The blood pressure response of older men to maximum and sub-maximum strength testing.

Strength testing is commonly used to determine the muscular strength of older individuals participating in a resistance training program. The purpose of this study was to non-invasively examine and compare the blood pressure (BP) and heart rate (HR) response of maximum and sub-maximum strength tests in older men. Twenty-four healthy men aged 70-80 yr were recruited for the study. Participants completed a 1 repetition maximum (RM) strength test and four days later a sub-maximum strength test on an incline squat. Systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR were measured by plethysmography during and immediately after the strength tests. SBP, DBP and HR were (P<0.001) higher during the 1RM and sub-maximum strength tests compared to resting values. Twenty seconds post 1RM, SBP and HR were higher than resting values. Twenty seconds post sub-maximum strength testing SBP and DBP were lower (P<0.02) and HR (P<0.001) was higher than resting values. SBP, DBP and HR were higher (P<0.001) during sub-maximum strength testing compared to 1RM testing. Twenty seconds post testing, SBP and DBP were lower (P<0.001) and HR was higher (P<0.001) for the sub-maximum strength tests compared to the 1RM. The results of our study demonstrate that sub-maximum strength testing resulted in greater changes in BP and HR compared to 1RM strength testing. The lower cardiovascular stress experienced during the 1RM shows that this may be a safer method of testing compared to sub-maximum strength testing in men aged 70-80 yr.

The effect of strength training and short-term detraining on maximum force and the rate of force development of older men.

This study examined the effect of strength training (ST) and short-term detraining on maximum force and rate of force development (RFD) in previously sedentary, healthy older men. Twenty-four older men (70-80 years) were randomly assigned to a ST group (n = 12) and C group (control, n = 12). Training consisted of three sets of six to ten repetitions on an incline squat at 70-90% of one repetition maximum three times per week for 16 weeks followed by 4 weeks of detraining. Regional muscle mass was assessed before and after training by dual-energy X-ray absorptiometry. Training increased RFD, maximum bilateral isometric force, and force in 500 ms, upper leg muscle mass and strength above pre-training values (14, 25, 22, 7, 90%, respectively; P < 0.05). After 4 weeks detraining all neuromuscular variables were significantly (P < 0.05) lower than after 16 weeks training but remained significantly (P < 0.05) higher than pre-training levels except for RFD which had returned to pre-training levels. These findings demonstrate that high-intensity ST can improve maximum force and RFD of older men. However, older individuals may lose some neuromuscular performance after a period of short-term detraining and that resistance exercise should be performed on a regular basis to maintain training adaptations.

Can aerobic training improve muscle strength and power in older men?

This study examined the effect of aerobic training on leg strength, power, and muscle mass in previously sedentary, healthy older men (70-80 yr). Training consisted of 30-45 min of cycle ergometry at 50-70% maximal oxygen consumption (VO2max), 3 times weekly for 16 wk, then 4 wk detraining, or assignment to a nontraining control group (n = 12 both groups). Training increased leg strength, leg power, upper leg muscle mass, and VO2max above pretraining values (21%, 12%, 4%, and 15%, respectively; p < .05). However, all gains were lost after detraining, except for some gain in VO2max. This suggests that cycle ergometry is sufficient stimulus to improve neuromuscular function in older men, but gains are quickly lost with detraining. For the older population cycle ergometry provides the means to not only increase aerobic fitness but also increase leg strength and power and upper leg muscle mass. However, during periods of inactivity neuromuscular gains are quickly lost.

Resistance training reduces the blood pressure response of older men during submaximum aerobic exercise.

OBJECTIVE: The objective of this study was to determine whether 16 weeks of resistance training (RT) can reduce the blood pressure response and improve the cardiovascular function of men aged 70-80 years during submaximum aerobic exercise. METHODS: Twenty-four men aged between 70 and 80 years were randomly assigned to an RT group (n = 12) and control group (n = 12). Training consisted of three sets of six to 10 repetitions at 70-90% of one repetition maximum, three times per week, on an incline squat machine for 16 weeks. Blood pressure and cardiovascular function were assessed during submaximum cycle exercise at 40 W, and 50 and 70% of maximum oxygen consumption (VO2max) before training and after 16 weeks of training. Leg strength and VO2max were assessed every 4 weeks of the 16-week study. RESULTS: At 40 W, heart rate, systolic blood pressure, and rate pressure product were lower and stroke volume was significantly higher after 16 weeks of training. At 50% VO2max, heart rate and rate pressure product were lower after 16 weeks of training and at 70% VO2max, cycle ergometry power, VO2, and arterio-venous oxygen difference were higher after 16 weeks of training. Leg strength significantly increased after 16 weeks of training. CONCLUSION: Sixteen weeks of RT significantly reduces the blood pressure response and improves the cardiovascular function of older men during submaximum aerobic exercise. Therefore, RT not only increases muscular strength and hypertrophy but also provides significant cardiovascular benefits for older individuals.

