. The two groups were matched for age, body composition, blood pressure, and metabolic risk factors. Central arterial compliance (simultaneous ultrasound and applanation tonometry on the common carotid artery) was higher (P < 0.001) and carotid beta-stiffness index was lower (P < 0.001) in rowers than in sedentary controls. There were no group differences for measures of peripheral (femoral) arterial stiffness. The higher central arterial compliance in rowers was associated with a greater cardiovagal baroreflex sensitivity, as estimated during a Valsalva maneuver (r = 0.54, P < 0.005). In conclusion, regular rowing exercise in middle-aged and older adults is associated with a favorable effect on the elastic properties of the central arteries. Our results suggest that simultaneously performed endurance training may negate the stiffening effects of strength training.

Effects of high intensity resistance training on arterial stiffness and wave reflection in women.

BACKGROUND: Cross-sectional studies reported that chronic resistance training is associated with arterial stiffening in men. These findings are in marked contrast to those found with aerobic exercise and may have important clinical relevance with regard to cardiovascular disease risk. However, the effect of resistance training on arterial stiffness has not been confirmed by interventional studies nor has this relation been investigated in women. METHODS: To determine whether a strength training program increases regional and central arterial stiffness in women, 23 healthy young women (29+/-1 years; mean+/-SD) participated in a high-intensity strength and power training program for 11 weeks. Ten other women (27+/-2 years) served as time controls. RESULTS: In the intervention group, one repetition maximal strength increased 12% to 17% (P<.0001), and leg fat-free mass (via DEXA) increased significantly. Brachial blood pressure (BP) and fasting plasma lipid and lipoprotein concentrations did not change across the 11 weeks. Carotid augmentation index, a measure of arterial wave reflection and arterial stiffness, increased from -8%+/-13% to 1%+/-18% (P<.05), and carotid-femoral pulse wave velocity increased (791+/-88 v 833+/-96 cm/sec; P<.05). There were no changes in femoral-ankle pulse wave velocity, a segmental measure of peripheral arterial stiffness. CONCLUSIONS: We concluded that a high-intensity resistance training program increases arterial stiffness and wave reflection in young healthy women. Our present interventional results are consistent with the previous cross-sectional studies in men in which high-intensity strength training is associated with arterial stiffening.

Acute effects of resistance exercise on arterial compliance.

Decreased central arterial compliance is an emerging risk factor for cardiovascular disease. Resistance training is associated with reductions in the elastic properties of central arteries. Currently, it is not known whether this reduction is from one bout of resistance exercise or from an adaptation to multiple bouts of resistance training. Sixteen healthy sedentary or recreationally active adults (11 men and 5 women, age 27 +/- 1 yr) were studied under parallel experimental conditions on 2 separate days. The order of experiments was randomized between resistance exercise (9 resistance exercises at 75% of 1 repetition maximum) and sham control (seated rest in the exercise room). Baseline hemodynamic values were not different between the two experimental conditions. Carotid arterial compliance (via simultaneous B-mode ultrasound and applanation tonometry) decreased and beta-stiffness index increased (P < 0.01) immediately and 30 min after resistance exercise. Immediately after resistance exercise, carotid systolic blood pressure increased (P < 0.01), although no changes were observed in brachial systolic blood pressure at any time points. These measures returned to baseline values within 60 min after the completion of resistance exercise. No significant changes in these variables were observed during the sham control condition. These results indicate that one bout of resistance exercise acutely decreases central arterial compliance, but this effect is sustained for <60 min after the completion of resistance exercise.

Age-related declines in anaerobic muscular performance: weightlifting and powerlifting.

PURPOSE: One approach to studying the effects of aging on physiological functional capacity (PFC) in humans is to analyze the peak physical performance of trained athletes with increasing age. The primary aim of the present study was to determine weightlifting and powerlifting performance with increasing age in both men and women. METHODS: We performed a retrospective analysis of top age-group weightlifting and powerlifting records compiled from the U.S. Weightlifting and U.S. Powerlifting Organizations. RESULTS: Regression analyses showed that in both men and women weightlifting and powerlifting performance declined curvilinearly and linearly, respectively. The rate and the overall magnitude of declines in performance with age were markedly greater (P < 0.05) in weightlifting than in powerlifting. The rates of age-related decline in muscular power were not different between upper body (bench press) and lower body (squat). Similarly, the age-related declines were not different between snatch and clean and jerk in weightlifting events. The magnitude of the declines with age was greater (P < 0.05) in women than in men in weightlifting; no such sex-related differences were observed in powerlifting performance. CONCLUSIONS: The findings in this cross-sectional study indicate that 1) peak anaerobic muscular power, as assessed by peak lifting performance, decreases progressively even from earlier ages than previously thought; 2) the overall magnitude of decline in peak muscular power appears to be greater in tasks requiring more complex and powerful movements; 3) the age-related rates of decline are greater in women than in men only in the events that require more complex and explosive power; and 4) upper- and lower-body muscular power demonstrate similar rate of decline with age.