Strength training improves submaximum cardiovascular performance in older men.

PURPOSE: To determine if 16 weeks of strength training can improve the cardiovascular function of older men during submaximum aerobic exercise. METHODS: Twenty four men aged 70-80 yr were randomly assigned to a strength training (ST; n = 12) and control group (C; n = 12). Training consisted of 3 sets of 6 - 10 repetitions at 70% to 90% of 1RM, 3 times per week, on an incline squat machine for 16 weeks, followed by 4 weeks detraining. Leg strength and maximum oxygen consumption (VO2 max) were assessed every 4 weeks of the 20-week study. Cardiovascular function was assessed during submaximum cycle exercise at 40 Watts, 50% and 70% of VO2 max before training, after 16 weeks training, and after 4 weeks detraining. RESULTS: At 40 Watts, heart rate (HR), systolic blood pressure, and rate pressure product (RPP) were lower and stroke volume (SV) significantly higher after 16 weeks training and 4 weeks detraining: at 50% VO2 max, HR and RPP were lower after 16 weeks training and 4 weeks detraining: at 70% VO2 max, cycle ergometry power, VO2 and arterio-venous oxygen difference (a - vO2 ) were higher after 16 weeks training. Leg strength and VO2 max increased after 16 weeks training, with leg strength remaining above pre-training levels after 4-weeks detraining. CONCLUSIONS: Sixteen weeks of strength training significantly improves the cardiovascular function of older men. Therefore strength training not only increases muscular strength and hypertrophy but also provides significant cardiovascular benefits for older individuals.

Reliability of orthostatic responses in healthy men aged between 65 and 75 years.

The purpose of this study was to investigate the short-, medium- and long-term reproducibility of cardiovascular responses during 90 degrees head-up tilt (HUT) in healthy older men. Twenty-eight healthy male subjects aged 69 (95% confidence intervals, 68-70) years participated in the study. Eight subjects underwent duplicate 90 degrees HUT tests on consecutive days, while 20 subjects underwent four 90 degrees HUT tests performed at baseline, and after 1 week, 1 month and 1 year. Following a 20-min supine resting period, each subject was rapidly tilted to the upright vertical position (90 degrees HUT) and remained in that position for 15 min. Beat-by-beat recordings of mean (MAP), systolic (SBP) and diastolic (DBP) pressures were made via Finapres, while heart rate (HR) was monitored continuously from an electrocardiogram. No significant test-retest differences (P > 0.05) were observed for the changes in HR, MAP, SBP or DBP during 90 degrees HUT. These measurements demonstrated high reproducibility (intraclass correlation coefficient, r = 0.91-0.99, P < 0.05). The supine resting and tilted HR, MAP, SBP and DBP over the 1-week, 1-month and 1-year period were not significantly different (P > 0.05) from baseline, and demonstrated high reproducibility (intraclass correlation coefficient, r = 0.82-0.98, P < 0.05). The results of this study demonstrate that in healthy older men, cardiovascular responses during orthostasis are highly reproducible, and this reproducibility is maintained over a 12-month period. These findings demonstrate that the 90 degrees HUT test offers a reproducible method of monitoring longitudinal orthostatic responses in healthy older men.

Excess post-exercise oxygen consumption in spinal cord-injured men.

This study examined excess post-exercise oxygen consumption (EPOC) following arm cranking in men who had a traumatic spinal cord injury (SCI). Six physically active SCI men with a lesion level between T10 and T12 and six able-bodied (AB) men who were matched according to upper body peak VO(2) performed 30 min of arm-cranking at 65-70% peak VO(2). Baseline measurements were recorded during the last 10 min of a 40-min seated rest. Subjects remained seated during recovery for 40 min or until VO(2) returned to baseline, whichever was longer. Plasma lactate concentration was measured at rest, at the end of exercise, and at 10, 20 and 40 min of recovery. EPOC duration was not significantly different ( P>0.05) between SCI [23.2 (7.9) min; mean (SE)] and AB [35.0 (15.4) min] men, nor was there a significant group difference in EPOC magnitude [36.8 (7.8) kJ for SCI and 53.0 (22.8) kJ for AB]. There was no significant difference in recovery heart rate (HR) or respiratory exchange ratio (RER) between SCI and AB. However, HR measured at the end of the EPOC period was significantly elevated ( P<0.001) and RER significantly lower ( P<0.03) for both groups when compared to baseline. Lactate concentration was not significantly different between the groups at any sampling period. The findings suggest that physically active SCI men have a similar energy expenditure and time frame for recovery from arm crank exercise as their AB counterparts. Similar to what has been reported following lower body exercise, arm crank exercise elicits a higher HR and lower RER at end-EPOC when compared to pre-exercise values.